WO2025166229A1

WO2025166229A1 - Tricyclic amidino compounds as prmt5 inhibitors

Info

Publication number: WO2025166229A1
Application number: PCT/US2025/014121
Authority: WO
Inventors: Paul A. Barsanti; Melissa Fleury; Joshua P. G. TAYGERLY
Original assignee: Ideaya Biosciences Inc
Current assignee: Ideaya Biosciences Inc
Priority date: 2024-02-02
Filing date: 2025-01-31
Publication date: 2025-08-07
Anticipated expiration: 2026-08-02

Abstract

Provided herein are compounds of Formula (I) or a pharmaceutically acceptable salt thereof. The provided compounds are useful Protein arginine N-methyltransferase 5 (PRMT5) inhibitors. Also, disclosed are pharmaceutical compositions comprising such compounds and methods of making such compounds. Additional utilities and advantages are described herein.

Description

TRICYCLIC AMIDINO COMPOUNDS AS PRMT5 INHIBITORS

CROSS-REFERENCES TO RELATED APPLICATIONS

[0001] This application claims the benefit of priority under 35 U.S.C. § 119(e) to U.S. Provisional Application Nos. 63/549,386 filed February 02, 2024 and 63/745,533 filed January 15, 2025, the contents of each is incorporated by reference in its entirety for all purposes.

STATEMENT AS TO RIGHTS TO INVENTIONS MADE UNDER FEDERALLY SPONSORED RESEARCH AND DEVELOPMENT

[0002] NOT APPLICABLE

REFERENCE TO A "SEQUENCE LISTING," A TABLE, OR A COMPUTER PROGRAM LISTING APPENDIX SUBMITTED ON A COMPACT DISK

[0003] NOT APPLICABLE

BACKGROUND

[0004] Cancer is a leading cause of death throughout the world. A limitation of prevailing therapeutic approaches, e.g. chemotherapy and immunotherapy is that their cytotoxic effects are not restricted to cancer cells and adverse side effects can occur within normal tissues. Consequently, novel strategies are needed to better target cancer cells.

[0005] Synthetic lethality arises when a combination of deficiencies in the expression or activity of two or more genes leads to cell death, whereas a deficiency in only one of these genes does not. The concept of synthetic lethality originates from studies in drosophila model systems in which a combination of mutations in two or more separate genes leads to cell death (in contrast to viability, which occurs when only one of the genes is mutated or deleted). More recently, a multitude of studies have explored maladaptive genetic changes in cancer cells that render them vulnerable to synthetic-lethality approaches. These tumorspecific genetic defects lead to the use of targeted agents that induce the death of tumor cells while sparing normal cells. [0006] Protein arginine N-methyltransferase 5 (PRMT5) is a methyl transferase that uses s- adenosyl methionine (SAM) as a methyl donor. PRMT5 catalyzes symmetrical dimethylarginine in a number of substrates including histone and non-histone proteins. The activity of PRMT5 has been associated with development and cancer as well as other biological functions.

[0007] Due to the role of PRMT5 in human diseases such as cancer, several inhibitors of PRMT5 have been developed. A number of these compounds target the SAM-PRMT5 complex either through competitive inhibition with SAM or the protein substrate. A challenge for these inhibitors is that the SAM-PRMT5 complex forms in both normal and cancer cells, making it difficult to selectively inhibit PRMT5 in only cancer cells.

[0008] Chromosome 9p21 encompasses, among others, CDKN2A (cyclin dependent kinase inhibitor 2A), and homozygous deletion of 9p21 genomic locus is implicated in about 15% of all cancers. MTAP is located within the vicinity of the CDKN2A on chromosome 9p21 and is frequently co-deleted with CDKN2A deletion. The MTAP protein (methylthioadenosine phosphorylase) is an enzyme involved in polyamine metabolism, and the deletion of MTAP results in the accumulation of 5 ’methylthioadenosine (MTA) in the cell.

[0009] Seemingly due to structural similarities between SAM and MTA, PRMT5 is competitively inhibited by MTA. Cells with an MTAP deletion have increased levels of MTA, thereby partially inhibiting PRMT5. A new generation of PRMT5 inhibitors targeting the MTA-PRMT5 complex in MTAP deleted cancers are being developed. These MTA cooperative inhibitors selectively bind to the MTA-PRMT5 complex, effectively inhibiting PRMT5 in MTAP deleted cells, while leaving normal cells relatively unaffected. Inhibition of PRMT5 with MTA cooperative inhibitors leads to cell death and provides a new synthetic lethality approach for the treatment of MTAP deleted cancers.

[0010] Despite a mechanistic understanding and approach for the treatment of MTAP deleted cancers, there remains a need in the art to develop selective MTA cooperative PRMT5 inhibitors possessing appropriate selectivity and providing suitable therapeutic windows for treatment. The present disclosure addresses these needs and provides related advantages.

SUMMARY

[0011] In one aspect, provided herein is a compound of Formula (I): or a pharmaceutically acceptable salt thereof. The definitions for X¹, X², X³, X⁴, X⁵, X⁶, ring A, ring B, R⁷, p, R⁸, q, and R⁹ are further described herein.

[0012] In another aspect, provided herein is a pharmaceutical composition comprising a compound of Formula (I) or a pharmaceutically acceptable salt thereof, or a subembodiment thereof, and one or more pharmaceutically acceptable excipients.

[0013] In another aspect, provided herein is a method of treating a disease treatable by inhibition of protein arginine N-methyltransferase 5 (PRMT5) in a patient in need thereof comprising administering to the patient a therapeutically effective amount of a compound of Formula (I) or a pharmaceutically acceptable salt thereof, a subembodiment thereof, or a pharmaceutical composition as defined herein.

[0014] In another aspect, provided herein is a method of treating an MTAP null cancer in a patient in need thereof comprising administering to the patient a therapeutically effective amount of a compound of Formula (I) or a pharmaceutically acceptable salt thereof, a subembodiment thereof, or a pharmaceutical composition as defined herein.

[0015] In another aspect, provided herein is a method of treating a cancer in a patient in need thereof, wherein the cancer is characterized by a reduction or absence of MTAP gene expression, an absence of the MTAP gene, an absence of MTAP protein, a reduced level of MTAP protein, a reduced function of MTAP protein, or a combination thereof, comprising administering to the patient a therapeutically effective amount of a compound of Formula (I) or a pharmaceutically acceptable salt thereof, a subembodiment thereof, or a pharmaceutical composition as defined herein.

[0016] In another aspect, provided herein is a method of treating cancer in a patient in need thereof comprising administering to the patient a therapeutically effective amount of a compound of Formula (I) or a pharmaceutically acceptable salt thereof, a subembodiment thereof, or a pharmaceutical composition as defined herein. [0017] In another aspect, provided herein is a compound of Formula (I) or a pharmaceutically acceptable salt thereof, a subembodiment thereof, or a pharmaceutical composition as defined herein, for use in the treatment of a disease treatable by inhibition of protein arginine N-methyltransferase 5 (PRMT5).

[0018] In another aspect, provided herein is a compound of Formula (I) or a pharmaceutically acceptable salt thereof, a subembodiment thereof, or a pharmaceutical composition as defined herein, for use in the treatment of an MTAP null cancer.

[0019] In another aspect, provided herein is a compound of Formula (I) or a pharmaceutically acceptable salt thereof, a subembodiment thereof, or a pharmaceutical composition as defined herein, for use in the treatment of cancer in a patient, wherein the cancer is characterized by a reduction or absence of MTAP gene expression, an absence of the MTAP gene, an absence of MTAP protein, a reduced level of MTAP protein, a reduced function of MTAP protein, or a combination thereof.

[0020] In another aspect, provided herein is a compound of Formula (I) or a pharmaceutically acceptable salt thereof, a subembodiment thereof, or a pharmaceutical composition as defined herein, for use in the treatment of cancer.

[0021] In another aspect, provided herein is a compound of Formula (I) or a pharmaceutically acceptable salt thereof, a subembodiment thereof, or a pharmaceutical composition as defined herein, for use in therapy.

[0022] In another aspect, provided herein is a compound of Formula (I) or a pharmaceutically acceptable salt thereof, a subembodiment thereof, or a pharmaceutical composition as defined herein, in the manufacture of a medicament for use in the treatment of a disease treatable by inhibition of protein arginine N-methyltransferase 5 (PRMT5).

[0023] In another aspect, provided herein is a compound of Formula (I) or a pharmaceutically acceptable salt thereof, a subembodiment thereof, or a pharmaceutical composition as defined herein, in the manufacture of a medicament for use in the treatment of an MTAP null cancer.

[0024] In another aspect, provided herein is a compound of Formula (I) or a pharmaceutically acceptable salt thereof, a subembodiment thereof, or a pharmaceutical composition as defined herein, in the manufacture of a medicament for use in the treatment of cancer in a patient, wherein the cancer is characterized by a reduction or absence of MTAP gene expression, an absence of the MTAP gene, an absence of MTAP protein, a reduced level of MTAP protein, a reduced function of MTAP protein, or a combination thereof.

[0025] In another aspect, provided herein is a compound of Formula (I) or a pharmaceutically acceptable salt thereof, a subembodiment thereof, or a pharmaceutical composition as defined herein, in the manufacture of a medicament for use in the treatment of cancer.

[0026] In another aspect, provided herein is a compound of Formula (I) or a pharmaceutically acceptable salt thereof, a subembodiment thereof, or a pharmaceutical composition as defined herein, for use in the production of a protein arginine N- methyltransferase 5 (PRMT5) inhibitory effect.

[0027] In another aspect, provided herein is the use of a compound of Formula (I) or a pharmaceutically acceptable salt thereof, a subembodiment thereof, or a pharmaceutical composition as defined herein, in the manufacture of a medicament for use in the production of a protein arginine N-methyltransferase 5 (PRMT5) inhibitory effect.

[0028] In another aspect, provided herein is a method of inhibiting protein arginine N- methyltransferase 5 (PRMT5) in vitro or in vivo, said method comprising contacting a cell with an effective amount of a compound of Formula (I) or a pharmaceutically acceptable salt thereof, a subembodiment thereof, or a pharmaceutical composition as defined herein.

[0029] In another aspect, provided herein is a method of inhibiting cell profiferation in vitro or in vivo, said method comprising contacting a cell with an effective amount of a compound of Formula (I) or a pharmaceutically acceptable salt thereof, a subembodiment thereof, or a pharmaceutical composition as defined herein.

[0030] In some embodiments, the methods, uses, and medicament described herein are for the treatment of human cancers.

[0031] In another aspect, provided are methods of synthesizing a compound of Formula (I) or a pharmaceutically acceptable salt thereof, or a subembodiment thereof as defined herein.

[0032] In another aspect, provided herein is a compound of Formula (I) or a pharmaceutically acceptable salt thereof, or a subembodiment thereof obtainable by, or obtained by, or directly obtained by a method of synthesis as defined herein. [0033] In another aspect, provided herein are novel intermediates as defined herein which are suitable for use in any one of the synthetic methods as set out herein.

[0034] Preferred, suitable, and optional features of any one particular aspect of the present invention are also preferred, suitable, and optional features of any other aspect.

BRIEF DESCRIPTION OF THE DRAWINGS

[0035] NOT APPLICABLE

DETAILED DESCRIPTION OF THE INVENTION

[0036] Before the present invention is further described, it is to be understood that the invention is not limited to the particular embodiments set forth herein, and it is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only, and is not intended to be limiting.

[0037] Where a range of values is provided, it is understood that each intervening value, to the tenth of the unit of the lower limit unless the context clearly dictates otherwise, between the upper and lower limit of that range and any other stated or intervening value in that stated range, is encompassed within the invention. The upper and lower limits of these smaller ranges may independently be included in the smaller ranges, and are also encompassed within the invention, patient to any specifically excluded limit in the stated range. Where the stated range includes one or both of the limits, ranges excluding either or both of those included limits are also included in the invention. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

[0038] The publications discussed herein are provided solely for their disclosure prior to the filing date of the present application. Further, the dates of publication provided may be different from the actual publication dates, which may need to be independently confirmed.

GENERAL

[0039] Provided herein are compounds of Formula (I) or a pharmaceutically acceptable salt thereof, or a subembodiment thereof for inhibition of protein arginine N-methyltransferase 5 (PRMT5), and pharmaceutical compositions comprising the same. Also provided herein are, for example, methods of treating or preventing a disease, disorder or condition, or a symptom thereof, mediated by inhibition of PRMT5. Further provided herein are methods treating or preventing a disease, disorder or condition, or a symptom thereof treatable by inhibition of PRMT5.

DEFINITIONS

[0040] Unless otherwise indicated, the following terms are intended to have the meaning set forth below. Other terms are defined elsewhere throughout the specification.

[0041] Unless specifically indicated otherwise, the group “ _{as use}d j_n any _{one o}f the structures in Table 1, the Examples, or moieties disclosed herein, refers to methyl (-CH3) where the wavy line is the point of attachment to the remainder of the molecule.

[0042] As used herein, the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise. It is further noted that the claims may be drafted to exclude any optional element. As such, this statement is intended to serve as antecedent basis for use of such exclusive terminology such as “solely,” “only” and the like in connection with the recitation of claim elements, or use of a “negative” limitation.

[0043] The term "alkyl", by itself or as part of another substituent, refers to, unless otherwise stated, a saturated straight or branched chain hydrocarbon radical, having the number of carbon atoms designated i.e. C1-8 means one to eight carbons). Alkyl can include any number of carbons, such as C1-2, C1.3, CM, C1-5, C1-6, C1-7, C1-8, C1-9, C1-10, C2-3, C2-4, C2-5, C2-6, C3-4, C3-5, C3-6, C4-5, C4-6 and C5-6. Examples of alkyl groups include methyl, ethyl, n- propyl, isopropyl, n-butyl, t-butyl, isobutyl, sec-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, and the like.

[0044] The term “alkylene” refers to a straight or branched, saturated hydrocarbon radical having the number of carbon atoms indicated, and linking at least two other groups, i.e., a divalent hydrocarbon radical. The two moieties linked to the alkylene can be linked to the same atom or different atoms of the alkylene group. Representative alkylene groups include, but are not limited to, methylene, ethylene, propylene, isopropylene, butylene, isobutylene, sec-butylene, pentylene and hexylene.

[0045] The term “alkynyl” refers to either a straight chain or branched hydrocarbon having at least 2 carbon atoms and at least one triple bond and having the number of carbon atom indicated (i.e., C2-6 means to two to six carbons). Alkynyl can include any number of carbons, such as C2, C2-3, C2-4, C2-5, C2-6, C2-7, C2-8, C2-9, C2-10, C3, C3-4, C3-5, C3-6, C4, C4-5, C4-6, C5, C5-6, and C6. Examples of alkynyl groups include, but are not limited to, acetylenyl, propynyl, 1-butynyl, 2-butynyl, butadiynyl, 1-pentynyl, 2-pentynyl, isopentynyl,

1.3-pentadiynyl, 1,4-pentadiynyl, 1-hexynyl, 2-hexynyl, 3-hexynyl, 1,3-hexadiynyl,

1.4-hexadiynyl, 1,5-hexadiynyl, 2,4-hexadiynyl, or 1,3,5-hexatriynyl.

[0046] The term "cycloalkyl" refers to a non-aromatic, saturated hydrocarbon ring having the indicated number of ring atoms (e.g., C3-6 cycloalkyl). For example, “C3-10 cycloalkyl” refers to a cycloalkyl group containing 3 to 10 carbon atoms as ring vertices and the term “C3- 7 cycloalkyl” refers to a cycloalkyl group having 3 to 7 carbon atoms as ring vertices. Representative examples include, but are not limited to, cyclopropyl, cyclobutyl, cyclopentyl, and the like.

[0047] The term "halo" or "halogen," by itself or as part of another substituent, mean, unless otherwise stated, a fluorine, chlorine, bromine, or iodine atom.

[0048] The term "haloalkyl," refers to alkyl, as defined above, that is substituted having one or more halogen atoms, which may be the same or different, at one or more carbon atoms of an alkyl and includes monohaloalkyl and polyhaloalkyl. For example, the term "C1-4 haloalkyl" includes trifluoromethyl, 2,2,2-trifluoroethyl, 4-chlorobutyl, 3-bromopropyl, and the like.

[0049] The term “haloalkyl(OH),” refers to haloalkyl, as defined above, that is further substituted with a hydroxy (OH) group.

[0050] The terms "alkoxy," and "haloalkoxy" refer to alkyl and haloalkyl groups respectively, each as defined herein, that is attached to the remainder of the molecule via an oxygen atom, for example -O-alkyl or -O-haloalkyl.

[0051] The term “aryl” refers to a monocyclic or bicyclic, hydrocarbon, aromatic radical. An aryl group may contain 6 to 14 carbon atoms. For example, “Ce-io aryl” refers to an aryl moiety having 6 to 10 carbon atoms as ring vertices. Non-limiting examples of aryl groups include phenyl and naphthyl.

[0052] The term "heteroaryl" refers refers to a moiety comprising an aromatic monocyclic or bicyclic radical, containing 5 to 10 ring atoms, including at least one heteroatom independently selected from nitrogen, oxygen, and sulfur. A heteroaryl group can be attached to the remainder of the molecule through a heteroatom. Non-limiting examples of heteroaryl groups include pyridyl, pyridazinyl, pyrazinyl, pyrimindinyl, triazinyl, quinolinyl, quinoxalinyl, quinazolinyl, cinnolinyl, phthalazinyl, benzotriazinyl, purinyl, benzimidazolyl, benzopyrazolyl, benzotriazolyl, benzisoxazolyl, isobenzofuryl, isoindolyl, indolizinyl, benzotriazinyl, thienopyridinyl, thienopyrimidinyl, pyrazolopyrimidinyl, imidazopyridines, benzothiaxolyl, benzofuranyl, benzothienyl, indolyl, quinolyl, isoquinolyl, isothiazolyl, pyrazolyl, indazolyl, pteridinyl, imidazolyl, triazolyl, tetrazolyl, oxazolyl, isoxazolyl, thiadiazolyl, pyrrolyl, thiazolyl, furyl, thienyl and the like.

[0053] The term "5- or 6-membered heteroaryl” refers to a moiety comprising an aromatic monovalent monocyclic radical, containing 5 or 6 ring atoms, including at least one carbon atom and containing one, two, or three heteroatoms independently selected from nitrogen, oxygen, and sulfur. Selected 5-membered heteroaryl groups contain three heteroatoms. Exemplary groups include, but are not limited to, furanyl, thienyl, pyrrolyl, imidazolyl, pyrazolyl, triazolyl, tetrazolyl, oxazolyl, thiazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrazinyl, pyrimidinyl, and triazinyl.

[0054] The term "heterocycloalkyl" or “heterocyclyl” refers to a saturated or partially unsaturated 3 to 10 membered monocyclic or bicyclic ring having from one to four heteroatoms independently selected from N, O, and S and the remaining ring atom being carbon. The nitrogen and sulfur atoms are optionally oxidized, and the nitrogen atom(s) are optionally quatemized and one or two ring carbon atoms of the heterocyclic ring may be replaced by -C=(O) group. However, heterocycloalkyl groups are not aromatic. Non limiting examples of heterocycloalkyl groups include pyrrolidine, imidazolidine, pyrazolidine, butyrolactam, valerolactam, imidazolidinone, hydantoin, dioxolane, piperidine, 1,4-dioxane, morpholine, thiomorpholine, thiomorpholine-S-oxide, thiomorpholine-S,S-oxide, piperazine, pyran, pyridone, 3-pyrroline, thiopyran, pyrone, tetrahydrofuran, tetrahydrothiophene, , and the like. A heterocycloalkyl group can be attached to the remainder of the molecule through a ring carbon or a heteroatom.

[0055] The term "hydroxyalkyl," refers to an alkyl, as defined above, that is substituted with one or two hydroxy. For example, the term “hydroxyCi-4 alkyl” or “C1-4 hydroxyalkyl” is meant to include hydroxymethyl, 1-, or 2-hydroxy ethyl, 1,2-dihydroxy ethyl, hydroxypropyl, and the like. [0056] The term “optionally substituted” indicates that a group may be unsubstituted or substituted with one or more substituents as defined herein. The term “substituted” in reference to a group indicates that a hydrogen atom attached to a member atom within a group is replaced by one of the defined substituents. In the case where groups may be selected from a number of alternative groups, the selected groups may be the same or different.

[0057] The term "oxo" refers to an oxygen atom with a double bond to the point of attachment (O=).

[0058] The term "fused tricyclic moiety" refers to a ring system comprising three fused rings having the number of ring atoms and heteroatoms indicated, wherein each ring in the fused system can be unsaturated, partially unsaturated, or saturated. Therefore, each ring in the fused tricyclic moiety can be aromatic or non aromatic.

[0059] As used herein, a wavy line, ">~w ", that intersects a single, double or triple bond in any chemical structure depicted herein, represent the point attachment of the single, double, or triple bond to the remainder of the molecule. Additionally, a bond extending to the center of a ring (e.g., a phenyl ring) is meant to indicate attachment at any of the available ring vertices. One of skill in the art will understand that multiple substituents shown as being attached to a ring will occupy ring vertices that provide stable compounds and are otherwise sterically compatible.

[0060] The term “pharmaceutically acceptable” refers to those compounds (including salts), materials, compositions, and dosage forms which are, within the scope of sound medical judgment, suitable for use in contact with the tissues of human beings and animals without excessive toxicity, irritation, or other problem or complication, commensurate with a reasonable benefit/risk ratio.

[0061] As used herein, the term “pharmaceutically acceptable salt” refers to salts that retain the desired biological activity of the subject compound and exhibit minimal undesired toxicological effects. Such pharmaceutically acceptable salt may be prepared in situ during the final isolation and purification of the compound, or by separately reacting the purified compound in its free acid or free base form with a suitable base or acid, respectively. When compounds disclosed herein contain relatively acidic functionalities, base addition salts can be obtained by contacting the neutral form of such compounds with a sufficient amount of the desired base, either neat or in a suitable inert solvent. Examples of salts derived from pharmaceutically-acceptable inorganic bases include aluminum, ammonium, calcium, copper, ferric, ferrous, lithium, magnesium, manganic, manganous, potassium, sodium, zinc. Salts derived from pharmaceutically-acceptable organic bases include salts of primary, secondary and tertiary amines, including substituted amines, cyclic amines, naturally-occuring amines, such as arginine, betaine, caffeine, choline, N,N" -dibenzylethylenediamine, diethylamine, 2- diethylaminoethanol, 2-dimethylaminoethanol, ethanolamine, ethylenediamine, N- ethyhnorpholine, N-ethylpiperidine, glucamine, glucosamine, histidine, hydrabamine, isopropylamine, lysine, methylglucamine, morpholine, piperazine, piperidine, polyamine resins, procaine, purines, theobromine, triethylamine, trimethylamine, tripropylamine, tromethamine. When compounds of the present disclosure contain relatively basic functionalities, acid addition salts can be obtained by contacting the neutral form of such compounds with a sufficient amount of the desired acid, either neat or in a suitable inert solvent. Examples of pharmaceutically acceptable acid addition salts include those derived from inorganic acids like hydrochloric, hydrobromic, nitric, carbonic, monohydrogen carbonic, phosphoric, monohydrogen phosphoric, dihydrogen phosphoric, sulfuric, monohydrogen sulfuric, hydriodic, or phosphorous acids, as well as the salts derived from relatively nontoxic organic acids like acetic, propionic, isobutyric, malonic, benzoic, succinic, suberic, fumaric, mandelic, phthalic, benzenesulfonic, p-tolylsulfonic, citric, tartaric, methanesulfonic. Also included are salts of amino acids such as arginate, and salts of organic acids like glucuronic or galactunoric acids (see, for example, Berge, S.M., et al, “Pharmaceutical Salts”, Journal of Pharmaceutical Science, 1977, 66, 1-19). Certain specific compounds of the present disclosure contain both basic and acidic functionalities that allow the compounds to be converted into either base or acid addition salts.

[0062] The neutral forms of the compounds may be regenerated by contacting the salt with a base or acid and isolating the parent compound in the conventional manner. The parent form of the compound differs from the various salt forms in certain physical properties, such as solubility in polar solvents, but otherwise the salts are equivalent to the parent form of the compound for the purposes of the present disclosure.

[0063] Certain compounds of Formula (I) possess asymmetric carbon atoms (optical centers) or double bonds; the racemates, diastereomers, geometric isomers, regioisomers, and individual isomers (e.g., separate enantiomers) are all intended to be encompassed within the scope of the present disclosure. When a stereochemical depiction is shown, it is meant to refer to the compound in which one of the isomers is present and substantially free of the other isomer. “Substantially free of’ another isomer indicates at least an 80/20 ratio of the two isomers, more preferably 90/10, or 95/5 or more. In some embodiments, one of the isomers will be present in an amount of at least 99%.

[0064] Certain compounds of Formula (I) can exist in unsolvated forms as well as solvated forms, including hydrated forms. In general, the solvated forms are equivalent to unsolvated forms and are intended to be encompassed within the scope of the present disclosure. Certain compounds of Formula (I) may exist in multiple crystalline or amorphous forms. In general, all physical forms are equivalent for the uses contemplated by the present disclosure and are intended to be within the scope of the present disclosure.

[0065] Certain compounds of the present disclosure can exist as tautomers and/or geometric isomers. All possible tautomers and cis and trans isomers, as individual forms and mixtures thereof are within the scope of this disclosure.

[0066] Compounds of Formula (I) or a subembodiment thereof may also contain unnatural proportions of atomic isotopes at one or more of the atoms that constitute such compounds. Unnatural proportions of an isotope may be defined as ranging from the amount found in nature to an amount consisting of 100% of the atom in question. Exemplary isotopes that can be incorporated into compounds of the present disclosure, such as a compound of Formula (I) (and any embodiment thereof disclosed herein including specific compounds) include isotopes of hydrogen, carbon, nitrogen, oxygen, phosphorus, sulfur, fluorine, chlorine, and iodine, such as ²H, ³H, ⁿC, ¹³C, ¹⁴C, ¹³N, ¹⁵N, ¹⁵0, ¹⁷0, ¹⁸0, ³²P, ³³P, ³⁵S, ¹⁸F, ³⁶C1, ¹²³I, and ¹²⁵1, respectively. Such isotopic variations can provide additional utilities to those described elsewhere within this application. For instance, isotopic variants of the compounds of the invention may find additional utility, including but not limited to, as diagnostic and/or imaging reagents, or as cytotoxic/radiotoxic therapeutic agents. Additionally, isotopic variants of Formula (I) or a subembodiment thereof can have altered pharmacokinetic and pharmacodynamic characteristics which can contribute to enhanced safety, tolerability or efficacy during treatment. Isotopically-labeled compounds (e.g., those labeled with ³H and ¹⁴C) can be useful in compound or substrate tissue distribution assays. Tritiated (i.e., ³H) and carbon- 14 (i.e., ¹⁴C) isotopes can be useful for their ease of preparation and detectability. Further, substitution with heavier isotopes such as deuterium (i.e., ²H) may afford certain therapeutic advantages resulting from greater metabolic stability (e.g., increased in vivo halflife or reduced dosage requirements). In some embodiments, in compounds disclosed herein, including in Table 1 below one or more hydrogen atoms are replaced by ²H or ³H, or one or more carbon atoms are replaced by ¹³C- or ¹⁴C-enriched carbon. Positron emitting isotopes such as ¹⁵O, ¹³N, ⁿC, and ¹⁵F are useful for positron emission tomography (PET) studies to examine substrate receptor occupancy. Isotopically labeled compounds can generally be prepared by following procedures analogous to those disclosed in the Schemes or in the Examples herein, by substituting an isotopically labeled reagent for a non-isotopically labeled reagent. All isotopic variations of Formula (I) or a subembodiment thereof, whether radioactive or not, are intended to be encompassed within the scope of the present invention.

[0067] The terms “patient” or “subject” are used interchangeably to refer to a human or a non-human animal (e.g., a mammal). Examples of patients include humans, livestock such as cows, goats, sheep, pigs, and rabbits, and companion animals such as dogs, cats, rabbits, and horses. In one embodiment, the patient or subject is a human.

[0068] “Disease” as used herein is intended to be generally synonymous, and is used interchangeably with, the terms “disorder,” “syndrome,” and “condition” (as in medical condition), in that all reflect an abnormal condition of the human or animal body or of one of its parts that impairs normal functioning, is typically manifested by distinguishing signs and symptoms, and causes the human or animal to have a reduced duration or quality of life.

[0069] “In need of treatment” as used herein refers to a judgment made by a physician or other caregiver that a subject requires or will benefit from treatment. This judgment is made based on a variety of factors that are in the realm of the physician’s or caregiver’s expertise.

[0070] The terms “administration”, “administer” and the like, as they apply to, for example, a subject, cell, tissue, organ, or biological fluid, refer to contact of, for example, a compound of Formula (I) or a pharmaceutically acceptable salt thereof, a pharmaceutical composition comprising the same, or a diagnostic agent to the subject, cell, tissue, organ, or biological fluid. In the context of a cell, administration includes contact (e.g., in vitro or ex vivo) of a reagent to the cell, as well as contact of a reagent to a fluid, where the fluid is in contact with the cell.

[0071] The terms “proliferative disorder,” “proliferative condition,” and “cell proliferation’ are used interchangeably herein and pertain to an unwanted or uncontrolled cellular proliferation of excessive or abnormal cells which is undesired, such as, neoplastic or hyperplastic growth, whether in vitro or in vivo. Examples of proliferative conditions include, but are not limited to, pre-malignant and malignant cellular proliferation, including but not limited to, malignant neoplasms and tumors, cancers, leukemias, psoriasis, bone diseases, fibroproliferative disorders (e.g., of connective tissues), and atherosclerosis. Any type of cell may be treated, including but not limited to, lung, colon, breast, ovarian, prostate, gastric, liver, pancreas, brain, and skin.

[0072] The terms “treat”, “treating”, treatment” and the like refer to a course of action (such as administering an inhibitor of PRMT5 or a pharmaceutical composition comprising the same) initiated after a disease, disorder or condition, or a symptom thereof, has been diagnosed, observed, and the like so as to eliminate, reduce, suppress, mitigate, or ameliorate, either temporarily or permanently, at least one of the underlying causes of a disease, disorder, or condition afflicting a patient, or at least one of the symptoms associated with a disease, disorder, condition afflicting a patient. Thus, treatment includes inhibiting (e.g., arresting the development or further development of the disease, disorder or condition or clinical symptoms association therewith) an active disease.

[0073] The terms “prevent”, “preventing”, “prevention” and the like refer to a course of action (such as administering a PRMT5 inhibitor or a pharmaceutical composition comprising the same) initiated in a manner (e.g., prior to the onset of a disease, disorder, condition or symptom thereof) so as to prevent, suppress, inhibit or reduce, either temporarily or permanently, a patient’s risk of developing a disease, disorder, condition or the like (as determined by, for example, the absence of clinical symptoms) or delaying the onset thereof, generally in the context of a patient predisposed to having a particular disease, disorder or condition. In certain instances, the terms also refer to slowing the progression of the disease, disorder or condition, or inhibiting progression thereof to a harmful or otherwise undesired state.

[0074] The terms “inhibiting” and “reducing,” or any variation of these terms in relation of PRMT5, includes any measurable decrease or complete inhibition to achieve a desired result. For example, there may be a decrease of about 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 99%, or more, reduction of PRMT5 activity compared to normal. [0075] The phrase “therapeutically effective amount” as used herein means the amount of a compound of Formula (I) or a pharmaceutically acceptable salt thereof, either alone or as part of a pharmaceutical composition and either in a single dose or as part of a series of doses, in an amount capable of having any detectable, positive effect on any symptom, aspect, or characteristic of a disease, disorder or condition when administered to the patient. It may vary depending on the compound, the disease and its severity and the age and weight of the subject to be treated. The therapeutically effective amount can be ascertained by measuring relevant physiological effects, and it can be adjusted in connection with the dosing regimen and diagnostic analysis of the patient’s condition, and the like. By way of example, measurement of the serum level of a compound Formula (I) or a pharmaceutically acceptable salt thereof (or, e.g., a metabolite thereof) at a particular time post-administration may be indicative of whether a therapeutically effective amount has been used.

[0076] The term “antibody” means an immunoglobulin and is a molecule containing an antigen-binding site immunospecifically binding to an antigen. The class of the antibody of the present disclosure may be any of IgG, IgE, IgM, IgD, IgA, and IgY and is preferably IgG. The subclass of the antibody of the present disclosure may be any of IgGl, IgG2, IgG3, IgG4, IgAl, and IgA2 and is preferably IgGl or IgG2. The antibody may be derived from any species, and preferred examples of the species can include humans, rats, mice, and rabbits. When the antibody is derived from other than human species, it is preferably chimerized or humanized using a well-known technique. The antibody of the present disclosure may be a polyclonal antibody or a monoclonal antibody. In an embodiment, the antibody is a monoclonal antibody. The antibody of the present disclosure is capable of targeting tumor cells. In an embodiment, the antibody of the present disclosure is conjugated with an antitumor compound having antitumor activity via a linker, the antibody preferably possesses one or more of a property of recognizing a tumor cell, a property of binding to a tumor cell, a property of internalizing in a tumor cell, and a property of damaging a tumor cell. In an embodiment, the antibody is a monoclonal antibody that is reactive with a target antigen or epitope of an antigen expressed on a cancer or malignant cell. Techniques for preparing monoclonal antibodies against target antigen are known in the art. Non limiting target antigens are B7-H3, B7-H4, Trop-2, PSMA, BCMA, folate receptor, AXL, EGF receptor (ErbBl), ErbB2, ErbB3, EGFRvIII, FGFR, EpCAM, HER-2, HER-3, tissue factor (TF), CD19, CD22, CD25, ILR2, ANTXR1, ROR1, 5T4, CD30, CD33, CD79b, CD74, CD138, CD56, CD70, CD166, CEACAM5, GPNMB, Claudin-18, folate receptor alpha (FRa), c-Met, Nectin-4, Mesothelin, delta-like ligand 3 (DLL3), PTK7, GPNMB, Ley, CA6, CanAng, Av integrin, SLC44A4, CEACAM5, AGS- 16, Anti-Cripto, Carbonic Anhydrase 9, Mesotheilin, TENB2, 5T4, VEGF, insulin-like growth factor (ILGF), MUC1 and TA-MUC1.

COMPOUNDS

[0077] In one aspect, the present disclosure provides a compound of Formula (I): or a pharmaceutically acceptable salt thereof, wherein

X¹ is C(R^laR^lb), O, or NR¹;

X² is C(R^2aR^2b), O, or NR²;

X³ is C(R^3aR^3b), O, or NR³;

X⁴ is C(R^4aR^4b), O, NR⁴, S, S(O), or S(O)₂;

X⁵ is C(R^5aR^5b), O, NR⁵, S, S(O), or S(O)₂;

X⁶ is C(R^6aR^6b), O, NR⁶, S, S(O), or S(O)₂;

R¹, R², and R³ are each independently H or Ci-4 alkyl;

R^la,R^lb, R^2a,R^2b, R^3a, and R^3b are each independently H, Ci-4 alkyl, halo, or Ci-4 haloalkyl;

R⁴, R⁵, and R⁶ are each independently H, Ci-4 alkyl, or Ci-4 hydroxyalkyl;

R^4a,R^4b, R^5a _>R^5b _> R^6a, and R^6b are each independently H, Ci-4 alkyl, C1-4 haloalkyl, CH hydroxyalkyl, or C1-4 haloalkyl(OH); ring A is heterocycloalkyl having 4 to 7 ring members with at least 1 nitrogen atom ring vertex, and 0 to 2 additional heteroatoms as ring vertices, wherein each additional heteroatom is independently N, O, S, S(O), or S(O)₂; ring B is Ce-io aryl or heteroaryl having 5 to 10 ring members with 1 to 4 heteroatom ring vertices, wherein each heteroatom is independently N, O, or S; p is 0, 1, 2, or 3; q is 0, 1, 2, or 3; each R⁷ is independently C1-6 alkyl, C1-6 haloalkyl, halo, OH, C1-6 alkoxy, C1-6 haloalkoxy, -C(O)Ci-₆ alkyl, -C(O)Ci-₆ haloalkyl, -C(O)OCi-₆ alkyl, or -C(O)OCi-₆ haloalkyl; each R⁸ is independently Ci-6 alkyl, Ci-6 haloalkyl, halo, OH, CN, Ci-6 alkoxy, Ci-6 haloalkoxy, C2-6 alkynyl, -O-C2-6 alkynyl, C3-6 cycloalkyl, -O-C3-6 cycloalkyl, - C(O)Ci-₆ alkyl, -C(O)Ci-₆ haloalkyl, -C(O)OCi-₆ alkyl, -C(O)OCi-₆ haloalkyl, or heterocycloalkyl having 4 to 6 ring members with 1 to 3 heteroatom ring vertices, wherein each heteroatom is independently N, O, or S, and wherein each of the C3-6 cycloalkyl, -O-C3-6 cycloalkyl, and heterocycloalkyl is substituted with 0, 1, or 2 R^8a; each R^8a is independently C1.4 alkyl, halo, C1-4 haloalkyl, CN, OH, or C1-4 alkoxy; alternatively, one R⁷ attached to ring A and one R⁸ attached to ring B combine to form ring C, wherein ring C is C4-7 cycloalkyl or heterocycloalkyl having 4 to 7 ring members with 1 to 3 heteroatom ring vertices, wherein each heteroatom is independently N, O, S, S(O), or S(O)₂, wherein ring C is substituted with 0, 1, 2, or 3 R^7a, and ring A, ring B, and ring C form a fused tricyclic moiety; each R^7a is independently C1-4 alkyl, halo, C1-4 haloalkyl, OH, or C1-4 alkoxy; alternatively, two R^7a groups attached to the same carbon atom combine to form oxo; and R⁹ is H, Ci-4 alkyl, halo, or C1-4 haloalkyl.

[0078] In some aspects, provided herein are compounds of Formula (I): or a pharmaceutically acceptable salt thereof, wherein

X¹ is C(R^laR^lb), O, or NR¹;

X² is C(R^2aR^2b), O, or NR²;

X³ is C(R^3aR^3b), O, or NR³;

X⁴ is C(R^4aR^4b), O, NR⁴, S, S(O), or S(O)₂;

X⁵ is C(R^5aR^5b), O, NR⁵, S, S(O), or S(O)₂;

X⁶ is C(R^6aR^6b), O, NR⁶, S, S(O), or S(O)₂;

R¹, R², and R³ are each independently H or C1-4 alkyl;

R^la,R^lb, R^2a,R^2b, R^3a, and R^3b are each independently H, C1.4 alkyl, halo, or C1.4 haloalkyl;

R⁴, R⁵, and R⁶ are each independently H, C1-4 alkyl, or C1-4 hydroxyalkyl; R^4a , R^4b, R^5a,R^5b, R^6a, and R^6b are each independently H, Ci-4 alkyl, Ci-4 haloalkyl, C hydroxyalkyl, or Ci-4 haloalkyl(OH); ring A is heterocycloalkyl having 4 to 7 ring members with at least 1 nitrogen atom ring vertex, and 0 to 2 additional heteroatoms as ring vertices, wherein each additional heteroatom is independently N, O, S, S(O), or S(O)2; ring B is Ce-io aryl or heteroaryl having 5 to 10 ring members with 1 to 4 heteroatom ring vertices, wherein each heteroatom is independently N, O, or S; p is 0, 1, 2, or 3; q is 0, 1, 2, or 3; each R⁷ is independently Ci-6 alkyl, Ci-6 haloalkyl, halo, Ci-6 alkoxy, Ci-6 haloalkoxy, -C(O)Ci-₆ alkyl, -C(O)Ci-₆ haloalkyl, -C(O)OCi-₆ alkyl, or -C(O)OCi-₆ haloalkyl; each R⁸ is independently Ci-6 alkyl, Ci-6 haloalkyl, halo, CN, Ci-6 alkoxy, Ci-6 haloalkoxy, C3- 6 cycloalkyl, -O-C3-6 cycloalkyl, -C(O)Ci-6 alkyl, -C(O)Ci-6 haloalkyl, -C(O)OCi-6 alkyl, -C(O)OCi-6 haloalkyl, or heterocycloalkyl having 4 to 6 ring members with 1 to 3 heteroatom ring vertices, wherein each heteroatom is independently N, O, or S, and wherein the heterocycloalkyl is substituted with 0, 1, or 2 R^8a; each R^8a is independently C1-4 alkyl, halo, or C1-4 haloalkyl; alternatively, one R⁷ attached to ring A and one R⁸ attached to ring B combine to form ring C, wherein ring C is C4-7 cycloalkyl or heterocycloalkyl having 4 to 7 ring members with 1 to 3 heteroatom ring vertices, wherein each heteroatom is independently N, O, S, S(O), or S(O)₂, wherein ring C is substituted with 0, 1, 2, or 3 R^7a, and ring A, ring B, and ring C form a fused tricyclic moiety; each R^7a is independently C1-4 alkyl, halo, or C1-4 haloalkyl; alternatively, two R^7a groups attached to the same carbon atom combine to form oxo; and R⁹ is H, C1.4 alkyl, halo, or C1-4 haloalkyl.

[0079] In some aspects, provided herein are compounds of Formula (I): or a pharmaceutically acceptable salt thereof, wherein X¹ is C(R^laR^lb), O, or NR¹; X² is C(R^2aR^2b), O, or NR²;

X³ is C(R^3aR^3b), O, or NR³;

X⁴ is C(R^4aR^4b), 0, NR⁴, S, S(O), or S(O)₂;

X⁵ is C(R^5aR^5b), O, NR⁵, S, S(O), or S(O)₂;

X⁶ is C(R^6aR^6b), O, NR⁶, S, S(O), or S(O)₂;

R¹, R², and R³ are each independently H or C1-4 alkyl;

R⁴, R⁵, and R⁶ are each independently H, C1-4 alkyl, or C1-4 hydroxyalkyl;

R^4a , R^4b, R^5a,R^5b, R^6a, and R^6b are each independently H, C1-4 alkyl, C1-4 haloalkyl, CH hydroxyalkyl, or C1-4 haloalkyl(OH); ring A is heterocycloalkyl having 4 to 7 ring members with at least 1 nitrogen atom ring vertex, and 0 to 2 additional heteroatoms as ring vertices, wherein each additional heteroatom is independently N, O, S, S(O), or S(O)₂; ring B is Ce-io aryl or heteroaryl having 5 to 10 ring members with 1 to 4 heteroatom ring vertices, wherein each heteroatom is independently N, O, or S; p is 0, 1, 2, or 3; q is 0, 1, 2, or 3; each R⁷ is independently C1-6 alkyl, C1-6 haloalkyl, halo, C1-6 alkoxy, C1-6 haloalkoxy, -C(O)Ci-₆ alkyl, -C(O)Ci-₆ haloalkyl, -C(O)OCi-₆ alkyl, or -C(O)OCi-₆ haloalkyl; each R⁸ is independently C1-6 alkyl, C1-6 haloalkyl, halo, Ci-6 alkoxy, C1-6 haloalkoxy, - C(O)Ci-₆ alkyl, -C(O)Ci ₆ haloalkyl, -C(O)OCi ₆ alkyl, -C(O)OCi-₆ haloalkyl, or heterocycloalkyl having 4 to 6 ring members with 1 to 3 heteroatom ring vertices, wherein each heteroatom is independently N, O, or S, and wherein the heterocycloalkyl is substituted with 0, 1, or 2 R^8a; each R^8a is independently C1.4 alkyl, halo, or C1.4 haloalkyl; alternatively, one R⁷ attached to ring A and one R⁸ attached to ring B combine to form ring C, wherein ring C is C4-7 cycloalkyl or heterocycloalkyl having 4 to 7 ring members with 1 to 3 heteroatom ring vertices, wherein each heteroatom is independently N, O, S, S(O), or S(O)₂, wherein ring C is substituted with 0, 1, 2, or 3 R^7a, and ring A, ring B, and ring C form a fused tricyclic moiety; each R^7a is independently C1-4 alkyl, halo, or C1-4 haloalkyl; alternatively, two R^7a groups attached to the same carbon atom combine to form oxo; and R⁹ is H, Ci-4 alkyl, halo, or C1-4 haloalkyl. [0080] In some embodiments of Formula (I), one R⁷ attached to ring A and one R⁸ attached to ring B combine to form ring C, wherein ring C is C4-7 cycloalkyl or heterocycloalkyl having 4 to 7 ring members with 1 to 3 heteroatom ring vertices, wherein each heteroatom is independently N, O, S, S(O), or S(O)2, wherein ring C is substituted with 0, 1, 2, or 3 R^7a, and ring A, ring B, and ring C form a fused tricyclic moiety.

[0081] In some embodiments, the compound is represented by Formula (la): or the pharmaceutically acceptable salt thereof, wherein p is 0, 1, or 2; q is 0, 1, or 2; and ring A, ring B, ring C, X¹, X², X³, X⁴, X⁵, X⁶, R⁷, R^7a, R⁸, and R⁹ are each defined in Formula (I) and described in any one of the embodiments thereof.

[0082] In some aspects, provided herein are compounds of Formula (la): or a pharmaceutically acceptable salt thereof, wherein

X¹ is C(R^laR^lb), O, or NR¹;

X² is C(R^2aR^2b), O, or NR²;

X³ is C(R^3aR^3b), O, or NR³;

X⁴ is C(R^4aR^4b), O, NR⁴, S, S(O), or S(O)₂;

X⁵ is C(R^5aR^5b), O, NR⁵, S, S(O), or S(O)₂;

X⁶ is C(R^6aR^6b), O, NR⁶, S, S(O), or S(O)₂;

R¹, R², and R³ are each independently H or C1.4 alkyl;

R^la,R^lb, R^2a,R^2b, R^3a, and R^3b are each independently H, C1-4 alkyl, halo, or C1-4 haloalkyl;

R⁴, R⁵, and R⁶ are each independently H, C1-4 alkyl, or C1-4 hydroxyalkyl; R^4a , R^4b, R^5a,R^5b, R^6a, and R^6b are each independently H, Ci-4 alkyl, Ci-4 haloalkyl, C hydroxyalkyl, or Ci-4 haloalkyl(OH); ring A is heterocycloalkyl having 4 to 7 ring members with at least 1 nitrogen atom ring vertex, and 0 to 2 additional heteroatoms as ring vertices, wherein each additional heteroatom is independently N, O, or S; ring B isphenyl or heteroaryl having 5 to 6 ring members with 1 to 3 heteroatom ring vertices, wherein each heteroatom is independently N, O, or S; ring C is fused to (a) two adjacent ring vertices of ring A and (b) two adjacent ring vertices of ring B; and ring C is C4-7 cycloalkyl or heterocycloalkyl having 4 to 7 ring members with 1 to 3 heteroatom ring vertices, wherein each heteroatom is independently N, O, or S; p is 0, 1, or 2; q is 0, 1, or 2; each R⁷ is independently C1-6 alkyl, C1-6 haloalkyl, halo, OH, C1-6 alkoxy, C1-6 haloalkoxy, -C(O)Ci-₆ alkyl, -C(O)Ci-6 haloalkyl, -C(O)OCi-6 alkyl, or -C(O)OCi-₆ haloalkyl; each R^7a is independently C1-4 alkyl, halo, CM haloalkyl, OH, or C1-4 alkoxy; alternatively, two R^7a groups attached to the same carbon atom combine to form oxo; each R⁸ is independently C1-6 alkyl, C1-6 haloalkyl, halo, OH, CN, C1-6 alkoxy, C1-6 haloalkoxy, C2-6 alkynyl, -O-C2-6 alkynyl, C3-6 cycloalkyl, -O-C3-6 cycloalkyl, - C(O)Ci-₆ alkyl, -C(O)Ci-₆ haloalkyl, -C(O)OCi-₆ alkyl, -C(O)OCi-₆ haloalkyl, or heterocycloalkyl having 4 to 6 ring members with 1 to 3 heteroatom ring vertices, wherein each heteroatom is independently N, O, or S, and wherein each of the C3-6 cycloalkyl, -O-C3-6 cycloalkyl, and heterocycloalkyl is substituted with 0, 1, or 2 R^8a; each R^8a is independently C1.4 alkyl, halo, C1-4 haloalkyl, CN, OH, or C1-4 alkoxy; and R⁹ is H, C1.4 alkyl, halo, or C1-4 haloalkyl.

[0083] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (la) or a subembodiment thereof, wherein: each R⁷ is independently C1-6 alkyl, C1-6 haloalkyl, halo, C1-6 alkoxy, C1-6 haloalkoxy, -C(O)Ci-₆ alkyl, -C(O)Ci-₆ haloalkyl, -C(O)OCi-₆ alkyl, or -C(O)OCi-₆ haloalkyl; each R^7a is independently C1.4 alkyl, halo, or C1.4 haloalkyl; alternatively, two R^7a groups attached to the same carbon atom combine to form oxo; each R⁸ is independently C1-6 alkyl, C1-6 haloalkyl, halo, CN, C1-6 alkoxy, C1-6 haloalkoxy, C3- 6 cycloalkyl, -O-C3-6 cycloalkyl, -C(O)Ci-6 alkyl, -C(O)Ci-6 haloalkyl, -C(O)OCi-6 alkyl, -C(O)OCi-6 haloalkyl, or heterocycloalkyl having 4 to 6 ring members with 1 to 3 heteroatom ring vertices, wherein each heteroatom is independently N, O, or S, and wherein the heterocycloalkyl is substituted with 0, 1, or 2 R^8a; each R^8a is independently Ci-4 alkyl, halo, or Ci-4 haloalkyl; and

R⁹ is H, Ci-4 alkyl, halo, or Ci-4 haloalkyl.

[0084] In some embodiments, the compound is represented by Formula (Ial-1): or the pharmaceutically acceptable salt thereof, wherein X^a is O, NH, N(CI-4 alkyl), CH2, or CHR⁷; p is 0, 1, or 2; q is 0, 1, or 2; and ring C, X¹, X², X³, X⁴, X⁵, X⁶, R⁷, R^7a, R⁸, and R⁹ are each defined in Formula (I) and described in any one of the embodiments thereof.

[0085] In some embodiments, the compound is represented by Formula (la 1-2): (Ial-2), or the pharmaceutically acceptable salt thereof, wherein X^a is O, NH, N(CI-4 alkyl), CH2, or CHR⁷; p is 0, 1, or 2; q is 0, 1, or 2; and ring C, X¹, X², X³, X⁴, X⁵, X⁶, R⁷, R^7a, R⁸, and R⁹ are each defined in Formula (I) and described in any one of the embodiments thereof.

[0086] In some embodiments, the compound is represented by Formula (Ia2-1):

or the pharmaceutically acceptable salt thereof, wherein X^a is O, NH, N(CI-4 alkyl ), CH2, or CHR⁷; X^7a and X^7b are each independently absent, O, CH2, or CHR^7a, provided that X^7a and X^7b are not each O; p is 0, 1, or 2; q is 0, 1, or 2; and X¹, X², X³, X⁴, X⁵, X⁶, R⁷, R^7a, R⁸, and R⁹ are each defined in Formula (I) and described in any one of the embodiments thereof.

[0087] In some embodiments, the compound is represented by Formula (Ia2-2): or the pharmaceutically acceptable salt thereof, wherein X^a is O, NH, N(CI-4 alkyl), CH2, or CHR⁷; X^7a and X^7b are each independently absent, O, CH2, or CHR^7a, provided that X^7a and X^7b are not each O; p is 0, 1, or 2; q is 0, 1, or 2; and X¹, X², X³, X⁴, X⁵, X⁶, R⁷, R^7a, R⁸, and R⁹ are each defined in Formula (I) and described in any one of the embodiments thereof.

[0088] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I), or any one of subformulae (e.g., (la), (Ial-1), (lal- 2), (Ia2-1), (Ia2-2), (lb), and (Ibl)), or a subembodiment thereof, wherein no more than two of X¹, X², and X³ are N. In some embodiments, no more than two of X¹, X², and X³ are O. In some embodiments, at least one of X¹, X², and X³ comprises a carbon atom (e.g., X¹ is C(R^laR^lb), X² is C(R^2aR^2b), or X³ is C(R^3aR^3b)). In some embodiments, X¹ is C(R^laR^lb); X² is C(R^2aR^2b), O, or NR²; and X³ is C(R^3aR^3b). In some embodiments, X¹ is NR¹; X² is C(R^2aR^2b); and X³ is O.

[0089] Unless specifically indicated otherwise, embodiments or subembodiments related to Formula (I) are applicable to any one of Formulae (la), (Ial-1), (Ial-2), (Ia2-1), (Ia2-2), (lb), (Ibl), (Ila), (Ila- 1), and (IIa-2). [0090] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein X¹ is C(R^laR^lb) or NR¹.

[0091] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein X¹ is NR¹.

[0092] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein R¹ is H or methyl.

[0093] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein R¹ is H.

[0094] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein X¹ is NR¹; and R¹ is H. In some embodiments, X¹ is NH.

[0095] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein X¹ is C(R^laR^lb).

[0096] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein R^1a and R^lb are each independently H, methyl, ethyl, fluoro, chloro, or bromo.

[0097] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein R^la and R^lb are each independently H, methyl, fluoro, chloro, or trifluoromethyl.

[0098] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein R^la and R^lb are each H.

[0099] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein X¹ is C(R^laR^lb); and R^la and R^lb are each H. In some embodiments, X¹ is CH2. [0100] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein R^la is methyl, and R^lb is H.

[0101] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein X¹ is O.

[0102] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein X² is NR². In some embodiments, R² is H or methyl. In some embodiments, R² is H.

[0103] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein X² is NR²; and R² is H. In some embodiments, X² is NH.

[0104] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein X² is C(R^2aR^2b) or O.

[0105] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein X² is O.

[0106] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein X² is C(R^2aR^2b).

[0107] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein R^2a and R^2b are each independently H, methyl, ethyl, fluoro, chloro, or bromo.

[0108] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein R^2a and R^2b are each independently H, methyl, fluoro, chloro, or trifluoromethyl.

[0109] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein R^2a and R^2b are each H. [0110] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein X² is C(R^2aR^2b); and R^2a and R^2b are each H. In some embodiments, X² is CH2.

[0111] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein R^2a is methyl, and R^2b is H.

[0112] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein X³ is C(R^3aR^3b) or NR³.

[0113] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein X³ is NR³.

[0114] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein R³ is H or methyl.

[0115] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein X³ is C(R^3aR^3b).

[0116] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein R^3a and R^3b are each independently H, methyl, ethyl, fluoro, chloro, or bromo.

[0117] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein R^3a and R^3b are each independently H, methyl, fluoro, chloro, or trifluoromethyl.

[0118] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein R^3a and R^3b are each H.

[0119] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein X³ is C(R^3aR^3b); and R^3a and R^3b are each H. In some embodiments, X³ is CFh. [0120] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein R^3a is methyl, and R^3b is H.

[0121] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein X³ is O.

[0122] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein X¹ is C(R^laR^lb); X² is C(R^2aR^2b), O, or NR²; and X³ is C(R^3aR^3b). In some embodiments, X¹ is CH₂; X² is O, NH, or CH₂; and X³ is CH₂.

[0123] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I), or any one of subformulae (e.g., (la), (Ial-1), (lal- 2), (Ia2-1), (Ia2-2), (lb), and (Ibl)), or a subembodiment thereof, wherein no more than two of X⁴, X⁵, and X⁶ are N. In some embodiments, no more than two of X⁴, X⁵, and X⁶ are O. In some embodiments, at least one of X⁴, X⁵, and X⁶ comprises a carbon atom (e.g., X⁴ is C(R^4aR^4b), X⁵ is C(R^5aR^5b), or X⁶ is C(R^6aR^6b)). In some embodiments, X⁴ is C(R^4aR^4b); X⁵ is O or NR⁴; and X⁶ is C(R^6aR^6b). In some embodiments, X¹ is X⁴ is C(R^4aR^4b); X⁵ is O; and X⁶ is C(R^6aR^6b).

[0124] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein X⁴ is C(R^4aR^4b), O, or NR⁴.

[0125] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein X⁴ is O.

[0126] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein X⁴ is NR⁴.

[0127] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein R⁴ is H or methyl.

[0128] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein R⁴ is H. [0129] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein X⁴ is C(R^4aR^4b).

[0130] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein R^4a and R^4b are each independently H, methyl, ethyl, fluoro, chloro, or bromo.

[0131] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein R^4a and R^4b are each independently H, methyl, fluoro, chloro, or trifluoromethyl.

[0132] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein R^4a and R^4b are each H.

[0133] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein X⁴ is C(R^4aR^4b); and R^4a and R^4b are each H. In some embodiments, X⁴ is CH2.

[0134] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein R^4a is methyl, and R^4b is H.

[0135] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein X⁴ is C(R^4aR^4b); R^4a is methyl; and R^4b is H. In some embodiments, X⁴ is CH(CH3).

[0136] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein X⁵ is C(R^5aR^5b), O, or NR⁵.

[0137] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein X⁵ is O.

[0138] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein X⁵ is NR⁵. [0139] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein R⁵ is H or methyl.

[0140] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein R⁵ is H.

[0141] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein X⁵ is C(R^5aR^5b).

[0142] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein R^5a and R^5b are each independently H, methyl, ethyl, fluoro, chloro, or bromo.

[0143] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein R^5a and R^5b are each independently H, methyl, fluoro, chloro, or trifluoromethyl.

[0144] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein R^5a and R^5b are each H.

[0145] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein X⁵ is C(R^5aR^5b); and R^5a and R^5b are each H. In some embodiments, X⁵ is CH2.

[0146] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein R^5a is methyl, and R^5b is H.

[0147] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein X⁵ is C(R^5aR^5b); R^5a is methyl; and R^5b is H. In some embodiments, X⁵ is CH(CH3).

[0148] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein X⁶ is C(R^6aR^6b), O, or NR⁶. [0149] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein X⁶ is O.

[0150] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein X⁶ is NR⁶.

[0151] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein R⁶ is H or methyl.

[0152] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein R⁶ is H.

[0153] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein X⁶ is C(R^6aR^6b).

[0154] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein R^6a and R^6b are each independently H, methyl, ethyl, fluoro, chloro, or bromo.

[0155] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein R^6a and R^6b are each independently H, methyl, fluoro, chloro, or trifluoromethyl.

[0156] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein R^6a and R^6b are each H.

[0157] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein X⁶ is C(R^6aR^6b); and R^6a and R^6b are each H. In some embodiments, X⁶ is CFh.

[0158] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein R^6a is methyl, and R^6b is H. [0159] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein X⁶ is C(R^6aR^6b); R^6a is methyl; and R^6b is H. In some embodiments, X⁶ is CH CHs).

[0160] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein X⁴ is C(R^4aR^4b); X^s is O; X⁶ is C(R^6aR^6b); and R^4a, R^4b, R^6a, and R^6b are each independently H or Ci-4 alkyl. In some embodiments, X⁴ is CHR^4a; X⁵ is O; X⁶ is CHR^6a; and R^4a and R^6a are each independently H or C1-4 alkyl. In some embodiments, X⁴ is CHR^4a; X⁵ is O; X⁶ is CH2; and R^4a is H or C1-4 alkyl. In some embodiments, X⁴ is CH2 or CH(CH3); X⁵ is O; and X⁶ is CH2 or CH(CH3). In some embodiments, X⁴ is CH2; X⁵ is O; and X⁶ is CH2. In some embodiments, X⁴ is CH(CH₃); X⁵ is O; and X⁶ is CH₂.

[0161] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein X¹ is CH2; X² is O, NH, or CH₂; X³ is CH₂; X⁴ is CHR^4a; X⁵ is O; X⁶ is CH₂; and R⁹ is H.

[0162] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein ring A is heterocycloalkyl having 4 to 6 ring members with at least 1 nitrogen atom ring vertex, and 0 to 2 additional heteroatoms as ring vertices, wherein each additional heteroatom is independently N, O, or S.

[0163] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein ring A is heterocycloalkyl having 4 to 6 ring members with at least 1 nitrogen atom ring vertex, and 0 to 1 additional heteroatoms as ring vertices, wherein each additional heteroatom is independently N, O, or S.

[0164] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein ring A is heterocycloalkyl having 5 to 7 ring members with at least 1 nitrogen atom and 0 to 1 additional heteroatom as ring vertices, wherein the additional heteroatom is N, O, or S. In some embodiments, ring A is heterocycloalkyl having 5 to 7 ring members with at least 1 nitrogen atom and 0 to 1 additional heteroatom as ring vertices, wherein the additional heteroatom is N or O. In some embodiments, ring A is heterocycloalkyl having 5 to 7 ring members with at least 1 nitrogen atom and 0 to 1 oxygen atom as ring vertices.

[0165] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein ring A is heterocycloalkyl having 5 to 6 ring members with at least 1 nitrogen atom and 0 to 1 additional heteroatom as ring vertices, wherein each additional heteroatom is N, O, or S. In some embodiments, ring A is heterocycloalkyl having 5 to 6 ring members with at least 1 nitrogen atom and 0 to 1 additional heteroatom as ring vertices, wherein each additional heteroatom is N or O. In some embodiments, ring A is heterocycloalkyl having 5 to 6 ring members with at least 1 nitrogen atom and 0 to 1 oxygen atom as ring vertices.

[0166] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein ring A is heterocycloalkyl having 6 ring members with at least 1 nitrogen atom and 0 to 1 additional heteroatom as ring vertices, wherein each additional heteroatom is N, O, or S. In some embodiments, ring A is heterocycloalkyl having 6 ring members with at least 1 nitrogen atom and 0 to 1 additional heteroatom as ring vertices, wherein each additional heteroatom is N or O. In some embodiments, ring A is heterocycloalkyl having 6 ring members with at least 1 nitrogen atom and 0 to 1 oxygen atom as ring vertices.

[0167] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein ring A is pyrrolidinyl, piperidinyl, piperazinyl, or morpholinyl.

[0168] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein ring A is pyrrolidinyl, piperidinyl, piperazinyl, morpholinyl, or oxazepanyl.

[0169] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein ring A is piperidinyl, piperazinyl, or morpholinyl.

[0170] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein ring A is piperidinyl, substituted with 1 or 2 R⁷. [0171] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein ring A is piperazinyl, substituted with 1 or 2 R⁷.

[0172] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein ring A is morpholinyl, substituted with 1 or 2 R⁷.

[0173] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein, when ring C is present (i.e., formed by one R⁷ attached to ring A and one R⁸ attached to ring B, as defined herein), ring A is piperidinyl, piperazinyl, or morpholinyl, each of which is independently substituted with 0, 1, or 2 R⁷. In some embodiments, when ring C is present, ring A is piperidinyl substituted with 0, 1, or 2 R⁷. In some embodiments, when ring C is present, ring A is piperazinyl substituted with 0, 1, or 2 R⁷. In some embodiments, when ring C is present, ring A is morpholinyl substituted with 0, 1, or 2 R⁷.

[0174] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (la) or a subembodiment thereof, wherein ring A is piperidinyl, piperazinyl, or morpholinyl, each of which is independently substituted with 0, 1, or 2 R⁷. In some embodiments of Formula (la) or any one of the embodiments thereof, ring A is piperidinyl substituted with 0, 1, or 2 R⁷. In some embodiments of Formula (la) or any one of the embodiments thereof, ring A is piperazinyl substituted with 0, 1, or 2 R⁷. In some embodiments of Formula (la) or any one of the embodiments thereof, ring A is morpholinyl substituted with 0, 1, or 2 R⁷.

[0175] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein each R⁷ is independently Ci-6 alkyl, Ci-6 haloalkyl, halo, Ci-6 alkoxy, or Ci-6 haloalkoxy.

[0176] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein each R⁷ is independently C1.4 alkyl, Ci-4 haloalkyl, or halo.

[0177] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein each R⁷ is independently Ci-4 alkyl, halo, or Ci-4 alkoxy. In some embodiments, each R⁷ is independently Ci-4 alkyl, halo, OH, or Ci-4 alkoxy.

[0178] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein each R⁷ is independently methyl, ethyl, fluoro, chloro, bromo, fluoromethyl, difluoromethyl, or trifluoromethyl.

[0179] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein each R⁷ is independently methyl, ethyl, fluoro, chloro, bromo, methoxy, or ethoxy.

[0180] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein each R⁷ is independently methyl, fluoro, or methoxy.

[0181] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein each R⁷ is independently methyl or fluoro.

[0182] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein each R⁷ is independently methyl, fluoro, OH, or methoxy.

[0183] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein each R⁷ is independently methyl or methoxy.

[0184] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein each R⁵ is independently methyl or methoxy.

[0185] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein each R⁷ is methyl.

[0186] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein each R⁷ is fluoro. [0187] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein each R⁷ is OH.

[0188] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein each R⁷ is methoxy.

[0189] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein, when ring C is present (i.e., formed by one R⁷ attached to ring A and one R⁸ attached to ring B, as defined herein), ring A is piperidinyl, piperazinyl, or morpholinyl, each of which is independently substituted with 0, 1, or 2 R⁷; and each R⁷ is independently methyl, fluoro, or methoxy.

[0190] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein, when ring C is present, ring A is piperidinyl substituted with 0 R⁷. In some embodiments of Formula (I) or any one of the embodiments thereof, when ring C is present, ring A is piperidinyl substituted with one R⁷; and R⁷ is methyl, fluoro, or methoxy. In some embodiments of Formula (I) or any one of the embodiments thereof, when ring C is present, ring A is piperidinyl substituted with one R⁷; and R⁷ is methyl. In some embodiments of Formula (I) or any one of the embodiments thereof, when ring C is present, ring A is piperidinyl substituted with one R⁷; and R⁷ is fluoro. In some embodiments of Formula (I) or any one of the embodiments thereof, when ring C is present, ring A is piperidinyl substituted with one R⁷; and R⁷ is methoxy.

[0191] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein, when ring C is present, ring A is morpholinyl substituted with 0 R⁷. In some embodiments of Formula (I) or any one of the embodiments thereof, when ring C is present, ring A is morpholinyl substituted with one R⁷; and R⁷ is methyl or fluoro. In some embodiments of Formula (I) or any one of the embodiments thereof, when ring C is present, ring A is morpholinyl substituted with one R⁷; and R⁷ is methyl.

[0192] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, having Formula (la): wherein, ring B is phenyl or heteroaryl having 5 to 6 ring members with 1 to 3 heteroatom ring vertices, wherein each heteroatom is independently N, O, or S; p is 0, 1 or 2; q is 0, 1, or 2; and ring C is fused to (a) two adjacent ring vertices of ring A and (b) two adjacent ring vertices of ring B, and ring C is C4-7 cycloalkyl or heterocycloalkyl having 4 to 7 ring members with 1 to 3 heteroatom ring vertices, wherein each heteroatom is independently N, O, S, S(O), or S(O)₂.

[0193] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or (la), or a subembodiment thereof, wherein: X¹ is C(R^laR^lb);

X² is C(R^2aR^2b), O, or NR²; R² is H or Cu alkyl;

X³ is C(R^3aR^3b);

X⁴ is C(R^4aR^4b); X⁵ is O; X⁶ is C(R^6aR^6b);

R^la, R^lb, R^2a, R^2b, R^3a, R^3b, R^4a, R^4b, R^6a, and R^6b are each independently H or C1-4 alkyl; ring A is heterocycloalkyl having 5 to 7 ring members with at least 1 nitrogen atom and 0 to 1 additional heteroatom as ring vertices, wherein each additional heteroatom is N or O; ring B is phenyl or heteroaryl having 5 to 6 ring members with 1 to 3 heteroatom ring vertices, wherein each heteroatom is independently N, O, or S; ring C is C5-7 cycloalkyl or heterocycloalkyl having 5 to 7 ring members with 1 to 3 heteroatom ring vertices, wherein each heteroatom is independently N, O, or S, wherein ring C is substituted with 0, 1, or 2 R^7a; p is 0 or 1; q is 1;

R⁷ is C1-4 alkyl, halo, or C1-4 alkoxy;

R⁸ is C1-4 alkyl, C1-4 haloalkyl, halo, CN, C1-4 alkoxy, C1-4 haloalkoxy, or C3-6 cycloalkyl; and R⁹ is H. [0194] Unless specifically indicated otherwise, embodiments or subembodiments related to Formula (la) are applicable to any one of Formulae (Ial-1), (Ial-2), (Ia2-1), (Ia2-2), (II), (Ha), (Ha-1), and (Ha-2).

[0195] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (la), or a subembodiment thereof, wherein: ring A is heterocycloalkyl having 5 to 7 ring members with at least 1 nitrogen atom and 0 to 1 additional heteroatom as ring vertices, wherein each additional heteroatom is independently N or O; ring B is phenyl or heteroaryl having 6 ring members with 1 to 2 nitrogen atom ring vertices; and ring C is C5-6 cycloalkyl or heterocycloalkyl having 5 to 7 ring members with 1 heteroatom ring vertex, wherein the heteroatom is N or O.

[0196] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (la), or a subembodiment thereof, wherein ring A is pyrrolidinyl, piperidinyl, piperazinyl, morpholinyl, or oxazepanyl. In some embodiments, ring A is piperidinyl, piperazinyl, or morpholinyl.

[0197] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (la), or a subembodiment thereof, wherein ring B is phenyl, pyridyl, pyrazinyl, pyrimidinyl, or pyridazinyl. In some embodiments, ring B is phenyl or pyridyl.

[0198] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (la) or a subembodiment thereof, wherein ring A is piperidinyl, piperazinyl, or morpholinyl, each of which is independently substituted with 0, 1, or 2 R⁷; and each R⁷ is independently methyl, fluoro, OH, or methoxy. In some embodiments of Formula (la) or any one of the embodiments thereof, ring A is piperidinyl, piperazinyl, or morpholinyl, each of which is independently substituted with 0, 1, or 2 R⁷; and each R⁷ is independently methyl, fluoro, or methoxy.

[0199] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (la) or a subembodiment thereof, wherein ring A is piperidinyl substituted with 0 R⁷. In some embodiments of Formula (la) or any one of the embodiments thereof, ring A is piperidinyl substituted with one R⁷; and R⁷ is methyl, fluoro, OH, or methoxy. In some embodiments of Formula (la) or any one of the embodiments thereof, ring A is piperidinyl substituted with one R⁷; and R⁷ is methyl, fluoro, or methoxy. In some embodiments of Formula (la) or any one of the embodiments thereof, ring A is piperidinyl substituted with one R⁷; and R⁷ is methyl. In some embodiments of Formula (la) or any one of the embodiments thereof, ring A is piperidinyl substituted with one R⁷; and R⁷ is fluoro. In some embodiments of Formula (la) or any one of the embodiments thereof, ring A is piperidinyl substituted with one R⁷; and R⁷ is OH. In some embodiments of Formula (la) or any one of the embodiments thereof, ring A is piperidinyl substituted with one R⁷; and R⁷ is methoxy. In some embodiments of Formula (la) or any one of the embodiments thereof, ring A is piperidinyl substituted with one R⁷; and R⁷ is OH.

[0200] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (la) or a subembodiment thereof, wherein ring A is morph olinyl substituted with 0 R⁷. In some embodiments of Formula (la) or any one of the embodiments thereof, ring A is morpholinyl substituted with one R⁷; and R⁷ is methyl or fluoro. In some embodiments of Formula (la) or any one of the embodiments thereof, ring A is morpholinyl substituted with one R⁷; and R⁷ is methyl.

[0201] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (la) or a subembodiment thereof, wherein ring A is piperidinyl substituted with 2 vicinal R⁷; and each R⁷ is independently methyl, fluoro, OH, or methoxy. In some embodiments of Formula (la) or any one of the embodiments thereof, ring A is piperidinyl substituted with two vicinal R⁷; one R⁷ is methyl; and the other R⁷ is fluoro. In some embodiments of Formula (la) or any one of the embodiments thereof, ring A is piperidinyl substituted with two vicinal R⁷; one R⁷ is methyl; and the other R⁷ is OH. In some embodiments of Formula (la) or any one of the embodiments thereof, ring A is piperidinyl substituted with two vicinal R⁷; one R⁷ is methyl; and the other R⁷ is methoxy.

[0202] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (la) or a subembodiment thereof, wherein ring A is piperidinyl substituted with 2 geminal R⁷; and each R⁷ is independently methyl, fluoro, OH, or methoxy. In some embodiments of Formula (la) or any one of the embodiments thereof, ring A is piperidinyl substituted with two geminal R⁷; one R⁷ is methyl; and the other R⁷ is fluoro. In some embodiments of Formula (la) or any one of the embodiments thereof, ring A is piperidinyl substituted with two geminal R⁷; one R⁷ is methyl; and the other R⁷ is OH. In some embodiments of Formula (la) or any one of the embodiments thereof, ring A is piperidinyl substituted with two geminal R⁷; one R⁷ is methyl; and the other R⁷ is methoxy. In some embodiments of Formula (la) or any one of the embodiments thereof, ring A is piperidinyl substituted with two geminal R⁷; and each R⁷ is methyl. In some embodiments of Formula (la) or any one of the embodiments thereof, ring A is piperidinyl substituted with two geminal R⁷; and each R⁷ is fluoro.

[0203] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (la) or a subembodiment thereof, wherein ring A is piperazinyl, substituted with 2 vicinal R⁷ or 2 geminal R⁷, wherein each R⁷ is any one of embodiments described herein.

[0204] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (la) or a subembodiment thereof, wherein ring A is morpholinyl substituted with 2 vicinal R⁷ or 2 geminal R⁷, wherein each R⁷ is any one of embodiments described herein.

[0205] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, having Formula (Ial-1): wherein:

X^a is O, NH, CH₂, or CHR⁷; p is 0 or 1; q is 0, 1, or 2; and ring C is C4-7 cycloalkyl or heterocycloalkyl having 4 to 7 ring members with 1 to 3 heteroatom ring vertices, wherein each heteroatom is independently N, O, S, S(O), or S(O)₂. [0206] In some embodiments, In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, having Formula (Ial-2): or the pharmaceutically acceptable salt thereof, wherein, X^a is O, NH, CH₂, or CHR⁷; p is 0 or 1; q is 0, 1, or 2; and ring C is C4-7 cycloalkyl or heterocycloalkyl having 4 to 7 ring members with 1 to 3 heteroatom ring vertices, wherein each heteroatom is independently N, O, S, S(O), or S(O)₂.

[0207] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, having Formula (Ial-1): wherein,

X^a is O, CH₂, or CHR⁷; p is 0 or 1; q is 0, 1, or 2; and ring C is C4-7 cycloalkyl or heterocycloalkyl having 4 to 7 ring members with 1 to 3 heteroatom ring vertices, wherein each heteroatom is independently N, O, S, S(O), or S(O)₂. [0208] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein ring C is C4-7 cycloalkyl substituted with 0, 1, 2, or 3 R^7a.

[0209] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein ring C is C4-6 cycloalkyl substituted with 0, 1, 2, or 3 R^7a.

[0210] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein ring C is C5-6 cycloalkyl substituted with 0, 1 , or 2 R^7a.

[0211] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein ring C is Ce cycloalkyl substituted with 0, 1, or 2 R^7a.

[0212] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein ring C is C5 cycloalkyl substituted with 0, 1, or 2 R^7a.

[0213] With reference to any one of Formulae (I), (la), (Ial-1), and (Ial-2), or any one of embodiments thereof, in some embodiments, ring C is C5-6 cycloalkyl substituted with 0, 1, or 2 R^7a. In some embodiments, ring C is C6 cycloalkyl substituted with 0, 1, or 2 R^7a. In some embodiments, ring C is C5 cycloalkyl substituted with 0, 1, or 2 R^7a.

[0214] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein ring C is heterocycloalkyl having 4 to 7 ring members with 1 to 3 heteroatom ring vertices, wherein each heteroatom is independently N, O, S, S(O), or S(O)2, wherein ring C is substituted with 0, 1, 2, or 3 R^7a.

[0215] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein ring C is heterocycloalkyl having 4 to 6 ring members with 1 to 2 heteroatom ring vertices, wherein each heteroatom is independently N, O, S, S(O), or S(O)2, wherein ring C is substituted with 0, 1, 2, or 3 R^7a. [0216] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein ring C is heterocycloalkyl having 5 to 6 ring members with 1 to 2 heteroatom ring vertices, wherein each heteroatom is independently N, O, or S, S(O), or S(O)2, wherein ring C is substituted with 0, 1, 2, or 3 R^7a.

[0217] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein ring C is heterocycloalkyl having 5 ring members with 1 to 2 heteroatom ring vertices, wherein each heteroatom is independently N, O, or S, wherein ring C is substituted with 0, 1, or 2 R^7a.

[0218] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein ring C is heterocycloalkyl having 6 ring members with 1 to 2 heteroatom ring vertices, wherein each heteroatom is independently N, O, or S, wherein ring C is substituted with 0, 1, 2, or 3 R^7a.

[0219] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein ring C is heterocycloalkyl having 6 ring members with 1 to 2 heteroatom ring vertices, wherein each heteroatom is independently N, O, S, S(O), or S(O)2, wherein ring C is substituted with 0, 1, 2, or 3 R^7a.

[0220] With reference to any one of Formulae (I), (la), (Ial-1), and (Ial-2), or any one of embodiments thereof, in some embodiments, ring C is heterocycloalkyl having 5 to 6 ring members with 1 to 2 heteroatom ring vertices, wherein each heteroatom is independently N, O, or S, wherein ring C is substituted with 0, 1, or 2 R^7a. In some embodiments, ring C is heterocycloalkyl having 5 ring members with 1 to 2 heteroatom ring vertices, wherein each heteroatom is independently N, O, or S, wherein ring C is substituted with 0, 1, or 2 R^7a. In some embodiments, ring C is heterocycloalkyl having 6 ring members with 1 to 2 heteroatom ring vertices, wherein each heteroatom is independently N, O, or S, wherein ring C is substituted with 0, 1, or 2 R^7a.

[0221] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (la) or a subembodiment thereof, wherein ring C is C5-6 cycloalkyl or heterocycloalkyl having 5 to 7 ring members with 1 heteroatom ring vertex, wherein the heteroatom is N or O. In some embodiments of Formula (la) or any one of the embodiments thereof, ring C is C5-6 cycloalkyl. In some embodiments of Formula (la) or any one of the embodiments thereof, ring C is heterocycloalkyl having 5 to 7 ring members with 1 heteroatom ring vertex, wherein the heteroatom is N or O.

[0222] In some embodiments of Formula (la) or any one of the embodiments thereof, ring C is C5-6 cycloalkyl, tetrahydrofuranyl, tetrahydropyranyl, or oxepanyl. In some embodiments of Formula (la) or any one of the embodiments thereof, ring C is C5-6 cycloalkyl, tetrahydrofuranyl, or tetrahydropyranyl.

[0223] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein ring C is tetrahydropyranyl substituted with 0, 1, or 2 R^7a.

[0224] In some embodiments of Formula (la) or any one of the embodiments thereof, ring C is tetrahydrofuranyl, tetrahydropyranyl, or oxepanyl, each of which is independently substituted with 0 or 1 R^7a. In some embodiments, ring C is tetrahydrofuranyl substituted with 0 or 1 R^7a. In some embodiments, ring C is tetrahydropyranyl substituted with 0 or 1 R^7a. In some embodiments, ring C is oxepanyl substituted with 0 or 1 R^7a.

[0225] With reference to any one of Formulae (I), (la), (Ial-1), and (Ial-2), or any one of embodiments thereof, in some embodiments, ring C is tetrahydropyranyl substituted with 0, 1, or 2 R^7a. In some embodiments, ring C is tetrahydropyranyl substituted with 0 or 1 R^7a. In some embodiments, ring C is tetrahydropyranyl substituted with 0 R^7a.

[0226] With reference to any one of Formulae (I), (la), (Ial-1), and (Ial-2), or any one of embodiments thereof, in some embodiments, ring C is tetrahydrofuranyl substituted with 0 or 1 R^7a. In some embodiments, ring C is tetrahydrofuranyl substituted with 0 R^7a.

[0227] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, having Formula (Ia2-1): wherein,

X^a is absent, O, CH₂, or CHR⁷;

X^7a is absent, O or CH₂, or CHR^7a;

X^7b is absent, O or CH₂, or CHR^7a; p is 0, 1 or 2; and q is 0, 1, or 2.

[0228] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein

X^a is O, CH₂, or CHR⁷;

X^7a is O or CH₂, or CHR^7a;

X^7b is O or CH₂, or CHR^7a; p is 0, 1 or 2; and q is 0, 1, or 2.

[0229] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, having Formula (Ia2-1): wherein,

X^a is O, NH, CH₂, or CHR⁷;

X^7a is absent, O, CH₂, or CHR^7a;

X^7b is absent, O, CH₂, or CHR^7a; p is 0, 1, or 2; and q is 0, 1, or 2, provided that X^7a and X^7b are not each O.

[0230] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, having Formula (Ia2-2):

wherein,

X^a is O, NH, CH₂, or CHR⁷;

X^7a is absent, O, CH₂, or CHR^7a;

[0231] In some embodiments of Formula (Ia2-1) or (Ia2-2), or any one of the embodiments thereof, X^7a and X^7b are not each absent.

[0232] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (Ia2-1) or (Ia2-2) or a subembodiment thereof, wherein X^7a is O; and X^7b is CH₂.

[0233] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (Ia2-1) or (Ia2-2) or a subembodiment thereof, wherein X^7a is CH₂; and X⁷¹* is O.

[0234] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (Ia2-1) or (Ia2-2) or a subembodiment thereof, wherein X^7a is CH₂; and X⁷’’ is CH₂.

[0235] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (Ia2-1) or (Ia2-2) or a subembodiment thereof, wherein X^7a is absent; and X⁷⁶ is CH₂.

[0236] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (Ia2-1) or (Ia2-2) or a subembodiment thereof, wherein X^7a is absent; and X⁷¹¹ is O. [0237] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein each R^7a is independently C1.4 alkyl, halo, or C1.4 haloalkyl.

[0238] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein each R^7a is independently methyl, ethyl, fluoro, chloro, bromo, fluoromethyl, difluoromethyl, or trifluoromethyl.

[0239] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein each R^7a is independently methyl, fluoro, chloro, or trifluoromethyl

[0240] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein two R^7a groups attached to the same carbon atom combine to form oxo.

[0241] In some embodiments of Formula (Ia2- 1 ) or (Ia2-2), or any one of the embodiments thereof, X^7a is O, CH2, or CHR^7a; and X^7b is O, CH2, or CHR^7a, provided that X^7a and X^7b are not each O. In some embodiments, R^7a is C1-4 alkyl. In some embodiments, R^7a is methyl.

[0242] In some embodiments of Formula (Ia2-1) or (Ia2-2), or any one of the embodiments thereof, X^7a is O, and X^7b is CH2. In some embodiments, X^7a is CH2; and X^7b is O. In some embodiments, X^7a is CH2, and X^7b is CH2. In some embodiments, X^7a is O; and X^7b is CH(CH3). In some embodiments, X^7a is CH(CH3), and X^7b is O. In some embodiments, X^7a is CH₂ and X^7b is CH(CH₃); or X^7a is CH(CH₃) and X^7b is CH₂.

[0243] In some embodiments of Formula (Ia2-1) or (Ia2-2), or any one of the embodiments thereof, X^7a is absent; and X^7b is O.

[0244] In some embodiments of Formula (Ia2-1) or (Ia2-2), or any one of the embodiments thereof, X^7a is absent; and X^7b is CH2.

[0245] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein each R⁸ is independently C1-6 alkyl, C1-6 haloalkyl, halo, C1-6 alkoxy, or C1-6 haloalkoxy. [0246] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein each R⁸ is independently Ci-6 alkyl, Ci-6 haloalkyl, or halo.

[0247] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein each R⁸ is independently methyl, ethyl, fluoro, chloro, bromo, fluoromethyl, difluoromethyl, or trifluoromethyl.

[0248] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein each R⁸ is independently bromo or trifluoromethyl.

[0249] With reference to any one of Formulae (I), (la), (Ial-1), (Ial-2), (Ia2-1), and (Ia2-2), in some embodiments, each R⁸ is independently Ci-6 alkyl, Ci-6 haloalkyl, halo, CN, Ci-6 alkoxy, Ci-6 haloalkoxy, or C3-6 cycloalkyl. In some embodiments, each R⁸ is independently C1-6 alkyl, Ci-6 haloalkyl, halo, C1-6 haloalkoxy, or C3-6 cycloalkyl.

[0250] With reference to any one of Formulae (I), (la), (Ial-1), (Ial-2), (Ia2-1), and (Ia2-2), in some embodiments, q is 1; and R⁸ is Ci-6 alkyl, Ci-6 haloalkyl, halo, CN, Ci-6 alkoxy, Ci-6 haloalkoxy, or C3-6 cycloalkyl. In some embodiments, q is 1; and R⁸ is Ci-6 alkyl, Ci-6 haloalkyl, halo, Ci-6 alkoxy, or C 1-6 haloalkoxy.

[0251] With reference to any one of Formulae (I), (la), (Ial-1), (Ial-2), (Ia2-1), and (Ia2-2), in some embodiments, q is 1 ; and R⁸ is chloro, CN, isopropyl, cyclopropyl, fluoromethyl, difluoromethyl, trifluoromethyl, fluoromethyl-O-, difluoromethyl-O-, or trifluoromethyl- O- . In some embodiments, q is 1; and R⁸ is chloro, isopropyl, cyclopropyl, trifluoromethyl, or difluoromethyl-O-. In some embodiments, q is 1; and R⁸ is chloro, trifluoromethyl, or difluoromethyl-O-. In some embodiments, q is 1 ; and R⁸ is chloro. In some embodiments, q is 1 ; and R⁸ is trifluoromethyl. In some embodiments, q is 1 ; and R⁸ is difluoromethyl-O-. In some embodiments, q is 1; and R⁸is CN.

[0252] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I), (la), or a subembodiment thereof, wherein each R⁸ is independently Ci-6 alkyl, Ci-6 haloalkyl, halo, OH, Ci-6 alkoxy, Ci-6 haloalkoxy, CN, C2-6 alkynyl, -O-C2-6 alkynyl, C3-6 cycloalkyl, or -O-C3-6 cycloalkyl, wherein the C3-6 cycloalkyl and -O-C3-6 cycloalkyl are each independently substituted with 0 or 1 CN. [0253] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I), (la), or a subembodiment thereof, wherein each R⁸ is independently chloro, CN, isopropyl, methoxy, fluoromethyl, difluoromethyl, trifluoromethyl, fluoromethyl-O-, difluoromethyl-O-, trifluoromethyl-O-, cyclopropyl, NC-cyclopropyl-, cyclopropyl-O-, HC=C-, or HC=C-CH2-O-

[0254] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I), (la), or a subembodiment thereof, wherein q is 1; and R⁸ is Ci-6 alkyl, Ci-6 haloalkyl, halo, OH, Ci-6 alkoxy, Ci-6 haloalkoxy, CN, C2-6 alkynyl, -O-C2-6 alkynyl, C3-6 cycloalkyl, or -O-C3-6 cycloalkyl, wherein the C3-6 cycloalkyl and -O- C3-6 cycloalkyl are each independently substituted with 0 or 1 CN.

[0255] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I), (la), or a subembodiment thereof, wherein q is 1; and R⁸ is chloro, CN, isopropyl, methoxy, fluoromethyl, difluoromethyl, trifluoromethyl, fluoromethyl-O-, difluoromethyl-O-, trifluoromethyl-O-, cyclopropyl, NC-cyclopropyl-, cyclopropyl-O-, HC=C-, or HC=C-CH2-O-.

[0256] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I), (la), or a subembodiment thereof, wherein q is 1; and R⁸ is chloro, trifluoromethyl, or difluoromethyl-O-.

[0257] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I), (la), or a subembodiment thereof, wherein q is 2; and each R⁸ is independently fluoro, chloro, methoxy, trifluoromethyl, or difluoromethyl-O-.

[0258] In some embodiments of Formula (I), or any one of the embodiments thereof, the moiety has the formula:

wherein:

X^a is O, NH, CH₂, or CHR⁷;

X^7a is O, CH₂, or CHR^7a;

X^7b is O, CH₂, or CHR^7a; each R^7a is independently C1-4 alkyl; each R⁷ is independently F, C1-4 alkyl, or C1-4 alkoxy; and

R⁸ is C1-4 alkyl, C1-4 haloalkyl, halo, CN, C1-4 alkoxy, C1-4 haloalkoxy, or C3-5 cycloalkyl, provided that X^7a and X^7b are not each O.

[0259] In some embodiments of the above moieties 1 to 12, X^a is O, NH, CH₂, CHF, C(CH₃), or C(OCH₃); X^7a is O, CH₂, or CH(CH₃); X^7b is O or CH₂; R⁷ is F, CH₃, or OCH₃; R⁸ is chloro, CN, isopropyl, cyclopropyl, difluoromethyl, trifluoromethyl, difluoromethyl-O- , or trifluoromethyl-O-, provided that X^7aand X^7b are not each O. In some embodiments of moieties 1 to 4, X^a is CH₂; X^7a is CH₂; X^7b is O; and R⁸ is chloro, CN, isopropyl, cyclopropyl, difluoromethyl, trifluoromethyl, difluoromethyl-O-, or trifluoromethyl-O-. In some embodiments of moieties 1 to 4, X^a is O; X^7a is O; X^7b is CH₂; and R⁸ is chloro, CN, isopropyl, cyclopropyl, difluoromethyl, trifluoromethyl, difluoromethyl-O-, or trifluoromethyl-O-.

[0260] In some embodiments of the above moieties 1 to 12, X^a is O, CH₂, or CHF; X^7a is O, CH₂, or CH(CH₃); X^7b is O or CH₂; R⁷ is CH₃; R⁸ is chloro, isopropyl, cyclopropyl, trifluoromethyl, or difluoromethyl-O-, provided that X^7a and X⁷¹¹ are not each O. In some embodiments of moieties 1 to 4, X^a is CFb; X^7a is CH2; X^7b is O; and R⁸ is chloro, isopropyl, cyclopropyl, trifluoromethyl, or difhioromethyl-O- In some embodiments of moieties 1 to 4, X^a is O; X^7a is O; X⁷¹¹ is CH2; and R⁸ is chloro, isopropyl, cyclopropyl, trifluoromethyl, or difluoromethyl-O-.

[0261] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein the moiety

[0262] In some embodiments of Formula (I), or any one of the embodiment thereof, the moiety has any one of formulae according to the Amine intermediates in

Examples, wherein the nitrogen at the ring A is attached to the remainder of the molecule.

[0263] With reference to any one of Formulae (Ial-1), (Ial-2), (Ia2-1), and (Ia2-2), or any one of the embodiments thereof, in some embodiments, X¹ is C(R^laR^lb); X² is C(R^2aR^2b), O, or NR²; X³ is C(R^3aR^3b); X⁴ is C(R^4aR^4b); X⁵ is O; X⁶ is C(R^6aR^6b); R² is H or Ci-4 alkyl; R^la, R^lb, R^2a, R^2b, R^3a, R^3b, R^4a, R^4b, R^6a, and R^6b are each independently H or CM alkyl; and R⁹ is H.

[0264] With reference to any one of Formulae (I), (la), (Ial-1), (Ial-2), (Ia2-1), and (Ia2-2), or any one of the embodiments thereof, in some embodiments, the moiety or NR²; and R^4a and R^6a are each independently H or C1-4 alkyl. In some embodiments, X² is O, NH, or CH2; R^4a is H or C1-4 alkyl; and R^6a is H. In some embodiments, X² is O, NH, or CH2; R^4a and R^6a are each independently H or methyl. In some embodiments, X² is O, NH, or CH2; and R^4a and R^6a are each H. In some embodiments, X² is O, NH, or CH2; R^4a is methyl; and R^6a is H. In some embodiments, X² is O, NH, or CH2; R^4a is H; and R^6a is methyl.

[0265] With reference to any one of Formulae (I), (la), (Ial-1), (Ial-2), (Ia2-1), and (Ia2-2), or any one of the embodiments thereof, in some embodiments, the moiety each defined and described herein. In some embodiments, X2 is O, NH, or CH2; and R^4a is H or C1-4 alkyl. In some embodiments, X2 is O; and R^4a is H. In some embodiments, X2 is O; and R^4a is methyl. In some embodiments, X2 is NH; and R^4a is H. In some embodiments, X2 is NH; and R^4a is methyl. In some embodiments, X2 is CH2; and R^4a is H. In some embodiments, X2 is CH2; and R^4a is methyl.

[0266] With reference to any one of Formulae (I), (la), (Ial-1), (Ial-2), (Ia2-1), and (Ia2-2), or any one of the embodiments thereof, in some embodiments, the moiety alkyl. In some embodiments, R^4a is H. In some embodiments, R^4a is methyl.

[0267] With reference to any one of Formulae (I), (la), (Ial-1), (Ial-2), (Ia2-1), and (Ia2-2), or any one of the embodiments thereof, in some embodiments, the moiety wherein R^4a is H or Ci-4 alkyl. In some embodiments, R^4a is H. In some embodiments, R^4a is methyl.

[0268] With reference to any one of Formulae (I), (la), (Ial-1), (Ial-2), (Ia2-1), and (Ia2-2), or any one of the embodiments thereof, in some embodiments, the moiety alkyl. In some embodiments, R^4a is H. In some embodiments, R^4a is methyl.

[0269] With reference to any one of Formulae (I), (la), (Ial-1), (Ial-2), (Ia2-1), and (Ia2-2), or any one of the embodiments thereof, in some embodiments, the moiety has one of the formulae selected from:

[0270] In some embodiments, the compound is represented by Formula (II): or a pharmaceutically acceptable salt thereof, wherein: wherein:

X^a is O, NH, NR⁷, CH₂, CHR⁷, or C(R⁷)₂;

X^7a is absent, 0, CH₂, or CHR^7a;

X^7b is absent, O, CH₂, or CHR^7a, provided that X^7a and X^7b are not each absent or O; and a total number of R⁷ groups is no more than 2; and p, q, ring B, X², R^3a, R^4a, R^6a, R⁷, and R⁸ are each defined in Formula (I) or (la), and described in any one of the embodiments thereof.

[0271] Unless specifically indicated otherwise, embodiments or subembodiments related to Formula (II) are applicable to any one of Formulae (Da), (IIa-1), and (IIa-2).

[0272] In some embodiments of Formula (II), R^3a and R^6a are each H.

[0273] In some embodiments, the compound is represented by Formula (Ila): wherein: ring B is phenyl, pyridyl, pyrazinyl, pyrimidinyl, or pyridazinyl;

X^a is O, NH, NR⁷, CH₂, CHR⁷, or C(R⁷)₂;

X^7a is absent, O, CH₂, or CHR^7a; and

X^7b is absent, O, CH₂, or CHR^7a, provided that X^7a and X^7b are not each absent or O; and a total number of R⁷ groups is no more than 2.

[0274] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (II), (Ila), or a subembodiment thereof, wherein ring B is phenyl, pyridyl, pyrazinyl, pyrimidinyl, or pyridazinyl. In some embodiments, ring B is phenyl. In some embodiments, ring B is pyridyl. In some embodiments, ring B is pyrazinyl. In some embodiments, ring B is pyrimidinyl. In some embodiments, ring B is pyridazinyl.

[0275] In some embodiments, the compound is represented by Formula (IIa-1): wherein:

X^a is O, NH, N(CI-₄ alkyl), CH₂, CHR⁷, or C(R⁷)₂;

X^7a is absent, O, CH₂, or CHR^7a; and

[0276] In some embodiments, the compound is represented by Formula (IIa-2): wherein:

X^a is O, NH, N(CI-₄ alkyl), CH₂, CHR⁷, or C(R⁷)₂;

X^7a is absent, O, CH₂, or CHR^7a; and

[0277] In some embodiments of Formula (II), (Ila), (IIa-1), or (IIa-2), or a subembodiment thereof, X² is O.

[0278] In some embodiments of Formula (II), (Ila), (IIa-1), or (IIa-2), or a subembodiment thereof, X² is NH.

[0279] In some embodiments of Formula (II), (Ila), (IIa-1), or (IIa-2), or a subembodiment thereof, X² is CH₂. [0280] In some embodiments of Formula (II), (Ila), (IIa-1), or (IIa-2), or a subembodiment thereof, X^a is CH₂, CHR⁷, or C(R⁷)₂.

[0281] In some embodiments of Formula (II), (Ila), (IIa-1), or (IIa-2), or a subembodiment thereof, X^a is O.

[0282] In some embodiments of Formula (II), (Ila), (IIa-1), or (IIa-2), or a subembodiment thereof, X^a is NH.

[0283] In some embodiments of Formula (II), (Ila), (IIa-1), or (IIa-2), or a subembodiment thereof, X^a is CH₂.

[0284] In some embodiments of Formula (II), (Ila), (IIa-1), or (IIa-2), or a subembodiment thereof, X^a is O, NH, CH₂, or CHR⁷; X^7a is O, CH₂, or CHR^7a; X^7b is O, CH₂, or CHR^7a; and p is 0 or 1.

[0285] In some embodiments of Formula (II), (Ila), (IIa-1), or (IIa-2), or a subembodiment thereof, X^a is O, NH, or CH₂; X^7a is O, CH₂, or CHR^7a; X^7b is O, CH₂, or CHR^7a; and p is 0, 1, or 2.

[0286] In some embodiments of Formula (II), (Ila), (IIa-1), or (IIa-2), or a subembodiment thereof, X^a is C(R⁷)₂; X^7a is O, CH₂, or CHR^7a; X^7b is O, CH₂, or CHR^7a; and p is 0.

[0287] In some embodiments of Formula (II), (Ila), (IIa-1), or (IIa-2), or a subembodiment thereof, X^7a is O and X^7b is CH₂; X^7a is CH₂ and X^7b is O; X^7a is CH₂ and X^7b is CH₂; X^7a is O and X^7b is CH(CH₃); X^7a is CH(CH₃) and X^7b is O; X^7a is CH₂ and X^7b is CH(CH₃); X^7a is CH(CH₃) and X^7b is CH₂; X^7a is absent and X^7b is CH₂; or X^7a is absent and X^7b is O. In some embodiments, X^7a is O and X^7b is CH₂. In some embodiments, X^7a is CH₂ and X^7b is O. In some embodiments, X^7a is CH₂ and X⁷¹¹ is CH₂. In some embodiments, X^7a is O and X is CH(CH₃). In some embodiments, X^7a is CH(CH₃) and X^7b is O. In some embodiments, X^7a is CH₂ and X^7b is CH(CH₃). In some embodiments, X^7a is CH(CH₃) and X^7b is CH₂. In some embodiments, X^7a is absent and X^7b is CH₂. In some embodiments, X^7a is absent and X^7b is O.

[0288] In some embodiments of Formula (II), (Ila), (IIa-1), or (IIa-2), or a subembodiment thereof, each R⁷ is independently Ci-4 alkyl, halo, OH, or Ci-4 alkoxy. In some embodiments, each R⁷ is independently methyl, fluoro, OH, or methoxy. In some embodiments, each R⁷ is independently methyl, fluoro, or methoxy. [0289] In some embodiments of Formula (II), (Ila), (IIa-1), or (IIa-2), or a subembodiment thereof, each R⁸ is independently C1-6 alkyl, C1-6 haloalkyl, halo, OH, C1-6 alkoxy, C1-6 haloalkoxy, CN, C2-6 alkynyl, -O-C2-6 alkynyl, C3-6 cycloalkyl, or -O-C3-6 cycloalkyl, wherein the C3-6 cycloalkyl and -O-C3-6 cycloalkyl are each independently substituted with 0 or 1 CN.

[0290] In some embodiments of Formula (II), (Ila), (IIa-1), or (IIa-2), or a subembodiment thereof, each R⁸ is independently chloro, CN, isopropyl, methoxy, fluoromethyl, difluoromethyl, trifluoromethyl, fluoromethyl-O-, difluoromethyl-O-, trifluoromethyl-O-, cyclopropyl, NC-cyclopropyl-, cyclopropyl-O-, HC=C-, or HC=C-CH2-O-

[0291] In some embodiments of Formula (II), (Ila), (IIa-1), or (IIa-2), or a subembodiment thereof, q is 1; and R⁸ is C1-6 alkyl, C1-6 haloalkyl, halo, OH, C1-6 alkoxy, C1-6 haloalkoxy, CN, C2-6 alkynyl, -O-C2-6 alkynyl, C3-6 cycloalkyl, or -O-C3-6 cycloalkyl, wherein the C3-6 cycloalkyl and -O-C3-6 cycloalkyl are each independently substituted with 0 or 1 CN.

[0292] In some embodiments of Formula (II), (Ila), (IIa-1), or (IIa-2), or a subembodiment thereof, q is 1; and R⁸ is chloro, CN, isopropyl, methoxy, fluoromethyl, difluoromethyl, trifluoromethyl, fluoromethyl-O-, difluoromethyl-O-, trifluoromethyl-O-, cyclopropyl, NC-cyclopropyl-, cyclopropyl-O-, HC=C-, or HOC-CH2-O-. In some embodiments, q is 1; and R⁸ is chloro, trifluoromethyl, or difluoromethyl-O-. In some embodiments, q is 2; and each R⁸ is independently fluoro, chloro, methoxy, trifluoromethyl, or difluoromethyl-O-.

[0293] In some embodiments of Formula (la), the moiety formula:

wherein:

X^a is O, NH, CH₂, or CHR⁷;

X^7a is O, CH₂, or CHR^7a;

X^7b is O, CH₂, or CHR^7a; each R^7a is independently C1-4 alkyl; each R⁷ is independently F, OH, C1-4 alkyl, or C1-4 alkoxy; and

R⁸ is C1-4 alkyl, C1-4 haloalkyl, halo, CN, C1-4 alkoxy, C1-4 haloalkoxy, C₂ alkynyl, -O-C₂-4 alkynyl, C₃-6 cycloalkyl, or -O-C₃.6 cycloalkyl, wherein the C₃-6 cycloalkyl and -O- C₃-6 cycloalkyl are each independently unsubstituted or substituted with CN, provided that X^7a and X^7b are not each O.

[0294] In some embodiments of Formula (II), (Ila), or related Formula (IIa-1) or (IIa-2), the moiety any one of the above moieties 1 to 12.

[0295] In some embodiments of the above moieties 1 to 12, X^a is O, NH, CH2, CHF, C(CH₃), C(OH), or C(OCH₃); X^7a is O, CH₂, or CH(CH₃); X^7b is O or CH₂; R⁷ is F, CH₃, OH, or OCH₃; and R⁸ is chloro, CN, isopropyl, methoxy, fluoromethyl, difluoromethyl, trifluoromethyl, fluoromethyl-O-, difluoromethyl-O-, trifluoromethyl-O-, cyclopropyl, NC-cyclopropyl-, cyclopropyl-O-, HOC-, or HOC-CH2-O-, provided that X^7a and X^7b are not each O. In some embodiments of the above moieties 1 to 12, R⁸ is chloro, trifluoromethyl, or difluoromethyl-O-.

[0296] In some embodiments of the above moieties 1 to 12, X^a is O, CH2, or CHF; X^7a is O, CH2, or CH(CHs); X^7b is O or CH2; R⁷ is CH3; and R⁸ is chloro, trifluoromethyl, or difluoromethyl-O-, provided that X^7a and X^7b are not each O. In some embodiments of moieties 1 to 4, X^a is CH2; X^7a is CH2; X^7b is O; and R⁸ is chloro, trifluoromethyl, or difluoromethyl-O-. In some embodiments of moieties 1 to 4, X^a is O; X^7a is O; X^7b is CH2; and R⁸ is chloro, trifluoromethyl, or difluoromethyl-O-.

[0297] In some embodiments of Formula (la) or any one of related subformulae (II), (Ila),

(IIa-1), and (IIa-2), the moiety any one of the formulae according to Amine intermediates Al, A2, A4 to A6, and A9 to Al 11 in the Examples, wherein the nitrogen at the ring A is attached to the remainder of the molecule.

[0298] In some embodiments of Formula (II), (Ila), (IIa-1), or (IIa-2), or a subembodiment thereof, X² is O, NH, or CH2.

[0299] In some embodiments of Formula (II), (Ila), (IIa-1), or (IIa-2), or a subembodiment thereof, R^4a is H or C1-4 alkyl. In some embodiments, R^4a is H; or R^4a is methyl.

[0300] In some embodiments of Formula (II), (Ila), (IIa-1), or (IIa-2), or a subembodiment thereof, X2 is O, NH, or CH2; and R^4a is H or C1-4 alkyl. In some embodiments, X2 is O; and R^4a is H. In some embodiments, X2 is O; and R^4a is methyl. In some embodiments, X2 is NH; and R^4a is H. In some embodiments, X2 is NH; and R^4a is methyl. In some embodiments, X2 is CH2; and R^4a is H. In some embodiments, X2 is CH2; and R^4a is methyl.

[0301] In some embodiments of Formula (I), (la), (II), (Ila), (IIa-1), or (IIa-2), or a subembodiment thereof, wherein:

[0302] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, having Formula (lb) wherein,

X^a is O, CH₂, or CHR⁷; ring B is heteroaryl comprising 9 to 10 ring members with 1 to 4 heteroatom ring vertices, wherein each heteroatom is independently N, O, or S; p is 0, 1 or 2; and q is 0, 1, 2, or 3.

[0303] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein p is 1.

[0304] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein p is 2. [0305] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein q is 0.

[0306] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein q is 1.

[0307] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein q is 2.

[0308] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, having Formula (Ibl)

[0309] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein each R⁸ is independently Ci-6 alkyl, Ci-6 haloalkyl, halo, Ci-6 alkoxy, Ci-6 haloalkoxy, or heterocycloalkyl having 4 to 6 ring members with 1 to 3 heteroatom ring vertices, wherein each heteroatom is independently N, O, or S, and wherein the heterocycloalkyl is substituted with 0, 1 , or 2 R^8a.

[0310] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein each R⁸ is independently Ci-4 alkyl, Ci-4 haloalkyl, halo, or heterocycloalkyl having 4 to 6 ring members with 1 to 3 heteroatom ring vertices, wherein each heteroatom is independently N, O, or S, and wherein the heterocycloalkyl is substituted with 0, 1, or 2 R^8a.

[0311] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein each R⁸ is independently heterocycloalkyl having 4 to 6 ring members with 1 to 3 heteroatom ring vertices, wherein each heteroatom is independently N, O, or S, and wherein the heterocycloalkyl is substituted with 0, 1 , or 2 R^8a. [0312] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein each R⁸ is independently pyrrolidinyl, tetrahydrofuranyl, piperidinyl, piperazinyl, or morpholinyl substituted with 0, 1, or 2 R^8a.

[0313] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein each R⁸ is piperidinyl substituted with 0, 1, or 2 R^8a.

[0314] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein each R^8a is Cu alkyl.

[0315] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein each R^8a is independently methyl, ethyl, fluoro, chloro, bromo, fluoromethyl, difluoromethyl, or trifluoromethyl.

[0316] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein each R^8a is methyl.

[0317] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein the moiety [0318] In some embodiments of Formula (lb) or (Ibl), or any one of the embodiments thereof, the moiety

X² and R^4a are each defined and described herein. In some embodiments, X₂ is O, NH, or

CH₂; and R^4a is H or Ci-4 alkyl. In some embodiments, X₂ is O; and R^4a is H. In some embodiments, X₂ is O; and R^4a is methyl. In some embodiments, X₂ is NH; and R^4a is H. In some embodiments, X₂ is NH; and R^4a is methyl. In some embodiments, X₂ is CH₂; and R^4a is H. In some embodiments, X₂ is CH₂; and R^4a is methyl.

[0319] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein R⁹ is H, methyl, ethyl, fluoro, chloro, bromo, fluoromethyl, difluoromethyl, or trifluoromethyl.

[0320] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein R⁹ is H, methyl, fluoro, chloro, or trifluoromethyl.

[0321] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein R⁹ is H.

[0322] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein R⁹ is methyl.

[0323] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein R⁹ is fluoro.

[0324] In some embodiments, the compound or the pharmaceutically acceptable salt thereof, is the compound of Formula (I) or a subembodiment thereof, wherein the compound is selected from Table 1.

[0325] In some embodiments, the present disclosure provides a compound of Examples 1 to 3 and 5 to 112 in Table 1 or a pharmaceutically acceptable salt thereof. In some embodiments, a compound is selected from a compound of Examples 1 to 112, or a pharmaceutically acceptable salt thereof.

[0326] The present disclosure also includes prodrugs of the compound of Formula (I) or subembodiment thereof. As used herein, the term “prodrug” refers to compounds that readily undergo chemical changes under physiological conditions to provide a pharmacologically active parent compound. The term “prodrug moiety” refers to the chemical moiety of a prodrug that is released under physiological conditions to form the active parent compound. An example, without limitation, of a prodrug would be a compound which is administered as an ester (the “prodrug”), but then is metabolically hydrolyzed to the carboxylic acid, the active entity. Additionally, prodrugs can be converted to the compounds of the present disclosure by chemical or biochemical methods in an ex vivo environment. For example, prodrugs can be slowly converted to the compounds of the present disclosure when placed in a transdermal patch reservoir with a suitable enzyme or chemical reagent.

[0327] A number of compounds in Table 1, below, include one or more stereocenters. When the absolute stereochemistry of a stereocenter is known, the stereocenter in the displayed chemical structure is represented by a wedged solid (^) and/or dashed (••'' ) chemical bond(s) at the stereocenter without any markings or with the label of “(R)” or “(S)”. When the absolute stereochemistry of one or more stereocenters in an isolated compound is not known, the following labels are indicated at the stereocenter of the displayed structure: “&” (e.g., “&1”); or “or” (e.g., “orl,” “or2,” or “or3”). Each of these labels is further described below.

[0328] The label “&” in the structures in the present disclosure refers to both chiral centers being present in the mixture. When multiple stereocenters are labelled with “&1” the relative stereochemistry between them is determined. The term “rac” in the chemical names denotes a racemic mixture.

[0329] For example, Al is a racemic mixture of two isomers, wherein the relative stereochemistry between two centers labeled with “&1” is known, as shown below:

[0330] The label “or” in the structures refers to the specific chiral center being a single undefined isomer but absolute stereochemistry was not determined. When multiple stereocenters are labelled with different labels, the relative stereochemistry between them is not determined. For example, in a compound with stereocenters labelled as “orl” and “or2”, the relative stereochemistry between the differently labelled stereocenters is not determined. When multiple stereocenters are labelled with the same label, the relative stereochemistry between the same labelled stereocenters is determined but not the absolute stereochemistry. For example, for all stereocenters labelled “orl”, the relative stereochemistry between those stereocenters labelled “orl” is determined but not the absolute stereochemistry.

[0331] For example, A2 isomer 1 is a single isomer, wherein the relative stereochemistry between two chiral centers labeled with “orl” is known, but the absolute stereochemistry is not yet determined. A2 isomer can be either the S,S-isomer or R,R-isomer.

M., isomer 1

[0332] For example, A41 isomer 1 is a single isomer, wherein relative stereochemistry between two chiral centers labeled with the same “orl” is known; relative stereochemistry between chiral centers labeled with “orl” and “or2” is not known; and absolute stereochemistry of all three chiral centers is not yet determined. A41 isomer 1 can be any one of four isomers, as shown below:

Isomer 1

[0333] Unless otherwise indicated, Isomer 1 refers to the first eluting isomer and Isomer 2 refers to the second eluting isomer during chiral chromatographic separation. Similarly, Isomer 3 refers to a third eluting isomer, and Isomer 4 refers to a fourth eluting isomer during chiral chromatographic separation. Table 1: Exemplary Compounds

[0334] Additional compounds of Formula (I) can be prepared according to the general procedures as described in Examples 1-112 via a coupling reaction of any one of amines intermediates Al to Al 11 and any one of carboxylic acid intermediates CAI to CAI 1, wherein a combination of the amine and carboxylic acid intermediates is not used in Examples 1 to 112.

PHARMACEUTICAL COMPOSITIONS

[0335] The compounds of Formula (I) or pharmaceutically acceptable salts thereof, or subembodiments thereof may be in the form of compositions suitable for administration to a subject. In general, such compositions are pharmaceutical compositions comprising a compound of Formula (I) or a pharmaceutically acceptable salt thereof, or a subembodiment thereof, and one or more pharmaceutically acceptable excipients. The pharmaceutical compositions may be used in the methods disclosed herein; thus, for example, the pharmaceutical compositions can be administered ex vivo or in vivo to a subject in order to practice the therapeutic methods and uses described herein.

[0336] The pharmaceutical compositions can be formulated to be compatible with the intended method or route of administration; exemplary routes of administration are set forth herein. Furthermore, the pharmaceutical compositions may be used in combination with other therapeutic agents or compounds as described herein in order to treat the diseases, disorders and conditions contemplated by the present disclosure.

[0337] The pharmaceutical compositions containing the active ingredient (e.g., a compound of Formula (I), a pharmaceutically acceptable salt thereof)may be in a form suitable for oral use (for example as tablets, troches, lozenges, hard or soft capsules, aqueous or oily suspensions, emulsions, dispersible powders or granules, or syrups, solutions, microbeads or elixirs), for topical use (for example as creams, ointments, gels, or aqueous or oily solutions or suspensions), for administration by inhalation (for example as a finely divided powder or a liquid aerosol), for administration by insufflation (for example as a finely divided powder) or for parenteral administration (for example as a sterile aqueous or oily solution for intravenous, subcutaneous, intramuscular, intraperitoneal or intramuscular dosing or as a suppository for rectal dosing).

[0338] Pharmaceutical compositions intended for oral use may be prepared according to any method known to the art for the manufacture of pharmaceutical compositions, and such compositions may contain one or more agents such as, for example, sweetening agents, flavoring agents, coloring agents and preserving agents in order to provide pharmaceutically elegant and palatable preparations. Thus, compositions intended for oral use may contain, for example, one or more coloring, sweetening, flavoring and/or preservative agents. Tablets and/or capsules contain the active ingredient in admixture with non-toxic pharmaceutically acceptable excipients which are suitable for the manufacture of tablets and/or capsules. These excipients may be, for example, diluents, such as calcium carbonate, sodium carbonate, lactose, calcium phosphate or sodium phosphate; granulating and disintegrating agents, for example, com starch, or alginic acid; binding agents, for example starch, gelatin or acacia, and lubricating agents, for example magnesium stearate, stearic acid or talc.

[0339] The pharmaceutical compositions typically comprise a therapeutically effective amount of a compound of Formula (I) or a pharmaceutically acceptable salt thereof, and one or more pharmaceutically acceptable excipient. Suitable pharmaceutically acceptable excipients include, but are not limited to, antioxidants (e.g., ascorbic acid and sodium bisulfate), preservatives (e.g., benzyl alcohol, methyl parabens, ethyl or n-propyl, p- hydroxybenzoate), emulsifying agents, suspending agents, dispersing agents, solvents, fillers, bulking agents, detergents, buffers, vehicles, diluents, and/or adjuvants. For example, a suitable vehicle may be physiological saline solution or citrate buffered saline, possibly supplemented with other materials common in pharmaceutical compositions for parenteral administration. Neutral buffered saline or saline mixed with serum albumin are further exemplary vehicles. Those skilled in the art will readily recognize a variety of buffers that can be used in the pharmaceutical compositions and dosage forms contemplated herein. Typical buffers include, but are not limited to, pharmaceutically acceptable weak acids, weak bases, or mixtures thereof. As an example, the buffer components can be water soluble materials such as phosphoric acid, tartaric acids, lactic acid, succinic acid, citric acid, acetic acid, ascorbic acid, aspartic acid, glutamic acid, and salts thereof. Acceptable buffering agents include, for example, a Tris buffer, N-(2-Hydroxyethyl)piperazine-N'-(2- ethanesulfonic acid) (HEPES), 2-(N-Morpholino)ethanesulfonic acid (MES), 2-(N- Morpholino)ethanesulfonic acid sodium salt (MES), 3-(N-Morpholino)propanesulfonic acid (MOPS), and N-tris[Hydroxymethyl]methyl-3-aminopropanesulfonic acid (TAPS).

[0340] After a pharmaceutical composition has been formulated, it may be stored in sterile vials as a solution, suspension, gel, emulsion, solid, or dehydrated or lyophilized powder. Such formulations may be stored either in a ready-to-use form, a lyophilized form requiring reconstitution prior to use, a Equid form requiring dilution prior to use, or other acceptable form. In some embodiments, the pharmaceutical composition is provided in a single-use container (e.g., a single-use vial, ampoule, syringe, or autoinjector (similar to, e.g., an EpiPen®)), whereas a multi-use container (e.g., a multi-use vial) is provided in other embodiments.

[0341] Any drug delivery apparatus may be used to deliver the compounds, pharmaceutically acceptable salts thereof, or pharmaceutical compositions described herein including implants (e.g., implantable pumps) and catheter systems, slow injection pumps and devices, all of which are known in the art.

[0342] An effective amount of a compound of Formula (I) or a pharmaceutically acceptable salt thereof for use in therapy is an amount sufficient to treat or prevent a proliferative condition referred to herein, slow its progression and/or reduce the symptoms associated with the condition.

[0343] The size of the dose for therapeutic or prophylactic purposes of a compound of Formula (I) will naturally vary according to the nature and severity of the conditions, the age and sex of the animal or patient and the route of administration, according to well-known principles of medicine.

[0344] All the compounds and pharmaceutical compositions provided herein can be used in all the methods provided herein. For example, the compounds and pharmaceutical compositions provided herein can be used in all the methods for treatment and/or prevention of all diseases or disorders provided herein. Thus, the compounds and pharmaceutical compositions provided herein are for use as a medicament.

THERAPEUTIC USES AND APPLICATIONS

[0345] Provided herein are compounds that function as inhibitors of protein arginine N- methyltransferase 5 (PRMT5).

[0346] The present disclosure therefore provides a method of inhibiting PRMT5 enzyme activity in vitro or in vivo, said method comprising contacting a cell with an effective amount of a compound of Formula (I) or a pharmaceutically acceptable salt thereof, a subembodiment thereof, or a pharmaceutical composition as defined herein.

[0347] The present disclosure also provides a method of treating a disease or disorder in which PRMT5 activity is implicated in a patient, said method comprising administering to said patient a therapeutically effective amount of a compound of Formula (I) or a pharmaceutically acceptable salt thereof, a subembodiment thereof, or a pharmaceutical composition as defined herein. In some embodiments, the patient is in recognized need of such treatment. In an embodiment, the disease or disorder is cancer.

[0348] The present disclosure also provides a method of treating a disease or disorder treatable by inhibition of PRMT5 in a patient comprising administering to the patient a therapeutically effective amount of a compound of Formula (I) or a pharmaceutically acceptable salt thereof, a subembodiment thereof, or a pharmaceutical composition as defined herein. In some embodiments, the patient is in recognized need of such treatment. In an embodiment, the disease or disorder is cancer.

[0349] The present disclosure also provides a method of treating an MTAP null cancer in a patient comprising administering to the patient a therapeutically effective amount of a compound of Formula (I) or a pharmaceutically acceptable salt thereof, a subembodiment thereof, or a pharmaceutical composition as defined herein. In some embodiments, the patient is in recognized need of such treatment.

[0350] The present disclosure also provides a method of treating a cancer deficient in CDKN2A in a patient comprising administering to the patient a therapeutically effective amount of a compound of Formula (I) or a pharmaceutically acceptable salt thereof, a subembodiment thereof, or a pharmaceutical composition as defined herein. In some embodiments, the patient is in recognized need of such treatment.

[0351] The present disclosure also provides a method of treating cancer in a patient, wherein the cancer is characterized by a reduction or absence of MTAP gene expression, an absence of the MTAP gene, an absence of MTAP protein, a reduced level of MTAP protein, a reduced function of MTAP protein, or a combination thereof, comprising administering to the patient a therapeutically effective amount of a compound of Formula (I) or a pharmaceutically acceptable salt thereof, a subembodiment thereof, or a pharmaceutical composition as defined herein. In some embodiments, the patient is in recognized need of such treatment.

[0352] The present disclosure also provides a method of treating cancer in a patient comprising administering to the patient a therapeutically effective amount of a compound of Formula (I) or a pharmaceutically acceptable salt thereof, a subembodiment thereof, or a pharmaceutical composition as defined herein. In some embodiments, the patient is in recognized need of such treatment.

[0353] The present disclosure also provides a method of inhibiting cell profiferation, in vitro or in vivo, said method comprising contacting a cell with an effective amount of a compound of Formula (I) or a pharmaceutically acceptable salt thereof, a subembodiment thereof, or a pharmaceutical composition as defined herein.

[0354] The present disclosure also provides a method of treating a proliferative disorder in a patient in need of such treatment, said method comprising administering to said patient a therapeutically effective amount of a compound of Formula (I) or a pharmaceutically acceptable salt thereof, a subembodiment thereof, or a pharmaceutical composition as defined herein. In an embodiment, the proliferative disorder is cancer.

[0355] Provided herein is a compound of Formula (I) or a pharmaceutically acceptable salt thereof, a subembodiment thereof, or a pharmaceutical composition as defined herein for use in therapy.

[0356] Provided herein is a compound of Formula (I) or a pharmaceutically acceptable salt thereof, a subembodiment thereof, or a pharmaceutical composition as defined herein for use in the treatment of cancer. In some embodiments, the patient is in recognized need of such treatment. [0357] Provided herein is a compound of Formula (I) or a pharmaceutically acceptable salt thereof, a subembodiment thereof, or a pharmaceutical composition as defined herein for use in the inhibition of PRMT5 enzyme activity.

[0358] Provided herein is a compound of Formula (I) or a pharmaceutically acceptable salt thereof, a subembodiment thereof, or a pharmaceutical composition as defined herein for use in the treatment of a disease or disorder in which PRMT5 activity is implicated.

[0359] Provided herein is a compound of Formula (I) or a pharmaceutically acceptable salt thereof, a subembodiment thereof, or a pharmaceutical composition as defined herein for use in the treatment of a disease or disorder treatable by inhibition of PRMT5.

[0360] Provided herein is a use of a compound of Formula (I) or a pharmaceutically acceptable salt thereof, a subembodiment thereof, or a pharmaceutical composition as defined herein in the manufacture of a medicament for the treatment of a proliferative condition. In some embodiments, the patient is in recognized need of such treatment.

[0361] Provided herein is a use of a compound of Formula (I) or a pharmaceutically acceptable salt thereof, a subembodiment thereof, or a pharmaceutical composition as defined herein in the manufacture of a medicament for the treatment of cancer. In some embodiments, the patient is in recognized need of such treatment.

[0362] Provided herein is a use of a compound of Formula (I) or a pharmaceutically acceptable salt thereof, a subembodiment thereof, or a pharmaceutical composition as defined herein in the manufacture of a medicament for the inhibition of PRMT5 enzyme activity.

[0363] Provided herein is a use of a compound of Formula (I) or a pharmaceutically acceptable salt thereof, a subembodiment thereof, or a pharmaceutical composition as defined herein in the manufacture of a medicament for the treatment of a disease or disorder in which PRMT5 activity is implicated.

[0364] Provided herein is a use of a compound of Formula (I) or a pharmaceutically acceptable salt thereof, a subembodiment thereof, or a pharmaceutical composition as defined herein in the manufacture of a medicament for the treatment of a disease or disorder treatable by inhibition of PRMT5.

[0365] In another aspect, the present disclosure provides a method of treating a cancer in a patient, comprising: (i) determining if the cancer is MTAP null; and

(ii) if the cancer is MTAP null, administering to the patient a therapeutically effective amount of a compound as disclosed herein or a pharmaceutically acceptable salt thereof, or a pharmaceutical composition as defined herein.

[0366] In some embodiments, the cancers described herein are a solid tumor. In some embodiments, the solid tumor is malignant. In some embodiments, the cancers described herein are a metastatic solid tumor.

[0367] In some embodiments, the cancer treated by the methods, uses, or medicaments described herein is neuroblastoma, intestine carcinoma (such as rectum carcinoma, colon carcinoma, familial adenomatous polyposis carcinoma and hereditary nou-polyposis colorectal cancer), esophageal carcinoma, labial carcinoma, larynx carcinoma, hypopharynx carcinoma, tongue carcinoma, salivary⁷ gland carcinoma, gastric carcinoma, adenocarcinoma, medullary thyroid carcinoma, papillary thyroid carcinoma, renal carcinoma, kidney parenchym carcinoma, ovarian carcinoma, cervix carcinoma, uterine corpus carcinoma, endometrium carcinoma, chorion carcinoma, pancreatic carcinoma, prostate carcinoma, testis carcinoma, breast carcinoma, urinary carcinoma, melanoma, brain tumors (such as glioblastoma, astrocytoma, meningioma, medulloblastoma and peripheral neuroectodermal tumors), Hodgkin lymphoma, non-Hodgkin lymphoma, Burkitt lymphoma, acute lymphoblastic leukemia (ALL), chronic lymphoblastic leukemia (CLL), acute myeloid leukemia (AMI.), chronic myeloid leukemia (CML), adult T-cell leukemia, hepatocellular carcinoma, gall bladder carcinoma, bronchial carcinoma, small cell lung carcinoma, nonsmall cell lung carcinoma, multiple myeloma, basalioma, teratoma, retinoblastoma, choroidea melanoma, seminoma, rhabdomyo sarcoma, craniopharyngeoma, osteosarcoma, chondrosarcoma, myosarcoma, liposarcoma, fibrosarcoma, Ewing sarcoma or plasmocytoma.

[0368] In some embodiments, the cancer treated by the methods, uses, or medicaments described herein is lung cancer, non-small cell lung (NSLC) cancer, bronchioloalveolar cell lung cancer, bone cancer, pancreatic cancer, skin cancer, cancer of the head or neck, cutaneous or intraocular melanoma, uterine cancer, ovarian cancer, rectal cancer, cancer of the anal region, stomach cancer, gastric cancer, colon cancer, breast cancer, uterine cancer, carcinoma of the fallopian tubes, carcinoma of the endometrium, carcinoma of the vagina, carcinoma of tire vulva, cancer of the small intestine, cancer of the endocrine system, cancer of the thyroid gland, cancer of the parathyroid gland, cancer of tire adrenal gland, sarcoma of soft tissue, cancer of the urethra, cancer of the penis, prostate cancer, cancer of the bladder, cancer of the kidney or ureter, renal cell carcinoma, carcinoma of the renal pelvis, mesothelioma, hepatocellular cancer, biliary cancer, chronic or acute leukemia, lymphocytic lymphomas, neoplasms of the central nervous system (CNS), spinal axis tumors, brain stem glioma, glioblastoma multiforme, astrocytomas, schwannomas, ependymomas, medulloblastomas, meningiomas, squamous cell carcinomas, pituitary adenomas, including refractory versions of any of the above cancers, or a combination of one or more of the above cancers.

[0369] In some embodiments, the cancer treated by the methods, uses, or medicaments described herein is leukemia, glioma, melanoma, pancreatic, non-small cell lung cancer (NSLC), bladder cancer, astrocytoma, osteosarcoma, head and neck cancer, myxoid chondrosarcoma, ovarian cancer, endometrial cancer, breast cancer, soft tissue sarcoma, nonHodgkin lymphoma or mesothelioma.

[0370] In some embodiments, the cancer treated by the methods, uses, or medicaments described herein is bladder cancer, melanoma, brain cancer, lung cancer, pancreatic cancer, breast cancer, esophageal cancer, head and neck cancer, kidney cancer, colon cancer, diffuse large B cell lymphoma (DLBCL), acute lymphoblastic leukemia (ALL) or mantle cell lymphoma (MCL).

[0371] In some embodiments, the cancer treated by the methods, uses, or medicaments described herein is gastric cancer. In some embodiments, the cancer treated by the methods, uses, or medicaments described herein is colon cancer. In some embodiments, the cancer treated by the methods, uses, or medicaments described herein is liver cancer. In some embodiments, the cancer treated by the methods, uses, or medicaments described herein is glioblastoma multiforme (GBM). In some embodiments, the cancer treated by the methods, uses, or medicaments described herein is bladder cancer. In some embodiments, the cancer treated by the methods, uses, or medicaments described herein is esophageal cancer. In some embodiments, the cancer treated by the methods, uses, or medicaments described herein is breast cancer. In some embodiments, the cancer treated by the methods, uses, or medicaments described herein is NSLCC. In some embodiments, the cancer treated by the methods, uses, or medicaments described herein is MCL. In some embodiments, the cancer treated by the methods, uses, or medicaments described herein is DLBCL. In some embodiments, the cancer treated by the methods, uses, or medicaments described herein is ALL.

[0372] In some embodiments, the cancer treated by the methods, uses, or medicaments described herein is leukemia, esophageal cancer, glioma, melanoma, pancreatic, non-small cell lung cancer, bladder cancer, astrocytoma, osteosarcoma, head and neck cancer, myxoid chondrosarcoma, ovarian cancer, endometrial cancer, breast cancer, soft tissue sarcoma, nonHodgkin lymphoma or mesothelioma. In some embodiments, the cancer is non-small cell lung cancer (squamous and adenocarcinoma), urothelial cancer (bladder and upper urinary tract), esophageal cancer, or gastric cancer.

[0373] In some embodiments, the cancer treated by the methods, uses, or medicaments described herein is biliary tract cancer, glioblastoma, ovarian cancer, malignant peripheral nerve sheath tumors (MPNST), colon cancer, esophageal cancer (e.g., esophageal squamous cell carcinoma or esophageal adenocarcinoma), gastric cancer, bladder cancer (e.g., bladder urothelial carcinoma, gallbladder cancer), pancreatic cancer ( e.g., pancreatic adenocarcinoma), mesothelioma, melanoma, lung cancer (e.g., non-small cell lung cancer (NSCLC; e.g., lung squamous or lung adenocarcinoma)), astrocytoma, undifferentiated pleiomorphic sarcoma, lymphoma (e.g., diffuse large B-cell lymphoma (DLBCL)), leukemia, head and neck cancer (e.g., head and neck squamous cell carcinoma), stomach adenocarcinoma, myxofibrosarcoma, cholangiosarcoma, cancer of the brain, stomach, kidney, breast, endometrium, urinary tract, Ever, soft tissue, pleura and large intestine or sarcoma.

[0374] In some embodiments, the cancer treated by the methods, uses, or medicaments described herein is an MTA-accumulating cancer. In some embodiments, the cancer treated by the methods, uses, or medicaments described herein is an MTAP-deficient cancer. In some embodiments, the cancer is treatable by inhibition of PRMT5.

[0375] The disclosure further relates to the use of compounds disclosed herein for the treatment and/or prophylaxis of diseases and/or conditions through inhibiting PRMT5 by said compounds. The disclosure further relates to the use of compounds disclosed herein for the treatment and/or prophylaxis of diseases and/or conditions through inhibiting PRMT5 by said compounds. The disclosure further relates to the use of compounds disclosed herein for the treatment and/or prophylaxis of diseases and/or conditions through inhibiting PRMT5 in MTAP- null cells by said compounds. Further, the present disclosure relates to the use of said compounds for the preparation of a medicament for the treatment and/or prophylaxis of a chromosome 9p21 deletion or MTAP-null associated disease and/or condition through inhibiting PRMT5 in MTAP-null cells by said compounds. In some embodiments the chromosome 9p21 deletion or MTAP-null associated disease or condition is alleviated by inhibition of PRMT5 in MTAP-null cells.

[0376] In some embodiments, provided herein is a method of treating and/or preventing a MTAP-null or chromosome 9p21 deletion associated disease or condition in a patient in need thereof, comprising administering to the patient a therapeutically effective amount of a compound of Formula (I) or a pharmaceutically acceptable salt thereof, a subembodiment thereof, or a pharmaceutical composition as defined herein.

[0377] In some embodiments, the chromosome 9p21 deletion or MTAP-null associated disease or condition includes a solid tumor in or arising from a tissue or organ, such as: • bone (e.g., adamantinoma, aneurysmal bone cysts, angiosarcoma, chondroblastoma, chondroma, chondromyxoid fibroma, chondrosarcoma, chordoma, dedifferentiated chondrosarcoma, enchondroma, epithelioid hemangioendothelioma, fibrous dysplasia of the bone, giant cell tumour of bone, haemangiomas and related lesions, osteoblastoma, osteochondroma, osteosarcoma, osteoid osteoma, osteoma, periosteal chondroma, Desmoid tumor, Ewing sarcoma); • lips and oral cavity (e.g., odontogenic ameloblastoma, oral leukoplakia, oral squamous cell carcinoma, primary oral mucosal melanoma); salivary glands (e.g., pleomorphic salivary gland adenoma, salivary gland adenoid cystic carcinoma, salivary gland mucoepidermoid carcinoma, salivary gland Warthin's tumors); • esophagus (e.g., Barrett's esophagus, dysplasia and adenocarcinoma); • gastrointestinal tract, including stomach (e.g., gastric adenocarcinoma, primary gastric lymphoma, gastrointestinal stromal tumors (GISTs), metastatic deposits, gastric carcinoids, gastric sarcomas, neuroendocrine carcinoma, gastric primary squamous cell carcinoma, gastric adenoacanthomas), intestines and smooth muscle (e.g., intravenous leiomyomatosis), colon (e.g., colorectal adenocarcinoma), rectum, anus; • pancreas (e.g., serous neoplasms, including microcystic or macrocystic serous cystadenoma, solid serous cystadenoma, Von Hippel-Landau (VHL)- associated serous cystic neoplasm, serous cystadenocarcinoma; mucinous cystic neoplasms (MCN), intraductal papillary mucinous neoplasms (IPMN), intraductal oncocytic papillary neoplasms (IOPN), intraductal tubular neoplasms, cystic acinar neoplasms, including acinar cell cystadenoma, acinar cell cystadenocarcinoma, pancreatic adenocarcinoma, invasive pancreatic ductal adenocarcinomas, including tubular adenocarcinoma, adenosquamous carcinoma, colloid carcinoma, medullary carcinoma, hepatoid carcinoma, signet ring cell carcinoma, undifferentiated carcinoma, undifferentiated carcinoma with osteoclast-like giant cells, acinar cell carcinoma, neuroendocrine neoplasms, neuroendocrine microadenoma, neuroendocrine tumors (NET), neuroendocrine carcinoma (NEC), including small cell or large cell NEC, insulinoma, gastrinoma, glucagonoma, serotonin-producing NET, somatostatinoma, VIPoma, solid- pseudopapillary neoplasms (SPN), pancreatoblastoma); • gall bladder (e.g., carcinoma of the gallbladder and extrahepatic bile ducts, intrahepatic cholangiocarcinoma); • neuro-endocrine (e.g., adrenal cortical carcinoma, carcinoid tumors, phaeochromocytoma, pituitary adenomas); • thyroid (e.g., anaplastic (undifferentiated) carcinoma, medullary carcinoma, oncocytic tumors, papillary carcinoma, adenocarcinoma); • liver (e.g., adenoma, combined hepatocellular and cholangiocarcinoma, fibrolamellar carcinoma, hepatoblastoma, hepatocellular carcinoma, mesenchymal, nested stromal epithelial tumor, undifferentiated carcinoma; hepatocellular carcinoma, intrahepatic cholangiocarcinoma, bile duct cystadenocarcinoma, epithelioid hemangioendothelioma, angiosarcoma, embryonal sarcoma, rhabdomyosarcoma, solitary fibrous tumor, teratoma, York sac tumor, carcinosarcoma, rhabdoid tumor); • kidney (e.g., ALK-rearranged renal cell carcinoma, chromophobe renal cell carcinoma, clear cell renal cell carcinoma, clear cell sarcoma, metanephric adenoma, metanephric adenofibroma, mucinous tubular and spindle cell carcinoma, nephroma, nephroblastoma (Wilms tumor), papillary adenoma, papillary renal cell carcinoma, renal oncocytoma, renal cell carcinoma, succinate dehydrogenasedeficient renal cell carcinoma, collecting duct carcinoma); • breast (e.g., invasive ductal carcinoma, including without limitation, acinic cell carcinoma, adenoid cystic carcinoma, apocrine carcinoma, cribriform carcinoma, glycogen-rich/clear cell, inflammatory carcinoma, lipid-rich carcinoma, medullary carcinoma, metaplastic carcinoma, micropapillary carcinoma, mucinous carcinoma, neuroendocrine carcinoma, oncocytic carcinoma, papillary carcinoma, sebaceous carcinoma, secretory breast carcinoma, tubular carcinoma; lobular carcinoma, including without limitation, pleomorphic carcinoma, signet ring cell carcinoma; • peritoneum (e.g., mesothelioma; primary peritoneal cancer); • female sex organ tissues, including ovary (e.g., choriocarcinoma, epithelial tumors, germ cell tumors, sex cord-stromal tumors), Fallopian tubes (e.g., serous adenocarcinoma, mucinous adenocarcinoma, endometrioid adenocarcinoma, clear cell adenocarcinoma, transitional cell carcinoma, squamous cell carcinoma, undifferentiated carcinoma, Mullerian tumors, adenosarcoma, leiomyosarcoma, teratoma, germ cell tumors, choriocarcinoma, trophoblastic tumors), uterus (e.g., carcinoma of the cervix, endometrial polyps, endometrial hyperplasia, intraepithelial carcinoma (EIC), endometrial carcinoma (e.g., endometrioid carcinoma, serous carcinoma, clear cell carcinoma, mucinous carcinoma, squamous cell carcinoma, transitional carcinoma, small cell carcinoma, undifferentiated carcinoma, mesenchymal neoplasia), leiomyoma (e.g., endometrial stromal nodule, leiomyosarcoma, endometrial stromal sarcoma (ESS), mesenchymal tumors), mixed epithelial and mesenchymal tumors (e.g., adenofibroma, carcinofibroma, adenosarcoma, carcinosarcoma (malignant mixed mesodermal sarcoma - MMMT)), endometrial stromal tumors, endometrial malignant mullerian mixed tumours, gestational trophoblastic tumors (partial hydatiform mole, complete hydatiform mole, invasive hydatiform mole, placental site tumour)), vulva, vagina; • male sex organ tissues, including prostate, testis (e.g., germ cell tumors, spermatocytic seminoma), penis; • bladder (e.g., squamous cell carcinoma, urothelial carcinoma, bladder urothelial carcinoma); • brain, (e.g., gliomas (e.g., astrocytomas, including non-infiltrating, low-grade, anaplastic, glioblastomas; oligodendrogliomas, ependymomas), meningiomas, gangliogliomas, schwannomas (neurilemmomas), craniopharyngiomas, chordomas, Non-Hodgkin lymphomas (NHLs), indolent non-Hodgkin’s lymphoma (iNHL), refractory iNHL, pituitary tumors; • eye (e.g., retinoma, retinoblastoma, ocular melanoma, posterior uveal melanoma, iris hamartoma); • head and neck (e.g., nasopharyngeal carcinoma, Endolymphatic Sac Tumor (ELST), epidermoid carcinoma, laryngeal cancers including squamous cell carcinoma (SCC) (e.g., glottic carcinoma, supraglottic carcinoma, subglottic carcinoma, transglottic carcinoma), carcinoma in situ, verrucous, spindle cell and basaloid SCC, undifferentiated carcinoma, laryngeal adenocarcinoma, adenoid cystic carcinoma, neuroendocrine carcinomas, laryngeal sarcoma), head and neck paragangliomas (e.g., carotid body, jugulotympanic, vagal); • thymus (e.g., thymoma); • heart (e.g., cardiac myxoma); • lung (e.g., small cell carcinoma (SCLC), non-small cell lung carcinoma (NSCLC), including squamous cell carcinoma (SCC), adenocarcinoma and large cell carcinoma, carcinoids (typical or atypical), carcinosarcomas, pulmonary blastomas, giant cell carcinomas, spindle cell carcinomas, pleuropulmonary blastoma); • lymph (e.g., lymphomas, including Hodgkin’s lymphoma, nonHodgkin’s lymphoma (NHL), indolent non-Hodgkin’s lymphoma (iNHL), refractory iNHL, Epstein-Barr virus (EBV)-associated lymphoproliferative diseases, including B cell lymphomas and T cell lymphomas (e.g., Burkitt lymphoma; large B cell lymphoma, diffuse large B-cell lymphoma (DLBCL), mantle cell lymphoma, indolent B-cell lymphoma, low grade B cell lymphoma, fibrin-associated diffuse large cell lymphoma; primary effusion lymphoma; plasmablastic lymphoma; extranodal NK/T cell lymphoma, nasal type; peripheral T cell lymphoma, cutaneous T cell lymphoma, angioimmunoblastic T cell lymphoma; follicular T cell lymphoma; systemic T cell lymphoma), lymphangioleiomyomatosis); • central nervous system (CNS) (e.g., gliomas including astrocytic tumors (e.g., pilocytic astrocytoma, pilomyxoid astrocytoma, subependymal giant cell astrocytoma, pleomorphic xanthoastrocytoma, diffuse astrocytoma, fibrillary astrocytoma, gemistocytic astrocytoma, protoplasmic astrocytoma, anaplastic astrocytoma, glioblastoma (e.g., giant cell glioblastoma, gliosarcoma, glioblastoma multiforme) and gliomatosis cerebri), oligodendroglial tumors (e.g., oligodendroglioma, anaplastic oligodendroglioma), oligoastrocytic tumors (e.g., oligoastrocytoma, anaplastic oligoastrocytoma), ependymal tumors (e.g., subependymom, myxopapillary ependymoma, ependymomas (e.g., cellular, papillary, clear cell, tanycytic), anaplastic ependymoma), optic nerve glioma, and non-gliomas (e.g., choroid plexus tumors, neuronal and mixed neuronal-glial tumors, pineal region tumors, embryonal tumors, medulloblastoma, meningeal tumors, primary CNS lymphomas, germ cell tumors, Pituitary adenomas, cranial and paraspinal nerve tumors, stellar region tumors); neurofibroma, meningioma, peripheral nerve sheath tumors, peripheral neuroblastic tumours (including without limitation neuroblastoma, ganglion euroblastoma, ganglioneuroma), trisomy 19 ependymoma); • neuroendocrine tissues (e.g., paraganglionic system including adrenal medulla (pheochromocytomas) and extra-adrenal paraganglia ((extra-adrenal) paragangliomas); • skin (e.g., clear cell hidradenoma, cutaneous benign fibrous histiocytomas, cylindroma, hidradenoma, melanoma (including cutaneous melanoma, mucosal melanoma), pilomatricoma, Spitz tumors); and • soft tissues (e.g., aggressive angiomyxoma, alveolar rhabdomyosarcoma, alveolar soft part sarcoma, angiofibroma, angiomatoid fibrous histiocytoma, synovial sarcoma, biphasic synovial sarcoma, clear cell sarcoma, dermatofibrosarcoma protuberans, desmoid-type fibromatosis, small round cell tumor, desmoplastic small round cell tumor, elastofibroma, embryonal rhabdomyosarcoma, Ewing's tumors/primitive neurectodermal tumors (PNET), extraskeletal myxoid chondrosarcoma, extraskeletal osteosarcoma, paraspinal sarcoma, inflammatory myofibroblastic tumor, lipoblastoma, lipoma, chondroid lipoma, liposarcoma / malignant lipomatous tumors, liposarcoma, myxoid liposarcoma, fibromyxoid sarcoma, lymphangioleiomyoma, malignant myoepithelioma, malignant melanoma of soft parts, myoepithelial carcinoma, myoepithelioma, myxoinflammatory fibroblastic sarcoma, undifferentiated sarcoma, pericytoma, rhabdomyosarcoma, non-rhabdomyosarcoma soft tissue sarcoma (NRSTS), soft tissue leiomyosarcoma, undifferentiated sarcoma, well- differentiated liposarcoma.

[0378] In some embodiments, the chromosome 9p21 deletion or MTAP-null associated disease or condition is a cancer selected from lung cancer, urothelial cancer, pancreatic cancer, esophageal cancer, bladder cancer, melanoma, mature B-cell neoplasms, head and neck cancer, bile duct cancer, esophagus cancer, glioblastoma, stomach cancer, adrenal cancer, breast cancer, ovarian cancer, thymic epithelial tumor, Ever cancer, renal cancer, colorectal cancer, prostate cancer, leukemia, and cervical cancer.

[0379] In some embodiments, the chromosome 9p21 deletion or MTAP-null associated disease or condition is a cancer is selected from ovarian, lung, lymphoid, glioblastoma, colon, melanoma, gastric, pancreatic, and bladder cancer.

[0380] In some embodiments, the cancer treated by the methods, uses, or medicaments described herein is pancreatic cancer. In some embodiments, the cancer treated by the methods, uses, or medicaments described herein is multiple myeloma (MM). In some embodiments, the cancer treated by the methods, uses, or medicaments described herein is breast cancer. The breast cancer can be estrogen receptor negative (ER-) or the breast cancer can be progesterone receptor negative (PR-). In further embodiments, the breast cancer can be HER2 negative. In some embodiments, the breast cancer is estrogen receptor negative, progesterone receptor negative and HER2 negative, also referred to herein as "triple negative breast cancer".

[0381] In further aspects, a breast cancer can be a lobular carcinoma in situ (LCIS), a ductal carcinoma in situ (DOS), an invasive ductal carcinoma (IDC), inflammatory breast cancer, Paget disease of the nipple, Phyllodes tumor, Angiosarcoma, adenoid cystic carcinoma, low-grade adenosquamous carcinoma, medullary carcinoma, mucinous carcinoma, papillary carcinoma, tubular carcinoma, metaplastic carcinoma, micropapary carcinoma, mixed carcinoma, or another breast cancer, including but not limited to triple negative, HER positive, estrogen receptor positive, progesterone receptor positive, HER and estrogen receptor positive, HER and progesterone receptor positive, estrogen and progesterone receptor positive, and HER and estrogen and progesterone receptor positive. [0382] In an embodiment, the cancer treated by the methods, uses, or medicaments described herein is pancreatic cancer.

[0383] In some embodiments, the cancer treated by the methods, uses, or medicaments described herein is NSCLC (non-small cell lung carcinoma. In one embodiment, the NSCLC can be squamous NSCLC. In another embodiment, it can be adenocarcinoma. [082] In a further aspect, cancer can be glioblastoma (GBM). In a further aspect, cancer can be mesothelioma. In one aspect, cancer can be bladder cancer. In another aspect, cancer can be esophageal cancer. In a further aspect, cancer can be melanoma. In one aspect, cancer can be DLBCL, HNSCC or cholangiocarcinoma.

[0384] In some aspects, one or more compounds described herein are useful for treating any PRMT5- mediated or PRMT5-responsive proliferative cell disorder, for example a cancer that is PRMT5 responsive.

[0385] In one aspect, a cancer that lacks p53 (e.g., a p53 null cancer) is less sensitive to PRMT5 inhibition than a cancer that is p5 positive. Accordingly, a cancer that is PRMT5 responsive can be a p53 positive cancer. The term "p53 positive" refers to a cancer that does not lack p53 expression and/or activity. In some embodiments, one or more compounds described herein are useful for treating a p53 positive cancer. In some aspects, a greater amount of one or more compounds described herein may be required to treat a p53 negative cancer (e.g. , a p53 null cancer) than a p53 positive cancer.

[0386] In some aspects, the disclosure provides a method for identifying subjects having a cancer that is sensitive to treatment with a PRMT5 inhibitor. In some embodiments, the method comprises obtaining a sample from the subject; detecting the presence or absence of p53; and, identifying the subject as having a cancer that is sensitive to treatment with a PRMT5 inhibitor if p53 is present in the sample. Accordingly, in some embodiments, a subject having a p53 positive cancer is identified as a subject for treatment with a PRMT5 inhibitor. In some embodiments, the method further comprises administering to the subject a composition comprising a PRMT5 inhibitor.

[0387] In some embodiments, the disclosure relates to a method for identifying subjects having a cancer that is insensitive (or that has low sensitivity) to treatment with a PRMT5 inhibitor. In some embodiments, the method comprises obtaining a sample from the subject; detecting the presence or absence of p53 ; and, identifying the subject as having a cancer that is not sensitive (for example, a cancer that is less sensitive than a p53 positive cancer) to treatment with a PRMT5 inhibitor if p53 is absent from the sample (e.g., if the cancer is a p53 null cancer). In some embodiments, a p53 negative cancer (e.g., a p53 null cancer) is treated with a PRMT5 inhibitor, but a greater amount of PRMT5 inhibitor may be required to treat the p53 negative cancer than a p53 positive cancer. However, in some embodiments, a subject having a p53 negative cancer (e.g. , a p53 null cancer) is treated with a therapeutic agent that is not a PRMT5 inhibitor.

[0388] By "sample" is meant any biological sample derived from the subject, includes but is not limited to, cells, tissues samples, body fluids (including, but not limited to, mucus, blood, plasma, serum, urine, saliva, and semen), cancer cells, and cancer tissues. Detection of the presence or absence of p53 in the sample may be achieved by any suitable method for detecting p53 nucleic acid or protein, for example, nucleic acid sequencing (e.g., DNA or RNA sequencing), quantitative PCR, Western blotting, etc., or any combination of thereof.

[0389] In some embodiments, the cancer treated by the methods, uses, or medicaments described herein is acoustic neuroma, adenocarcinoma, adrenal gland cancer, anal cancer, angiosarcoma (e.g., lymphangiosarcoma, lymphangioendotheliosarcoma, hemangio sarcoma), appendix cancer, benign monoclonal gammopathy, biliary cancer (e.g. , cholangiocarcinoma), bladder cancer, brain cancer (e.g., meningioma; glioma, e.g. , astrocytoma, oligodendroglioma; medulloblastoma), bronchus cancer, carcinoid tumor, cervical cancer (e.g. , cervical adenocarcinoma), choriocarcinoma, chordoma, craniopharyngioma, colorectal cancer (e.g., colon cancer, rectal cancer, colorectal adenocarcinoma), epithelial carcinoma, ependymoma, endothelio sarcoma (e.g., Kaposi's sarcoma, multiple idiopathic hemorrhagic sarcoma), endometrial cancer (e.g., uterine cancer, uterine sarcoma), esophageal cancer (e.g. , adenocarcinoma of the esophagus, Barrett' s adenocarinoma), Ewing sarcoma, eye cancer (e.g., intraocular melanoma, retinoblastoma), familiar hypereosinophilia, gall bladder cancer, gastric cancer (e.g. , stomach adenocarcinoma), gastrointestinal stromal tumor (GIST), head and neck cancer (e.g., head and neck squamous cell carcinoma, oral cancer (e.g., oral squamous cell carcinoma (OSCC), throat cancer (e.g., laryngeal cancer, pharyngeal cancer, nasopharyngeal cancer, oropharyngeal cancer)), hematopoietic cancers (e.g., leukemia such as acute lymphocytic leukemia (ALL) (e.g., B-cell ALL, T-cell ALL), acute myelocytic leukemia (AML) (e.g. , fl- cel! AML, T-cell AML), chronic myelocytic leukemia (CML) (e g. , B-cell CML, T-cell CML), and chronic lymphocytic leukemia (CLL) (e.g. , B-cell CLL, T- cell CLL), follicular lymphoma, chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL), marginal zone B-cell lymphomas (e.g. , mucosa-associated lymphoid tissue (MALT) lymphomas, nodal marginal zone B-cell lymphoma, splenic marginal zone B-cell lymphoma), primary mediastinal B-cell lymphoma, Burkitt lymphoma, lymphoplasmacytic lymphoma (e.g., "Waldenstrom's macro globulinemia"), hairy cell leukemia (HCL), immunoblastic large cell ly mphoma, precursor B -lymphoblastic lymphoma and primary central nervous system (CNS) lymphoma; and T-cell NHL such as precursor T- lymphoblastic lymphoma/leukemia, peripheral T-cell lymphoma (PTCL) (e.g., cutaneous T- cell lymphoma (CTCL) (e.g. , mycosis fungiodes, Sezary syndrome), angioimmunoblastic T- cell lymphoma, extranodal natural killer T-cell lymphoma, enteropathy type T-cell lymphoma, subcutaneous panniculitis- like T-cell lymphoma, anaplastic large cell lymphoma); a mixture of one or more leukemia/lymphoma as described above; and multiple myeloma (MM)), heavy chain disease (e.g., alpha chain disease, gamma chain disease, mu chain disease), hemangioblastoma, inflammatory myofibroblastic tumors, immunocytic amyloidosis, kidney cancer (e g., nephroblastoma a.k.a. Wilms' tumor, renal cell carcinoma), liver cancer (e.g. , hepatocellular cancer (HCC), malignant hepatoma), lung cancer (e.g., bronchogenic carcinoma, small cell lung cancer (SCLC), non-small cell lung cancer (NSCLC), adenocarcinoma of the lung), leiomyosarcoma (LMS), mastocytosis (e.g. , systemic mastocytosis), myelodysplasia syndrome (MDS), mesothelioma, myeloproliferative disorder (MPD) (e.g., polycythemia Vera (PV), essential thrombocytosis (ET), agnogenic myeloid metaplasia (AMM) a.k.a. myelofibrosis (MF), chronic idiopathic myelofibrosis, chronic myelocytic leukemia (CML), chronic neutrophilic leukemia (CNL), hypereosinophilic syndrome (HES)), neuroblastoma, neurofibroma (e.g. , neurofibromatosis (NF) type 1 or type 2, schwannomatosis), neuroendocrine cancer (e.g., gastroenteropancreatic neuroendoctrine tumor (GEP-NET), carcinoid tumor), osteosarcoma, ovarian cancer (e.g. , cystadenocarcinoma, ovarian embryonal carcinoma, ovarian adenocarcinoma), papillary adenocarcinoma, penile cancer (e.g., Paget' s disease of the penis and scrotum), pinealoma, primitive neuroectodermal tumor (PNT), prostate cancer (e.g., prostate adenocarcinoma), rectal cancer, rhabdomyosarcoma, salivary gland cancer, skin cancer (e.g. , squamous cell carcinoma (SCC), keratoacanthoma (KA), melanoma, basal cell carcinoma (BCC)), small bowel cancer (e.g. , appendix cancer), soft tissue sarcoma (e.g., malignant fibrous histiocytoma (MFH), liposarcoma, malignant peripheral nerve sheath tumor (MPNST), chondrosarcoma, fibrosarcoma, myxosarcoma), sebaceous gland carcinoma, sweat gland carcinoma, synovioma, testicular cancer (e.g., seminoma, testicular embryonal carcinoma), thyroid cancer (e.g., papillary carcinoma of the thyroid, papillary thyroid carcinoma (PTC), medullary thyroid cancer), urethral cancer, vaginal cancer and vulvar cancer (e.g., Paget's disease of the vulva).

[0390] In some embodiments, the cancer treated by the methods, uses, or medicaments described herein is spinal cord cancer.

COMBINATION THERAPY

[0391] The present disclosure contemplates the use of compounds of a compound of Formula (I) or a pharmaceutically acceptable salt thereof, a subembodiment thereof, or a pharmaceutical composition as defined herein in combination with one or more active therapeutic agents (e.g., chemotherapeutic agents) or other prophylactic or therapeutic modalities (e.g., radiation). In such combination therapy, the various active agents frequently have different, complementary mechanisms of action. Such combination therapy may be especially advantageous by allowing a dose reduction of one or more of the agents, thereby reducing or eliminating the adverse effects associated with one or more of the agents. Furthermore, such combination therapy may have a synergistic therapeutic or prophylactic effect on the underlying disease, disorder, or condition.

[0392] As used herein, “combination” is meant to include therapies that can be administered separately, for example, formulated separately for separate administration (e.g., as may be provided in a kit), and therapies that can be administered together in a single formulation (i.e., a “co-formulation”).

[0393] In certain embodiments, compounds of Formula (I) or pharmaceutically acceptable salts thereof, subembodiments thereof, or pharmaceutical compositions as defined herein are administered or applied sequentially, e.g., where one agent is administered prior to one or more other agents. In other embodiments, compounds of Formula (I) or pharmaceutically acceptable salts thereof, subembodiments thereof, or pharmaceutical compositions as defined herein are administered simultaneously, e.g., where two or more agents are administered at or about the same time; the two or more agents may be present in two or more separate formulations or combined into a single formulation (i.e., a co-formulation). Regardless of whether the two or more agents are administered sequentially or simultaneously, they are considered to be administered in combination for purposes of the present disclosure.

[0394] The present disclosure also contemplates the use of the compound of Formula (I) or a pharmaceutically acceptable salt thereof, a subembodiment thereof, or a pharmaceutical composition as defined herein in combination with at least one additional therapeutic agent as described herein in order to treat the diseases, disorders and conditions contemplated by the present disclosure.

[0395] The present disclosure also provides a method of treating a disease or disorder in which PRMT5 activity is implicated in a patient, said method comprising administering to said patient (a) a therapeutically effective amount of a compound of Formula (I) or a pharmaceutically acceptable salt thereof, a subembodiment thereof, or a pharmaceutical composition as defined herein and (b) at least one additional therapeutic agent. In some embodiments, the patient is in recognized need of such treatment. In an embodiment, the disease or disorder is cancer.

[0396] The present disclosure also provides a method of treating an MTAP null cancer in a patient comprising administering to the patient a therapeutically effective amount of (a) a compound of Formula (I) or a pharmaceutically acceptable salt thereof, a subembodiment thereof, or a pharmaceutical composition as defined herein and (b) at least one additional therapeutic agent. In some embodiments, the patient is in recognized need of such treatment

[0397] The present disclosure also provides a method of treating a cancer deficient in CDKN2A in a patient comprising administering to the patient (a) a therapeutically effective amount of a compound of Formula (I) or a pharmaceutically acceptable salt thereof, a subembodiment thereof, or a pharmaceutical composition as defined herein and (b) at least one additional therapeutic agent. In some embodiments, the patient is in recognized need of such treatment.

[0398] The present disclosure also provides a method of treating cancer in a patient, wherein the cancer is characterized by a reduction or absence of MTAP gene expression, an absence of the MTAP gene, an absence of MTAP protein, a reduced level of MTAP protein, a reduced function of MTAP protein, or a combination thereof, comprising administering to the patient (a) a therapeutically effective amount of a compound of Formula (I) or a pharmaceutically acceptable salt thereof, a subembodiment thereof, or a pharmaceutical composition as defined herein and (b) at least one additional therapeutic agent. In some embodiments, the patient is in recognized need of such treatment.

[0399] The present disclosure provides methods for treating cancer with (a) a compound of Formula (I) or a pharmaceutically acceptable salt thereof, a subembodiment thereof, or a pharmaceutical composition as defined herein and (b) at least one additional therapeutic or diagnostic agent.

Additional Therapeutic Agents

[0400] The disclosure provides one or more additional therapeutic agents for use with a compound of Formula (I) or a pharmaceutically acceptable salt thereof, a subembodiment thereof and one or more pharmaceutically acceptable excipients. A wide variety of therapeutic agents with anti-cancer activity and methods of making the same are known in the art. Each of these is embraced by this disclosure. In some embodiments, the one or more additional active therapeutic agents are one, two, three, or four additional therapeutic agents. i) Chemotherapeutic Agents

[0401] In an embodiment, the additional therapeutic agent is a chemotherapeutic agent. Chemotherapeutic agents include alkylating agent, microtubule inhibitors, antimetabolites, anti-tumor antibiotics, as well as corticosteroids.

[0402] In some embodiments, the chemotherapeutic agent is an alkylating agent. In some embodiments, the alkylating agent is altretamine, bendamustine, busulfan, improsulfan, piposulfan, procarbazine, mechlorethamine, carmustine, lomustine, semustine chlorambucil, cyclophosphamide, thiotepa, ifosfamide, dacarbazine, temozolomide, or perfosamide. In some embodiments, the alkylating agent is mechlorethamine. In some embodiments, the alkylating agent is perfosamide.

[0403] In an embodiment, the alkylating agent is a platinum-based chemotherapy agent. In some embodiments, the alkylating agent is carboplatin, cisplatin, oxaliplatin, nedaplatin, saraplatin, lobaplatin, or heptaplatin. In some embodiments, the alkylating agent is carboplatin. In some embodiments, the alkylating agent is cisplatin. In some embodiments, the alkylating agent is saraplatin.

[0404] In some embodiments, the chemotherapeutic agent is a microtubule inhibitor. In an embodiment, the microtubule inhibitor is eribulin, ixabepilone, cabazitaxel, enfortumab vedotin, trastuzumab emtansine, tirbanibulin. In some embodiments microtuial inhibitors are plant alkaloids. In some embodiments, the plant alkaloid is a taxane (taxol, paclitaxel and docetaxel), a vinca alkaloid (vinblastine, vincristine, vindesine and vinorelbine), colchicine, podophyllotoxin, or abraxane (protein-bound paclitaxel). In some embodiments, the chemotherapeutic agent is paclitaxel.

[0405] In some embodiments, the chemotherapeutic agent is an antimetabolite. In an embodiment, the antimetabolite is 5-fluorouracil (5-FU), capecitabine, floxuridine, cytarabine, 5-fluorodeoxyuridine, 5-fluorodeoxyuridine monophosphate, cytosine arabinoside, 5-azacytidine, gemcitabine, clofarabine, mercaptopurine, thioguanine, azathioprine, pentostatin, erythrohydroxynonyladenine, fludarabine, cladribine decitabine, Azacitidine, vidaza, or methotrexate. In an embodiment, the antimetabolite is cladribine. In an embodiment, the antimetabolite is clofarabine. In an embodiment, the antimetabolite is cytarabine. In an embodiment, the antimetabolite is gemcitabine. In an embodiment, the antimetabolite is floxuridine.

[0406] In some embodiments, the chemotherapeutic agent is an antitumor antibiotics. In some embodiments, the antitumor antibiotic is bleomycin, dactinomycin, or mitomycin. In some embodiments, the antitumor antibiotic is daunorubicin, doxorubicin, doxil, epirubicin, idarubicin, mitoxantrone, valrubicin.

[0407] In some embodiments, the chemotherapeutic agent is a corticosteroid. In some embodiments, the corticosteroid is prednisone, methylprednisolone, or dexamethasone.

[0408] Examples of chemotherapeutic agents include, but are not limited to, alkylating agents such as thiotepa and cyclosphosphamide; alkyl sulfonates such as busulfan, improsulfan and piposulfan; aziridines such as benzodopa, carboquone, meturedopa, and uredopa; ethylenimines and methylamelamines including altretamine, triethylenemelamine, trietylenephosphoramide, triethylenethiophosphaoramide and trimethylolomelamime; nitrogen mustards such as chiorambucil, chlomaphazine, cholophosphamide, estramustine, ifosfamide, mechlorethamine, mechlorethamine oxide hydrochloride, melphalan, novembichin, phenesterine, prednimustine, trofosfamide, uracil mustard; nitrosureas such as carmustine, chlorozotocin, fotemustine, lomustine, nimustine, ranimustine; antibiotics such as aclacinomysins, actinomycin, authramycin, azaserine, bleomycins, cactinomycin, calicheamicin, carabicin, caminomycin, carzinophilin, chromomycins, dactinomycin, daunorubicin, detorubicin, 6-diazo-5-oxo-L-norleucine, doxorubicin, epirubicin, esorubicin, idarubicin, marcellomycin, mitomycins, mycophenolic acid, nogalamycin, olivomycins, peplomycin, potfiromycin, puromycin, quelamycin, rodorubicin, streptonigrin, streptozocin, tubercidin, ubenimex, zinostatin, zorubicin; anti-metabolites such as methotrexate and 5- fluorouracil (5-FU); folic acid analogs such as denopterin, methotrexate, pteropterin, trimetrexate; purine analogs such as fludarabine, 6-mercaptopurine, thiamiprine, thioguanine; pyrimidine analogs such as ancitabine, azacitidine, 6-azauridine, carmofur, cytarabine, dideoxyuridine, doxifhiridine, enocitabine, floxuridine, 5-FU; androgens such as calusterone, dromostanolone propionate, epitiostanol, mepitiostane, testolactone; anti-adrenals such as aminoglutethimide, mitotane, trilostane; folic acid replenisher such as frolinic acid; aceglatone; aldophosphamide glycoside; aminolevulinic acid; amsacrine; bestrabucil; bisantrene; edatraxate; defofamine; demecolcine; diaziquone; elformithine; elliptinium acetate; etoglucid; gallium nitrate; hydroxyurea; lentinan; lonidamine; mitoguazone; mitoxantrone; mopidamol; nitracrine; pentostatin; phenamet; pirarubicin; podophyllinic acid; 2-ethylhydrazide; procarbazine; razoxane; sizofiran; spirogermanium; tenuazonic acid; triaziquone; 2,2',2"-trichlorotriethylamine; urethan; vindesine; dacarbazine; mannomustine; mitobronitol; mitolactol; pipobroman; gacytosine; arabinoside (Ara-C); cyclophosphamide; thiotepa; taxoids, e.g., paclitaxel and doxetaxel; chlorambucil; gemcitabine; 6-thioguanine; mercaptopurine; methotrexate; platinum and platinum coordination complexes such as cisplatin and carboplatin; vinblastine; etoposide (VP- 16); ifosfamide; mitomycin C; mitoxantrone; vincristine; vinorelbine; navelbine; novantrone; teniposide; daunomycin; aminopterin; xeloda; ibandronate; CPT11; topoisomerase inhibitors; difhioromethylomithine (DMFO); retinoic acid; esperamicins; capecitabine; and pharmaceutically acceptable salts, acids or derivatives of any of the above. In a particular embodiment, compounds of the present disclosure are coadministered with a cytostatic compound selected from the group consisting of cisplatin, doxorubicin, taxol, taxotere and mitomycin C. In a particular embodiment, the cytostatic compound is doxorubicin. Chemotherapeutic agents also include anti-hormonal agents that act to regulate or inhibit hormonal action on tumors such as antiestrogens, including for example tamoxifen, raloxifene, aromatase inhibiting 4(5)-imidazoles, 4-hydroxytamoxifen, trioxifene, keoxifene, onapristone, and toremifene; and antiandrogens such as fhitamide, nilutamide, bicahitamide, enzalutamide, apalutamide, abiraterone acetate, leuprolide, and goserelin; and pharmaceutically acceptable salts, acids or derivatives of any of the above. In certain embodiments, combination therapy comprises administration of a hormone or related hormonal agent. ii) Cell Cycle Checkpoint Inhibitors

[0409] In an embodiment, the additional therapeutic agent is a cell cycle checkpoint inhibitor. In some embodiments, the cell cycle checkpoint inhibitor is KU60019, AZD0156, Ceralasertib, Camonsertib, VE821, AZD7762, SRA737, Rabusertib, Prexasertib, SCH900776, or Adavosertib. In some embodiments, the cell cycle checkpoint inhibitor is KU60019. In some embodiments, the cell cycle checkpoint inhibitor is AZD0156. In some embodiments, the cell cycle checkpoint inhibitor is ceralasertib. In some embodiments, the cell cycle checkpoint inhibitor is camonsertib. In some embodiments, the cell cycle checkpoint inhibitor is VE821. In some embodiments, the cell cycle checkpoint inhibitor is AZD7762. In some embodiments, the cell cycle checkpoint inhibitor is SRA737. In some embodiments, the cell cycle checkpoint inhibitor is rabusertib. In some embodiments, the cell cycle checkpoint inhibitor is prexasertib. In some embodiments, the cell cycle checkpoint inhibitor is SCH900776. In some embodiments, the cell cycle checkpoint inhibitor is adavosertib. iii) Immune Checkpoint Inhibitors

[0410] In an embodiment, the additional therapeutic agent is an immune check point inhibitor. In some embodiments, the immune checkpoint inhibitor is a PD-1/PD-L1 inhibitor, a LAG-3 inhibitor, a CTLA-4 inhibitor, a BTLA inhibitor, a TIM-3 inhibitor, or a TIGIT inhibitor.

[0411] In an embodiment, the PD-1/PD-L1 inhibitor is a PD-1 inhibitor. In an embodiment, the PD-1 inhibitor is nivolumab, pembrolizumab, cemiplimab, dostarlimab, zimberelimab, retifanlitnab, or atezolizumab. In an embodiment, the PD-1 inhibitor is nivolumab. In an embodiment, the PD-1 inhibitor is pembrolizumab. In an embodiment, the PD-1 inhibitor is cemiplimab. In an embodiment, the PD-1 inhibitor is dostarlimab. In an embodiment, the PD-1 inhibitor is zimberelimab. In an embodiment, the PD-1 inhibitor is retifanlimab. In an embodiment, the PD-1 inhibitor is atezolizumab.

[0412] In an embodiment PD-1/PD-L1 inhibitor is a PD-L1 inhibitor. In an embodiment, the PD-L1 inhibitor is avelumab, atezolizumab, or durvalumab. In an embodiment, the PD- L1 inhibitor is avelumab. In an embodiment, the PD-L1 inhibitor is atezolizumab. In an embodiment, the PD-L1 inhibitor is durvalumab. [0413] In some embodiments, the immune checkpoint inhibitor is a LAG-3 inhibitor. In some embodiments, the LAG-3 inhibitor is relatlimab.

[0414] In some embodiments, the immune checkpoint inhibitor is a CTLA-4 inhibitor. In some embodiments, the ipilimumab or tremelimumab

[0415] In some embodiments, the immune checkpoint inhibitor is a BTLA inhibitor.

[0416] In some embodiments, the immune checkpoint inhibitor is a TIM-3 inhibitor. In some embodiments, the TIM-3 inhibitor is sabatolimab, TSR-022 (NCT02817633), MBG453 (NCT02608268), or LY3321367 (NCT03099109). In some embodiments, the immune checkpoint inhibitor is a TIM-3 inhibitor. In some embodiments, the TIM-3 inhibitor is sabatolimab, TSR-022 (NCT02817633), MBG453 (NCT02608268), or LY3321367 (NCT03099109). In some embodiments, the TIM-3 inhibitor is sabatolimab. In some embodiments, the immune checkpoint inhibitor is a TIM-3 inhibitor. In some embodiments, the TIM-3 inhibitor is TSR-022 (NCT02817633). In some embodiments, the TIM-3 inhibitor is MBG453 (NCT02608268). In some embodiments, the TIM-3 inhibitor is LY3321367 (NCT03099109).

[0417] In some embodiments, the immune checkpoint inhibitor is a TIGIT inhibitor. In some embodiments, the TIGIT inhibitor is tiragohimab, domvanalimab, vibostolimab, etigilimab, M6223, or ociperlimab. In some embodiments, the TIGIT inhibitor is tiragolumab. In some embodiments, the TIGIT inhibitor is domvanalimab. In some embodiments, the TIGIT inhibitor is vibostolimab. In some embodiments, the TIGIT inhibitor is etigilimab. In some embodiments, the TIGIT inhibitor is M6223. In some embodiments, the TIGIT inhibitor is ociperlimab. iv) BCL-2 Inhibitors

[0418] In some embodiments, the additional therapeutic agent is a BCL-2 inhibitor. In some embodiments, the BCL-2 inhibitor is venetoclax, navitoclax, oblimersen, obatoclax mesylate, AT-101, subatoclax, maritoclax, gossypol, apogossypol, TW-37, UM 77, or BDA- 366. v) Anti-CD20 therapeutic agent [0419] In some embodiments, the additional therapeutic agent is an anti-CD20 therapeutic agent. In some embodiments, the anti-CD20 therapeutic agent is rituximab, arzerra, gazyva, ibritumomab tiuxetan, obinutuzumab, ofatumumab, riabni, rituxan, ruxience, truxima, zevalin, or tositumomab. vi) Hormonal Therapeutic Agent

[0420] In some embodiments, the additional therapeutic agent is a hormonal therapeutic agent. In some embodiments, the hormonal therapeutic agent is anastrozole, exemestand, letrozole, zoladex, lupon eligard, tamoxifen, raloxifene, goserelin, leuprorelin, fulvestrant, 4- hydroxytamoxifen, trioxifene, keoxifene, onapristone, toremifene; flutamide, nilutamide, bicalutamide, enzalutamide, apalutamide, abiraterone acetate, leuprolide, or goserelin. vii) PARP Inhibitors

[0421] In some embodiments, the additional therapeutic agent is a PARP inhibitor. In some embodiments, the PARP inhibitor is niraparib, rucaparib, olaparib, talazoparib, or veliparib. viii) MAT2A Inhibitors

[0422] In some embodiments, the additional therapeutic agent is a MAT2A inhibitor. In some embodiments, the MAT2A inhibitor is AG-270, . In some embodiments, the MAT2A inhibitor is a compound disclosed in WO2020/123395, the contents of which is incorporated herein by reference for all purposes. In some embodiments, the MAT2A inhibitor is a compound disclosed in WO2018/045071, the contents of which is incorporated herein by reference for all purposes. In some embodiments, the MAT2A inhibitor is a compound disclosed in WO2021/252681, WO2021/252680, WO2021/252679, WO2021/252678, or WO2023/196985, the contents of which are incorporated herein by reference for all purposes. In some embodiments, the MAT2A inhibitor is a compound disclosed in WO2021/1259815, WO2023/066283, WO2024/217502, W02020/139991, W02020/139992, WO2018/045071, WO2018/039972, W02019191470, W02024/002024, or WO2024/217493, the contents of which are incorporated herein by reference for all purposes. In some embodiments, the MAT2A inhibitor is ISM3412 or S095035. In some embodiments, the MAT2A inhibitor is , or, or pharmaceutically acceptable salt thereof.

[0423] In some embodiments, the MAT2A inhibitor is a compound disclosed in WO2022/268180, the contents of which are incorporated herein by reference for all purposes.

[0424] In some embodiments, the MAT2A inhibitor is pharmaceutically acceptable salt thereof. ix) Radiotherapy

[0425] In some embodiments, the additional therapeutic agent is radiation therapy. x) VEGF Inhibitors

[0426] In some embodiments, the additional therapeutic agent is a VEGF inhibitor. In some embodiments, the VEGF inhibitor is Bevacizumab, aflibercept, ranibizumab, sorafenib, dasatinib, sunitinib, nilotinib, pazopanib, pegaptanib, axitinib, lenvatinib, ramucirumab, or regorafenib. xi) Tyrosine Kinase Inhibitors

[0427] In some embodiments, the additional therapeutic agent is a tyrosine kinase inhibitor. In some embodiments, the tyrosine kinase inhibitor is afatinib, cetuximab, imatinib, trastuzumab, gefitinib, dacomitinib, osimertinib, neratinib, almonertinib, brigatinib, icotinib, olmutinib, sorafenib, dasatinib, bosutinib, ponatinib, asciminib, sunitinib, erlotinib, nilotinib, lapatinib, tucatinib, pyrotinib, panitumumab, nimotuzumab, necitumumab, mobocertinib, vandetanib, lenvatinib, pazopanib, mubritinib, fostamatinib, calquence, pertuzumab, acalabrutinib, alectinib, cabozantinib, ceritinib, capmatinib, or crizotinib. xii)mT0R Inhibitors

[0428] In some embodiments, the additional therapeutic agent is an mTOR inhibitor. In some embodiments, the mTOR inhibitor is rapamycin, everolimus, sirolimus, temsirolimus, everolimus, or sirolimus. xiii) AKT Inhibitors

[0429] In some embodiments, the additional therapeutic agent is an ATK inhibitor. In some embodiments, the ATK inhibitor is ipatasertib, mk-2206, perifosine, capivasertib, triciribine, or GSK690693. xiv)CDK Inhibitors

[0430] In some embodiments, the additional therapeutic agent is a CDK inhibitor. In some embodiments, the CDK inhibitor is flavopiridol, roscovitine, RO-3306, dinaciclib, milciclib, palbociclib, ribociclib, abemaciclib, BS-181, DRB, meriolin 3, variolin b, meridianin e, nortopsentins, AZD5438, roniciclib, SNS-032, sorafenib, K03861, THZ531, THZ1, E9, SY- 1365, or seliciclib. In some embodiments, the CDK inhibitor is palbociclib, ribociclib, and abemaciclib. xv) PI3K Inhibitors

[0431] In some embodiments, the additional therapeutic agent is a PI3K inhibitor. In some embodiments, the PI3K inhibitor is idelalisib, alpelisib, leniolisib, duvelisib, or copanlisib. xvi )JAK Inhibitors [0432] In some embodiments, the additional therapeutic agent is a JAK inhibitor. In some embodiments, the JAK inhibitor is tofacitinib, baricitinib, ruxolitinib, upadacitinib, fedratinib, filgotinib, or abrocitinib. xvii) Inhibitors of Cereblon (Ubiquitin Ligase)

[0433] In some embodiments, the additional therapeutic agent is a inhibitor of cereblon. In some embodiments, the inhibitor of cereblon is thalidomide, lenalidomide. xviii) MAPK/ERK Inhibitors

[0434] In some embodiments, the additional therapeutic agent is a MAPK/ERK inhibitor. In some embodiments, the MAPK/ERK inhibitor is vemurafenib, dabrafenib, octreotide, pasireotide, SB590885, GDC0879, LGX818, AZ628, RAF709, binimetinib, L-778, MK2206, pimasertib, rafametinib, salirasib, selumetinib, SML-8-731, tipifamib, lonafamib, trametinib, ulixertinib, WX-554, or cobimetinib. xix)Wnt/fi-catenin Inhibitors

[0435] In some embodiments, the additional therapeutic agent is a Wnt/ -catenin inhibitor. In some embodiments, the Wnt/ -catenin inhibitor is capmatinib, resibufogenin, or isoquercitrin. xx) Proteosome Inhibitors

[0436] In some embodiments, the additional therapeutic agent is a proteosome inhibitor. In some embodiments, the proteosome inhibitor bortezomib, carfilzomib, or ixazomib. xxi)Histone Deacetylase Inhibitors

[0437] In some embodiments, the additional therapeutic agent is a histone deacetylase inhibitor. In some embodiments, the histone deacetylase inhibitor vorinostat, romidepsin, panobinostat, or belinostat. xxii) Recombinant IL-2

[0438] In some embodiments, the additional therapeutic agent is a recombinant IL-2. In some embodiments, the recombinant IL-2 is aldesleukin. xxiii) RANKL Inhibitors

[0439] In some embodiments, the additional therapeutic agent is a RANKL inhibitor. In some embodiments, the RANKL inhibitor is Denosumab or AS2676293. xxiv) B4GALNT1 Inhibitors

[0440] In some embodiments, the additional therapeutic agent is a B4GALNT1 inhibitor.

In some embodiments, the B4GALNT1 inhibitor is Dinutuximab. xxv ) SLAMF7 Inhibitors

[0441] In some embodiments, the additional therapeutic agent is a SLAMF7 inhibitor. In some embodiments, the SLAMF7 inhibitor is elotuzumab. xxvi) IDH2/IDH1 Inhibitors

[0442] In some embodiments, the additional therapeutic agent is a IDH2/IDH1 inhibitor. In some embodiments, the IDH2/IDH1 inhibitor is enasidenib, ivosidenib, AGI-6780, AG- 221, FT-2102, IDH305, GSK 321, or BAY1436032. xxvii) BTK Inhibitors

[0443] In some embodiments, the additional therapeutic agent is a BTK inhibitor. In some embodiments, the BTK inhibitor is ibrutinib, acalabrutinib, zanubrutinib, or pirtobrutinib. xxviii) FLT3 Inhibitors

[0444] In some embodiments, the additional therapeutic agent is a FLT3 inhibitor. In some embodiments, the FLT3 inhibitor is sunitinib, midostaurin, lestaurtinib, KW-2449, crenolanib, or gilteritinib. xxix) PDGFRa Inhibitors

[0445] In some embodiments, the additional therapeutic agent is a PDGFRa inhibitor. In some embodiments, the PDGFRa inhibitor is olaratumab, avapritinib, ayvakit, imatinib, ripretinib, or regorafenib. xxx) Smoothened (Smo) Inhibitors

[0446] In some embodiments, the additional therapeutic agent is a smoothened inhibitor.

In some embodiments, the smoothened inhibitor is sonidegib, itraconazole, or glasdegib. xxxi ) LHRH antagonists or LHRH agonists

[0447] In some embodiments, the additional therapeutic agent is a LHRH antagonist or LHRH agonist. In some embodiments, the LHRH antagonist or LHRH agonist is goserelin, leuprorelin or buserelin. xxxii) Cell Based Therapy [0448] In some embodiments, the additional therapeutic agent is a cell based therapy. In some embodiments, the cell based therapy is tumor-infiltrating lymphocyte (TIL) therapy; engineered t cell receptor (TCR) therapy; chimeric antigen receptor (CAR) T cell therapy; Natural Killer (NK) cell therapy; or sipuleucel-T. xxxiii) 0X40 Inhibitors

[0449] In some embodiments, the additional therapeutic agent is a 0X40 inhibitor. In some embodiments, the 0X40 inhibitor is ivuxolimab, cudarolimab, utomilumab, or INBRX- 106. xxxiv) 41BB ( CD137) Inhibitors

[0450] In some embodiments, the additional therapeutic agent is a 41BB (CD137) inhibitor. In some embodiments, the 41BB (CD137) inhibitor is urelumab. xxxv) VISTA Inhibitors

[0451] In some embodiments, the additional therapeutic agent is a VISTA inhibitor. In some embodiments, the VISTA inhibitor is hmbd-002. xxxvi) CD96 Inhibitors

[0452] In some embodiments, the additional therapeutic agent is a CD96 inhibitor. In some embodiments, the CD96 inhibitor is GSK6097608. xxxvii) TGF P Inhibitors

[0453] In some embodiments, the additional therapeutic agent is a TGF inhibitor. In some embodiments, the TGFp inhibitor is SAR-439459. xxxviii)CDI9 Inhibitors

[0454] In some embodiments, the additional therapeutic agent is a CD 19 inhibitor. In some embodiments, the CD19 inhibitor is tafasitamab, loncastuximab tesirine, or blinatumomab. xxxix) CD30 Inhibitors

[0455] In some embodiments, the additional therapeutic agent is a CD30 inhibitor. In some embodiments, the CD30 inhibitor is brentuximab, vedotin, SGN-30, or MDX-060. xl) CD38 Inhibitors [0456] In some embodiments, the additional therapeutic agent is a CD38 inhibitor. In some embodiments, the CD38 inhibitor is daratumumab, darzalex, isatuximab, or sarclisa. xli) CD39 Inhibitors

[0457] In some embodiments, the additional therapeutic agent is a CD39 inhibitor. In some embodiments, the CD39 inhibitor is purOOl, ES002023, TTX-030, IPH5201, or SRF617. xlii) CD52 Inhibitors

[0458] In some embodiments, the additional therapeutic agent is a CD52 inhibitor. In some embodiments, the CD52 inhibitor is alemtuzumab. xliii) CD73 Inhibitors

[0459] In some embodiments, the additional therapeutic agent is a CD73 inhibitor. In some embodiments, the CD73 inhibitor is oleclumab, PSB- 12379, OP-5244, AB-680, CD73-IN-3, MethADP triammonium, dalutrafusp alfa, BK50164, mupadolimab, uliledlimab, MRS4620, BMS-986179, NZV930, AK119, SYM024, INCA00186, or ORIC-533. xliv) A2AR Inhibitors

[0460] In some embodiments, the additional therapeutic agent is an A2AR inhibitor. In some embodiments, the A2AR inhibitor is istradefylline, vipadenant, CVT-6883, enprofylline, ciforadenant, imaradenant, etrumadenant, NIR178, EOS100850, CS3005, PBF- 999, or INCB 106385. xlv A BR Inhibitors

[0461] In some embodiments, the additional therapeutic agent is an A2BR inhibitor. In some embodiments, the A2BR inhibitor is pbf-1129, QAF805, LAS101057 AB928, ISAM140, or TT-4. xlvi) IDO1 & TDO2 Inhibitors

[0462] In some embodiments, the additional therapeutic agent is an IDO1 or a TDO2 inhibitor. In some embodiments, the IDO1 or TDO2 inhibitor is Indoximod, Epacadostat, Navoximod, PF-06840003, BGS-5777, BMS-986205, LW106, IOM2983, RG-70099, LY- 3381916, NLG-802, or LPM-3480226. xlvii) Arginase Inhibitors [0463] In some embodiments, the additional therapeutic agent is an arginase inhibitor. In some embodiments, the arginase inhibitor is numidargistat, pegzilarginase, or INCB001158. xlviii) B7-H3 Inhibitors

[0464] In some embodiments, the additional therapeutic agent is a B7-H3 inhibitor. In some embodiments, the B7-H3 inhibitor is enoblituzumab, I-Omburtamab, DS-7300, or MGC018. xlix) B7-H4 Inhibitors

[0465] In some embodiments, the additional therapeutic agent is a B7-H4 inhibitor. In some embodiments, the B7-H4 inhibitor is mt-1660, FPA150, or AZD8205.

I) Signal transduction inhibitor (STI)

[0466] As used herein, the term “signal transduction inhibitor” refers to an agent that selectively inhibits one or more steps in a signaling pathway. Examples of signal transduction inhibitors (STIs) useful in methods described herein include, but are not limited to: (i) bcr/abl kinase inhibitors (e.g., GLEEVEC); (ii) epidermal growth factor (EGF) receptor inhibitors, including kinase inhibitors and antibodies; (iii) her-2/neu receptor inhibitors (e.g., HERCEPTIN); (iv) inhibitors of Akt family kinases or the Akt pathway (e.g., rapamycin); (v) cell cycle kinase inhibitors (e.g., flavopiridol); and (vi) phosphatidyl inositol kinase inhibitors. li) Spicing inhibitor sulfonamides (SPLAMs)

[0467] In some embodiments, the additional therapeutic agent is a Spicing inhibitor sulfonamide (SPLAM).

[0468] In some embodiments, the SPLAM is indisulam or E7820.

Hi) Additional Therapeutic Agents

[0469] In some embodiments, the additional therapeutic agent is a monoclonal antibody against a tumor antigen, a complex of a monoclonal antibody and toxin, a T-cell adjuvant, bone marrow transplant, or antigen presenting cells (e.g., dendritic cell therapy).

[0470] In some embodiments, the additional therapeutic agent is a an antibody drug conjugate (ADC) comprising one or more antitumor compound conjugated to an antibody via a linker. In some embodiments, the antibody is a bispecific antibody. In some embodiments, the antibody is a monospecific antibody. A number of ADCs comprising antitumor compounds and methods of making the same are known in the art. Each of these is embraced by this disclosure. In an embodiment, the antitumor compound is an additional therapeutic agent disclosed herein. In an embodiment, the antitumor compound is a chemotherapeutic agent disclosed herein.

[0471] In some embodiments, the additional therapeutic agent is Temozolomide, Pemetrexed, Pegylated liposomal doxorubicin (Doxil), Eribulin (Halaven), Ixabepilone (Ixempra), Protein-bound paclitaxel (Abraxane), Oxaliplatin, Irinotecan, Venatoclax (bcl2 inhibitor), 5-azacytadine, Anti-CD20 therapeutics, such as Rituxan and obinutuzumab, Hormonal agents (anastrozole, exemestand, letrozole, zoladex, lupon eligard), CDK4/6 inhibitors, Palbociclib, Abcmaciclib, CPI (Avelumab, Cemiplimab-rwlc, and Bevacizumab).

DOSING

[0472] A compound of Formula (I) or a pharmaceutically acceptable salt thereof, a subembodiment thereof, or a pharmaceutical composition as defined herein may be administered to a subject in an amount that is dependent upon, for example, the goal of administration (e.g., the degree of resolution desired); the age, weight, sex, and health and physical condition of the subject to which the formulation is being administered; the route of administration; and the nature of the disease, disorder, condition or symptom thereof. The dosing regimen may also take into consideration the existence, nature, and extent of any adverse effects associated with the agent(s) being administered.

[0473] An effective dose (ED) is the dose or amount of an agent that produces a therapeutic response or desired effect in some fraction of the subjects taking it. The “median effective dose” or ED50 of an agent is the dose or amount of an agent that produces a therapeutic response or desired effect in 50% of the population to which it is administered. Although the ED50 is commonly used as a measure of reasonable expectance of an agent’s effect, it is not necessarily the dose that a clinician might deem appropriate taking into consideration all relevant factors. Thus, in some situations the effective amount is more than the calculated ED50, in other situations the effective amount is less than the calculated ED50, and in still other situations the effective amount is the same as the calculated ED50.

Il l ROUTES OF ADMINISTRATION

[0474] A compound of Formula (I) or a pharmaceutically acceptable salt thereof, a subembodiment thereof, or a pharmaceutical composition as defined herein comprising this compound may be administered to a patient by any convenient route of administration, whether systemically/peripherally or topically (i.e., at the site of desired action).

[0475] Routes or administration include, but are not limited to, oral (e.g., by ingestion); buccal; sublingual; transdermal (including, e.g., by a patch, plaster, etc.); transmucosal (including, e.g., by a patch, plaster, etc.); intranasal (e.g., by nasal spray); ocular (e.g., by eyedrops); pulmonary (e.g., by inhalation or insufflation therapy using e.g., via an aerosol, e.g., through the mouth or nose); rectal (e.g., by suppository or enema); vaginal (e.g., by pessary); parenteral, for example, by injection, including subcutaneous, intradermal, intramuscular, intravenous, intra-arterial, intracardiac, intrathecal, intraspinal, intracapsular, subcapsular, intraorbital, intraperitoneal, intratracheal, subcuticular, intraarticular, subarachnoid, and intrastemal; by implant of a depot or reservoir, for example, subcutaneously or intramuscularly. Some embodiments of the present invention contemplate oral administration.

NON-LIMITING EXEMPLARY EMBODIMENTS

[0476] The compounds of the current application can be further described by the following non-limiting embodiments: Embodiments 1 to 156; and Embodiments IB to 11 IB.

[0477] Embodiment 1. A compound of Formula (I): or a pharmaceutically acceptable salt thereof, wherein

X¹ is C(R^laR^lb), O, or NR¹;

X² is C(R^2aR^2b), O, or NR²;

X³ is C(R^3aR^3b), O, or NR³;

X⁴ is C(R^4aR^4b), O, NR⁴, S, S(O), or S(O)₂;

X⁵ is C(R^5aR^5b), O, NR⁵, S, S(O), or S(O)₂;

X⁶ is C(R^6aR^6b), O, NR⁶, S, S(O), or S(O)₂; R¹, R², and R³ are each independently H or Ci-4 alkyl;

R⁴, R⁵, and R⁶ are each independently H, C1.4 alkyl, or C1.4 hydroxyalkyl;

R^4a , R^4b, R^5a,R^5b, R^6a, and R^6b are each independently H, C1-4 alkyl, C1-4 haloalkyl, CM hydroxyalkyl, C1-4 haloalky 1(OH); ring A is heterocycloalkyl comprising 4 to 7 ring members with at least 1 nitrogen atom ring vertex, and 0 to 2 additional heteroatoms as ring vertices, wherein each heteroatom is independently N, O, S, S(O), or S(O)2; ring B is Cg-io aryl or heteroaryl comprising 5 to 10 ring members with 1 to 4 heteroatom ring vertices, wherein each heteroatom is independently N, O, or S; p is 0, 1, 2, or 3; q is 0, 1, 2, or 3; each R⁷ is independently C1-6 alkyl, C1-6 haloalkyl, halo, C1-6 alkoxy, C1-6 haloalkoxy, -C(O)Ci-₆ alkyl, -C(O)Ci-₆ haloalkyl, -C(O)OCi-₆ alkyl, or -C(O)OCi-₆ haloalkyl; each R⁸ is independently C1-6 alkyl, C1-6 haloalkyl, halo, C1-6 alkoxy, C1-6 haloalkoxy, - C(O)Ci-₆ alkyl, -C(O)Ci-₆ haloalkyl, -C(O)OCi-₆ alkyl, -C(O)OCi-₆ haloalkyl, or heterocycloalkyl comprising 4 to 6 ring members with 1 to 3 heteroatom ring vertices, wherein each heteroatom is independently N, O, or S, and wherein the heterocycloalkyl is substituted with 0, 1, or 2 R^8a; each R^8a is independently C1.4 alkyl, halo, or C1.4 haloalkyl; alternatively, one R⁷ attached to ring A and one R⁸ attached to ring B combine to form ring C comprising C4-7 cycloalkyl or heterocycloalkyl comprising 4 to 7 ring members with 1 to 3 heteroatom ring vertices, wherein each heteroatom is independently N, O, S, S(O), or S(O)₂, wherein ring C is substituted with 0, 1, 2, or 3 R^7a, and ring A, ring B, and ring C form a fused tricyclic moiety; each R^7a is independently C1-4 alkyl, halo, or C1-4 haloalkyl; alternatively, two R^7a groups attached to the same carbon atom combine to form oxo; and R⁹ is H, Ci-4 alkyl, halo, or C1-4 haloalkyl.

[0478] Embodiment 2. The compound or a pharmaceutically acceptable salt thereof of embodiment 1, wherein X¹ is C(R^laR^lb) or NR¹.

[0479] Embodiment 3. The compound or a pharmaceutically acceptable salt thereof of embodiment 1 or 2, wherein X¹ is NR¹. [0480] Embodiment 4. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments 1 to 3, wherein R¹ is H or methyl.

[0481] Embodiment 5. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments 1 to 3, wherein R¹ is H.

[0482] Embodiment 6. The compound or a pharmaceutically acceptable salt thereof of embodiment 1 or 2, wherein X¹ is C(R^laR^lb).

[0483] Embodiment 7. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments 1, 2, and 6, wherein R^la and R^lb are each independently H, methyl, ethyl, fluoro, chloro, or bromo.

[0484] Embodiment 8. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments 1, 2, and 6, wherein R^la and R^lb are each independently H, methyl, fluoro, chloro, or trifluoromethyl.

[0485] Embodiment 9. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments 1, 2, and 6, wherein R^la and R^lb are each H.

[0486] Embodiment 10. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments 1, 2, and 6, wherein R^la is methyl, and R^lb is H.

[0487] Embodiment 11. The compound or a pharmaceutically acceptable salt thereof of 1, wherein X¹ is O.

[0488] Embodiment 12. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments 1 to 11, wherein X² is C(R^2aR^2b) or O.

[0489] Embodiment 13. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments 1 to 11, wherein X² is O.

[0490] Embodiment 14. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments 1 to 11, wherein X² is C(R^2aR^2b).

[0491] Embodiment 15. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments 1 to 11 and 14, wherein R^2a and R^2b are each independently H, methyl, ethyl, fluoro, chloro, or bromo. [0492] Embodiment 16. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments 1 to 11 and 14, wherein R^2a and R^2b are each independently H, methyl, fluoro, chloro, or trifluoromethyl.

[0493] Embodiment 17. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments 1 to 11 and 14, wherein R^2a and R^2b are each H.

[0494] Embodiment 18. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments 1 to 11 and 14, wherein R^2a is methyl, and R^2b is H.

[0495] Embodiment 19. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments 1 to 18, wherein X³ is C(R^3aR^3b) or NR³.

[0496] Embodiment 20. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments 1 to 19, wherein X³ is NR³.

[0497] Embodiment 21. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments 1 to 20, wherein R³ is H or methyl.

[0498] Embodiment 22. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments 1 to 19, wherein X³ is C(R^3aR^3b).

[0499] Embodiment 23. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments 1 to 19 and 22, wherein R^3a and R^3b are each independently H, methyl, ethyl, fluoro, chloro, or bromo.

[0500] Embodiment 24. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments 1 to 19 and 22, wherein R^3a and R^3b are each independently H, methyl, fluoro, chloro, or trifluoromethyl.

[0501] Embodiment 25. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments 1 to 19 and 22, wherein R^3a and R^3b are each H.

[0502] Embodiment 26. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments 1 to 19 and 22, wherein R^3a is methyl, and R^3b is H.

[0503] Embodiment 27. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments 1 to 18, wherein X³ is O.

[0504] Embodiment 28. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments 1 to 27, wherein X⁴ is C(R^4aR^4b), O, or NR⁴. [0505] Embodiment 29. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments 1 to 27, wherein X⁴ is O.

[0506] Embodiment 30. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments 1 to 27, wherein X⁴ is NR⁴.

[0507] Embodiment 31. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments 1 to 28 and 30, wherein R⁴ is H or methyl.

[0508] Embodiment 32. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments 1 to 28 and 30, wherein R⁴ is H.

[0509] Embodiment 33. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments 1 to 27, wherein X⁴ is C(R^4aR^4b).

[0510] Embodiment 34. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments 1 to 28 and 33, wherein R^4a and R^4b are each independently H, methyl, ethyl, fluoro, chloro, or bromo.

[0511] Embodiment 35. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments 1 to 28 and 33, wherein R^4a and R^4b are each independently H, methyl, fluoro, chloro, or trifluoromethyl.

[0512] Embodiment 36. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments 1 to 28 and 33, wherein R^4a and R^4b are each H.

[0513] Embodiment 37. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments 1 to 28 and 33, wherein R^4a is methyl, and R^4b is H.

[0514] Embodiment 38. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments 1 to 37, wherein X⁵ is C(R^5aR^5b), O, or NR⁵.

[0515] Embodiment 39. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments 1 to 37, wherein X⁵ is O.

[0516] Embodiment 40. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments 1 to 37, wherein X⁵ is NR⁵.

[0517] Embodiment 41. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments 1 to 38 and 40, wherein R⁵ is H or methyl. [0518] Embodiment 42. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments 1 to 38 and 40, wherein R⁵ is H.

[0519] Embodiment 43. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments 1 to 37, wherein X⁵ is C(R^5aR^5b).

[0520] Embodiment 44. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments 1 to 38 and 43, wherein R^5a and R^5b are each independently H, methyl, ethyl, fluoro, chloro, or bromo.

[0521] Embodiment 45. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments 1 to 38 and 43, wherein R^5a and R^5b are each independently H, methyl, fluoro, chloro, or trifluoromethyl.

[0522] Embodiment 46. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments 1 to 38 and 43, wherein R^5a and R^5b are each H.

[0523] Embodiment 47. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments 1 to 38 and 43, wherein R^5a is methyl, and R^5b is H.

[0524] Embodiment 48. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments 1 to 47, wherein X⁶ is C(R^6aR^6b), O, NR⁶.

[0525] Embodiment 49. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments 1 to 47, wherein X⁶ is O.

[0526] Embodiment 50. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments 1 to 47, wherein X⁶ is NR⁶.

[0527] Embodiment 51. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments 1 to 48 and 50, wherein R⁶ is H or methyl.

[0528] Embodiment 52. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments 1 to 48 and 50, wherein R⁶ is H.

[0529] Embodiment 53. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments 1 to 47, wherein X⁶ is C(R^6aR^6b).

[0530] Embodiment 54. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments 1 to 48 and 53, wherein R^6a and R^6b are each independently H, methyl, ethyl, fluoro, chloro, or bromo. [0531] Embodiment 55. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments 1 to 48 and 53, wherein R^6a and R^6b are each independently H, methyl, fluoro, chloro, or trifluoromethyl.

[0532] Embodiment 56. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments 1 to 48 and 53, wherein R^6a and R^6b are each H.

[0533] Embodiment 57. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments 1 to 48 and 53, wherein R^6a is methyl, and R^6b is H.

[0534] Embodiment 58. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments 1 to 57, wherein ring A is heterocycloalkyl comprising 4 to 6 ring members with at least 1 nitrogen atom ring vertex, and 0 to 2 additional heteroatoms as ring vertices, wherein each heteroatom is independently N, O, or S.

[0535] Embodiment 59. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments 1 to 57, wherein ring A is heterocycloalkyl comprising 4 to 6 ring members with at least 1 nitrogen atom ring vertex, and 0 to 1 additional heteroatoms as ring vertices, wherein each heteroatom is independently N, O, or S.

[0536] Embodiment 60. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments 1 to 57, wherein ring A is pyrrolidinyl, piperidinyl, piperazinyl, or morpholinyl.

[0537] Embodiment 61. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments 1 to 57, wherein ring A is piperidinyl, piperazinyl, or morpholinyl.

[0538] Embodiment 62. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments 1 to 57, wherein ring A is piperidinyl, substituted with 1 or 2 R⁷.

[0539] Embodiment 63. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments 1 to 57, wherein ring A is morpholinyl, substituted with 1 or 2 R⁷.

[0540] Embodiment 64. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments 1 to 63, wherein R⁷ is Ci-6 alkyl, Ci-6 haloalkyl, halo, Ci-6 alkoxy, or Ci-6 haloalkoxy.

[0541] Embodiment 65. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments 1 to 63, wherein R⁷ is Ci-4 alkyl, Ci-4 haloalkyl, or halo. [0542] Embodiment 66. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments 1 to 63, wherein R⁷ is methyl, ethyl, fluoro, chloro, bromo, fluoromethyl, difluoromethyl, or trifluoromethyl.

[0543] Embodiment 67. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments 1 to 63, wherein R⁷ is methyl.

[0544] Embodiment 68. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments 1 to 67, having Formula (la) wherein, ring B is phenyl or heteroaryl comprising 5 to 6 ring members with 1 to 3 heteroatom ring vertices, wherein each heteroatom is independently N, O, or S; p is 0, 1 or 2; q is 0, 1, or 2; and ring C is fused to (a) two adjacent ring vertices of ring A and (b) two adjacent ring vertices of ring B, and comprises C4-7 cycloalkyl or heterocycloalkyl comprising 4 to 7 ring members with 1 to 3 heteroatom ring vertices, wherein each heteroatom is independently N, O, S, S(O), or S(O)₂.

[0545] Embodiment 69. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments 1 to 67, having Formula (Ial-1): wherein,

X^a is O, CH₂, or CHR⁷; p is 0 or 1; q is 0, 1, or 2; and ring C is C4-7 cycloalkyl or heterocycloalkyl comprising 4 to 7 ring members with 1 to 3 heteroatom ring vertices, wherein each heteroatom is independently N, O, S, S(O), or S(O)₂.

[0546] Embodiment 70. The compound or a pharmaceutically acceptable salt thereof of embodiments 68 or 69, wherein ring C is C4-7 cycloalkyl substituted with 0, 1, 2, or 3 R^7a.

[0547] Embodiment 71. The compound or a pharmaceutically acceptable salt thereof of embodiments 68 or 69, wherein ring C is C4-6 cycloalkyl substituted with 0, 1, 2, or 3 R^7a.

[0548] Embodiment 72. The compound or a pharmaceutically acceptable salt thereof of embodiments 68 or 69, wherein ring C is C5-6 cycloalkyl substituted with 0, 1, or 2 R^7a.

[0549] Embodiment 73. The compound or a pharmaceutically acceptable salt thereof of embodiments 68 or 69, wherein ring C is C6 cycloalkyl substituted with 0, 1, or 2 R^7a.

[0550] Embodiment 74. The compound or a pharmaceutically acceptable salt thereof of embodiments 68 or 69, wherein ring C is C5 cycloalkyl substituted with 0, 1, or 2 R^7a.

[0551] Embodiment 75. The compound or a pharmaceutically acceptable salt thereof of embodiments 68 or 69, wherein ring C is heterocycloalkyl comprising 4 to 7 ring members with 1 to 3 heteroatom ring vertices, wherein each heteroatom is independently N, O, S, S(O), or S(O)₂, wherein ring C is substituted with 0, 1, 2, or 3 R^7a.

[0552] Embodiment 76. The compound or a pharmaceutically acceptable salt thereof of embodiments 68 or 69, wherein ring C is heterocycloalkyl comprising 4 to 6 ring members with 1 to 2 heteroatom ring vertices, wherein each heteroatom is independently N, O, S, S(O), or S(O)₂, wherein ring C is substituted with 0, 1, 2, or 3 R^7a.

[0553] Embodiment 77. The compound or a pharmaceutically acceptable salt thereof of embodiments 68 or 69, wherein ring C is heterocycloalkyl comprising 5 to 6 ring members with 1 to 2 heteroatom ring vertices, wherein each heteroatom is independently N, O, or S, S(O), or S(O)₂, wherein ring C is substituted with 0, 1, 2, or 3 R^7a.

[0554] Embodiment 78. The compound or a pharmaceutically acceptable salt thereof of embodiments 68 or 69, wherein ring C is heterocycloalkyl comprising 5 ring members with 1 to 2 heteroatom ring vertices, wherein each heteroatom is independently N, O, or S, wherein ring C is substituted with 0, 1, or 2 R^7a. [0555] Embodiment 79. The compound or a pharmaceutically acceptable salt thereof of embodiments 68 or 69, wherein ring C is heterocycloalkyl comprising 6 ring members with 1 to 2 heteroatom ring vertices, wherein each heteroatom is independently N, O, or S, wherein ring C is substituted with 0, 1, 2, or 3 R^7a.

[0556] Embodiment 80. The compound or a pharmaceutically acceptable salt thereof of embodiments 68 or 69, wherein ring C is heterocycloalkyl comprising 6 ring members with 1 to 2 heteroatom ring vertices, wherein each heteroatom is independently N, O, S, S(O), or S(O)₂, wherein ring C is substituted with 0, 1, 2, or 3 R^7a.

[0557] Embodiment 81. The compound or a pharmaceutically acceptable salt thereof of embodiments 68 or 69, wherein ring C is tetrahydropyranyl substituted with 0, 1, or 2 R^7a.

[0558] Embodiment 82. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments 1 to 67, having Formula (Ia2-1): wherein,

X^a is absent, O, CH₂, or CHR⁷;

X^7a is absent, O or CH₂, or CHR^7a;

X^7b is absent, O or CH₂, or CHR^7a; p is 0, 1 or 2; and q is 0, 1, or 2.

[0559] Embodiment 83. The compound or a pharmaceutically acceptable salt thereof of embodiment 82, wherein

X^a is O, CH₂, or CHR⁷;

X^7a is O or CH₂, or CHR^7a;

X^7b is O or CH₂, or CHR^7a; p is 0, 1 or 2; and q is 0, 1, or 2. [0560] Embodiment 84. The compound or a pharmaceutically acceptable salt thereof of embodiment 82 or 83, wherein X^7a is O, and X^7b is CH2.

[0561] Embodiment 85. The compound or a pharmaceutically acceptable salt thereof of embodiment 82 or 83, wherein X^7a is CH2, and X^7b is O.

[0562] Embodiment 86. The compound or a pharmaceutically acceptable salt thereof of embodiment 82 or 83, wherein X^7a is CH2, and X^7b is CH2.

[0563] Embodiment 87. The compound or a pharmaceutically acceptable salt thereof of embodiment 82, wherein X^7a is absent, and X^7b is CH2.

[0564] Embodiment 88. The compound or a pharmaceutically acceptable salt thereof of embodiment 82, wherein X^7a is absent, and X^7b is O.

[0565] Embodiment 89. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments 1 to 88, wherein R^7a is C1-4 alkyl, halo, or C1-4 haloalkyl.

[0566] Embodiment 90. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments 1 to 88, wherein R^7a is methyl, ethyl, fluoro, chloro, bromo, fluoromethyl, difluoromethyl, or trifluoromethyl.

[0567] Embodiment 91. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments 1 to 88, wherein R^7a is methyl, fluoro, chloro, or trifluoromethyl

[0568] Embodiment 92. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments 1 to 88, wherein two R^7a groups attached to the same carbon atom combine to form oxo.

[0569] Embodiment 93. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments 1 to 92, wherein each R⁸ is independently C1-6 alkyl, Ci-6 haloalkyl, halo, C1-6 alkoxy, or C1-6 haloalkoxy.

[0570] Embodiment 94. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments 1 to 92, wherein each R⁸ is independently C1-6 alkyl, C1-6 haloalkyl, or halo.

[0571] Embodiment 95. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments 1 to 92, wherein each R⁸ is independently methyl, ethyl, fluoro, chloro, bromo, fluoromethyl, difluoromethyl, or trifluoromethyl. [0572] Embodiment 96. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments 1 to 92, wherein each R⁸ is independently bromo or trifluoromethyl.

[0573] Embodiment 97. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments 1 to 67, wherein the moiety has the formula:

[0574] Embodiment 98. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments 1 to 67, having Formula (lb) wherein,

[0575] Embodiment 99. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments 1 to 98, wherein p is 1.

[0576] Embodiment 100. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments 1 to 98, wherein p is 2. [0577] Embodiment 101. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments 1 to 100, wherein q is 0.

[0578] Embodiment 102. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments 1 to 100, wherein q is 1 .

[0579] Embodiment 103. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments 1 to 100, wherein q is 2.

[0580] Embodiment 104. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments 1 to 67, having Formula (Ibl)

[0581] Embodiment 105. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments 1 to 67 and 98 to 104, wherein each R⁸ is independently Ci-6 alkyl, Ci-6 haloalkyl, halo, Ci-6 alkoxy, Ci-6 haloalkoxy, or heterocycloalkyl comprising 4 to 6 ring members with 1 to 3 heteroatom ring vertices, wherein each heteroatom is independently N, O, or S, and wherein the heterocycloalkyl is substituted with 0, 1, or 2 R^8a.

[0582] Embodiment 106. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments 1 to 67 and 98 to 104, wherein each R⁸ is independently Ci-4 alkyl, Ci-4 haloalkyl, halo, or heterocycloalkyl comprising 4 to 6 ring members with 1 to 3 heteroatom ring vertices, wherein each heteroatom is independently N, O, or S, and wherein the heterocycloalkyl is substituted with 0, 1, or 2 R^8a.

[0583] Embodiment 107. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments 1 to 67 and 98 to 104, wherein each R⁸ is independently heterocycloalkyl comprising 4 to 6 ring members with 1 to 3 heteroatom ring vertices, wherein each heteroatom is independently N, O, or S, and wherein the heterocycloalkyl is substituted with 0, 1, or 2 R^8a. [0584] Embodiment 108. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments 1 to 67 and 98 to 104, wherein each R⁸ is independently pyrrolidinyl, tetrahydrofuranyl, piperidinyl, piperazinyl, or morpholinyl substituted with 0, 1, or 2 R^8a.

[0585] Embodiment 109. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments 1 to 67 and 98 to 104, wherein each R⁸ is piperidinyl substituted with 0, 1, or 2 R^8a.

[0586] Embodiment 110. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments 1 to 67 and 98 to 109, wherein each R^8a is C1-4 alkyl.

[0587] Embodiment 111. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments 1 to 67 and 98 to 109, wherein each R^8a is independently methyl, ethyl, fluoro, chloro, bromo, fluoromethyl, difluoromethyl, or trifluoromethyl.

[0588] Embodiment 112. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments 1 to 67, and 98 to 109, wherein each R^8a is methyl.

[0589] Embodiment 113. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments 1 to 67, wherein the moiety

[0590] Embodiment 114. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments 1 to 113, wherein R⁹ is H, methyl, ethyl, fluoro, chloro, bromo, fluoromethyl, difluoromethyl, or trifluoromethyl. [0591] Embodiment 115. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments 1 to 113, wherein R⁹ is H, methyl, fluoro, chloro, or trifluoromethyl.

[0592] Embodiment 116. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments 1 to 113, wherein R⁹ is H.

[0593] Embodiment 117. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments 1 to 113, wherein R⁹ is methyl.

[0594] Embodiment 118. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments 1 to 113, wherein R⁹ is fluoro.

[0595] Embodiment 119. The compound or a pharmaceutically acceptable salt thereof of any embodiment 1, wherein the compound is selected from Examples 1 to 8.

[0596] Embodiment 120. A pharmaceutical composition comprising a compound or a pharmaceutically acceptable salt thereof of any one of embodiments 1 to 119, and a pharmaceutically acceptable excipient.

[0597] Embodiment 121. A method for treating a disease treatable by inhibition of protein arginine N-methyltransferase 5 (PRMT5) in a patient comprising administering to the patient a therapeutically effective amount of a compound or a pharmaceutically acceptable salt thereof of any one of embodiments 1 to 119, or a pharmaceutical composition of embodiment 120.

[0598] Embodiment 122. The method of embodiment 121, wherein the disease is cancer.

[0599] Embodiment 123. A method of treating an MTAP null cancer in a patient comprising administering to the patient a therapeutically effective amount of a compound or a pharmaceutically acceptable salt thereof of any one of embodiments 1 to 119, or a pharmaceutical composition of embodiment 120.

[0600] Embodiment 124. A method for treating a cancer in a patient, wherein the cancer is characterized by a reduction or absence of MTAP gene expression, the absence of the MTAP gene, absence of MTAP protein, reduced level of MTAP protein, or reduced function of MTAP protein, comprising administering to the patient a therapeutically effective amount of a compound or pharmaceutically acceptable salt thereof of any one of embodiments 1 to 119, or a pharmaceutical composition of embodiment 120. [0601] Embodiment 125. A method of treating cancer in a patient comprising administering to the patient a therapeutically effective amount of a compound or a pharmaceutically acceptable salt thereof of any one of embodiments 1 to 119, or a pharmaceutical composition of embodiment 120.

[0602] Embodiment 126. The method of any one of embodiments 122 to 125, wherein the cancer is an MTAP-deficient cancer, MTA-accumulating cancer, or a combination thereof.

[0603] Embodiment 127. The method of embodiment 122 or 126, wherein the cancer is deficient in CDKN2A.

[0604] Embodiment 128. The method of any one of embodiments 122 to 127, wherein the cancer is a solid tumor.

[0605] Embodiment 129. The method of embodiment 128, wherein the solid tumor is malignant.

[0606] Embodiment 130. The method of any one of embodiments 122 to 129, wherein the patient is in recognized need of such treatment.

[0607] Embodiment 131. The method of any one of embodiments 122 to 130, wherein the cancer is selected from the group consisting of biliary tract cancer, glioblastoma, ovarian cancer, malignant peripheral nerve sheath tumors (MPNST), colon cancer, esophageal cancer (e.g., esophageal squamous cell carcinoma or esophageal adenocarcinoma), gastric cancer, bladder cancer ( e.g., bladder urothelial carcinoma, gallbladder cancer), pancreatic cancer (e.g., pancreatic adenocarcinoma), mesothelioma, melanoma, lung cancer (e.g., non-small cell lung cancer (NSCLC; e.g., lung squamous or lung adenocarcinoma)), astrocytoma, undifferentiated pleiomorphic sarcoma, lymphoma (e.g., diffuse large B-cell lymphoma (DLBCL)), leukemia, head and neck cancer (e.g., head and neck squamous cell carcinoma), stomach adenocarcinoma, myxofibrosarcoma, cholangiosarcoma, cancer of the brain, stomach, kidney, breast, endometrium, urinary tract, liver, soft tissue, pleura and large intestine or sarcoma.

[0608] Embodiment 132. The method of any one of embodiments 122 to 130, wherein the cancer is selected from the group consisting of leukemia, esophageal cancer, glioma, melanoma, pancreatic, non-small cell lung cancer, bladder cancer, astrocytoma, osteosarcoma, head and neck cancer, myxoid chondrosarcoma, ovarian cancer, endometrial cancer, breast cancer, soft tissue sarcoma, non-Hodgkin lymphoma and mesothelioma.

[0609] Embodiment 133. The method of any one of embodiments 122 to 130, wherein the cancer is selected from the group consisting of non-small cell lung cancer (squamous and adenocarcinoma), urothelial cancer (bladder and upper urinary tract), esophageal cancer, and gastric cancer.

[0610] Embodiment 134. A compound or a pharmaceutically acceptable salt thereof of any one of embodiments 1 to 119, or a pharmaceutical composition of embodiment 120, for use in therapy.

[0611] Embodiment 135. A compound or a pharmaceutically acceptable salt thereof of any one of embodiments 1 to 119, or a pharmaceutical composition of embodiment 120, for use in the treatment cancer.

[0612] Embodiment 136. The compound or the pharmaceutically acceptable salt thereof or the pharmaceutical composition of embodiment 135, wherein said cancer is an MTAP- deficient cancer, MTA-accumulating cancer, or a combination thereof.

[0613] Embodiment 137. The compound or the pharmaceutically acceptable salt thereof or the pharmaceutical composition of embodiment 135 or 136, wherein said cancer is deficient in CDKN2A.

[0614] Embodiment 138. The compound or the pharmaceutically acceptable salt thereof or the pharmaceutical composition of any one of embodiments 135 to 137, wherein said cancer is an MTAP null cancer.

[0615] Embodiment 139. The compound or the pharmaceutically acceptable salt thereof or the pharmaceutical composition of any one of embodiments 135 to 137, wherein said cancer is characterized by a reduction or absence of MTAP gene expression, the absence of the MTAP gene, absence of MTAP protein, reduced level of MTAP protein, or reduced function of MTAP protein.

[0616] Embodiment 140. The compound or the pharmaceutically acceptable salt thereof or the pharmaceutical composition of any one of embodiments 135 to 139, wherein said cancer is a solid tumor. [0617] Embodiment 141. The compound or the pharmaceutically acceptable salt thereof or the pharmaceutical composition of embodiment 140, wherein the solid tumor is malignant.

[0618] Embodiment 142. The compound or the pharmaceutically acceptable salt thereof or the pharmaceutical composition of any one of embodiments 135 to 141, wherein said cancer is biliary tract cancer, glioblastoma, ovarian cancer, malignant peripheral nerve sheath tumors (MPNST), colon cancer, esophageal cancer (e.g., esophageal squamous cell carcinoma or esophageal adenocarcinoma), gastric cancer, bladder cancer (e.g., bladder urothelial carcinoma, gallbladder cancer), pancreatic cancer (e.g., pancreatic adenocarcinoma), mesothelioma, melanoma, lung cancer e.g., non-small cell lung cancer (NSCLC; e.g., lung squamous or lung adenocarcinoma)), astrocytoma, undifferentiated pleiomorphic sarcoma, lymphoma (e.g., diffuse large B-cell lymphoma (DLBCL)), leukemia, head and neck cancer (e.g., head and neck squamous cell carcinoma), stomach adenocarcinoma, myxofibrosarcoma, cholangiosarcoma, cancer of the brain, stomach, kidney, breast, endometrium, urinary tract, Ever, soft tissue, pleura and large intestine or sarcoma.

[0619] Embodiment 143. The compound or the pharmaceutically acceptable salt thereof or the pharmaceutical composition of any one of embodiments 135 to 141, wherein said cancer is leukemia, esophageal cancer, glioma, melanoma, pancreatic, non-small cell lung cancer, bladder cancer, astrocytoma, osteosarcoma, head and neck cancer, myxoid chondrosarcoma, ovarian cancer, endometrial cancer, breast cancer, soft tissue sarcoma, nonHodgkin lymphoma or mesothelioma.

[0620] Embodiment 144. Use of a compound or a pharmaceutically acceptable salt thereof of any one of embodiments 1 to 119, or a pharmaceutical composition of embodiment 120, in the manufacture of a medicament for use in therapy.

[0621] Embodiment 145. Use of a compound or a pharmaceutically acceptable salt thereof of any one of embodiments 1 to 119, or a pharmaceutical composition of embodiment 120, in the manufacture of a medicament for use in the treatment of cancer.

[0622] Embodiment 146. The use of embodiment 145, wherein said cancer is an MTAP- deficient cancer, MTA-accumulating cancer, or a combination thereof.

[0623] Embodiment 147. The use of embodiment 145 or 146, wherein said cancer is deficient in CDKN2A. [0624] Embodiment 148. The use of any one of embodiments 145 to 147, wherein said cancer is an MTAP null cancer.

[0625] Embodiment 149. The use of any one of embodiments 145 to 147, wherein said cancer is characterized by a reduction or absence of MTAP gene expression, the absence of the MTAP gene, absence of MTAP protein, reduced level of MTAP protein, or reduced function of MTAP protein.

[0626] Embodiment 150. The use of any one of embodiments 145 to 149, wherein said cancer is a solid tumor.

[0627] Embodiment 151. The use of embodiment 150, wherein said solid tumor is malignant.

[0628] Embodiment 152. The use of any one of embodiments 145 to 151, wherein said cancer is biliary tract cancer, glioblastoma, ovarian cancer, malignant peripheral nerve sheath tumors (MPNST), colon cancer, esophageal cancer (e.g., esophageal squamous cell carcinoma or esophageal adenocarcinoma), gastric cancer, bladder cancer (e.g., bladder urothelial carcinoma, gallbladder cancer), pancreatic cancer ( e.g., pancreatic adenocarcinoma), mesothelioma, melanoma, lung cancer (e.g., non-small cell lung cancer (NSCLC; e.g., lung squamous or lung adenocarcinoma)), astrocytoma, undifferentiated pleiomorphic sarcoma, lymphoma (e.g., diffuse large B-cell lymphoma (DLBCL)), leukemia, head and neck cancer (e.g., head and neck squamous cell carcinoma), stomach adenocarcinoma, myxofibrosarcoma, cholangiosarcoma, cancer of the brain, stomach, kidney, breast, endometrium, urinary tract, liver, soft tissue, pleura and large intestine or sarcoma.

[0629] Embodiment 153. The use of any one of embodiments 145 to 151, wherein said cancer is leukemia, esophageal cancer, glioma, melanoma, pancreatic, non-small cell lung cancer, bladder cancer, astrocytoma, osteosarcoma, head and neck cancer, myxoid chondrosarcoma, ovarian cancer, endometrial cancer, breast cancer, soft tissue sarcoma, nonHodgkin lymphoma or mesothelioma.

[0630] Embodiment 154. A method of inhibiting protein arginine N-methyltransferase 5 (PRMT5) in vivo in a patient, said method comprising administering to said patient an effective amount of a compound or a pharmaceutically acceptable salt thereof of any one of embodiments 1 to 119, or a pharmaceutical composition of embodiment 120. [0631] Embodiment 155. A method of inhibiting cell proliferation, in vitro or in vivo, said method comprising contacting a cell with an effective amount of a compound or a pharmaceutically acceptable salt thereof of any one of embodiments 1 to 119, or a pharmaceutical composition of embodiment 120.

[0632] Embodiment 156. A method for inhibiting PRMT5 activity in a cell, comprising contacting the cell in which inhibition of PRMT5 activity is desired with an effective amount of a compound or pharmaceutically acceptable salt thereof of any one of embodiments 1 to 119, or a pharmaceutical composition of embodiment 120.

[0633] Embodiment IB. A compound of Formula (I): or a pharmaceutically acceptable salt thereof, wherein

X¹ is C(R^laR^lb), O, or NR¹;

X² is C(R^2aR^2b), O, or NR²;

X³ is C(R^3aR^3b), O, or NR³;

X⁴ is C(R^4aR^4b), O, NR⁴, S, S(O), or S(O)₂;

X⁵ is C(R^5aR^5b), O, NR⁵, S, S(O), or S(O)₂;

X⁶ is C(R^6aR^6b), O, NR⁶, S, S(O), or S(O)₂;

R¹, R², and R³ are each independently H or Ci-4 alkyl;

R^4a,R^4b, R^5a _jR^5b _; R^6a _; and R^6b are each independently H, C1-4 alkyl, C1-4 haloalkyl, CM hydroxyalkyl, or C1-4 haloalkyl(OH); ring A is heterocycloalkyl having 4 to 7 ring members with at least 1 nitrogen atom ring vertex, and 0 to 2 additional heteroatoms as ring vertices, wherein each additional heteroatom is independently N, O, S, S(O), or S(O)₂; ring B is Ce-io aryl or heteroaryl having 5 to 10 ring members with 1 to 4 heteroatom ring vertices, wherein each heteroatom is independently N, O, or S; p is 0, 1, 2, or 3; q is 0, 1, 2, or 3; each R⁷ is independently Ci-6 alkyl, Ci-6 haloalkyl, halo, Ci-6 alkoxy, Ci-6 haloalkoxy, -C(O)Ci-₆ alkyl, -C(O)Ci-₆ haloalkyl, -C(O)OCi-₆ alkyl, or -C(O)OCi-₆ haloalkyl; each R⁸ is independently Ci-6 alkyl, Ci-6 haloalkyl, halo, CN, Ci-6 alkoxy, Ci-6 haloalkoxy, C3- 6 cycloalkyl, -O-C3-6 cycloalkyl, -C(O)Ci-6 alkyl, -C(O)Ci-6 haloalkyl, -C(O)OCi-6 alkyl, -C(O)OCi-6 haloalkyl, or heterocycloalkyl having 4 to 6 ring members with 1 to 3 heteroatom ring vertices, wherein each heteroatom is independently N, O, or S, and wherein the heterocycloalkyl is substituted with 0, 1, or 2 R^8a; each R^8a is independently C1-4 alkyl, halo, or C1-4 haloalkyl; alternatively, one R⁷ attached to ring A and one R⁸ attached to ring B combine to form ring C, wherein ring C is C4-7 cycloalkyl or heterocycloalkyl having 4 to 7 ring members with 1 to 3 heteroatom ring vertices, wherein each heteroatom is independently N, O, S, S(O), or S(O)₂, wherein ring C is substituted with 0, 1, 2, or 3 R^7a, and ring A, ring B, and ring C form a fused tricyclic moiety; each R^7a is independently C1-4 alkyl, halo, or C1-4 haloalkyl; alternatively, two R^7a groups attached to the same carbon atom combine to form oxo; and R⁹ is H, C1-4 alkyl, halo, or Ci^ haloalkyl.

[0634] Embodiment 2B. The compound or a pharmaceutically acceptable salt thereof of embodiment IB, wherein one R⁷ attached to ring A and one R⁸ attached to ring B combine to form ring C, wherein ring C is C4-7 cycloalkyl or heterocycloalkyl having 4 to 7 ring members with 1 to 3 heteroatom ring vertices, wherein each heteroatom is independently N, O, S, S(O), or S(O)₂, wherein ring C is substituted with 0, 1, 2, or 3 R^7a, and ring A, ring B, and ring C form a fused tricyclic moiety.

[0635] Embodiment 3B. The compound or a pharmaceutically acceptable salt thereof of embodiment IB or 2B, wherein X¹ is C(R^laR^lb).

[0636] Embodiment 4B. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments IB to 3B, wherein X¹ is CH₂.

[0637] Embodiment 5B. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments IB to 4B, wherein X² is NR².

[0638] Embodiment 6B. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments IB to 5B, wherein X² is NH. [0639] Embodiment 7B. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments IB to 4B, wherein X² is O.

[0640] Embodiment 8B. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments IB to 4B, wherein X² is C(R^2aR^2b).

[0641] Embodiment 9B. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments IB to 4B and 8B, wherein X² is CH2.

[0642] Embodiment 10B. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments IB to 9B, wherein X³ is C(R^3aR^3b).

[0643] Embodiment 11B. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments IB to 10B, wherein X³ is CH2.

[0644] Embodiment 12B. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments IB to 11B, wherein X⁴ is C(R^4aR^4b), O, or NR⁴.

[0645] Embodiment 13B. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments IB to 12B, wherein X⁴ is C(R^4aR^4b).

[0646] Embodiment 14B. The compound or a pharmaceutically acceptable salt thereof of embodiment 13B, wherein R^4a and R^4b are each H.

[0647] Embodiment 15B. The compound or a pharmaceutically acceptable salt thereof of embodiment 13B, wherein R^4a is methyl, and R^4b is H.

[0648] Embodiment 16B. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments IB to 15B, wherein X⁵ is C(R^5aR^5b), O, or NR⁵.

[0649] Embodiment 17B. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments IB to 16B, wherein X⁵ is O.

[0650] Embodiment 18B. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments IB to 17B, wherein X⁶ is C(R^6aR^6b), O, or NR⁶.

[0651] Embodiment 19B. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments IB to 18B, wherein X⁶ is C(R^6aR^6b).

[0652] Embodiment 20B. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments IB to 19B, wherein R^6a and R^6b are each H. [0653] Embodiment 21B. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments IB to 18B, wherein R^6a is methyl; and R^6b is H.

[0654] Embodiment 22B. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments IB to 21B, wherein ring A is heterocycloalkyl having 5 to 6 ring members with at least 1 nitrogen atom and 0 to 1 additional heteroatom as ring vertices, wherein each additional heteroatom is N, O, or S.

[0655] Embodiment 23B. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments IB to 21B, wherein ring A is pyrrolidinyl, piperidinyl, piperazinyl, or morpholinyl.

[0656] Embodiment 24B. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments IB to 21B, wherein ring A is piperidinyl, piperazinyl, or morpholinyl.

[0657] Embodiment 25B. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments IB to 21B, wherein ring A is piperidinyl, substituted with 0, 1, or 2 R⁷.

[0658] Embodiment 26B. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments IB to 21B, wherein ring A is piperazinyl, substituted with 0, 1, or 2 R⁷.

[0659] Embodiment 27B. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments IB to 21B, wherein ring A is morpholinyl, substituted with 0, 1, or 2 R⁷.

[0660] Embodiment 28B. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments IB to 27B, wherein each R⁷ is independently Ci-6 alkyl, Ci-6 haloalkyl, halo, Ci-6 alkoxy, or Ci-6 haloalkoxy.

[0661] Embodiment 29B. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments IB to 27B, wherein each R⁷ is independently CH alkyl, halo, or Ci-4 alkoxy.

[0662] Embodiment 30B. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments IB to 27B, wherein each R⁷ is independently methyl, fluoro, or methoxy. [0663] Embodiment 31B. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments IB to 27B, wherein each R⁷ is independently methyl or fluoro.

[0664] Embodiment 32B. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments IB to 31B, having Formula (la): wherein: ring B is phenyl or heteroaryl having 5 to 6 ring members with 1 to 3 heteroatom ring vertices, wherein each heteroatom is independently N, O, or S; p is 0, 1, or 2; q is 0, 1, or 2; and ring C is fused to (a) two adjacent ring vertices of ring A and (b) two adjacent ring vertices of ring B, and ring C is C4-7 cycloalkyl or heterocycloalkyl having 4 to 7 ring members with 1 to 3 heteroatom ring vertices, wherein each heteroatom is independently N, O, S, S(O), or S(O)₂.

[0665] Embodiment 33B. The compound or a pharmaceutically acceptable salt thereof of embodiment 32B, wherein:

X¹ is C(R^laR^lb);

X² is C(R^2aR^2b), O, or NR²;

X³ is C(R^3aR^3b);

X⁴ is C(R^4aR^4b);

X^s is O;

X⁶ is C(R^6aR^6b);

R² is H or C1-4 alkyl;

R^la, R^lb, R^2a, R^2b, R^3a, and R^3b are each independently H or C1-4 alkyl;

R^4a, R^4b, R^6a, and R^6b are each independently H or C1-4 alkyl; ring A is heterocycloalkyl having 5 to 7 ring members with at least 1 nitrogen atom and 0 to 1 additional heteroatom as ring vertices, wherein each additional heteroatom is N or O; ring B is phenyl or heteroaryl having 5 to 6 ring members with 1 to 3 heteroatom ring vertices, wherein each heteroatom is independently N, O, or S; ring C is C5-7 cycloalkyl or heterocycloalkyl having 5 to 7 ring members with 1 to 3 heteroatom ring vertices, wherein each heteroatom is independently N, O, or S, wherein ring C is substituted with 0, 1, or 2 R^7a, p is 0 or 1; q is 1;

R⁷ is C1-4 alkyl, halo, or C1-4 alkoxy,;

R⁸ is C1-4 alkyl, C1-4 haloalkyl, halo, CN, C1-4 alkoxy, C1-4 haloalkoxy, or C3-6 cycloalkyl; each R^7a is independently C1-4 alkyl or halo; and

R⁹ is H.

[0666] Embodiment 34B. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments IB to 31B, having Formula (Ial-1): wherein:

X^a is O, NH, CH₂, or CHR⁷; p is 0 or 1; q is 0, 1, or 2; and ring C is C4-7 cycloalkyl or heterocycloalkyl having 4 to 7 ring members with 1 to 3 heteroatom ring vertices, wherein each heteroatom is independently N, O, S, S(O), or S(O)2.

[0667] Embodiment 35B. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments IB to 31B, having Formula (Ial-2): wherein,

X^a is O, NH, CH₂, or CHR⁷; p is 0 or 1; q is 0, 1, or 2; and ring C is C4-7 cycloalkyl or heterocycloalkyl having 4 to 7 ring members with 1 to 3 heteroatom ring vertices, wherein each heteroatom is independently N, O, S, S(O), or S(O)₂.

[0668] Embodiment 36B. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments IB to 35B, wherein ring C is C5-6 cycloalkyl substituted with 0, 1, or 2 R^7a.

[0669] Embodiment 37B. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments IB to 36B, wherein ring C is Ce cycloalkyl substituted with 0, 1, or 2 R^7a.

[0670] Embodiment 38B. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments IB to 36B, wherein ring C is C5 cycloalkyl substituted with 0, 1, or 2 R^7a.

[0671] Embodiment 39B. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments IB to 35B, wherein ring C is heterocycloalkyl having 5 to 6 ring members with 1 to 2 heteroatom ring vertices, wherein each heteroatom is independently N, O, or S, wherein ring C is substituted with 0, 1, or 2 R^7a.

[0672] Embodiment 40B. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments IB to 35B and 39B, wherein ring C is heterocycloalkyl having 5 ring members with 1 to 2 heteroatom ring vertices, wherein each heteroatom is independently N, O, or S, wherein ring C is substituted with 0, 1, or 2 R^7a. [0673] Embodiment 41B. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments IB to 35B and 39B, wherein ring C is heterocycloalkyl having 6 ring members with 1 to 2 heteroatom ring vertices, wherein each heteroatom is independently N, O, or S, wherein ring C is substituted with 0, 1, or 2 R^7a.

[0674] Embodiment 42B. The compound or a pharmaceutically acceptable salt thereof of embodiment 40B, wherein ring C is tetrahydrofuranyl substituted with 0 R^7a.

[0675] Embodiment 43B. The compound or a pharmaceutically acceptable salt thereof of embodiment 41B, wherein ring C is tetrahydropyranyl substituted with 0 or 1 R^7a.

[0676] Embodiment 44B. The compound or a pharmaceutically acceptable salt thereof of embodiment 41B, wherein ring C is tetrahydropyranyl substituted with 0 R^7a.

[0677] Embodiment 45B. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments IB to 31B, having Formula (Ia2-1): wherein,

X^a is O, NH, CH₂, or CHR⁷;

X^7a is absent, O, CH₂, or CHR^7a;

X^7b is absent, O, CH₂, or CHR^7a; p is 0, 1, or 2; and q is 0, 1, or 2, provided that X^7a and X^7b are not each absent or O.

[0678] Embodiment 46B. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments IB to 31B, having Formula (Ia2-2):

wherein,

X^a is O, NH, CH₂, or CHR⁷;

X^7a is absent, O, CH₂, or CHR^7a;

[0679] Embodiment 47B. The compound or a pharmaceutically acceptable salt thereof of embodiment 45B or 46B, wherein

X^a is O, CH₂, or CHR⁷;

X^7a is O, CH₂, or CHR^7a; and

X^7b is O, CH₂, or CHR^7a.

[0680] Embodiment 48B. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments 45B to 47B, wherein X^7a is O; and X^7b is CH₂.

[0681] Embodiment 49B. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments 45B to 47B, wherein X^7a is CH₂; and X⁷¹⁵ is O.

[0682] Embodiment SOB. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments 45B to 47B, wherein X^7a is CH₂; and X⁷¹¹ is CH₂.

[0683] Embodiment SIB. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments 45B to 47B, wherein X^7a is O; and X^7b is CH(CHa).

[0684] Embodiment 52B. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments 45B to 47B, wherein X^7a is CH(CHs); and X^7b is O.

[068S] Embodiment 53B. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments 45B to 47B, wherein X^7a is CH₂ and X^ is CH(CH3); or X^7a is CH(CH₃) and X^7b is CH₂. [0686] Embodiment 54B. The compound or a pharmaceutically acceptable salt thereof of embodiment 45B or 46B, wherein X^7a is absent; and X^7b is CH2.

[0687] Embodiment 55B. The compound or a pharmaceutically acceptable salt thereof of embodiment 45B or 46B, wherein X^7a is absent; and X^7b is O.

[0688] Embodiment 56B. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments IB to 55B, wherein each R⁸ is independently C1-6 alkyl, C1-6 haloalkyl, halo, CN, C1-6 alkoxy, C1-6 haloalkoxy, or C3-6 cycloalkyl.

[0689] Embodiment 57B. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments IB to 56B, wherein q is 1; and R⁸ is C1-6 alkyl, Ci-6 haloalkyl, halo, CN, C1-6 alkoxy, C1-6 haloalkoxy, or C3-6 cycloalkyl.

[0690] Embodiment 58B. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments IB to 57B, wherein q is 1; and R⁸ is chloro, CN, isopropyl, cyclopropyl, fluoromethyl, difluoromethyl, trifluoromethyl, fluoromethyl-O-, difluoromethyl-O-, or trifluoromethyl-O-.

[0691] Embodiment 59B. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments IB to 58B, wherein q is 1; and R⁸ is chloro, trifluoromethyl, or difluoromethyl-O-.

[0692] Embodiment 60B. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments IB to 59B, wherein q is 1; and R⁸ is chloro.

[0693] Embodiment 61B. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments IB to 59B, wherein q is 1; and R⁸ is trifluoromethyl.

[0694] Embodiment 62B. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments IB to 59B, wherein q is 1; and R⁸ is difluoromethyl-O-.

[0695] Embodiment 63B. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments IB to 31B, wherein the moiety has the formula: wherein:

X^a is O, NH, CH₂, or CHR⁷;

X^7a is O, CH₂, or CHR^7a;

X^7b is O, CH₂, or CHR^7a; each R^7a is independently C1-4 alkyl; each R⁷ is independently F, C1.4 alkyl, or C1.4 alkoxy; and

[0696] Embodiment 64B. The compound or a pharmaceutically acceptable salt thereof of embodiment 63B, wherein X^a is O, NH, CH₂, CHF, C(CH₃), or C(OCH₃); X^7a is O, CH₂, or CH(CH₃); X^7b is O or CH₂; R⁷ is F, CH₃, or OCH₃; R⁸ is chloro, CN, isopropyl, cyclopropyl, difluoromethyl, trifluoromethyl, difluoromethyl-O-, or trifluoromethyl-O-, provided that X^7a and X⁷⁸ are not each O.

[0697] Embodiment 65B. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments IB to 64B, wherein R⁹ is H. [0698] Embodiment 66B. The compound or a pharmaceutically acceptable salt thereof of any one of embodiments IB to 65B, wherein: wherein X2 is O, NH, or CH2; and R^4a is H or C1-4 alkyl.

[0699] Embodiment 67B. The compound or a pharmaceutically acceptable salt thereof of embodiment 66B, wherein X2 is O; and R^4a is H.

[0700] Embodiment 68B. The compound or a pharmaceutically acceptable salt thereof of embodiment 66B, wherein X2 is O; and R^4a is methyl.

[0701] Embodiment 69B. The compound or a pharmaceutically acceptable salt thereof of embodiment 66B, wherein X2 is NH; and R^4a is H.

[0702] Embodiment 70B. The compound or a pharmaceutically acceptable salt thereof of embodiment 66B, wherein X2 is NH; and R^4a is methyl.

[0703] Embodiment 71B. The compound or a pharmaceutically acceptable salt thereof of embodiment 66B, wherein X2 is CH2; and R^4a is H.

[0704] Embodiment 72B. The compound or a pharmaceutically acceptable salt thereof of embodiment 66B, wherein X2 is CH2; and R^4a is methyl.

[0705] Embodiment 73B. The compound or a pharmaceutically acceptable salt thereof of embodiment IB, represented by any one of the structures of Examples 1 to 3 and 5 to 42 in Table 1.

[0706] Embodiment 74B. A compound or a pharmaceutically acceptable salt thereof, represented by any one of the structures of Examples 1 to 44.

[0707] Embodiment 75B. A pharmaceutical composition comprising a compound or a pharmaceutically acceptable salt thereof of any one of embodiments IB to 74B, and a pharmaceutically acceptable excipient.

[0708] Embodiment 76B. A method for treating a disease treatable by inhibition of protein arginine N-methyltransferase 5 (PRMT5) in a patient comprising administering to the patient a therapeutically effective amount of a compound or a pharmaceutically acceptable salt thereof of any one of embodiments IB to 74B, or a pharmaceutical composition of embodiment 75.

[0709] Embodiment 77B. The method of embodiment 76B, wherein the disease is cancer.

[0710] Embodiment 78B. A method of treating an MTAP null cancer in a patient comprising administering to the patient a therapeutically effective amount of a compound or a pharmaceutically acceptable salt thereof of any one of embodiments IB to 74B, or a pharmaceutical composition of embodiment 75B.

[0711] Embodiment 79B. A method for treating cancer in a patient, wherein the cancer is characterized by a reduction or absence of MTAP gene expression, an absence of the MTAP gene, an absence of MTAP protein, a reduced level of MTAP protein, a reduced function of MTAP protein, or a combination thereof, comprising administering to the patient a therapeutically effective amount of a compound or pharmaceutically acceptable salt thereof of any one of embodiments IB to 74B, or a pharmaceutical composition of embodiment 75B.

[0712] Embodiment 80B. A method of treating cancer in a patient comprising administering to the patient a therapeutically effective amount of a compound or a pharmaceutically acceptable salt thereof of any one of embodiments IB to 74B, or a pharmaceutical composition of embodiment 75B.

[0713] Embodiment 81B. The method of any one of embodiments 77B to 80B, wherein the cancer is a MTA-accumulating cancer.

[0714] Embodiment 82B. The method of embodiment 77B or 81B, wherein the cancer is deficient in CDKN2A.

[0715] Embodiment 83B. The method of any one of embodiments 77B to 82B, wherein the cancer is a solid tumor.

[0716] Embodiment 84B. The method of embodiment 83B, wherein the solid tumor is malignant.

[0717] Embodiment 85B. The method of any one of embodiments 76B to 84B, wherein the patient is in recognized need of such treatment.

[0718] Embodiment 86B. The method of any one of embodiments 77B to 85B, wherein the cancer is biliary tract cancer, glioblastoma, ovarian cancer, malignant peripheral nerve sheath tumors (MPNST), colon cancer, esophageal cancer ( e.g., esophageal squamous cell carcinoma or esophageal adenocarcinoma), gastric cancer, bladder cancer (e.g., bladder urothelial carcinoma, gallbladder cancer), pancreatic cancer (e.g., pancreatic adenocarcinoma), mesothelioma, melanoma, lung cancer e.g., non-small cell lung cancer (NSCLC); e.g., lung squamous or lung adenocarcinoma)), astrocytoma, undifferentiated pleiomorphic sarcoma, lymphoma (e.g., diffuse large B-cell lymphoma (DLBCL)), leukemia, head and neck cancer (e.g., head and neck squamous cell carcinoma), stomach adenocarcinoma, myxofibrosarcoma, cholangiosarcoma, cancer of the brain, stomach, kidney, breast, endometrium, urinary tract, Ever, soft tissue, pleura and large intestine, or sarcoma.

[0719] Embodiment 87B. The method of any one of embodiments 77B to 85B, wherein the cancer is selected from the group consisting of leukemia, esophageal cancer, glioma, melanoma, pancreatic, non-small cell lung cancer, bladder cancer, astrocytoma, osteosarcoma, head and neck cancer, myxoid chondrosarcoma, ovarian cancer, endometrial cancer, breast cancer, soft tissue sarcoma, non-Hodgkin lymphoma, and mesothelioma.

[0720] Embodiment 88B. The method of any one of embodiments 77B to 85B, wherein the cancer is selected from the group consisting of non-small cell lung cancer (squamous and adenocarcinoma), urothelial cancer (bladder and upper urinary tract), esophageal cancer, and gastric cancer.

[0721] Embodiment 89B. A compound or a pharmaceutically acceptable salt thereof of any one of embodiments IB to 74B, or a pharmaceutical composition of embodiment 75B, for use in therapy.

[0722] Embodiment 90B. A compound or a pharmaceutically acceptable salt thereof of any one of embodiments IB to 74B, or a pharmaceutical composition of embodiment 75B, for use in the treatment of cancer.

[0723] Embodiment 91B. The compound or the pharmaceutically acceptable salt thereof, or the pharmaceutical composition, for use according to embodiment 90B, wherein said cancer is an MTAP null cancer.

[0724] Embodiment 92B. The compound or the pharmaceutically acceptable salt thereof, or the pharmaceutical composition, for use according to embodiment 90B, wherein said cancer is characterized by a reduction or absence of MTAP gene expression, an absence of the MTAP gene, an absence of MTAP protein, a reduced level of MTAP protein, or a reduced function of MTAP protein, or a combination thereof.

[0725] Embodiment 93B. The compound or the pharmaceutically acceptable salt thereof, or the pharmaceutical composition, for use according to any one of embodiments 90B to 92B, wherein said cancer is MTA-accumulating cancer.

[0726] Embodiment 94B. The compound or the pharmaceutically acceptable salt thereof, or the pharmaceutical composition, for use according to any one of embodiments 90B to 93B, wherein said cancer is deficient in CDKN2A.

[0727] Embodiment 95B. The compound or the pharmaceutically acceptable salt thereof, or the pharmaceutical composition, for use according to any one of embodiments 90B to 94B, wherein said cancer is a solid tumor.

[0728] Embodiment 96B. The compound or the pharmaceutically acceptable salt thereof, or the pharmaceutical composition, for use according to embodiment 95B, wherein the solid tumor is malignant.

[0729] Embodiment 97B. The compound or the pharmaceutically acceptable salt thereof, or the pharmaceutical composition, for use according to any one of embodiments 90B to 96B, wherein said cancer is biliary tract cancer, glioblastoma, ovarian cancer, malignant peripheral nerve sheath tumors (MPNST), colon cancer, esophageal cancer (e.g., esophageal squamous cell carcinoma or esophageal adenocarcinoma), gastric cancer, bladder cancer (e.g., bladder urothelial carcinoma, gallbladder cancer), pancreatic cancer ( e.g., pancreatic adenocarcinoma), mesothelioma, melanoma, lung cancer (e.g., non-small cell lung cancer (NSCLC; e.g., lung squamous or lung adenocarcinoma)), astrocytoma, undifferentiated pleiomorphic sarcoma, lymphoma (e.g., diffuse large B-cell lymphoma (DLBCL)), leukemia, head and neck cancer (e.g., head and neck squamous cell carcinoma), stomach adenocarcinoma, myxofibrosarcoma, cholangiosarcoma, cancer of the brain, stomach, kidney, breast, endometrium, urinary tract, fiver, soft tissue, pleura and large intestine or sarcoma.

[0730] Embodiment 98B. The compound or the pharmaceutically acceptable salt thereof, or the pharmaceutical composition for use according to any one of embodiments 90B to 96B, wherein said cancer is leukemia, esophageal cancer, glioma, melanoma, pancreatic, non- small cell lung cancer, bladder cancer, astrocytoma, osteosarcoma, head and neck cancer, myxoid chondrosarcoma, ovarian cancer, endometrial cancer, breast cancer, soft tissue sarcoma, non-Hodgkin lymphoma or mesothelioma.

[0731] Embodiment 99B. Use of a compound or a pharmaceutically acceptable salt thereof of any one of embodiments IB to 74B, or a pharmaceutical composition of embodiment 75B, in the manufacture of a medicament for use therapy.

[0732] Embodiment 100B. Use of a compound or a pharmaceutically acceptable salt thereof of any one of embodiments IB to 74B, or a pharmaceutical composition of embodiment 75B, in the manufacture of a medicament for the treatment of cancer.

[0733] Embodiment 101B. The use of embodiment 100B, wherein said cancer is an MTAP null cancer.

[0734] Embodiment 102B. The use of embodiment 100B, wherein said cancer is characterized by a reduction or absence of MTAP gene expression, an absence of the MTAP gene, an absence of MTAP protein, a reduced level of MTAP protein, a reduced function of MTAP protein, or a combination thereof.

[0735] Embodiment 103B. The use of any one embodiments 100B to 102B, wherein said cancer is MTA-accumulating cancer,.

[0736] Embodiment 104. The use of any one of embodiments 100B to 103B, wherein said cancer is deficient in CDKN2A.

[0737] Embodiment 105B. The use of any one of embodiments 100B to 102B, wherein said cancer is a solid tumor.

[0738] Embodiment 106B. The use of embodiment 105B, wherein said solid tumor is malignant.

[0739] Embodiment 107B. The use of any one of embodiments 100B to 106B, wherein said cancer is biliary tract cancer, glioblastoma, ovarian cancer, malignant peripheral nerve sheath tumors (MPNST), colon cancer, esophageal cancer (e.g., esophageal squamous cell carcinoma or esophageal adenocarcinoma), gastric cancer, bladder cancer (e.g., bladder urothelial carcinoma, gallbladder cancer), pancreatic cancer ( e.g., pancreatic adenocarcinoma), mesothelioma, melanoma, lung cancer (e.g., non-small cell lung cancer (NSCLC); e.g., lung squamous or lung adenocarcinoma)), astrocytoma, undifferentiated pleiomorphic sarcoma, lymphoma (e.g., diffuse large B-cell lymphoma (DLBCL)), leukemia, head and neck cancer (e.g., head and neck squamous cell carcinoma), stomach adenocarcinoma, myxofibrosarcoma, cholangiosarcoma, cancer of the brain, stomach, kidney, breast, endometrium, urinary tract, liver, soft tissue, pleura and large intestine or sarcoma.

[0740] Embodiment 108B. The use of any one of embodiments 100B to 106B, wherein said cancer is leukemia, esophageal cancer, glioma, melanoma, pancreatic, non-small cell lung cancer, bladder cancer, astrocytoma, osteosarcoma, head and neck cancer, myxoid chondrosarcoma, ovarian cancer, endometrial cancer, breast cancer, soft tissue sarcoma, nonHodgkin lymphoma or mesothelioma.

[0741] Embodiment 109B. A method of inhibiting protein arginine N-methyltransferase 5 (PRMT5) in vivo in a patient, said method comprising administering to said patient an effective amount of a compound or a pharmaceutically acceptable salt thereof of any one of embodiments IB to 74B, or a pharmaceutical composition of embodiment 75B.

[0742] Embodiment HOB. A method of inhibiting cell proliferation, in vitro or in vivo, said method comprising contacting a cell with an effective amount of a compound or a pharmaceutically acceptable salt thereof of any one of embodiments IB to 74B, or a pharmaceutical composition of embodiment 75B.

[0743] Embodiment 111B. A method for inhibiting PRMT5 activity in a cell, comprising contacting the cell in which inhibition of PRMT5 activity is desired with an effective amount of a compound or pharmaceutically acceptable salt thereof of any one of embodiments IB to 74B, or a pharmaceutical composition of embodiment75B.

EXAMPLES

[0744] The following examples are put forth so as to provide those of ordinary skill in the art with a complete disclosure and description of how to make and use the present invention, and are not intended to limit the scope of what the inventors regard as their invention, nor are they intended to represent that the experiments below were performed or that they are all of the experiments that may be performed. It is to be understood that exemplary descriptions written in the present tense were not necessarily performed, but rather that the descriptions can be performed to generate data and the like of a nature described therein. Efforts have been made to ensure accuracy with respect to numbers used (e.g., amounts, temperature, etc.), but some experimental errors and deviations should be accounted for. List of Selected Abbreviations:

MeOH - methanol

MeCN - acetonitrile

PdCh(dppf)-DCM adduct - palladium chloride- 1,1 -ferrocenediyl-bis(diphenylphosphino)- dichloromethane adduct

K2CO3 - potassium carbonate

APhos Pd G3 - palladium G3-(4-(A, A-Dimethylamino)phenyl)di-terr-butylphosphine, [4- (Di-terZ-butylphosphino)-7V,A-dimethylaniline-2-(2'-aminobiphenyl)]palladium(II) methanesulfonate dppf Pd G3 - methanesulfonato l,l-ferrocenediyl-bis(diphenylphosphino) (2'-amino-l,l'- biphenyl-2-yl) palladium(II)

DI H2O - deionized water

(4,4'-dtbbpy)NiC12 - [4,4'-Bis(l,l-dimethylethyl)-2,2'-bipyridine] nickel (II) dichloride

[Ir(dtbbpy)(ppy)2]PFe - [4,4'-Bi5(l,l-dimethylethyl)-2,2'-bipyridine-Al,Al']bis[2-(2- pyridinyl-7V)phenyl-C]iridium(III) hexafluorophosphate

Aminosupersilane - 7V-( Adamantan- 1 -yl)- 1,1,1 ,3,3,3-hexamethyl-2-(trimethylsilyl)trisilan-2- amine

DPPF Pd G3 - Methanesulfonato l,l-ferrocenediyl-bis(diphenylphosphino) (2'-amino-l,l'- biphenyl-2-yl) palladium(II)

Na2COs - sodium carbonate

AcCN - acetonitrile

TsOH - p-Toluenesulfonic acid i-PrOH - isopropanol

THF - tetrahydrofuran

DMF - 7V,7V-dimethylformanride

DCM -dichloromethane

TFA - trifluoroacetic acid

NaH - sodium hydride

TIPSOTf - Triisopropylsilyl trifluoromethanesulfonate

NH4CI - ammonium chloride

EtOAC - ethyl acetate DBU - l,8-diazabicyclo(5.4.0)undec-7-ene

Synthesis Examples Carboxylic Acid (CA) intermediate synthesis

Intermediate CAI: 1:1 mixture of (R)-4-amino-l,3,6,7,8,9-hexahydrofuro[3,4-c]quinoline- 8-carboxylic acid and (S)-4-amino-l,3,6,7,8,9-hexahydrofuro[3,4-c]quinoline-8-carboxylic acid

CA1

Step 1: 4-cyano-2,5-dihydrofuran-3-yl trifluoromethanesulfonate

[0745] To a stirred solution of 4-oxooxolane-3-carbonitrile (9.0 g, 81.00 mmol) and DIEA (16.93 mL, 97.21 mmol) in DCM (180 mL) was added triflic anhydride (13.68 mL, 4.50 mmol) dropwise at -78 °C under nitrogen atmosphere. The resulting mixture was stirred at room temperature for 40 min. The reaction mixture was quenched by water and extracted with DCM. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under reduced pressure to afford 4-cyano-2,5- dihydrofuran-3-yl trifluoromethanesulfonate (14.25 g, crude) as a brown oil. 'H NMR (400 MHz, DMSO-J₆) 8 4.87 (s, 4H).

Step 2: Methyl 4-amino-l,3-dihydrofuro[3,4-c]quinoline-8-carboxylate

[0746] To a solution of 4-cyano-2,5-dihydrofuran-3-yl trifluoromethanesulfonate (14.25 g, 58.60 mmol) and methyl 4-amino-3-(4,4,5,5-tetramethyl-l,3,2-dioxaborolan-2-yl)benzoate (12.99 g, 46.88 mmol) in dioxane (280 mL) and H2O (28 mL) were added K2CO3 (24.30 g, 175.81 mmol) and Pd(dppf)Ch-CH2C12 (4.77 g, 5.86 mmol) at room temperature under nitrogen atmosphere. The resulting mixture was stirred at 80 °C for 16 h under nitrogen atmosphere. The resulting mixture was concentrated under reduced pressure. The residue was diluted with EtOAc (50 mL) and H2O (50 mL) and stirred at room temperature for 30 min. The precipitated solids were collected by filtration and washed with ethyl acetate (50 mL) and 2% MeOH in DCM (50 mL) to afford methyl 4-amino-lH,3H-furo[3,4-c]quinoline-8- carboxylate (8.11 g, 54%) as a brown solid. MS ESI calculated for C13H12N2O3 [M+H]⁺, 245.08; found, 244.95. 'H NMR (300 MHz, DMSO-d₆) 5 9.17 (s, 2H), 8.33 - 8.25 (m, 2H), 7.84 (d, J = 8.7 Hz, 1H), 5.52 (t, J = 3.6 Hz, 2H), 5.11 (t, J = 3.6 Hz, 2H), 3.91 (s, 3H).

Step 3: 1 :1 mixture of methyl (R)-4-amino-l,3,6,7,8,9-hexahydrofuro[3,4-c]quinoline-8- carboxylate and methyl (S)-4-amino-l,3,6,7,8,9-hexahydrofuro[3,4-c]quinoline-8- carboxylate

[0747] To a solution of methyl 4-amino-lH,3H-furo[3,4-c]quinoline-8-carboxylate (8.11 g, 33.20 mmol) and TEA (20.16 g, 199.22 mmol) in DMF (80 mL) was added AC2O (13.56 g, 132.81 mmol) at room temperature. The resulting solution was stirred at 90 °C for 5 h. The reaction mixture was diluted by water and EtOAc. The precipitated solids were collected by filtration and washed with EtOAc. The filtrate was extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under vacuum. The precipitated solids were dissolved in TFA (100 mL), then PtO2 (4.28 g, 18.86 mmol) was added to the above mixture. The resulting solution was stirred at room temperature for 16 h under hydrogen atmosphere. The reaction mixture was concentrated under vacuum. The residue was basified with NaHCOs (aq.) to pH 8 and extracted with DCM. The combined organic layers were filtered, the filter cake was washed with DCM/MeOH (1:1, v/v). The filtrate was collected and washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under vacuum. The residue was purified by flash column chromatography with 0 ~ 80% EtOAc in petroleum ether and further purified by reverse phase flash column chromatography with 5 ~ 20% MeCN in water (0.1% TFA) to afford 1:1 mixture of methyl (R)-4-amino- 1,3, 6,7,8, 9-hexahydrofuro[3,4-c]quinoline-8- carboxylate and methyl (S)-4-amino- 1,3, 6,7,8, 9-hexahydrofuro[3,4-c]quinoline-8- carboxylate (3.78 g, 39%) as a white solid. MS ESI calculated for C15H18N2O4 [M+H]⁺, 291.13; found, 291.20. 'H NMR (400 MHz, DMSO-d₆) 6 10.33 (s, 1H), 5.03 - 4.92 (m, 2H), 4.90 - 4.84 (m, 2H), 3.66 (s, 3H), 2.92 - 2.66 (m, 5H), 2.24 - 2.13 (m, 1H), 2.02 (s, 3H), 1.93 - 1.78 (m, 1H). Step 4: 1:1 mixture of (R)-4-amino-l,3,6,7,8,9-hexahydrofuro[3,4-c]quinoline-8-carboxylic acid and (S)-4-amino-l,3,6,7,8,9-hexahydrofuro[3,4-c]quinoline-8-carboxylic acid

CA1

[0748] To a 1:1 mixture of methyl (R)-4-amino- 1,3, 6,7,8, 9-hexahydrofuro[3,4-c]quinoline- 8-carboxylate and methyl (S)-4-amino- 1,3, 6,7,8, 9-hexahydrofuro[3,4-c]quinoline-8- carboxylate (1.8 g, 6.20 mmol) in dioxane (10 mL) and H2O (10 mL) was added NaOH (496 mg, 12.40 mmol) at room temperature. The resulting mixture was stirred at 80 °C for 16 h. The organic solvent was concentrated under vacuum. Then the mixture was acidified with HC1 (aq. IN) to pH 5. The precipitated solids were collected by filtration and washed with water, then dried under vacuum to afford 1:1 mixture of (R)-4-amino-l,3,6,7,8,9- hexahydrofuro[3,4-c]quinoline-8-carboxylic acid and (S)-4-amino-l,3,6,7,8,9- hexahydrofuro[3,4-c]quinoline-8-carboxylic acid (1.4 g, 77%) as a white solid. MS ESI calculated for C12H14N2O3 [M+H]⁺, 235.10; found, 235.05. 'H NMR (400 MHz, DMSO- ₆) 8 13.77 (s, 1H), 7.83 (s, 2H), 5.15 - 5.01 (m, 2H), 4.98 - 4.92 (m, 2H), 2.91 - 2.77 (m, 2H), 2.76 - 2.53 (m, 3H), 2.20 - 2.11 (m, 1H), 1.84 - 1.72 (m, 1H).

Intermediate CAI isomer 1: (S)-4-amino-l,3,6,7,8,9-hexahydrofuro[3,4-c]quinoline-8- carboxylic acid isomer 1

Isomer 1

Intermediate CAI isomer 2: (R)-4-amino- 1,3, 6,7,8, 9-hexahydrofuro[3, 4-c]quinolinc-8- carboxylic acid isomer 2

[0749] 1 :1 mixture of methyl (S)-4-acetamido-l,3,6,7,8,9-hexahydrofuro[3,4-c]quinoline- 8-carboxylate and methyl (R)-4-acetamido- 1,3, 6,7,8, 9-hexahydrofuro[3,4-c]quinoline-8- carboxylate (25.0 g, 80% purity) was separated by Prep-chiral HPLC with the following conditions: [Column: CHIRAL ART Cellulose-SC, 7*25 cm, 10 pm; Mobile Phase A: Hex (0.1% DEA)-HPLC, Mobile Phase B: EtOH: DCM=1: 1-HPLC; Flow rate: 200 mL/min; Gradient: 40% B to 40% B in 20 min; Wave Length: 220 nm; RTl(min): 13.84; RT2(min): 18.96; Sample Solvent: MeOH: DCM=1: 1— HPLC] to afford methyl (S)-4-acetamido- l,3,6,7,8,9-hexahydrofuro[3,4-c]quinoline-8-carboxylate (10.4 g) as a white solid with retention time at 13.84 minute. MS ESI calculated for C15H18N2O4 [M+H]⁺, 291.13; found, 291.10. 'H NMR (400 MHz, DMSO-d₆) 8 (ppm) 10.33 (s, 1H), 5.06 - 4.84 (m, 4H), 3.66 (s, 3H), 2.93 - 2.66 (m, 5H), 2.24 - 2.11 (m, 1H), 2.02 (s, 3H), 1.93 - 1.79 (m, 1H).

[0750] The chiral separation also afforded methyl (R)-4-acetamido-l,3,6,7,8,9- hexahydrofuro[3,4-c]quinoline-8-carboxylate (9.0 g) as a white solid with retention time at 18.96 minute. MS ESI calculated for C15H18N2O4 [M+H]⁺, 291.13; found, 291.10. 'H NMR (400 MHz, DMSO-d₆) 5 (ppm) 10.33 (s, 1H), 5.06 - 4.84 (m, 4H), 3.66 (s, 3H), 2.93 - 2.66 (m, 5H), 2.24 - 2.11 (m, 1H), 2.02 (s, 3H), 1.93 - 1.79 (m, 1H).

Isomer 1

[0751] A mixture of methyl (S)-4-acetamido-l,3,6,7,8,9-hexahydrofuro[3,4-c]quinoline-8- carboxylate (5.0 g, 17.22 mmol) and HC1 (cone.) (40 mL) was stirred at 100 °C for 2 h. The reaction mixture was concentrated under vacuum to afford (S)-4-amino-l,3,6,7,8,9- hexahydrofuro[3,4-c]quinoline-8-carboxylic acid hydrochloride isomer 1 (CAI isomer 1) (4.8 g, crude) as light yellow solid. MS ESI calculated for C12H14N2O3 [M+H]⁺, 235.10; found, 234.95. 'H NMR (400 MHz, DMSO- ₆) 8 (ppm) 14.13 (s, 1H), 12.52 (br, 1H), 7.79 (s, 2H), 5.14 - 5.00 (m, 2H), 4.98 - 4.95 (m, 2H), 2.94 - 2.78 (m, 2H), 2.77 - 2.64 (m, 2H), 2.63 - 2.53 (m, 1H), 2.19 - 2.10 (m, 1H), 1.85 - 1.71 (m, 1H).

Step-3:

[0752] A mixture of methyl (R)-4-acetamido-l,3,6,7,8,9-hexahydrofuro[3,4-c]quinofine-8- carboxylate (5.0 g, 17.22 mmol) and HC1 (cone.) (50 mL) was stirred at 100 °C for 2.5 h. The reaction mixture was concentrated under vacuum to afford (R)-4-amino-l,3,6,7,8,9- hexahydrofuro[3,4-c]quinoline-8-carboxylic acid hydrochloride isomer 2 (CAI isomer 2) (4.7 g, crude) as a light yellow solid. MS ESI calculated for C12H14N2O3 [M+H]⁺, 235.10; found, 235.00. 'H NMR (400 MHz, DMSO-d₆) 8 (ppm) 14.18 (s, 1H), 12.53 (brs, 1H), 7.81 (s, 2H), 5.14 - 5.00 (m, 2H), 4.99 - 4.94 (m, 2H), 2.88 - 2.78 (m, 2H), 2.76 - 2.64 (m, 2H), 2.63 - 2.54 (m, 1H), 2.22 - 2.09 (m, 1H), 1.84 - 1.72 (m, 1H). The absolute stereochemistry was confirmed by single crystal X-ray crystallography of Example 8, prepared using CAI isomer 2.

Intermediate CA2: 1:1 mixture of (R)-2-(tert-butylamino)-6,7,8,9-tetrahydro-5H- cyclohepta[b]pyridine-6-carboxylic acid and (S)-2-(tert-butylamino)-6,7,8,9-tetrahydro-5H- cyclohepta[b]pyridine-6-carboxylic acid

CA2

Step 1: 3-(bromomethyl)-2-chloropyridine

[0753] To a solution of 2-chloro-3-methylpyridine (25.00 g, 196.35 mmol) and N- bromosuccinimide (38.44 g, 215.99 mmol) in carbon tetrachloride (500 mL) was added Benzoyl peroxide (2.52 g, 9.82 mmol) at room temperature. The resulting solution was stirred at 80 °C for 3 h. The resulting mixture was concentrated under reduced pressure. The residue was purified by flash column chromatography with 0-25% ethyl acetate in petroleum ether to afford 3-(bromomethyl)-2-chloropyridine (21 g, 52%) as a light yellow solid. MS ESI calculated for C₆H₅BrClN [M+H]⁺, 205.93, 207.93; found, 205.85, 207.85. 'H NMR (400 MHz, DMSO-d₆) 6 8.39 (dd, J = 4.8, 2.0 Hz, 1H), 8.08 (dd, J = 7.6, 2.0 Hz, 1H), 7.49 - 7.44 (m, 1H), 4.74 (s, 2H).

Step 2: ethyl 2-((2-chloropyridin-3-yl)methyl)pent-4-enoate

[0754] To a solution of ethyl pent-4-enoate (26.12 g, 203.86 mmol) in tetrahydrofuran (300 mL) was added LDA (102.5 mL, 205.00 mmol, 2M in tetrahydrofuran) dropwise at -78 °C under nitrogen atmosphere. Then a solution of 3-(bromomethyl)-2-chloropyridine (21.0 g, 102.43 mmol) in tetrahydrofuran (120 mL) was added to the above mixture dropwise at - 78 °C under nitrogen atmosphere. The resulting mixture was stirred at room temperature for 5 h. The reaction mixture was quenched with saturated ammonium chloride aqueous solution at room temperature and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under vacuum. The residue was purified by flash column chromatography with 0 - 13% ethyl acetate in petroleinn ether to afford ethyl 2-[(2-chloropyridin-3-yl)methyl]pent-4-enoate (12.8 g, 49%) as a brown oil. MS ESI calculated for C13H16CINO2 [M+H]⁺, 254.09; found, 254.15. 'H NMR (400 MHz, DMSO-rfc) 8 8.29 (dd, J = 4.8, 2.0 Hz, 1H), 7.74 (dd, J = 7.6, 2.0 Hz, 1H), 7.40 - 7.35 (m, 1H), 5.83 - 5.72 (m, 1H), 5.14 - 5.01 (m, 2H), 3.97 (q, J = 7.2 Hz, 2H), 2.93 - 2.82 (m, 3H), 2.43 - 2.23 (m, 2H), 1.04 (t, J = 7.2 Hz, 3H Step 3: ethyl 2-((2-vinylpyridin-3-yl)methyl)pent-4-enoate

[0755] A mixture of ethyl 2-[(2-chloropyridin-3-yl)methyl]pent-4-enoate (12.8 g, 50.43 mmol), ethenyltrifluoro-A,-4-borane potassium (10.14 g, 75.67 mmol), (2- dicyclohexylphosphino-2',6'-diisopropoxy- 1 , 1 '-biphenyl)[2-(2'-amino- 1,1'- biphenyl)]palladium(II) methanesulfonate (4.22 g, 5.04 mmol) and sodium carbonate (16.04 g, 151.34 mmol) in dioxane (218 mL) and water (24 mL) was stirred at 100 °C for 16 h under nitrogen atmosphere. The reaction mixture was quenched by the addition of water and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under vacuum. The residue was purified by reverse phase flash column chromatography with 5 ~ 45% acetonitrile in water (0.1% formic acid) and further purified by flash column chromatography with 0 - 25% ethyl acetate in petroleum ether to afford ethyl 2-[(2-ethenylpyridin-3-yl)methyl]pent-4-enoate (8.00 g, 64%) as a yellow oil. MS ESI calculated for C15H19NO2 [M+H]⁺, 246.14; found, 246.20.

Step 4: ethyl 6,7-dihydro-5H-cyclohepta[b]pyridine-6-carboxylate

[0756] A mixture of ethyl 2-[(2-ethenylpyridin-3-yl)methyl]pent-4-enoate (8.00 g, 32.65 mmol) and [l,3-bis(2,4,6-trimethylphenyl)imidazolidin-2-ylidene]dichloro{ [2-(propan-2- yloxy)phenyl]methylidene} ruthenium (6.13 g, 9.79 mmol) in dichloromethane (200 mL) was stirred at 40 °C for 4 h under nitrogen atmosphere. The reaction mixture was concentrated under vacuum. The residue was purified by flash column chromatography with 0 - 50% ethyl acetate in petroleum ether to afford ethyl 5H,6H,7H-cyclohepta[b]pyridine-6-carboxylate (3.65 g, 51%) as a brown oil. MS ESI calculated for C13H15NO2 [M+H]⁺, 218.11; found, 218.05. 'H NMR (400 MHz, DMSO-d₆) 8 8.39 (d, J = 4.8 Hz, 1H), 7.59 (d, J = 7.6 Hz, 1H), 7.18 - 7.12 (m, 1H), 6.57 (d, 7= 12.8, 1H), 6.17 - 6.11 (m, 1H), 4.02 (q, J = 7.2 Hz, 2H), 3.10 - 2.88 (m, 3H), 2.64 - 2.58 (m, 2H), 1.12 (t, J = 7.2 Hz, 3H).

Step 5: ethyl 6,7,8,9-tetrahydro-5H-cyclohepta[b]pyridine-6-carboxylate

[0757] To a solution of ethyl 5H,6H,7H-cyclohepta[b]pyridine-6-carboxylate (3.00 g, 13.81 mmol) in ethanol (30 mL) was added Pd/C (294 mg, 10% active on carbon) at room temperature. The mixture was stirred at room temperature for 16 h under hydrogen atmosphere (1 atm.). The resulting mixture was filtered, the filter cake was washed with ethanol. The filtrate was collected and concentrated under reduced pressure to afford ethyl 5H,6H,7H,8H,9H-cyclohepta[b]pyridine-6-carboxylate (2.3 g, 72%) as a brown oil. MS ESI calculated for C13H17NO2 [M+H]⁺, 220.13; found, 220.05. 'H NMR (400 MHz, Chloroform- d) 8 8.34 (d, J = 4.8 Hz, 1H), 7.47 (d, J = 7.6, 1H), 7.10 - 7.06 (m, 1H), 4.20 - 4.12 (m, 2H), 3.17 - 2.96 (m, 4H), 2.57 - 2.46 (m, 1H), 2.25 - 2.20 (m, 1H), 2.10 - 1.93 (m, 2H), 1.67 - 1.53 (m, 1H), 1.27 (t, J = 7.2 Hz, 3H).

Step 6: 6-(ethoxycarbonyl)-6,7,8,9-tetrahydro-5H-cyclohepta[b]pyridine 1-oxide

[0758] To a stirred solution of ethyl 5H,6H,7H,8H,9H-cyclohepta[b]pyridine-6-carboxylate (2.30 g, 10.48 mmol) in dichloromethane (23 mL) was added 3-chloroperoxybenzoic acid (2.71 g, 15.73 mmol) at 0 °C under nitrogen atmosphere. The mixture was stirred at room temperature for 16 h. The reaction mixture was diluted with saturated sodium bicarbonate aqueous solution and extracted with dichloromethane. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under vacuum. The residue was purified by flash column chromatography with 0 ~ 5% methanol in dichloromethane to afford 6-(ethoxycarbonyl)-5H,6H,7H,8H,9H-cyclohepta[b]pyridin-l- ium- 1-olate (1.4 g, 56%) as a brown solid. MS ESI calculated for C13H17NO3 [M+H]⁺, 236.12; found, 236.10.

Step 7: ethyl 2-(tert-butylamino)-6,7,8,9-tetrahydro-5H-cyclohepta[b]pyridine-6-carboxylate

[0759] To a stirred solution of 6-(ethoxycarbonyl)-5H,6H,7H,8H,9H-cyclohepta[b]pyridin- 1-ium-l-olate (1.40 g, 5.95 mmol) and (4-methylbenzene)sulfonyl 4-methylbenzene-l- sulfonate (4.86 g, 14.88 mmol) in tetrahydrofuran (40 mL) was added 2-methylpropan-2- amine (1.96 g, 26.77 mmol) at room temperature. The resulting mixture was stirred at room temperature for 3 h. Then (4-methylbenzene)sulfonyl 4-methylbenzene-l-sulfonate (4.86 g, 14.88 mmol) and 2-methylpropan-2-amine (1.96 g, 26.77 mmol) were sequentially added to the above mixture. The resulting mixture was stirred at room temperature for 16 h. The resulting mixture was concentrated under reduced pressure. The residue was purified by reverse phase flash column chromatography with 5% ~ 75% acetonitrile in water (10 mmol/L ammonium bicarbonate) to afford ethyl 2-(tert-butylamino)-5H,6H,7H,8H,9H- cyclohepta[b]pyridine-6-carboxylate (430 mg, 17%) as a brown oil. MS ESI calculated for C17H26N2O2 [M+H]⁺, 291.20; found, 291.25. 'H NMR (400 MHz, DMSO-d₆) 87.06 (d, J = 8.0 Hz, 1H), 6.20 (d, J= 8.0 Hz, 1H), 5.78 (s, 1H), 4.04 (q, J = 7.2 Hz, 2H), 2.83 - 2.65 (m, 4H), 2.45 - 2.27 (m, 1H), 2.11 - 1.97 (m, 1H), 1.90 - 1.75 (m, 2H), 1.52 - 1.38 (m, 1H), 1.36 (s, 9H), 1.17 (t, J = 7.2 Hz, 3H).

Step 8: 1:1 mixture of (R)-2-(tert-butylamino)-6,7,8,9-tetrahydro-5H-cyclohepta[b]pyridine- 6-carboxylic acid and (S)-2-(tert-butylamino)-6,7,8,9-tetrahydro-5H-cyclohepta[b]pyridine-6- carboxylic acid [0760] To a solution of ethyl 2-(tert-butylamino)-5H,6H,7H,8H,9H-cyclohepta[b]pyridine- 6-carboxylate (400 mg, 1.37 mmol) in tetrahydrofuran (2 mL), water (2 mL) and methanol (2 mL) was stirred at room temperature for 16 h. The resulting mixture was concentrated under vacuum to afford lithium 1:1 mixture of (R)-2-(tert-butylamino)-6,7,8,9-tetrahydro-5H- cyclohepta[b]pyridine-6-carboxylic acid and (S)-2-(tert-butylamino)-6,7,8,9-tetrahydro-5H- cyclohepta[b]pyridine-6-carboxylic acid (510 mg, crude) as a yellow solid. MS ESI calculated for C15H22N2O2 [M+H]⁺, 263.17; found, 263.20. 'H NMR (400 MHz, DMSO-d₆) 6 7.01 (d, J = 8.0 Hz, 1H), 6.18 (d, J = 8.0 Hz, 1H), 5.59 (s, 1H), 2.79 - 2.54 (m, 4H), 2.17 - 2.09 (m, 1H), 1.90 - 1.81 (m, 1H), 1.79 - 1.70 (m, 1H), 1.69 - 1.55 (m, 1H), 1.36 (s, 9H), 1.30 - 1.17 (m, 1H).

Intermediate CA3: 1:1 mixture of (S)-4-((tert-butoxycarbonyl)amino)-3,6,8,9-tetrahydro- lH-furo[3,4-d]pyrano[3,4-b]pyridine-8-carboxylic acid and (R)-4-((tert- butoxycarbonyl)amino)-3,6,8,9-tetrahydro-lH-furo[3,4-d]pyrano[3,4-b]pyridine-8-carboxylic acid

Step-1:

[0761] To a stirred solution of 3-(prop-2-yn-l-yloxy)prop-l-yne (40.0 g, 425.02 mmol) in DCM (500 mL) were added NBS (188.36 g, 1058.30 mmol) and AgNO₃ (168.22 g, 990.29 mmol) in portions at 0 °C. The resulting mixture was stirred at room temperature for 16 h. The resulting mixture was filtered, the filter cake was washed with DCM. The filtrate was concentrated under reduced pressure. Then the crude product was diluted with diethyl ether. Then the solids were filtered off, the filter cake was washed with diethyl ether. The filtrate was concentrated under reduced pressure to afford l-bromo-3-((3-bromoprop-2-yn-l- yl)oxy)prop-l-yne (116 g, 97%) as a yellow oil. 'H NMR (400 MHz, DMSO-d₆) 84.28 (s, 4H). Step-2:

[0762] To a stirred mixture of l-bromo-3-((3-bromoprop-2-yn-l-yl)oxy)prop-l-yne (100.0 g, 388.96 mmol) and ethyl carbonocyanidate (78.68 g, 793.94 mmol) in DCE (1 L) was added Cp*RuCl(cod) (7.54 g, 19.84 mmol) at 0 °C under nitrogen atmosphere. The mixture was stirred at room temperature for 16 h. The resulting mixture was concentrated under reduced pressure. The residue was purified by flash column chromatography with 0-30% EtOAc in petroleum ether to afford ethyl 4,7-dibromo-l,3-dihydrofuro[3,4-c]pyridine-6- carboxylate (52.3 g, 37%) as a yellow solid. MS ESI calculated for CioHgBnNCh [M+H]⁺, 349.89; found, 349.75. ’H NMR (400 MHz, DMSO-J₆) 8 (ppm) 5.25 - 5.08 (m, 4H), 4.40 (q, J = 7.2 Hz, 2H), 1.34 (t, J = 7.2 Hz, 3H).

Step-3:

[0763] To a solution of ethyl 4,7-dibromo-l,3-dihydrofuro[3,4-c]pyridine-6-carboxylate (50.0 g, 143.16 mmol) in N-methyl-2-pyrrolidone (500 mL) were added (4- methoxyphenyl)methanamine (29.46 g, 217.74 mmol) at room temperature. The solution was stirred at 120 °C for 16 h. The reaction mixture was quenched with water and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous Na2SC>4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by flash column chromatography with 0-40% EtOAc in petroleum ether to afford ethyl 7-bromo-4-((4-methoxybenzyl)amino)-l,3-dihydrofuro[3,4-c]pyridine-6- carboxylate (38 g, 65%) as a yellow oil. MS ESI calculated for CisHi9BrN2O4 [M+H]⁺, 407.05; found, 406.95. 'H NMR (400 MHz, DMSO-d₆) 8 (ppm) 7.32 - 7.23 (m, 3H), 6.90 - 6.82 (m, 2H), 5.01 - 4.94 (m, 4H), 4.43 (d, J = 5.6 Hz, 2H), 4.32 (q, J = 7.2 Hz, 2H), 3.72 (s, 3H), 1.32 (t, J = 7.2 Hz, 3H).

Step-4:

[0764] To a solution of ethyl 7-bromo-4-((4-methoxybenzyl)amino)-l,3-dihydrofuro[3,4- c]pyridine-6-carboxylate (36 g, 88.39 mmol) and allyltributylstannane (58.54 g, 176.79 mmol) in DMF (360 mL) was added Pd(PPh3)4 (5.11 g, 4.42 mmol) at room temperature under nitrogen atmosphere. The mixture was stirred at 100 °C for 16 h. The reaction mixture was quenched with water and extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered and concentrated under reduced pressure. The residue was purified by flash column chromatography with 0-40% EtOAc in petroleum ether to afford ethyl 7-allyl-4-((4-methoxybenzyl)amino)-l,3- dihydrofuro[3,4-c]pyridine-6-carboxylate (27 g, 82%) as a yellow solid. MS ESI calculated for C21H24N2O4 [M+H]⁺, 369.17; found, 369.35.

Step-5:

[0765] To a stirred mixture of ethyl 7-allyl-4-((4-methoxybenzyl)amino)-l,3- dihydrofuro[3,4-c]pyridine-6-carboxylate (27.0 g, 73.28 mmol) in THF (270 mL), t-BuOH (54 mL) and water (54 mL) were added NMO (10.29 g, 87.94 mmol) and OsO4 (0.93 g, 3.71 mmol) at room temperature under nitrogen atmosphere. The mixture was stirred at room temperature for 1 h. The reaction was quenched by the addition of sodium hyposulfite (sat.) at room temperature and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous Na2SC>4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by flash column chromatography with 0-100% EtOAc in petroleum ether to afford a 1 : 1 mixture of ethyl (R)- 7-(2,3-dihydroxypropyl)-4-((4-methoxybenzyl)amino)-l,3-dihydrofuro[3,4-c]pyridine-6- carboxylate and ethyl (S)-7-(2,3-dihydroxypropyl)-4-((4-methoxybenzyl)amino)-l,3- dihydrofuro[3,4-c]pyridine-6-carboxylate (24.2 g, 82%) as an off-white solid. MS ESI calculated for C21H26N2O6 [M+H]⁺, 403.18; found, 403.30. 'H NMR (400 MHz, DMSO-d₆) 8 (ppm) 7.36 - 7.28 (m, 2H), 6.88 - 6.83 (m, 2H), 6.80 (t, J = 6.0 Hz, 1H), 5.12 - 4.95 (m, 2H), 4.94 - 4.85 (m, 2H), 4.57 - 4.50 (m, 2H), 4.44 (d, 7= 5.6 Hz, 2H), 4.26 (q, 7= 7.2 Hz, 2H), 3.72 (s, 3H), 3.57 - 3.48 (m, 1H), 3.30 - 3.21 (m, 2H), 2.81 - 2.75 (m, 1H), 2.40 - 2.33 (m, 1H), 1.31 (t, J = 7.2 Hz, 3H).

Step-6:

[0766] To a stirred mixture of a 1:1 mixture of ethyl (R)-7-(2,3-dihydroxypropyl)-4-((4- methoxybenzyl)amino)-l,3-dihydrofuro[3,4-c]pyridine-6-carboxylate and ethyl (S)-7-(2,3- dihydroxypropyl)-4-((4-methoxybenzyl)amino)-l,3-dihydrofuro[3,4-c]pyridine-6-carboxylate (14.0 g, 34.78 mmol) and lH-imidazole (3.55 g, 52.18 mmol) in DCM (150 mL) was added tert-butylchlorodiphenylsilane (9.56 g, 34.78 mmol) at room temperature under nitrogen atmosphere. The mixture was stirred at room temperature for 1 h. The reaction mixture was concentrated under reduced pressure. The residue was purified by flash column chromatography with 0 - 50% EtOAc in petroleum ether to afford a 1:1 mixture of ethyl (R)- 7-(3-((tert-butyldiphenylsilyl)oxy)-2-hydroxypropyl)-4-((4-methoxybenzyl)amino)-l,3- dihydrofuro[3,4-c]pyridine-6-carboxylate and ethyl (S)-7-(3-((tert-butyldiphenylsilyl)oxy)-2- hydroxypropyl)-4-((4-methoxybenzyl)amino)-l,3-dihydrofuro[3,4-c]pyridine-6-carboxylate (18.8 g, 84%) as a yellow oil. MS ESI calculated for C37H44N2O6S1 [M+H]⁺, 641.30; found, 641.45. ’H NMR (400 MHz, DMSO-d₆) 8 (ppm) 7.69 - 7.58 (m, 4H), 7.52 - 7.38 (m, 6H), 7.38 - 7.30 (m, 2H), 6.90 - 6.76 (m, 3H), 5.12 - 4.83 (m, 4H), 4.73 (d, J = 5.2 Hz, 1H), 4.44 (d, J = 6.0 Hz, 2H), 4.22 (q, J = 6.8 Hz, 2H), 3.75 - 3.65 (m, 4H), 3.60 - 3.43 (m, 2H), 2.95 - 2.88 (m, 1H), 2.47 - 2.39 (m, 1H), 1.26 (t, J = 6.8 Hz, 3H), 1.00 (s, 9H).

Step-7:

[0767] To a stirred solution of a 1:1 mixture of ethyl (R)-7-(3-((tert- butyldiphenylsilyl)oxy)-2-hydroxypropyl)-4-((4-methoxybenzyl)amino)-l,3-dihydrofuro[3,4- c]pyridine-6-carboxylate and ethyl (S)-7-(3-((tert-butyldiphenylsilyl)oxy)-2-hydroxypropyl)- 4-((4-methoxybenzyl)amino)-l,3-dihydrofuro[3,4-c]pyridine-6-carboxylate (18.8 g, 29.33 mmol) in THF (100 mL) and EtOH (100 mL) were added CaCh (6.51g, 58.67 mmol) and NaBH4 (3.32 g, 88.01 mmol) at 0 °C under nitrogen atmosphere. The mixture was stirred at room temperature for 1 h under nitrogen atmosphere. The reaction mixture was diluted with water at 0 °C and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous Na2SO4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by flash column chromatography with 0-50% EtOAc in petroleum ether to afford a 1:1 mixture of (R)-l-((tert-butyldiphenylsilyl)oxy)-3-(6- (hydroxymethyl)-4-((4-methoxybenzyl)amino)- 1 ,3-dihydrofuro [3 ,4-c]pyridin-7 -yl)propan-2- ol and (S)- l-((tert-butyldiphenylsilyl)oxy)-3-(6-(hydroxymethyl)-4-((4- methoxybenzyl)amino)-l,3-dihydrofuro[3,4-c]pyridin-7-yl)propan-2-ol (14 g, 79%) as a colorless oil. MS ESI calculated for Css^i zOsSi [M+H]⁺, 599.29; found, 599.20.

Step-8:

[0768] To a stirred solution of a 1:1 mixture of (R)-l-((tert-butyldiphenylsilyl)oxy)-3-(6- (hydroxymethyl)-4-((4-methoxybenzyl)amino)-l,3-dihydrofuro[3,4-c]pyridin-7-yl)propan-2- ol and (S)- l-((tert-butyldiphenylsilyl)oxy)-3-(6-(hydroxymethyl)-4-((4- methoxybenzyl)amino)-l,3-dihydrofuro[3,4-c]pyridin-7-yl)propan-2-ol (15.1 g, 25.21 mmol) in THF (50 mL) and toluene (100 mL) was added 2-(tributyl-A,⁵- phosphaneylidene)acetonitrile (CAS No. 157141-27-0) (12.17 g, 50.43 mmol) at room temperature under nitrogen atmosphere. The solution was stirred at 100 °C overnight. The resulting mixture was concentrated under reduced pressure. The residue was purified by flash column chromatography with 0-29% ethyl acetate in petroleum ether to afford a 1:1 mixture of (S)-8-(((tert-butyldiphenylsilyl)oxy)methyl)-N-(4-methoxybenzyl)-3,6,8,9-tetrahydro-lH- furo[3,4-d]pyrano[3,4-b]pyridin-4-amine and (R)-8-(((tert-butyldiphenylsilyl)oxy)methyl)-N- (4-methoxybenzyl)-3,6,8,9-tetrahydro-lH-furo[3,4-d]pyrano[3,4-b]pyridin-4-amine (9.2 g, 62%) as a yellow semi-solid. MS ESI calculated for CssFLo zCLSi [M+H]⁺, 581.28; found, 581.15.

Step-9:

[0769] A 1:1 mixture of (S)-8-(((tert-butyldiphenylsilyl)oxy)methyl)-N-(4- methoxybenzyl)-3,6,8,9-tetrahydro- lH-furo[3,4-d]pyrano[3,4-b]pyridin-4-amine and (R)-8- (((tert-butyldiphenylsilyl)oxy)methyl)-N -(4-methoxybenzyl)-3,6,8 ,9-tetrahydro- 1 H-furo [3 ,4- d]pyrano[3,4-b]pyridin-4-amine (4.7 g, 8.09 mmol) in TFA (50 mL) and trifluoromethanesulfonic acid (0.47 mL, 6.71 mmol) was stirred at room temperature for 16 h. The resulting mixture was concentrated under vacuum. The residue was dissolved in MeOH (40 mL), then K2CO3 (4.47 g, 32.36 mmol) was added. The resulting mixture was stirred at 65 °C for 3 h. Then the reaction mixture was concentrated under vacuum. The residue was purified by flash column chromatography with 0-20% MeOH in DCM to afford a 1:1 mixture of (S)-(4-amino-3,6,8,9-tetrahydro-lH-furo[3,4-d]pyrano[3,4-b]pyridin-8- yl)methanol and (R)-(4-amino-3,6,8,9-tetrahydro-lH-furo[3,4-d]pyrano[3,4-b]pyridin-8- yl)methanol (940 mg, 42%) as a yellow solid. MS ESI calculated for C11H14N2O3 [M+H]⁺, 223.10; found, 223.05. 'H NMR (400 MHz, DMSO- ₆) 5 (ppm) 5.78 (s, 2H), 4.96 - 4.81 (m, 4H), 4.79 (t, J = 5.6 Hz, 1H), 4.50 (s, 2H), 3.71 - 3.61 (m, 1H), 3.57 - 3.42 (m, 2H), 2.39 (d, J = 7.2 Hz, 2H).

[0770] To a solution of a 1:1 mixture of (S)-(4-amino-3,6,8,9-tetrahydro-lH-furo[3,4- d]pyrano[3,4-b]pyridin-8-yl)methanol and (R)-(4-amino-3,6,8,9-tetrahydro-lH-furo[3,4- d]pyrano[3,4-b]pyridin-8-yl)methanol (940 mg, 4.23 mmol) and BOC2O (3.69 g, 16.92 mmol) in THF (10 mL) were added DMAP (155 mg, 1.27 mmol) and TEA (2.57 g, 25.38 mmol) at room temperature. The mixture was stirred at room temperature for 16 h. The reaction mixture was concentrated under vacuum. The residue was purified by reverse phase flash column chromatography with 10% ~ 90% MeCN in water (10 mmol/L NH4HCO3) to afford a 1:1 mixture of tert-butyl (S)-(tert-butoxycarbonyl)(8-(((tert-butoxycarbonyl)oxy)methyl)- 3,6,8,9-tetrahydro-lH-furo[3,4-d]pyrano[3,4-b]pyridin-4-yl)carbamate and tert-butyl (R)- (tert-butoxycarbonyl)(8-(((tert-butoxycarbonyl)oxy)methyl)-3,6,8,9-tetrahydro-lH-furo[3,4- d]pyrano[3,4-b]pyridin-4-yl)carbamate (1.2 g, 46%) as a yellow solid. MS ESI calculated for C26H38N2O9 [M+H]⁺, 523.26; found, 523.45.

Step-11:

[0771] To a stirred solution of a 1 :1 mixture of tert-butyl (S)-(tert-butoxycarbonyl)(8- (((tert-butoxycarbonyl)oxy)methyl)-3,6,8,9-tetrahydro-lH-furo[3,4-d]pyrano[3,4-b]pyridin- 4-yl)carbamate and tert-butyl (R)-(tert-butoxycarbonyl)(8-(((tert- butoxycarbonyl)oxy)methyl)-3,6,8,9-tetrahydro-lH-furo[3,4-d]pyrano[3,4-b]pyridin-4- yl)carbamate (1.2 g, 2.29 mmol) in MeOH (48 mL) was added NaOH (14.4 mL, 25% aqueous solution) at room temperature. The mixture was stirred at room temperature for 1 h. The organic solvent was concentrated under reduced pressure. The residue was quenched with water and extracted with DCM. The combined organic layers were washed with brine, dried over anhydrous NaiSCk. After filtration, the filtrate was concentrated under reduced pressure to afford a 1:1 mixture of tert-butyl (S)-(8-(hydroxymethyl)-3,6,8,9-tetrahydro-lH- furo[3,4-d]pyrano[3,4-b]pyridin-4-yl)carbamate and tert-butyl (R)-(8-(hydroxymethyl)- 3,6,8,9-tetrahydro-lH-furo[3,4-d]pyrano[3,4-b]pyridin-4-yl)carbamate (740 mg, crude) as a colorless oil. MS ESI calculated for C16H22N2O5 [M+H]⁺, 323.15; found, 323.20. 'H NMR (400 MHz, DMSO-de) 5 (ppm) 9.54 (s, 1H), 5.06 - 4.83 (m, 5H), 4.70 - 4.60 (m, 2H), 3.77 - 3.69 (m, 1H), 3.59 - 3.48 (m, 2H), 2.60 - 2.53 (m, 2H), 1.44 (s, 9H).

Step- 12:

CA3

[0772] To a stirred a 1:1 mixture of tert-butyl (S)-(8-(hydroxymethyl)-3,6,8,9-tetrahydro- lH-furo[3,4-d]pyrano[3,4-b]pyridin-4-yl)carbamate and tert-butyl (R)-(8-(hydroxymethyl)- 3,6,8,9-tetrahydro-lH-furo[3,4-d]pyrano[3,4-b]pyridin-4-yl)carbamate (350 mg, 1.08 mmol) in ACN (4 mL) and H2O (2 mL) were added TEMPO (68 mg, 0.43 mmol) and BAIB (420 mg, 1.30 mmol) at 0 °C. The resulting mixture was stirred at room temperature for 16 h. The reaction mixture was purified directly by reverse phase flash column chromatography with 0- 25% MeCN in water (10 mmol/L NH4HCO3) to afford a 1:1 mixture of (S)-4-((tert- butoxycarbonyl)amino)-3,6,8,9-tetrahydro-lH-furo[3,4-d]pyrano[3,4-b]pyridine-8-carboxylic acid and (R)-4-((tert-butoxycarbonyl)amino)-3,6,8,9-tetrahydro- lH-furo[3,4-d]pyrano[3,4- b]pyridine-8-carboxylic acid (CA3) (75 mg, 20%) as an off-white solid. MS ESI calculated for C16H20N2O6 [M+H]⁺, 337.13; found, 337.05. 'H NMR (400 MHz, DMSO-d₆) 8 (ppm) 9.52 (s, 1H), 5.08 - 4.87 (m, 4H), 4.85 - 4.50 (m, 2H), 4.02 - 3.97 (m, 1H), 2.93 - 2.63 (m, 2H), 1.44 (s, 9H).

Intermediate CA3 isomer 1: rel-(R)-4-((tert-butoxycarbonyl)amino)-3,6,8,9-tetrahydro-lH- furo[3,4-d]pyrano[3,4-b]pyridine-8-carboxylic acid, isomer 1:

Intermediate CA3 isomer 2: rel-(R)-4-((tert-butoxycarbonyl)amino)-3,6,8,9-tetrahydro-lH- furo[3,4-d]pyrano[3,4-b]pyridine-8-carboxylic acid, isomer 2:

CA3 isomer 2

[0773] Intermediate CA3 (810 mg) was separated by Prep-chiral HPLC with the following conditions: [Column: CHIRALPAK IE, 2*25 cm, 5 pm; Mobile Phase A: Hex (0.1% TFA)— HPLC, Mobile Phase B: MeOH: DCM=1: 1— HPLC; Flow rate: 20 mL/min; Gradient (B%): 50% B to 50% B in 11 min; Wave Length: 220/254 nm; RTl(min): 5.41; RT2(min): 9.63; Sample Solvent: MeOH: DCM=1: 1— HPLC] to afford rel-(R)-4-((tert- butoxycarbonyl)amino)-3,6,8,9-tetrahydro-lH-furo[3,4-d]pyrano[3,4-b]pyridine-8-carboxylic acid isomer 1 (CA3 isomer 1) (381 mg) as a white solid with retention time at 5.41 minute. MS ESI calculated for Ci₆H₂oN₂0₆ [M+H]⁺, 337.13; found, 337.05 'H NMR (400 MHz, DMSO-J₆) 8 (ppm) 9.61 (s, 1H), 5.10 - 4.83 (m, 4H), 4.80 - 4.68 (m, 2H), 4.45 - 4.42 (m, 1H), 2.88 - 2.60 (m, 2H), 1.44 (s, 9H). Absolute stereochemistry was not determined.

[0774] The chiral separation also afforded rel-(R)-4-((tert-butoxycarbonyl)amino)-3, 6,8,9- tetrahydro-lH-furo[3,4-d]pyrano[3,4-b]pyridine-8-carboxylic acid isomer 2 (CA3 isomer 2) (365 mg) as a white solid with retention time at 9.63 minute. MS ESI calculated for CI₆H₂ON₂0₆ [M+H]⁺, 337.13; found, 337.05. 'H NMR (400 MHz, DMSO-d₆) 8 (ppm) 9.62 (s, 1H), 5.08 - 4.80 (m, 4H), 4.80 - 4.68 (m, 2H), 4.45 - 4.42 (m, 1H), 2.90 - 2.68 (m, 2H), 1.44 (s, 9H).

[0775] Absolute stereochemistry of CA3 isomer 1 was determined based on single crystal X-ray crystallography of Example 33 prepared using CA3 isomer 1. Accordingly, CA3 isomer 1 (S-configuration) and CA3 isomer 2 (R-configuration) are each represented by the respective structures:

Isomer 1 _an(| Isomer 2

Intermediate CA4: 1:1 mixture of (S)-4-amino-7-(tert-butoxycarbonyl)-l,3,6,7,8,9- hexahydrofuro[3,4-c][l,7]naphthyridine-8-carboxylic acid and (R)-4-amino-7-(tert- butoxy carbonyl)-! ,3,6,7,8,9-hexahydrofuro[3,4-c] [l,7]naphthyridine-8-carboxylic acid

CA4

Step-1:

[0776] To a stirred solution of 4-oxotetrahydrofuran-3-carbonitrile (25.0 g, 225.02 mmol) and DIEA (34.9 g, 270.02 mmol) in DCM (500 mL) were added (trifhioromethane)sulfonyl trifluoromethanesulfonate (63.4 g, 225.02 mmol) at -78 °C under nitrogen atmosphere. The resulting mixture was stirred at room temperature for 2 h. The resulting mixture was concentrated under vacuum. The mixture was diluted with ethyl acetate and washed with NaHCCh (sat.). The organic layer was dried over anhydrous Na2SO4, filtered and concnetrated under vacuum. The residue was purified by flash column chromatography with 0-60% ethyl acetate in petroleum ether to afford 4-cyano-2,5-dihydrofuran-3-yl trifluoromethanesulfonate (40.0 g, 73%) as a brown oil. MS ESI calculated for C6H4F3NO4S [M+l]⁺, 243.98; found, 244.20.

Step-2:

[0777] A mixture of methyl 5-aminopyridine-2-carboxylate (25.00 g, 164.31 mmol) and 4,4,5,5-tetramethyl-l,3,2-dioxaborolane (31.54 g, 246.46 mmol) in anhydrous THF (200 mL) was stirred at 50 °C for 1 h under nitrogen atmosphere. The reaction mixture was cooled to 25 °C and then added to a mixture of Bis(pinacolato)diboron (20.86 g, 82.15 mmol), dtbppy (1.32 g, 4.93 mmol) and [Ir(COD)(OMe)]₂ (1.63 g, 2.47 mmol) in anhydrous THF (200 mL) at 25 °C under nitrogen atmosphere. The mixture was stirred at 80 °C for 16 h. The organic solvent was removed under vacuum. The residue was triturated with n-heptane and tert-Butyl methyl ether (1/1) to afford methyl 5-amino-4-(4,4,5,5-tetramethyl-l,3,2-dioxaborolan-2- yl)pyridine-2-carboxylate (62.4 g, crude) as a brown solid. MS ESI calculated for C13H19BN2O4 [M+H]⁺, 279.14; found, 279.15. 'H NMR (400 MHz, Chloroform-^ ) 5 8.30 (s, 1H), 8.11 (s, 1H), 5.26 (br, 2H), 3.94 (s, 3H), 1.37 (s, 12H).

Step-3:

[0778] To a stirred solution of 4-cyano-2,5-dihydrofuran-3-yl trifluoromethanesulfonate (40.0 g, 164.50 mmol) and methyl 5-amino-4-(4,4,5,5-tetramethyl-l,3,2-dioxaborolan-2- yl)picolinate (45.7 g, 164.50 mmol) in dioxane (500 mL) and H2O (50 mL) was added Pd(dppf)C12-CH2C12 (13.4 g, 16.45 mmol) and K2CO3 (27.2 g, 197.40 mmol). The resulting mixture was stirred at 80 °C for 2 h. The mixture was diluted by water. The suspension was filtered. The filter cake was collected and dried under vacuum to afford methyl 4-amino-l ,3- dihydrofuro[3,4-c][l,7]naphthyridine-8-carboxylate (32.0 g, 79%) as a brown solid. MS ESI calculated for C12H11N3O3 [M+H]⁺, 246.08; found, 246.20. 'H NMR (300 MHz, DMSO-J₆) 3 8.90 (s, 1H), 8.16 (s, 1H), 7.24 (s, 2H), 5.39 (s, 2H), 5.04 (s, 2H), 3.88 (s, 3H).

Step-4:

[0779] To a mixture of 4-amino-lH,3H-furo[3,4-c]l,7-naphthyridine-8-carbonitrile (1.8 g, 8.48 mmol) in H2O (30 mL) was added NaOH (1.36 g, 33.92 mmol) at 25 °C. The mixture was stirred at 85 °C for 16 h. The mixture was cooled down to 25 °C. The reaction mixture was acidified by HC1 (cone.) dropwise at 25 °C. The precipitated solids were collected by filtration and washed with water and i-PrOH, then dried under vacuum to afford 4-amino- lH,3H-furo[3,4-c]l,7-naphthyridine-8-carboxylic acid (1.1 g, 55%) as a yellow solid. MS ESI calculated for C11H9N3O3 [M+H]⁺, 232.06; found, 232.10.

[0780] To a solution of 4-amino-lH,3H-furo[3,4-c]l,7-naphthyridine-8-carboxylic acid (1.0 g, 4.32 mmol) in AcOH (10 mL) was added Platinum(IV)oxide (100 mg). The mixture was hydrogenated at room temperature for 16 h under hydrogen atmosphere with a hydrogen balloon. After completion, the mixture was filtered through a Celite pad. The filtrate was concentrated under reduced pressure. The resulting residue was purified by reverse phase flash column chromatography with 5-70% acetonitrile in water to afford a 1:1 mixture of (S)- 4-amino-l,3,6,7,8,9-hexahydrofuro[3,4-c][l,7]naphthyridine-8-carboxylic acid and (R)-4- amino-l,3,6,7,8,9-hexahydrofuro[3,4-c][l,7]naphthyridine-8-carboxylic acid (1.0 g, 98%) as a yellow oil. MS ESI calculated for C11H13N3O3 [M+H]⁺, 236.10; found, 236.10.

Step-6:

[0781] To a stirred solution of a 1:1 mixture of (S)-4-amino-l,3,6,7,8,9-hexahydrofuro[3,4- c][l,7]naphthyridine-8-carboxylic acid and (R)-4-anrino-l,3,6,7,8,9-hexahydrofuro[3,4- c][l,7]naphthyridine-8-carboxylic acid (180 mg, 0.76 mmol) in 1,4-dioxane (1.6 mL) and H2O (0.4 mL) were added NaHCCh (192 mg, 2.29 mmol) and BOC2O (200 mg, 0.91 mmol) at 0 °C. The resulting mixture was stirred at room temperature for 16 h. The mixture was concentrated under reduced pressure. The residue was purified by reverse phase flash column chromatography with 5-70% acetonitrile in water to afford a 1:1 mixture of (S)-4-amino-7- (tert-butoxycarbonyl)-l,3,6,7,8,9-hexahydrofuro[3,4-c][l,7]naphthyridine-8-carboxylic acid and (R)-4-amino-7-(tert-butoxy carbonyl)- 1 ,3,6,7,8,9-hexahydrofuro[3,4- c][l,7]naphthyridine-8-carboxylic acid (CA4) (89 mg, 22%) as a yellow solid. MS ESI calculated for C16H21N3O5 [M+H]⁺, 336.15; found, 336.10. 'H NMR (400 MHz, DMSO-d₆) 3 5.80 (s, 2H), 4.91 - 4.78 (m, 4H), 4.76 - 4.14 (m, 3H), 2.93 - 2.67 (m, 2H), 1.44 and 1.40 (s, 9H).

Intermediate CA4 isomer 1: (S)-4-amino-7-(tert-butoxycarbonyl)-l,3,6,7,8,9- hexahydrofuro[3,4-c][l,7]naphthyridine-8-carboxylic acid isomer 1:

Intermediate CA4 isomer 2: (R)-4-amino-7-(tert-butoxycarbonyl)-l,3,6,7,8,9- hexahydrofuro[3,4-c][l,7]naphthyridine-8-carboxylic acid isomer 2

Isomer 2

Step-1:

[0782] A mixture of methyl 4-amino- 1 ,3-dihydrofuro[3,4-c] [ 1 ,7]naphthyridine-8- carboxylate (7 g, 28.54 mmol) and PtCh (1.4 g, 6.17 mmol) in TFA (140 mL) was stirred at 20 °C for 5 h under hydrogen atmosphere. The resulting mixture was filtered, the filter cake was washed with MeOH. The filtrate was concentrated under vacuum to afford a 1:1 mixture of methyl (S)-4-amino-l,3,6,7,8,9-hexahydrofuro[3,4-c][l,7]naphthyridine-8-carboxylate and methyl (R)-4-amino-l,3,6,7,8,9-hexahydrofuro[3,4-c][l,7]naphthyridine-8-carboxylate (9.0 g, crude) as a brown solid. MS ESI calculated for C12H15N3O3 [M+H]⁺, 250.11; found, 250.25.

Step-2:

[0783] To a stirred solution of a 1:1 mixture of methyl (S)-4-amino-l,3,6,7,8,9- hexahydrofuro[3,4-c][l,7]naphthyridine-8-carboxylate and methyl (R)-4-amino-l,3,6,7,8,9- hexahydrofuro[3,4-c][l,7]naphthyridine-8-carboxylate (6.0 g, 24.07 mmol) and NaiCOs (12.76 g, 120.35 mmol) in THF (150 mL) and H₂O (30 mL) was added Boc₂O (5.25 g, 24.07 mmol). The mixture was stirred at 20 °C for 16 h. The mixture was diluted with water and extracted with ethyl acetate. The residue was purified by reverse phase flash column chromatography with 5-50% acetonitrile in water to afford a 1:1 mixture of 7-(tert-butyl) 8- methyl (S)-4-amino-3,6,8,9-tetrahydrofuro[3,4-c][l,7]naphthyridine-7,8(lH)-dicarboxylate and 7-(tert-butyl) 8-methyl (R)-4-amino-3,6,8,9-tetrahydrofuro[3,4-c][l,7]naphthyridine- 7,8(lH)-dicarboxylate (3.0 g, 33%) as a light brown solid. MS ESI calculated for C17H23N3O5

[M+H]⁺, 350.16; found, 350.20.

Step-3:

[0784] A 1:1 mixture of 7-(tert-butyl) 8-methyl (S)-4-amino-3,6,8,9-tetrahydrofuro[3,4- c][l,7]naphthyridine-7,8(lH)-dicarboxylate and 7-(tert-butyl) 8-methyl (R)-4-amino-3, 6,8,9- tetrahydrofuro[3,4-c][l,7]naphthyridine-7,8(lH)-dicarboxylate (950 mg) was separated by prep-chiral SFC with the following conditions: [Column: CHIRALPAK IG, 5*25 cm, 10 pm; Mobile Phase A: CO2, Mobile Phase B: MEOH; Flow rate: 200 mL/min; Gradient (B%): isocratic 50% B; Column Temperature (°C): 35; Back Pressure(bar): 100; Wave Length: 220 nm; RT1 (min): 3.99; RT2 (min): 5.08; Sample Solvent: MEOH] to afford 7-(tert-butyl) 8- methyl (S)-4-amino-3,6,8,9-tetrahydrofuro[3,4-c][l,7]naphthyridine-7,8(lH)-dicarboxylate isomer 1 (180 mg, 18%) as a white solid with retention time at 3.99 minute. MS ESI calculated for C17H23N3O5 [M+H]⁺, 350.16; found, 350.20.

[0785] The chiral separation also afforded 7-(tert-butyl) 8-methyl (R)-4-amino-3, 6,8,9- tetrahydrofuro[3,4-c][l,7]naphthyridine-7,8(lH)-dicarboxylate isomer 2 (350 mg, 36%) as a white solid with retention time at 5.08 minute. MS ESI calculated for C17H23N3O5 [M+H]⁺, 350.16; found, 350.20.

[0786] A solution of 7-(tert-butyl) 8-methyl (S)-4-amino-3,6,8,9-tetrahydrofuro[3,4- c][l,7]naphthyridine-7,8(lH)-dicarboxylate isomer 1 (180 mg, 0.51 mmol) and Trimethyltin hydroxide (279 mg, 1.54 mmol) in DCE (5 mL) was stirred at 90 °C for 16 h under nitrogen atmosphere. The mixture was concentrated under vacuum. The residue was purified by reverse phase flash column chromatography with 5-100% acetonitrile in water to afford (S)- 4-amino-7-(tert-butoxycarbonyl)-l,3,6,7,8,9-hexahydrofuro[3,4-c][l,7]naphthyridine-8- carboxylic acid isomer 1 (CA4 isomer 1) (150 mg, 86%) as a yellow solid. MS ESI calculated for C16H21N3O5 [M+H]⁺, 336.15; found, 336.10. 'H NMR (400 MHz, DMSO-d₆) 8 5.80 (s, 2H), 4.91 - 4.78 (m, 4H), 4.76 - 4.14 (m, 3H), 2.93 - 2.67 (m, 2H), 1.44 and 1.40 (s, 9H).

Absolute stereochemistry was assigned in view of the absolute stereochemistry of CA4 isomer 2.

Step-5:

[0787] A solution of 7-(tert-butyl) 8-methyl (R)-4-amino-3,6,8,9-tetrahydrofuro[3,4- c][l,7]naphthyridine-7,8(lH)-dicarboxylate (340 mg, 0.97 mmol) and Trimethyltin hydroxide (527 mg, 2.91 mmol) in DCE (5 mL) was stirred at 90 °C for 16 h. The mixture was concentrated under vacuum. The residue was purified by reverse phase flash column chromatography with 5-100% acetonitrile in water to afford (R)-4-amino-7-(tert- butoxycarbonyl)-l,3,6,7,8,9-hexahydrofuro[3,4-c][l,7]naphthyridine-8-carboxylic acid isomer 2 (CA4 isomer 2) (180 mg, 55%) as a yellow solid. MS ESI calculated for C16H21N3O5 [M+H]⁺, 336.15; found, 336.10. 'H NMR (400 MHz, DMSO-d₆) 8 5.80 (s, 2H), 4.91 - 4.78 (m, 4H), 4.76 - 4.14 (m, 3H), 2.93 - 2.67 (m, 2H), 1.44 and 1.40 (s, 9H).

Absolute stereochemistry was determined by single crystal X-ray crystallography of Example 31, prepared using CA4 isomer 2.

Intermediate CA5 isomer 1: rel-(3R,8R)-4-amino-3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4- c]quinoline-8-carboxylic acid isomer 1

Intermediate CA5 isomer 2: rel-(3R,8R)-4-amino-3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4- c]quinoline-8-carboxylic acid isomer 2

Intermediate CA5 isomer 3: rel-(3R,8R)-4-amino-3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4- c]quinoline-8-carboxylic acid isomer 3

Intermediate CA5 isomer 4: rel-(3R,8R)-4-amino-3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4- c]quinoline-8-carboxylic acid isomer 4

Step-1:

[0788] To a solution of methyl 2-hydroxyacetate (50.0 g, 555.07 mmol) in THF (250 mL) was added sodium hydride (60% in mineral oil) (6.66 g, 166.53 mmol) at 0 °C. The mixture was stirred at 0 °C for 5 min under nitrogen atmosphere. Then (E)-but-2-enenitrile (44.69 g, 666.08 mmol) was added dropwise over 30 min at 65 °C under nitrogen atmosphere. The reaction was quenched with NaOH (250 mL, 2N) at room temperature. The mixture was extracted with EtiO. The aqueous layer was acidified to pH 1 with HC1 (cone.) and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered and concentrated under vacuum. The residue was purified by flash column chromatography with 0 ~ 25% EtOAc in petroleum ether to afford 2-methyl- 4-oxotetrahydrofuran-3-carbonitrile (30.6 g, 44%) as a fight yellow oil. MS ESI calculated for C6H7NO2 [M-l]-, 124.05; found, 123.90.

Step-2:

[0789] To a solution of 2-methyl-4-oxotetrahydrofuran-3-carbonitrile (30.6 g, 244.55 mmol) and DIEA (63.09 g, 489.10 mmol) in DCM (612 mL) was added TfiO (96.59 g, 342.37 mmol) at -78 °C. The mixture was stirred at -78 °C for 30 min. The reaction mixture was quenched with addition of water and extracted with DCM. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered and concentrated under vacuum. The residue was dissolved in Et?O at room temperature and stirred at room temperature for 15 min. The resulting mixture was filtered, the filter cake was washed with Et2O. The filtrate was concentrated under reduced pressure to afford 4-cyano-5-methyl-2,5- dihydrofuran-3-yl trifluoromethanesulfonate (57.6 g, crude) as a brown oil. The crude product was used in the next step directly without further purification. 'H NMR (300 MHz, DMSO-de) 5 (ppm) 5.27 - 5.15 (m, 1H), 4.92 - 4.86 (m, 2H), 1.38 (d, J = 6.3 Hz, 3H).

Step-3:

[0790] A mixture of 4-cyano-5-methyl-2,5-dihydrofuran-3-yl trifluoromethanesulfonate (57.6 g, 223.96 mmol), methyl 4-amino-3-(4,4,5,5-tetramethyl-l,3,2-dioxaborolan-2- yl)benzoate (62.06 g, 223.96 mmol), K3PO4 (142.62 g, 671.90 mmol) and Pd(dppf)Ch- CH2CI2 (18.3 g, 22.39 mmol) in 1,4-dioxane (2300 mL) and H2O (115 mL) was stirred at 90 °C for 16 h under nitrogen atmosphere. The reaction mixture was diluted with addition of water and extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered and concentrated under vacuum. The residue was purified by flash column chromatography with 0-50% EtOAc in petroleum ether to afford a 1:1 mixture of methyl (R)-4-amino-3-methyl-l,3-dihydrofuro[3,4-c]quinoline-8-carboxylate and methyl (S)-4-amino-3-methyl-l,3-dihydrofuro[3,4-c]quinoline-8-carboxylate (50 g, 87%) as an orange solid. MS ESI calculated for C14H14N2O3 [M+H]⁺, 259.10; found, 259.10. 'H NMR (400 MHz, DMSO- d₆~) 8 8.11 (d, J = 2.0 Hz, 1H), 8.01 (dd, J = 8.8, 2.0 Hz, 1H), 7.61 (d, J= 8.8 Hz, 1H), 7.01 (s, 2H), 5.49 - 5.28 (m, 3H), 3.87 (s, 3H), 1.42 (d, 7 = 6.0 Hz, 3H). Step-4:

[0791] A mixture of methyl 4-amino-3-methyl-l ,3-dihydrofuro[3,4-c]quinoline-8- carboxylate (50 g, 193.05 mmol), EtaN (154.21 g, 1523.94 mmol) and Acetic anhydride (103.72 g, 1015.96 mmol) in DMF (500 mL) was stirred at 90 °C for 16 h. The reaction mixture was diluted by the addition of water. The precipitated solids were collected by filtration and washed with EtOAc. The filtrate was extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered and concentrated under vacuum.

[0792] Combined the residue and the precipitated solids and dissolved in TFA (570 mL). PtO2 (36.32 g, 160.00 mmol) was added to the mixture at room temperature under nitrogen atmosphere. The resulting solution was stirred at room temperature for 16 h under hydrogen atmosphere. The reaction mixture was concentrated under vacuum. The residue was basified with NaHCCh (sat.) to pH 8 and extracted with DCM. The combined organic layers were filtered, the filter cake was washed with DCM/MeOH (1:1, v/v). The filtrate was washed with brine, dried over anhydrous sodium sulfate, filtered and concentrated under vacuum. The residue was purified by flash column chromatography with 0-33% EtOAc in petroleum ether to afford a 1 : 1 :3:3 mixture of methyl (3R,8S)-4-acetamido-3-methyl-l,3,6,7,8,9- hexahydrofuro[3,4-c]quinoline-8-carboxylate and methyl (3R,8R)-4-acetamido-3-methyl- l,3,6,7,8,9-hexahydrofuro[3,4-c]quinoline-8-carboxylate and methyl (3S,8S)-4-acetamido-3- methyl-l,3,6,7,8,9-hexahydrofuro[3,4-c]quinoline-8-carboxylate and methyl (3S,8R)-4- acetamido-3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4-c]quinoline-8-carboxylate (26.8 g, 47%) as a brown solid. MS ESI calculated for C16H20N2O4 [M+H]⁺, 305.14; found, 305.10.

Step-5:

[0793] A 1 : 1 :3:3 mixture of methyl (3R,8S)-4-acetamido-3-methyl-l,3,6,7,8,9- hexahydrofuro[3,4-c]quinoline-8-carboxylate and methyl (3R,8R)-4-acetamido-3-methyl- 1 ,3,6,7,8,9-hexahydrofuro[3,4-c]quinoline-8-carboxylate and methyl (3S,8S)-4-acetamido-3- methyl-l,3,6,7,8,9-hexahydrofuro[3,4-c]quinoline-8-carboxylate and methyl (3S,8R)-4- acetamido-3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4-c]quinoline-8-carboxylate (7.2 g) was separated by Prep-chiral SFC with the following conditions: [Column: CHIRAL ART Cellulose-SB, 5*25 cm, 10 pm; Mobile Phase A: CO2, Mobile Phase B: IPA (0.1% 7M NH3- MeOH); Flow rate: 200 mL/min; Gradient: isocratic 50% B; Column Temperature(°C): 35; Back Pressure(bar): 100; Wave Length: 220 nm; RTl(min): 2.88; RT2(min): 4.64; RT3(min): 6.19] to afford fraction A (3.6 g) with retention time at 2.88 minute.

[0794] The chiral separation also afforded rel-methyl (3R,8R)-4-acetamido-3-methyl- l,3,6,7,8,9-hexahydrofuro[3,4-c]quinoline-8-carboxylate isomer 3 (2 g) as a yellow solid with retention time at 4.64 minute and rel-methyl (3R,8R)-4-acetamido-3-methyl-l,3,6,7,8,9- hexahydrofuro[3,4-c]quinoline-8-carboxylate isomer 4 (700 mg) as a yellow solid with retention time at 6.19 minute.

[0795] The fraction A (3.6 g) was further separated by Prep-chiral SFC with the following conditions: [Column: CHIRAL ART Cellulose-SC, 3*25 cm, 5 pm; Mobile Phase A: CO2, Mobile Phase B: MeOH: ACN=1: 1(0.1% 2M NH₃-MeOH); Flow rate: 100 mL/min;

Gradient: isocratic 25% B; RTl(min): 5; RT2(min): 6; Sample Solvent: MeOH] to afford rel- methyl (3R,8R)-4-acetamido-3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4-c]quinoline-8- carboxylate isomer 1 (800 mg) as a yellow solid with retention time at 5 minute and rel- methyl (3R,8R)-4-acetamido-3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4-c]quinoline-8- carboxylate isomer 2 (2.0 g) as a yellow solid with retention time at 6 minute.

[0796] rel-methyl (3R,8R)-4-acetamido-3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4- c]quinoline-8-carboxylate isomer 1: MS ESI calculated for C16H20N2O4 [M+H]⁺, 305.14; found, 305.15. 'H NMR (300 MHz, DMSO-A) 3 (ppm) 10.34 (s, 1H), 5.42 - 5.32 (m, 1H), 5.08 - 4.82 (m, 2H), 3.66 (s, 3H), 2.98 - 2.66 (m, 5H), 2.30 - 2.12 (m, 1H), 2.04 (s, 3H), 1.93

- 1.78 (m, 1H), 1.14 (d, J = 6.3 Hz, 3H). Absolute stereochemistry was not determined.

[0797] rel-methyl (3R,8R)-4-acetamido-3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4- c]quinoline-8-carboxylate isomer 2: MS ESI calculated for C16H20N2O4 [M+H]⁺, 305.14; found, 305.15. 'H NMR (300 MHz, DMSO-J₆) 3 (ppm) 10.33 (s, 1H), 5.42 - 5.32 (m, 1H), 5.05 - 4.85 (m, 2H), 3.66 (s, 3H), 3.02 - 2.68 (m, 5H), 2.30 - 2.11 (m, 1H), 2.04 (s, 3H), 1.96

- 1.78 (m, 1H), 1.15 (d, J = 6.3 Hz, 3H). Absolute stereochemistry was not determined.

[0798] rel-methyl (3R,8R)-4-acetamido-3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4- c]quinoline-8-carboxylate isomer 3: MS ESI calculated for C16H20N2O4 [M+H]⁺, 305.14; found, 305.15. 'H NMR (300 MHz, DMSO-J₆) 3 10.29 (s, 1H), 5.42 - 5.30 (m, 1H), 5.02 - 4.88 (m, 2H), 3.67 (s, 3H), 2.95 - 2.70 (m, 5H), 2.31 - 2.14 (m, 1H), 2.05 (s, 3H), 1.96 - 1.75 (m, 1H), 1.16 (d, J = 6.3 Hz, 3H). Absolute stereochemistry was not determined.

[0799] rel-methyl (3R,8R)-4-acetamido-3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4- c]quinoline-8-carboxylate isomer 4: MS ESI calculated for C16H20N2O4 [M+H]⁺, 305.14; found, 305.15. 'H NMR (300 MHz, DMSO-J₆) 3 (ppm) 10.30 (s, 1H), 5.42 - 5.33 (m, 1H), 5.11 - 4.78 (m, 2H), 3.67 (s, 3H), 3.00 - 2.65 (m, 5H), 2.30 - 2.12 (m, 1H), 2.04 (s, 3H), 1.95

- 1.77 (m, 1H), 1.15 (d, J = 6.3 Hz, 3H). Absolute stereochemistry was not determined.

Step-6:

[0800] A solution of rel-methyl (3R,8R)-4-acetamido-3-methyl-l,3,6,7,8,9- hexahydrofuro[3,4-c]quinoline-8-carboxylate isomer 1 (200 mg, 0.65 mmol) and HC1 (cone.) (6 mL) was stirred at 100 °C for 1 h. The reaction mixture was concentrated under reduced pressure to afford rel-(3R,8R)-4-amino-3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4-c]quinoline- 8-carboxylic acid isomer 1 (CA5 isomer 1) (140 mg, crude) as a yellow solid. MS ESI calculated for C13H16N2O3 [M+H]⁺, 249.12; found, 249.15. Absolute stereochemistry was not determined.

Step-7:

[0801] A solution of rel-methyl (3R,8R)-4-acetamido-3-methyl-l,3,6,7,8,9- hexahydrofuro[3,4-c]quinoline-8-carboxylate isomer 2 (200 mg, 0.65 mmol) and HC1 (cone.) (6 mL) was stirred at 100 °C for 1 h. The reaction mixture was concentrated under reduced pressure to afford rel-(3R,8R)-4-amino-3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4-c]quinoline- 8-carboxylic acid isomer 2 (CA5 isomer 2) (180 mg, crude) as a yellow solid. MS ESI calculated for C13H16N2O3 [M+H]⁺, 249.12; found, 249.15. Absolute stereochemistry was not determined.

[0802] A solution of rel-methyl (3R,8R)-4-acetamido-3-methyl-l,3,6,7,8,9- hexahydrofuro[3,4-c]quinoline-8-carboxylate isomer 3 (200 mg, 0.65 mmol) and HC1 (cone.) (6 mL) was stirred at 100 °C for 1 h. The reaction mixture was concentrated under reduced pressure to afford rel-(3R,8R)-4-amino-3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4-c]quinoline- 8-carboxylic acid isomer 3 (CA5 isomer 3) (170 mg, crude) as a yellow solid. MS ESI calculated for C13H16N2O3 [M+H]⁺, 249.12; found, 249.10. Absolute stereochemistry was not determined.

Step-9:

[0803] A solution of rel-methyl (3R,8R)-4-acetamido-3-methyl-l,3,6,7,8,9- hexahydrofuro[3,4-c]quinoline-8-carboxylate isomer 4 (100 mg, 0.33 mmol) and HC1 (cone.) (3 mL) was stirred at 100 °C for 1 h. The reaction mixture was concentrated under reduced pressure to afford rel-(3R,8R)-4-amino-3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4-c]quinoline- 8-carboxylic acid isomer 4 (CA5 isomer 4) (140 mg, crude) as a yellow solid. MS ESI calculated for C13H16N2O3 [M+H]⁺, 249.12; found, 249.05. Absolute stereochemistry was not determined.

Intermediate CA6 isomer 1: rel-(3R,8R)-4-amino-7-(tert-butoxycarbonyl)-3-methyl- l,3,6,7,8,9-hexahydrofuro[3,4-c][l,7]naphthyridine-8-carboxylic acid isomer 1 l^{somer 1} and,

Intermediate CA6 isomer 2: rel-(3R,8R)-4-amino-7-(tert-butoxycarbonyl)-3-methyl- l,3,6,7,8,9-hexahydrofuro[3,4-c][l,7]naphthyridine-8-carboxylic acid isomer 2

Intermediate CA6 isomer 3: (3R,8R)-4-amino-7-(tert-butoxycarbonyl)-3-methyl-l , 3, 6, 7,8,9- hexahydrofuro[3,4-c][l,7]naphthyridine-8-carboxylic acid isomer 3

Intermediate CA6 isomer 4: rel-(3R,8R)-4-amino-7-(tert-butoxycarbonyl)-3-methyl- l,3,6,7,8,9-hexahydrofuro[3,4-c][l,7]naphthyridine-8-carboxylic acid isomer 4 [0804] To a stirred solution of 4-cyano-5-methyl-2,5-dihydrofuran-3-yl trifluoromethanesulfonate (83.20 g, 322.73 mmol) and methyl 5-amino-4-(4, 4,5,5- tetramethyl-l,3,2-dioxaborolan-2-yl)pyridine-2-carboxylate (89.76 g, 322.73 mmol) in 1.4- Dioxane (1.60 L) and H2O (160 mL) were added Potassium Phosphate (213.26 g, 968.19 mmol) and Pd(dppf)Ch (26.36 g, 32.27 mmol) at room temperature under nitrogen atmosphere. The resulting mixture was stirred at 90 °C for 6 h under nitrogen atmosphere. The solvents were concentrated under reduced pressure. The resulting mixture was triturated with water/ethyl acetate (1/1). The solids were collected by filtration and dried under vacuum to afford a 1:1 mixture of methyl (R)-4-amino-3-methyl-l,3-dihydrofuro[3,4- c][l,7]naphthyridine-8-caiboxylate and methyl (S)-4-amino-3-methyl-l,3-dihydrofuro[3,4- c][l,7]naphthyridine-8-carboxylate (77.20 g, 91% yield) as a brown solid. MS ESI calculated for C13H13N3O3 [M+H]⁺, 260.10; found, 260.05. 'H NMR (400 MHz, DMSO) 5 8.90 (s, 1H), 8.16 (s, 1H), 7.15 (s, 2H), 5.63 - 5.22 (m, 3H), 3.88 (s, 3H), 1.42 (d, J = 6.2 Hz, 3H).

Step-2:

[0805] To a stirred solution of a 1:1 mixture of methyl (R)-4-amino-3-methyl-l,3- dihydrofuro[3,4-c][l,7]naphthyridine-8-carboxylate and methyl (S)-4-amino-3-methyl-l,3- dihydrofuro[3,4-c][l,7]naphthyridine-8-carboxylate (77.20 g, 296.99 mmol) in HOAc (770 mL) were added PtC>2 (10.50 g, 44.04 mmol) at room temperature. The mixture was placed under hydrogen atmosphere with a balloon (1 atm.). The reaction mixture was degassed via vacuum evacuation, then backfilled with hydrogen, and this process was repeated three times. The resulting mixture was stirred at room temperature for 60 hours under hydrogen atmosphere. The mixture was filtered through a Celite pad. The filtrate was collected and concentrated under vacuum to afford to afford methyl 4-amino-3-methyl-l,3,6,7,8,9- hexahydrofuro[3,4-c][l,7]naphthyridine-8-carboxylate (70.50 g, crude) as a brown semisolid. MS ESI calculated for C13H17N3O3 [M+H]⁺, 264.13; found, 264.00.

Step-3:

[0806] To a stirred solution of methyl 4-amino-3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4- c][l,7]naphthyridine-8-carboxylate (70.50 g, 265.86 mmol) in 1,4-dioxane (700 mL) and H2O (70 mL) were added NaHCO₃ (223.34 g, 2.66 mol) and Boc₂O (116.05 g, 531.72 mmol) at 0 °C under nitrogen atmosphere. The mixture was stirred at room temperature for 16 h. The reaction mixture was diluted by brine and extracted with EtOAc. The combined organic layers were dried over anhydrous sodium sulfate, filtered and concentrated under reduced pressure. The residue was purified by flash column chromatography with 0-90% EtOAc in petroleum ether to afford a 1:4:4: 1 mixture of 7-(tert-butyl) 8-methyl (3R,8S)-4-amino-3- methyl-3,6,8,9-tetrahydrofuro[3,4-c][l,7]naphthyridine-7,8(lH)-dicarboxylate and 7-(tert- butyl) 8-methyl (3S,8S)-4-amino-3-methyl-3,6,8,9-tetrahydrofuro[3,4-c] [1 ,7]naphthyridine- 7,8(lH)-dicarboxylate and 7-(tert-butyl) 8-methyl (3R, 8R)-4-amino-3-methyl-3, 6,8,9- tetrahydrofuro[3,4-c][l,7]naphthyridine-7,8(lH)-dicarboxylate and 7-(tert-butyl) 8-methyl (3S,8R)-4-amino-3-methyl-3,6,8,9-tetrahydrofuro[3,4-c][l,7]naphthyridine-7,8(lH)- dicarboxylate (21.50 g, 20% yield over two steps) as a white solid. MS ESI calculated for C18H25N3O5 [M+H]⁺, 364.18; found, 364.15.

Step-4:

[0807] A 1 :4:4: 1 mixture of 7-(tert-butyl) 8-methyl (3R, 8S)-4-amino-3-methyl-3, 6,8,9- tetrahydrofuro[3,4-c][l,7]naphthyridine-7,8(lH)-dicarboxylate and 7-(tert-butyl) 8-methyl (3S,8S)-4-amino-3-methyl-3,6,8,9-tetrahydrofuro[3,4-c][l,7]naphthyridine-7,8(lH)- dicarboxylate and 7-(tert-butyl) 8-methyl (3R, 8R)-4-amino-3-methyl-3, 6,8,9- tetrahydrofuro[3,4-c][l,7]naphthyridine-7,8(lH)-dicarboxylate and 7-(tert-butyl) 8-methyl

(3S,8R)-4-amino-3-methyl-3,6,8,9-tetrahydrofuro[3,4-c][l,7]naphthyridine-7,8(lH)- dicarboxylate (21.50 g, 59.23 mmol) was separated by prep-chiral HPLC with the following conditions: [Column: NB_ASA CHIRALPAK IE, 5*25 cm, 10 pm; Mobile Phase A: CO2, Mobile Phase B: EtOH; Flow rate: 180 mL/min; Gradient (B%): isocratic 40% B; Column

Temperature(°C): 35; Wave Length: 220 nm; RTl(min): 4.9; RT2(min): 5.6; RT3(min): 6.4;

RT4 (min): 9. Sample Solvent: MEOH] to afford rel-7-(tert-butyl) 8-methyl (3R,8R)-4- amino-3-methyl-3,6,8,9-tetrahydrofuro[3,4-c][l,7]naphthyridine-7,8(lH)-dicarboxylate isomer 2 (1.8 g, 8%) as a white solid with retention time at 4.9 minute. MS ESI calculated for C18H25N3O5 [M+H]⁺, 364.18; found, 364.05. [0808] The chiral resolution also afforded rel-7-(tert-butyl) 8-methyl (3R,8R)-4-amino-3- methyl-3,6,8,9-tetrahydrofuro[3,4-c][l,7]naphthyridine-7,8(lH)-dicarboxylate isomer 4 (4.1 g, 19%) as a white solid with retention time at 5.6 minute. MS ESI calculated for C18H25N3O5 [M+H]⁺, 364.18; found, 364.05.

[0809] The chiral resolution also afforded rel-7-(tert-butyl) 8-methyl (3R,8R)-4-amino-3- methyl-3,6,8,9-tetrahydrofuro[3,4-c][l,7]naphthyridine-7,8(lH)-dicarboxylate isomer 1 (7.1 g, 33%) as a white solid with the third peak with retention time at 6.4 minute. MS ESI calculated for C18H25N3O5 [M+H]⁺, 364.18; found, 364.05.

[0810] The chiral resolution also afforded rel-7-(tert-butyl) 8-methyl (3R,8R)-4-amino-3- methyl-3,6,8,9-tetrahydrofuro[3,4-c][l,7]naphthyridine-7,8(lH)-dicarboxylate isomer 3 (2.1 g, 10%) as a white solid with retention time at 9 minute. MS ESI calculated for C18H25N3O5 [M+H]⁺, 364.18; found, 364.05. MS ESI calculated for C18H25N3O5 [M+H]⁺, 364.18; found, 364.05.

Step-5:

[0811] To a stirred solution of rel-7-(tert-butyl) 8-methyl (3R,8R)-4-amino-3-methyl- 3,6,8,9-tetrahydrofuro[3,4-c][l,7]naphthyridine-7,8(lH)-dicarboxylate isomer 1 (300 mg, 0.82 mmol) in DCE (5 mL) were added Trimethyltin hydroxide (597 mg, 3.30 mmol) at room temperature. The resulting mixture was stirred at 80 °C overnight. The mixture was concentrated under vacuum. The residue was purified by reversed-phase flash column chromatography with 10 - 50% MeCN in Water (0.1% FA) to afford rel-(3R,8R)-4-amino-7- (tert-butoxycarbonyl)-3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4-c][l,7]naphthyridine-8- carboxylic acid isomer 1 (CA6 isomer 1) (300 mg, 100%) as a white solid. MS ESI calculated for C17H23N3O5 [M+H]⁺, 350.16; found, 350.10. Absolute stereochemistry was not determined.

Step-6:

[0812] To a stirred solution of rel-7-(tert-butyl) 8-methyl (3R,8R)-4-amino-3-methyl- 3,6,8,9-tetrahydrofuro[3,4-c][l,7]naphthyridine-7,8(lH)-dicarboxylate isomer 2 (200 mg, 0.55 mmol) in DCE (5 mL) were added Trimethyltin hydroxide (398 mg, 2.20 mmol) at room temperature. The resulting mixture was stirred at 80 °C overnight. The mixture was concentrated under vacuum. The residue was purified by reversed-phase flash column chromatography with 10 - 50% MeCN in Water (0.1% FA) to afford rel-(3R,8R)-4-amino-7-

(tert-butoxycarbonyl)-3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4-c][l,7]naphthyridine-8- carboxylic acid isomer 2 (CA6 isomer 2) (200 mg, 100%) as a white solid. MS ESI calculated for C17H23N3O5 [M+H]⁺, 350.16; found, 350.10. Absolute stereochemistry was not determined.

Step-7:

[0813] To a stirred solution of rel-7-(tert-butyl) 8-methyl (3R,8R)-4-amino-3-methyl- 3,6,8,9-tetrahydrofuro[3,4-c][l,7]naphthyridine-7,8(lH)-dicarboxylate isomer 3 (2.10 g, 5.78 mmol) in DCE (40 mL) were added Trimethyltin hydroxide (4.18 g, 23.11 mmol) at room temperature. The resulting mixture was stirred at 80 °C overnight. The solvents were removed under vacuum and purified directly. The residue was purified by reversed-phase flash column chromatography with 10-50% MeCN in Water (0.1% FA) to afford rel- (3R,8R)-4-amino-7-(tert-butoxycarbonyl)-3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4- c][l,7]naphthyridine-8-carboxylic acid isomer 3 (CA6 isomer 3) (1.50 g, 74%) as a yellow solid. MS ESI calculated for C17H23N3O5 [M+H]⁺, 350.16; found, 350.10. 'H NMR (400 MHz, DMSO-de) 8 12.75 (s, 1H), 5.93 - 5.71 (m, 2H), 5.26 - 5.16 (m, 1H), 5.04 - 4.75 (m, 3H), 4.48 - 4.34 (m, 1H), 4.29 - 3.99 (m, 1H), 2.93 - 2.76 (m, 2H), 1.43 (d, J= 15.0 Hz, 9H), 1.32 (d, 7= 6.2 Hz, 3H). [0814] Absolute stereochemistry of CA6 isomer 3 was determined by single crystal X-ray crystallography of Example 38 prepared using CA6 isomer 3. Accordingly, CA6 isomer 3 is represented by the formula:

Step-8:

[0815] To a stirred solution of rel-7-(tert-butyl) 8-methyl (3R,8R)-4-amino-3-methyl- 3,6,8,9-tetrahydrofuro[3,4-c][l,7]naphthyridine-7,8(lH)-dicarboxylate isomer 4 (300 mg, 0.82 mmol) in DCE (3 mL) were added Trimethyltin hydroxide (597 mg, 3.30 mmol) at room temperature. The resulting mixture was stirred at 80 °C overnight. The residue was purified by reversed-phase flash column chromatography with 10-50% MeCN in Water (0.1% FA) to afford rel-(3R, 8R)-4-amino-7-(tert-butoxycarbonyl)-3-methyl-l, 3, 6,7,8, 9-hexahydrofuro[3, 4- c][l,7]naphthyridine-8-carboxylic acid isomer 4 (CA6 isomer 4) (300 mg, 100%) as a white solid. MS ESI calculated for C17H23N3O5 [M+H]⁺, 350.16; found, 350.10. Absolute stereochemistry was not determined.

Intermediate CA7: 4-((tert-butoxycarbonyl)amino)-3-methyl-3,6,8,9-tetrahydro-lH- furo [3 ,4-d]pyrano [3,4-b]pyridine-8-carboxylic acid

^CA7 ; and,

Intermediate CA8: 4-((tert-butoxycarbonyl)amino)-l-methyl-3,6,8,9-tetrahydro-lH- fiiro [3 ,4-d]pyrano [3,4-b]pyridine-8-carboxylic acid

CA8

Step-1:

[0816] To a stirred mixture of KOH (86.45 g, 1540.85 mmol) in DMSO (750 mL) was added but-3-yn-2-ol (36 g, 513.62 mmol) at 10 °C under nitrogen atmosphere. The resulting mixture was stirred at 10 °C for 1 h under nitrogen atmosphere. Then 3-bromoprop-l-yne (61.10 g, 513.62 mmol) was added dropwise over 20 min at 10 °C. The resulting mixture was stirred at room temperature for 16 h. The resulting mixture was filtered, and the filter cake was washed with DMSO. The filtrate was diluted with water and acidified with HC1 (aq.) to pH 4. The mixture was extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous Na2SO4. After filtration, the filtrate was concentrated under reduced pressure to afford 3-(prop-2-yn-l-yloxy)but-l-yne (23.00 g, 40%) as a brown liquid. 'H NMR (400 MHz, CDCl₃-d) 84.46 - 4.40 (m, 1H), 4.39 - 4.23 (m, 2H), 2.46 (d, J = 2.0 Hz, 1H), 2.45 (t, J = 2.4 Hz, 1H), 1.48 (d, J= 6.8 Hz, 3H).

Step-2:

[0817] To a stirred mixture of 3-(prop-2-yn-l-yloxy)but-l-yne (13.50 g, 124.84 mmol) in DCM (540 mL) were added AgNO₃ (46.65 g, 274.64 mmol) and NBS (48.88 g, 274.64 mmol) at 0 °C under nitrogen atmosphere. The resulting mixture was stirred at room temperature for 16 h under nitrogen atmosphere. The resulting mixture was filtered, and the filter cake was washed with DCM. The filtrate was concentrated under reduced pressure. The residue was dissolved in diethyl ether, and the solids were filtered off, the filter cake was washed with diethyl ether. The filtrate was combined and concentrated under reduced pressure to afford l-bromo-3-((3-bromoprop-2-yn-l-yl)oxy)but-l-yne (21.7 g, 61%) as a brown oil. NMR (400 MHz, CDCI3-4Z) 84.46 - 4.39 (m, 1H), 4.39 - 4.25 (m, 2H), 1.48 (d, J = 6.8 Hz, 3H).

[0818] To a stirred solution of ethyl carbonocyanidate (16.17 g, 163.20 mmol) in DCE (400 mL) were added Cp*RuCl(cod) (1.55 g, 4.08 mmol) and l-bromo-3-((3-bromoprop-2-yn-l- yl)oxy)but-l-yne (21.70 g, 81.60 mmol) at 0 °C under nitrogen atmosphere. The resulting mixture was stirred at room temperature for 16 h under nitrogen atmosphere. The resulting mixture was diluted with water and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous NaiSCX After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-20% EtOAc in petroleum ether to afford a 1:8 mixture of ethyl 4,7-dibromo-3-methyl-l,3-dihydrofuro[3,4-c]pyridine-6-carboxylate and ethyl 4,7- dibromo-l-methyl-l,3-dihydrofuro[3,4-c]pyridine-6-carboxylate (5.2 g, 17%) as a yellow oil. MS ESI calculated for CnHnBnNCh [M+H]⁺, 363.91, 365.91, 367.91; found, 363.90, 365.90, 367.90. 'H NMR (400 MHz, DMSO-t/₆) 8 5.54 - 5.41 (m, 1H), 5.24 - 5.12 (m, 1H), 5.10 - 4.98 (m, 1H), 4.40 (q, J= 7.2 Hz, 2H), 1.54 - 1.47 (m, 3H), 1.34 (t, J = 7.2 Hz, 3H).

Step-4:

[0819] To a stirred solution of 1:8 mixture of ethyl 4,7-dibromo-3-methyl-l,3- dihydrofuro[3,4-c]pyridine-6-carboxylate and ethyl 4,7-dibromo-l-methyl-l,3- dihydrofuro[3,4-c]pyridine-6-carboxylate (20.00 g, 54.79 mmol) and PMBNH2 (7.52 g, 54.79 mmol) in 1,4-dioxane (200 mL) were added CS2CO3 (17.85 g, 54.79 mmol), XantPhos Pd G3 (2.84 g, 2.74 mmol) and XantPhos (1.59 g, 2.74 mmol) at room temperature under nitrogen atmosphere. The resulting mixture was stirred at 100 °C for 16 h. The mixture was allowed to cool down to room temperature and then filtered, the filter cake was washed with ethyl acetate. The filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-13% EtOAc in petroleum ether to afford a 1:8 mixture of ethyl 7-bromo-4-((4-methoxybenzyl)amino)-3-methyl-l,3-dihydrofuro[3,4- c]pyridine-6-carboxylate and ethyl 7-bromo-4-((4-methoxybenzyl)amino)-l-methyl-l,3- dihydrofuro[3,4-c]pyridine-6-carboxylate (14.00 g, 60%) as a brown solid. MS ESI calculated for Ci₉H₂iBrN₂O₄ [M+H]⁺, 421.07, 423.07; found, 421.05, 423.05.

Step-5:

[0820] To a stirred solution of 1:8 mixture of ethyl 7-bromo-4-((4-methoxybenzyl)amino)- 3-methyl-l,3-dihydrofuro[3,4-c]pyridine-6-carboxylate and ethyl 7-bromo-4-((4- methoxybenzyl)amino)- 1 -methyl- 1 ,3-dihydrofuro[3,4-c]pyridine-6-carboxylate (26.00 g, 61.72 mmol) and allyltributylstannane (24.52 g, 74.06 mmol) in DMF (300 mL) was added Pd(PPh3)4 (3.57 g, 3.09 mmol) at room temperature. The resulting mixture was stirred at 100 °C for 16 h under nitrogen atmosphere. The mixture was allowed to cool down to room temperature and diluted with water. The resulting mixture was extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous Na₂SO4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-50% EtOAc in petroleum ether to afford a 1:8 mixture of ethyl 7-allyl-4-((4-methoxybenzyl)amino)-3-methyl-l,3-dihydrofuro[3,4- c]pyridine-6-carboxylate and ethyl 7-allyl-4-((4-methoxybenzyl)amino)-l -methyl- 1,3- dihydrofuro[3,4-c]pyridine-6-carboxylate (21.0 g, 89%) as a yellow oil. MS ESI calculated for C₂₂H₂₆N₂O₄ [M+H]⁺, 383.19; found, 383.20.

Step-6:

[0821] To a stirred solution of 1:8 mixture of ethyl 7-allyl-4-((4-methoxybenzyl)amino)-3- methyl-l,3-dihydrofuro[3,4-c]pyridine-6-carboxylate and ethyl 7-allyl-4-((4- methoxybenzyl)amino)- 1 -methyl- 1 ,3-dihydrofuro[3,4-c]pyridine-6-carboxylate (21.00 g, 54.91 mmol) in THF (200 mL), t-BuOH (200 mL) and H₂O (40 mL) were added NMO (7.72 g, 65.89 mmol) and OsCL (698 mg, 2.74 mmol) at room temperature. The resulting mixture was stirred at room temperature for 4 h. The reaction was quenched by the addition of sodium hyposulfite (sat.) at room temperature. The resulting mixture was extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous Na₂SO4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0 ~ 10% MeOH in DCM to afford a 1:8 mixture of tert-butyl 8-(hydroxymethyl)-4-((4-methoxybenzyl)amino)-3-methyl-l, 3,8,9- tetrahydro-6H-furo[3,4-d]pyrano[3,4-b]pyridin-6-one and 8-(hydroxymethyl)-4-((4- methoxybenzyl)amino)-l-methyl-l,3,8,9-tetrahydro-6H-furo[3,4-d]pyrano[3,4-b]pyridin-6- one (20.0 g, 87%) as a brown oil. MS ESI calculated for C20H22N2O5 [M+H]⁺, 371.15; found, 371.15.

Step-7:

[0822] To a stirred solution of 1:8 mixture of tert-butyl 8-(hydroxymethyl)-4-((4- methoxybenzyl)amino)-3-methyl-l,3,8,9-tetrahydro-6H-furo[3,4-d]pyrano[3,4-b]pyridin-6- one and 8-(hydroxymethyl)-4-((4-methoxybenzyl)amino)- 1 -methyl- 1 ,3,8,9-tetrahydro-6H- furo[3,4-d]pyrano[3,4-b]pyridin-6-one (20.00 g, 53.99 mmol) and imidazole (7.35 g, 107.99 mmol) in DCM (200 mL) was added TBDPSC1 (17.81 g, 64.79 mmol) at room temperature under nitrogen atmosphere. The resulting mixture was stirred at room temperature for 2 h. The reaction mixture was washed with water. The organic layer was dried over anhydrous Na2SC>4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-75% EtOAc in petroleum ether to afford a 1:8 mixture of 8-(((tert-butyldiphenylsilyl)oxy)methyl)-4-((4- methoxybenzyl)amino)-3-methyl-l,3,8,9-tetrahydro-6H-furo[3,4-d]pyrano[3,4-b]pyridin-6- one and 8-(((tert-butyldiphenylsilyl)oxy)methyl)-4-((4-methoxybenzyl)amino)- 1 -methyl- l,3,8,9-tetrahydro-6H-furo[3,4-d]pyrano[3,4-b]pyridin-6-one (28.0 g, 85%) as a yellow oil. MS ESI calculated for C₃6H4oN₂0₅Si [M+H]⁺, 609.27; found, 609.40.

Step-8:

[0823] To a stirred solution of 1:8 mixture of 8-(((tert-butyldiphenylsilyl)oxy)methyl)-4- ((4-methoxybenzyl)amino)-3-methyl-l,3,8,9-tetrahydro-6H-furo[3,4-d]pyrano[3,4-b]pyridin- 6-one and 8-(((tert-butyldiphenylsilyl)oxy)methyl)-4-((4-methoxybenzyl)amino)- 1 -methyl- l,3,8,9-tetrahydro-6H-furo[3,4-d]pyrano[3,4-b]pyridin-6-one (24.5 g, 40.24 mmol) in THF (250 mL) were added a solution of CaCh (13.40 g, 120.72 mmol) in EtOH (250 mL) and NaBH4 (4.57 g, 120.72 mmol) at 0 °C under nitrogen atmosphere. The resulting mixture was stirred at room temperature for 2 h. The reaction was quenched by the addition of water at room temperature and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous NaiSC . After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0 ~ 40% EtOAc in petroleum ether to afford a 1:8 mixture of 1- ((tert-butyldiphenylsilyl)oxy)-3-(6-(hydroxymethyl)-4-((4-methoxybenzyl)amino)-3-methyl- l,3-dihydrofuro[3,4-c]pyridin-7-yl)propan-2-ol and l-((tert-butyldiphenylsilyl)oxy)-3-(6- (hydroxymethyl)-4-((4-methoxybenzyl)amino)-l-methyl-l,3-dihydrofuro[3,4-c]pyridin-7- yl)propan-2-ol (22.00 g, 89%) as a yellow oil. MS ESI calculated for C36H44N2OsSi [M+H]⁺, 613.30; found, 613.40.

Step-9:

[0824] A solution of 1:8 mixture of l-((tert-butyldiphenylsilyl)oxy)-3-(6-(hydroxymethyl)- 4-((4-methoxybenzyl)amino)-3-methyl- 1 ,3-dihydrofuro[3,4-c]pyridin-7-yl)propan-2-ol and 1 -((tert-butyldiphenylsilyl)oxy)-3-(6-(hydroxymethyl)-4-((4-methoxybenzyl)amino)- 1 - methyl-l,3-dihydrofuro[3,4-c]pyridin-7-yl)propan-2-ol (22.00 g, 35.90 mmol) and 2- (tributyl-A,⁵-phosphaneylidene)acetonitrile (CAS No. 157141-27-0) (17.33 g, 71.80 mmol) in toluene (250 mL) was stirred at 110 °C for 2 h under nitrogen atmosphere. The mixture was allowed to cool down to room temperature and concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-24% EtOAc in petroleum ether to afford a 1:8 mixture of 8-(((tert-butyldiphenylsilyl)oxy)methyl)-N-(4- methoxybenzyl)-3-methyl-3,6,8,9-tetrahydro-lH-furo[3,4-d]pyrano[3,4-b]pyridin-4-amine and 8-(((tert-butyldiphenylsilyl)oxy)methyl)-N-(4-methoxybenzyl)- 1 -methyl-3, 6, 8, 9- tetrahydro-lH-furo[3,4-d]pyrano[3,4-b]pyridin-4-amine (21.00 g, 98%) as a yellow oil. MS ESI calculated for C36H₄2N₂O4Si [M+H]⁺, 595.29; found, 595.40.

Step- 10:

[0825] To a stirred solution of 1:8 mixture of 8-(((tert-butyldiphenylsilyl)oxy)methyl)-N- (4-methoxybenzyl)-3-methyl-3,6,8,9-tetrahydro-lH-furo[3,4-d]pyrano[3,4-b]pyridin-4-amine and 8-(((tert-butyldiphenylsilyl)oxy)methyl)-N-(4-methoxybenzyl)- 1 -methyl-3, 6, 8, 9- tetrahydro-lH-furo[3,4-d]pyrano[3,4-b]pyridin-4-amine (15.9 g, 26.73 mmol) in TFA (160 mL) was added TfOH (16 mL) at room temperature. The resulting mixture was stirred at room temperature for 16 h. The resulting mixture was concentrated under reduced pressure. The residue was dissolved in methanol (160 mL), then K2CO3 (11.08 g, 80.19 mmol) was added at room temperature. The resulting mixture was stirred at 70 °C for additional 2 h. The mixture was allowed to cool down to room temperature and concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-20% MeOH in DCM to afford a 1:8 mixture of (4-amino-3-methyl-3,6,8,9-tetrahydro-lH-furo[3,4- d]pyrano[3,4-b]pyridin-8-yl)methanol and (4-amino-l-methyl-3,6,8,9-tetrahydro-lH- furo[3,4-d]pyrano[3,4-b]pyridin-8-yl)methanol (5.9 g, 93%) as a white solid. MS ESI calculated for C12H16N2O3 [M+H]⁺, 237.12; found, 237.15.

Step-11:

[0826] To a stirred solution of 1:8 mixture of (4-amino-3-methyl-3,6,8,9-tetrahydro-lH- furo[3,4-d]pyrano[3,4-b]pyridin-8-yl)methanol and (4-amino- 1 -methyl-3, 6, 8, 9-tetrahydro- lH-furo[3,4-d]pyrano[3,4-b]pyridin-8-yl)methanol (1.1 g, 4.65 mmol) and TEA (2.36 g, 23.28 mmol) in THF (20 mL) were added DMAP (0.11 g, 0.93 mmol) and BoczO (3.35 g, 15.36 mmol) at room temperature under nitrogen atmosphere. The resulting mixture was stirred at room temperature for 2 h. The resulting mixture was diluted with water and extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SO4. After filtration, the filtrate was concentrated under reduced pressure. The residue was dissolved in methanol (48 mL), this was followed by the addition of NaOH (25%, aq.) (14 mL) dropwise at room temperature. The mixture was stirred at room temperature for additional 3 h. The resulting mixture was diluted with water and extracted with DCM. The combined organic layers were washed with brine, dried over anhydrous Na2SC>4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-80% EtOAc in petroleum ether to afford a 1:8 mixture of tert-butyl (8-(hydroxymethyl)-3-methyl-3,6,8,9-tetrahydro- lH-furo[3,4-d]pyrano[3,4-b]pyridin-4-yl)carbamate and tert-butyl (8-(hydroxymethyl)-l- methyl-3,6,8,9-tetrahydro-lH-furo[3,4-d]pyrano[3,4-b]pyridin-4-yl)carbamate (1.04 g, 66%) as a white solid. MS ESI calculated for C17H24N2O5 [M+H]⁺, 337.17; found, 337.15.

Step- 12:

[0827] To a stirred solution of 1:8 mixture of tert-butyl (8-(hydroxymethyl)-3-methyl-

3.6.8.9-tetrahydro-lH-furo[3,4-d]pyrano[3,4-b]pyridin-4-yl)carbamate and tert-butyl (8- (hydroxymethyl)-l-methyl-3,6,8,9-tetrahydro-lH-furo[3,4-d]pyrano[3,4-b]pyridin-4- yl)carbamate (900 mg, 2.67 mmol) in MeCN (6 mL) and H2O (3 mL) was added TEMPO (167 mg, 1.07 mmol) and phenyl-13-iodanediyl diacetate (862 mg, 2.67 mmol) at 0 °C. The resulting mixture was stirred at room temperature for 16 h. The mixture was purified directly by reverse phase column chromatography with 5% to 20% MeCN in Water (10 mmol/L NH4HCO3) to afford a 1:8 mixture of tert-butyl 4-((tert-butoxycarbonyl)amino)-3-methyl-

3.6.8.9-tetrahydro-lH-furo[3,4-d]pyrano[3,4-b]pyridine-8-carboxylic acid (CA7) and tertbutyl 4-((tert-butoxycarbonyl)amino)-l-methyl-3,6,8,9-tetrahydro-lH-furo[3,4-d]pyrano[3,4- b]pyridine-8-carboxylic acid (CA8) (540 mg, 58%) as a white solid. MS ESI calculated for C17H22N2O6 [M+H]⁺, 351.15; found, 351.10.

Intermediate CA11: (R)-4-acetamido-l,3,6,7,8,9-hexahydrofuro[3,4-c]quinoline-8- carboxylic acid

[0828] To a stirred solution of methyl (R)-4-acetamido-l,3,6,7,8,9-hexahydrofuro[3,4- c]quinoline-8-carboxylate (1.0 g, 3.44 mmol) in DCE (10 mL) was added trimethyltin(IV) hydroxide (2.49 g, 13.77 mmol) at room temperature. The resulting mixture was stirred at 80 °C for 16 h. The resulting mixture was concentrated under vacuum. The residue was acidified with HC1 (aq., IN) to pH 1. The mixture was purified by reverse phase flash column chromatography with a 48 g Cl 8 column with 5-20% acetonitrile in water to afford (R)-4- acetamido-l,3,6,7,8,9-hexahydrofuro[3,4-c]quinoline-8-carboxylic acid (CA11) (680 mg, 71%) as a white solid. MS ESI calculated for C14H16N2O4 [M+H]⁺, 277.11 ; found, 277.10. ’H NMR (400 MHz, DMSO-Jg) 8 11.20 (s, 1H), 5.23 - 4.99 (m, 4H), 3.04 - 2.90 (m, 2H), 2.90 - 2.63 (m, 3H), 2.16 - 2.15 (m, 1H), 2.08 (s, 3H), 1.87 - 1.82 (m, 1H).

[0829] The absolute stereochemistry of CA11 was determined by crystallography of Example 8 prepared using CAI isomer 2, where CAI isomer 2 was prepared from methyl (R)-4-acetamido-l,3,6,7,8,9-hexahydrofuro[3,4-c]quinoline-8-carboxylate.

Intermediate CA12: 1:1: 1:1 mixture of (3R,8S)-4-((tert-butoxycarbonyl)(4- methoxybenzyl)amino)-3-methyl-3,6,8,9-tetrahydro-lH-furo[3,4-d]pyrano[3,4- b]pyridine-8-carboxylic acid and (3R,8R)-4-((tert-butoxycarbonyl)(4- methoxybenzyl)amino)-3-methyl-3,6,8,9-tetrahydro-lH-furo[3,4-d]pyrano[3,4- b]pyridine-8-carboxylic acid and (3S,8S)-4-((tert-butoxycarbonyl)(4- methoxybenzyl)amino)-3-methyl-3,6,8,9-tetrahydro-lH-furo[3,4-d]pyrano[3,4- b]pyridine-8-carboxylic acid and (3S,8R)-4-((tert-butoxycarbonyl)(4- methoxybenzyl)amino)-3-methyl-3,6,8,9-tetrahydro-lH-furo[3,4-d]pyrano[3,4- b]pyridine-8-carboxylic acid

[0830] To a stirred solution of methyl 5-bromo-2-chloroisonicotinate (38.00 g, 151.71 mmol) and tributyl(l-ethoxyvinyl)stannane (54.79 g, 151.71 mmol) in 1,4-dioxane (500 mL) was added Pd(PPh3)2Ch (5.32 g, 7.59 mmol) at room temperature under nitrogen atmosphere. The resulting mixture was stirred at 80 °C for 16 h under nitrogen atmosphere. The mixture was allowed to cool down to room temperature and concentrated under reduced pressure. The residue was dissolved in THF (600 mL), and then HC1 (aq., 10%) (600 mL) was added. The mixture was stirred at room temperature for 16 h. The resulting mixture was extracted with ethyl acetate. The combined organic layers were washed with NaHCCh (aq.), dried over anhydrous NaiSCL. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-16% EA in PE to afford methyl 5-acetyl-2-chloroisonicotinate (14.00 g, 20%) as a white solid. MS ESI calculated for C₉H₈C1NO₃ [M+H]⁺, 214.02; found, 214.00.

Step-2:

[0831] To a stirred solution of methyl 5-acetyl-2-chloroisonicotinate (50.00 g, 234.06 mmol) in THF (100 mL) was added L-selectride (1.0M/L in THF, 702 mL) dropwise at - 78 °C under nitrogen atmosphere. The resulting mixture was stirred at room temperature for 16 h under nitrogen atmosphere. The reaction was quenched with MeOH at room temperature and concentrated under vacuum. The residue was purified by silica gel column chromatography, eluted with 0-21% MeOH in DCM to afford a 1: 1 mixture of (R)-l-(6- chloro-4-(hydroxymethyl)pyridin-3-yl)ethan-l-ol and (S)-l-(6-chloro-4- (hydroxymethyl)pyridin-3-yl)ethan-l-ol (43.00 g, 97%) as a yellow oil. MS ESI calculated for C₈HI₀C1NO₂ [M+H]⁺, 188.04; found, 188.15.

Step-3:

[0832] A solution of 1:1 mixture of (R)-l-(6-chloro-4-(hydroxymethyl)pyridin-3-yl)ethan- l-ol and (S)-l-(6-chloro-4-(hydroxymethyl)pyridin-3-yl)ethan-l-ol (43.00 g, 229.19 mmol) and 2-(tributyl-X⁵-phosphaneylidene)acetonitrile (CAS No. 157141-27-0) (82.97 g, 343.78 mmol) in toluene (500 mL) was stirred at 110 °C for 16 h under nitrogen atmosphere. The mixture was allowed to cool down to room temperature and concentrated under vacuum. The residue was purified by silica gel column chromatography, eluted with 0-9% EtOAc in PE to afford a 1:1 mixture of (R)-6-chloro-3-methyl-l,3-dihydrofuro[3,4-c]pyridine and (S)-6- chloro-3-methyl-l,3-dihydrofuro[3,4-c]pyridine (32.00 g, 82%) as a green liquid. MS ESI calculated for C₈H₈C1NO [M+H]⁺, 170.03; found, 170.00.

Step-4:

[0833] To a stirred solution of 1: 1 mixture of (R)-6-chloro-3-methyl-l,3-dihydrofuro[3,4- c]pyridine and (S)-6-chloro-3-methyl-l,3-dihydrofuro[3,4-c]pyridine (30.00 g, 176.88 mmol) in DCM (600 mL) was added m-CPBA (76.30 g, 442.19 mmol) in portions at 0 °C. The resulting mixture was stirred at room temperature for 16 h. The resulting mixture was filtered, and the filter cake was washed with DCM. The filtrate was washed with NazSzOs (aq.) and NaHCCh (aq.). The organic layer was dried over anhydrous NazSCti. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-11% MeOH in DCM to afford a 1:1 mixture of (R)-6- chloro-3-methyl-l,3-dihydrofuro[3,4-c]pyridine 5-oxide and (S)-6-chloro-3-methyl-l,3- dihydrofuro[3,4-c]pyridine 5-oxide (17.00 g, 51%) as a white solid. MS ESI calculated for C₈H₈C1NO₂ [M+H]⁺, 186.02; found, 186.10.

Step-5:

[0834] A mixture of a 1:1 mixture of (R)-6-chloro-3-methyl-l,3-dihydrofuro[3,4-c]pyridine 5-oxide and (S)-6-chloro-3-methyl-l,3-dihydrofuro[3,4-c]pyridine 5-oxide (17.00 g, 91.59 mmol) and POBn (31.51 g, 109.91 mmol) in 1,2-DCE (350 mL) was stirred at 60 °C for 3 h under nitrogen atmosphere. The mixture was allowed to cool down to room temperature and quenched with NaHCCh (aq.) at 0 °C. The resulting mixture was extracted with DCM. The combined organic layers were washed with brine, dried over anhydrous Na2SC>4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-26% EtOAc in PE to afford a 1:1 mixture of (R)-4-bromo-6-chloro-3-methyl- 1 ,3-dihydrofuro[3,4-c]pyridine and (S)-4-bromo-6-chloro-3- methyl-l,3-dihydrofuro[3,4-c]pyridine (7.30 g, 32%) as a brown oil. MS ESI calculated for C₈H₇BrClNO [M+H]⁺, 247.94, 249.94; found, 247.85, 249.85.

Step-6:

[0835] To a stirred solution of 1:1 mixture of (R)-4-bromo-6-chloro-3-methyl-l,3- dihydrofuro[3,4-c]pyridine and (S)-4-bromo-6-chloro-3-methyl- 1 ,3-dihydrofuro[3,4- c]pyridine (7.30 g, 29.37 mmol) and PMBNH2 (3.70 g, 29.37 mmol) in dioxane (140 mL) were added CS2CO3 (17.56 g, 59.74 mmol), XantPhos (0.78 g, 1.47 mmol) and XantPhos Pd G3 (1.28 g, 1.47 mmol) at room temperature under nitrogen atmosphere. The resulting mixture was stirred at 90 °C for 16 h under nitrogen atmosphere. The mixture was allowed to cool down to room temperature and diluted with water. The resulting mixture was extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SC>4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-30% ethyl acetate in petroleum ether to afford a 1:1 mixture of (R)-6-chloro-N-(4-methoxybenzyl)-3-methyl-l,3- dihydrofuro[3,4-c]pyridin-4-amine and (S)-6-chloro-N-(4-methoxybenzyl)-3-methyl- 1,3- dihydrofuro[3,4-c]pyridin-4-amine (2.50 g, 27%) as a yellow solid. MS ESI calculated for C16H17CIN2O2 [M+H]⁺, 305.10; found, 305.10. Step-7:

[0836] To a stirred solution of 1:1 mixture of (R)-6-chloro-N-(4-methoxybenzyl)-3-methyl- l,3-dihydrofuro[3,4-c]pyridin-4-amine and (S)-6-chloro-N-(4-methoxybenzyl)-3-methyl-l,3- dihydrofuro[3,4-c]pyridin-4-amine (1.90 g, 6.23 mmol), oxalic acid (1.57 g, 12.46 mmol) and AC2O (1.27 g, 12.46 mmol) in DMF (20 mL) were added Pd(OAc)2 (140 mg, 0.62 mmol), XantPhos (720 mg, 1.24 mmol) and DIEA (1.61 g, 12.46 mmol) at room temperature under nitrogen atmosphere. The resulting mixture was stirred at 100 °C for 16 h under nitrogen atmosphere. The mixture was allowed to cool down to room temperature. To the above mixture were added K2CO3 (6.03 g, 43.63 mmol) and Mel (4.42 g, 31.17 mmol) at room temperature. The resulting mixture was stirred at room temperature for 16 h. The resulting mixture was diluted with water and extracted with EA. The combined organic layers were washed with brine, dried over anhydrous Na2SC>4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-50% ethyl acetate in petroleum ether to afford a 1:1 mixture of methyl (R)-4-((4-methoxybenzyl)amino)-3-methyl-l ,3-dihydrofuro[3,4-c]pyridine-6- carboxylate and methyl (S)-4-((4-methoxybenzyl)amino)-3-methyl-l,3-dihydrofuro[3,4- c]pyridine-6-carboxylate (900 mg, 44%) as a brown oil. MS ESI calculated for C18H20N2O4 [M+H]⁺, 329.14; found, 329.10.

Step-8:

[0837] To a stirred solution of 1:1 mixture of methyl (R)-4-((4-methoxybenzyl)amino)-3- methyl-l,3-dihydrofuro[3,4-c]pyridine-6-carboxylate and methyl (S)-4-((4- methoxybenzyl)amino)-3-methyl- 1 ,3-dihydrofuro[3,4-c]pyridine-6-carboxylate (840 mg, 2.55 mmol) in MeCN (16 mL) was added NBS (455 mg, 2.55 mmol) at room temperature. The resulting mixture was stirred at room temperature for 16 h. The resulting mixture was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-30% ethyl acetate in petroleum ether to afford a 1:1 mixture of methyl (R)-7 -bromo-4-((4-methoxybenzyl)amino)-3-methyl- 1 ,3-dihydrofuro [3 ,4- c]pyridine-6-carboxylate and methyl (S)-7-bromo-4-((4-methoxybenzyl)amino)-3-methyl- l,3-dihydrofuro[3,4-c]pyridine-6-carboxylate (750 mg, 72%) as a yellow oil. MS ESI calculated for Ci8Hi₉BrN₂O4 [M+H]⁺, 407.05, 409.05; found, 407.05, 409.05.

Step-9:

[0838] To a stirred solution of a 1:1 mixture of methyl (R)-7-bromo-4-((4- methoxybenzyl)amino)-3-methyl- 1 ,3-dihydrofuro[3,4-c]pyridine-6-carboxylate and methyl (S)-7-bromo-4-((4-methoxybenzyl)amino)-3-methyl-l,3-dihydrofuro[3,4-c]pyridine-6- carboxylate (750 mg, 1.84 mmol) and tributyl(prop-2-en-l-yl)stannane (731 mg, 2.21 mmol) in DMF (8 mL) was added Pd(PPh3)4 (212 mg, 0.18 mmol) at room temperature. The resulting mixture was stirred at 100 °C for 2 h under nitrogen atmosphere. The mixture was allowed to cool down to room temperature and diluted with water. The resulting mixture was extracted with EA. The combined organic layers were washed with brine, dried over anhydrous Na2SC>4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-60% ethyl acetate in petroleum ether to afford a 1:1 mixture of methyl (R)-7-allyl-4-((4-methoxybenzyl)amino)-3- methyl-l,3-dihydrofuro[3,4-c]pyridine-6-carboxylate and methyl (S)-7-allyl-4-((4- methoxybenzyl)amino)-3-methyl- 1 ,3-dihydrofuro[3,4-c]pyridine-6-carboxylate (630 mg, 92%) as a yellow oil. MS ESI calculated for C21H24N2O4 [M+H]⁺, 369.17; found, 369.15.

Step-10: [0839] To a stirred solution of 1: 1 mixture of methyl (R)-7-allyl-4-((4- methoxybenzyl)amino)-3-methyl- 1 ,3-dihydrofuro[3,4-c]pyridine-6-carboxylate and methyl (S)-7-aUyl-4-((4-methoxybenzyl)amino)-3-methyl-l,3-dihydrofuro[3,4-c]pyridine-6- carboxylate (630 mg, 1.71 mmol) and NMO (240 mg, 2.05 mmol) in THF (5 mL) and H2O (1 mL) was added OsC>4 (43 mg, 0.17 mmol) at room temperature. The resulting mixture was stirred at room temperature for 16 h. The reaction was quenched by the addition of sat. Na2S2C>3 (aq.) at room temperature. The resulting mixture was extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SC>4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-20% methanol in dichloromethane to afford a 1:1:1:1 mixture of (3R,8S)-8-(hydroxymethyl)-4-((4-methoxybenzyl)amino)-3-methyl- 1 ,3,8,9-tetrahydro-6H-furo[3,4-d]pyrano[3,4-b]pyridin-6-one and (3R,8R)-8- (hydroxymethyl)-4-((4-methoxybenzyl)amino)-3-methyl-l,3,8,9-tetrahydro-6H-furo[3,4- d]pyrano[3,4-b]pyridin-6-one and (3S,8S)-8-(hydroxymethyl)-4-((4-methoxybenzyl)amino)- 3-methyl-l,3,8,9-tetrahydro-6H-furo[3,4-d]pyrano[3,4-b]pyridin-6-one and (3S,8R)-8- (hydroxymethyl)-4-((4-methoxybenzyl)amino)-3-methyl-l,3,8,9-tetrahydro-6H-furo[3,4- d]pyrano[3,4-b]pyridin-6-one (600 mg, 94%) as a colorless oil. MS ESI calculated for C20H22N2O5 [M+H]⁺, 371.15; found, 371.15.

Step-11:

[0840] To a stirred solution of 1 : 1 : 1 : 1 mixture of (3R,8S)-8-(hydroxymethyl)-4-((4- methoxybenzyl)amino)-3-methyl-l,3,8,9-tetrahydro-6H-furo[3,4-d]pyrano[3,4-b]pyridin-6- one, (3R,8R)-8-(hydroxymethyl)-4-((4-methoxybenzyl)amino)-3-methyl-l,3,8,9-tetrahydro- 6H-furo[3,4-d]pyrano[3,4-b]pyridin-6-one, (3S,8S)-8-(hydroxymethyl)-4-((4- methoxybenzyl)amino)-3-methyl-l,3,8,9-tetrahydro-6H-furo[3,4-d]pyrano[3,4-b]pyridin-6- one and (3S,8R)-8-(hydroxymethyl)-4-((4-methoxybenzyl)amino)-3-methyl- 1 ,3,8,9- tetrahydro-6H-furo[3,4-d]pyrano[3,4-b]pyridin-6-one (600 mg, 1.62 mmol) and imidazole (220 mg, 3.24 mmol) in DCM (6 mL) was added TBDPSC1 (489 mg, 1.78 mmol) at room temperature. The resulting mixture was stirred at room temperature for 5 h. The resulting mixture was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-50% ethyl acetate in petroleum ether to afford a 1 :1 : 1 : 1 mixture of (3R,8S)-8-(((tert-butyldiphenylsilyl)oxy)methyl)-4-((4- methoxybenzyl)amino)-3-methyl-l,3,8,9-tetrahydro-6H-furo[3,4-d]pyrano[3,4-b]pyridin-6- one, (3R,8R)-8-(((tert-butyldiphenylsilyl)oxy)methyl)-4-((4-methoxybenzyl)amino)-3- methyl-l,3,8,9-tetrahydro-6H-furo[3,4-d]pyrano[3,4-b]pyridin-6-one, (3S,8S)-8-(((tert- butyldiphenylsilyl)oxy)methyl)-4-((4-methoxybenzyl)amino)-3-methyl-l,3,8,9-tetrahydro- 6H-furo[3,4-d]pyrano[3,4-b]pyridin-6-one and (3S,8R)-8-(((tert- butyldiphenylsilyl)oxy)methyl)-4-((4-methoxybenzyl)amino)-3-methyl-l,3,8,9-tetrahydro- 6H-furo[3,4-d]pyrano[3,4-b]pyridin-6-one (770 mg, 78%) as a colorless oil. MS ESI calculated for CseH^^OsSi [M+H]⁺, 609.27; found, 609.30.

Step-12:

[0841] To a stirred solution of 1 : 1 : 1 : 1 mixture of (3R,8S)-8-(((tertbutyldiphenylsilyl)oxy)methyl)-4-((4-methoxybenzyl)amino)-3-methyl-l,3,8,9-tetrahydro- 6H-furo[3,4-d]pyrano[3,4-b]pyridin-6-one, (3R,8R)-8-(((tert-butyldiphenylsilyl)oxy)methyl)- 4-((4-methoxybenzyl)amino)-3-methyl- 1,3,8 ,9-tetrahydro-6H-furo [3 ,4-d]pyrano [3 ,4- b]pyridin-6-one, (3S,8S)-8-(((tert-butyldiphenylsilyl)oxy)methyl)-4-((4- methoxybenzyl)amino)-3-methyl-l,3,8,9-tetrahydro-6H-furo[3,4-d]pyrano[3,4-b]pyridin-6- one and (3S,8R)-8-(((tert-butyldiphenylsilyl)oxy)methyl)-4-((4-methoxybenzyl)amino)-3- methyl-1 ,3,8,9-tetrahydro-6H-furo[3,4-d]pyrano[3,4-b]pyridin-6-one (750 mg, 1.23 mmol) in THF (4 mL) were added a solution of CaCk (410 mg, 3.69 mmol) in EtOH (4 mL) and NaBH4 (140 mg, 3.69 mmol) at 0 °C. The resulting mixture was stirred at room temperature for 1 h. The reaction was quenched by the addition of water at 0 °C. The resulting mixture was extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous NazSC After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-75% ethyl acetate in petroleum ether to afford a 1: 1:1:1 mixture of (S)-l-((tert-butyldiphenylsilyl)oxy)-3-((R)-6- (hydroxymethyl)-4-((4-methoxybenzyl)amino)-3-methyl-l,3-dihydrofuro[3,4-c]pyridin-7- yl)propan-2-ol, (R)- 1 -((tert-butyldiphenylsilyl)oxy)-3-((R)-6-(hydroxymethyl)-4-((4- methoxybenzyl)amino)-3-methyl-l,3-dihydrofuro[3,4-c]pyridin-7-yl)propan-2-ol, (S)-l- ((tert-butyldiphenylsilyl)oxy)-3-((S)-6-(hydroxymethyl)-4-((4-methoxybenzyl)amino)-3- methyl-l,3-dihydrofuro[3,4-c]pyridin-7-yl)propan-2-ol and (R)-l-((tert- butyldiphenylsilyl)oxy)-3-((S)-6-(hydroxymethyl)-4-((4-methoxybenzyl)amino)-3-methyl- l,3-dihydrofuro[3,4-c]pyridin-7-yl)propan-2-ol (720 mg, 95%) as a colorless oil. MS ESI calculated for CssH^NzOsSi [M+H]⁺, 613.30; found, 613.25.

Step-13:

[0842] To a stirred solution of 1 : 1 : 1 : 1 mixture of (S)-l-((tert-butyldiphenylsilyl)oxy)-3- ((R)-6-(hydroxymethyl)-4-((4-methoxybenzyl)amino)-3-methyl-l,3-dihydrofuro[3,4- c]pyridin-7-yl)propan-2-ol, (R)-l-((tert-butyldiphenylsilyl)oxy)-3-((R)-6-(hydroxymethyl)-4- ((4-methoxybenzyl)amino)-3-methyl- 1 ,3-dihydrofuro[3,4-c]pyridin-7-yl)propan-2-ol, (S)- 1 - ((tert-butyldiphenylsilyl)oxy)-3-((S)-6-(hydroxymethyl)-4-((4-methoxybenzyl)amino)-3- methyl-l,3-dihydrofuro[3,4-c]pyridin-7-yl)propan-2-ol and (R)-l-((tert- butyldiphenylsilyl)oxy)-3-((S)-6-(hydroxymethyl)-4-((4-methoxybenzyl)amino)-3-methyl- l,3-dihydrofuro[3,4-c]pyridin-7-yl)propan-2-ol (720 mg, 1.17 mmol) in toluene (14 mL) was added 2-(tributyl-X⁵-phosphaneylidene)acetonitrile (CAS No. 157141-27-0) (567 mg, 2.35 mmol) at room temperature. The resulting mixture was stirred at 110 °C for 16 h under nitrogen atmosphere. The resulting mixture was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-60% ethyl acetate in petroleum ether to afford a 1: 1:1:1 mixture of (3R,8S)-8-(((tert- butyldiphenylsilyl)oxy)methyl)-N-(4-methoxybenzyl)-3-methyl-3,6,8,9-tetrahydro-lH- furo[3,4-d]pyrano[3,4-b]pyridin-4-amine, (3R,8R)-8-(((tert-butyldiphenylsilyl)oxy)methyl)- N-(4-methoxybenzyl)-3-methyl-3,6,8,9-tetrahydro-lH-furo[3,4-d]pyrano[3,4-b]pyridin-4- amine, (3S,8S)-8-(((tert-butyldiphenylsilyl)oxy)methyl)-N-(4-methoxybenzyl)-3-methyl- 3,6,8,9-tetrahydro-lH-furo[3,4-d]pyrano[3,4-b]pyridin-4-amine and (3S,8R)-8-(((tert- butyldiphenylsilyl)oxy)methyl)-N-(4-methoxybenzyl)-3-methyl-3,6,8,9-tetrahydro-lH- furo[3,4-d]pyrano[3,4-b]pyridin-4-amine (410 mg, 58%) as a colorless oil. MS ESI calculated for C36H₄2N2O₄Si [M+H]⁺, 595.29; found, 595.20.

Step-14:

[0843] To a stirred solution of 1 : 1 : 1 : 1 mixture of (3R,8S)-8-(((tert- butyldiphenylsilyl)oxy)methyl)-N-(4-methoxybenzyl)-3-methyl-3,6,8,9-tetrahydro-lH- furo[3,4-d]pyrano[3,4-b]pyridin-4-amine, (3R,8R)-8-(((tert-butyldiphenylsilyl)oxy)methyl)-

N-(4-methoxybenzyl)-3-methyl-3,6,8,9-tetrahydro-lH-furo[3,4-d]pyrano[3,4-b]pyridin-4- amine, (3S,8S)-8-(((tert-butyldiphenylsilyl)oxy)methyl)-N-(4-methoxybenzyl)-3-methyl-

3,6,8,9-tetrahydro-lH-furo[3,4-d]pyrano[3,4-b]pyridin-4-amine and (3S,8R)-8-(((tert- butyldiphenylsilyl)oxy)methyl)-N-(4-methoxybenzyl)-3-methyl-3,6,8,9-tetrahydro-lH- furo[3,4-d]pyrano[3,4-b]pyridin-4-amine (1.20 g, 2.01 mmol) and TEA (0.82 g, 8.07 mmol) in THF (10 mL) were added BociO (1.54 g, 7.05 mmol) and DMAP (0.02 g, 0.20 mmol) at room temperature under nitrogen atmosphere. The resulting mixture was stirred at 60 °C for 16 h under nitrogen atmosphere. The resulting mixture was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-16% ethyl acetate in petroleum ether to afford a 1:1:1: 1 mixture of tert-butyl ((3R,8S)-8-(((tert- butyldiphenylsilyl)oxy)methyl)-3-methyl-3,6,8,9-tetrahydro-lH-furo[3,4-d]pyrano[3,4- b]pyridin-4-yl)(4-methoxybenzyl)carbamate, tert-butyl ((3R,8R)-8-(((tert- butyldiphenylsilyl)oxy)methyl)-3-methyl-3,6,8,9-tetrahydro-lH-furo[3,4-d]pyrano[3,4- b]pyridin-4-yl)(4-methoxybenzyl)carbamate, tert-butyl ((3S,8S)-8-(((tert- butyldiphenylsilyl)oxy)methyl)-3-methyl-3,6,8,9-tetrahydro-lH-furo[3,4-d]pyrano[3,4- b]pyridin-4-yl)(4-methoxybenzyl)carbamate and tert-butyl ((3S,8R)-8-(((tert- butyldiphenylsilyl)oxy)methyl)-3-methyl-3,6,8,9-tetrahydro-lH-furo[3,4-d]pyrano[3,4- b]pyridin-4-yl)(4-methoxybenzyl)carbamate (952 mg, 67%) as a white oil. MS ESI calculated for C4iH₅oN20₆Si [M+H]⁺, 695.34; found, 695.35.

Step-15:

[0844] To a stirred solution of 1 : 1 : 1 : 1 mixture of tert-butyl ((3R,8S)-8-(((tert- butyldiphenylsilyl)oxy)methyl)-3-methyl-3,6,8,9-tetrahydro-lH-furo[3,4-d]pyrano[3,4- b]pyridin-4-yl)(4-methoxybenzyl)carbamate, tert-butyl ((3R,8R)-8-(((tert- butyldiphenylsilyl)oxy)methyl)-3-methyl-3,6,8,9-tetrahydro-lH-furo[3,4-d]pyrano[3,4- b]pyridin-4-yl)(4-methoxybenzyl)carbamate, tert-butyl ((3S,8S)-8-(((tert- butyldiphenylsilyl)oxy)methyl)-3-methyl-3,6,8,9-tetrahydro-lH-furo[3,4-d]pyrano[3,4- b]pyridin-4-yl)(4-methoxybenzyl)carbamate and tert-butyl ((3S,8R)-8-(((tert- butyldiphenylsilyl)oxy)methyl)-3-methyl-3,6,8,9-tetrahydro-lH-furo[3,4-d]pyrano[3,4- b]pyridin-4-yl)(4-methoxybenzyl)carbamate (950 mg, 1.36 mmol) in THF (10 mL) was added TBAF (714 mg, 2.73 mmol) at room temperature under nitrogen atmosphere. The resulting mixture was stirred at room temperature for 1 h under nitrogen atmosphere. The resulting mixture was concentrated under reduced pressure The residue was purified by silica gel column chromatography, eluted with 0-64% ethyl acetate in petroleum ether to afford a 1 : 1: 1 : 1 mixture of tert-butyl ((3R,8S)-8-(hydroxymethyl)-3-methyl-3,6,8,9-tetrahydro-lH- furo[3,4-d]pyrano[3,4-b]pyridin-4-yl)(4-methoxybenzyl)carbamate, tert-butyl ((3R,8R)-8- (hydroxymethyl)-3-methyl-3,6,8,9-tetrahydro-lH-furo[3,4-d]pyrano[3,4-b]pyridin-4-yl)(4- methoxybenzyl)carbamate, tert-butyl ((3S,8S)-8-(hydroxymethyl)-3-methyl-3, 6,8,9- tetrahydro-lH-furo[3,4-d]pyrano[3,4-b]pyridin-4-yl)(4-methoxybenzyl)carbamate and tertbutyl ((3S,8R)-8-(hydroxymethyl)-3-methyl-3,6,8,9-tetrahydro-lH-furo[3,4-d]pyrano[3,4- b]pyridin-4-yl)(4-methoxybenzyl)carbamate (520 mg, 83%) as a white oil. MS ESI calculated for C25H32N2O6 [M+H]⁺, 457.23; found, 457.20.

[0845] To a stirred solution of a 1: 1 : 1 : 1 mixture of tert-butyl ((3R,8S)-8-(hydroxymethyl)- 3-methyl-3,6,8,9-tetrahydro-lH-furo[3,4-d]pyrano[3,4-b]pyridin-4-yl)(4- methoxybenzyl)carbamate, tert-butyl ((3R,8R)-8-(hydroxymethyl)-3-methyl-3, 6,8,9- tetrahydro-lH-furo[3,4-d]pyrano[3,4-b]pyridin-4-yl)(4-methoxybenzyl)carbamate, tert-butyl ((3S,8S)-8-(hydroxymethyl)-3-methyl-3,6,8,9-tetrahydro-lH-furo[3,4-d]pyrano[3,4- b]pyridin-4-yl)(4-methoxybenzyl)carbamate and tert-butyl ((3S,8R)-8-(hydroxymethyl)-3- methyl-3,6,8,9-tetrahydro-lH-furo[3,4-d]pyrano[3,4-b]pyridin-4-yl)(4- methoxybenzyl)carbamate (520 mg, 1.14 mmol) in MeCN (5 mL) and H2O (2.5 mL) were added BAIB (550 mg, 1.71 mmol) and TEMPO (71 mg, 0.46 mmol) at 0 °C. The resulting mixture was stirred at room temperature for 16 h. The reaction mixture was purified by reverse phase column chromatography with the following conditions: [column, Cl 8 silica gel; mobile phase, MeCN in Water (10 mmol/L NH4HCO3), 5% to 45% gradient in 30 min; detector, UV 254 nm], and then acidified with citric acid to afford a 1 : 1: 1 : 1 mixture of (3R,8S)-4-((tert-butoxycarbonyl)(4-methoxybenzyl)amino)-3-methyl-3,6,8,9-tetrahydro-lH- furo[3,4-d]pyrano[3,4-b]pyridine-8-carboxylic acid, (3R,8R)-4-((tert-butoxycarbonyl)(4- methoxybenzyl)amino)-3-methyl-3,6,8,9-tetrahydro-lH-furo[3,4-d]pyrano[3,4-b]pyridine-8- carboxylic acid, (3S,8S)-4-((tert-butoxycarbonyl)(4-methoxybenzyl)amino)-3-methyl- 3,6,8,9-tetrahydro-lH-furo[3,4-d]pyrano[3,4-b]pyridine-8-carboxylic acid and (3S,8R)-4- ((tert-butoxycarbonyl)(4-methoxybenzyl)amino)-3-methyl-3,6,8,9-tetrahydro-lH-furo[3,4- d]pyrano[3,4-b]pyridine-8-carboxylic acid (CA12) (269 mg, 50%) as a white solid. MS ESI calculated for C25H30N2O7 [M+H]⁺, 471.21; found, 471.10. 'H NMR (400 MHz, DMSO-d₆) 5 13.07 (br, 1 H), 7.18 - 7.09 (m, 2H), 6.93 - 6.75 (m, 2H), 5.23 - 4.62 (m, 7H), 4.32 - 4.19 (m, 1H), 3.72 - 3.66 (m, 3H), 2.96 - 2.73 (m, 2H), 1.39 (s, 9H), 1.00 - 0.75 (m, 3H).

Amine intermediate synthesis

Intermediate Al: 1:1 mixture of (4aR,10bR)-8-methoxy-2,3,4,4a,6,10b-hexahydro-lH- isochromeno[4,3-b]pyridine and (4aS,10bS)-8-methoxy-2,3,4,4a,6,10b-hexahydro-lH- isochromeno[4,3-b]pyridine

Step 1: methyl 5-methoxy-2-(4,4,5,5-tetramethyl-l,3,2-dioxaborolan-2-yl)benzoate

[0846] To a stirred solution of methyl 2-bromo-5-methoxybenzoate (7.50 g, 30.60 mmol) in anhydrous 1,4-dioxane (50 mL) were added Pd(dppf)Ch (0.45 g, 0.61 mmol), AcOK (9.01 g, 91.80 mmol) and BPD (9.33 g, 36.72 mmol) at room temperature. The reaction mixture was stirred at 80 °C for 12 h under hydrogen. After completion of reaction, the reaction mixture was quenched by addition of water and extracted with ethyl acetate. The combined organic phase was washed with brine, dried over anhydrous sodium sulfate, and concentrated under reduced pressure. The residue was purified by flash column chromatography with 5% to 35% EtOAc in petroleum ether to afford methyl 5-methoxy-2-(4,4,5,5-tetramethyl-l,3,2- dioxaborolan-2-yl)benzoate (6.1 g, 68%) as a yellow solid. MS (ESI) calculated for (C15H21BO5) [M+H]⁺, 293.15; found, 293.10.

Step 2: methyl 5-methoxy-2-[3-(methoxymethoxy)pyridin-2-yl]benzoate

[0847] To a stirred mixture of methyl 5-methoxy-2-(4,4,5,5-tetramethyl-l,3,2- dioxaborolan-2-yl)benzoate (7.8 g, 26.70 mmol) and 2-bromo-3-(methoxymethoxy)pyridine (6.98 g, 32.04 mmol) in 1,4-dioxane (100 mL) and water (4 mL) were added K2CO3 (15.06 g, 108.93 mmol), Pd(OAc)2 (599 mg, 2.67 mmol) and triphenylphosphine (3.00 g, 11.48 mmol) at room temperature under nitrogen atmosphere. The resulting mixture was stirred at 100 °C overnight under nitrogen. The solvents were removed under vacuum. The residue was purified by silica gel column chromatography, eluted with 0-20% ethyl acetate in petroleum ether to afford methyl 5-methoxy-2-[3-(methoxymethoxy)pyridin-2-yl]benzoate (6.00 g, 74%) as a colorless oil. MS (ESI) calculated for (C16H17NO5) [M+H]⁺, 304.11 ; found, 304.05.

Step 3: 8-methoxy-6H-isochromeno[4,3-b]pyridin-6-one

[0848] To a solution of methyl 5-methoxy-2-[3-(methoxymethoxy)pyridin-2-yl]benzoate (6.00 g, 19.78 mmol) in DCM (60 mL) was added TFA (20 mL). The mixture was stirred at room temperature for 2 h. The mixture was concentrated to afford 8-methoxy-6H- isochromeno[4,3-b]pyridin-6-one (4 g, crude) as a yellow solid. MS (ESI) calculated for (C13H9NO3) [M+H]⁺, 228.06; found, 228.00.

Step 4: 8-methoxy-6H-isochromeno[4,3-b]pyridine

[0849] To a stirred solution of 8-methoxyisochromeno[4,3-b]pyridin-6-one (8.00 g, 35.20 mmol) in anhydrous EtiO (80 mL) was added borane ammonia complex (2.17 g, 70.41 mmol) and TiCh (83 mg, 0.44 mmol) at 0 °C. The reaction mixture was stirred at room temperature for 12 h. After completion of reaction, the reaction mixture was quenched by addition of Na2CC>3 (sat.) and extracted with ethyl acetate. The combined organic phase was washed with brine, dried over anhydrous sodium sulfate. After filtration, the filtrate was concentrated under reduced pressure, the residue was purified by flash column chromatography with 5% to 55% EtOAc in petroleum ether to afford 8-methoxy-6H- isochromeno[4,3-b]pyridine (1.1 g, 14%). MS (ESI) calculated for (C13H11NO2) [M+H]⁺, 214.08; found, 214.15.

Step 5: 1:1 mixture of (4aR,10bR)-8-methoxy-2,3,4,4a,6,10b-hexahydro-lH- isochromeno[4,3-b]pyridine and (4aS,10bS)-8-methoxy-2,3,4,4a,6,10b-hexahydro-lH- isochromeno[4,3-b]pyridine

[0850] To a solution of 8-methoxy-6H-isochromeno[4,3-b]pyridine (800 mg, 3.75 mmol) in MeOH (7 mL) was added HC1 (1.8 mL, cone.) at 25 °C. The reaction mixture was degassed via vacuum evacuation, then backfilled with hydrogen, and this process was repeated three times. The reaction mixture was stirred at 25 °C for 2 h under hydrogen with a balloon (1 atm.). The mixture was filtered. The filtrate was basified with Na2CC>3 (sat.) to pH 10. The mixture was extracted with EtOAc. The combined organic layers were dried anhydrous sodium sulfate, filtered and concentrated under vacuum to afford a 1 : 1 mixture of (4aR,10bR)-8-methoxy-2,3,4,4a,6,10b-hexahydro-lH-isochromeno[4,3-b]pyridine and (4aS,10bS)-8-methoxy-2,3,4,4a,6,10b-hexahydro-lH-isochromeno[4,3-b]pyridine (478 mg, 49%) as an off-white solid. MS ESI calculated for (C13H17NO2) [M+H]⁺, 220.13; found, 220.20.

Intermediate A2: 1:1 mixture of (4aR,10bR)-8-(trifluoromethyl)-2,3,4,4a,6,10b-hexahydro- 1 H-isochromeno[4,3-b]pyridine and (4aS, 10bS)-8-(trifluoromethyl)-2,3,4,4a,6, 1 Ob- hexahydro-lH-isochromeno[4,3-b]pyridine

Step 1: methyl 2-(4,4,5,5-tetramethyl-l,3,2-dioxaborolan-2-yl)-5-(trifluoromethyl)benzoate

[0851] To a stirred mixture of methyl 2-bromo-5-(trifhioromethyl)benzoate (50.2 g, 177 mmol) and BPD (49.5 g, 195 mmol) in dioxane (500 mL) were added AcOK (34.8 g, 355 mmol) and Pd(dppf)Ch-CH2C12 (14.45 g, 17.73 mmol) at room temperature under nitrogen atmosphere. The resulting mixture was stirred at 85 °C for 16 h under nitrogen atmosphere. The resulting mixture was concentrated under vacuum. The residue was purified by silica gel column chromatography, eluted with 0-10% ethyl acetate in petroleum ether to afford methyl 2-(4,4,5,5-tetramethyl-l,3,2-dioxaborolan-2-yl)-5-(trifluoromethyl)benzoate (49.2 g, 84%) as a light yellow solid. MS ESI calculated for C15H18BF3O4 [M+H]⁺, 331.13; found, 331.05.

Step 2: 2-bromo-3-(methoxymethoxy)pyridine

[0852] To a stirred solution of 2-bromopyridin-3-ol (50 g, 287 mmol) and K2CO3 (79.4 g,

574 mmol) in MeCN (500 mL) was added bromo(methoxy)methane (39.5 g, 316 mmol). The resulting mixture was stirred at room temperature for 3 h. The reaction mixture was filtered. The filtrate was concentrated under vacuum. The resulting residue was purified by Combi Flash (Biotage Isolera Prime) with a 330 g silica gel column and eluted with 0-34% ethyl acetate in petroleum ether to afford 2-bromo-3-(methoxymethoxy)pyridine (38.5 g, 60%) as a white solid. MS ESI calculated for C₇H₈BrNO₂ [M+H]⁺, 217.97, 219.97; found, 217.80, 219.80.

Step 3: methyl 2-[3-(methoxymethoxy)pyridin-2-yl]-5-(trifluoromethyl)benzoate

[0853] To a stirred solution of methyl 2-(4,4,5,5-tetramethyl-l,3,2-dioxaborolan-2-yl)-5- (trifhioromethyl)benzoate (20.1 g, 60.88 mmol) and 2-bromo-3-(methoxymethoxy)pyridine (13.28 g, 60.88 mmol) in dioxane (200 mL) were added K2CO3 (16.83 g, 121.77 mmol) and Pd(dppf)C12-CH2Ch (4.96 g, 6.089 mmol) at room temperature under nitrogen atmosphere. The resulting mixture was stirred at 100 °C overnight. The resulting mixture was concentrated under reduced pressure. The resulting residue was purified by normal phase flash column chromatography with a 330 g silica gel column and eluted with 0-25% ethyl acetate in petroleum ether to afford methyl 2-[3-(methoxymethoxy)pyridin-2-yl]-5- (trifhioromethyl)benzoate (18.7 g, 89%) as a yellow oil. MS ESI calculated for C16H14F3NO4 [M+H]⁺, 342.09; found, 342.30.

Step 4: 8-(trifhioromethyl)isochromeno[4,3-b]pyridin-6-one

[0854] To a stirred solution of methyl 2-[3-(methoxymethoxy)pyridin-2-yl]-5- (trifhioromethyl)benzoate (18.7 g, 54.8 mmol) in DCM (180 mL) was added TFA (60 mL) at 0 °C under nitrogen atmosphere. The resulting mixture was stirred at room temperature overnight. The reaction was concentrated under vacuum. The residue was diluted by water and extracted with CH2CI2. The combined organic layers were washed with NaHCCh (sat.), dried over anhydrous Na2SO4. After filtration, the filtrate was concentrated under reduced pressure to afford 8-(trifhioromethyl)isochromeno[4,3-b]pyridin-6-one (8.6 g, 58%) as a yellow solid. MS ESI calculated for C13H6F3NO2 [M+H]+, 266.04; found, 266.00.

Step 5: Synthesis of 8-(trifluoromethyl)-6H-isochromeno[4,3-b]pyridine

[0855] To a stirred solution of 8-(trifluoromethyl)isochromeno[4,3-b]pyridin-6-one (8.6 g, 32.4 mmol) and NH3-BH3 (2.00 g, 64.9 mmol) in Et2O (100 mL) was added TiCU (12.3 g, 64.9 mmol) dropwise at 0 °C under nitrogen atmosphere. The reaction was stirred at room temperature for 16 h. The reaction was quenched by the addition of water/ice at room temperature. The resulting mixture was extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SO4. After filtration, the filtrate was concentrated under reduced pressure. The resulting residue was purified by normal phase flash column chromatography with a 120 g silica gel column and eluted with 0-20% ethyl acetate in petroleum ether within 50 min to afford 8-(trifluoromethyl)-6H-isochromeno[4,3- b]pyridine (3.8 g, 46%) as a white solid. MS ESI calculated for C13H8F3NO [M+H]⁺, 252.06; found, 251.95.

Step 6: rac-8-(trifluoromethyl)-6H-isochromeno[4,3-b]pyridine (A2)

[0856] To a stirred solution of 8-(trifluoromethyl)-6H-isochromeno[4,3-b]pyridine (3.8 g, 15.12 mmol) in AcOH (30 L) was added PtC>2 (0.34 g, 1.51 mmol) at room temperature. The resulting mixture was stirred at room temperature overnight under hydrogen atmosphere. The resulting mixture was filtered, and the filtrate was concentrated under reduced pressure. The residue was dissolved in ethyl acetate and basified with NaHCCh (sat.). The resulting mixture was extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SO4. After filtration, the filtrate was concentrated under reduced pressure to afford a 1:1 mixture of (4aR,10bR)-8-(trifluoromethyl)-2,3,4,4a,6,10b-hexahydro- 1 H-isochromeno[4,3-b]pyridine and (4aS, 10bS)-8-(trifluoromethyl)-2,3,4,4a,6, 10b- hexahydro-lH-isochromeno[4,3-b]pyridine (3 g, 70%) as a light grey solid. MS ESI calculated for C13H14F3NO [M+H]⁺, 258.10; found, 258.05. *H NMR (300 MHz, DMSO-d₆) 8 7.59 - 7.48 (m, 2H), 7.44 (d, J= 1.8 Hz, 1H), 4.98 - 4.67 (m, 2H), 3.64 - 3.53 (m, 2H), 2.93 - 2.82 (m, 1H), 2.70 - 2.61 (m, 1H), 2.03 - 1.91 (m, 1H), 1.83 - 1.67 (m, 1H), 1.65 - 1.52 (m, 1H), 1.40 - 1.28 (m, 1H).

Intermediate A2 isomer 1: rel-(4aS,10bS)-8-(trifluoromethyl)-2,3,4,4a,6,10b-hexahydro- lH-isochromeno[4,3-b]pyridine, isomer 1 (A2, isomer 1):

Intermediate A2, isomer 2: rel-(4aR,10bR)-8-(trifluoromethyl)-2,3,4,4a,6,10b-hexahydro- lH-isochromeno[4,3-b]pyridine, isomer 2 (A2, isomer 2):

A2, isomer 2

[0857] A 1:1 mixture of (4aS,10bS)-8-(trifluoromethyl)-2,3,4,4a,6,10b-hexahydro-lH- isochromeno[4,3-b]pyridine and (4aR, 10bR)-8-(trifluoromethyl)-2,3,4,4a,6, lOb-hexahydro- lH-isochromeno[4,3-b]pyridine (980 mg) was purified by Prep-chiral SFC with the following conditions [Column: Column: CHIRALPAK IG, 3*25 cm, 5 m; Mobile Phase A: CO2, Mobile Phase B: MeOH (0.1% 2M NHs-MeOH); Flow rate: 80 mL/min; Gradient: isocratic 15% B; RTl(min): 4; RT2(min): 7; Sample Solvent: MeOH; Injection Volume: 1.5 mL; Number Of Runs: 20] to afford rel-(4aS,10bS)-8-(trifluoromethyl)-2,3,4,4a,6,10b-hexahydro- lH-isochromeno[4,3-b]pyridine, isomer 1 (A2, isomer 1) (205 mg, 22%) as a yellow oil. MS ESI calculated for C13H14F3NO [M+H]⁺, 258.10; found, 258.05. 'H NMR (400 MHz, DMSO- 6) 8 7.57 - 7.49 (m, 2H), 7.46 (s, 1H), 4.92 (d, J = 15.6 Hz, 1H), 4.72 (d, J = 15.6 Hz, 1H), 3.61 - 3.60 (m, 1H), 3.57 - 3.56 (m, 1H), 2.90 - 2.85 (m, 1H), 2.72 - 2.59 (m, 1H), 1.99 - 1.93 (m, 1H), 1.79 - 1.72 (m, 1H), 1.61 - 1.51 (m, 1H), 1.36 - 1.30 (m, 1H). Absolute stereochemistry was not determined.

[0858] The chiral resolution also afforded rel-(4aR,10bR)-8-(trifluoromethyl)- 2,3,4,4a,6,10b-hexahydro-lH-isochromeno[4,3-b]pyridine, isomer 2 (A2, isomer 2) (305 mg, 33%) as a yellow oil. MS ESI calculated for C13H14F3NO [M+H]⁺, 258.10; found, 258.05. 'H NMR (400 MHz, DMSO-d₆) 8 7.57 - 7.49 (m, 2H), 7.46 (s, 1H), 4.92 (d, J = 15.6 Hz, 1H), 4.72 (d, J = 15.6 Hz, 1H), 3.61 - 3.60 (m, 1H), 3.57 - 3.56 (m, 1H), 2.90 - 2.85 (m, 1H), 2.72 - 2.59 (m, 1H), 1.99 - 1.93 (m, 1H), 1.79 - 1.72 (m, 1H), 1.61 - 1.51 (m, 1H), 1.36 - 1.30 (m, 1H). Absolute stereochemistry was not determined.

Intermediate A3: 5-((2R,5S)-5-methylpiperidin-2-yl)-2-( 1 -methylpiperidin-4- yl)benzo[d]thiazole

Step 1 : (5S)-5-methyl-2-(trifluoromethanesulfonyloxy)-5,6-dihydro-4H-pyridine-l- carboxylate

[0859] To a stirred solution of tert-butyl (5S)-5-methyl-2-oxopiperidine-l-carboxylate (Supplier: Shanghai Tianze biological medicine Co., LTD cas# 572246-00-4)) (3.00 g, 14.06 mmol) in THF (40 mL) was added KHMDS (56.28 mL, 28.14 mmol, 0.5M in toluene) dropwise at -78 °C under nitrogen atmosphere. After stirring at -78 °C for 2 h, a solution of 1,1,1-trifluoro-N-phenyl-N-trifluoromethanesulfonylmethanesulfonamide (7.54 g, 21.09 mmol) in THF (10 mL) was added dropwise to above mixture at -78 °C. The resulting mixture was stirred at 25 °C for 16 h. The reaction was quenched by the addition of NH4CI (sat.) at 25 °C. The resulting mixture was extracted with DCM. The combined organic layers were dried over anhydrous Na2SC>4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-10% EtOAc in PE to afford tert-butyl (5S)-5-methyl-2-(trifhioromethanesulfonyloxy)-5,6- dihydro-4H-pyridine-l-carboxylate (3.76 g, 74%) as a colorless oil. MS ESI calculated for C12H18F3NO5S [M+H]⁺, 346.09; found, 346.10. 'H NMR (400 MHz, DMSO- ₆) 8 (ppm) 5.51 (t, 7 = 3.8 Hz, 1H), 3.67 (dd, 7 = 12.8, 3.0 Hz, 1H), 3.06 (dd, 7= 12.8, 8.4 Hz, 1H), 2.46 - 2. 1 (m, 1H), 1.93 - 1.75 (m, 2H), 1.43 (s, 9H), 0.92 (d, 7= 6.4 Hz, 3H).

Step 2: 5-chloro-2-(l-methylpiperidin-4-yl)benzo[d]thiazole

[0860] A mixture of PPA (28.82 g, 250.58 mmol) and P2O5 (35.57 g, 250.58 mmol) was stirred at room temperature for 10 minutes. Then 2-amino-4-chlorobenzenethiol (10.00 g, 62.64 mmol) and l-methylpiperidine-4-carboxylic acid (10.76 g, 75.17 mmol) were added to the mixture at room temperature. The resulting mixture was stirred at 110 °C overnight under nitrogen atmosphere. The mixture was allowed to cool down to room temperature. The resulting mixture was diluted with a mixture of water and DCM. The mixture was basified with NaOH (aq.) to pH 10. The resulting mixture was extracted with CH2CI2. The organic layers were dried over anhydrous Na2SC>4. After filtration, the filtrate was concentrated under reduced pressure to afford 5-chloro-2-(l-methylpiperidin-4-yl)-l,3-benzothiazole (8.86 g, 50%) as a fight brown solid. MS ESI calculated for C13H15CIN2S [M+H]⁺, 267.06; found, 267.00.

Step 3 : 2-(l -methylpiperidin-4-yl)-5-(4,4,5,5-tetramethyl- 1 ,3,2-dioxaborolan-2- yl)benzo[d]thiazole

[0861] To a stirred mixture of 5-chloro-2-(l-methylpiperidin-4-yl)-l,3-benzothiazole (8.86 g, 33.21 mmol) in dioxane (88 mL) were added BPD (9.28 g, 36.53 mmol), AcOK (6.52 g, 66.42 mmol), XPhos (3.17 g, 6.64 mmol) and Pd2(dba)3 (1.52 g, 1.66 mmol) at room temperature. The resulting mixture was stirred at 90 °C for 4 h under nitrogen atmosphere. The resulting mixture was filtered, the filter cake was washed with 1,4-dioxane. The filtrate was concentrated under reduced pressure. The resulting mixture was diluted with MTBE (140 mL). The product was precipitated by the addition of HC1 (4 M in 1,4- dioxane, 20 mL). The precipitated solids were collected by filtration and washed with MTBE to afford 2-(l-methylpiperidin-4-yl)-5-(4,4,5,5-tetramethyl-l,3,2-dioxaborolan-2-yl)-l ,3- benzothiazole (15.01 g, 80%) as a brown solid. MS ESI calculated for C19H27BN2O2S [M+H]⁺, 359.18; found, 359.30

Step 4: tert-butyl (S)-3-methyl-6-(2-(l-methylpiperidin-4-yl)benzo[d]thiazol-5-yl)-3,4- dihydropyridine- 1 (2H)-carboxylate

[0862] To a stirred mixture of 2-(l-methylpiperidin-4-yl)-5-(4,4,5,5-tetramethyl-l,3,2- dioxaborolan-2-yl)-l,3-benzothiazole (3.42 g, 9.55 mmol) in dioxane (110 mL) and H2O (22 mL) were added K2CO3 (3.96 g, 28.66 mmol), tert-butyl (5S)-5-methyl-2- (trifluoromethanesulfonyloxy)-5,6-dihydro-4H-pyridine-l-carboxylate (3.30 g, 9.55 mmol) and Pd(dppf)Ch (0.70 g, 0.95 mmol). The resulting mixture was stirred at 100 °C for 2 h. The reaction mixture was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with CH2CI2 / MeOH (10: 1) to afford tert-butyl (5S)-5- methyl-2- [2-( 1 -methylpiperidin-4-yl)- 1 ,3-benzothiazol-5-yl] -5 ,6-dihydro-4H-pyridine- 1 - carboxylate (4.6 g) as a brown oil. MS ESI calculated for C24H33N3O2S [M+H]⁺, 428.23; found, 428.38.

Step 5: (S)-5-(5-methyl-3,4,5,6-tetrahydropyridin-2-yl)-2-(l-methylpiperidin-4- yl)benzo[d]thiazole

[0863] To a solution of tert-butyl (5S)-5-methyl-2-[2-(l-methylpiperidin-4-yl)-l,3- benzothiazol-5-yl]-5,6-dihydro-4H-pyridine-l-carboxylate (2.35 g, 5.49 mmol) DCM (20 mL) was added TFA (5 mL). The mixture was stirred at room temperature for 1 h. The resulting mixture was concentrated under vacuum to afford 5-[(5S)-5-methyl-3,4,5,6- tetrahydropyridin-2-yl]-2-(l-methylpiperidin-4-yl)-l,3-benzothiazole (5.6 g, crude) as a brown oil. MS ESI calculated for C19H25N3S [M+H]⁺, 328.18; found, 328.40

Step 6: 5-((2R,5S)-5-methylpiperidin-2-yl)-2-(l-methylpiperidin-4-yl)benzo[d]thiazole (A3)

[0864] To a stirred solution of 5-[(5S)-5-methyl-l,4,5,6-tetrahydropyridin-2-yl]-2-(l- methylpiperidin-4-yl)-l,3-benzothiazole (3.52 g, 10.74 mmol) in MeOH (35 mL) was added NaBF (2.85 g, 75.23 mmol) in portions at -20 °C. The resulting mixture was stirred for 3 h at -20 °C. The reaction was quenched by the addition of water. The mixture was basified with NaHCOs (sat.). The resulting mixture was extracted with EtOAc. The combined organic layers were washed with water, dried over anhydrous Na2SC>4. After filtration, the filtrate was concentrated under reduced pressure to afford 5-[(2R,5S)-5-methylpiperidin-2-yl]-2-(l- methylpiperidin-4-yl)-l,3-benzothiazole (4.6 g, 97%) as a brown solid. MS ESI calculated for C19H27N3S [M+H]⁺, 330.19; found, 330.25. 'H NMR (400 MHz, DMSO- ₆) 8 (ppm) 8.25 (d, J= 1.6 Hz, 1H), 8.14 (d, J= 8.4 Hz, 1H), 7.69 (dd, J = 8.4, 1.6 Hz, 1H), 4.30 (dd, J= 12.0, 3.2 Hz, 1H), 3.43 - 3.35 (m, 2H), 3.29 - 3.18 (m, 1H), 3.11 - 2.94 (m, 2H), 2.74 - 2.71 (m, 1H), 2.68 (s, 3H), 2.32 - 2.28 (m, 2H), 2.23 - 2.15 (m, 2H), 2.08 (s, 3H), 2.06 - 1.82 (m, 2H), 1.42 - 1.32 (m, 1H), 0.96 (d, J = 6.6 Hz, 3H).

Intermediate A4: 1:1 mixture of (4aR,10bR)-8-(trifluoromethyl)-l,2,3,4a,5,10b- hexahydrochromeno[3,4-b] [ 1 ,4]oxazine and (4aS, 10bS)-8-(trifluoromethyl)- 1 ,2, 3, 4a, 5, 1 Ob- hexahydrochromeno[3,4-b] [ 1 ,4]oxazine

Step 1 : 1 :1 mixture of (S)-3-bromo-7-(trifluoromethyl)chroman-4-one and (R)-3-bromo-7- (trifluoromethyl)chroman-4-one

[0865] To a stirred mixture of 7-(trifluoromethyl)-2,3-dihydro-l-benzopyran-4-one (10.11 g, 46.8 mmol) in EtzO (150 mL) was added Br2 (2.40 mL, 46.8 mmol) dropwise at 0 °C under nitrogen atmosphere. The resulting mixture was stirred for 1 h at room temperature. The reaction mixture was poured into NaS2C>3 (sat.) and stirred for 5 minutes. The mixture was extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate. After filtration, the filtrate was concentrated under vacuum. The resulting residue was purified by normal phase flash column chromatography with an 80 g silica gel column and eluted with 0-50% ethyl acetate in petroleum ether to afford a 1:1 mixture of (S)-3-bromo-7-(trifhioromethyl)chroman-4-one and (R)-3-bromo-7- (trifhioromethyl)chroman-4-one (11.80 g, 76%) as a white solid. MS ESI calculated for CioH₆BrF₃02 [M+H]⁺, 294.95, 296.95; found, 294.85, 296.85.

Step 2: 1:1 mixture of (3S,4R)-3-bromo-7-(trifhioromethyl)chroman-4-ol and (3R,4S)-3- bromo-7-(trifluoromethyl)chroman-4-ol

[0866] To a solution of a 1:1 mixture of (S)-3-bromo-7-(trifluoromethyl)chroman-4-one and (R)-3-bromo-7-(trifhioromethyl)chroman-4-one (8.7 g, 29.48 mmol) in EtOH (88 mL) was added NaBFL (0.56 g, 14.74 mmol) at 0 °C. The mixture was stirred at room temperature for 1 h. The resulting mixture was concentrated under reduced pressure. The residue was diluted by water and extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SO4. After filtration, the filtrate was concentrated under reduced pressure to afford a 1 : 1 mixture of (3S,4R)-3-bromo-7- (trifhioromethyl)chroman-4-ol and (3R,4S)-3-bromo-7-(trifluoromethyl)chroman-4-ol (8.0 g, 90%) as a white solid. MS ESI calculated for C10H8BrFaCh [M+H]⁺, 296.97, 298.97; found, 296.90, 298.90.

Step 3: 1:1 mixture of (3R,4R)-4-amino-7-(trifluoromethyl)chroman-3-ol and (3S,4S)-4- amino-7-(trifluoromethyl)chroman-3-ol

[0867] To a solution of a 1:1 mixture of (3S,4R)-3-bromo-7-(trifluoromethyl)chroman-4-ol and (3R,4S)-3-bromo-7-(trifhioromethyl)chroman-4-ol (10 g, 33.66 mmol) and MeCN (4.15 g, 100.98 mmol) in DCE (50 mL) was added cone. H2SO4 (6.60 g, 67.32 mmol) at 25 °C. The mixture was stirred at 25 °C for 3 h. Then water (66.60 mL) was added to the mixture at 25 °C. The mixture was stirred at 60 °C for 14 h. The mixture was cooled to room temperature and extracted with DCM. The aqueous phase was collected and basified by NaOH (aq., 25%) to pH 12. The aqueous layer was extracted with DCM. The combined organic layers were washed with brine, dried over anhydrous Na2SC>4. After filtration, the filtrate was concentrated under reduced pressure to afford a 1 : 1 mixture of (3R,4R)-4-amino-7- (trifhioromethyl)chroman-3-ol and (3S,4S)-4-amino-7-(trifhioromethyl)chroman-3-ol (2.5 g, 31%) as an off-white solid. MS ESI calculated for C10H10F3NO2 [M+H]⁺, 234.07; found, 233.95.

Step 4: 1:1 mixture of (4aR,10bR)-8-(trifluoromethyl)-l,4a,5,10b-tetrahydrochromeno[3,4- b] [1 ,4]oxazin-2(3H)-one and (4aS, 10bS)-8-(trifluoromethyl)-l ,4a, 5, 10b- tetrahydrochromeno[3,4-b] [1 ,4]oxazin-2(3H)-one

[0868] To a solution of a 1:1 mixture of (3R,4R)-4-amino-7-(trifluoromethyl)chroman-3-ol and (3S,4S)-4-amino-7-(trifluoromethyl)chroman-3-ol (2.00 g, 8.57 mmol) and CS2CO3 (5.59 g, 17.15 mmol) in MeCN (20 mL) was added 2-chloroacetyl chloride (0.97 g, 8.57 mmol) dropwise at 25 °C. The mixture was stirred at 25 °C for 1 h. Then the mixture was heated at 50° C and stirred for 12 h. The resulting mixture was filtered, the filter cake was washed with MeCN. The filtrate was concentrated under reduced pressure. The residue was purified by reversed-phase flash column chromatography 10 - 50% MeCN in water (0.1% TFA) to afford a 1:1 mixture of (4aR,10bR)-8-(trifluoromethyl)-l,4a,5,10b-tetrahydrochromeno[3,4- b] [1 ,4]oxazin-2(3H)-one and (4aS, 10bS)-8-(trifluoromethyl)-l ,4a, 5, 10b- tetrahydrochromeno[3,4-b][l,4]oxazin-2(3H)-one (760 mg, 32%) as a white solid. MS ESI calculated for C12H10F3NO3 [M+H]⁺, 274.06; found, 274.00.

Step 5: 1:1 mixture of (4aR,10bR)-8-(trifluoromethyl)-l,2,3,4a,5,10b- hexahydrochromeno[3,4-b] [ 1 ,4]oxazine and (4aS, 10bS)-8-(trifluoromethyl)- 1 ,2, 3, 4a, 5, 10b- hexahydrochromeno[3,4-b] [ 1 ,4]oxazine

A4

[0869] A mixture of NaBH4 (221 mg, 5.85 mmol) and BFs-EfoO (1.03 g, 7.32 mmol) in THF (4 mL) was stirred at 0 °C for 1 h, then a solution of rac-(2S,7S)-12-(trifluoromethyl)- 6,9-dioxa-3-azatricyclo[8.4.0.0^A{2,7}]tetradeca-l(14),10,12-trien-4-one (400 mg, 1.46 mmol) in THF (2mL) was added, and the mixture was stirred at 10 °C for 1 h. The resulting mixture was concentrated under reduced pressure. The crude product was purified by reverse phase flash column chromatography with 5-30% MeCN in water to afford a 1: 1 mixture of (4aR,10bR)-8-(trifluoromethyl)-l ,2, 3, 4a, 5, 10b-hexahydrochromeno[3,4-b] [1 ,4]oxazine and (4aS,10bS)-8-(trifluoromethyl)-l,2,3,4a,5,10b-hexahydrochromeno[3,4-b][l,4]oxazine (300 mg, 79%) as a grey solid. MS ESI calculated for C12H12F3NO2 [M+H]⁺, 260.08; found, 260.00. ¹H NMR (400 MHz, DMSO-d₆) 8 (ppm) 7.87 (d, J= 8.2 Hz, 1H), 7.39 (dd, J= 8.2, 1.8 Hz, 1H), 7.21 (d, J= 1.8 Hz, 1H), 5.10 - 4.90 (m, 1H), 4.47 - 4.17 (m, 3H), 4.05 - 3.81 (m, 2H), 3.15 - 3.09 (m, 1H), 2.81 - 2.73 (m, 1H).

Intermediate A5: 1:1 mixture of (4aR,10bS)-8-bromo-l ,3,4,4a,5,10b-hexahydro-2H- chromeno[4,3-b]pyridine and (4aS,10bR)-8-bromo-l,3,4,4a,5,10b-hexahydro-2H- chromeno[4,3-b]pyridine

Step 1 : methyl 2-(4-bromo-2-methoxyphenyl)pyridine-3-carboxylate

[0870] To a stirred solution of methyl 2-chloropyridine-3-carboxylate (7.43 g, 43.32 mmol) and K2CO3 (8.98 g, 64.98 mmol) in DMF (60 mL) and H2O (6 mL) were added Pd(PPh₃)4 (2.50 g, 2.17 mmol) and 4-bromo-2-methoxyphenylboronic acid (5 g, 21.66 mmol) under nitrogen atmosphere. The resulting mixture was stirred at 50 °C for 16 h under nitrogen atmosphere. The reaction mixture was quenched by the addition of water and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under vacuum. The resulting residue was purified by normal phase flash chromatography which applied to 120 g silica gel column and eluted with 0-40% ethyl acetate in petroleum ether within 35 min to afford methyl 2-(4-bromo-2- methoxyphenyl)pyridine-3-carboxylate (4.6 g, 65%) as a yellow solid. MS (ESI) calc’d for (Ci₄Hi2BrNO₃) [M+H]⁺, 322.00, 324.00; found, 321.95, 323.95.

Step 2: 8-bromochromeno[4,3-b]pyridin-5-one

[0871] To a stirred solution of methyl 2-(4-bromo-2-methoxyphenyl)pyridine-3- carboxylate (4.60 g, 14.28 mmol) in DCM (80 mL) was added BBr₃ (71.39 mL, 71.40 mmol) dropwise at 0 °C. The resulting mixture was stirred at room temperature for 16 h. The reaction was quenched with Water/Ice and neutralized to pH -7 with saturated NaHCO₃ (aq.). The resulting mixture was extracted with CH2CI2. The combined organic layers were washed with brine, dried over anhydrous Na2SO4. After filtration, the filtrate was concentrated under reduced pressure to afford 8-bromochromeno[4,3-b]pyridin-5-one (3.8 g, crude) as a yellow solid. MS (ESI) calc’d for (CnHeBrNCh) [M+H]⁺, 275.96, 277.96; found, 275.95, 277.95.

Step 3: 8-bromo-5H-chromeno[4,3-b]pyridine

[0872] To a stirred solution of 8-bromochromeno[4,3-b]pyridin-5-one (3.8 g, 13.76 mmol) and NH3.BH3 (1.70 g, 55.06 mmol) in Et₂O (50 mL) was added T1CI4 (7.65 mL, 55.06 mmol) dropwise at 0 °C. The resulting mixture was stirred at room temperature for 16 h. The reaction mixture was quenched by the addition of ice water and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under vacuum. The resulting residue was purified by normal phase flash chromatography which applied to 80 g silica gel column and eluted with 0-80% ethyl acetate in petroleum ether within 35 min to afford 8-bromo-5H-chromeno[4,3-b]pyridine (865 mg, 22%) as a yellow solid. MS (ESI) calc’d for (Ci₂H₈BrNO) [M+H]⁺, 261.98, 263.98; found, 261.85, 263.85.

Step 4: 1:1 mixture of (4aR,10bS)-8-bromo-l,3,4,4a,5,10b-hexahydro-2H-chromeno[4,3- b]pyridine and (4aS , 10bR)-8-bromo- 1 ,3 ,4, 4a, 5 , 10b-hexahydro-2H-chromeno[4,3-b]pyridine

[0873] To a solution of 8-bromo-5H-chromeno[4,3-b]pyridine (270 mg, 1.03 mmol) in propan-2-ol (4 mL) and AcOH (4 mL) was added Pt/C (58 mg, 0.30 mmol) at 20 °C under nitrogen. The mixture was placed under hydrogen atmosphere with a balloon (1 atm.). The reaction mixture degassed via vacuum evacuation, then backfilled with hydrogen, and this process was repeated three times. The reaction mixture was stirred at 20 °C for 16 h under hydrogen atmosphere. The resulting mixture was filtered and the filtrate was concentrated under reduced pressure. The resulting residue was dissolved in DMF (1.5 mL) and was purified by reverse phase flash chromatography on 48 g Cl 8 column with 5-80% acetonitrile in water (10 mM NH4HCO3) within 35 min to afford a 1:1 mixture of (4aR,10bS)-8-bromo- 1 ,3, 4, 4a, 5, 10b-hexahydro-2H-chromeno[4,3-b]pyridine and (4aS, 10bR)-8-bromo- l,3,4,4a,5,10b-hexahydro-2H-chromeno[4,3-b]pyridine (50 mg, 16%) as a colorless oil. MS (ESI) calc’d for (Ci₂Hi₄BrNO) [M+H]⁺, 268.03, 270.03; found, 268.15, 270.15. 'H NMR (400 MHz, DMSO- ₆) 5 7.28 (d, J = 8.2 Hz, 1H), 7.04 - 7.00 (m, 1H), 6.92 (dd, J = 9.4, 2.0 Hz, 1H), 4.29 (dd, J= 10.6, 7.8 Hz, 1H), 4.14 - 4.04 (m, 1H), 3.89 - 3.72 (m, 1H), 2.70 - 2.54 (m, 3H), 1.99 - 1.95 (m, 1H), 1.72 - 1.55 (m, 2H), 1.49 - 1.17 (m, 2H).

Intermediate A6, isomer 1: rel-(2R,4aS,10bR)-2-methyl-8-(trifluoromethyl)-l,3,4,4a,5,10b- hexahydro-2H-chromeno[4,3-b]pyridine, isomer 1:

A6, isomer 1 _{; and}

Intermediate A6, isomer 2: rel-(2S,4aR,10bS)-2-methyl-8-(trifluoromethyl)-l,3,4,4a,5,10b- hexahydro-2H-chromeno[4,3-b]pyridine, isomer 2:

A6, isomer 2

Step 1: methyl 2-[2-methoxy-4-(trifluoromethyl)phenyl]-6-methylpyridine-3-carboxylate

[0874] To a stirred solution of 2-methoxy-4-(trifluoromethyl)phenylboronic acid (10 g,

45.5 mmol) in dioxane (100 mL) and H2O (10 mL) were added methyl 2-chloro-6- methylpyridine-3-carboxylate (8.44 g, 45.5 mmol), Pd(dppf)ChCH2C12 (3.70 g, 4.55 mmol) and K2CO3 (12.57 g, 90.9 mmol). The resulting solution was stirred at 100 °C for 2 h under nitrogen atmosphere. The resulting mixture was quenched with water and extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SC>4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-30% ethyl acetate in petroleum ether to afford methyl 2- [2-methoxy-4-(trifluoromethyl)phenyl]-6-methylpyridine-3-carboxylate

(13.5 g, 88%) as an off-white solid. MS ESI calculated for (C16H14F3NO3) [M+H]⁺, 326.09; found, 326.10. 'H NMR (400 MHz, DMSO-d₆) 3 8.08 (d, J= 8.0 Hz, 1H), 7.62 (dd, J = 7.6, 1.2 Hz, 1H), 7.44 - 7.37 (m, 2H), 7.31 (d, J= 1.6 Hz, 1H), 3.75 (s, 3H), 3.65 (s, 3H), 2.57 (s, 3H).

Step 2: 2-methyl-8-(trifluoromethyl)chromeno[4,3-b]pyridin-5-one

[0875] Into a 1000 mL 3-necked round-bottom flask were added methyl 2-[2-methoxy-4- (trifhioromethyl)phenyl]-6-methylpyridine-3-carboxylate (13.50 g, 41.50 mmol) and DCM (135 mL) at room temperature. To the above mixture was added BB (62.38 g, 249.01 mmol) dropwise at 0 °C. The resulting mixture was stirred at 25 °C for 16 h under nitrogen atmosphere. The reaction was quenched with water at 0 °C. The resulting mixture was extracted with CH2CI2. The combined organic layers were dried over anhydrous Na2SC>4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-40% ethyl acetate in petroleum ether to afford 2-methyl-8-(trifhioromethyl)chromeno[4,3-b]pyridin-5-one (9.5 g, 78%) as a white solid. MS ESI calculated for (C14H8F3NO2) [M+H]⁺, 280.05; found, 280.15. ’H NMR (400 MHz, Chloroform-d) 8 8.83 - 8.63 (m, 1H), 8.52 (d, J= 8.0 Hz, 1H), 7.70 - 7.56 (m, 2H), 7.46 (d, J = 8.4 Hz, 1H), 2.81 (s, 3H).

Step 3: 2-methyl-8-(trifluoromethyl)-5H-chromeno[4,3-b]pyridine

[0876] Into a 1000 mL vial were added 2-methyl-8-(trifluoromethyl)chromeno[4,3- b]pyridin-5-one (20 g, 71.62 mmol), NH3.BH3 (4.42 g, 143.25 mmol) and Et2O (200 mL) at room temperature. To the above mixture was added T1CI4 (1 mol/L in DCM) (143 mL, 143.26 mmol) dropwise at 0 °C. The resulting mixture was stirred for additional 2 days at room temperature. The resulting mixture was quenched with water and extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SC>4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-30% ethyl acetate in petroleum ether to afford 2-methyl-8-(trifluoromethyl)-5H-chromeno[4,3-b]pyridine (9.8 g, 46%) as a white solid. MS ESI calculated for (C14H10F3NO) [M+H]⁺, 266.07; found, 266.10. ’H NMR (400 MHz, DMSO-d₆) 8 8.28 (d, J= 8.0 Hz, 1H), 7.61 (d, J = 7.6 Hz, 1H), 7.42 (dd, J= 8.0, 1.8 Hz, 1H), 7.35 - 7.21 (m, 2H), 5.35 (s, 2H), 2.54 (s, 3H).

Step 4: 1:1 mixture of rel-(2R,4aS,10bR)-2-methyl-8-(trifluoromethyl)-l,3,4,4a,5,10b- hexahydro-2H-chromeno[4,3-b]pyridine, isomer 1 and rel-(2S,4aR,10bS)-2-methyl-8- (trifluoromethyl)-l,3,4,4a,5,10b-hexahydro-2H-chromeno[4,3-b]pyridine, isomer 2

A6, isomer 1 A6, isomer 2

[0877] To a solution of 2-methyl-8-(trifluoromethyl)-5H-chromeno[4,3-b]pyridine (5.0 g, 18.85 mmol) in AcOH (30 mL) and 2-propanol (30 mL) was added Pt/C (110 mg, 0.56 mmol) at 20 °C under nitrogen atmosphere. The reaction mixture was degassed via vacuum evacuation, then backfilled with hydrogen, and this process was repeated three times. The reaction mixture was stirred at 20 °C for 16 h under hydrogen with a balloon (1 atm.). The suspension was filtered. The filtrate was collected and concentrated under vacuum. The resulting residue was purified by Combi Flash (Biotage Isolera Prime) which applied to 120 g silica gel column and eluted with 0-30% ethyl acetate in petroleum ether within 25 min to afford a 1:1 mixture of rel-(2R,4aS,10bR)-2-methyl-8-(trifluoromethyl)-l,3,4,4a,5,10b- hexahydro-2H-chromeno[4,3-b]pyridine, isomer 1 and rel-(2S,4aR,10bS)-2-methyl-8- (trifluoromethyl)-l,3,4,4a,5,10b-hexahydro-2H-chromeno[4,3-b]pyridine, isomer 2 (900 mg, 14%) as a yellow oil. MS (ESI) calc’d for (C14H16F3NO) [M+H]⁺, 272.12; found, 272.15. 'H NMR (400 MHz, DMSO-d₆) 8 7.44 (d, J= 8.0 Hz, 1H), 7.18 - 7.11 (m, 1H), 7.05 (d, J = 1.6 Hz, 1H), 4.58 - 4.45 (m, 1H), 4.04 - 3.94 (m, 1H), 3.73 (d, J= 3.2 Hz, 1H), 2.83 - 2.66 (m, 1H), 2.10 - 2.08 (m, 1H), 2.04 - 1.93 (m, 1H), 1.83 - 1.69 (m, 2H), 1.42 - 1.38 (m, 1H), 1.38 - 1.34 (m, 1H), 1.00 (d, J= 6.0 Hz, 3H).

Step 5: rel-(2R,4aS,10bR)-2-methyl-8-(trifluoromethyl)-l,3,4,4a,5,10b-hexahydro-2H- chromeno[4,3-b]pyridine, isomer 1 (A6 isomer 1):

A6, isomer rel-(2S,4aR, 10bS)-2-methyl-8-(trifluoromethyl)- 1 ,3, 4, 4a, 5, 10b-hexahydro-2H-chromeno[4,3- b]pyridine, isomer 2 (A6 isomer 2):

A6, isomer 2

[0878] A 1 : 1 mixture of rel-(2R,4aS, 10bR)-2-methyl-8-(trifluoromethyl)- 1 ,3, 4, 4a, 5, 10b- hexahydro-2H-chromeno[4,3-b]pyridine, isomer 1 and rel-(2S,4aR,10bS)-2-methyl-8- (trifluoromethyl)-l,3,4,4a,5,10b-hexahydro-2H-chromeno[4,3-b]pyridine, isomer 2 (900 mg, 3.31 mmol) was separated by prep-chiral SFC with the following conditions: [Column: CHIRALPAK IG, 5*25 cm, 10 pm; Mobile Phase A: CO₂, Mobile Phase B: MeOH (0.1% 2M NHs-MeOH); Flow rate: 100 mL/min; Gradient: isocratic 20% B; RT1 (min): 6.6; RT2 (min): 7.7; Sample Solvent: MeOH; Injection Volume: 1 mL; Number Of Runs: 38] to afford rel-(2R,4aS,10bR)-2-methyl-8-(trifhioromethyl)-l,3,4,4a,5,10b-hexahydro-2H- chromeno[4,3-b]pyridine, isomer 1 (A6 isomer 1) (185 mg, 20%) as a light yellow oil with retention time at 6.6 minute. The chiral separation also afford rel-(2R,4aS,10bR)-2-methyl-8- (trifhioromethyl)-l,3,4,4a,5,10b-hexahydro-2H-chromeno[4,3-b]pyridine, isomer 2 (A6 isomer 2) (165 mg, 17%) as a light yellow oil with retention time at 7.7 minute.

[0879] rel-(2R,4aS,10bR)-2-methyl-8-(trifluoromethyl)-l,3,4,4a,5,10b-hexahydro-2H- chromeno[4,3-b]pyridine, isomer 1 (A6 isomer 1): MS ESI calculated for (C14H16F3NO) [M+H]⁺, 272.12; found, 272.15. 'H NMR (400 MHz, DMSO-d₆) 8 7.44 (d, J= 8.0 Hz, 1H), 7.15 (dd, 7 = 8.0, 2.0 Hz, 1H), 7.05 (d, J = 1.6 Hz, 1H), 4.58 - 4.41 (m, 1H), 4.09 - 3.95 (m, 1H), 3.73 (d, J = 3.2 Hz, 1H), 2.80 - 2.63 (m, 1H), 2.14 - 2.06 (m, 1H), 2.04 - 1.95 (m, 1H), 1.82 - 1.69 (m, 2H), 1.42 - 1.38 (m, 1H), 1.38 - 1.33 (m, 1H), 0.99 (d, J = 6.0 Hz, 3H). Absolute stereochemistry was not determined.

[0880] rel-(2S,4aR,10bS)-2-methyl-8-(trifluoromethyl)-l,3,4,4a,5,10b-hexahydro-2H- chromeno[4,3-b]pyridine, isomer 2 (A6 isomer 2): MS ESI calculated for (C14H16F3NO) [M+H]⁺, 272.12; found, 272.15. ¹H NMR (400 MHz, DMSO-7₆) 8 7.44 (d, J= 8.0 Hz, 1H),

7.16 (dd, 7= 8.0, 2.0 Hz, 1H), 7.06 (d, 7 = 1.6 Hz, 1H), 4.61 - 4.41 (m, 1H), 4.05 - 3.96 (m, 1H), 3.74 (d, 7 = 3.2 Hz, 1H), 2.83 - 2.64 (m, 1H), 2.16 - 2.05 (m, 1H), 2.05 - 1.92 (m, 1H), 1.82 - 1.68 (m, 2H), 1.42 - 1.38 (m, 1H), 1.38 - 1.33 (m, 1H), 1.00 (d, 7 = 6.0 Hz, 3H).

Absolute stereochemistry was not determined.

Intermediate A7: 5-[(2R,5S)-5-methylpiperidin-2-yl]-l,3-benzothiazole

Step 1: 5-(4,4,5,5-tetramethyl-l,3,2-dioxaborolan-2-yl)-l,3-benzothiazole

[0881] To a stirred solution of 5-bromo-l ,3-benzothiazole (20 g, 93.42 mmol) in dioxane (200 mL) were added bis(pinacolato)diboron (35.59 g, 140.14 mmol), Pd(dppf)Ch (6.84 g, 9.34 mmol) and AcOK (18.34 g, 186.85 mmol) at room temperature. The resulting mixture was stirred at 80 °C for 2 h under nitrogen atmosphere. The resulting mixture was filtered, and the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-40% ethyl acetate in petroleum ether to afford 5- (4,4,5,5-tetramethyl-l,3,2-dioxaborolan-2-yl)-l,3-benzothiazole (21 g, 86%) as a white solid. MS ESI calculated for CI₃HI₆BNO₂S [M+H]⁺, 262.10; found, 262.05.

Step 2: tert-butyl (5S)-2-(l,3-benzothiazol-5-yl)-5-methyl-5,6-dihydro-4H-pyridine-l- carboxylate

[0882] To a stirred solution of 5-(4,4,5,5-tetramethyl-l,3,2-dioxaborolan-2-yl)-l,3- benzothiazole (365 mg, 1.40 mmol) and tert-butyl (5S)-5-methyl-2- (trifhioromethanesulfonyloxy)-5,6-dihydro-4H-pyridine- 1 -carboxylate (Supplier: Shanghai Tianze biological medicine Co., LTD cas# 572246-00-4) (483 mg, 1.40 mmol) in dioxane (3 mL) and H₂O (3 mL) was added K₂CO₃ (387 mg, 2.80 mmol) at room temperature under nitrogen atmosphere. The resulting mixture was stirred at 100 °C for 16 h under nitrogen atmosphere. The reaction mixture was quenched with water, and extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na₂SC>4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-50% ethyl acetate in petroleum ether to afford tert-butyl (5S)-2-(l,3-benzothiazol-5-yl)-5-methyl-5,6-dihydro-4H-pyridine-l- carboxylate (240 mg, 30%) as a white solid. MS ESI calculated for CisH₂₂N₂O₂S [M+H]⁺, 331.14; found, 331.05.

Step 3: 5-[(2R,5S)-5-methylpiperidin-2-yl]-l,3-benzothiazole (A7)

A7

[0883] A solution of tert-butyl (5S)-2-(l,3-benzothiazol-5-yl)-5-methyl-5,6-dihydro-4H- pyridine-1 -carboxylate (240 mg, 0.73 mmol) and TFA (0.6 mL) in DCM (2.4 mL) was stirred at room temperature for 2 h. The resulting mixture was concentrated under vacuum. The residue was dissolved in MeOH (5 mL), and NaBH4 (82 mg, 2.18 mmol) was added in portions at -20 °C under nitrogen atmosphere. The resulting mixture was stirred at -20 °C for 4 h under nitrogen atmosphere. The reaction was quenched with water and basified to pH 8 with saturated NaHCCh (aq.). The resulting mixture was extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SO4. After filtration, the filtrate was concentrated under reduced pressure to give 5-[(2R,5S)-5- methylpiperidin-2-yl]-l,3-benzothiazole (152 mg, 90%) as a light green oil. MS ESI calculated for CI₃HI₆N₂S [M+H]⁺, 233.10; found, 233.05. 'H NMR (400 MHz, DMSO- ₆) 8 9.39 (s, 1H), 8.15 - 8.10 (m, 2H), 7.53 (dd, J = 8.2, 1.7 Hz, 1H), 3.87 (dd, J = 11.5, 2.6 Hz, 1H), 3.16 - 3.10 (m, 1H), 2.45 (t, J = 11.5 Hz, 1H), 1.90 - 1.80 (m, 2H), 1.76 - 1.53 (m, 2H), 1.29 - 1.20 (m, 1H), 0.90 (d, J = 6.6 Hz, 3H).

Intermediate A8: 1:1 mixture of 5-((2R,5S)-5-methylpiperidin-2-yl)-2-((S)-l- methylpiperidin-3-yl)benzo[d]thiazole and 5-((2R,5S)-5-methylpiperidin-2-yl)-2-((R)-l- methylpiperidin-3-yl)benzo[d]thiazole

Step 1: 1:1 mixture of (S)-5-chloro-2-(l-methylpiperidin-3-yl)benzo[d]thiazole and (R)-5- chloro-2-(l-methylpiperidin-3-yl)benzo[d]thiazole

[0884] A solution of PPA (25.3 g, 219 mmol) and P2O5 (31.2 g, 219 mmol) was stirred at room temperature for 10 minutes under nitrogen atmosphere. Then 2-amino-4- chlorobenzenethiol (8.77 g, 54.9 mmol) and l-methylpiperidine-3-carboxylic acid (9.44 g, 65.4 mmol) were added to above mixture in one portion at room temperature. The resulting mixture was stirred at 110 °C for 16 h. The resulting mixture was quenched with water. The mixture basified with NaOH (10% aq.) to pH 10. The resulting mixture was extracted with CH2CI2. The combined organic layers were washed with brine, dried over anhydrous Na2SC>4. After filtration, the filtrate was concentrated under reduced pressure. The resulting residue was purified by flash column chromatography with a 120 g silica gel column and eluted with 0-4% MeOH in DCM to afford a 1:1 mixture of (S)-5-chloro-2-(l-methylpiperidin-3- yl)benzo[d]thiazole and (R)-5-chloro-2-(l-methylpiperidin-3-yl)benzo[d]thiazole (4.2 g, 28%) as a yellow oil. MS ESI calculated for C13H15CIN2S [M+H]⁺, 267.06; found, 267.00.

Step 2: 1:1 mixture of (S)-2-(l-methylpiperidin-3-yl)-5-(4,4,5,5-tetramethyl-l,3,2- dioxaborolan-2-yl)benzo[d]thiazole and (R)-2-(l -methylpiperidin-3-yl)-5-(4, 4,5,5- tetramethyl- 1 ,3,2-dioxaborolan-2-yl)benzo[d]thiazole

[0885] To a stirred solution of a 1:1 mixture of (S)-5-chloro-2-(l-methylpiperidin-3- yl)benzo[d]thiazole and (R)-5-chloro-2-(l-methylpiperidin-3-yl)benzo[d]thiazole (2.00 g, 7.49 mmol), AcOK (1.47 g, 14.99 mmol) and BPD (2.09 g, 8.24 mmol) in dioxane (20 mL) were added Pd2(dba)3 (343 mg, 0.37 mmol) and XPhos (714 mg, 1.49 mmol) at 25 °C under nitrogen atmosphere. The resulting mixture was stirred at 90 °C for 16 h under nitrogen atmosphere. The resulting mixture was filtered, the filter cake was washed with 1,4-dioxane. The filtrate was concentrated under reduced pressure. Then HC1 (4M in dioxane) was added to the residue and stirred for 15 minutes. The precipitated solids were collected by filtration and dried under vacuum to afford a 1:1 mixture of (S)-2-(l-methylpiperidin-3-yl)-5-(4, 4,5,5- tetramethyl- 1 ,3,2-dioxaborolan-2-yl)benzo[d]thiazole and (R)-2-(l -methylpiperidin-3-yl)-5- (4,4,5,5-tetramethyl-l,3,2-dioxaborolan-2-yl)benzo[d]thiazole as HC1 salts (3.4 g, crude) as a yellow solid. MS ESI calculated for C19H27BN2O2S [M+H]⁺, 359.19; found, 359.10.

Step 3: 1:1 mixture of tert-butyl (S)-3-methyl-6-(2-((S)-l-methylpiperidin-3- yl)benzo[d]thiazol-5-yl)-3,4-dihydropyridine-l(2H)-carboxylate and tert-butyl (S)-3-methyl- 6-(2-((R)-l-methylpiperidin-3-yl)benzo[d]thiazol-5-yl)-3,4-dihydropyridine-l(2H)- carboxylate

[0886] To a stirred solution of a 1:1 mixture of (S)-2-(l-methylpiperidin-3-yl)-5-(4, 4,5,5- tetramethyl-l,3,2-dioxaborolan-2-yl)benzo[d]thiazole and (R)-2-(l-methylpiperidin-3-yl)-5- (4,4,5,5-tetramethyl-l,3,2-dioxaborolan-2-yl)benzo[d]thiazole (259 mg, 0.72 mmol) and tertbutyl (5S)-5-methyl-2-(trifluoromethanesulfonyloxy)-5,6-dihydro-4H-pyridine-l-carboxylate (28 mg, 0.08 mmol) in dioxane (2.5 mL)/water (0.5 mL) were added K2CO3 (200 mg, 1.44 mmol) and Pd(dppf)Ch (52 mg, 0.07 mmol) at 25 °C under nitrogen atmosphere. The resulting mixture was stirred at 100 °C for 3 h under nitrogen atmosphere. The resulting mixture was quenched with water. The resulting mixture was extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SC>4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by flash column chromatography with a 25 g silica gel column and eluted with 0-10% MeOH in DCM to afford a 1:1 mixture of tert-butyl (S)-3-methyl-6-(2-((S)-l-methylpiperidin-3- yl)benzo[d]thiazol-5-yl)-3,4-dihydropyridine-l(2H)-carboxylate and tert-butyl (S)-3-methyl- 6-(2-((R)-l-methylpiperidin-3-yl)benzo[d]thiazol-5-yl)-3,4-dihydropyridine-l(2H)- carboxylate (130 mg, 36%) as a brown oil. MS ESI calculated for C24H33N3O2S [M+H]⁺, 428.23; found, 428.20.

Step-4: 1:1 mixture of 5-((2R,5S)-5-methylpiperidin-2-yl)-2-((S)-l-methylpiperidin-3- yl)benzo[d]thiazole and 5-((2R,5S)-5-methylpiperidin-2-yl)-2-((R)- 1 -methylpiperidin-3- yl)benzo[d]thiazole (A8)

[0887] To a solution of tert-butyl (5S)-5-methyl-2-[2-(l-methylpiperidin-3-yl)-l,3- benzothiazol-5-yl]-5,6-dihydro-4H-pyridine-l -carboxylate (1.00 g, 2.34 mmol) in DCM (8 mL) was added TFA (2 mL). The mixture was stirred at room temperature for 1 h. The resulting mixture was concentrated under vacuum. The residue was dissolved in MeOH (9 mL) and cooled to -20 °C, NaBFL (519 mg, 13.74 mmol) was added in portions. After stirring at -20 °C for 1 h, the reaction was quenched with water. The resulting mixture was extracted with EtOAc. The organic layer was dried over anhydrous Na2SC>4. After filtration, the filtrate was concentrated under reduced pressure to afford a 1:1 mixture of 5-((2R,5S)-5- methylpiperidin-2-yl)-2-((S)-l-methylpiperidin-3-yl)benzo[d]thiazole and 5-((2R,5S)-5- methylpiperidin-2-yl)-2-((R)-l-methylpiperidin-3-yl)benzo[d]thiazole (900 mg, 77%) as a brown oil. MS ESI calculated for C19H27N3S [M+H]⁺, 310.19; found, 310.10. ¹H NMR (400 MHz, DMSO-J₆) 8 (ppm) 8.02 - 7.90 (m, 2H), 7.45 (dd, J= 8.4, 1.6 Hz, 1H), 3.78 (dd, J = 11.4, 2.4 Hz, 1H), 3.35 - 3.31 (m, 1H), 3.17 - 2.95 (m, 2H), 2.67 - 2.65 (m, 1H), 2.42 (t, J = 11.4 Hz, 1H), 2.29 - 2.25 (m, 1H), 2.23 (s, 3H), 2.10 - 2.01 (m, 2H), 1.88 - 1.46 (m, 9H), 0.88 (d, J = 6.6 Hz, 3H).

Intermediate A9: 1:1 mixture of (3R,4aS,10bR)-3-methyl-8-(trifluoromethyl)-

1 ,3, 4, 4a, 5, 10b-hexahydro-2H-chromeno[4,3-b]pyridine and (3S,4aR, 10bS)-3-methyl-8-

(trifluoromethyl)-l,3,4,4a,5,10b-hexahydro-2H-chromeno[4,3-b]pyridine Step 1 : methyl 2-chloro-5-methylpyridine-3-carboxylate

C l^⁰ ^N^CI

[0888] To a stirred solution of 2-chloro-5-methylpyridine-3-carboxylic acid (19.12 g, 111.44 mmol) and Mel (47.45 g, 334.31 mmol) in DMF (200 mL) was added K2CO3 (46.20 g, 334.31 mmol) at 25 °C. The resulting mixture was stirred at 60 °C for 16 h. The resulting mixture was quenched with water and extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SC>4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-20% ethyl acetate in petroleum ether to afford methyl 2- chloro-5-methylpyridine-3-carboxylate (14.60 g, 70%) as a yellow solid. MS ESI calculated for C₈H₈C1NO₂ [M+H]⁺, 186.02; found, 186.10.

Step 2: methyl 2-[2-methoxy-4-(trifluoromethyl)phenyl]-5-methylpyridine-3-carboxylate

[0889] A degassed mixture of methyl 2-chloro-5-methylpyridine-3-carboxylate (10.1 g, 53.9 mmol), 2-methoxy-4-(trifhioromethyl)phenylboronic acid (14.2 g, 64.7 mmol), Pd(dppf)C12-CH₂Cl₂ (4.39 g, 5.39 mmol) and K2CO3 (14.8 g, 107 mmol) in 1, 4-dioxane (100 mL) and H2O (10 mL) was stirred at 100 °C for 3 h under nitrogen atmosphere. The reaction mixture was quenched by the addition of water and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under vacuum. The resulting residue was purified by Combi Flash with a 120 g silica gel column and eluted with 0-50% ethyl acetate in petroleum ether to afford methyl 2- [2-methoxy-4-(trifhioromethyl)phenyl]-5-methylpyridine-3-carboxylate (14.71 g, 83%) as a yellow solid. MS ESI calculated for C16H14F3NO3 [M+H]⁺, 326.09; found, 326.15.

Step 3: 3-methyl-8-(trifluoromethyl)chromeno[4,3-b]pyridin-5-one

[0890] To a solution of methyl 2-[2-methoxy-4-(trifluoromethyl)phenyl]-5-methylpyridine- 3-carboxylate (14.7 g, 45.2 mmol) in DCM (150 mL) was added BB (158 mL, 158 mmol) (1 M in DCM) dropwise at 0 °C. The resulting mixture was stirred at 25 °C for 16 h. The reaction was quenched with water at 0 °C. The resulting mixture was extracted with DCM. The combined organic layers were washed with brine, dried over anhydrous Na2SO4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-50% ethyl acetate in petroleum ether to afford 3-methyl-8-(trifhioromethyl)chromeno[4,3-b]pyridin-5-one (9.55 g, 75%) as a yellow solid. MS ESI calculated for C14H8F3NO2 [M+H]⁺, 280.05; found, 280.00.

Step 4: 3-methyl-8-(trifhioromethyl)-5H-chromeno[4,3-b]pyridine

[0891] To a stirred solution of 3-methyl-8-(trifhioromethyl)chromeno[4,3-b]pyridin-5-one (8.55 g, 30.6 mmol) and NH3-BH3 (1.89 g, 61.22 mmol) in Et2O (160 mL) was added TiCLi (6.7 mL, 61.2 mmol) dropwise at 0 °C. The resulting mixture was stirred at 25 °C for 16 h. The reaction mixture was quenched by the addition of ice water and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under vacuum. The resulting residue was purified by normal phase flash column chromatography with a 120 g silica gel column and eluted with 0- 30% ethyl acetate in dichloromethane within 35 min to afford 3-methyl-8-(trifluoromethyl)- 5H-chromeno[4,3-b]pyridine (4.1 g, 38%) as a yellow solid. MS ESI calculated for C14H10F3NO [M+H]⁺, 266.07; found, 266.15.

Step 5: 1:1 mixture of (3R,4aS,10bR)-3-methyl-8-(trifluoromethyl)-l,3,4,4a,5,10b- hexahydro-2H-chromeno[4,3-b]pyridine and (3S,4aR,10bS)-3-methyl-8-(trifluoromethyl)- l,3,4,4a,5,10b-hexahydro-2H-chromeno[4,3-b]pyridine

[0892] A solution of 3-methyl-8-(trifluoromethyl)-5H-chromeno[4,3-b]pyridine (5.00 g, 18.9 mmol) in 2-Propanol (100 mL) was placed in an autoclave, then Rh/C (3 .01 g, 5% active on carbon) was added to above mixture. The mixture was stirred at 50 °C for 16 h under hydrogen atmosphere (50 atm.). The suspension was filtered. The filtrate was collected and concentrated under vacuum. The resulting residue was purified by Combi Flash with a 120 g C18 column and eluted with 5-100% acetonitrile in water (20 mM NH4HCO3) to afford a 1:1 mixture of (3R,4aS,10bR)-3-methyl-8-(trifluoromethyl)-l,3,4,4a,5,10b-hexahydro-2H- chromeno[4,3-b]pyridine and (3S,4aR,10bS)-3-methyl-8-(trifluoromethyl)-l,3,4,4a,5,10b- hexahydro-2H-chromeno[4,3-b]pyridine (1.80 g, 36%) as a yellow solid. MS ESI calculated for C14H16F3NO [M+H]⁺, 272.12; found, 272.15. 'H NMR (400 MHz, DMSO- fe) 8 7.76 (d, J = 8.0 Hz, 1H), 7.22 (dd, J= 8.2, 2.0 Hz, 1H), 7.02 (d, J= 1.8 Hz, 1H), 4.24 (dd, J = 11.2, 2.2 Hz, 1H), 4.18 (d, J = 5.4 Hz, 1H), 4.08 (dd, J = 11.2, 2.2 Hz, 1H), 2.60 - 2.53 (m, 1H), 2.10 - 1.98 (m, 1H), 1.78 - 1.69 (m, 1H), 1.69 - 1.62 (m, 1H), 1.61 - 1.49 (m, 1H), 0.95 - 0.93 (m, 1H), 0.69 (d, J = 6.4 Hz, 3H).

Intermediate A10: 1:1 mixture of (4aS,9bS)-7-(trifluoromethyl)-l,2,3,4,4a,9b- hexahydrobenzofuro[3,2-b]pyridine and (4aR,9bR)-7-(trifluoromethyl)-l,2,3,4,4a,9b- hexahydrobenzofuro[3,2-b]pyridine

Step 1 : 2-[2-fluoro-4-(trifluoromethyl)phenyl]-3-(methoxymethoxy)pyridine

[0893] To a stirred solution of 2-fluoro-4-(trifluoromethyl)phenylboronic acid (5.00 g, 24.0 mmol) and 2-bromo-3-(methoxymethoxy)pyridine (5.24 g, 24.0 mmol) in 1,4-dioxane (40 mL) and H2O (4 mL) were added PPh3 (3.15 g, 12.0 mmol), K2CO3 (6.65 g, 48.1 mmol) and Pd(OAc)2 (0.54 g, 2.40 mmol) at room temperature under nitrogen atmosphere. The resulting mixture was stirred at 90 °C for 16 h under nitrogen atmosphere. The resulting mixture was concentrated under vacuum. The resulting residue was dissolved in DCM and purified by Combi Flash (Biotage Isolera Prime) which applied to a 120 g silica gel column that was eluted with 0 - 50% ethyl acetate in petroleum ether within 35 min to afford 2-[2-fluoro-4- (trifhioromethyl)phenyl]-3-(methoxymethoxy)pyridine (3.70 g, 45%) as a yellow oil. MS (ESI) calculated for (C14H11F4NO2) [M+H]⁺, 302.07; found, 302.15.

Step-2: Synthesis of 2-[2-fhioro-4-(trifhioromethyl)phenyl]pyridin-3-ol

[0894] To a stirred solution of 2-[2-fhioro-4-(trifluoromethyl)phenyl]-3- (methoxymethoxy)pyridine (4.01 g, 13.3 mmol) in DCM (40 mL) was added TFA (20 mL) at room temperature. The resulting mixture was stirred at room temperature for 16 h. The resulting mixture was concentrated under vacuum to afford 2-[2-fluoro-4- (trifhioromethyl)phenyl]pyridin-3-ol (7.20 g, crude) as a yellow oil. MS (ESI) calculated for (C12H7F4NO) [M+H]⁺, 258.05; found, 257.95.

Step 3: 7-(trifhioromethyl)benzofuro[3,2-b]pyridine

[0895] To a stirred solution of 2-[2-fluoro-4-(trifluoromethyl)phenyl]pyridin-3-ol (7.20 g, 28.0 mmol) in DMF (40 mL) was added K2CO3 (11.61 g, 84.0 mmol) at room temperature under nitrogen atmosphere. The resulting mixture was stirred at 120 °C for 16 h under nitrogen atmosphere. The resulting mixture was cooled down to room temperature. The resulting mixture was diluted with water and extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SC>4. After filtration, the filtrate was concentrated under vacuum to afford 7-(trifhioromethyl)benzofuro[3,2-b]pyridine (6.10 g, 84%) as a brown solid. MS (ESI) calculated for (C12H6F3NO) [M+H]⁺, 238.04; found, 238.15.

Step 4: 1:1 mixture of (4aS,9bS)-7-(trifluoromethyl)-l,2,3,4,4a,9b-hexahydrobenzofuro[3,2- b]pyridine and (4aR,9bR)-7-(trifhioromethyl)-l ,2,3,4,4a,9b-hexahydrobenzofuro[3,2- b]pyridine

[0896] To a solution of 7-(trifhioromethyl)benzofuro[3,2-b]pyridine(3.00 g, 12.6 mmol) in i-PrOH (150 mL) was added Pd(OH)2/C (100 mg) under nitrogen. The mixture was stirred at 50 °C for 16 h under hydrogen atmosphere (50 atm.). The resulting mixture was filtered, the filter cake was washed with i-PrOH (150 mL). The filtrate was collected and concentrated under vacuum. The resulting residue was dissolved in DMF (2 mL) which was applied to a 120 g C18 column and purified by Combi Flash (Biotage Isolera Prime), eluted with 5-50% acetonitrile in water (10 mM NH4HCO3) within 30 min to afford a 1:1 mixture of (4aS,9bS)- 7-(trifluoromethyl)-l,2,3,4,4a,9b-hexahydrobenzofuro[3,2-b]pyridine and (4aR,9bR)-7- (trifhioromethyl)-l,2,3,4,4a,9b-hexahydrobenzofuro[3,2-b]pyridine (240 mg, 7%) as a white solid. MS ESI calculated for (C12H12F3NO) [M+H]⁺, 244.09; found, 244.20. 'H NMR (400 MHz, DMSO-tfe) 8 7.48 (d, 7= 7.6 Hz, 1H), 7.22 (d, 7= 7.6 Hz, 1H), 7.13 (s, 1H), 4.54 (q, J = 4.8 Hz, 1H), 4.29 (d, J = 6.0 Hz, 1H), 2.66 - 2.56 (m, 2H), 2.33 (br, 1H), 2.06 - 1.86 (m, 2H), 1.52 - 1.35 (m, 2H).

Intermediate A10 isomer 1: rel-(4aS,9bS)-7-(trifluoromethyl)-l,2,3,4,4a,9b- hexahydrobenzofuro[3,2-b]pyridine isomer 1 and,

Intermediate A10 isomer 2: rel-(4aS,9bS)-7-(trifluoromethyl)-l,2,3,4,4a,9b- hexahydrobenzofuro[3,2-b]pyridine isomer 2

A10 isomer 2

[0897] Intermediate A10 (200 mg) was separated by prep-chiral HPLC with the following conditions: [Column: CHIRALPAK IF, 2*25 cm, 5 pm; Mobile Phase A: Hex(0.5% 2M NHs-MeOH)— HPLC, Mobile Phase B: EtOH— HPLC; Flow rate: 20 mL/min; Gradient: 2% B to 2% B in 15 min; Wave Length: 220/254 nm; RTl(min): 5.55; RT2(min): 6.24; Sample Solvent: EtOH: Hex=l: 1— HPLC; Injection Volume: 0.55 mL; Number Of Runs: 8] to afford rel-(4aS,9bS)-7-(trifluoromethyl)-l,2,3,4,4a,9b-hexahydrobenzofuro[3,2-b]pyridine isomer 1 (A10 isomer 1) (22.6 mg) as a white solid with the first peak on chiral-HPLC. MS ESI calculated for (C12H12F3NO) [M+H]⁺, 244.09; found, 244.20. 'H NMR (400 MHz, DMSO- d₆) 5 7.47 (d, J = 7.6 Hz, 1H), 7.22 (d, J = 7.6 Hz, 1H), 7.13 (s, 1H), 4.54 (q, J = 4.8 Hz, 1H), 4.29 (d, J= 6.0 Hz, 1H), 2.66 - 2.56 (m, 2H), 2.33 (s, 1H), 2.06 - 1.87 (m, 2H), 1.51 - 1.35 (m, 2H). Absolute stereochemistry was not determined.

[0898] The chiral resolution also afforded rel-(4aS,9bS)-7-(trifluoromethyl)-l,2,3,4,4a,9b- hexahydrobenzofuro[3,2-b]pyridine isomer 2 (A10 isomer 2) (19.7 mg) as a white solid with the second peak on chiral-HPLC. MS ESI calculated for (C12H12F3NO) [M+H]⁺, 244.09; found, 244.20. 'H NMR (400 MHz, DMSO- fe) 8 7.47 (d, J= 7.6 Hz, 1H), 7.22 (d, J= 7.6 Hz, 1H), 7.13 (s, 1H), 4.54 (q, J = 4.8 Hz, 1H), 4.29 (d, J = 6.0 Hz, 1H), 2.66 - 2.56 (m, 2H), 2.33 (s, 1H), 2.06 - 1.87 (m, 2H), 1.51 - 1.35 (m, 2H). Absolute stereochemistry was not determined.

Intermediate All: 1:1 mixture of (4aS,9bS)-7-(difluoromethoxy)-l,2,3,4,4a,9b- hexahydrobenzofuro[3,2-b]pyridine and (4aR,9bR)-7-(difluoromethoxy)- 1 , 2, 3, 4, 4a, 9b- hexahydrobenzofuro[3,2-b]pyridine

Step 1: Synthesis of l-bromo-4-(difluoromethoxy)-2-fluorobenzene

[0899] To a stirred solution of 4-bromo-3-fluorophenol (10 g, 52.36 mmol) in MeCN (500 mL) was added a solution of KOH (29.37 g, 523.56 mmol) in H2O (120 mL) at room temperature. To the above mixture was added diethyl bromodifhioromethylphosphonate (55.92 g, 209.42 mmol) at room temperature. The resulting mixture was stirred at 30 °C for 16 h. The reaction mixture was quenched by the addition of water and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under vacuum. The resulting residue was purified by normal phase flash chromatography which applied to 120 g silica gel column and eluted with 0-10% ethyl acetate in petroleum ether within 35 min to afford l-bromo-4- (difluoromethoxy)-2-fluorobenzene (9.3 g, 72%) as a colorless oil. ¹H NMR (400 MHz, DMSO-d₆) 8 7.83 - 7.69 (m, 1H), 7.54 - 7.11 (m, 2H), 7.06 - 7.02 (m, 1H).

Step 2: 2-[4-(difluoromethoxy)-2-fluorophenyl]-4,4,5,5-tetramethyl-l,3,2-dioxaborolane

[0900] To a stirred solution of l-bromo-4-(difluoromethoxy)-2-fluorobenzene (9.30 g, 38.59 mmol) and BPD (9.80 g, 38.59 mmol) in 1,4-dioxane (100 mL) were added AcOK (11.36 g, 115.75 mmol) and Pd(dppp)Ch (2.28 g, 3.86 mmol) at room temperature under nitrogen atmosphere. The resulting mixture was stirred at 80 °C for 16 h under nitrogen atmosphere. The reaction mixture was quenched by the addition of water and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under vacuum. The resulting residue was purified by normal phase flash chromatography which applied to 330 g silica gel column and eluted with 0-10% ethyl acetate in petroleum ether within 35 min to afford 2-[4-(difluoromethoxy)- 2-fluorophenyl]-4,4,5,5-tetramethyl-l,3,2-dioxaborolane (8 g, 71 %) as a yellow solid. 'H NMR (400 MHz, DMSO-d₆) 8 7.73 - 7.65 (m, 1H), 7.54 - 7.15 (m, 1H), 7.07 - 7.02 (m, 2H), 1.44 - 1.18 (m, 12H).

Step 3 : 2- [4-(difluoromethoxy)-2-fhiorophenyl]-3-(methoxymethoxy)pyridine

[0901] To a stirred solution of 2-[4-(difhioromethoxy)-2-fluorophenyl]-4,4,5,5-tetramethyl- 1,3,2-dioxaborolane (8 g, 27.78 mmol) and 2-bromo-3-(methoxymethoxy)pyridine (6.06 g, 27.78 mmol) in 1,4-dioxane (30 mL) and H2O (6 mL) were added NaiCOs (5.89 g, 55.54 mmol) and Pd(PPh3)4 (3.21 g, 2.78 mmol) at room temperature under nitrogen atmosphere. The resulting mixture was stirred at 90 °C for 16 h under nitrogen atmosphere. The reaction mixture was quenched by the addition of water and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under vacuum. The resulting residue was purified by normal phase flash chromatography which applied to 120 g silica gel column and eluted with 0-30% ethyl acetate in petroleum ether within 40 min to afford 2-[4-(difluoromethoxy)-2-fluorophenyl]-3- (methoxymethoxy)pyridine (7.3 g, 86%) as a yellow oil. MS ESI calc’d for C14H12F3NO3 [M+H]⁺, 300.08; found, 300.10.

Step 4: Synthesis of 2-[4-(difluoromethoxy)-2-fluorophenyl]pyridin-3-ol

[0902] A solution of 2-[4-(difluoromethoxy)-2-fluorophenyl]-3-(methoxymethoxy)pyridine (7.30 g, 24.39 mmol) and TFA (35 mL) in DCM (70 mL) was stirred at room temperature for 16 h. The resulting mixture was concentrated under reduced pressure to afford 2- [4- (difluoromethoxy)-2-fluorophenyl]pyridin-3-ol (11 g, crude) as a brown oil. MS ESI calc’d for C12H8F3NO2 [M+H]⁺, 256.05; found, 256.05.

Step 5: 7-(difluoromethoxy)benzofuro[3,2-b]pyridine

[0903] To a stirred solution of 2-[4-(difluoromethoxy)-2-fluorophenyl]pyridin-3-ol (11 g, 43.1 mmol) in DMF (150 mL) was added K2CO3 (29.8 g, 215.52 mmol) at room temperature. The resulting mixture was stirred at 120 °C for 2 h. The reaction mixture was quenched by the addition of water and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under vacuum to afford 7-(difluoromethoxy)benzofuro[3,2-b]pyridine (5.3 g, crude) as a yellow solid. MS ESI calc’d for (Ci2H₇F₂NO2) [M+H]⁺, 236.04; found, 235.95. Step 6: 1:1 mixture of (4aS,9bS)-7-(difluoromethoxy)-l,2,3,4,4a,9b-hexahydrobenzofuro[3,2- b]pyridine and (4aR,9bR)-7-(difluoromethoxy)-l,2,3,4,4a,9b-hexahydrobenzofuro[3,2- b]pyridine

[0904] To a stirred solution of 7-(difluoromethoxy)benzofuro[3,2-b]pyridine (5 g, 21.3 mmol) and tris(2,3,4,5,6-pentafluorophenyl)borane (1.09 g, 2.13 mmol) in Toluene (50 mL) were added 4,4,5,5-tetramethyl-l,3,2-dioxaborolane (13.60 g, 106.30 mmol) and N- phenylaniline (14.4 g, 85.0 mmol) at room temperature. The resulting mixture was stirred at 110 °C for 16 h. The mixture was acidified to pH - 10 with saturated NaHCCh (aq.). The resulting mixture was extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous NazSC After filtration, the filtrate was concentrated under reduced pressure. The resulting residue was purified by normal phase flash chromatography which applied to 120 g silica gel column and eluted with 0-15% methanol in dichloromethane within 30 min to afford a 1:1 mixture of (4aS,9bS)-7-(difluoromethoxy)-l,2,3,4,4a,9b- hexahydrobenzofuro[3,2-b]pyridine and (4aR,9bR)-7-(difluoromethoxy)-l,2,3,4,4a,9b- hexahydrobenzofuro[3,2-b]pyridine (4.5 g, 70%) as a yellow oil. MS ESI calculated for C12H13F2NO2 [M+H]⁺, 242.09; found, 242.15. 'H NMR (400 MHz, DMSO-de) 3 7.41 - 6.95 (m, 2H), 6.66 (d, J = 6.8 Hz, 2H), 4.50 - 4.45 (m, 1H), 4.19 (d, J = 5.8 Hz, 1H), 2.68 - 2.59 (m, 1H), 2.65 - 2.54 (m, 1H), 2.00 - 1.89 (m, 2H), 1.53 - 1.33 (m, 2H).

Intermediate A12: 1:1 mixture of (4aR,9bR)-7-(difluoromethoxy)-2,3,4,4a,5,9b-hexahydro- lH-indeno[l ,2-b]pyridine and (4aS,9bS)-7-(difluoromethoxy)-2,3,4,4a,5,9b-hexahydro- 1H- indeno[l ,2-b]pyridine

Step 1: {2-[4-(difluoromethoxy)phenyl]pyridin-3-yl}methanol

[0905] To a stirred solution of 4-(difluoromethoxy)phenylboronic acid (3.00 g, 15.96 mmol) and (2-chloropyridin-3-yl)methanol (2.75 g, 19.15 mmol) in dioxane (30 mL) were added Na2CC>3 (5.08 g, 47.88 mmol) and Pd(PPh3)4 (1.84 g, 1.59 mmol) at room temperature under nitrogen atmosphere. The resulting mixture was stirred at 90 °C for 2 h under nitrogen atmosphere. The residue was quenched with water. The resulting mixture was extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SC>4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-30% ethyl acetate in petroleum ether within 30 min to afford (2-[4-(difhioromethoxy)phenyl]pyridin-3-yl)methanol (3.5 g, 86%) as a yellow oil. MS ESI calculated for C13H11F2NO2 [M+H]⁺, 252.08; found, 252.10.

Step 2: 3-(chloromethyl)-2-[4-(difhioromethoxy)phenyl]pyridine

[0906] A solution of {2-[4-(difluoromethoxy)phenyl]pyridin-3-yl}methanol (3.50 g, 13.93 mmol) and SOCI2 (2.49 g, 20.89 mmol) in DCM (35 mL) was stirred at room temperature for 2 h. The resulting mixture was concentrated under reduced pressure to afford 3- (chloromethyl)-2-[4-(difluoromethoxy)phenyl]pyridine (4.0 g, crude) as a yellow solid. MS ESI calculated for C13H10CIF2NO [M+H]⁺, 270.04, 272.04; found, 270.05, 272.05.

Step 3: 7-(difluoromethoxy)-5H-indeno[l,2-b]pyridine

[0907] To a stirred solution of 3-(chloromethyl)-2-[4-(difluoromethoxy)phenyl]pyridine (4.00 g, 14.83 mmol) and Na2CC>3 (6.29 g, 59.32 mmol) in DME (40 mL) were added Pd(OAc)2 (0.33 g, 1.48 mmol) and P(m-Tol)3 (0.90 g, 2.96 mmol) at room temperature under nitrogen atmosphere. The resulting mixture was stirred at 110°C for 2 h under nitrogen atmosphere. The resulting mixture was quenched with water and extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SC>4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-40% ethyl acetate in petroleum ether within 30 min to afford 7-(difluoromethoxy)-5H-indeno[l,2-b]pyridine (2.7 g, 77%) as a light brown solid. MS ESI calculated for C13H9F2NO [M+H]⁺, 234.07; found, 234.10.

Step 4: 1:1 mixture of (4aR,9bR)-7-(difluoromethoxy)-2,3,4,4a,5,9b-hexahydro-lH- indeno[l ,2-b]pyridine and (4aS,9bS)-7-(difluoromethoxy)-2,3,4,4a,5,9b-hexahydro- 1H- indeno[l ,2-b]pyridine

[0908] To a stirred solution of 7-(difluoromethoxy)-5H-indeno[l,2-b]pyridine (2.20 g, 9.43 mmol) and tris(2,3,4,5,6-pentafluorophenyl)borane (0.48 g, 0.94 mmol) in Toluene (44 mL) were added N-phenylaniline (6.38 g, 37.73 mmol) and 4,4,5,5-tetramethyl-l,3,2- dioxaborolane (6.03 g, 47.16 mmol) at room temperature. The resulting mixture was stirred at 110°C for 16 h. The resulting mixture was concentrated under vacuum. The resulting residue was dissolved in MeCN which was applied to a 80 g C 18 column and purified by Combi Flash, eluted with 5-50% acetonitrile in water (10 mM NH4HCO3) within 30 min to afford a 1:1 mixture of (4aR,9bR)-7-(difluoromethoxy)-2,3,4,4a,5,9b-hexahydro-lH-indeno[l,2- b]pyridine and (4aS,9bS)-7-(difluoromethoxy)-2,3,4,4a,5,9b-hexahydro-lH-indeno[l,2- b]pyridine (1.3 g, 54%) as a brown oil. MS ESI calculated for C13H15F2NO [M+H]⁺, 240.11; found, 240.10. 'H NMR (400 MHz, DMSO-J₆) 87.40 - 7.27 (m, 1H), 7.18 - 6.92 (m, 3H), 4.15 (d, J = 5.6 Hz, 1H), 2.86 - 2.73 (m, 1H), 2.68 - 2.55 (m, 2H), 2.49 - 2.40 (m, 1H), 2.39 - 2.23 (m, 1H), 1.76 - 1.58 (m, 1H), 1.51 - 1.31 (m, 2H), 1.31 - 1.15 (m, 1H).

Intermediate A13: 1:1 mixture of (4aS,9aR)-7-(difluoromethoxy)-2,3,4,4a,9,9a- hexahydroindeno[2,l-b][l,4]oxazine and (4aR,9aS)-7-(difluoromethoxy)-2,3,4,4a,9,9a- hexahydroindeno [2, 1 -b] [ 1 ,4]oxazine

Step 1: 5-(difluoromethoxy)-2,3-dihydroinden-l-one

[0909] To a stirred solution of 5-hydroxy-2,3-dihydroinden-l-one (25.00 g, 168.73 mmol) and KOH (56.80 g, 1012.41 mmol) in DCM (250 mL)/water (150 mL) was added (bromodifluoromethyl)trimethylsilane (68.54 g, 337.47 mmol) dropwise at 0 °C under nitrogen atmosphere. The resulting mixture was stirred at 0 °C for 2 h under nitrogen atmosphere. The reaction mixture was extracted with DCM. The combined organic layers were washed with brine, dried over anhydrous Na2SO4. After filtration, the filtrate was concentrated under reduced pressure. The resulting residue was purified by normal phase flash column chromatography with a 330 g silica gel column and eluted with 0-30% ethyl acetate in petroleum ether to 5-(difluoromethoxy)-2,3-dihydroinden-l-one) as a yellow oil. MS ESI calculated for C10H8F2O2 [M+H]⁺, 199.05; found, 199.10.

Step 2: 1:1 mixture of (R)-2-bromo-5-(difluoromethoxy)-2,3-dihydroinden-l-one and (S)-2- bromo-5-(difluoromethoxy)-2,3-dihydroinden- 1 -one

[0910] To a mixture of 5-(difhioromethoxy)-2,3-dihydroinden-l-one (2.00 g, 10.09 mmol) in EtOAc (20 mL) was added CuBr₂ (4.51 g, 20.18 mmol). The mixture was stirred at 80 °C for 16 h. The reaction mixture was filtered. The filtrate was collected and concentrated under vacuum. The resulting residue was purified by normal phase flash column chromatography with 0-40% ethyl acetate in petroleum ether to afford a 1:1 mixture of (R)-2-bromo-5- (difhioromethoxy)-2,3-dihydroinden- 1 -one and (S)-2-bromo-5-(difluoromethoxy)-2,3- dihydroinden-l-one (1.80 g, 63%) as a yellow oil. MS ESI calculated for CioH/BrFiCh [M+H]⁺, 276.96, 278.96; found, 276.90, 278.90.

Step 3: 1:1 mixture of (lS,2R)-2-bromo-5-(difhioromethoxy)-2,3-dihydro-lH-inden-l-ol and ( 1 R,2S)-2-bromo-5-(difluoromethoxy)-2,3-dihydro- 1 H-inden- 1 -ol

[0911] To a stirred solution of a 1:1 mixture of (R)-2-bromo-5-(difluoromethoxy)-2,3- dihydroinden-l-one and (S)-2-bromo-5-(difhioromethoxy)-2,3-dihydroinden-l-one (1.80 g, 6.49 mmol) in EtOH (20 mL) was added NaBtL (0.12 g, 3.24 mmol) in portions at room temperature. The resulting mixture was stirred at room temperature for 1 h. The reaction mixture was quenched by water and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under vacuum to afford a 1:1 mixture of (lS,2R)-2-bromo-5-(difluoromethoxy)- 2,3-dihydro-lH-inden-l-ol and (lR,2S)-2-bromo-5-(difluoromethoxy)-2,3-dihydro-lH- inden-l-ol (1.80 g, 86%) as a yellow solid. MS ESI calculated for CioH9BrF202 [M+H]⁺, 278.98, 280.98; found, 278.95, 280.95.

Step 4: 1 :1 mixture of (lS,2R)-l-amino-5-(difluoromethoxy)-2,3-dihydro-lH-inden-2-ol and (lR,2S)-l-amino-5-(difluoromethoxy)-2,3-dihydro-lH-inden-2-ol

[0912] To a stirred solution of a 1:1 mixture of (lS,2R)-2-bromo-5-(difluoromethoxy)-2,3- dihydro- lH-inden- 1 -ol and (lR,2S)-2-bromo-5-(difluoromethoxy)-2,3-dihydro- lH-inden- 1 - ol (11.12 g, 39.84 mmol) and MeCN (4.91 g, 119.53 mmol) in DCE (120 mL) was added H2SO4 (5.86 g, 59.8 mmol) dropwise at room temperature. The resulting mixture was stirred at 50 °C for 2 h. The reaction mixture was separated. The aqueous solution was basified with NaOH (sat.) to pH -12 and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under vacuum to afford a 1:1 mixture of (1 S,2R)-1-amino-5-(difluoromethoxy)-2,3-dihydro-lH- inden-2-ol and (lR,2S)-l-amino-5-(difluoromethoxy)-2,3-dihydro-lH-inden-2-ol (3.60 g, 29%) as a yellow solid. MS ESI calculated for C10H11F2NO2 [M+H]⁺, 216.08; found, 216.10.

Step 5: 1:1 mixture of (4aR,9aS)-7-(difhioromethoxy)-4,4a,9,9a-tetrahydroindeno[2,l- b] [ 1 ,4] oxazin-3 (2H)-one and (4aS ,9aR)-7 -(difhioromethoxy)-4,4a,9,9a-tetrahydroindeno[2, 1 - b] [1 ,4]oxazin-3(2H)-one

[0913] To a stirred suspension of a 1:1 mixture of (lS,2R)-l-amino-5-(difhioromethoxy)- 2,3-dihydro-lH-inden-2-ol and (lR,2S)-l-amino-5-(difluoromethoxy)-2,3-dihydro-lH-inden-

2- (3.40 g, 15.79 mmol) and CS2CO3 (10.30 g, 31.59 mmol) in MeCN (35 mL) was added 2- chloroacetyl chloride (1.82 g, 16.11 mmol) dropwise at 0 °C. The resulting mixture was stirred at room temperature for 1 h. The reaction mixture was quenched by water and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under vacuum. The residue was dissolved in THF (35 mL) and cooled to 0 °C, then NaH (0.75 g, 18.75 mmol, 60% in mineral oil) was added in portions with stirring. The mixture was stirred at 25 °C for 1 h. The reaction mixture was quenched by water and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under vacuum to afford a 1 : 1 mixture of (4aR,9aS)-7-(difhioromethoxy)- 4,4a,9,9a-tetrahydroindeno[2,l-b][l,4]oxazin-3(2H)-one and (4aS,9aR)-7-(difluoromethoxy)- 4,4a,9,9a-tetrahydroindeno[2,l-b][l,4]oxazin-3(2H)-one (4.10 g, 86%) as a yellow solid. MS ESI calculated for C12H11F2NO3 [M+H]⁺, 256.07; found, 256.15.

Step 6: 1:1 mixture of (4aS,9aR)-7-(difhioromethoxy)-2,3,4,4a,9,9a-hexahydroindeno[2,l- b] [1 ,4]oxazine and (4aR,9aS)-7-(difluoromethoxy)-2,3,4,4a,9,9a-hexahydroindeno[2, 1- b][ 1,4] oxazine

[0914] To a stirred mixture of NaB U (1.78 g, 47.13 mmol) in THF (40 mL) was added BFs-Et2O (6.69 g, 47.13 mmol) dropwise at 0 °C under nitrogen atmosphere. The mixture was stirred at 25 °C for 1 h. Then a 1:1 mixture of (4aR,9aS)-7-(difhioromethoxy)-4,4a,9,9a- tetrahydroindeno[2, 1-b] [1 ,4]oxazin-3(2H)-one and (4aS,9aR)-7-(difluoromethoxy)-4,4a,9,9a- tetrahydroindeno[2,l-b][l,4]oxazin-3(2H)-one (4.01 g, 15.71 mmol) was added at 0 °C. The resulting mixture was stirred at 25 °C. The reaction mixture was quenched by acetone at 0 °C. The suspension was filtered. The filtrate was collected and concentrated under vacuum. The residue was purified by reverse phase flash column chromatography with 5-50% acetonitrile in water (0.1% TFA) to afford a 1:1 mixture of (4aS,9aR)-7-(difhioromethoxy)- 2,3,4,4a,9,9a-hexahydroindeno[2, 1-b] [1 ,4]oxazine and (4aR,9aS)-7-(difluoromethoxy)- 2,3,4,4a,9,9a-hexahydroindeno[2,l-b][l,4]oxazine (760 mg, 16%) as a yellow oil. MS ESI calculated for C12H13F2NO2 [M+H]⁺, 242.09; found, 242.15. Intermediate A14, isomerl: rel-(2R,4aS,10bS)-2-methyl-8-(trifluoromethyl)-2,3,4,4a,6,10b- hexahydro-lH-isochromeno[4,3-b]pyridine, isomer 1:

A14, isomerl . _an(

Intermediate A14, isomerl: rel-(2S,4aR,10bR)-2-methyl-8-(trifluoromethyl)- 2,3,4,4a,6,10b-hexahydro-lH-isochromeno[4,3-b]pyridine, isomer 2:

A14, isomer2

Step 1 : methyl 2-bromo-5-(trifluoromethyl)benzoate

[0915] To a stirred solution of 2-bromo-5-(trifluoromethyl)benzoic acid (100.00 g, 371.72 mmol) and K2CO3 (102.75 g, 743.44 mmol) in DMF (1000 mL) was added Mel (58.04 g, 408.89 mmol) dropwise at 0 °C under nitrogen atmosphere. The resulting mixture was stirred at 25 °C for 4 h under nitrogen atmosphere. The reaction was diluted with water. The resulting mixture was extracted with EtOAc. The combined organic layers were washed with water and brine, dried over anhydrous Na2SC>4. After filtration, the filtrate was concentrated to afford methyl 2-bromo-5-(trifluoromethyl)benzoate (98.40 g, 92%) as a light yellow solid. MS ESI calculated for C-jHeBrFaCh [M+H]⁺, 282.95, 284.04; found, 283.05, 285.00.

Step 2: methyl 2-(4,4,5,5-tetramethyl-l,3,2-dioxaborolan-2-yl)-5-(trifluoromethyl)benzoate

[0916] To a stirred solution of methyl 2-bromo-5-(trifluoromethyl)benzoate (98.40 g, 347.64 mmol) and BPD (97.11 g, 382.41 mmol) in dioxane (980 mL) were added Pd(dppf)Ch (25.44 g, 34.76 mmol) and KOAc (102.36 g, 1042.94 mmol) at room temperature under nitrogen atmosphere. The resulting mixture was stirred at 85 °C for 16 h under nitrogen atmosphere. The resulting mixture was filtered, the filter cake was washed with ethyl acetate. The filtrate was concentrated under reduced pressure. The residue was purified by flash column chromatography with 0-20% ethyl acetate in petroleum ether to afford methyl 2-(4,4,5,5-tetramethyl- l,3,2-dioxaborolan-2-yl)-5-(trifluoromethyl)benzoate (91.00 g, 79%) as a light yellow solid. MS ESI calculated for C15H18BF3O4 [M+H]⁺, 331.13; found, 331.15.

Step 3: methyl 2-(3-fluoro-6-methylpyridin-2-yl)-5-(trifluoromethyl)benzoate

[0917] To a stirred mixture of methyl 2-(4,4,5,5-tetramethyl-l,3,2-dioxaborolan-2-yl)-5- (trifhioromethyl)benzoate (91.00 g, 275.66 mmol) in 1,4-di oxane (910 mL) and water (91 mL) were added 2-bromo-3-fluoro-6-methylpyridine (52.38 g, 275.66 mmol), K2CO3 (113.82 g, 826.98 mmol) and Pd(dppf)Ch (20.17 g, 27.56 mmol). The resulting mixture was stirred at 100 °C for 16 h under nitrogen atmosphere. The resulting mixture was diluted with water. The resulting mixture was extracted with EtOAc. The combined organic layers were washed with water, dried over anhydrous Na2SO4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by flash column chromatography with 0-20% ethyl acetate in petroleum ether to afford methyl 2-(3-fluoro-6-methylpyridin-2-yl)-5- (trifluoromethyl)benzoate (62.40 g, 52%) as a fight yellow oil. MS ESI calculated for C15H11F4NO2 [M+H]⁺, 314.07; found, 314.00.

Step 4: [2-(3-fluoro-6-methylpyridin-2-yl)-5-(trifluoromethyl)phenyl]methanol

[0918] To a stirred mixture of Lithium aluminum hydriden (15.12 g, 398.40 mmol) in THF (500 mL) was added a solution of methyl 2-(3-fluoro-6-methylpyridin-2-yl)-5- (trifhioromethyl)benzoate (62.40 g, 199.20 mmol) in THF (150 mL) dropwise at 0 °C. The resulting mixture was stirred at 0 °C for 2 h. The reaction was quenched by the addition of water (15 mL) and NaOH (aq., 10%) (15 mL) at 0 °C. The resulting mixture was filtered, the filter cake was washed with ethyl acetate. The filtrate was washed with water and brine, dried over anhydrous NajSCL. After filtration, the filtrate was concentrated under reduced pressure to afford [2-(3-fluoro-6-methylpyridin-2-yl)-5-(trifluoromethyl)phenyl]methanol (54 g, 47%) as a light yellow solid. MS ESI calculated for C14H11F4NO [M+H]⁺, 286.08; found, 286.15.

Step 5: 2-methyl-8-(trifluoromethyl)-6H-isochromeno[4,3-b]pyridine

[0919] To a stirred solution of [2-(3-fluoro-6-methylpyridin-2-yl)-5- (trifluoromethyl)phenyl]methanol (54.00 g, 189.31 mmol) in DMF (540 mL) was added t- BuOK (42.49 g, 378.62 mmol) in portions at 0 °C. The resulting mixture was stirred at 25 °C for 3 h. The resulting mixture was diluted with water. The resulting mixture was extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SC>4. After filtration, the filtrate was concentrated under reduced pressure to afford 2- methyl-8-(trifluoromethyl)-6H-isochromeno[4,3-b]pyridine (45.7 g, crude) as a brown solid, which was used directly in next reactions. MS ESI calculated for C14H10F3NO [M+H]⁺, 266.07; found, 266.10.

Step 6: 1:1 mixture of (2R,4aS,10bS)-2-methyl-8-(trifluoromethyl)-2,3,4,4a,6,10b- hexahydro- lH-isochromeno[4,3-b]pyridine and (2S,4aR,10bR)-2-methyl-8-(trifluoromethyl)- 2,3,4,4a,6,10b-hexahydro-lH-isochromeno[4,3-b]pyridine (A14)

[0920] To a stirred solution of 2-methyl-8-(trifhioromethyl)-6H-isochromeno[4,3- b]pyridine (45.00 g, 169.81 mmol) in AcOH (450 mL) was added PtOz (9.00 g, 39.34 mmol) at room temperature. The mixture was hydrogenated at room temperature for 16 h under hydrogen atmosphere. The mixture was filtered through a Celite pad. The filtrate was concentrated under reduced pressure. The residue was dissolved in water and neutralized to pH 7 - 8 with NaHCCh (sat.). The resulting mixture was extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SO4. The residue was purified by silica gel column chromatography, eluted with 0 ~ 20% ethyl acetate in petroleum ether to afford a 1:1 mixture of (2R,4aS,10bS)-2-methyl-8-(trifluoromethyl)- 2,3,4,4a,6,10b-hexahydro-lH-isochromeno[4,3-b]pyridine and (2S,4aR,10bR)-2-methyl-8- (trifhioromethyl)-2,3,4,4a,6,10b-hexahydro-lH-isochromeno[4,3-b]pyridine (12.7 g, 27%) as a fight brown solid. The methyl group has the syn position with the tricyclic by NOE. MS ESI calculated for C14H16F3NO [M+H]⁺, 272.12; found, 272.10. ’H NMR (400 MHz, CD3OD) 3 7.62 - 7.49 (m, 2H), 7.42 (s, 1H), 5.01 (d, J = 15.6 Hz, 1H), 4.84 (d, J = 15.6 Hz, 1H), 3.72 - 3.71 (m, 1H), 3.70 - 3.67 (m, 1H), 2.93 - 2.85 (m, 1H), 2.18 - 2.07 (m, 1H), 1.93 - 1.84 (m, 1H), 1.59 - 1.49 (m, 1H), 1.49 - 1.43 (m, 1H),1.13 (d, J= 6.4 Hz, 3H).

Step 7: rel-(2R,4aS,10bS)-2-methyl-8-(trifluoromethyl)-2,3,4,4a,6,10b-hexahydro-lH- isochromeno[4,3-b]pyridine, isomer 1 (A14, isomer 1):

A14, isomerl . _an(j rel-(2R,4aS, 10bS)-2-methyl-8-(trifluoromethyl)-2,3,4,4a,6, lOb-hexahydro- 1H- isochromeno[4,3-b]pyridine, isomer 2 (A14, isomer 2):

A14, isomer2

[0921] A 1:1 mixture of (2R,4aS,10bS)-2-methyl-8-(trifluoromethyl)-2,3,4,4a,6,10b- hexahydro- lH-isochromeno[4,3-b]pyridine and (2S,4aR, 10bR)-2-methyl-8-(trifluoromethyl)- 2,3,4,4a,6,10b-hexahydro-lH-isochromeno[4,3-b]pyridine (7.4 g) was separated by prep- chiral SFC with the following conditions: [Column: CHIRALPAK IG, 3*25 cm, 5 pm; Mobile Phase A: CO₂, Mobile Phase B: MEOH (0.1% 2M NH3-MEOH); Flow rate: 80 mL/min; Gradient: isocratic 10% B; RTl(min): 5; RT2(min): 6.5; Sample Solvent: MEOH; Injection Volume: 1 mL; Number Of Runs: 100] to afford rel-(2R,4aS,10bS)-2-methyl-8- (trifhioromethyl)-2,3,4,4a,6,10b-hexahydro-lH-isochromeno[4,3-b]pyridine, isomer 1 (A14, isomer 1) (2.85 g, 42%) as a brown oil with the first peak on chiral SFC. MS (ESI) calculated for (C14H16F3NO) [M+H]⁺, 272.12; found, 272.15. 'H NMR (400 MHz, CD3OD) 5 7.61 -

7.49 (m, 2H), 7.42 (s, 1H), 5.01 (d, J = 15.6 Hz, 1H), 4.84 (d, J = 15.6 Hz, 1H), 3.76 - 3.65 (m, 2H), 2.92 - 2.84 (m, 1H), 2.15 - 2.09 (m, 1H), 1.93 - 1.84 (m, 1H), 1.56 - 1.49 (m, 1H),

1.49 - 1.39 (m, 1H), 1.13 (d, J = 6.4 Hz, 3H). Absolute stereochemistry was not determined.

[0922] The chiral separation also afford rel-(2R,4aS,10bS)-2-methyl-8-(trifluoromethyl)- 2,3,4,4a,6,10b-hexahydro-lH-isochromeno[4,3-b]pyridine, isomer 2 (A14, isomer 2) (3.3 g, 49%) as a brown oil with the second peak on chiral SFC. MS (ESI) calculated for (C14H16F3NO) [M+H]⁺, 272.12; found, 272.15. ¹H NMR (400 MHz, CD3OD) 5 7.61 - 7.49 (m, 2H), 7.42 (s, 1H), 5.01 (d, J = 15.6 Hz, 1H), 4.84 (d, J = 15.6 Hz, 1H), 3.75 - 3.66 (m, 2H), 2.92 - 2.84 (m, 1H), 2.14 - 2.09 (m, 1H), 1.93 - 1.84 (m, 1H), 1.58 - 1.49 (m, 1H), 1.49 - 1.40 (m, 1H), 1.13 (d, J= 6.4 Hz, 3H). Absolute stereochemistry was not determined.

Intermediate A15, isomer 1: (3R,4aR,9aS)-7-(difhioromethoxy)-3-methyl-2,3,4,4a,9,9a- hexahydroindeno[2,l-b][l,4]oxazine hydrochloride (A15, isomer 1):

A15, isomer 1 . _an(j

Intermediate A15, isomer 2: (3R,4aS,9aR)-7-(difluoromethoxy)-3-methyl-2,3,4,4a,9,9a- hexahydroindeno[2,l-b][l,4]oxazine hydrochloride (A15, isomer 2):

A15, isomer 2

Step-1 : 5-(difluoromethoxy)-2,3-dihydroinden- 1-one

[0923] To a stirred solution of 5-hydroxy-2,3-dihydroinden-l-one (55.00 g, 371.21 mmol) in DCM (550 mL) was added a solution of KOH (124.96 g, 2227.30 mmol) and H2O (456 mL) at 0 °C under nitrogen atmosphere. Then (bromodifhioromethyl)trimethylsilane (150.79 g, 742.43 mmol) was added to the above mixture dropwise at 0 °C. The resulting mixture was stirred at room temperature for additional 2 h. The reaction mixture was quenched by the addition of Water/Ice at room temperature. The resulting mixture was extracted with CH2CI2. The combined organic layers were washed with brine, dried over anhydrous Na2SO4. After filtration, the filtrate was concentrated under vacuum. The resulting residue was purified by normal phase flash chromatography which applied to 330 g silica gel column and eluted with 0 ~ 30% ethyl acetate in petroleum ether to afford 5-(difhioromethoxy)-2,3-dihydroinden-l- one (52.00 g, 77%) as a light yellow solid. MS ESI calculated for C10H8F2O2 [M+H]⁺, 199.05; found, 199.05. Step-2: 1:1 mixture of (S)-2-bromo-5-(difluoromethoxy)-2,3-dihydro-lH-inden-l-one and (R)-2-bromo-5-(difluoromethoxy)-2,3-dihydro- IH-inden- l-one

[0924] To a stirred solution of 5-(difluoromethoxy)-2,3-dihydroinden-l-one (52.00 g, 262.40 mmol) in EtOAc (520 mL) was added CuBr2 (117.22 g, 524.80 mmol). The resulting mixture was stirred at 80 °C for 2 h under nitrogen atmosphere. The reaction mixture was concentrated under vacuum. The resulting residue was purified by Combi Flash (Biotage Isolera Prime) which applied to 330 g silica gel column and eluted with 0 ~ 17% ethyl acetate in petroleum ether to afford a 1 : 1 mixture of (S)-2-bromo-5-(difhioromethoxy)-2,3-dihydro- lH-inden-l-one and (R)-2-bromo-5-(difluoromethoxy)-2,3-dihydro-lH-inden-l-one (62 g, 85%) as a yellow oil. MS ESI calculated for CioH/BrpaCh [M+H]⁺, 276.96, 278.96; found, 276.95, 278.95.

Step-3: 1:1 mixture of (lR,2S)-2-bromo-5-(difluoromethoxy)-2,3-dihydro-lH-inden-l-ol and ( 1 S,2R)-2-bromo-5-(difhioromethoxy)-2,3-dihydro- IH-inden- 1 -ol

[0925] To a stirred solution of a 1:1 mixture of (S)-2-bromo-5-(difluoromethoxy)-2,3- dihydro-lH-inden-l-one and (R)-2-bromo-5-(difluoromethoxy)-2,3-dihydro-lH-inden-l-one (60.00 g, 216.55 mmol) in EtOH (600 mL) was added NaBH₄ (4.10 g, 108.27 mmol) at 0 °C. The resulting mixture was stirred at room temperature for 1 h. The reaction mixture was quenched by the addition of water and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate and concentrated under vacuum to affort a 1:1 mixture of (lR,2S)-2-bromo-5-(difhioromethoxy)-2,3-dihydro-lH- inden-l-ol and (lS,2R)-2-bromo-5-(difluoromethoxy)-2,3-dihydro-lH-inden-l-ol (62.00 g, crude) as a light yellow solid. MS ESI calculated for CioH9BrF202 [M+H]⁺, 278.98, 280.98; found, 261.00, 263.00.

Step-4: 1:1 mixture of (lS,2R)-l-amino-5-(difluoromethoxy)-2,3-dihydro-lH-inden-2-ol and

(lR,2S)-l-amino-5-(difluoromethoxy)-2,3-dihydro-lH-inden-2-ol

[0926] To a stirred solution of a 1:1 mixture of (lS,2R)-2-bromo-5-(difhioromethoxy)-2,3- dihydro- lH-inden- 1 -ol and (lR,2S)-2-bromo-5-(difluoromethoxy)-2,3-dihydro- IH-inden- 1 - ol (62.00 g, 222.15 mmol) in acetonitrile (620 mL) was added H2SO4 (43.57 g, 444.31 mmol) dropwise at room temperature. The resulting mixture was stirred at 60 °C for 1 h. To the above mixture was added H2O (620 mL) at 60 °C. The resulting mixture was stirred at 80 °C for 16 h. The layers was separeated and the aqueous solution was basified with NaOH to pH ~ 8 and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under vacuum to afford a 1:1 mixture of (lS,2R)-l-amino-5-(difluoromethoxy)-2,3-dihydro-lH-inden-2-ol and (1R,2S)-1- amino-5-(difluoromethoxy)-2,3-dihydro-lH-inden-2-ol (27 g, 58% over two steps) as a light yellow solid. MS ESI calculated for C10H11F2NO2 [M+H]⁺, 216.08; found, 216.00.

Step-5: 1:1 mixture of tert-butyl N-[(lS,2R)-5-(difhioromethoxy)-2-hydroxy-2,3-dihydro-lH- inden-l-yl]carbamate and tert-butyl N-[(lR,2S)-5-(difluoromethoxy)-2-hydroxy-2,3-dihydro- lH-inden- l-yl]carbamate

[0927] To a stirred solution of a 1:1 mixture of (lS,2R)-l-amino-5-(difhioromethoxy)-2,3- dihydro-lH-inden-2-ol and (lR,2S)-l-amino-5-(difluoromethoxy)-2,3-dihydro-lH-inden-2-ol (60.00 g, 278.81 mmol) in methanol (600 mL) was added EtaN (56.43 g, 557.62 mmol) and di-tert-butyl dicarbonate (73.02 g, 334.57 mmol). The resulting mixture was stirred at room temperature for 16 h. The reaction mixture was quenched by the addition of water and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate and concentrated under vacuum to afford a 1 : 1 mixture of tertbutyl N- [( 1 S,2R)-5-(difhioromethoxy)-2-hydroxy-2,3-dihydro- IH-inden- l-yl]carbamate and tert-butyl N-[(lR,2S)-5-(difhioromethoxy)-2-hydroxy-2,3-dihydro-lH-inden-l-yl]carbamate (88.00 g, crude) as brown solid. MS ESI calculated for C15H19F2NO4 [M+H]⁺, 316.13; found, 316.20.

Step-6: 1:1 mixture of tert-butyl N-[(1S, 2R)-5-(difhioromethoxy )-2-[(2S)-2- hydroxypropoxy]-2,3-dihydro-lH-inden-l-yl]carbamate and tert-butyl N-[(lR,2S)-5- (difluoromethoxy)-2- [(2S)-2-hydroxypropoxy] -2,3-dihydro- IH-inden- 1 -yl]carbamate

[0928] To a stirred solution of a 1:1 mixture of tert-butyl N-[(lS,2R)-5-(difluoromethoxy)- 2-hydroxy-2,3-dihydro-lH-inden-l-yl]carbamate and tert-butyl N-[(lR,2S)-5-

(difluoromethoxy)-2-hydroxy-2,3-dihydro-lH-inden-l-yl]carbamate (40.00 g, 126.85 mmol) and NaOH (35.52 g, 887.99 mmol) in DCM (100 mL) was added (4S)-4-methyl-l,3,2-X-6- dioxathiolane-2, 2-dione (supplier: Suzhou spark Biotechnology Co., Ltd. CAS# 174953-30- 1) (22.78 g, 164.91 mmol) dropwise at room temperature under nitrogen atmosphere. The resulting mixture was stirred at room temperature for 2 h under nitrogen atmosphere. The resulting mixture was concentrated under vacuum. The residue was dissolved in H2O. The aqueous solution was neutralized with aq. HC1 to pH 7-8. The resulting mixture was extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SC>4. After filtration, the filtrate was concentrated under reduced pressure. The residue was dissolved in 2-methoxy-2-methylpropane (1914 mL)/H2O (66 mL). To the above solution was added a solution of TsOH (14.11 g, 81.94 mmol) in dioxane (540 mL) at room temperature. The resulting mixture was stirred at 40 °C overnight. The reaction was quenched with aq. NaHCCh at room temperature. The resulting mixture was extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SO4. After filtration, the filtrate was concentrated under reduced pressure. The resulting residue was purified by normal phase flash chromatography which applied to 330 g silica gel column and eluted with 0-40% ethyl acetate in petroleum ether to afford a 1:1 mixture of tert-butyl N- [(lS,2R)-5-(difluoromethoxy)-2-[(2S)-2-hydroxypropoxy]-2,3-dihydro-lH-inden-l- yl]carbamate and tert-butyl N-[(lR,2S)-5-(difluoromethoxy)-2-[(2S)-2-hydroxypropoxy]-2,3- dihydro-lH-inden-l-yl]carbamate (36 g, 70% over two steps) as a brown oil. MS ESI calculated for C18H25F2NO5 [M+H]⁺, 316.13; found, 316.20.

Step-7: 1:1 mixture of tert-butyl (3R,4aS,9aR)-7-(difluoromethoxy)-3-methyl-2,3,9,9a- tetrahydroindeno[2,l-b][l,4]oxazine-4(4aH)-carboxylate and tert-butyl (3R,4aR,9aS)-7- (difluoromethoxy)-3-methyl-2,3,9,9a-tetrahydroindeno[2,l-b][l,4]oxazine-4(4aH)- carboxylate

[0929] To a stirred solution of a 1:1 mixture of tert-butyl N-[(lS,2R)-5-(difluoromethoxy)- 2-[(2S)-2-hydroxypropoxy]-2,3-dihydro-lH-inden-l-yl]carbamate and tert-butyl N-[(1R,2S)- 5-(difluoromethoxy)-2-[(2S)-2-hydroxypropoxy]-2,3-dihydro-lH-inden-l-yl]carbamate (36 g, 96.41 mmol) in toluene (360 mL) was added 2-(tributyl-V-phosphaneylidene)acetonitrile (46.54 g, 192.82 mmol) (CAS No. 157141-27-0) dropwise at room temperature under nitrogen atmosphere. The resulting mixture was stirred at 110 °C overnight under nitrogen atmosphere. The resulting mixture was concentrated under vacuum. The resulting residue was purified by normal phase flash chromatography which applied to 330 g silica gel column and eluted with 0-15% ethyl acetate in petroleum ether to afford a 1:1 mixture of tert-butyl (3R,4aS,9aR)-7-(difluoromethoxy)-3-methyl-2,3,9,9a-tetrahydroindeno[2,l-b][l,4]oxazine- 4(4aH)-carboxylate and tert-butyl (3R,4aR,9aS)-7-(difluoromethoxy)-3-methyl-2,3,9,9a- tetrahydroindeno[2,l-b][l,4]oxazine-4(4aH)-carboxylate (27.00 g, 78%) as a yellow oil. MS ESI calculated for C18H23F2NO4 [M+H]⁺, 356.16; found, 356.00.

Step-8: (3R,4aR,9aS)-7-(difluoromethoxy)-3-methyl-2,3,4,4a,9,9a-hexahydroindeno[2,l- b][ 1,4] oxazine hydrochloride (A15, isomer 1):

A15, isomer 1 . _an(j

(3R,4aS ,9aR)-7-(difluoromethoxy)-3-methyl-2,3 ,4,4a,9,9a-hexahydroindeno [2,1- b][ 1,4] oxazine hydrochloride (A15, isomer 2):

A15, isomer 2

[0930] To a solution of a 1:1 mixture of tert-butyl (3R,4aS,9aR)-7-(difhioromethoxy)-3- methyl-2,3,9,9a-tetrahydroindeno[2,l-b] [l,4]oxazine-4(4aH)-carboxylate and tert-butyl (3R,4aR,9aS)-7-(difluoromethoxy)-3-methyl-2,3,9,9a-tetrahydroindeno[2,l-b][l,4]oxazine- 4(4aH)-carboxylate (37.00 g, 104.11 mmol) in EtOAc (400 mL) was added hydrogen chloride (4.0 M in ethyl acetate) (370 mL) at 0 °C. The mixture was stirred at room temperature for 1 h. The resulting mixture was concentrated under vacuum. The residue was purified by trituration with EtOAc to afford (3R,4aS,9aR)-7-(difluoromethoxy)-3-methyl- 2,3,4,4a,9,9a-hexahydroindeno[2,l-b][l,4]oxazine hydrochloride (A15, isomer 2) (10.8 g, 35%) as a white solid. The stereochemistry was confirmed by NOE. MS ESI calculated for (C13H16F2NO2CI) [M+H]⁺, 256.11; found, 256.20. 'H NMR (400 MHz, DMSO-J₆) 8 10.91 (br, 1H), 8.86 (br, 1H), 7.68 (d, J = 8.4 Hz, 1H), 7.46 - 7.09 (m, 3H), 4.65 - 4.58 (m, 2H), 3.86 - 3.82 (m, 1H), 3.59 - 3.54 (m, 1H), 3.37 - 3.35 (m, 1H), 3.29 - 3.23 (m, 1H), 3.09 - 3.04 (m, 1H), 1.20 (d, J = 6.4 Hz, 3H).

[0931] The ethyl acetate filtrate from above was concentrated under vacuum. The residue was triturated with MTBE to afford (3R,4aR,9aS)-7-(difhioromethoxy)-3-methyl- 2,3,4,4a,9,9a-hexahydroindeno[2,l-b][l,4]oxazine hydrochloride (A15, isomer 1) (14.8 g, 48%) as a white solid. The stereochemistry was confirmed by NOE. MS ESI calculated for (C13H16F2NO2CI) [M+H]⁺, 256.11; found, 256.20. 'H NMR (300 MHz, DMSO- fe) 6 10.56 (br, 2H), 8.02 (d, J = 8.4 Hz, 1H), 7.51 - 6.98 (m, 3H), 4.85 - 4.84 (m, 1H), 4.54 - 4.52 (m, 1H), 3.73 - 3.68 (m, 1H), 3.54 - 3.50 (m, 1H), 3.15 - 3.08 (m, 2H), 2.88 - 2.82 (m, 1H), 1.25 (d, J = 6.3 Hz, 3H).

Intermediate A16: (3R,4aS,9aR)-7-chloro-3-methyl-2,3,4,4a,9,9a-hexahydroindeno[2,l- b][ 1,4] oxazine (A16)

A16

Step-1: 1:1 mixture of (S)-2-bromo-5-chloro-2,3-dihydroinden-l-one and (R)-2-bromo-5- chloro-2,3-dihydroinden- 1 -one

[0932] To a stirred mixture of 5-chloro-2,3-dihydroinden-l-one (50.00 g, 300.12 mmol) in Et2O (500 mL) was added Br2 (47.90 g, 300.120 mmol) dropwise at 0 °C under nitrogen atmosphere. The resulting mixture was stirred at 25 °C for 3 h. The reaction mixture was quenched by water and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under vacuum. The resulting residue was purified by normal phase flash column chromatography with 0-30% ethyl acetate in petroleum ether to afford a 1 : 1 mixture of (S)-2-bromo-5-chloro- 2,3-dihydroinden-l-one and (R)-2-bromo-5-chloro-2,3-dihydroinden-l-one (68.00 g, 90%) as a yellow solid. MS (ESI) calculated for (C₉H₆BrClO) [M+H]⁺, 244.93, 246.93; found, 244.95, 246.95.

Step-2: 1:1 mixture of (lR,2S)-2-bromo-5-chloro-2,3-dihydro-lH-inden-l-ol and (lS,2R)-2- bromo-5-chloro-2,3-dihydro- 1 H-inden- l-ol

[0933] To a stirred solution of a 1:1 mixture of (S)-2-bromo-5-chloro-2,3-dihydroinden-l- one and (R)-2-bromo-5-chloro-2,3-dihydroinden-l-one (68.00 g, 276.98 mmol) in methanol (600 mL) was added NaBtU (20.90 g, 553.972 mmol) in portions at 0 °C. The resulting mixture was stirred at room temperature for additional 3 h. The reaction was quenched with water/ice at 0 °C. The resulting mixture was extracted with DCM three times. The combined organic layers were washed with water, dried over anhydrous Na₂SC>4. After filtration, the filtrate was concentrated under reduced pressure to afford a 1:1 mixture of (lR,2S)-2-bromo- 5-chloro-2,3-dihydro- 1 H-inden- 1 -ol and ( 1 S,2R)-2-bromo-5-chloro-2,3-dihydro- 1 H-inden- 1 - ol (65.00 g, 99%) as an off-white solid. MS (ESI) calculated for (C₉H₈BrClO) [M+H]⁺, 246.94, 248.94; found, 244.90, 246.90. ’H NMR (400 MHz, DMSO-d₆) 8 7.38 - 7.26 (m, 3H), 5.93 (d, J = 6.0 Hz, 1H), 4.99 - 4.84 (m, 2H), 3.45 (dd, J= 17.2, 5.2 Hz, 1H), 3.19 (dd, J = 17.2, 2.6 Hz, 1H).

Step-3: 1:1 mixture of (lS,2R)-l-amino-5-chloro-2,3-dihydro-lH-inden-2-ol and (1R,2S)-1- amino-5-chloro-2,3-dihydro-lH-inden-2-ol

[0934] To a stirred solution of a 1:1 mixture of (lR,2S)-2-bromo-5-chloro-2,3-dihydro-lH- inden-l-ol and (lS,2R)-2-bromo-5-chloro-2,3-dihydro-lH-inden-l-ol (96.40 g, 389.46 mmol) and MeCN (31.90 g, 778.92 mmol) in DCE (900 mL) was added H₂SO₄ (cone.) (57.29 g, 584.195 mmol) in portions at room temperature. The resulting mixture was stirred at room temperature for 3 h. Then H₂O (600 mL) was added to the above mixture at room temperature. The resulting mixture was stirred at 60 °C overnight. The resulting mixture was diluted by water (-600 mL) and extracted with DCM. Then the aqueous layer was collected and basified with NaOH (25% aqueous solution) to pH 12. The precipitated solids were collected by filtration and dried over vacuum to afford a 1:1 mixture of (lS,2R)-l-amino-5- chloro-2,3-dihydro- 1 H-inden-2-ol and ( 1 R,2S)- 1 -amino-5-chloro-2,3-dihydro- 1 H-inden-2-ol (50.40 g, 90%) as an off-white solid. MS ESI calculated for C14H10F3N [M+H]⁺, 183.05; found, 184.00.

Step-4: 1:1 mixture of tert-butyl ((lS,2R)-5-chloro-2-hydroxy-2,3-dihydro-lH-inden-l- yl)carbamate and tert-butyl ((lR,2S)-5-chloro-2-hydroxy-2,3-dihydro-lH-inden-l- yl)carbamate

[0935] To a stirred solution of a 1:1 mixture of (lS,2R)-l-amino-5-chloro-2,3-dihydro-lH- inden-2-ol and (lR,2S)-l-amino-5-chloro-2,3-dihydro-lH-inden-2-ol (34.00 g, 185.14 mmol) in methanol (340 mL) was added di-tert-butyl dicarbonate (32.30 g, 148.11 mmol) at room temperature. The resulting mixture was stirred at room temperature overnight. The mixture was concentrated under vacuum. The residue was purified by silica gel column chromatography, eluted with 0-50% ethyl acetate in petroleum ether to afford a 1:1 mixture of tert-butyl ((lS,2R)-5-chloro-2-hydroxy-2,3-dihydro-lH-inden-l-yl)carbamate and tertbutyl ((lR,2S)-5-chloro-2-hydroxy-2,3-dihydro-lH-inden-l-yl)carbamate (36.00 g, 68%) as an off-white solid. MS (ESI) calculated for (C14H18CINO3) [M+H]⁺, 284.10; found, 284.25.

Step-5: 1:1 mixture of (S)-l-(((lS,2R)-l-amino-5-chloro-2,3-dihydro-lH-inden-2- yl)oxy)propan-2-ol and (S)- 1 -(((1R,2S)- 1 -amino-5-chloro-2,3-dihydro- lH-inden-2- yl)oxy)propan-2-ol

[0936] To a stirred mixture of a 1:1 mixture of tert-butyl ((lS,2R)-5-chloro-2-hydroxy-2,3- dihydro-lH-inden-l-yl)carbamate and tert-butyl ((lR,2S)-5-chloro-2-hydroxy-2,3-dihydro- lH-inden-l-yl)carbamate (44.80 g, 157.88 mmol) in DCM (450 mL) were added tetrabutylazanium hydrogen sulfate (10.72 g, 31.57 mmol) and NaOH (44.20 g, 1105.19 mmol) at room temperature. This was followed by the addition of (4S)-4-methyl-l,3,2-6- dioxathiolane-2, 2-dione (supplier: Suzhou spark Biotechnology Co., Ltd. CAS# 174953-30- 1) (28.35 g, 205.25 mmol) in dropwise at room temperature. The resulting mixture was warmed at room temperature for 1 h with stirring. The resulting mixture was concentrated under reduced pressure. The residue was dissolved in water (450 mL), and then H2SO4 (cone.) (309.68 g, 3157.70 mmol) was added slowly at 0 °C. The resulting mixture was stirred at 70 °C overnight. The mixture was basified with NaOH (aq.) to pH 8. The resulting mixture was extracted with DCM. The combined organic layers were washed with water, dried over anhydrous Na2SC>4. After filtration, the filtrate was concentrated under reduced pressure to afford a 1:1 mixture of (S)-l-(((lS,2R)-l-amino-5-chloro-2,3-dihydro-lH-inden- 2-yl)oxy)propan-2-ol and (S)-l-(((lR,2S)-l-amino-5-chloro-2,3-dihydro-lH-inden-2- yl)oxy)propan-2-ol (35.40 g, 93%) as a brown oil. MS (ESI) calculated for (C12H16CINO2) [M+H]⁺, 242.09; found, 242.25.

Step-6: 1:1 mixture of tert-butyl ((lS,2R)-5-chloro-2-((S)-2-hydroxypropoxy)-2,3-dihydro- lH-inden-l-yl)carbamate and tert-butyl ((lR,2S)-5-chloro-2-((S)-2-hydroxypropoxy)-2,3- dihydro- lH-inden- 1 -yl)carbamate

[0937] To a stirred solution of a 1:1 mixture of (S)-l-(((lS,2R)-l-amino-5-chloro-2,3- dihydro-lH-inden-2-yl)oxy)propan-2-ol and (S)-l-(((lR,2S)-l-amino-5-chloro-2,3-dihydro- lH-inden-2-yl)oxy)propan-2-ol (60.00 g, 248.22 mmol) and di-tert-butyl dicarbonate (65.00 g, 297.86 mmol) in methanol (600 mL) was added EtsN (75.30 g, 744.66 mmol) at room temperature. The resulting mixture was stirred at room temperature overnight. The mixture was concentrated under vacuum. The residue was purified by silica gel column chromatography, eluted with 0-20% ethyl acetate in petroleum ether to afford a 1:1 mixture of tert-butyl ((lS,2R)-5-chloro-2-((S)-2-hydroxypropoxy)-2,3-dihydro-lH-inden-l- yl)carbamate and tert-butyl ((lR,2S)-5-chloro-2-((S)-2-hydroxypropoxy)-2,3-dihydro-lH- inden-l-yl)carbamate (67.50 g, 79%) as a yellow solid. MS (ESI) calculated for (C17H24CINO4) [M+H]⁺, 342.14, 344.14; found, 342.25, 344.25. ¹H NMR (400 MHz, DMSO-de) 8 7.38 - 7.11 (m, 3H), 6.88 - 6.97 (m, 1H), 4.95 - 4.99 (m, 1H), 4.66 and 4.56 (d, J = 4.2 Hz, 1H), 4.26 - 4.10 (m, 1H), 3.62 - 3.73 (m, 1H), 3.40 - 3.11 (m, 2H), 2.96 - 2.98 (m, 2H), 1.45 (s, 9H), 1.00 (d, J= 6.3, Hz, 3H).

Step-7: tert-butyl (3R,4aS,9aR)-7-chloro-3-methyl-2,3,9,9a-tetrahydroindeno[2,l- b] [ 1 ,4] oxazine-4(4aH)-carboxylate tert-butyl (3R,4aR,9aS)-7-chloro-3-methyl-2,3,9,9a-tetrahydroindeno[2,l-b][l,4]oxazine-

4(4aH)-carboxylate

[0938] To a stirred solution of a 1:1 mixture of tert-butyl ((lS,2R)-5-chloro-2-((S)-2- hydroxypropoxy)-2,3-dihydro-lH-inden-l-yl)carbamate and tert-butyl ((lR,2S)-5-chloro-2- ((S)-2-hydroxypropoxy)-2,3-dihydro-lH-inden-l-yl)carbamate (47.40 g, 138.66 mmol) in anhydrous toluene (500 mL) was added 2-(tributyl-X⁵-phosphaneylidene)acetonitrile (66.94 g, 277.33 mmol) (CAS No. 157141-27-0) at room temperature under nitrogen atmosphere. The resulting mixture was stirred at 110 °C overnight under nitrogen atmosphere. The resulting mixture was concentrated under vacuum. The residue was purified by silica gel column chromatography, eluted with 0-10% ethyl acetate in petroleum ether to afford a mixture of tert-butyl (3R,4aS,9aR)-7-chloro-3-methyl-2,3,9,9a-tetrahydroindeno[2,l-b][l,4]oxazine- 4(4aH)-carboxylate and tert-butyl (3R,4aR,9aS)-7-chloro-3-methyl-2,3,9,9a- tetrahydroindeno[2,l-b][l,4]oxazine-4(4aH)-carboxylate (40.20 g) as a yellow oil.

[0939] About 60 g of the mixture was separated by Prep-Chiral SFC with following condition [Column: CHIRALPAK IG, 7*25cm, 10 pm; Mobile Phase A: CO2, Mobile Phase B: IPA (0.1% 7M NHs-MeOH); Flow rate: 200 mL/min; Gradient: isocratic 20% B; Wave Length: 220 nm; RTl(min): 7.97; RT2(min): 10.25; Injection Volume: 2 mL; Number Of Runs: 165] to afford tert-butyl (3R,4aS,9aR)-7-chloro-3-methyl-2,3,9,9a- tetrahydroindeno[2,l-b][l,4]oxazine-4(4aH)-carboxylate (20.60 g) as yellow oil with the first peak on chiral SFC. The stereochemistry was confirmed by NOE. MS (ESI) calculated for (C17H22CINO3) [M+H]⁺, 324.13; found, 324.05. 'H NMR (400 MHz, DMSO-d₆) 6 7.30 (s, 1H), 7.30 - 7.23 (m, 1H), 7.18 - 6.96 (m, 1H), 5.08 - 5.04 (m, 1H), 4.24 (t, 7 = 4.4 Hz, 1H), 3.94 - 3.90 (m, 1H), 3.59 - 3.52 (m, 2H), 3.13 (dd, J= 16.8, 4.6 Hz, 1H), 2.85 (d, J= 16.8 Hz, 1H), 1.64 - 1.36 (m, 9H), 0.0.81 - 0.76 (m, 3H).

[0940] The chiral resolution also afford tert-butyl (3R,4aR,9aS)-7-chloro-3-methyl- 2,3,9,9a-tetrahydroindeno[2,l-b][l,4]oxazine-4(4aH)-carboxylate (21.60 g) as yellow oil with the second peak on chiral SFC. The stereochemistry was confirmed by NOE. MS (ESI) calculated for (C17H22CINO3) [M+H]⁺, 324.13; found, 324.05. 'H NMR (400 MHz, DMSO- d₆) 5 7.36 (d, J = 2.0 Hz, 1H), 7.29 (dd, 7 = 8.0, 2.0 Hz, 1H), 7.06 (dd, 7 = 8.0, 1.2 Hz, 1H), 5.18 (d, 7 = 4.6 Hz, 1H), 4.62 (t, 7 = 4.4 Hz, 1H), 3.58 - 3.44 (m, 1H), 3.39 (dd, 7 = 11.8, 3.0 Hz, 1H), 3.29 (dd, 7 = 11.8, 5.0 Hz, 1H), 3.09 (dd, 7 = 16.6, 4.2 Hz, 1H), 2.84 (d, 7= 16.6 Hz, 1H), 1.49 (s, 9H), 1.28 (d, 7 = 6.4 Hz, 3H).

Step-8 : (3R,4aS ,9aR)-7 -chloro-3-methyl-2,3 ,4,4a,9,9a-hexahydroindeno[2, 1 -b] [ 1 ,4] oxazine (A16)

A16

[0941] To a stirred solution of tert-butyl (3R,4aS,9aR)-7-chloro-3-methyl- 2H,3H,4aH,9H,9aH-indeno[2,l-b][l,4]oxazine-4-carboxylate (10.00 g, 30.88 mmol) in DCM (100 mL) was added Zinc bromide (13.91 g, 61.76 mmol) at room temperature. The resulting mixture was stirred at room temperature overnight. The reaction mixture was filtered, the filter cake was washed with DCM. The organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered and concentrated under vacuum to afford (3R,4aS,9aR)-7- chloro-3-methyl-2,3,4,4a,9,9a-hexahydroindeno[2,l-b][l,4]oxazine (A16) (5.00 g, 72%) as a yellow solid. MS (ESI) calculated for (C12H14CINO) [M+H]⁺, 224.08; found, 224.10. 'H NMR (300 MHz, DMSO-7₆) 6 7.43 - 7.33 (m, 2H), 7.27 (dd, 7= 8.0, 2.0 Hz, 1H), 4.33 - 4.26 (m, 1H), 4.13 (d, 7= 5.2 Hz, 1H), 3.60 (dd, 7= 11.2, 3.2 Hz, 1H), 3.33 (dd, 7= 11.2, 8.0 Hz, 1H), 3.20 (dd, 7 = 15.8, 7.0 Hz, 1H), 3.01 - 2.78 (m, 2H), 0.91 (d, 7 = 6.4 Hz, 3H). Intermediate A17, isomer 1: (2R,4aS,10bR)-8-chloro-2-methyl- lH,2H,3H,4aH,5H,6H,10bH-[l,4]oxazino[3,2-f]quinoline, isomer 1:

A17, isomer 1 _{; and}

Intermediate A17, isomer 2: (2R,4aR,10bS)-8-chloro-2-methyl- lH,2H,3H,4aH,5H,6H,10bH-[l,4]oxazino[3,2-f]quinoline, isomer 2:

A17, isomer 2

Step 1: 1:1 mixture of (S)-2-chloro-5,6,7,8-tetrahydroquinolin-5-ol and (R)-2-chloro-5, 6,7,8- tetrahydroquinolin-5-ol

[0942] To a stirred solution of 2-chloro-7,8-dihydro-6H-quinolin-5-one (12.00 g, 66.07 mmol) in MeOH (120 mL) was added NaBH4 (5.00 g, 132.14 mmol) in portions at 0 °C. The resulting mixture was stirred at room temperature for 2 h. The resulting mixture was extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SO4. After filtration, the filtrate was concentrated under reduced pressure to afford a 1:1 mixture of (S)-2-chloro-5,6,7,8-tetrahydroquinolin-5-ol and (R)-2-chloro-5, 6,7,8- tetrahydroquinolin-5-ol (12.00 g, 89%) as a yellow oil. MS ESI calculated for C9H10CINO EM+H]⁺, 184.05; found, 184.00.

Step 2: 2-chloro-7,8-dihydroquinoline

[0943] A solution of 2-chloro-5,6,7,8-tetrahydroquinolin-5-ol (11.00 g, 59.90 mmol) and PPA (50 mL) was stirred at 120 °C for 2 h. The reaction mixture was cooled at room temperature and quenched by water. The mixture was basified to pH 8 with NaOH. The resulting mixture was extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous NaiSt After filtration, the filtrate was concentrated under reduced pressure to afford 2-chloro-7,8-dihydroquinoline (8.6 g, 86%) as a yellow oil. MS ESI calculated for C₉H₈C1N [M+H]⁺, 166.03; found, 166.05.

Step 3: 1:1 mixture of (5S,6S)-5-amino-2-chloro-5,6,7,8-tetrahydroquinolin-6-ol and (5R,6R)-5-amino-2-chloro-5,6,7,8-tetrahydroquinolin-6-ol

[0944] To a stirred solution of 2-chloro-7,8-dihydroquinoline (8.60 g, 51.92 mmol) in THF (10 mL) was added NBS (9.24 g, 51.92 mmol) at room temperature. The resulting mixture was stirred at room temperature for 16 h. The residue was dissolved in water. The resulting mixture was extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SO4. After filtration, the filtrate was concentrated under reduced pressure. The residue was dissolved in a mixture of MeOH (14 mL) and ammonium hydroxide (28% in water) (140 mL), the mixture was stirred at room temperature for 16 h. The resulting mixture was concentrated under vacuum to afford a 1:1 mixture of (5S,6S)-5- amino-2-chloro-5,6,7,8-tetrahydroquinolin-6-ol and (5R,6R)-5-amino-2-chloro-5, 6,7,8- tetrahydroquinolin-6-ol (8.1 g, crude) as a yellow solid. MS ESI calculated for C9H11CIN2O [M+H]⁺, 199.06; found, 199.05.

Step 4: 1:1 mixture of N-[(5S,6S)-2-chloro-6-hydroxy-5,6,7,8-tetrahydroquinolin-5- yl]benzamide and N- [(5R,6R)-2-chloro-6-hydroxy-5,6,7,8-tetrahydroquinolin-5- yl]benzamide

[0945] To a stirred solution of a 1:1 mixture of (5S,6S)-5-amino-2-chloro-5, 6,7,8- tetrahydroquinolin-6-ol and (5R,6R)-5-amino-2-chloro-5,6,7,8-tetrahydroquinolin-6-ol (14.10 g, 70.47 mmol) and EtsN (21.39 g, 211.42 mmol) in DCM (140 mL) was added benzoyl chloride (6.93 g, 49.33 mmol) at 0°C. The reaction was poured into water/ice. The resulting mixture was extracted with DCM. The combined organic layers were washed with brine, dried over anhydrous Na2SC>4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-10% ethyl acetate in petroleum ether to afford a 1:1 mixture of N-[(5S,6S)-2-chloro-6-hydroxy- 5,6,7,8-tetrahydroquinolin-5-yl]benzamide and N-[(5R,6R)-2-chloro-6-hydroxy-5, 6,7,8- tetrahydroquinolin-5-yl]benzamide (8.90 g, 41%) as a brown solid. MS ESI calculated for C16H15CIN2O2 [M+H]⁺, 303.08; found, 303.05.

Step 5: 1:1 mixture of (3aR,9bS)-7-chloro-2-phenyl-3a,4,5,9b-tetrahydrooxazolo[4,5- f]quinoline and (3aS,9bR)-7-chloro-2-phenyl-3a,4,5,9b-tetrahydrooxazolo[4,5-f]quinoline

[0946] To a stirred solution of a 1 : 1 mixture of N-[(5S,6S)-2-chloro-6-hydroxy-5, 6,7,8- tetrahydroquinolin-5-yl]benzamide and N-[(5R,6R)-2-chloro-6-hydroxy-5, 6,7,8- tetrahydroquinolin-5-yl]benzamide (8.90 g, 29.39 mmol) in DCM (180 mL) was added Thionyl chloride (8.74 g, 73.47 mmol) dropwise at room temperature. The reaction was poured into water/ice at room temperature. The mixture was basified to pH 7 with NaHCCh (sat.). The resulting mixture was extracted with DCM. The combined organic layers were washed with brine, dried over anhydrous NajSC . After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-30% ethyl acetate in petroleum ether to afford a 1:1 mixture of (3aR,9bS)-7-chloro-2-phenyl-3a,4,5,9b-tetrahydrooxazolo[4,5-f|quinoline and (3aS,9bR)- 7-chloro-2-phenyl-3a,4,5,9b-tetrahydrooxazolo[4,5-f]quinoline (4.90 g, 58%) as a white solid. MS ESI calculated for C16H13CIN2O [M+H]⁺, 285.07; found, 285.05.

Step 6: 1:1 mixture of (5S,6R)-5-amino-2-chloro-5,6,7,8-tetrahydroquinolin-6-ol and (5R,6S)-5-amino-2-chloro-5,6,7,8-tetrahydroquinolin-6-ol

[0947] A solution of a 1:1 mixture of (3aR,9bS)-7-chloro-2-phenyl-3a,4,5,9b- tetrahydrooxazolo[4,5-f]quinoline and (3aS,9bR)-7-chloro-2-phenyl-3a,4,5,9b- tetrahydrooxazolo[4,5-f]quinoline (4.80 g, 16.85 mmol) and HC1 (cone., 10 mL) in 1,4- dioxane (40 mL) was stirred at 100 °C for 16 h. The resulting mixture was concentrated under vacuum to afford a 1:1 mixture of (5S,6R)-5-amino-2-chloro-5, 6,7,8- tetrahydroquinolin-6-ol and (5R,6S)-5-amino-2-chloro-5,6,7,8-tetrahydroquinolin-6-ol (5.8 g, crude) as a yellow oil. MS ESI calculated for C9H11CIN2O [M+H]⁺, 199.06; found, 199.10.

Step 7: 1:1 mixture of tert-butyl ((5S,6R)-2-chloro-6-hydroxy-5,6,7,8-tetrahydroquinolin-5- yl)carbamate and tert-butyl ((5R,6S)-2-chloro-6-hydroxy-5,6,7,8-tetrahydroquinolin-5- yl)carbamate

[0948] To a stirred solution of a 1:1 mixture of (5S,6R)-5-amino-2-chloro-5, 6,7,8- tetrahydroquinolin-6-ol and (5R,6S)-5-amino-2-chloro-5,6,7,8-tetrahydroquinolin-6-ol (5.80 g, 29.19 mmol) and EtsN (8.86 g, 87.59 mmol) in MeOH (60 mL) was added di-tert-butyl dicarbonate (12.74 g, 58.39 mmol) at room temperature. The mixture was stirred at room temperature for 16 h. The resulting mixture was concentrated under vacuum. The residue was purified by silica gel column chromatography, eluted with 0-50% ethyl acetate in petroleum ether to afford a 1:1 mixture of tert-butyl ((5S,6R)-2-chloro-6-hydroxy-5, 6,7,8- tetrahydroquinolin-5-yl)carbamate and tert-butyl ((5R,6S)-2-chloro-6-hydroxy-5, 6,7,8- tetrahydroquinolin-5-yl)carbamate (3.03 g, 34%) as a colorless oil. MS ESI calculated for C14H19CIN2O3 [M+H]⁺, 299.11; found, 299.11.

Step 8: 1:1 mixture of tert-butyl ((5S,6R)-2-chloro-6-((S)-2-hydroxypropoxy)-5, 6,7,8- tetrahydroquinolin-5-yl)carbamate and tert-butyl ((5R,6S)-2-chloro-6-((S)-2- hydroxypropoxy)-5,6,7,8-tetrahydroquinolin-5-yl)carbamate

[0949] To a stirred solution of a 1:1 mixture of tert-butyl ((5S,6R)-2-chloro-6-hydroxy- 5,6,7,8-tetrahydroquinolin-5-yl)carbamate and tert-butyl ((5R,6S)-2-chloro-6-hydroxy- 5,6,7,8-tetrahydroquinolin-5-yl)carbamate (2.00 g, 6.69 mmol) in DCM (40 mL) were added tetrabutylazanium hydrogen sulfate (0.45 g, 1.33 mmol) and NaOH (1.87 g, 46.75 mmol), this was followed by the addition of (4S)-4-methyl-l, 3, 2-X-6-dioxathiolane-2, 2-dione (supplier: Suzhou spark Biotechnology Co., Ltd. CAS# 174953-30-1) (1.20 g, 8.70 mmol) at room temperature under nitrogen atmosphere. The resulting mixture was stirred at room temperature for 4 h under nitrogen atmosphere. The resulting mixture was concentrated under reduced pressure. The resulting mixture was diluted with water. The mixture was neutralized to pH 7 with HC1 (cone.). The resulting mixture was extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous NaiSCM. After filtration, the filtrate was concentrated under reduced pressure. The residue was dissolved in 2-methoxy-2- methylpropane (90 mL), then H2O (3 mL, 166.52 mmol), TsOH (0.70 g, 4.08 mmol) and dioxane (25 mL, 295.09 mmol) were added at room temperature under nitrogen atmosphere. The resulting mixture was stirred at 40 °C for 2 h. The reaction was quenched with water/ice. The mixture was neutralized to pH 7 with NaHCCh (sat.). The resulting mixture was extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SO4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-50% ethyl acetate in petroleum ether to afford a 1:1 mixture of tert-butyl ((5S,6R)-2-chloro-6-((S)-2- hydroxypropoxy)-5,6,7,8-tetrahydroquinolin-5-yl)carbamate and tert-butyl ((5R,6S)-2- chloro-6-((S)-2-hydroxypropoxy)-5,6,7,8-tetrahydroquinolin-5-yl)carbamate (1.20 g, 47%) as a white solid. MS ESI calculated for C17H25CIN2O4 [M+H]⁺, 357.15; found, 357.10.

Step 9: (2R,4aS,10bR)-8-chloro-2-methyl-2,3,4a,5,6,10b-hexahydro-lH-[l,4]oxazino[3,2- f]quinoline, isomer 1 (A17, isomer 1):

A17, isomer 1 _{; and}

(2R,4aR,10bS)-8-chloro-2-methyl-2,3,4a,5,6,10b-hexahydro-lH-[l,4]oxazino[3,2- f]quinoline, isomer 2 (A17, isomer 2)

A17, isomer 2

[0950] To a stirred solution of a 1:1 mixture of tert-butyl ((5S,6R)-2-chloro-6-((S)-2- hydroxypropoxy)-5,6,7,8-tetrahydroquinolin-5-yl)carbamate and tert-butyl ((5R,6S)-2- chloro-6-((S)-2-hydroxypropoxy)-5,6,7,8-tetrahydroquinolin-5-yl)carbamate (2.00 g, 5.60 mmol) and TEA (1.70 g, 16.81 mmol) in DCM (24 mL) was added MS2O (1.46 g, 8.40 mmol) at 0 °C. The resulting mixture was stirred at room temperature for 2 h. The reaction was quenched by water. The resulting mixture was extracted with CH2CI2. The combined organic layers were washed with brine, dried over anhydrous Na2SC>4. After filtration, the filtrate was concentrated under reduced pressure. The residue was dissolved in DCM (24 mL), then TFA (8 mL) was added to the mixture at room temperature. The resulting mixture was stirred at room temperature for 1 h. The resulting mixture was concentrated under vacuum. The residue was dissolved in MeCN (20 mL), this was followed by the addition of 1,2,2,6,6-pentamethylpiperidine (8.70 g, 56.05 mmol) at room temperature. The resulting mixture was stirred at 60 °C for additional 16 h. The resulting mixture was concentrated under vacuum. The residue was purified by silica gel column chromatography, eluted with 0- 50% ethyl acetate in petroleum ether to afford a mixture isomers, which was further purified by Prep- Achiral SFC with the following conditions (Column: DAICEL DCpak P4VP 3*25 cm, 5 pm; Mobile Phase A: CO2, Mobile Phase B: IPA (20 mM NH3); Flow rate: 60 mL/min; Gradient: isocratic 32% B; Column Temperature (°C): 35; Back Pressure (bar): 100; Wave Length: 220 nm; RT1 (min): 3.90; RT2 (min): 6.50; Sample Solvent: MeOH; Injection Volume: 1.5 mL; Number Of Runs: 10.0) to afford (2R,4aS,10bR)-8-chloro-2-methyl- 2,3,4a,5,6,10b-hexahydro-lH-[l,4]oxazino[3,2-f]quinoline (A17, isomerl) (460 mg, 34%) as a white solid. The stereochemistry was confirmed by NOE. MS ESI calculated for C12H15CIN2O [M+H]⁺, 239.09; found, 239.15. 'H NMR (400 MHz, DMSO-de) 5 8.13 (d, J = 8.4 Hz, 1H), 7.39 (d, J= 8.4 Hz, 1H), 4.17 - 4.16 (m, 1H), 3.94 - 3.93 (m, 1H), 3.69 - 3.67 (m, 1H), 3.29 - 3.12 (m, 1H), 2.97 - 2.80 (m, 1H), 2.74 - 2.53 (m, 2H), 2.08 - 2.07 (m, 1H), 1.99 - 1.83 (m, 1H), 0.93 (d, J = 6.4 Hz, 3H).

[0951] The Achiral SFC purification also afford (2R,4aR,10bS)-8-chloro-2-methyl- 2,3,4a,5,6,10b-hexahydro-lH-[l,4]oxazino[3,2-f]quinoline (A17, isomerl) (500 mg, 37%) as a yellow oil. The stereochemistry was confirmed by NOE. MS ESI calculated for C12H15CIN2O [M+H]⁺, 239.09; found, 239.15. 'H NMR (400 MHz, DMSO-tfc) 5 7.90 (d, J = 8.2 Hz, 1H), 7.50 (d, J= 8.2 Hz, 1H), 4.63 - 4.62 (m, 1H), 4.33 - 4.32 (m, 1H), 3.86 - 3.62 (m, 1H), 3.48 - 3.47 (m, 2H), 2.99 - 2.97 (m, 2H), 2.76 - 2.57 (m, 1H), 1.81 - 1.80 (m, 1H), 1.19 (br, 3H).

Intermediate A19: (4aS,10bS)-8-(difluoromethoxy)-2,3,4,4a,6,10b-hexahydro-lH- pyrano[3,2-b:5,4-b']dipyridine

A19 Step-1: methyl 3-bromo-6-(difluoromethoxy)pyridine-2-carboxylate

[0952] To a stirred mixture of methyl 3-bromo-6-hydroxypyridine-2-carboxylate (10.00 g, 43.10 mmol) in DMF (100 mL) were added K2CO3 (11.91 g, 86.19 mmol) and sodium 2- chloro-2,2-difhioroacetate (7.88 g, 51.72 mmol) at room temperature under nitrogen atmosphere. The resulting mixture was stirred at 90 °C for 4 h under nitrogen atmosphere. The mixture was allowed to cool down to room temperature. The resulting mixture was diluted with water. The resulting mixture was extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SO4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-30% EtOAc in petroleum ether to afford methyl 3-bromo-6- (difhjoromethoxy)pyridine-2-carboxylate (9.58 g, 78%) as a white solid. MS ESI calculated for C₈H₆BrF₂NO3 [M+H]⁺, 281.95, 283.95; found, 282.05, 284.00. 'H NMR (400 MHz, DMSO-d₆) 5 8.33 (d, J = 8.8 Hz, 1H), 7.64 (t, J= 71.6 Hz, 1H), 7.28 (d, J = 8.8 Hz, 1H), 3.92 (s, 3H).

Step-2: methyl (E)-3-(5-((tert-butyldiphenylsilyl)oxy)pent-l-en-l-yl)-6- (difluoromethoxy)picolinate

[0953] To a stirred mixture of methyl 3-bromo-6-(difluoromethoxy)pyridine-2-carboxylate (9.58 g, 33.97 mmol) and tert-butyldiphenyl{ [(4E)-5-(4,4,5,5-tetramethyl-l,3,2- dioxaborolan-2-yl)pent-4-en-l-yl]oxy}silane (16.83 g, 33.36 mmol) in dioxane (100 mL) and H2O (10 mL) were added K2CO3 (9.39 g, 67.93 mmol) and Pd(dppf)Ch (2.49 g, 3.39 mmol) at room temperature under nitrogen atmosphere. The resulting mixture was stirred at 100 °C for 16 h under nitrogen atmosphere. The mixture was allowed to cool down to room temperature. The mixture was diluted with water and extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SO4. The residue was purified by silica gel column chromatography, eluted with 0-10% EtOAc in petroleum ether to afford methyl (E)-3-(5-((tert-butyldiphenylsilyl)oxy)pent-l-en-l-yl)-6- (difhjoromethoxy)picolinate (15.00 g, 84%) as a yellow oil. MS (ESI) calculated for C₂9H33F₂NO4Si [M+H]⁺, 526.21; found, 526.25.

Step-3: tert-butyl N-[(5S,6S)-6-{ 3-[(tert-butyldiphenylsilyl)oxy]propyl}-2- (difluoromethoxy)-8-oxo-5H,6H-pyrano[3,4-b]pyridin-5-yl]carbamate

[0954] To a stirred solution of B0CNH2 (10.35 g, 88.47 mmol) in n-PrOH (225 mL) was added a solution of NaOH (3.09 g, 77.04 mmol) in H2O (195 mL), then l,3-dichloro-5,5- dimethylimidazolidine-2, 4-dione (8.43 g, 42.81 mmol) was added to above mixture at room temperature under nitrogen atmosphere. After stirring for 30 min, a solution of (DHQ)2- PHAL (2.22 g, 2.85 mmol) in n-PrOH (30 mL) and a solution of methyl (E)-3-(5-((tert- butyldiphenylsilyl)oxy)pent-l-en-l-yl)-6-(difluoromethoxy)picolinate (15.00 g, 28.53 mmol) in n-PrOH (30 mL) were added sequentially. Then a solution of K2OSO4.2H2O (1.05 g, 2.85 mmol) and NaOH (0.4 N, 7 mL) was added dropwise at 0 °C. After that, the resulting mixture was stirred at room temperature for 16 h. The resulting mixture was diluted with water, and extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SO4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-16% EtOAc in petroleum ether to afford tert-butyl N-[(5S,6S)-6-{3-[(tert-butyldiphenylsilyl)oxy]propyl}-2- (difluoromethoxy)-8-oxo-5H,6H-pyrano[3,4-b]pyridin-5-yl]carbamate (5.90 g, 31%) as a yellow oil. MS ESI calculated for C33H4oF₂N206Si [M+H]⁺, 627.26; found, 627.35. 'H NMR (400 MHz, DMSO-de) 5 8.03 - 7.94 (m, 1H), 7.76 - 7.72 (m, 1H), 7.65 - 7.58 (m, 5H), 7.48 - 7.37 (m, 7H), 4.95 - 4.92 (m, 1H), 4.76 - 4.72 (m, 1H), 3.73 - 3.71 (m, 2H), 1.84 - 1.70 (m, 4H), 1.42 (s, 9H), 1.01 (s, 9H). Step-4: tert-butyl N-[(5S,6S)-6-{ 3-[(tert-butyldiphenylsilyl)oxy]propyl}-2- (difluoromethoxy)-5H,6H,8H-pyrano[3,4-b]pyridin-5-yl]carbamate

[0955] To a stirred mixture of tert-butyl N-[(5S,6S)-6-{3-[(tert- butyldiphenylsilyl)oxy]propyl}-2-(difluoromethoxy)-8-oxo-5H,6H-pyrano[3,4-b]pyridin-5- yl]carbamate (5.90 g, 9.41 mmol) in THF (60 mL) were added BFs-EtiO (10.69 g, 75.30 mmol) and NaBFU (2.85 g, 75.30 mmol) at 0 °C under nitrogen atmosphere. The resulting mixture was stirred at room temperature for 16 h under nitrogen atmosphere. The reaction was quenched with water, and extracted with EtOAc. The residue was purified by silica gel column chromatography, eluted with 0-11% EtOAc in petroleum ether to afford tert-butyl N- [(5S,6S)-6-{3-[(tert-butyldiphenylsilyl)oxy]propyl}-2-(difluoromethoxy)-5H,6H,8H- pyrano[3,4-b]pyridin-5-yl]carbamate (1.59 g, 27%) as a colorless oil. MS ESI calculated for C33H₄2F₂N2O5Si [M+H]⁺, 613.28; found, 613.35.

Step-5 : tert-butyl N- [(5S,6S)-2-(difluoromethoxy)-6-(3-hydroxypropyl)-5H,6H,8H- pyrano[3,4-b]pyridin-5-yl]carbamate

[0956] To a stirred mixture of tert-butyl N-[(5S,6S)-6-{3-[(tert- butyldiphenylsilyl)oxy]propyl}-2-(difluoromethoxy)-5H,6H,8H-pyrano[3,4-b]pyridin-5- yl]carbamate (1.59 g, 2.59 mmol) in THF (16 mL) was added TBAF (1.02 g, 3.89 mmol) at room temperature under nitrogen atmosphere. The resulting mixture was stirred at room temperature for 2 h. The resulting mixture was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-50% EtOAc in petroleum ether to afford tert-butyl N-[(5S,6S)-2-(difluoromethoxy)-6-(3-hydroxypropyl)- 5H,6H,8H-pyrano[3,4-b]pyridin-5-yl]carbamate (700 mg, 72%) as a colorless oil. MS ESI calculated for C17H24F2N2O5 [M+H]⁺, 375.17; found, 375.15. 'H NMR (400 MHz, DMSO- df>) 3 7.74 (d, 7 = 8.4 Hz, 1H), 7.65 (t, J = 72.8 Hz, 1H), 7.08 (d, J = 9.4 Hz, 1H), 6.96 (d, J =

8.4 Hz, 1H), 4.70 - 4.49 (m, 3H), 4.39 (t, J = 5.2 Hz, 1H), 3.73 - 3.61 (m, 1H), 3.49 - 3.38 (m, 2H), 1.62 - 1.51 (m, 4H), 1.40 (s, 9H).

Step-6: tert-butyl (4aS, 10bS)-8-(difluoromethoxy)-2,3,4,4a,6, 1 Ob-hexahydro- lH-pyrano[3,2- b:5,4-b']dipyridine- 1 -carboxylate

[0957] To a stirred mixture of tert-butyl N-[(5S,6S)-2-(difhioromethoxy)-6-(3- hydroxypropyl)-5H,6H,8H-pyrano[3,4-b]pyridin-5-yl]carbamate (700 mg, 1.87 mmol) in toluene (7 mL) was added CMBP (902 mg, 3.74 mmol) at room temperature under nitrogen atmosphere. The resulting mixture was stirred at 100 °C for 16 h. The mixture was allowed to cool down to room temperature. The resulting mixture was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-13% EtOAc in petroleum ether to afford tert-butyl (4aS,10bS)-8-(difhioromethoxy)-

2,3,4,4a,6,10b-hexahydro-lH-pyrano[3,2-b:5,4-b']dipyridine-l-carboxylate (570 mg, 85%) as a colorless oil. MS ESI calculated for C17H22F2N2O4 [M+H]⁺, 357.15; found, 357.20.

Step-7: (4aS,10bS)-8-(difhioromethoxy)-2,3,4,4a,6,10b-hexahydro-lH-pyrano[3,2-b:5,4- b']dipyridine hydrochloride (A19)

[0958] To a stirred mixture of tert-butyl (4aS,10bS)-8-(difhioromethoxy)-2,3,4,4a,6,10b- hexahydro-lH-pyrano[3,2-b:5,4-b']dipyridine-l -carboxylate (570 mg, 1.77 mmol) in DCM (3 mL) was added HC1 (4 M in 1,4-dioxane, 3 mL) dropwise at room temperature. The resulting mixture was stirred at room temperature for 1 h under nitrogen atmosphere. The resulting mixture was concentrated under reduced pressure to afford (4aS,10bS)-8-(difluoromethoxy)- 2,3,4,4a,6,10b-hexahydro-lH-pyrano[3,2-b:5,4-b']dipyridine hydrochloride (A19) (500 mg, 96% yield, 94% e.e.) as a white solid. MS ESI calculated for C12H14F2N2O2 [M+H]⁺, 257.10; found, 257.00. ¹H NMR (400 MHz, DMSO-d₆) 8 10.12 (d, J= 11.2 Hz, 1H), 8.78 - 8.75 (m, 1H), 8.17 (d, J = 8.4 Hz, 1H), 7.70 (t, J = 72.8 Hz, 1H), 7.11 (d, J = 8.4 Hz, 1H), 4.78 (s, 2H), 4.40 (d, J= 10.4 Hz, 1H), 4.06 - 4.05 (m, 1H), 3.23 - 2.99 (m, 2H), 2.02 - 1.99 (m, 1H), 1.93

- 1.77 (m, 2H), 1.70 - 1.66 (m, 1H). Absolute stereochemistry was determined by crystallography of a compound prepared using A19.

Intermediate A21: (2R,4aS,10bS)-8-chloro-2-methyl-l,2,3,4a,5,10b- hexahydrochromeno[3,4-b][l,4]oxazine hydrochloride (A21)

Step-1: 1:1 mixture of (S)-3-bromo-7-chloro-2,3-dihydro-l-benzopyran-4-one and (R)-3- bromo-7-chloro-2,3-dihydro-l-benzopyran-4-one

[0959] To a solution of 7-chloro-2,3-dihydro-l-benzopyran-4-one (50.00 g, 273.82 mmol) in Et2O (500 mL) was added Br2 (15.01 mL, 292.99 mmol) dropwise at 0 °C. The resulting mixture was stirred at room temperature for 1 h under nitrogen atmosphere. The mixture was allowed to cool down to 0 °C, then was quenched by the addition of sat. Na2SC>3 (aq.) at 0 °C. The precipitated solids were collected by filtration. The solids were purified by trituration with Et2O. The precipitated solids were collected and dried over vacuum to afford a 1: 1 mixture of (S)-3-bromo-7-chloro-2,3-dihydro-l-benzopyran-4-one and (R)-3-bromo-7- chloro-2,3-dihydro-l-benzopyran-4-one (63.00 g, 87%) as an off-white solid. MS (ESI) calculated for (C9H₆BrClO₂) [M+H]⁺, 260.92, 262.92; found, 261.00, 263.00.

Step-2: 1:1 mixture of (3S,4S)-3-bromo-7-chlorochroman-4-ol and (3R,4R)-3-bromo-7- chlorochroman-4-ol

[0960] To a solution of 3-bromo-7-chloro-2,3-dihydro-l-benzopyran-4-one (64.00 g, 244.74 mmol) in MeOH (1 L) was added NaBFU (4.63 g, 122.37 mmol) in portions at 0 °C. The resulting mixture was warmed at room temperature and stirred for 2 h. The reaction was quenched with water at 0 °C. The organic solvent was removed under vacuum. The precipitated solids were collected by filtration and washed with water. The solids were dried over vacuum to afford a 1:1 mixture of (3S,4S)-3-bromo-7-chlorochroman-4-ol and (3R,4R)- 3-bromo-7-chlorochroman-4-ol (63.00 g, 97%) as an off-white solid. MS (ESI) calculated for (C₉H₈BrClO2) [M+H]⁺, 262.94, 264.94; found, 263.00, 265.00. 'H NMR (400 MHz, DMSO- d₆) 5 7.32 (d, J= 8.4 Hz, 1H), 6.98 (dd, J = 8.4, 2.0 Hz, 1H), 6.86 (d, J= 2.0 Hz, 1H), 6.05 (d, J = 5.8 Hz, 1H), 4.90 - 4.79 (m, 1H), 4.71 - 4.68 (m, 1H), 4.58 - 4.54 (m, 1H), 4.34 (dd, J = 12.0, 6.0 Hz, 1H).

Step-3: 1:1 mixture of (3S,4S)-4-amino-7-chloro-3,4-dihydro-2H-l-benzopyran-3-ol and

(3R,4R)-4-amino-7-chloro-3,4-dihydro-2H-l-benzopyran-3-ol

[0961] To a solution of 3-bromo-7-chloro-3,4-dihydro-2H-l-benzopyran-4-ol (100.00 g, 379.47 mmol) in acetonitrile (1 L) was added cone. H2SO4 (74.43 g, 758.95 mmol) dropwise at 0 °C. The resulting mixture was heated at 50 °C for 2 h with stirring. The mixture was cooled at 0 °C, H₂O (I L) was added slowly to the mixture. The resulting mixture was stirred at 80 °C overnight. The resulting mixture was concentrated under reduced pressure to remove most of MeCN. The resulting mixture was filtered, the filter cake was washed with water. The filtrate was neutralized to pH 7 with NaOH (4 N). The precipitated solids were collected by filtration to afford a 1:1 mixture of (3S,4S)-4-amino-7-chloro-3,4-dihydro-2H-l- benzopyran-3-ol and (3R,4R)-4-amino-7-chloro-3,4-dihydro-2H-l-benzopyran-3-ol (81.00 g, 94%) as a white solid. MS (ESI) calculated for (C9H10CINO2) [M+H]⁺, 200.04; found, 200.00.

Step-4: 1:1 mixture of tert-butyl N-[(3S,4S)-7-chloro-3-hydroxy-3,4-dihydro-2H-l- benzopyran-4-yl] carbamate and tert-butyl N-[(3R,4R)-7-chloro-3-hydroxy-3,4-dihydro-2H-l- benzopyran-4-yl] carbamate

[0962] To solution of a 1:1 mixture of (3S,4S)-4-amino-7-chloro-3,4-dihydro-2H-l- benzopyran-3-ol and (3R,4R)-4-amino-7-chloro-3,4-dihydro-2H-l-benzopyran-3-ol (64.00 g, 320.59 mmol) in MeOH (1 L) was added TEA (97.33 g, 961.77 mmol), this was followed by the addition of BOC2O (76.97 g, 352.65 mmol) in portions at 0 °C. The resulting mixture was stirred at room temperature overnight. The resulting mixture was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-5% methanol in dichloromethane to afford a 1:1 mixture of tert-butyl N-[(3S,4S)-7-chloro-3- hydroxy-3,4-dihydro-2H-l-benzopyran-4-yl]carbamate and tert-butyl N-[(3R,4R)-7-chloro-3- hydroxy-3,4-dihydro-2H-l-benzopyran-4-yl]carbamate (52.00 g, 54%) as a white solid. MS (ESI) calculated for (C14H18CINO4) [M+H]⁺, 300.09; found, 300.05.

Step-5: 1:1 mixture of (S)-l-(((3S,4S)-4-amino-7-chlorochroman-3-yl)oxy)propan-2-ol and (S)- 1 -(((3R,4R)-4-amino-7-chlorochroman-3-yl)oxy)propan-2-ol [0963] To a solution of a 1 : 1 mixture of tert-butyl N-[(3S,4S)-7-chloro-3-hydroxy-3,4- dihydro-2H-l-benzopyran-4-yl] carbamate and tert-butyl N-[(3R,4R)-7-chloro-3-hydroxy-3,4- dihydro-2H-l-benzopyran-4-yl] carbamate (79.00 g, 263.55 mmol) in DCM (800 mL) were added NaOH (73.79 g, 1844.87 mmol) and tetrabutylazanium hydrogen sulfate (134.23 g, 395.32 mmol), then (4S)-4-methyl-l, 3, 2-X-6-dioxathiolane-2, 2-dione (supplier: Suzhou spark Biotechnology Co., Ltd. CAS# 174953-30-1) (54.61 g, 395.32 mmol) was added dropwise at room temperature. The mixture was stirred at room temperature for 3 h under nitrogen atmosphere. The resulting mixture was concentrated under reduced pressure. The residue was redissolved in water (800 mL), and cone. H2SO4 (258.47 g, 2635.53 mmol) was added slowly to the mixture at 0 °C. The resulting mixture was stirred at 60 °C overnight. The reaction mixture was cooled down to room temperature and neutralized with NaOH (aq.) to pH 7. The aqueous layer was extracted with DCM. The organic layer was dried over anhydrous sodium sulfate, filtered and concentrated under vacuum to afford a 1:1 mixture of (S)-l-(((3S,4S)-4- amino-7-chlorochroman-3-yl)oxy)propan-2-ol and (S)-l-(((3R,4R)-4-amino-7- chlorochroman-3-yl)oxy)propan-2-ol (60.00 g, crude) as a yellow solid, which was used directly. MS (ESI) calculated for (C12H16CINO3) [M+H]⁺, 258.08; found, 258.05.

Step-6: 1:1 mixture of tert-butyl ((3S,4S)-7-chloro-3-((S)-2-hydroxypropoxy)chroman-4- yl)carbamate and tert-butyl ((3R,4R)-7-chloro-3-((S)-2-hydroxypropoxy)chroman-4- yl)carbamate

[0964] To a solution of a 1:1 mixture of (S)-l-(((3S,4S)-4-amino-7-chlorochroman-3- yl)oxy)propan-2-ol and (S)-l-(((3R,4R)-4-amino-7-chlorochroman-3-yl)oxy)propan-2-ol (60.00 g, 232.82 mmol) in methanol (600 mL) was added di-tert-butyl dicarbonate (60.98 g, 279.38 mmol), the mixture was stirred at room temperature overnight. The resulting mixture was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-10% ethyl acetate in petroleum ether to afford a 1:1 mixture of tert-butyl ((3S,4S)-7-chloro-3-((S)-2-hydroxypropoxy)chroman-4-yl)carbamate and ert- butyl ((3R,4R)-7-chloro-3-((S)-2-hydroxypropoxy)chroman-4-yl)carbamate (28.00 g, 30% over two steps) as a white solid. MS (ESI) calculated for (C17H24CINO5) [M+H]⁺, 358.13; found, 358.05.

Step-7 : tert-butyl (2R,4aS , 10bS)-8-chloro-2-methyl-2,3 ,4a, 1 Ob-tetrahydrochromeno [3 ,4- b][ 1,4] oxazine- l(5H)-carboxylate, isomer 1 and tert-butyl (2R,4aR,10bR)-8-chloro-2-methyl-2,3,4a,10b-tetrahydrochromeno[3,4- b][ 1,4] oxazine- l(5H)-carboxylate, isomer 2

[0965] To a solution of a 1 : 1 mixture of tert-butyl ((3S,4S)-7-chloro-3-((S)-2- hydroxypropoxy)chroman-4-yl)carbamate and tert-butyl ((3R,4R)-7-chloro-3-((S)-2- hydroxypropoxy)chroman-4-yl)carbamate (28.00 g, 78.24 mmol) in anhydrous toluene (280 mL) was added 2-(tributyl-k⁵-phosphaneylidene)acetonitrile (28.33 g, 117.37 mmol) (CAS No. 157141-27-0) at 0 °C. The resulting mixture was stirred at 110 °C overnight under nitrogen atmosphere. The resulting mixture was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-10% ethyl acetate in petroleum ether to afford tert-butyl (2R,4aS,10bS)-8-chloro-2-methyl-2,3,4a,10b- tetrahydrochromeno[3,4-b][l,4]oxazine-l(5H)-carboxylate, isomer 1 (9.00 g, 34%) as a colorless oil as the second eluting peak. The stereochemistry was confirmed by NOE. MS (ESI) calculated for (C17H22CINO4) [M+H]⁺, 340.12; found, 340.10. ’H NMR (300 MHz, DMSO-d₆) 8 7.09 - 6.92 (m, 2H), 6.85 (s, 1H), 5.24 - 5.14 (m, 1H), 4.35 - 4.25 (m, 2H), 4.07 - 4.00 (m, 1H), 3.82 - 3.80 (m, 1H), 3.72 - 3.61 (m, 2H), 1.51 (s, 9H), 0.78 - 0.62 (m, 3H).

[0966] The purification also afford tert-butyl (2R,4aR,10bR)-8-chloro-2-methyl- 2,3,4a,10b-tetrahydrochromeno[3,4-b][l,4]oxazine-l(5H)-carboxylate, isomer 2 (11.20 g, 42%) as a colorless oil as the first eluting peak. MS (ESI) calculated for (C17H22CINO4) [M+H]⁺, 340.12; found, 340.10. 'H NMR (300 MHz, DMSO-d₆) 3 7.00 - 6.99 (m, 2H), 6.87 (s, 1H), 5.25 - 5.24 (m, 1H), 4.33 - 4.22 (m, 3H), 3.54 - 3.50 (m, 2H), 3.40 - 3.34 (m, 1H), 1.49 (s, 9H), 1.35 - 1.33 (m, 3H).

Step-8 : (2R,4aS, 10bS)-8-chloro-2-methyl- 1 ,2, 3, 4a, 5, 10b-hexahydrochromeno[3,4- b][ 1,4] oxazine hydrochloride (A21)

A21

[0967] To a solution of tert-butyl (2R,4aS,10bS)-8-chloro-2-methyl-2,3,4a,10b- tetrahydrochromeno[3,4-b][l,4]oxazine-l(5H)-carboxylate, isomer 1 (9.00 g, 26.49 mmol) in 1,4-dioxane (100 mL) was added HC1 (10 mL, 4M in dioxane), the mixture was stirred at 25 °C for 1 h. The resulting mixture was concentrated under reduced pressure to afford (2R,4aS, 10bS)-8-chloro-2-methyl-l ,2, 3, 4a, 5, 10b-hexahydrochromeno[3,4-b] [1 ,4]oxazine hydrochloride (A21) (6.00 g, 96%) as a white solid. MS (ESI) calculated for (C12H14CINO2) [M+H]⁺, 240.07; found, 240.10. 'H NMR (300 MHz, DMSO-d₆) 8 10.81 (br, 1H), 9.67 (br, 1H), 7.79 (d, J = 8.4 Hz, 1H), 7.10 (d, J= 8.4 Hz, 1H), 7.02 (s, 1H), 4.80 - 4.72 (m, 2H), 4.48 - 4.41 (m, 1H), 4.23 - 4.18 (m, 1H), 3.87 - 3.81 (m, 1H), 3.59 - 3.52 (m, 2H), 1.20 (d, J = 6.0 Hz, 3H).

Intermediate A22: (2R,4aS,10bS)-8-(difluoromethoxy)-2-methyl-l,2,3,4a,5,10b- hexahydrochrotneno[3,4-b] [ 1 ,4]oxazine (A22)

A22 Step-1 : 7-(difluoromethoxy)-2,3-dihydro- 1 -benzopyran-4-one

[0968] To a stirred solution of 7-hydroxy-2,3-dihydro-l-benzopyran-4-one (50.10 g, 304.58 mmol) in DCM (100 mL) was added 20% w/w KOH aqueous solution (102.53 g, 1.82 mol) at 0 °C. Then (bromodifhioromethyl)trimethylsilane (123.72 g, 609.16 mmol) was added dropwise at 0 °C under nitrogen atmosphere. The resulting mixture was stirred at room temperature for 2 h. The reaction mixture was extracted with DCM. The combined organic layers were washed with brine, dried over anhydrous Na2SO4. After filtration, the filtrate was concentrated under reduced pressure. The resulting residue was purified by normal phase flash chromatography with a 330 g silica gel column and eluted with 0-30% ethyl acetate in petroleum ether to afford 7-(difluoromethoxy)-2,3-dihydro-l-benzopyran-4-one (40.60 g, 62%) as a yellow oil. MS ESI calculated for C10H8F2O3 [M+H]⁺, 215.04; found, 215.05. 'H NMR (400 MHz, DMSO-J₆) 8 7.81 (d, J= 8.6 Hz, 1H), 7.40 (t, 7 = 73.2 Hz, 1H), 7.01 - 6.77 (m, 2H), 4.57 (t, J = 6.4 Hz, 2H), 2.79 (t, J = 6.4 Hz, 2H).

Step-2: 1:1 mixture of (S)-3-bromo-7-(difluoromethoxy)-2,3-dihydro-l-benzopyran-4-one and (R)-3-bromo-7-(difluoromethoxy)-2,3-dihydro-l-benzopyran-4-one

[0969] To a stirred solution of 7-(difluoromethoxy)-2,3-dihydro-l-benzopyran-4-one (34.10 g, 158.75 mmol) in Diethyl ether (340 mL) was added B (8.1 mL, 158.08 mmol) dropwise at 0 °C under nitrogen atmosphere. The mixture was stirred at room temperature for 1 h. The reaction mixture was quenched by NaS2Os (sat.) and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under vacuum. The resulting residue was purified by normal phase flash column chromatography with a 330 g silica gel column and eluted with 0-30% ethyl acetate in petroleum ether within 20 min to afford a 1: 1 mixture of (S)-3-bromo-7- (difluoromethoxy)-2,3-dihydro- l-benzopyran-4-one and (R)-3-bromo-7-(difluoromethoxy)- 2,3-dihydro-l-benzopyran-4-one (41.35 g, 75%) as a yellow solid. MS ESI calculated for Ci₀H₇BrF₂O3 [M+H]⁺, 292.95; found, 292.80. 'H NMR (400 MHz, DMSO-d₆) 87.90 (d, J = 8.6 Hz, 1H), 7.46 (t, J = 73.0 Hz, 1H), 6.95 (d, J = 8.6 Hz, 2H), 5.02 (t, J = 3.2 Hz, 1H), 4.90 (dd, J = 13.4, 2.8 Hz, 1H), 4.67 (dd, J= 13.4, 3.8 Hz, 1H).

Step-3: 1:1 mixture of (3S,4S)-3-bromo-7-(difhioromethoxy)chroman-4-ol and (3R,4R)-3- bromo-7-(difluoromethoxy)chroman-4-ol

[0970] To a stirred solution of a 1:1 mixture of (S)-3-bromo-7-(difluoromethoxy)-2,3- dihydro- l-benzopyran-4-one and (R)-3-bromo-7-(difluoromethoxy)-2,3-dihydro- 1- benzopyran-4-one (41.30 g, 141.43 mmol) in EtOH (400 mL) was added NaBH4 (2.82 g, 70.72 mmol) in portions at 0 °C. The resulting mixture was stirred at room temperature for 1 h. The reaction mixture was quenched by water at 0 °C. The EtOH was removed under vacuum. The remaining aqueous solution was extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate and concentrated under vacuum to afford a 1:1 mixture of (3S,4S)-3-bromo-7-(difluoromethoxy)chroman-4-ol and (3R,4R)-3-bromo-7-(difluoromethoxy)chroman-4-ol (42.50 g, crude) as a white solid, which was used without further purification. MS ESI calculated for CioHgBrFzOs [M+H]⁺, 294.97, 296.97; found, 294.97, 296.97.

Step-4: 1:1 mixture of (3S,4S)-4-amino-7-(difhioromethoxy)chroman-3-ol and (3R,4R)-4- amino-7-(difhioromethoxy)chroman-3-ol [0971] To a mixture of a 1:1 mixture of (3S,4S)-3-bromo-7-(difluoromethoxy)chroman-4- ol and (3R,4R)-3-bromo-7-(difluoromethoxy)chroman-4-ol (42.50 g, 183.98 mmol) in ACN (430 mL) was added H2SO4 (cone.) (36.06 g, 367.96 mmol) at 0 °C. The resulting mixture was stirred at 50 °C for 2 h. Then the mixture was cooled down to room temperature, then H2O (400 mL) was added to the mixture. The resulting mixture was stirred at 75 °C for 12 h. The organic solvent was removed under reduced pressure. The resulting aqueous layers was basified with NaOH (aq., 25%) to pH 12. The precipitated solids were collected by filtration and fried under vacuum to afford the product. The filtrate was extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under vacuum to afford another batch of product. The workup was totally afford a 1:1 mixture of (3S,4S)-4-amino-7-(difluoromethoxy)chroman-3-ol and (3R,4R)-4-amino-7-(difluoromethoxy)chroman-3-ol (28.50 g, 65%) as a white solid. MS ESI calculated for C10H11F2NO3 [M+H]⁺, 232.07; found, 232.00.

Step-5: 1:1 mixture of tert-butyl N-[(3S, 4S)-7-(difhioromethoxy )-3-hydroxy-3, 4-dihydro-2H- l-benzopyran-4-yl] carbamate and tert-butyl N-[(3R,4R)-7-(difluoromethoxy)-3-hydroxy-3,4- dihydro-2H- 1 -benzopyran-4-yl] carbamate

[0972] To a stirred solution of a 1:1 mixture of (3S,4S)-4-amino-7- (difhioromethoxy)chroman-3-ol and (3R,4R)-4-amino-7-(difluoromethoxy)chroman-3-ol (28.50 g, 122.84 mmol) in MeOH (300 mL) were sequentially added TEA (18.61 g, 184.27 mmol) and BOC2O (29.45 g, 135.12 mmol) at room temperature. The resulting solution was stirred at room temperature for 16 h. The resulting mixture was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-50% ethyl acetate in petroleum ether to afford a 1:1 mixture of tert-butyl N-[(3S,4S)-7- (difluoromethoxy)-3-hydroxy-3,4-dihydro-2H-l-benzopyran-4-yl]carbamate and tert-butyl N-[(3R,4R)-7-(difluoromethoxy)-3-hydroxy-3,4-dihydro-2H-l-benzopyran-4-yl]carbamate (19.78 g, 50%) as a white solid. MS ESI calculated for C15H19F2NO5 [M+H]⁺, 332.12; found, 332.00. Step-6: 1:1 mixture of tert-butyl ((3S,4S)-7-(difluoromethoxy)-3-((S)-2- hydroxypropoxy)chroman-4-yl)carbamate and tert-butyl ((3R,4R)-7-(difluoromethoxy)-3- ((S)-2-hydroxypropoxy)chroman-4-yl)carbamate

[0973] To a mixture of a 1: 1 mixture of tert-butyl N-[(3S,4S)-7-(difluoromethoxy)-3- hydroxy-3,4-dihydro-2H-l-benzopyran-4-yl]carbamate and tert-butyl N-[(3R,4R)-7- (difluoromethoxy)-3-hydroxy-3,4-dihydro-2H-l-benzopyran-4-yl]carbamate (19.50 g, 60.56 mmol) in DCM (200 mL) were added NaOH (14.53 g, 363.3 mmol), tetrabutylazanium hydrogen sulfate (4.10 g, 12.11 mmol) and (4S)-4-methyl- 1,3, 2- -6-dioxathiolane-2, 2-dione (supplier: Suzhou spark Biotechnology Co., Ltd. CAS# 174953-30-1) (10.28 g, 72.62 mmol) at room temperature. The mixture was stirred at room temperature for 2 h. Then the solvents were evaporated under vacuum and the residue was diluted with water. Then the aqueous solution was acidified with HC1 (2N) to PH~7 and extracted with ethyl acetate. The combined organic layers were concentrated under vacuum. The residual was dissolved with tBuOMe (800 mL), then H2O (32 mL) and a solution of pTsOH (2.08 g, 12.11 mmol) in 1,4-dioxane (320 mL) were added. The resulting mixture was stirred at 40 °C for 16 h. The reaction mixture was diluted by water and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under vacuum. The resulting residue was purified by normal phase flash chromatography with a 330 g silica gel column and eluted with 0-70% ethyl acetate in petroleum ether to afford a 1:1 mixture of tert-butyl ((3S,4S)-7-(difluoromethoxy)-3-((S)-2- hydroxypropoxy)chroman-4-yl)carbamate and tert-butyl ((3R,4R)-7-(difluoromethoxy)-3- ((S)-2-hydroxypropoxy)chroman-4-yl)carbamate (14.43 g, 63%) as a white solid. MS ESI calculated for C18H25F2NO6 [M+H]⁺, 390.16; found, 390.10.

Step-7: tert-butyl (2R,4aS,10bS)-8-(difluoromethoxy)-2-methyl-2,3,4a,10b- tetrahydrochromeno[3,4-b][l,4]oxazine-l(5H)-carboxylate, isomer 1:

tert-butyl (2R,4aR,10bR)-8-(difluoromethoxy)-2-methyl-2,3,4a,10b-tetrahydrochromeno[3,4- b][ 1,4] oxazine- l(5H)-carboxylate, isomer 2:

[0974] To a mixture of a 1: 1 mixture of tert-butyl ((3S,4S)-7-(difluoromethoxy)-3-((S)-2- hydroxypropoxy)chroman-4-yl)carbamate and tert-butyl ((3R,4R)-7-(difluoromethoxy)-3- ((S)-2-hydroxypropoxy)chroman-4-yl)carbamate (14.43 g, 37.11 mmol) in toluene (200 mL) was added 2-(tributyl- ⁵-phosphaneylidene)acetonitrile (17.89 g, 74.23 mmol) (CAS No. 157141-27-0). The mixture was stirred at 110 °C for 1 h under nitrogen atmosphere. The solvents were moved under vacuum. The residue was dissolved with ethyl acetate and washed with water. The combined organic layers dried over anhydrous sodium sulfate, filtered, and concentrated under vacuum. The resulting residue was purified by normal phase flash column chromatography with a 330 g silica gel column and eluted with 0-50% ethyl acetate in petroleum ether to afford tert-butyl (2R,4aS,10bS)-8-(difluoromethoxy)-2-methyl- 2,3,4a,10b-tetrahydrochromeno[3,4-b][l,4]oxazine-l(5H)-carboxylate, isomer 1 (3.16 g, 22%) as a yellow solid with the second eluting peak. The stereochemistry was confirmed by NOE. MS ESI calculated for C18H23F2NO5 [M+H]⁺, 372.15; found, 372.05.

[0975] The purification also afford tert-butyl (2R,4aR,10bR)-8-(difluoromethoxy)-2- methyl-2,3,4a,10b-tetrahydrochromeno[3,4-b][l,4]oxazine-l(5H)-carboxylate, isomer 2 (3.30 g, 24%) as a yellow solid with the first eluting peak. The stereochemistry was confirmed by NOE. MS ESI calculated for C18H23F2NO5 [M+H]⁺, 372.15; found, 372.05. Step-8: (2R,4aS,10bS)-8-(difluoromethoxy)-2-methyl-l,2,3,4a,5,10b- hexahydrochromeno[3,4-b] [ 1 ,4]oxazine (A22)

[0976] To a stirred solution of tert-butyl (2R,4aS,10bS)-8-(difluoromethoxy)-2-methyl- 2,3,4a,10b-tetrahydrochromeno[3,4-b][l,4]oxazine-l(5H)-carboxylate, isomer 1 (6.8 g, 18.31 mmol) in DCM (68 mL) was added Zinc bromide (8.25 g, 36.62 mmol) at 25 °C. The resulting solution was stirred at 40 °C for 2 h. The mixture was concentrated under vacuum. The residue was diluted by water and was extracted with EtOAc. The combined organic layers were washed with brine, then dried over anhydrous Na2SC>4. After filtration, the filtrate was concentrated under reduced pressure to afford (2R,4aS,10bS)-8-(difluoromethoxy)-2- methyl-l,2,3,4a,5,10b-hexahydrochromeno[3,4-b][l,4]oxazine (A22) (4.6 g, 73%) as a yellow solid. MS ESI calculated for C13H15F2NO3 [M+H]⁺, 272.10; found, 272.05. 'H NMR (400 MHz, DMSO-de) 5 (ppm) 7.45 - 6.98 (m, 2H), 6.71 (dd, J = 8.4, 2.4 Hz, 1H), 6.59 (d, J = 2.4 Hz, 1H), 4.65 (t, J = 11.2 Hz, 1H), 4.02 - 3.94 (m, 2H), 3.88 - 3.84 (m, 1H), 3.48 (dd, J = 10.8, 3.2 Hz, 1H), 3.16 (t, J = 10.4 Hz, 1H), 2.99 - 2.89 (m, 1H), 2.59 (s, 1H), 0.87 (d, J = 6.4 Hz, 3H).

Intermediate A23, isomer 1: rel-(4bS,8aS)-2-(difluoromethoxy)-4b,6,7,8,8a,9-hexahydro- 5H-cyclopenta[l,2-b:3,4-b']dipyridine, isomer 1:

A23, isomer 1 . _an(^ Intermediate A23, isomer 2: rel-(4bR,8aR)-2-(difluoromethoxy)-4b,6,7,8,8a,9-hexahydro- 5H-cyclopenta[l,2-b:3,4-b']dipyridine, isomer 2

Step 1 : 2-hydroxy-6H,7H-cyclopenta[b]pyridin-5-one

[0977] A mixture of ethyl 2-chloro-5-oxo-6H,7H-cyclopenta[b]pyridine-6-carboxylate (60.00 g, 250.36 mmol) and H3PO4 (600 mL) was stirred at 180 °C for 3 h under nitrogen atmosphere. After cooling down, the mixture was poured into ice/water, and neutralized with NaOH (aq.) to pH 6-7. The resulting mixture was extracted with EtOAc, and the combined organic layers were concentrated under reduced pressure to afford 2-hydroxy-6H,7H- cyclopenta[b]pyridin-5-one (100 g, crude) as a yellow solid. MS ESI calculated for C8H7NO2 [M+H]⁺, 150.05; found, 150.00.

Step 2: 2-(difluoromethoxy)-6H,7H-cyclopenta[b]pyridin-5-one

[0978] To a stirred mixture of 2-hydroxy-6H,7H-cyclopenta[b]pyridin-5-one (11.60 g, 77.77 mmol) and K2CO3 (32.25 g, 233.32 mmol) in DMF (150 mL) was added sodium 2- chloro-2,2-difhioroacetate (17.79 g, 116.66 mmol) in portions at room temperature. The resulting mixture was stirred at 90 °C for 4 h. After cooling down, the mixture was poured into water. The mixture was extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SO4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-50% ethyl acetate in petroleum ether to afford 2- (difluoromethoxy)-6H,7H-cyclopenta[b]pyridin-5-one (3.10 g, 30% over two steps) as a yellow solid. MS ESI calculated for C9H7F2NO2 [M+H]⁺, 200.04; found, 200.15.

Step 3: 1:1 mixture of tert-butyl (S)-(3-(2-(difluoromethoxy)-5-oxo-6,7-dihydro-5H- cyclopenta[b]pyridin-6-yl)propyl)carbamate and tert-butyl (R)-(3-(2-(difluoromethoxy)-5- oxo-6, 7-dihydro-5H-cyclopenta[b]pyridin-6-yl)propyl)carbamate

[0979] To a stirred solution of 2-(difluoromethoxy)-6H,7H-cyclopenta[b]pyridin-5-one (13.00 g, 65.28 mmol) and tert-butyl N-(3-hydroxypropyl)carbamate (34.31 g, 195.83 mmol) in toluene (200 mL) were added t-BuOLi (1.05 g, 13.06 mmol) and dichloro(pentamethylcyclopentadienyl)ruthenium(III) polymer (2.01 g, 3.26 mmol). The resulting mixture was stirred at 110 °C for 2 h under nitrogen atmosphere. The resulting mixture was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-50% ethyl acetate in petroleum ether to afford a 1:1 mixture of tert-butyl (S)-(3-(2-(difhioromethoxy)-5-oxo-6,7-dihydro-5H- cyclopenta[b]pyridin-6-yl)propyl)carbamate and tert-butyl (R)-(3-(2-(difluoromethoxy)-5- oxo-6, 7-dihydro-5H-cyclopenta[b]pyridin-6-yl)propyl)carbamate (6.90 g, 30%) as a yellow oil. MS ESI calculated for C17H22F2N2O4 [M+H]⁺, 357.15; found, 357.20.

Step 4: 1:1 mixture of (S)-2-(difluoromethoxy)-7,8,8a,9-tetrahydro-6H-cyclopenta[l,2-b:3,4- b']dipyridine and (R)-2-(difluoromethoxy)-7,8,8a,9-tetrahydro-6H-cyclopenta[l,2-b:3,4- b']dipyridine [0980] To a solution of a 1:1 mixture of tert-butyl (S)-(3-(2-(difluoromethoxy)-5-oxo-6,7- dihydro-5H-cyclopenta[b]pyridin-6-yl)propyl)carbamate and tert-butyl (R)-(3-(2- (difluoromethoxy)-5-oxo-6,7-dihydro-5H-cyclopenta[b]pyridin-6-yl)propyl)carbamate (4.00 g, 11.22 mmol) in DCM (30 mL) was added trifluoroacetic acid (15 mL). The mixture was stirred at room temperature for 2 h. The resulting mixture was concentrated under reduced pressure. The residue was dissolved in DCM (40 mL), and 4 A molecular sieves (1 g) was added. The resulting mixture was stirred at room temperature for 16 h. The resulting mixture was filtered, and the filter cake was washed with DCM. The filtrate was concentrated under reduced pressure to afford a 1:1 mixture of (S)-2-(difluoromethoxy)-7,8,8a,9-tetrahydro-6H- cyclopenta[l,2-b:3,4-b']dipyridine and (R)-2-(difluoromethoxy)-7,8,8a,9-tetrahydro-6H- cyclopenta[l,2-b:3,4-b']dipyridine (4.70 g, crude) as a yellow oil, which was used directly without purification. MS ESI calculated for C12H12F2N2O [M+H]⁺, 239.09; found, 239.05.

Step 5: 2:2:3:3 mixture of tert-butyl (4bR,8aS)-2-(difhioromethoxy)-4b,6,7,8,8a,9-hexahydro- 5H-cyclopenta[l ,2-b:3,4-b']dipyridine-5-carboxylate, tert-butyl (4bS,8aR)-2- (difluoromethoxy)-4b,6,7,8,8a,9-hexahydro-5H-cyclopenta[l,2-b:3,4-b']dipyridine-5- carboxylate, tert-butyl (4bS,8aS)-2-(difluoromethoxy)-4b,6,7,8,8a,9-hexahydro-5H- cyclopenta[l,2-b:3,4-b']dipyridine-5-carboxylate, and tert-butyl (4bR,8aR)-2- (difhioromethoxy)-4b,6,7,8,8a,9-hexahydro-5H-cyclopenta[l,2-b:3,4-b']dipyridine-5- carboxylate

[0981] To a stirred solution of a 1:1 mixture of (S)-2-(difluoromethoxy)-7,8,8a,9- tetrahydro-6H-cyclopenta[l,2-b:3,4-b']dipyridine and (R)-2-(difhioromethoxy)-7,8,8a,9- tetrahydro-6H-cyclopenta[l,2-b:3,4-b']dipyridine (4.70 g, crude) in methanol (47 mL) was added Pd/C (400 mg, 10%) at room temperature. The resulting mixture was stirred at room temperature for 16 h under hydrogen atmosphere. The resulting mixture was filtered. TEA (2.43 g, 24.07 mmol) and di-tert-butyl dicarbonate (3.95 g, 18.11 mmol) were added to the filtrate at 0 °C. The resulting mixture was stirred at room temperature for 1.5 h. The reaction solution was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-25% ethyl acetate in petroleum ether to afford a 2:2:3:3 mixture of tert-butyl (4bR,8aS)-2-(difluoromethoxy)-4b,6,7,8,8a,9-hexahydro-5H- cyclopenta[l,2-b:3,4-b']dipyridine-5-carboxylate, tert-butyl (4bS,8aR)-2-(difluoromethoxy)- 4b,6,7,8,8a,9-hexahydro-5H-cyclopenta[l,2-b:3,4-b']dipyridine-5-carboxylate, tert-butyl (4bS,8aS)-2-(difluoromethoxy)-4b,6,7,8,8a,9-hexahydro-5H-cyclopenta[l,2-b:3,4- b']dipyridine-5-carboxylate, and tert-butyl (4bR,8aR)-2-(difluoromethoxy)-4b,6,7,8,8a,9- hexahydro-5H-cyclopenta[l,2-b:3,4-b']dipyridine-5-carboxylate (2.20 g, 57% over two steps) as a colorless oil. MS ESI calculated for C17H22F2N2O3 [M+H]⁺, 341.16; found, 341.15.

Step 6: rel-(4bS,8aS)-2-(difluoromethoxy)-4b,6,7,8,8a,9-hexahydro-5H-cyclopenta[l,2-b:3,4- b']dipyridine, isomer 1 (A23, isomer 1):

A23, isomer 1 . _an(^ rel-(4bR,8aR)-2-(difluoromethoxy)-4b,6,7,8,8a,9-hexahydro-5H-cyclopenta[l,2-b:3,4- b']dipyridine, isomer 2 (A23, isomer 2)

A23, isomer 2

[0982] To a stirred solution of a 2:2:3:3 mixture of tert-butyl (4bR,8aS)-2- (difluoromethoxy)-4b,6,7,8,8a,9-hexahydro-5H-cyclopenta[l,2-b:3,4-b^,]dipyridine-5- carboxylate, tert-butyl (4bS,8aR)-2-(difluoromethoxy)-4b,6,7,8,8a,9-hexahydro-5H- cyclopenta[l,2-b:3,4-b']dipyridine-5-carboxylate, tert-butyl (4bS,8aS)-2-(difluoromethoxy)- 4b,6,7,8,8a,9-hexahydro-5H-cyclopenta[l,2-b:3,4-b^,]dipyridine-5-carboxylate, and tert-butyl (4bR,8aR)-2-(difluoromethoxy)-4b,6,7,8,8a,9-hexahydro-5H-cyclopenta[l,2-b:3,4- b']dipyridine-5-carboxylate(2.20 g, 6.46 mmol) in DCM (11 mL) was added HC1 (4 M in 1,4- dioxane, 11 mL) at room temperature. The resulting mixture was stirred at room temperature for 2 h. The reaction mixture was concentrated under reduced pressure. The residue was dissolved in water. The mixture was basified with saturated NaHCCh (aq.) to pH 8. The mixture was extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SO4. After filtration, the filtrate was concentrated under reduced pressure to afford a mixture product (1.45 g, 93%) as a colorless oil.

[0983] The mixture product (2.16 g) was separated by Prep-Achiral-SFC with the following conditions: [Column: DAICEL DCpak P4VP 3*25 cm, 5 pm; Mobile Phase A: CO2, Mobile Phase B: MeOH(20mM NHa-MeOH); Flow rate: 60 rnL/min; Gradient: isocratic 20% B; Column Temperature(°C): 35; Back Pressure(bar): 100; Wave Length: 254 nm; RTl(min): 3.90; RT2(min): 5.13; Sample Solvent: MEOH; Injection Volume: 1 mL; Number Of Runs: 7.0] to afford fraction A (786 mg, 36%) with the first peak on Achiral SFC, which was trans racemic based on NOESY.

[0984] The Achiral resolution also afford fraction B (1.17 g, 54%) with the second peak on Achiral SFC, which was cis racemic based on NOESY.

[0985] The fraction B (130 mg) was separated by Prep-Chiral-HPLC with the following conditions: [Column: CHIRALPAK IF, 2*25 cm, 5 pm; Mobile Phase A: Hex(0.5% 2M NH3-MeOH), Mobile Phase B: MeOH: DCM=1: 1; Flow rate: 20 mL/min; Gradient: 10% B to 10% B in 12 min; Wave Length: 220/254 nm; RTl(min): 9.09; RT2(min): 10.65; Sample Solvent: EtOH: DCM=1 : 1— HPLC; Injection Volume: 0.25 mL; Number Of Runs: 15] to afford (4bS,8aS)-2-(difluoromethoxy)-4b,6,7,8,8a,9-hexahydro-5H-cyclopenta[l,2-b:3,4- b']dipyridine, isomer 1 (A23, isomer 1) (50 mg) as a yellow oil. MS ESI calculated for C12H14F2N2O [M+H]⁺, 241.11; found, 241.10. 'H NMR (400 MHz, DMSO-^e) 87.75 (d, J = 8.0 Hz, 1H), 7.66 (t, J = 73.2 Hz, 1H), 6.84 (d, J = 8.0 Hz, 1H), 4.16 (d, J = 5.6 Hz, 1H), 2.88 - 2.79 (m, 1H), 2.66 - 2.54 (m, 2H), 2.49 - 2.41 (m, 1H), 2.40 - 2.31 (m, 1H), 1.75 - 1.65 (m, 1H), 1.44 - 1.20 (m, 3H). Absolute stereochemistry was not determined.

[0986] The chiral resolution of fraction B also afford (4bR,8aR)-2-(difluoromethoxy)- 4b,6,7,8,8a,9-hexahydro-5H-cyclopenta[l,2-b:3,4-b']dipyridine, isomer 2 (A23, isomer 2) (40 mg) as a yellow oil with the second peak on chiral HPLC. MS ESI calculated for C12H14F2N2O [M+H]⁺, 241.11; found, 241.10. ’H NMR (400 MHz, DMSO-d₆) 8 7.75 (d, J = 8.0 Hz, 1H), 7.66 (t, J = 73.2 Hz, 1H), 6.84 (d, J = 8.0 Hz, 1H), 4.16 (d, J = 5.6 Hz, 1H), 2.88 - 2.79 (m, 1H), 2.66 - 2.54 (m, 2H), 2.49 - 2.41 (m, 1H), 2.40 - 2.31 (m, 1H), 1.75 - 1.65 (m, 1H), 1.44 - 1.20 (m, 3H). Absolute stereochemistry was not determined.

Intermediate A24, isomer 1: (4aS,10bS)-8-(difluoromethoxy)-2,3,4,4a,6,10b-hexahydro- lH-isochromeno[4,3-b]pyridine, isomer 1:

A24, isomer

Intermediate A24, isomer 2: (4aR,10bR)-8-(difluoromethoxy)-2,3,4,4a,6,10b-hexahydro- lH-isochromeno[4,3-b]pyridine, isomer 2:

A24, isomer 2

Step 1: methyl 2-bromo-5-(difluoromethoxy)benzoate

[0987] To a stirred solution of methyl 2-bromo-5-hydroxybenzoate (120.00 g, 519.48 mmol) in DMF (500 mL) were added K2CO3 (215.06 g, 1558.44 mmol) and sodium 2- chloro-2,2-difhioroacetate (236.88 g, 1558.44 mmol) at 0 °C. The resulting solution was stirred at 100 °C for 2 h under nitrogen atmosphere. The resulting mixture was diluted with water. The resulting mixture was extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous NazSC . The resulting mixture was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with PE / EtOAc (5/1) to afford methyl 2-bromo-5-(difluoromethoxy)benzoate (75.70 g, 78%) as a yellow solid. MS (ESI) calculated for (C9H₇BrF₂O₃) [M+H]⁺, 280.95, 282.95; found, 280.95, 283.00.

Step 2: methyl 5-(difluoromethoxy)-2-(4,4,5,5-tetramethyl-l,3,2-dioxaborolan-2-yl)benzoate

O Bpin

[0988] To a stirred solution of methyl 2-bromo-5-(difluoromethoxy)benzoate (75.70 g, 270.41 mmol) in 1,4-dioxane (760 mL) were added BPD (103.00 g, 405.62 mmol), AcOK (79.62 g, 811.24 mmol) and Pd(dppf)Cl₂ (19.79 g, 27.04 mmol). The resulting mixture was stirred at 80 °C for 16 h under nitrogen atmosphere. The resulting mixture was filtered, the filter cake was washed with ethyl acetate. The filtrate was concentrated under reduced pressure. The resulting mixture was diluted with water. The resulting mixture was extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na₂SO4. The resulting mixture was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with PE / EtOAc (5/1) to afford methyl 5-(difhioromethoxy)-2-(4,4,5,5-tetramethyl-l,3,2-dioxaborolan-2-yl)benzoate (72.60 g, 82%) as a colorless oil. MS (ESI) calculated for (C15H19BF2O5) [M+H]⁺, 329.13; found, 329.10.

Step 3: methyl 5-(difluoromethoxy)-2-(3-fluoropyridin-2-yl)benzoate

[0989] To a stirred solution of methyl 5-(difluoromethoxy)-2-(4,4,5,5-tetramethyl-l,3,2- dioxaborolan-2-yl)benzoate (33.00 g, 100.57 mmol) in 1,4-dioxane (330 mL) and H₂O (33 mL) were added 2-chloro-3-fhioropyridine (13.23 g, 100.57 mmol), K2CO3 (41.70 g, 301.72 mmol) and Pd(dppf)Cl₂ (7.36 g, 10.06 mmol). The resulting mixture was stirred at 100 °C for 16 h under nitrogen atmosphere. The resulting mixture was diluted with water. The resulting mixture was extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous NazSC . The resulting mixture was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with PE / EtOAc (3/1) to afford methyl 5-(difluoromethoxy)-2-(3-fluoropyridin-2-yl)benzoate (15.25 g, 51%) as a yellow oil. MS (ESI) calculated for (C32H42N6O4S) [M+H]⁺, 298.06; found, 298.10.

Step 4: [2-(3-fluoro-6-mcthylpyridin-2-yl)-5-(trifluoromcthyl)phcnyl]mcthanol

[0990] To a stirred solution of methyl 5-(difhioromethoxy)-2-(3-fluoropyridin-2- yl)benzoate (15.25 g, 51.31 mmol) in THF (150 mL) was added LAH (3.89 g, 102.61 mmol) in portions at 0 °C. The resulting mixture was stirred at 0 °C for 1 h. The reaction was quenched by the addition of water (4 mL) and NaOH (aq, 10%) (4 mL) at 0 °C. The resulting mixture was filtered, the filter cake was washed with ethyl acetate. The resulting mixture was washed with brine to afford [5-(difhioromethoxy)-2-(3-fhioropyridin-2-yl)phenyl]methanol (15.70 g, crude) as a brown solid. MS (ESI) calculated for (C13H10F3NO2) [M+H]⁺, 270.07; found, 270.05.

Step 5: 2-methyl-8-(trifluoromethyl)-6H-isochromeno[4,3-b]pyridine

[0991] To a stirred solution of [5-(difhioromethoxy)-2-(3-fluoropyridin-2- yl)phenyl]methanol (15.70 g, 58.32 mmol) in DMF (150 mL) was added K2CO3 (40.30 g, 291.58 mmol) at room temperature. The resulting mixture was stirred at 80 °C for 16 h. The resulting mixture was diluted with water. The resulting mixture was extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous NaiSC The resulting mixture was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with PE / EtOAc (1/1) to afford 8-(difluoromethoxy)-6H- isochromeno[4,3-b]pyridine (7.58 g, 52%) as a yellow solid. MS (ESI) calculated for (C13H9F2NO2) [M+H]⁺, 250.06; found, 250.05.

Step 6: 1:1 mixture of (4aS, 10bS)-8-(difluoromethoxy )-2, 3, 4, 4a, 6, lOb-hexahydro- 1H- isochromeno[4,3-b]pyridine and (4aR, 10bR)-8-(difluoromethoxy)-2,3,4,4a,6, lOb-hexahydro- lH-isochromeno[4,3-b]pyridine formate (A24)

[0992] To a solution of 8-(difhioromethoxy)-6H-isochromeno[4,3-b]pyridine (2.00 g, 8.02 mmol) in AcOH (20 mL) was added PtO2 (200 mg) under nitrogen atmosphere. The mixture was hydrogenated at room temperature for 16 h under hydrogen atmosphere using a hydrogen balloon. The resulting mixture was filtered through a Celite pad, the filter cake was washed with ethyl acetate. The filtrate was concentrated under reduced pressure. The resulting residue was purified by reverse phase flash column chromatography with 5-20% acetonitrile in water (0.1% FA) to afford a 1:1 mixture of (4aS,10bS)-8-(difluoromethoxy)- 2,3,4,4a,6,10b-hexahydro-lH-isochromeno[4,3-b]pyridine formate and (4aR,10bR)-8- (difhioromethoxy)-2,3,4,4a,6, lOb-hexahydro- lH-isochromeno[4,3-b]pyridine formate (2.10 g, 87%) as a white solid. MS (ESI) calculated for (C13H15F2NO2) [M+H]⁺, 256.11 ; found, 256.15. ^XH NMR (400 MHz, DMSO-tfc) 8 8.32 (s, 1H), 7.60 - 7.50 (m, 1H), 7.42 - 7.05 (m, 2H), 7.04 - 6.87 (m, 1H), 4.92 - 4.88 (m, 1H), 4.79 - 4.73 (m, 1H), 3.98 - 3.96 (m, 1H), 3.79 - 3.78 (m, 1H), 3.10 - 2.98 (m, 1H), 2.92 - 2.83 (m, 1H), 2.02 - 1.96 (m, 1H), 1.86 - 1.66 (m, 2H), 1.53 - 1.42 (m, 1H).

Step 7 : (4aS, 10bS)-8-(difluoromethoxy)-2, 3, 4, 4a, 6, lOb-hexahydro- lH-isochromeno[4,3- b]pyridine, isomer 1:

A24, isomer 1 and

(4aR,10bR)-8-(difluoromethoxy)-2,3,4,4a,6,10b-hexahydro-lH-isochromeno[4,3-b]pyridine, isomer 2:

A24, isomer 2

[0993] A 1:1 mixture of (4aS,10bS)-8-(difluoromethoxy)-2,3,4,4a,6,10b-hexahydro-lH- isochromeno[4,3-b]pyridine and (4aR, 10bR)-8-(difluoromethoxy)-2,3,4,4a,6, lOb-hexahydro- lH-isochromeno[4,3-b]pyridine (1.17 g, 4.58 mmol) was purified by Prep-Chiral SFC with the following conditions (Column: CHIRAL ART Cellulose-SC, 3*25 cm, 5 pm; Mobile Phase A: CO2, Mobile Phase B: MEOH; Flow rate: 110 mL/min; Gradient: isocratic 15% B; Wave Length: 220 rnn; RTl(min): 3.8; RT2(min): 4.9; Sample Solvent: MeOH) to afford (4aS,10bS)-8-(difluoromethoxy)-2,3,4,4a,6,10b-hexahydro-lH-isochromeno[4,3-b]pyridine (530 mg), isomer 1 (A24, isomer 1) as a white solid with the first peak on chiral SFC. MS (ESI) calculated for (C13H15F2NO2) [M+H]⁺, 256.11; found, 256.20. 'H NMR (400 MHz, DMSO-d₆) 8 7.43 - 7.02 (m, 3H), 6.92 (d, J = 2.4 Hz, 1H), 4.85 (d, J= 15.6 Hz, 1H), 4.69 (d, J= 15.6 Hz, 1H), 3.69 - 3.62 (m, 2H), 2.98 - 2.89 (m, 1H), 2.78 - 2.66 (m, 1H), 2.01 - 1.92 (m, 1H), 1.84 - 1.70 (m, 1H), 1.68 - 1.52 (m, 1H), 1.45 - 1.34 (m, 1H).

[0994] The stereochemistry of A24 isomer 1 was determined by crystallography based on the co-crystal structure of a compound with PRMT5 enzyme, where the compound was prepared using A24 isomer 1.

[0995] The chiral separation also afford (4aR,10bR)-8-(difluoromethoxy)-2,3,4,4a,6,10b- hexahydro-lH-isochromeno[4,3-b]pyridine (470 mg), isomer 2 (A24, isomer 2) as a white solid with the second peak on chiral SFC. MS (ESI) calculated for (C13H15F2NO2) [M+H]⁺, 256.11; found, 256.20. 'H NMR (400 MHz, DMSO-d₆) 6 7.43 - 7.02 (m, 3H), 6.92 (d, J = 2.4 Hz, 1H), 4.85 (d, J = 15.6 Hz, 1H), 4.69 (d, J= 15.6 Hz, 1H), 3.69 - 3.62 (m, 2H), 2.98 - 2.89 (m, 1H), 2.78 - 2.66 (m, 1H), 2.01 - 1.92 (m, 1H), 1.84 - 1.70 (m, 1H), 1.68 - 1.52 (m, 1H), 1.45 - 1.34 (m, 1H)

Intermediate A25: rel-(4aS,10bS)-8-cyclopropoxy-2,3,4,4a,6,10b-hexahydro-lH- isochromeno[4,3-b]pyridine hydrochloride

[0996] To a stirred solution of methyl 2-bromo-5-chlorobenzoate (30.00 g, 120.25 mmol) and (E)-tert-butyldiphenyl((5-(4,4,5,5-tetramethyl- 1 ,3,2-dioxaborolan-2-yl)pent-4-en- 1 - yl)oxy)silane (59.59 g, 132.27 mmol) in 1,4-dioxane (300 mL) and H2O (30 mL) were added K2CO3 (33.24 g, 240.49 mmol) and Pd(dppf)C12-CH₂Cl₂ (9.82 g, 12.03 mmol) at room temperature under nitrogen atmosphere. The resulting mixture was stirred at 100 °C for 16 h. The reaction mixture was quenched by the addition of water/ice and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under vacuum. The resulting residue was purified by flash column chromatography and eluted with 0-8% ethyl acetate in petroleum ether to afford methyl (E)-2-(5-((tert-butyldiphenylsilyl)oxy)pent-l-en-l-yl)-5-chlorobenzoate (58.10 g, 97%) as a light yellow oil. MS ESI calculated for C29H33ClO3Si [M+H]⁺, 493.19; found, 493.20. ’H NMR (300 MHz, DMSO-d₆) 87.83 - 7.74 (m, 1H), 7.65 - 7.53 (m, 6H), 7.47 - 7.40 (m, 6H), 6.98 (dd, 7 = 16.0, 1.6 Hz, 1H), 6.24 (dt, J= 15.8, 6.8 Hz, 1H), 3.84 (s, 3H), 3.67 (t, J = 6.0 Hz, 2H), 2.36 - 2.15 (m, 2H), 1.76 - 1.61 (m, 2H), 1.00 (s, 9H). Absolute stereochemistry was not determined.

Step-2:

[0997] To a stirred solution of tert-butyl carbamate (23.05 g, 196.77 mmol) in propan- l-ol (490 mL) was added a solution of NaOH (6.96 g, 173.92 mmol) in H2O (436 mL) at room temperature. The resulting mixture was stirred at room temperature for 10 minutes. Then 1,3- dichloro-5,5-dimethylimidazolidine-2, 4-dione (18.76 g, 95.21 mmol) was added to the mixture at room temperature. After stirring at room temperature for 30 minutes, potassium osmate(VI) dihydrate (2.34 g, 6.35 mmol) was added to the mixture, this was followed by the addition of a solution of (DHQ)2PHAL (supplier: Shanghai Accela ChemBio Co., Ltd. CAS# 140924-50-1) (4.94 g, 6.35 mmol) in propan-l-ol (64 mL) and a solution of methyl (E)-2-(5- ((tert-butyldiphenylsilyl)oxy)pent-l-en-l-yl)-5-chlorobenzoate (31.30 g, 63.47 mmol) in propan-l-ol (60 mL) dropwise at 0°C. The resulting mixture was stirred at room temperature for 16 h. The reaction mixture was quenched by the addition of water and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under vacuum. The resulting residue was purified by flash column chromatography with a 330 g silica gel column and eluted with 0 - 15% ethyl acetate in petroleum ether to afford rel-tert-butyl ((3S,4S)-3-(3-((tert- butyldiphenylsilyl)oxy)propyl)-7-chloro-l-oxoisochroman-4-yl)carbamate (17.40 g, 46%) as a brown oil. MS ESI calculated for CssH^ClNOsSi [M+H]⁺, 594.24; found, 594.15. 'H NMR (300 MHz, DMSO-ifc) 5 7.88 (d, J = 2.4 Hz, 1H), 7.75 (dd, J = 8.0, 2.4 Hz, 1H), 7.64 - 7.62 (m, 5H), 7.50 - 7.40 (m, 7H), 4.88 (d, J = 9.4 Hz, 1H), 4.66 - 4.65 (m, 1H), 3.77 - 3.71 (m, 2H), 1.80 - 1.76 (m, 4H), 1.38 (s, 9H), 1.00 (s, 9H). Absolute stereochemistry was not determined.

[0998] To a stirred solution of rel-tert-butyl ((3S,4S)-3-(3-((tert- butyldiphenylsilyl)oxy)propyl)-7-chloro-l-oxoisochroman-4-yl)carbamate (17.40 g, 29.28 mmol) in THF (170 mL) was added NaBH4 (5.54 g, 146.41 mmol) at 0 °C, then boron trifluoride dimethyl etherate (18 mL, 146.41 mmol) was added dropwise at 0 °C under nitrogen atmosphere. The resulting mixture was stirred at room temperature for 16 h. The reaction mixture was quenched by the addition of water/ice and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under vacuum. The resulting residue was purified by flash column chromatography with a 120 g silica gel column and eluted with 0-10% ethyl acetate in petroleum ether to afford rel-tert-butyl ((3S,4S)-3-(3-((tert-butyldiphenylsilyl)oxy)propyl)-7- chloroisochroman-4-yl)carbamate (6.40 g, 37%) as a colorless oil. MS ESI calculated for C33H₄₂ClNO₄Si [M+H]⁺, 580.26; found, 580.20. 'H NMR (300 MHz, DMSO- ₆) 8 7.61 - 7.58 (m, 4H), 7.45 - 7.41 (m, 6H), 7.31 - 7.21 (m, 2H), 7.17 (d, J = 2.0 Hz, 1H), 7.02 (d, J = 9.6 Hz, 1H), 4.75 (d, J= 15.6 Hz, 1H), 4.62 - 4.50 (m, 2H), 3.73 - 3.55 (m, 3H), 1.68 - 1.60 (m, 4H), 1.38 (s, 9H), 0.99 (s, 9H). Absolute stereochemistry was not determined.

Step-4:

[0999] To a stirred solution of rel-tert-butyl ((3S,4S)-3-(3-((tert- butyldiphenylsilyl)oxy)propyl)-7-chloroisochroman-4-yl)carbamate (6.40 g, 11.03 mmol) in THF (64 mL) was added a solution of TBAF (4.33 g, 16.55 mmol) in THF (5 mL) at 0 °C. The resulting mixture was stirred at room temperature for 1 h. The reaction mixture was concentrated under vacuum. The resulting residue was purified by flash column chromatography with an 80 g silica gel column and eluted with 0-8% ethyl acetate in petroleum ether to afford rel-tert-butyl ((3S,4S)-7-chloro-3-(3-hydroxypropyl)isochroman-4- yl)carbamate (2.98 g, 79%) as a colorless oil. MS ESI calculated for C17H24CINO4 [M+H]⁺, 342.14; found, 342.05. 'H NMR (400 MHz, DMSO-d₆) 8 7.30 - 7.23 (m, 2H), 7.18 (d, J = 2.0 Hz, 1H), 6.96 (d, J = 9.6 Hz, 1H), 4.76 (d, J = 15.6 Hz, 1H), 4.64 - 4.54 (m, 2H), 4.39 (t, J= 5.2 Hz, 1H), 3.62 - 3.59 (m, 1H), 3.44 - 3.37 (m, 2H), 1.60 - 1.51 (m, 4H), 1.39 (s, 9H). Absolute stereochemistry was not determined.

Step-5:

[1000] To a stirred solution of rel-tert-butyl ((3S,4S)-7-chloro-3-(3- hydroxypropyl)isochroman-4-yl)carbamate (2.50 g, 7.31 mmol) in toluene (25 mL) was added 2-(tributyl-X⁵-phosphaneylidene)acetonitrile (CAS No. 157141-27-0) (3.53 g, 14.63 mmol) at room temperature under nitrogen atmosphere. The resulting mixture was stirred at 110 °C for 16 h. The resulting mixture was concentrated under reduced pressure. The resulting residue was purified by flash column chromatography with a 40 g silica gel column and eluted with 0-20% ethyl acetate in petroleum ether to afford rel-tert-butyl (4aS,10bS)-8- chloro-2,3,4,4a,6, 1 Ob-hexahydro- lH-isochromeno[4,3-b]pyridine- 1 -carboxylate (1.65 g, 69%) as a light yellow oil. MS ESI calculated for C17H22CINO3 [M+H]⁺, 324.13; found, 324.05. NMR (300 MHz, DMSO-d₆) 87.36 (dd, J = 8.4, 2.2 Hz, 1H), 7.23 (d, J = 2.2 Hz, 1H), 7.03 (d, J = 8.4 Hz, 1H), 5.27 (d, J = 6.0 Hz, 1H), 4.81 - 4.65 (m, 2H), 4.08 - 3.99 (m, 1H), 3.81 (d, J= 13.4 Hz, 1H), 2.31 (t, J= 12.4 Hz, 1H), 1.76 - 1.52 (m, 4H), 1.47 (s, 9H). Absolute stereochemistry was not determined.

Step-6:

[1001] To a stirred solution of rel-tert-butyl (4aS,10bS)-8-chloro-2,3,4,4a,6,10b- hexahydro-lH-isochromeno[4,3-b]pyridine-l-carboxylate (200 mg, 0.62 mmol) and K2CO3 (1135 mg, 8.22 mmol) in DMF (18 mL) and H2O (2 mL) were added Herrmann's palladacycle (50 mg, 0.05 mmol) and t-BuXPhos (92 mg, 0.22 mmol) at room temperature under nitrogen atmosphere. The resulting mixture was stirred at 120 °C for 3 h. The mixture was allowed to cool at room temperature and diluted with water. The resulting mixture was extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SC>4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0 ~ 20% EtOAc in PE to afford rel-tert-butyl (4aS,10bS)-8-hydroxy-2,3,4,4a,6,10b-hexahydro-lH-isochromeno[4,3- b]pyridine-l -carboxylate (200 mg, 42%) as a colorless oil. MS ESI calculated for C17H23NO4 [M+H]⁺, 306.16; found, 306.15. Absolute stereochemistry was not determined.

Step-7:

[1002] To a stirred solution of rel-tert-butyl (4aS,10bS)-8-hydroxy-2,3,4,4a,6,10b- hexahydro-lH-isochromeno[4,3-b]pyridine-l-carboxylate (120 mg, 0.39 mmol) and CS2CO3 (384 mg, 1.18 mmol) in DMF (5 mL) was added iodocyclopropane (99 mg, 0.59 mmol) at room temperature under nitrogen atmosphere. The resulting mixture was stirred at 120 °C for overnight. The mixture was allowed to cool at room temperature and diluted with water. The resulting mixture was extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SO4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0 ~ 25% EtOAc in PE to afford rel-tert-butyl (4aS,10bS)-8-cyclopropoxy-2,3,4,4a,6,10b- hexahydro-lH-isochromeno[4,3-b]pyridine-l-carboxylate (130 mg, 57%) as a colorless oil. MS ESI calculated for C20H27NO4 [M+H]⁺, 346.19; found, 346.20. Absolute stereochemistry was not determined.

Step-8:

A25

[1003] To a solution of rel-tert-butyl (4aS,10bS)-8-cyclopropoxy-2,3,4,4a,6,10b- hexahydro-lH-isochromeno[4,3-b]pyridine-l-carboxylate (130 mg, 0.38 mmol) in DCM (2.5 mL) was added HC1 (4M in 1,4-dioxane) (2.5 mL). The mixture was stirred at room temperature for 2 h under nitrogen atmosphere. The resulting mixture was concentrated under vacuum to afford rel-(4aS,10bS)-8-cyclopropoxy-2,3,4,4a,6,10b-hexahydro-lH- isochromeno[4,3-b]pyridine hydrochloride (A25) (75 mg, 96%) as a white solid. MS ESI calculated for C15H19NO2 [M+H]⁺, 246.14; found, 246.15. 'H NMR (400 MHz, DMSO-d₆) 8 9.70 (d, J = 11.2 Hz, 1H), 8.53 (d, J= 11.2 Hz, 1H), 7.53 (d, J = 8.4 Hz, 1H), 7.01 (dd, J = 8.4, 2.8 Hz, 1H), 6.90 (d, 7 = 2.4 Hz, 1H), 4.97 - 4.72 (m, 2H), 4.22 (d, J = 10.0 Hz, 1H), 3.94 - 3.93 (m, 1H), 3.89 - 3.81 (m, 1H), 3.19 - 2.93 (m, 2H), 2.04 - 1.92 (m, 1H), 1.92 - 1.73 (m, 2H), 1.73 - 1.59 (m, 1H), 0.86 - 0.75 (m, 2H), 0.70 - 0.58 (m, 2H). Absolute stereochemistry was not determined.

Intermediate A26 isomer 1: (4aR,9bR)-7-(trifhioromethyl)-l,2,3,4,4a,9b- hexahydrofuro[2,3-b:4,5-b']dipyridine, isomer 1:

A26, isomer 1 . _anj Intermediate A26 isomer 2: (4aS,9bS)-7-(trifhioromethyl)-l,2,3,4,4a,9b-hexahydrofuro[2,3- b:4,5-b']dipyridine, isomer 2:

A26, isomer 2

Step-1:

[1004] To a stirred mixture of 3-bromo-2-chloro-6-(trifluoromethyl)pyridine (25.00 g, 95.99 mmol), (E)-tert-butyldiphenyl((5-(4,4,5,5-tetramethyl-l,3,2-dioxaborolan-2-yl)pent-4- en-l-yl)oxy)silane (51.89 g, 115.18 mmol) and K2CO3 (39.80 g, 287.97 mmol) in 1,4- dioxane (300 mL) and H2O (30 mL) was added Pd(dppf)Ch (7.84 g, 9.59 mmol) at room temperature under nitrogen atmosphere. Then the mixture was stirred at 80 °C for 2 h under nitrogen atmosphere. The resulting mixture was quenched with water and extracted with EtOAc. The combined organic layers were washed with water, dried over anhydrous Na2SC>4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by flash column chromatography with 10-20% ethyl acetate in petroleum ether to afford (E)- 3-(5-((tert-butyldiphenylsilyl)oxy)pent- 1 -en- 1 -yl)-2-chloro-6-(trifhioromethyl)pyridine (48 g, 99%) as a yellow oil. MS ESI calculated for C₂7H29ClF₃NOSi [M+H]⁺, 504.17; found, 504.15.

Step-2: [1005] To a stirred mixture of tert-butyl carbamate (16.73 g, 142.83 mmol) in propan-l-ol (200 mL) was added a solution of NaOH (5.14 g, 128.55 mmol) in H2O (200 mL) at 0 °C and then stirred for 15 minutes. l,3-dichloro-5,5-dimethylimidazolidine-2, 4-dione (14.07 g, 71.41 mmol) was added to the mixture, the mixture was stirred at 0 °C for 30 minutes. Then (E)-3- (5-((tert-butyldiphenylsilyl)oxy)pent- 1-en- l-yl)-2-chloro-6-(trifluoromethyl)pyridine (24.00 g, 47.61 mmol), (DHQ)2PHAL (supplier: Shanghai Accela ChemBio Co., Ltd. CAS# 140924-50-1) (3.71 g, 4.76 mmol) and Potassium osmate(VI) dihydrate (1.75 g, 4.76 mmol) were added to the mixture. The mixture was stirred at room temperature for 12 h. The resulting mixture was quenched by water and extracted with ethyl acetate. The combined organic layers were washed with water, dried over anhydrous Na2SC>4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by flash column chromatography with 0-11% ethyl acetate in petroleum ether to afford a 4:1 mixture of tertbutyl ((lS,2S)-5-((tert-butyldiphenylsilyl)oxy)-l-(2-chloro-6-(trifluoromethyl)pyridin-3-yl)- 2-hydroxypentyl)carbamate and tert-butyl ((lR,2R)-5-((tert-butyldiphenylsilyl)oxy)-l-(2- chloro-6-(trifhioromethyl)pyridin-3-yl)-2-hydroxypentyl)carbamate (10.0 g, 32%) as a yellow solid. MS ESI calculated for C32H4oClF₃N204Si [M+H]⁺, 637.24; found, 637.20.

Step-3:

[1006] To a stirred mixture of a 4:1 mixture of tert-butyl ((lS,2S)-5-((tert- butyldiphenylsilyl)oxy)-l-(2-chloro-6-(trifluoromethyl)pyridin-3-yl)-2- hydroxypentyl)carbamate and tert-butyl ((lR,2R)-5-((tert-butyldiphenylsilyl)oxy)-l-(2- chloro-6-(trifluoromethyl)pyridin-3-yl)-2-hydroxypentyl)carbamate (9.90 g, 15.53 mmol) and CS2CO3 (15.19 g, 46.60 mmol) in toluene (100 mL) were added JohnPhos (0.93 g, 3.10 mmol) and Pd(OAc)2 (0.35 g, 1.55 mmol) at room temperature under nitrogen atmosphere. The resulting mixture was stirred at 100 °C for 2 h. The precipitated solids were filtered, the filter cake was washed with DCM. The filtrate was concentrated under vacuum. The residue was purified by flash column chromatography with 10-20% ethyl acetate in petroleum ether to afford a 4:1 mixture of tert-butyl ((2S,3S)-2-(3-((tert-butyldiphenylsilyl)oxy)propyl)-6- (trifhioromethyl)-2,3-dihydrofuro[2,3-b]pyridin-3-yl)carbamate and tert-butyl ((2R,3R)-2-(3- ((tert-butyldiphenylsilyl)oxy)propyl)-6-(trifluoromethyl)-2,3-dihydrofuro[2,3-b]pyridin-3- yl)carbamate (3.90 g, 41%) as a yellow solid. MS ESI calculated for CsiHsgFsNiC Si [M+H]⁺, 601.26; found, 601.24.

Step-4:

[1007] To a 4: 1 mixture of tert-butyl ((2S,3S)-2-(3-((tert-butyldiphenylsilyl)oxy)propyl)-6- (trifluoromethyl)-2,3-dihydrofuro[2,3-b]pyridin-3-yl)carbamate and tert-butyl ((2R,3R)-2-(3- ((tert-butyldiphenylsilyl)oxy)propyl)-6-(trifluoromethyl)-2,3-dihydrofuro[2,3-b]pyridin-3- yl)carbamate (3.90 g, 6.49 mmol) in THF (40 mL) was added TBAF (3.39 g, 12.98 mmol). The mixture was stirred at room temperature for 16 h. The mixture was diluted with DCM and then washed with brine. The organic layer was dried over anhydrous Na2SC>4, filtered, and concentrated under vacuum. The residue was purified by flash column chromatography with 30-50% ethyl acetate in petroleum ether to afford a 4: 1 mixture of tert-butyl ((2S,3S)-2- (3-hydroxypropyl)-6-(trifhioromethyl)-2,3-dihydrofuro[2,3-b]pyridin-3-yl)carbamate and tert-butyl ((2R,3R)-2-(3-hydroxypropyl)-6-(trifluoromethyl)-2,3-dihydrofuro[2,3-b]pyridin-3- yl)carbamate (1.90 g, 80%) as a yellow solid. MS ESI calculated for C16H21F3N2O4 [M+H]⁺, 363.15; found, 363. 18.

[1008] To a stirred a 4: 1 mixture of tert-butyl ((2S,3S)-2-(3-hydroxypropyl)-6- (trifhioromethyl)-2,3-dihydrofuro[2,3-b]pyridin-3-yl)carbamate and tert-butyl ((2R,3R)-2-(3- hydroxypropyl)-6-(trifhioromethyl)-2,3-dihydrofuro[2,3-b]pyridin-3-yl)carbamate ( 1.90 g, 5.24 mmol) in toluene (20 mL) was added 2-(tributyl-X⁵-phosphaneylidene)acetonitrile (CAS No. 157141-27-0) (3.80 g, 15.73 mmol) at room temperature, and then the mixture was stirred at 110 °C for 1 h. The resulting mixture was concentrated under reduced pressure. The residue was purified by flash column chromatography with 10-20% ethyl acetate in petroleum ether to afford a 4: 1 mixture of tert-butyl (4aS,9bS)-7-(trifluoromethyl)-3,4,4a,9b- tetrahydrofuro[2,3-b:4,5-b']dipyridine-l(2H)-carboxylate and tert-butyl (4aR,9bR)-7- (trifluoromethyl)-3,4,4a,9b-tetrahydrofuro[2,3-b:4,5-b^,]dipyridine-l(2H)-carboxylate (1.40 g, 77%) as a light yellow solid. MS ESI calculated for C16H19F3N2O3 [M+H]⁺, 345.13; found, 345.15.

Step-6:

[1009] A mixture of 4:1 mixture of tert-butyl (4aS,9bS)-7-(trifluoromethyl)-3,4,4a,9b- tetrahydrofuro[2,3-b:4,5-b']dipyridine-l(2H)-carboxylate and tert-butyl (4aR,9bR)-7- (trifhioromethyl)-3,4,4a,9b-tetrahydrofuro[2,3-b:4,5-b']dipyridine-l(2H)-carboxylate (1.40 g, 4.06 mmol) and HC1 (4M in 1,4-dioxane) (20 mL) was stirred at room temperature for 1 h. The resulting mixture was concentrated under reduced pressure to afford a 4:1 mixture of (4aS,9bS)-7-(trifluoromethyl)-l,2,3,4,4a,9b-hexahydrofuro[2,3-b:4,5-b']dipyridine and (4aR,9bR)-7-(trifhioromethyl)-l,2,3,4,4a,9b-hexahydrofuro[2,3-b:4,5-b']dipyridine hydrochloride (1.8 g, crude) as a yellow solid. MS ESI calculated for C11H11F3N2O [M+H]⁺, 245.08; found, 245.00.

Step-7:

A26 isomer 2

[1010] A 4:1 mixture of (4aS,9bS)-7-(trifhioromethyl)-l,2,3,4,4a,9b-hexahydrofuro[2,3- b:4,5-b']dipyridine isomer 2 and (4aR,9bR)-7-(trifluoromethyl)-l,2,3,4,4a,9b- hexahydrofuro[2,3-b:4,5-b']dipyridine hydrochloride isomer 1 (1.80 g, 7.37 mmol) was purified by Prep-SFC with the following conditions (Column: CHIRALPAK PAK AD-H, 30*250mm; Mobile Phase B: ETOH (0.1% 2M NH3-MEOH); How rate: 100 mL/min; Gradient: isocratic 20% B; RTl(min): 2.6; RT2(min): 4; Sample Solvent: MEOH; Injection Volume: 2 mL; Number Of Runs: 20) to afford (4aR,9bR)-7-(trifluoromethyl)-l,2,3,4,4a,9b- hexahydrofuro[2,3-b:4,5-b']dipyridine, isomer 1 (A26 isomer 1) (170 mg) as a white solid with shorter retention time. MS ESI calculated for C11H11F3N2O [M+H]⁺, 245.08; found, 245.00. 'H NMR (400 MHz, DMSO- ₆) 8 8.01 (d, J= 8.0 Hz, 1H), 7.47 (d, J= 8.0 Hz, 1H), 4.81 - 4.72 (m, 2H), 3.00 - 2.80 (m, 2H), 2.19 - 1.92 (m, 2H), 1.16 - 1.47 (m, 2H).

[1011] The chiral resolution also afforded (4aS,9bS)-7-(trifluoromethyl)-l,2,3,4,4a,9b- hexahydrofuro[2,3-b:4,5-b']dipyridine, isomer 2 (A26, isomer 2) (500 mg) as a white solid with longer retention time. MS ESI calculated for C11H11F3N2O [M+H]⁺, 245.08; found, 245.00. 'H NMR (400 MHz, DMSO- ₆) 8 8.01 (d, J= 8.0 Hz, 1H), 7.47 (d, J= 8.0 Hz, 1H), 4.81 - 4.72 (m, 2H), 3.00 - 2.80 (m, 2H), 2.19 - 1.92 (m, 2H), 1.16 - 1.47 (m, 2H). Absolute stereochemistry was determined by single crystal X-ray crystallography of Example 38 prepared using A26 isomer 2. Intermediate A27: 1:1 mixture of rel-(4aR,9bR)-l,2,3,4,4a,9b-hexahydrobenzofuro[3,2- b]pyridine-7-carbonitrile isomer 1 and rel-(4aR,9bR)-l,2,3,4,4a,9b-hexahydrobenzofuro[3,2- b]pyridine-7-carbonitrile hydrochloride isomer 2

Step-1:

[1012] To a stirred mixture of (4-chloro-2-hydroxyphenyl)boronic acid (10.00 g, 58.01 mmol) and 2-bromo-3-fluoropyridine (10.21 g, 58.01 mmol) in 1,4-dioxane (100 mL) and H2O (10 mL) were added Pd(dppf)Cl₂ (4.24 g, 5.80 mmol) and K2CO3 (24.05 g, 174.04 mmol) at room temperature under nitrogen atmosphere. The resulting mixture was stirred at 90°C for 2 h under nitrogen atmosphere. The mixture was concentrated under vacuum. The residue was diluted by water and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered and concentrated under vacuum. The residue was purified by flash column chromatography with 0-60% ethyl acetate in petroleum ether to afford 5-chloro-2-(3-fluoropyridin-2-yl)phenol (10.70 g, 82%) as a yellow solid. MS ESI calculated for C11H7CIFNO [M+l]⁺, 224.03; found, 224.10.

Step-2:

[1013] A mixture of 5-chloro-2-(3-fluoropyridin-2-yl)phenol (10.70 g, 47.84 mmol) and K2CO3 (19.84 g, 143.51 mmol) in DMF (100 mL) was stirred at 120 °C for 3 h. The precipitated solids were filtered off by filtration and washed with EtOAc. The filtrate was diluted with water and extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SC>4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with PE/ EtOAc (1:1) to afford 7-chlorobenzofuro[3,2-b]pyridine (8.00 g, 82%) as a white solid. MS ESI calculated for CHH₆C1NO [M+H]⁺, 204.01; found, 204.05.

Step-3:

[1014] To a stirred mixture of 7-chlorobenzofuro[3,2-b]pyridine (9.10 g, 44.68 mmol) and B(CeFs)3 (2.29 g, 4.46 mmol) in toluene (90 mL) were added HBpin (28.60 g, 223.44 mmol) and Ph2NH (30.25 g, 178.75 mmol) at room temperature under nitrogen atmosphere. The resulting mixture was stirred at 110 °C for 16 h. The resulting mixture was concentrated under reduced pressure. The residue was purified by silica gel column chromatography and eluted with CFhCh/MeOH (5:1) to afford a 1:1 mixture of rel-(4aS,9bS)-7-chloro- l,2,3,4,4a,9b-hexahydrobenzofuro[3,2-b]pyridine isomer 1 and rel-(4aR,9bR)-7-chloro- l,2,3,4,4a,9b-hexahydrobenzofuro[3,2-b]pyridine isomer 2 (6.90 g, 73%) as a yellow solid. MS ESI calculated for C11H12CINO [M+H]⁺, 210.06; found, 210.15. The relative stereochemistry is arbitrarily assigned.

Step-4:

[1015] To a stirred 1:1 mixture of rel-(4aS,9bS)-7-chloro-l,2,3,4,4a,9b- hexahydrobenzofuro[3,2-b]pyridine isomer 1 and rel-(4aR,9bR)-7-chloro-l,2,3,4,4a,9b- hexahydrobenzofuro[3,2-b]pyridine isomer 2 (4.70 g, 22.41 mmol) and BOC2O (4.89 g, 22.41 mmol) in methanol (47 mL) was added TEA (6.81 g, 67.24 mmol) dropwise at room temperature. The resulting mixture was stirred at room temperature for 4 h. The resulting mixture was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with CH2CI2 / MeOH (5:1) to afford a 1:1 mixture of rel-tert- butyl (4aS ,9bS)-7 -chloro-3 ,4,4a,9b-tetrahydrobenzofuro [3 ,2-b]pyridine- 1 (2H)-carboxylate isomer 1 and rel-tert-butyl (4aR, 9bR)-7-chloro-3, 4,4a, 9b-tetrahydrobenzofuro [3,2- b]pyridine-l(2H)-carboxylate isomer 2 (6.00 g, 86%) as a white solid. MS ESI calculated for C16H20CINO3 [M+l]⁺, 310.11; found, 310.20. The relative stereochemistry is arbitrarily assigned.

Step-5:

[1016] To a stirred 1:1 mixture of rel-tert-butyl (4aS,9bS)-7-chloro-3,4,4a,9b- tetrahydrobenzofuro[3,2-b]pyridine-l(2H)-carboxylate isomer 1 and rel-tert-butyl (4aR,9bR)- 7-chloro-3,4,4a,9b-tetrahydrobenzofuro[3,2-b]pyridine-l(2H)-carboxylate isomer 2 (3.00 g, 9.68 mmol) in DMF (30 mL) were added Zn(CN)₂ (3.41 g, 29.05 mmol), XPhos (0.46 g, 0.96 mmol) and Zinc powder (2.53 g, 38.73 mmol). The resulting mixture was stirred at 130 °C for 2 h under nitrogen atmosphere. The mixture was filtered. The filtrate was purified directly by reverse phase flash column chromatography, eluted with 10 - 70 % acetonitrile in water to afford a 1:1 mixture of rel-tert-butyl (4aS,9bS)-7-cyano-3,4,4a,9b-tetrahydrobenzofuro[3,2- b]pyridine-l(2H)-carboxylate isomer 1 and rel-tert-butyl (4aR,9bR)-7-cyano-3,4,4a,9b- tetrahydrobenzofuro[3,2-b]pyridine-l(2H)-carboxylate isomer 2 (2.00 g, 68%) as a white solid. MS ESI calculated for C17H20N2O3 [M+H]⁺, 301.15; found, 301.20. The relative stereochemistry is arbitrarily assigned.

Step-6:

[1017] A mixture of 1:1 mixture of rel-tert-butyl (4aS,9bS)-7-cyano-3,4,4a,9b- tetrahydrobenzofuro[3,2-b]pyridine-l(2H)-carboxylate isomer 1 and rel-tert-butyl (4aR,9bR)- 7-cyano-3,4,4a,9b-tetrahydrobenzofuro[3,2-b]pyridine-l(2H)-carboxylate isomer 2 (2.00 g, 6.65 mmol) and HC1 (4M in 1,4-dioxane) (20 mL) was stirred at room temperature for 1 h. The resulting mixture was concentrated under reduced pressure. The residue was purified by reverse phase flash column chromatography, eluted with 10-80 % acetonitrile in water to afford a 1:1 mixture of rel-(4aR,9bR)-l,2,3,4,4a,9b-hexahydrobenzofuro[3,2-b]pyridine-7- carbonitrile isomer 1 and rel-(4aR,9bR)-l,2,3,4,4a,9b-hexahydrobenzofuro[3,2-b]pyridine-7- carbonitrile hydrochloride isomer 2 (A27) (1.00 g, 75%) as a white solid. MS ESI calculated for C12H12N2O [M+l]⁺, 201.09; found, 201.20. 'H NMR (400 MHz, DMSO-J₆) 8 10.74 (br, 1H), 8.75 (br, 1H), 7.81 (d, J = 7.6 Hz, 1H), 7.56 (d, J = 1.2 Hz, 1H), 7.52 (dd, J = 8.0, 1.2 Hz, 1H), 4.90 - 4.80 (m, 2H), 3.11 - 3.07 (m, 1H), 2.94 - 2.88 (m, 1H), 2.24 - 2.18 (m, 1H), 2.12 - 2.00 (m, 1H), 1.77 - 1.70 (m, 2H). The relative stereochemistry is arbitrarily assigned.

Step-7:

A27, isomer 1 _an( A27, isomer 2

[1018] A 1:1 mixture of rel-(4aS,9bS)-l,2,3,4,4a,9b-hexahydrobenzofuro[3,2-b]pyridine-7- carbonitrile isomer 1 and rel-(4aR,9bR)-l,2,3,4,4a,9b-hexahydrobenzofuro[3,2-b]pyridine-7- carbonitrile hydrochloride isomer 2 (1.5 g) was separated by prep-chiral SFC with the following conditions: [Column: NB_CHIRALPAK AD, 3*25 cm, 5 pm; Mobile Phase A: CO2, Mobile Phase B: MEOH; Flow rate: 100 mL/min; Gradient: isocratic 30% B; Wave Length: 220 nm; RTl(min): 3.34; RT2(min): 4.23; Sample Solvent: MEOH; Injection Volume: 1.5 mL] to afford rel-(4aR,9bR)-l,2,3,4,4a,9b-hexahydrobenzofuro[3,2-b]pyridine- 7-carbonitrile, isomer 2 (A27, isomer 2) (570 mg, 40%) as a white solid with shorter retention time. The relative and absolute stereochemistry is arbitrarily assigned.

[1019] The chiral resolution also afford rel-(4aR,9bR)-l,2,3,4,4a,9b- hexahydrobenzofuro[3,2-b]pyridine-7-carbonitrile, isomer 1 (A27, isomer 1) (630 mg, 44%) as a white solid with longer retention time. The relative and absolute stereochemistry is arbitrarily assigned.

[1020] rel-(4aR,9bR)- 1 ,2,3,4,4a,9b-hexahydrobenzofuro[3,2-b]pyridine-7-carbonitrile, isomer 2: MS ESI calculated for C12H12N2O [M+l]⁺, 201.09; found, 201.20. NMR (400 MHz, DMSO-<fe) 8 7.46 (d, 7= 7.6 Hz, 1H), 7.34 (dd, J = 7.6, 1.6 Hz, 1H), 7.29 (d, 7 = 1.2 Hz, 1H), 4.56 - 4.52 (m, 1H), 4.30 (d, 7 = 6.4 Hz, 1H), 2.59 - 2.55 (m, 2H), 1.94 -1.90 (m, 2H), 1.46 -1.40 (m, 2H).

[1021] rel-(4aR,9bR)- 1 ,2,3,4,4a,9b-hexahydrobenzofuro[3,2-b]pyridine-7-carbonitrile, isomer 1: MS ESI calculated for C12H12N2O [M+l]⁺, 201.09; found, 201.20. 'H NMR (400 MHz, DMSO-de) 8 7.46 (d, 7 = 7.6 Hz, 1H), 7.34 (dd, J = 7.6, 1.6 Hz, 1H), 7.29 (d, 7 = 1.2 Hz, 1H), 4.56 - 4.52 (m, 1H), 4.30 (d, 7 = 6.4 Hz, 1H), 2.59 - 2.55 (m, 2H), 1.94 -1.90 (m, 2H), 1.46 -1.40 (m, 2H).

Intermediate A28: rel-(4aS, 10bS)-8-isopropoxy-2,3,4,4a,6, 1 Ob-hexahydro- 1H- isochromeno[4,3-b]pyridine hydrochloride

A28

Step-1:

[1022] To a stirred solution of rel-tert-butyl (4aS,10bS)-8-hydroxy-2,3,4,4a,6,10b- hexahydro-lH-isochromeno[4,3-b]pyridine-l-carboxylate (200 mg, 0.65 mmol) and 2- iodopropane (167 mg, 0.98 mmol) in DMF (5 mL) were added K2CO3 (271 mg, 1.96 mmol) at room temperature under nitrogen atmosphere. The resulting mixture was stirred at 100 °C for 3 h. The mixture was allowed to cool at room temperature and diluted with water. The resulting mixture was extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SC>4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0 ~ 20% EtOAc in PE to afford rel-tert-butyl (4aS,10bS)-8-isopropoxy-2,3,4,4a,6,10b- hexahydro-lH-isochromeno[4,3-b]pyridine-l-carboxylate (105 mg, 46%) as a colorless oil. MS ESI calculated for C20H29NO4 [M+H]⁺, 348.21; found, 348.15. Absolute stereochemistry was not determined.

Step-2:

A28

[1023] To a stirred mixture of rel-tert-butyl (4aS,10bS)-8-isopropoxy-2,3,4,4a,6,10b- hexahydro-lH-isochromeno[4,3-b]pyridine-l-carboxylate (140 mg, 0.40 mmol) in DCM (1 mL) was added HC1 (4M in 1,4-dioxane) (1 mL) at room temperature. The resulting mixture was stirred at room temperature for 2 h. The resulting mixture was concentrated under reduced pressure to afford rel-(4aS,10bS)-8-isopropoxy-2,3,4,4a,6,10b-hexahydro-lH- isochromeno[4,3-b]pyridine hydrochloride (A28) (104 mg, 94%) as a white solid. MS ESI calculated for C15H21NO2 [M+H]⁺, 248.16; found, 248.15. 'H NMR (400 MHz, DMSO-d₆) 8 9.57 (d, 7 = 11.2 Hz, 1H), 8.51 (d, 7= 11.2 Hz, 1H), 7.47 (d, 7= 8.4 Hz, 1H), 6.89 (dd, 7 = 8.4, 2.4 Hz, 1H), 6.75 (d, J= 2.4 Hz, 1H), 4.95 - 4.75 (m, 2H), 4.71 - 4.58 (m, 1H), 4.20 (d, J= 10.0 Hz, 1H), 3.93 - 3.92 (m, 1H), 3.19 - 2.92 (m, 2H), 2.05 - 1.93 (m, 1H), 1.91 - 1.74 (m, 2H), 1.72 - 1.58 (m, 1H), 1.26 (d, J = 6.0 Hz, 6H). Absolute stereochemistry was not determined.

Intermediate A29: (4aS, 10bS)-8-(trifhioromethyl)-2,3,4,4a,6, lOb-hexahydro- 1H- pyrano[3,2-b:5,4-b']dipyridine hydrochloride

A29

[1024] To a stirred solution of methyl 3-bromo-6-chloropicolinate (10.00 g, 39.92 mmol) and Nal (17.95 g, 119.76 mmol) in MeCN (100 mL) was added TMSC1 (5.20 g, 47.90 mmol) at room temperature under nitrogen atmosphere. The resulting mixture was stirred at 80 °C for 16 h. The resulting mixture was quenched with water and extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous NaiSCh. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by Combi Flash (Biotage Isolera Prime) with a 120 g silica gel column and eluted with 0-20% ethyl acetate in petroleum ether to afford methyl 3-bromo-6-iodopicolinate (6.1 g, 44% yield) as a white solid. MS ESI calculated for C₇H₅BrINO2 [M+H]⁺, 341.85, 343.85; found, 341.80, 343.80.

Step-2:

[1025] To a stirred solution of methyl methyl 3-bromo-6-iodopicolinate (6.00 g, 17.54 mmol) and Cui (5.35 g, 28.07 mmol) in NMP (60 mL) were added KF (1.53 g, 26.32 mmol) and trimethyl(trifluoromethyl)silane (3.74 g, 26.32 mmol) at room temperature under nitrogen atmosphere. The resulting mixture was stirred at 50 °C for 16 h. The reaction mixture was quenched with water and extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SO4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by Combi Flash (Biotage Isolera Prime) with a 120 g silica gel column and eluted with 0-15% ethyl acetate in petroleum ether to afford methyl 3-bromo-6-(trifluoromethyl)picolinate (2.1 g, 42% yield) as a light-yellow oil. MS ESI calculated for CsHsBrFsbKh [M+H]⁺, 283.95, 285.95; found, 283.95, 285.95.

Step-3:

[1026] To a stirred solution of methyl 3-bromo-6-(trifluoromethyl)picolinate (20.00 g, 70.41 mmol) and (E)-tert-butyldiphenyl((5-(4,4,5,5-tetramethyl-l,3,2-dioxaborolan-2- yl)pent-4-en-l-yl)oxy)silane (31.72 g, 70.41 mmol) in 1,4-dioxane (80 mL) and H2O (8 mL) were added K2CO3 (29.19 g, 211.24 mmol) and Pd(dppf)C12-CH₂Cl₂ (5.75 g, 7.04 mmol) at room temperature under nitrogen atmosphere. The resulting mixture was stirred at 100 °C for 2 h. The reaction mixture was quenched with water and extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SC>4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by Combi Flash (Biotage Isolera Prime) with a 330 g silica gel column and eluted with 0-15% ethyl acetate in petroleum ether to afford methyl (E)-3-(5-((tert-butyldiphenylsilyl)oxy)pent-l-en-l-yl)-6- (trifhioromethyl)picolinate (31 g, 83% yield) as a yellow oil. MS ESI calculated for C29H32F₃NO₃Si [M+H]⁺, 528.21; found, 528.25.

Step-4:

[1027] To a stirred solution of tert-butyl carbamate (30.28 g, 258.50 mmol) in propan-l-ol (323 mL) and a solution of NaOH (9.01 g, 225.14 mmol) in H2O (282 mL), then 1,3- dichloro-5,5-dimethylimidazolidine-2, 4-dione (32.86 g, 166.77 mmol) was added at room temperature. After stirring at room temperature for 20 minutes, a solution of (DHQ)2PHAL (supplier: Shanghai Accela ChemBio Co., Ltd. CAS# 140924-50-1) (6.50 g, 8.33 mmol) in propan-l-ol (83 mL), a solution of methyl (E)-3-(5-((tert-butyldiphenylsilyl)oxy)pent-l-en-l- yl)-6-(trifhioromethyl)picolinate (44.00 g, 83.38 mmol) in propan-l-ol (44 mL) and Potassium osmate(VI) dihydrate (3.07 g, 8.33 mmol) were added to the mixture at 0 °C. The resulting mixture was stirred for 16 h at room temperature. The reaction mixture was quenched with water and extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SC>4. After filtration, the filtrate was concentrated under reduced pressure. The residue was dissolved in DCM (300 mL), then DCC (11.05 g, 53.57 mmol) and DMAP (0.60 g, 4.87 mmol) were added to the mixture at room temperature. The resulting mixture was stirred for 16 h at room temperature. The resulting mixture was concentrated under reduced pressure. The residue was purified by Combi Flash (Biotage Isolera Prime) with a 330 g silica gel column and eluted with 0-20% ethyl acetate in petroleum ether to afford tert-butyl N-[(5S,6S)-6-{3-[(tert-butyldiphenylsilyl)oxy]propyl}-8- oxo-2-(trifluoromethyl)-5H,6H-pyrano[3,4-b]pyridin-5-yl]carbamate (28 g, 53% yield) as a brown oil. MS ESI calculated for C₃₃H₃9F₃N2OsSi [M+H]⁺, 629.26; found, 629.30.

Step-5:

[1028] To a stirred solution of tert-butyl ((5S,6S)-6-(3-((tert- butyldiphenylsilyl)oxy)propyl)-8-oxo-2-(trifluoromethyl)-5,8-dihydro-6H-pyrano[3,4- b]pyridin-5-yl)carbamate (30.00 g, 47.71 mmol) in methanol (300 mL) was added NaBFL (3.25 g, 85.88 mmol) in portions at 0 °C under nitrogen atmosphere. The resulting mixture was stirred at room temperature for 16 h. The reaction was quenched with ice water and then extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SO4. After filtration, the filtrate was concentrated under reduced pressure. The resulting residue was purified by Combi Flash (Biotage Isolera Prime) with a 330 g silica gel column and eluted with 0-30% ethyl acetate in petroleum ether to afford tert-butyl ((1S,2S)- 5-((tert-butyldiphenylsilyl)oxy)-2-hydroxy-l-(2-(hydroxymethyl)-6-(trifluoromethyl)pyridin- 3-yl)pentyl)carbamate (14.4 g, 47% yield) as a yellow oil. MS ESI calculated for C₃₃H4₃F₃N₂O₅Si [M+H]⁺, 633.29; found, 633.25.

Step-6:

[1029] To a stirred solution of tert-butyl ((lS,2S)-5-((tert-butyldiphenylsilyl)oxy)-2- hydroxy-l-(2-(hydroxymethyl)-6-(trifluoromethyl)pyridin-3-yl)pentyl)carbamate (14.40 g, 22.75 mmol) in toluene (144 mL) was added 2-(tributyl-X⁵-phosphaneylidene)acetonitrile (CAS No. 157141-27-0) (10.98 g, 45.51 mmol) at room temperature under nitrogen atmosphere. The resulting mixture was stirred at 110 °C for 16 h under nitrogen atmosphere. The mixture was concentrated under reduced pressure. The residue was purified by Combi Flash (Biotage Isolera Prime) with a 120 g silica gel column and eluted with 0-15% ethyl acetate in petroleum ether to afford tert-butyl ((5S,6S)-6-(3-((tert- butyldiphenylsilyl)oxy)propyl)-2-(trifluoromethyl)-5,8-dihydro-6H-pyrano[3,4-b]pyridin-5- yl)carbamate (4.5 g, 32% yield) as a brown oil. MS ESI calculated for C33H41F3N2O4S1 [M+H]⁺, 615.28; found, 615.25.

Step-7:

[1030] To a stirred solution of tert-butyl ((5S,6S)-6-(3-((tert- butyldiphenylsilyl)oxy)propyl)-2-(trifluoromethyl)-5,8-dihydro-6H-pyrano[3,4-b]pyridin-5- yl)carbamate (4.50 g, 7.32 mmol) in THF (45 mL) was added TBAF (2.30 g, 8.78 mmol) at room temperature. The resulting mixture was stirred at room temperature for 1 h. The mixture was concentrated under vacuum. The residue was purified by Combi Flash (Biotage Isolera Prime) with a 120 g silica gel column and eluted with 0-60% ethyl acetate in petroleum ether to afford tert-butyl ((5S,6S)-6-(3-hydroxypropyl)-2-(trifluoromethyl)-5,8-dihydro-6H- pyrano[3,4-b]pyridin-5-yl)carbamate (1.70 g, 61% yield) as a brown oil. MS ESI calculated for C17H23F3N2O4 [M+H]⁺, 377.16; found, 377.10.

Step-8:

[1031] To a stirred solution of tert-butyl ((5S,6S)-6-(3-hydroxypropyl)-2-(trifluoromethyl)- 5,8-dihydro-6H-pyrano[3,4-b]pyridin-5-yl)carbamate (1.70 g, 4.51 mmol) in toluene (17 mL) was added 2-(tributyl- ⁵-phosphancylidcnc)acctonitrilc (CAS No. 157141-27-0) (2.18 g, 9.03 mmol) at room temperature under nitrogen atmosphere. The resulting mixture was stirred at 110 °C for 3 h under nitrogen atmosphere. 75% desired product could be detected by LCMS. The resulting mixture was concentrated under reduced pressure. The resulting residue was purified by Combi Flash (Biotage Isolera Prime) which applied to 80 g silica gel column and eluted with 0-30% ethyl acetate in petroleum ether within 25 min to afford rel-tert-butyl (4aS,10bS)-8-(trifluoromethyl)-2,3,4,4a,6,10b-hexahydro-lH-pyrano[3,2-b:5,4-b']dipyridine- 1-carboxylate (1.1 g, 85% e.e.) as a white solid, which was purified by Prep-Chiral-SFC with the following conditions [Column: CHIRALPAK IG, 3*25 cm, 5 pm; Mobile Phase A: CO2, Mobile Phase B: IPA (0.1% 7M NH3-MeOH); Flow rate: 80 mL/min; Gradient (B%): isocratic 10% B; RTl(min): 4.8; RT2(min): 6; Sample Solvent: MEOH] to afford tert-butyl (4aS,10bS)-8-(trifhioromethyl)-2,3,4,4a,6,10b-hexahydro-lH-pyrano[3,2-b:5,4-b']dipyridine- 1 -carboxylate (940 mg, 99%) as a white solid with longer retention time. MS ESI calculated for C17H21F3N2O3 [M+H]⁺, 359.15; found, 359.10.

Step-9:

[1032] A mixture of tert-butyl (4aS,10bS)-8-(trifluoromethyl)-2,3,4,4a,6,10b-hexahydro- lH-pyrano[3,2-b:5,4-b']dipyridine-l-carboxylate (1.70 g, 4.74 mmol) and hydrogen chloride (4.0 M in ethyl acetate) (17 mL) was stirred at room temperature for 16 h. The mixture was concentrated under reduced pressure to afford (4aS,10bS)-8-(trifluoromethyl)-2,3,4,4a,6,10b- hexahydro-lH-pyrano[3,2-b:5,4-b']dipyridine hydrochloride (A29) (1.1 g, 78% yield) as a white solid. MS ESI calculated for C12H13F3N2O [M+H]⁺, 259.10; found, 259.10. ’H NMR (400 MHz, DMSO-de) 6 10.40 (br, 1H), 8.93 (br, 1H), 8.41 (d, J = 8.0 Hz, 1H), 7.97 (d, J = 8.0 Hz, 1H), 5.09 - 4.80 (m, 2H), 4.55 - 4.54 (m, 1H), 4.14 (s, 1H), 3.25 - 3.24 (m, 1H), 3.07

- 3.06 (m, 1H), 2.14 - 1.58 (m, 4H). Absolute stereochemistry of A29 was determined by single crystal X-ray crystallography of Example 33, prepared using A29.

Intermediate A30: (3R,4aR*,10bR*)-8-(difluoromethoxy)-3-methoxy-2,3,4,4a,6,10b- hexahydro-lH-isochromeno[4,3-b]pyridine

A30

Step-1:

[1033] To a stirred solution of trimethylsilylacetylene (7.80 g, 79.64 mmol) in THF (400 mL) were added n-Butyllithium (2.5 M in n-hexane) (32.00 mL, 80.00 mmol) dropwise at -78 °C under nitrogen atmosphere. The resulting mixture was stirred at -78 °C for 20 minutes. Then boron trifluoride diethyl etherate (11.3 g, 79.64 mmol) was added dropwise at -78 °C. After stirring at -78 °C for additional 40 minutes, a solution of (R)-tert-butyldimethyl(oxiran- 2-ylmethoxy)silane (supplier: Shanghai Haohong Pharmaceutical Co., Ltd. CAS#124150-87- 4) (5.00 g, 26.54 mmol) in THF (100 mL) was added dropwise to above mixture at -78 °C. The resulting mixture was allowed to warm at room temperature with stirring for overnight. The reaction was quenched by the addition of NaHCCL (sat.) at room temperature. The resulting mixture was extracted with EtOAc. The combined organic layers were dried over anhydrous Na2SC>4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-70% ethyl acetate in petroleum ether to afford (R)-l-((tert-butyldimethylsilyl)oxy)-5-(trimethylsilyl)pent-4-yn-2- ol (7.6 g, 65%) as a yellow oil. MS ESI calculated for Ci4H₃o02Si2 [M+H]⁺, 287.18. found, 287.15. 'H NMR (400 MHz, DMSO-d₆) 5 4.87 (d, J= 4.8 Hz, 1H), 3.62 - 3.57 (m, 1H), 3.56 - 3.50 (m, 2H), 2.43 - 2.20 (m, 2H), 0.88 (s, 9H), 0.11 (s, 9H), 0.05 (s, 6H).

Step-2:

[1034] To a mixture of (R)-l -((tert-butyldimethylsilyl)oxy)-5-(trimethylsilyl)pent-4-yn-2- ol (7.00 g, 24.42 mmol) and N\N N⁸,N⁸-tetramethylnaphthalene-1,8-di amine (10.5 g, 48.85 mmol) DCM (70 mL) was added Trimethyloxonium tetrafluoroborate (7.20 g, 48.85 mmol) at room temperature. The resulting mixture was stirred at room temperature for 16 h. The resulting mixture was concentrated under vacuum. The residue was purified by silica gel column chromatography, eluted with 0-40% ethyl acetate in petroleum ether to afford (R)- tert-butyl((2-methoxy-5-(trimethylsilyl)pent-4-yn-l-yl)oxy)dimethylsilane (5.20 g, 70%) as a yellow oil. MS ESI calculated for Ci5H₃2O₂Si2 [M+H]⁺, 301.19. found, 301.10. 'H NMR (400 MHz, DMSO-rfe) 5 3.73 - 3.60 (m, 2H), 3.33 - 3.27 (m, 4H), 2.42 (d, J = 6.0 Hz, 2H), 0.88 (s, 9H), 0.11 (s, 9H), 0.05 (s, 6H).

Step-3:

[1035] To a solution of (R)-tert-butyl((2-methoxy-5-(trimethylsilyl)pent-4-yn-l- yl)oxy)dimethylsilane (8.50 g, 28.27 mmol) in methanol (85 mL) was added K2CO3 (7.80 g, 56.55 mmol) at room temperature. The resulting mixture was stirred at room temperature for 16 h. The resulting mixture was concentrated under vacuum. The residue was purified by silica gel column chromatography, eluted with 0-20% ethyl acetate in petroleum ether to afford (R)-tert-butyl((2-methoxypent-4-yn-l-yl)oxy)dimethylsilane (2.80 g, 43%) as a yellow oil. MS ESI calculated for C ^ChSi [M+H]⁺, 229.15. found, 229.10. 'H NMR (400 MHz, DMSO-de) 8 3.69 - 3.59 (m, 2H), 3.34 - 3.28 (m, 4H), 2.80 (t, J= 4.0 Hz, 1H), 2.45 - 2.27 (m, 2H), 0.87 (s, 9H), 0.05 (s, 6H).

Step-4:

[1036] To a stirred mixture of 4,4,5,5-tetramethyl-l,3,2-dioxaborolane (5.60 g, 43.78 mmol) and (R)-tert-butyl((2-methoxypent-4-yn-l-yl)oxy)dimethylsilane (4.00 g, 17.51 mmol) were added bis(cyclopenta-l,3-dien-l-yl)zirconiumbis(ylium) chloride hydride (0.90 g, 3.50 mmol) and EtsN (1.00 g, 10.50 mmol) at room temperature. The resulting solution was stirred at 60 °C for 16 h. The reaction mixture was purified by silica gel column, eluted with 0-30% ethyl acetate in petroleum ether to afford (R,E)-tert-butyl((2-methoxy-5-(4,4,5,5- tetramethyl-l,3,2-dioxaborolan-2-yl)pent-4-en-l-yl)oxy)dimethylsilane (2.30 g, 36%) as a colorless oil. MS ESI calculated for C18H37BO4S1 [M+H]⁺, 357.26. found, 357.20. 'H NMR (400 MHz, DMSO-d₆) 8 6.55 - 6.47 (m, 1H), 5.38 (dt, J= 18.0, 1.6 Hz, 1H), 3.60 - 3.50 (m, 2H), 3.36 - 3.31 (m, 4H), 2.37 - 2.20 (m, 2H), 1.19 (s, 12H), 0.87 (s, 9H), 0.04 (s, 6H).

Step-5:

[1037] To a stirred solution of (R,E)-tert-butyl((2-methoxy-5-(4,4,5,5-tetramethyl-l,3,2- dioxaborolan-2-yl)pent-4-en-l-yl)oxy)dimethylsilane (2.30 g, 6.45 mmol) in dioxane (23 mL) and H2O (2.3 mL) were added methyl 2-bromo-5-(difluoromethoxy)benzoate (2.20 g, 7.74 mmol), Pd(dppf)C12 (0.47 g, 0.64 mmol) and K2CO3 (2.70 g, 19.36 mmol) at room temperature. The resulting solution was stirred at 100 °C for 16 h. The solvents were removed under vacuum. The residue was purified by silica gel column chromatography, eluted with 0- 50% ethyl acetate in petroleum ether to afford methyl (R,E)-2-(5-((tert- butyldimethylsilyl)oxy)-4-methoxypent- 1 -en- 1 -yl)-5-(difluoromethoxy)benzoate ( 1.70 g, 61%) as a colorless oil. MS ESI calculated for CisHsyBCLSi [M+H]⁺, 431.20.; found, 431.20.

Step-6:

[1038] A solution of tert-butyl carbamate (3.71 g, 31.68 mmol) and NaOH (1.10 g, 27.59 mmol) in propan- l-ol (102 mL) and H2O (69 mL) was stirred at room temperature for 10 minutes, then DCDMH (3.02 g, 15.33 mmol) was added in portions at room temperature. After stirring at room temperature 30 minutes, a solution of methyl (R,E)-2-(5-((tert- butyldimethylsilyl)oxy)-4-methoxypent- 1 -en- 1 -yl)-5-(difluoromethoxy)benzoate (4.4 g, 10.22 mmol) in propan- l-ol (102 mL), (DHQ)2PHAL (supplier: Shanghai Accela ChemBio Co., Ltd. CAS# 140924-50-1) (0.80 g, 1.02 mmol) and Potassium osmate(VI) dihydrate (0.38 g, 1.02 mmol) were added to the mixture at 0 °C. The resulting mixture was stirred at room temperature for 16 h. The reaction was quenched with brine at room temperature. The resulting mixture was extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SC>4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-70% ethyl acetate in petroleum ether to afford tert-butyl ((3R*,4R*)-3-((R)-3-((tert- butyldimethylsilyl)oxy)-2-methoxypropyl)-7-(difluoromethoxy)-l-oxoisochroman-4- yl)carbamate (2.40 g, 44%) as a yellow oil. MS ESI calculated for C25H39F2NO?Si [M+H]⁺, 532.25; found, 532.25. Absolute stereochemistry was not determined.

Step-7:

[1039] To a stirred solution of tert-butyl ((3R*,4R*)-3-((R)-3-((tert- butyldimethylsilyl)oxy)-2-methoxypropyl)-7-(difluoromethoxy)-l-oxoisochroman-4- yl)carbamate (2.40 g, 4.51 mmol) in THF (25 mL) were added NaBH4 (0.85 g, 22.47 mmol) and boron trifluoride diethyl etherate (3.20 g, 22.57 mmol) in portions at 0 °C under nitrogen atmosphere. The resulting mixture was stirred at room temperature for 16 h. The reaction was quenched with water at 0 °C. The resulting mixture was extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous NazSCL. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-50% ethyl acetate in petroleum ether to afford tertbutyl ((3R*,4R*)-3-((R)-3-((tert-butyldimethylsilyl)oxy)-2-methoxypropyl)-7- (difluoromethoxy)isochroman-4-yl)carbamate (1.40 g, 60%) as a yellow oil. MS ESI calculated for CzsH^FzNOeSi [M+H]⁺, 518.27; found, 518.35. Absolute stereochemistry was not determined.

Step-8:

[1040] To a stirred solution of tert-butyl ((3R*,4R*)-3-((R)-3-((tert- butyldimethylsilyl)oxy)-2-methoxypropyl)-7-(difluoromethoxy)isochroman-4-yl)carbamate (1.00 g, 1.93 mmol) in THF (10 mL) was added TBAF (0.76 g, 2.90 mmol) at room temperature. The resulting mixture was stirred at room temperature for 16 h. The resulting mixture was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-80% ethyl acetate in petroleum ether to afford tertbutyl ((3R*,4R*)-7-(difluoromethoxy)-3-((R)-3-hydroxy-2-methoxypropyl)isochroman-4- yl)carbamate (0.70 g, 90%) as a yellow oil. MS ESI calculated for C19H27F2NO6 [M+H]⁺, 404.18; found, 404.10. Absolute stereochemistry was not determined.

Step-9:

[1041] To a stirred solution of tert-butyl ((3R*,4R*)-7-(difluoromethoxy)-3-((R)-3- hydroxy-2-methoxypropyl)isochroman-4-yl)carbamate (480 mg, 1.19 mmol) in toluene (5 mL) was added 2-(tributyl-X⁵-phosphaneylidene)acetonitrile (CAS No. 157141-27-0) (574 mg, 2.38 mmol) at room temperature under nitrogen atmosphere. The resulting mixture was stirred at 110 °C for 16 h. The resulting mixture was concentrated under vacuum. The residue was purified by silica gel column chromatography, eluted with 0-50% ethyl acetate in petroleum ether to afford tert-butyl (3R,4aR*,10bR*)-8-(difhioromethoxy)-3-methoxy- 2,3,4,4a,6,10b-hexahydro-lH-isochromeno[4,3-b]pyridine-l-carboxylate (350 mg, 76%) as a yellow oil. MS ESI calculated for C19H25F2NO5 [M+H]⁺, 386.17; found, 386.15. Absolute stereochemistry was not determined.

Step- 10:

[1042] A solution of tert-butyl (3R,4aR*,10bR*)-8-(difluoromethoxy)-3-methoxy- 2,3,4,4a,6,10b-hexahydro-lH-isochromeno[4,3-b]pyridine-l-carboxyIate (350 mg, 0.91 mmol) and hydrogen chloride (4.0 M in ethyl acetate) (4 mL) was stirred at room temperature for 1 h. The resulting mixture was concentrated under reduced pressure to afford (3R,4aR*, 10bR*)-8-(difluoromethoxy)-3-methoxy-2,3,4,4a,6, 1 Ob-hexahydro- 1H- isochromeno[4,3-b]pyridine (A30) (300 mg, crude) as a grey oil. MS ESI calculated for C14H17F2NO3 [M+H]⁺, 286.12; found, 286.15. *H NMR (400 MHz, DMSO-d₆) 8 9.86 (br, 1H), 8.64 (br, 1H), 7.74 (d, J= 8.4 Hz, 1H), 7.29 (t, J = 73.8 Hz, 1H), 7.17 (dd, J= 8.4, 2.6 Hz, 1H), 7.03 (d, J= 2.4 Hz, 1H), 4.97 - 4.61 (m, 2H), 4.35 - 4.31 (m, 1H), 3.97 - 3.96 (m, 1H), 3.68 - 3.67 (m, 1H), 3.30 - 3.23 (m, 5H), 2.37 - 2.32 (m, 1H), 2.02 - 1.99 (m, 1H). Absolute stereochemistry was not determined.

Intermediate A32, isomer 1: rel-tert-butyl (4aR,10bR)-8-(trifluoromethyl)-l,2,3,4a,5,10b- hexahydro-4H-chromeno[3,4-b]pyrazine-4-carboxylate, isomerl

A32, isomer 1

Step-1:

[1043] To a solution of 7-(trifluoromethyl)chroman-4-one (24.00 g, 111.02 mmol) in MeOH (240 mL) was added NaBH4 (8.40 g, 222.05 mmol) in portions at 0 °C. The mixture was stirred at room temperature for 2 h. The mixture was quenched with water and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under vacuum. The residue was purified by flash column chromatography with 0-48% ethyl acetate in petroleum ether to afford 7- (trifhioromethyl)chroman-4-ol (23.20 g, 95%) as a white solid. MS ESI calculated for C10H9F3O2 [M+H]⁺, 219.06; found, 219.05. Step-2:

[1044] To a solution of 7-(tifluoromethyl)chroman-4-ol (22.20 g, 101.75 mmol) in toluene (220 mL) was added TsOH (35.04 g, 203.50 mmol) at room temperature. The mixture was stirred at 100 °C for 0.5 h. The mixture was quenched with water and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under vacuum. The residue was purified by flash column chromatography with 0-60% ethyl acetate in petroleum ether to afford 7-(trifluoromethyl)- 2H-chromene (10.10 g, 49%) as a colorless oil. MS ESI calculated for C10H7F3O [M+H]⁺, 201.04; found, 201.00.

Step-3:

[1045] A solution of 7-(trifhioromethyl)-2H-chromene (10.10 g, 50.46 mmol) in THF (75.0 mL) and H2O (25.0 mL) was added NBS (9.88 g, 55.50 mmol) at 0 °C, then the mixture was stirred at 0 °C for 16 h. The mixture was quenched with water and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under vacuum. The residue was purified by flash column chromatography with 0 ~ 45% ethyl acetate in petroleum ether to afford intermidiate (8.70 g) yellow oil, which was dissolved in MeOH (8.0 mL), then ammonium hydroxide (28% in water) (80.0 mL) was added. The mixture was stirred at room temperature for 2 h. The mixture was diluted with water and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under vacuum. The residue was purified by flash column chromatography with 0 ~ 45% ethyl acetate in petroleum ether to afford a 1 : 1 mixture of (3R,4S)-4-amino-7- (trifhioromethyl)chroman-3-ol and (3S,4R)-4-amino-7-(trifluoromethyl)chroman-3-ol (4.8 g, 74%) as a colorless oil. MS ESI calculated for C10H10F3NO2 [M+H]⁺, 234.07; found, 234.10.

Step-4:

[1046] A solution of a 1:1 mixture of (3R,4S)-4-amino-7-(trifluoromethyl)chroman-3-ol and (3S,4R)-4-amino-7-(trifluoromethyl)chroman-3-ol and tert-butyl N-(2- oxoethyl)carbamate (2.18 g, 13.72 mmol) in MeOH (40.0 mL) was stirred at room temperature for 2 h. NaBH4 (1.04 g, 27.44 mmol) was added in portions to above solution. Then the mixture was stirred at room temperature for 2 h. The mixture was quenhed by water and extracted with ethyl acetate, dried over anhydrous sodium sulfate, filtered, and concentrated under vacuum. The residue was purified by flash column chromatography with 0-80% ethyl acetate in petroleum ether to afford a 1:1 mixture of tert-butyl (2-(((3R,4S)-3- hydroxy-7-(trifluoromethyl)chroman-4-yl)amino)ethyl)carbamate and tert-butyl (2-(((3S,4R)- 3-hydroxy-7-(trifhioromethyl)chroman-4-yl)amino)ethyl)carbamate (3.10 g, 60%) as a white solid. MS ESI calculated for C17H23F3N2O4 [M+H]⁺, 377.16, found, 377.20.

Step-5:

[1047] To a solution of a 1 : 1 mixture of tert-butyl (2-(((3R,4S)-3-hydroxy-7- (trifluoromethyl)chroman-4-yl)amino)ethyl)carbamate and tert-butyl (2-(((3S,4R)-3-hydroxy- 7-(trifhioromethyl)chroman-4-yl)amino)ethyl)carbamate and NaHCCh (9.44 g, 112.38 mmol) in 1,4-dioxane (150.0 mL) was added CbzCl (9.59 g, 56.19 mmol) dropwise at 0 °C. The mixture was stirred at room temperature for 2 h. The mixture was quenched with water and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under vacuum. The residue was purified by flash column chromatography with 0 ~ 60% ethyl acetate in petroleum ether to afford a 1:1 mixtire of benzyl (2-((tert-butoxycarbonyl)amino)ethyl)((3R,4S)-3-hydroxy-7- (trifhioromethyl)chroman-4-yl)carbamate and benzyl (2-((tert- butoxycarbonyl)amino)ethyl)((3S,4R)-3-hydroxy-7-(trifluoromethyl)chroman-4-yl)carbamate (15.4 g, 80%) as a colorless oil. MS ESI calculated for C25H29F3N2O6 [M+H]⁺, 511.20; found, 511.20.

Step-6:

[1048] A solution of a 1:1 mixtire of benzyl (2-((tert- butoxycarbonyl)amino)ethyl)((3R,4S)-3-hydroxy-7-(trifluoromethyl)chroman-4-yl)carbamate and benzyl (2-((tert-butoxycarbonyl)amino)ethyl)((3S,4R)-3-hydroxy-7-

(trifluoromethyl)chroman-4-yl)carbamate (15.00 g, 29.38 mmol) and HC1 (4M in 1,4- dioxane) (150.0 mL) was stirred at room temperature for 2 h. The mixture was concentrated to afford a 1:1 mixture of benzyl (2-aminoethyl)((3R,4S)-3-hydroxy-7-

(trifhioromethyl)chroman-4-yl)carbamate and benzyl (2-aminoethyl)((3S,4R)-3-hydroxy-7- (trifhioromethyl)chroman-4-yl)carbamate (15.00 g, crude) as a yellow oil. MS ESI calculated for C20H21F3N2O4 [M+H]⁺, 411.15; found, 411.15.

Step-7:

[1049] To a solution of a 1 : 1 mixture of benzyl (2-aminoethyl)((3R,4S)-3-hydroxy-7- (trifluoromethyl)chroman-4-yl)carbamate and benzyl (2-aminoethyl)((3S,4R)-3-hydroxy-7- (trifluoromethyl)chroman-4-yl)carbamate (15.00 g, 36.550 mmol) and pyridine (8.67 g, 109.65 mmol) in DCM (150.0 mL) was added 2-nitrobenzenesulfonyl chloride (9.72 g, 43.86 mmol) at 0 °C. Then the mixture was stirred at room temperature for 4 h. The mixture was quenched with water and extracted with DCM. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under vacuum. The residue was purified by flash column chromatography with 0-80% ethyl acetate in petroleum ether to afford a 1:1 mixture of benzyl ((3R,4S)-3-hydroxy-7- (trifhioromethyl)chroman-4-yl)(2-((2-nitrophenyl)sulfonamido)ethyl)carbamate and benzyl ((3S,4R)-3-hydroxy-7-(trifluoromethyl)chroman-4-yl)(2-((2- nitrophenyl)sulfonamido)ethyl)carbamate (6.80 g, 31%) as a yellow oil. MS ESI calculated for C26H24F3N3O8S [M+H]⁺, 596.12; found, 596.15.

Step-8:

[1050] To a solution of a 1:1 mixture of benzyl ((3R,4S)-3-hydroxy-7- (trifluoromethyl)chroman-4-yl)(2-((2-nitrophenyl)sulfonamido)ethyl)carbamate and benzyl ((3S,4R)-3-hydroxy-7-(trifhioromethyl)chroman-4-yl)(2-((2- nitrophenyl)sulfonamido)ethyl)carbamate (6.80 g, 5.03 mmol) and PPha (4.48 g, 7.55 mmol) in THF (68.0 mL) was added DIEA (4.42 g, 15.11 mmol) at 0 °C under nitrogen atmosphere.The mixture was stirred at room temperature for 4 h. The mixture was quenched with water and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under vacuum. The residue was purified by flash column chromatography with 0-25% ethyl acetate in petroleum ether to afford a 1:1 mixture of benzyl (4aS,10bS)-4-((2-nitrophenyl)sulfonyl)-8- (trifhioromethyl)-3,4,4a,10b-tetrahydro-2H-chromeno[3,4-b]pyrazine-l(5H)-carboxylate and benzyl (4aR,10bR)-4-((2-nitrophenyl)sulfonyl)-8-(trifluoromethyl)-3,4,4a,10b-tetrahydro- 2H-chromeno[3,4-b]pyrazine-l(5H)-carboxylate (4.10 g, 79%) as a yellow oil. MS ESI calculated for C26H22F3N3O7S [M+H]⁺, 578.11; found, 578.10.

Step-9:

[1051] To a stirred solution of a 1:1 mixture of benzyl (4aS,10bS)-4-((2- nitrophenyl)sulfonyl)-8-(trifluoromethyl)-3,4,4a,10b-tetrahydro-2H-chromeno[3,4- b]pyrazine-l(5H)-carboxylate and benzyl (4aR,10bR)-4-((2-nitrophenyl)sulfonyl)-8- (trifhioromethyl)-3,4,4a,10b-tetrahydro-2H-chromeno[3,4-b]pyrazine-l(5H)-carboxylate (4.10 g, 0.69 mmol) in DMF (40.0 mL) were added LiOH (1.70 g, 6.93 mmol) and 2- sulfanylacetic acid (3.80 g, 4.15 mmol) at room temperature. The mixture was stirred at room temperature for 4 h under nitrogen atmosphere. The mixture was quenched with water and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under vacuum. The residue was purified by flash column chromatography with 0-55% ethyl acetate in petroleum ether to afford a 1:1 mixture of benzyl (4aS,10bS)-8-(trifluoromethyl)-3,4,4a,10b-tetrahydro-2H-chromeno[3,4- b]pyrazine-l(5H)-carboxylate and benzyl (4aS,10bS)-8-(trifhioromethyl)-3,4,4a,10b- tetrahydro-2H-chromeno[3,4-b]pyrazine-l(5H)-carboxylate (1.90 g, 73%) as a yellow oil. MS ESI calculated for C20H19F3N2O3 [M+H]⁺, 393.13; found, 393.15.

Step- 10:

[1052] To a stirred solution of a 1:1 mixture of benzyl (4aS,10bS)-8-(trifluoromethyl)- 3,4,4a, 10b-tetrahydro-2H-chromeno[3,4-b]pyrazine- 1 (5H)-carboxylate and benzyl (4aS, 10bS)-8-(trifluoromethyl)-3,4,4a, 10b-tetrahydro-2H-chromeno[3,4-b]pyrazine- 1 (5H)- carboxylate (1.90 g, 4.84 mmol) in THF (20.0 mL) were added TEA (1.47 g, 14.52 mmol) and BociO (1.59 g, 7.26 mmol) at room temperature. The mixture was stirred at room temperature for 4 h. The mixture was quenched with water and extracted with DCM. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under vacuum. The residue was purified by flash column chromatography with 0-55% ethyl acetate in petroleum ether to afford a 1:1 mixture of 1- benzyl 4-(tert-butyl) (4aS,10bS)-8-(trifhioromethyl)-2,3,4a,10b-tetrahydro-4H-chromeno[3,4- b]pyrazine-l ,4(5H)-dicarboxylate and 1-benzyl 4-(tert-butyl) (4aR,10bR)-8- (trifluoromethyl)-2,3,4a,10b-tetrahydro-4H-chromeno[3,4-b]pyrazine-l,4(5H)-dicarboxylate (1.50 g, 63 %) as a yellow oil. MS ESI calculated for C25H27F3N2O5 [M+H]⁺, 493.19; found, 493.19.

Step-11:

[1053] A 1:1 mixture of 1-benzyl 4-(tert-butyl) (4aS,10bS)-8-(trifluoromethyl)-2,3,4a,10b- tetrahydro-4H-chromeno[3,4-b]pyrazine-l,4(5H)-dicarboxylate and 1-benzyl 4-(tert-butyl) (4aR, 10bR)-8-(trifluoromethyl)-2,3,4a, 10b-tetrahydro-4H-chromeno[3,4-b]pyrazine- 1 ,4(5H)- dicarboxylate (1.5 g, 3.04 mmol) was separated by Prep-Chiral SFC with the following conditions [Column: CHIRALPAK PAK AD-H, 30*250mm; Mobile Phase A: CO2, Mobile Phase B: MeOH; Flow rate: 100 mL/min; Gradient (B%): isocratic 20% B; RTl(min): 2.6; RT2(min): 4.8; Sample Solvent: MEOH] to afford rel-l-benzyl 4-(tert-butyl) (4aR,10bR)-8- (trifhioromethyl)-2,3,4a,10b-tetrahydro-4H-chromeno[3,4-b]pyrazine-l,4(5H)-dicarboxylate, isomer 1 (600 mg, 40%) as a colorless oil. MS ESI calculated for C25H27F3N2O5 [M+l]⁺, 493.19; found, 493.20. 'H NMR (400 MHz, DMSO- ₆) 57.52 - 7.24 (m, 7H), 7.23 - 7.17 (m, 1H), 5.77 (d, J = 6.8 Hz, 1H), 5.34 - 5.16 (m, 2H), 4.55 - 4.49 (m, 1H), 4.40 - 4.26 (m, 2H), 3.97 - 3.84 (m, 1H), 3.55 - 3.49 (m, 1H), 3.21 - 3.15 (m, 1H), 2.68 - 2.59 (m, 1H), 1.44 (s, 9H). Absolute stereochemistry was not determined.

[1054] The chiral resolution also afford rel-l-benzyl 4-(tert-butyl) (4aR,10bR)-8- (trifluoromethyl)-2,3,4a,10b-tetrahydro-4H-chromeno[3,4-b]pyrazine-l,4(5H)-dicarboxylate, isomer 2 (610.0 mg, 41%) as a colorless oil. MS ESI calculated for C25H27F3N2O5 [M+l]⁺, 493.19; found, 493.20. 'H NMR (400 MHz, DMSO-d₆) 8 7.52 - 7.24 (m, 7H), 7.23 - 7.17 (m, 1H), 5.77 (d, J = 6.8 Hz, 1H), 5.34 - 5.16 (m, 2H), 4.55 - 4.49 (m, 1H), 4.40 - 4.26 (m, 2H), 3.97 - 3.84 (m, 1H), 3.55 - 3.49 (m, 1H), 3.21 - 3.15 (m, 1H), 2.68 - 2.59 (m, 1H), 1.44 (s, 9H). Absolute stereochemistry was not determined.

Step- 12:

A32, isomer 1

[1055] To a solution of rel-l-benzyl 4-(tert-butyl) (4aR,10bR)-8-(trifluoromethyl)- 2,3,4a,10b-tetrahydro-4H-chromeno[3,4-b]pyrazine-l,4(5H)-dicarboxylate, isomer 1 (100 mg, 0.40 mmol) in isopropanol (2.0 mL) was added Pd/C (5% active on carbon) (22 mg) at room temperature. The mixture was stirred at room temperature for 4 h under hydrogen atmosphere (1 atm.). The solids were filtered off. The filtrate was concentrated under vacuum to afford rel-tert-butyl (4aR,10bR)-8-(trifluoromethyl)-l,2,3,4a,5,10b-hexahydro-4H- chromeno[3,4-b]pyrazine-4-carboxylate, isomer 1 (A32, isomer 1) (100.0 mg, crude) as a colorless oil that was used directly in next reaction. MS ESI calculated for C17H21F3N2O3 [M+H]⁺, 359.15; found, 359.15. Absolute stereochemistry was not determined. Intermediate A32, isomer 1: rel-tert-butyl (4aR,10bR)-8-(trifluoromethyl)-l,2,3,4a,5,10b- hexahydro-4H-chromeno[3,4-b]pyrazine-4-carboxylate, isomerl

A32, isomer 1

Step-1:

[1056] To a solution of 7-(tifluoromethyl)chroman-4-one (24.00 g, 111.02 mmol) in MeOH (240 mL) was added NaBH4 (8.40 g, 222.05 mmol) in portions at 0 °C. The mixture was stirred at room temperature for 2 h. The mixture was quenched with water and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under vacuum. The residue was purified by flash column chromatography with 0-48% ethyl acetate in petroleum ether to afford 7- (trifhioromethyl)chroman-4-ol (23.20 g, 95%) as a white solid. MS ESI calculated for C10H9F3O2 [M+H]⁺, 219.06; found, 219.05.

Step-2:

[1057] To a solution of 7-(trifhioromethyl)chroman-4-ol (22.20 g, 101.75 mmol) in toluene (220 mL) was added TsOH (35.04 g, 203.50 mmol) at room temperature. The mixture was stirred at 100 °C for 0.5 h. The mixture was quenched with water and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under vacuum. The residue was purified by flash column chromatography with 0-60% ethyl acetate in petroleum ether to afford 7-(trifluoromethyl)- 2H-chromene (10.10 g, 49%) as a colorless oil. MS ESI calculated for C10H7F3O [M+H]⁺, 201.04; found, 201.00.

Step-3:

[1058] A solution of 7-(trifhioromethyl)-2H-chromene (10.10 g, 50.46 mmol) in THF (75.0 mL) and H2O (25.0 mL) was added NBS (9.88 g, 55.50 mmol) at 0 °C, then the mixture was stirred at 0 °C for 16 h. The mixture was quenched with water and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under vacuum. The residue was purified by flash column chromatography with 0 ~ 45% ethyl acetate in petroleum ether to afford intermidiate (8.70 g) yellow oil, which was dissolved in MeOH (8.0 mL), then ammonium hydroxide (28% in water) (80.0 mL) was added. The mixture was stirred at room temperature for 2 h. The mixture was diluted with water and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under vacuum. The residue was purified by flash column chromatography with 0 ~ 45% ethyl acetate in petroleum ether to afford a 1 : 1 mixture of (3R,4S)-4-amino-7- (trifhioromethyl)chroman-3-ol and (3S,4R)-4-amino-7-(trifluoromethyl)chroman-3-ol (4.8 g, 74%) as a colorless oil. MS ESI calculated for C10H10F3NO2 [M+H]⁺, 234.07; found, 234.10.

Step-4:

[1059] A solution of a 1:1 mixture of (3R,4S)-4-amino-7-(trifluoromethyl)chroman-3-ol and (3S,4R)-4-amino-7-(trifluoromethyl)chroman-3-ol and tert-butyl N-(2- oxoethyl)carbamate (2.18 g, 13.72 mmol) in MeOH (40.0 mL) was stirred at room temperature for 2 h. NaBFL (1.04 g, 27.44 mmol) was added in portions to above solution. Then the mixture was stirred at room temperature for 2 h. The mixture was quenhed by water and extracted with ethyl acetate, dried over anhydrous sodium sulfate, filtered, and concentrated under vacuum. The residue was purified by flash column chromatography with 0-80% ethyl acetate in petroleum ether to afford a 1:1 mixture of tert-butyl (2-(((3R,4S)-3- hydroxy-7-(trifhioromethyl)chroman-4-yl)amino)ethyl)carbamate and tert-butyl (2-(((3S,4R)- 3-hydroxy-7-(trifhioromethyl)chroman-4-yl)amino)ethyl)carbamate (3.10 g, 60%) as a white solid. MS ESI calculated for C17H23F3N2O4 [M+H]⁺, 377.16, found, 377.20.

Step-5:

[1060] To a solution of a 1:1 mixture of tert-butyl (2-(((3R,4S)-3-hydroxy-7- (trifhioromethyl)chroman-4-yl)amino)ethyl)carbamate and tert-butyl (2-(((3S,4R)-3-hydroxy- 7-(trifhioromethyl)chroman-4-yl)amino)ethyl)carbamate and NaHCCh (9.44 g, 112.38 mmol) in 1,4-dioxane (150.0 mL) was added CbzCl (9.59 g, 56.19 mmol) dropwise at 0 °C. The mixture was stirred at room temperature for 2 h. The mixture was quenched with water and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under vacuum. The residue was purified by flash column chromatography with 0 ~ 60% ethyl acetate in petroleum ether to afford a 1:1 mixtire of benzyl (2-((tert-butoxycarbonyl)amino)ethyl)((3R,4S)-3-hydroxy-7- (trifhioromethyl)chroman-4-yl)carbamate and benzyl (2-((tert- butoxycarbonyl)amino)ethyl)((3S,4R)-3-hydroxy-7-(trifluoromethyl)chroman-4-yl)carbamate (15.4 g, 80%) as a colorless oil. MS ESI calculated for C25H29F3N2O6 [M+H]⁺, 511.20; found, 511.20.

Step-6:

[1061] A solution of a 1:1 mixtire of benzyl (2-((tert- butoxycarbonyl)amino)ethyl)((3R,4S)-3-hydroxy-7-(trifluoromethyl)chroman-4-yl)carbamate and benzyl (2-((tert-butoxycarbonyl)amino)ethyl)((3S,4R)-3-hydroxy-7-

(trifluoromethyl)chroman-4-yl)carbamate and benzyl (2-aminoethyl)((3S,4R)-3-hydroxy-7- (trifluoromethyl)chroman-4-yl)carbamate (15.00 g, crude) as a yellow oil. MS ESI calculated for C20H21F3N2O4 [M+H]⁺, 411.15; found, 411.15.

[1062] To a solution of a 1 : 1 mixture of benzyl (2-aminoethyl)((3R,4S)-3-hydroxy-7- (trifluoromethyl)chroman-4-yl)carbamate and benzyl (2-aminoethyl)((3S,4R)-3-hydroxy-7- (trifluoromethyl)chroman-4-yl)carbamate (15.00 g, 36.550 mmol) and pyridine (8.67 g, 109.65 mmol) in DCM (150.0 mL) was added 2-nitrobenzenesulfonyl chloride (9.72 g, 43.86 mmol) at 0 °C. Then the mixture was stirred at room temperature for 4 h. The mixture was quenched with water and extracted with DCM. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under vacuum. The residue was purified by flash column chromatography with 0-80% ethyl acetate in petroleum ether to afford a 1:1 mixture of benzyl ((3R,4S)-3-hydroxy-7- (trifluoromethyl)chroman-4-yl)(2-((2-nitrophenyl)sulfonamido)ethyl)carbamate and benzyl ((3S,4R)-3-hydroxy-7-(trifluoromethyl)chroman-4-yl)(2-((2- nitrophenyl)sulfonamido)ethyl)carbamate (6.80 g, 31%) as a yellow oil. MS ESI calculated for C26H24F3N3O8S [M+H]⁺, 596.12; found, 596.15.

Step-8:

[1063] To a solution of a 1 : 1 mixture of benzyl ((3R,4S)-3-hydroxy-7- (trifluoromethyl)chroman-4-yl)(2-((2-nitrophenyl)sulfonamido)ethyl)carbamate and benzyl ((3S,4R)-3-hydroxy-7-(trifluoromethyl)chroman-4-yl)(2-((2- nitrophenyl)sulfonamido)ethyl)carbamate (6.80 g, 5.03 mmol) and PPhs (4.48 g, 7.55 mmol) in THF (68.0 mL) was added DIEA (4.42 g, 15.11 mmol) at 0 °C under nitrogen atmosphere.The mixture was stirred at room temperature for 4 h. The mixture was quenched with water and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under vacuum. The residue was purified by flash column chromatography with 0-25% ethyl acetate in petroleum ether to afford a 1:1 mixture of benzyl (4aS,10bS)-4-((2-nitrophenyl)sulfonyl)-8- (trifhioromethyl)-3,4,4a,10b-tetrahydro-2H-chromeno[3,4-b]pyrazine-l(5H)-carboxylate and benzyl (4aR,10bR)-4-((2-nitrophenyl)sulfonyl)-8-(trifluoromethyl)-3,4,4a,10b-tetrahydro- 2H-chromeno[3,4-b]pyrazine-l(5H)-carboxylate (4.10 g, 79%) as a yellow oil. MS ESI calculated for C26H22F3N3O7S [M+H]⁺, 578.11; found, 578.10.

Step-9:

[1064] To a stirred solution of a 1 : 1 mixture of benzyl (4aS, 10bS)-4-((2- nitrophenyl)sulfonyl)-8-(trifluoromethyl)-3,4,4a,10b-tetrahydro-2H-chromeno[3,4- b]pyrazine-l(5H)-carboxylate and benzyl (4aR,10bR)-4-((2-nitrophenyl)sulfonyl)-8- (trifluoromethyl)-3,4,4a,10b-tetrahydro-2H-chromeno[3,4-b]pyrazine-l(5H)-carboxylate (4.10 g, 0.69 mmol) in DMF (40.0 mL) were added LiOH (1.70 g, 6.93 mmol) and 2- sulfanylacetic acid (3.80 g, 4.15 mmol) at room temperature. The mixture was stirred at room temperature for 4 h under nitrogen atmosphere. The mixture was quenched with water and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under vacuum. The residue was purified by flash column chromatography with 0-55% ethyl acetate in petroleum ether to afford a 1:1 mixture of benzyl (4aS,10bS)-8-(trifhioromethyl)-3,4,4a,10b-tetrahydro-2H-chromeno[3,4- b]pyrazine-l(5H)-carboxylate and benzyl (4aS,10bS)-8-(trifluoromethyl)-3,4,4a,10b- tetrahydro-2H-chromeno[3,4-b]pyrazine-l(5H)-carboxylate (1.90 g, 73%) as a yellow oil. MS ESI calculated for C20H19F3N2O3 [M+H]⁺, 393.13; found, 393.15.

Step- 10:

[1065] To a stirred solution of a 1:1 mixture of benzyl (4aS,10bS)-8-(trifhioromethyl)- 3,4,4a, 10b-tetrahydro-2H-chromeno[3,4-b]pyrazine- 1 (5H)-carboxylate and benzyl

(4aS, 10bS)-8-(trifhioromethyl)-3,4,4a, 10b-tetrahydro-2H-chromeno[3,4-b]pyrazine- 1 (5H)- carboxylate (1 .90 g, 4.84 mmol) in THF (20.0 mL) were added TEA (1.47 g, 14.52 mmol) and BOC2O (1.59 g, 7.26 mmol) at room temperature. The mixture was stirred at room temperature for 4 h. The mixture was quenched with water and extracted with DCM. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under vacuum. The residue was purified by flash column chromatography with 0-55% ethyl acetate in petroleum ether to afford a 1:1 mixture of 1- benzyl 4-(tert-butyl) (4aS,10bS)-8-(trifhioromethyl)-2,3,4a,10b-tetrahydro-4H-chromeno[3,4- b]pyrazine-l,4(5H)-dicarboxylate and 1-benzyl 4-(tert-butyl) (4aR,10bR)-8- (trifhioromethyl)-2,3,4a,10b-tetrahydro-4H-chromeno[3,4-b]pyrazine-l,4(5H)-dicarboxylate (1.50 g, 63 %) as a yellow oil. MS ESI calculated for C25H27F3N2O5 [M+H]⁺, 493.19; found, 493.19.

Step-11:

[1066] A 1:1 mixture of 1-benzyl 4-(tert-butyl) (4aS,10bS)-8-(trifhioromethyl)-2,3,4a,10b- tetrahydro-4H-chromeno[3,4-b]pyrazine-l,4(5H)-dicarboxylate and 1-benzyl 4-(tert-butyl) (4aR, 10bR)-8-(trifhioromethyl)-2,3,4a, 10b-tetrahydro-4H-chromeno[3,4-b]pyrazine- 1 ,4(5H)- dicarboxylate (1.5 g, 3.04 mmol) was separated by Prep-Chiral SFC with the following conditions [Column: CHIRALPAK PAK AD-H, 30*250 mm; Mobile Phase A: CO2, Mobile Phase B: MeOH; Flow rate: 100 mL/min; Gradient (B%): isocratic 20% B; RTl(min): 2.6; RT2(min): 4.8; Sample Solvent: MeOH] to afford rel- 1-benzyl 4-(tert-butyl) (4aR,10bR)-8- (trifhioromethyl)-2,3,4a, 10b-tetrahydro-4H-chromeno [3 ,4-b]pyrazine- 1 ,4(5H)-dicarboxylate, isomer 1 (600 mg, 40%) as a colorless oil. MS ESI calculated for C25H27F3N2O5 [M+l]⁺, 493.19; found, 493.20. 'H NMR (400 MHz, DMSO-d₆) 67.52 - 7.24 (m, 7H), 7.23 - 7.17 (m, 1H), 5.77 (d, J = 6.8 Hz, 1H), 5.34 - 5.16 (m, 2H), 4.55 - 4.49 (m, 1H), 4.40 -4.26 (m, 2H), 3.97 - 3.84 (m, 1H), 3.55 - 3.49 (m, 1H), 3.21 - 3.15 (m, 1H), 2.68 - 2.59 (m, 1H), 1.44 (s, 9H). Absolute stereochemistry was not determined.

[1067] The chiral resolution also afforded rel-l-benzyl 4-(tert-butyl) (4aR,10bR)-8- (trifhioromethyl)-2,3,4a,10b-tetrahydro-4H-chromeno[3,4-b]pyrazine-l,4(5H)-dicarboxylate, isomer 2 (610.0 mg, 41%) as a colorless oil. MS ESI calculated for C25H27F3N2O5 [M+l]⁺, 493.19; found, 493.20. 'H NMR (400 MHz, DMSO- ₆) 87.52 - 7.24 (m, 7H), 7.23 - 7.17 (m, 1H), 5.77 (d, J = 6.8 Hz, 1H), 5.34 - 5.16 (m, 2H), 4.55 - 4.49 (m, 1H), 4.40 - 4.26 (m, 2H), 3.97 - 3.84 (m, 1H), 3.55 - 3.49 (m, 1H), 3.21 - 3.15 (m, 1H), 2.68 - 2.59 (m, 1H), 1.44 (s, 9H). Absolute stereochemistry was not determined.

Step- 12:

A32, isomer 1

[1068] To a solution of rel-l-benzyl 4-(tert-butyl) (4aR,10bR)-8-(trifluoromethyl)- 2,3,4a,10b-tetrahydro-4H-chromeno[3,4-b]pyrazine-l,4(5H)-dicarboxylate, isomer 1 (100 mg, 0.40 mmol) in isopropanol (2.0 mL) was added Pd/C (5% active on carbon) (22 mg) at room temperature. The mixture was stirred at room temperature for 4 h under hydrogen atmosphere (1 atm.). The solids were filtered off. The filtrate was concentrated under vacuum to afford rel-tert-butyl (4aR,10bR)-8-(trifhioromethyl)-l,2,3,4a,5,10b-hexahydro-4H- chromeno[3,4-b]pyrazine-4-carboxylate, isomer 1 (A32, isomer 1) (100.0 mg, crude) as a colorless oil that was used directly in next reaction. MS ESI calculated for C17H21F3N2O3 [M+H]⁺, 359.15; found, 359.15. Absolute stereochemistry was not determined.

Intermediate A32, isomer 2: rel-tert-butyl (4aR,10bR)-8-(trifluoromethyl)-l,2,3,4a,5,10b- hexahydro-4H-chromeno[3,4-b]pyrazine-4-carboxylate, isomer 2

„ Boc A?

A32, isomer 2

[1069] To a solution of rel-l-benzyl 4-(tert-butyl) (4aR,10bR)-8-(trifluoromethyl)- 2,3,4a,10b-tetrahydro-4H-chromeno[3,4-b]pyrazine-l,4(5H)-dicarboxylate, isomer 2 (100 mg, 0.40 mmol) in isopropanol (2.0 mL) was added Pd/C (5% active on carbon) (21 mg) at room temperature. The mixture was stirred at room temperature for 4 h under hydrogen atmosphere (1 atm.). The solids was filtered off. The filtrate was concentrated under vacuum to afford rel-tert-butyl (4aR,10bR)-8-(trifhioromethyl)-l,2,3,4a,5,10b-hexahydro-4H- chromeno[3,4-b]pyrazine-4-carboxylate, isomer 2 (A32, isomer 2) (100.0 mg, crude) as a colorless oil. MS ESI calculated for C17H21F3N2O3 [M+H]⁺, 359.15; found, 359.15. Absolute stereochemistry was not determined.

Intermediate A33: rel-(4aS,9bS)-l,2,3,4,4a,9b-hexahydrofuro[2,3-b:4,5-b']dipyridine-7- carbonitrile

A33

Step-1:

[1070] To a stirred solution of 3-bromo-2,6-dichloropyridine (25.00 g, 110.19 mmol) and (E)-tert-butyldiphenyl((5-(4,4,5,5-tetramethyl-l,3,2-dioxaborolan-2-yl)pent-4-en-l- yl)oxy)silane (54.60 g, 121.20 mmol) in dioxane (250 mL) and H2O (25 mL) were added Pd(dppf)Ch (8.06 g, 11.01 mmol) and K2CO3 (45.69 g, 330.57 mmol) at room temperature under nitrogen atmosphere. The resulting mixture was stirred at 100 °C for 16 h under nitrogen atmosphere. The resulting mixture was extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SC>4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-30% EtOAc in PE to afford (E)-3-(5-((tert- butyldiphenylsilyl)oxy)pent-l-en-l-yl)-2,6-dichloropyridine (44.6 g, 94%) as a yellow oil. MS ESI calculated for C26H₂₉C12NOSi [M+H]⁺, 470.14 ; found, 470.20.

Step-2:

[1071] To a stirred solution of tert-butyl carbamate (34.42 g, 293.85 mmol) in propan-l-ol (368 mL) was added a solution of NaOH (10.24 g, 255.93 mmol) in H2O (322 mL) at room temperature under nitrogen atmosphere. The resulting mixture was stirred at room temperature for 10 minutes. Then DCDMH (37.35 g, 189.58 mmol) was added in portions at room temperature. After stirring for 30 minutes, a solution of (DHQ)2PHAL (supplier: Shanghai Accela ChemBio Co., Ltd. CAS# 140924-50-1) (7.38 g, 9.47 mmol) in propan-l-ol (95 mL), a solution of (E)-3-(5-((tert-butyldiphenylsilyl)oxy)pent-l-en-l-yl)-2,6- dichloropyridine (44.60 g, 94.79 mmol) in propan-l-ol (95 mL) and Potassium osmate (VI) dihydrate (3.49 g, 9.47 mmol) were added to the mixture at 0 °C. The resulting mixture was stirred at room temperature for 16 h. The resulting mixture was diluted by water and extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SO₄. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-40% EtOAc in PE to afford rel-tert-butyl ((lS,2S)-5-((tert-butyldiphenylsilyl)oxy)-l-(2,6-dichloropyridin-3-yl)- 2-hydroxypentyl)carbamate (16.00 g, 95%) as a green oil. MS ESI calculated for C3iH4oCi2N₂0₄Si [M+H]⁺, 603.21 ; found, 603.25. Absolute stereochemistry was not determined.

Step-3:

[1072] To a stirred solution of rel-tert-butyl ((lS,2S)-5-((tert-butyldiphenylsilyl)oxy)-l- (2,6-dichloropyridin-3-yl)-2-hydroxypentyl)carbamate (3.00 g, 4.97 mmol) in THF (30 mL) was added TBAF (2.60 g, 9.94 mmol) at room temperature under nitrogen atmosphere. The resulting mixture was stirred at room temperature for 16 h under nitrogen atmosphere. The resulting mixture was concentrated under vacuum, The residue was purified by silica gel column chromatography, eluted with 0-80% EtOAc in PE to afford rel-tert-butyl ((1S,2S)-1- (2,6-dichloropyridin-3-yl)-2,5-dihydroxypentyl)carbamate (1.30 g, 98%) as a yellow oil. MS ESI calculated for C15H22C12N2O4 [M+H]⁺, 365.10; found, 365.10. Absolute stereochemistry was not determined.

Step-4:

[1073] To a stirred solution of rel-tert-butyl ((lS,2S)-l-(2,6-dichloropyridin-3-yl)-2,5- dihydroxypentyl)carbamate (1.30 g, 3.55 mmol) and Imidazole (0.97 g, 14.23 mmol) in DCM (13 mL) was added TBSC1 (0.80 g, 5.33 mmol) at room temperature under nitrogen atmosphere. The resulting mixture was stirred at room temperature for 16 h. The reaction was quenched by water and extracted with CH2CI2. The combined organic layers were washed with brine, dried over anhydrous Na2SC>4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-24% EtOAc in PE to afford rel-tert-butyl ((lS,2S)-5-((tert-butyldimethylsilyl)oxy)-l-(2,6- dichloropyridin-3-yl)-2-hydroxypentyl)carbamate (1.44 g, 99%) as a light yellow oil. MS ESI calculated for C2iH36Ci2N2O4Si [M+H]⁺, 479.18; found, 479.25. Absolute stereochemistry was not determined.

Step-5:

[1074] To a stirred solution of rel-tert-butyl ((lS,2S)-5-((tert-butyldimethylsilyl)oxy)-l- (2,6-dichloropyridin-3-yl)-2-hydroxypentyl)carbamate (1.40 g, 2.92 mmol) and tert- butyl(chloro)diphenylsilane (1.20 g, 4.38 mmol) in DCM (14 mL) was added imidazole (0.80 g, 11.68 mmol) at room temperature under nitrogen atmosphere. The resulting mixture was stirred at room temperature for 16 h. The reaction was quenched by water and extracted with CH2CI2. The combined organic layers were washed with brine, dried over anhydrous Na2SO4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0 - 20% EtOAc in PE to afford rel-tert- butyl ((lS,2S)-5-((tert-butyldimethylsilyl)oxy)-2-((tert-butyldiphenylsilyl)oxy)-l-(2,6- dichloropyridin-3-yl)pentyl)carbamate (1.88 g, 73%) as a light yellow oil. MS ESI calculated for C3?H54Ci2N2O4Si2 [M+H]⁺, 717.30 ; found, 717.35. Absolute stereochemistry was not determined.

Step-6:

[1075] To a stirred solution of rel-tert-butyl ((lS,2S)-5-((tert-butyldimethylsilyl)oxy)-2- ((tert-butyldiphenylsilyl)oxy)-l-(2,6-dichloropyridin-3-yl)pentyl)carbamate (1.88 g, 2.61 mmol) in methanol (20 mL) was added TsOH (0.05 g, 0.26 mmol) at room temperature. The resulting mixture was stirred at room temperature for 16 h. The resulting mixture was concentrated under vacuum. The residue was purified by silica gel column chromatography, eluted with 0 - 30% EtOAc in PE to afford rel-tert-butyl ((lS,2S)-2-((tert- butyldiphenylsilyl)oxy)-l-(2,6-dichloropyridin-3-yl)-5-hydroxypentyl)carbamate (882 mg, 99%) as a colorless oil. MS ESI calculated for C31H40CI2N2O4S1 [M+H]⁺, 603.21; found, 603.20. Absolute stereochemistry was not determined.

Step-7: oc

[1076] To a stirred solution of rel-tert-butyl ((lS,2S)-2-((tert-butyldiphenylsilyl)oxy)-l- (2,6-dichloropyridin-3-yl)-5-hydroxypentyl)carbamate (830 mg, 1.37 mmol) in toluene (10 mL) was added 2-(tributyl- ⁵-phosphaneylidene)acetonitrile (CAS No. 157141-27-0) (663 mg, 2.75 mmol) at room temperature under nitrogen atmosphere. The resulting mixture was stirred at 110 °C for 16 h under nitrogen atmosphere. The resulting mixture was concentrated under vacuum. The residue was purified by silica gel column chromatography, eluted with 0- 10% EtOAc in PE to afford rel-tert-butyl (2S,3S)-3-((tert-butyldiphenylsilyl)oxy)-2-(2,6- dichloropyridin-3-yl)piperidine-l -carboxylate (703 mg, 90%) as a white solid. MS ESI calculated for CsiHssQz^ChSi [M+H]⁺, 585.20; found, 585.35. Absolute stereochemistry was not determined.

Step-8:

[1077] To a stirred solution of rel-tert-butyl (2S,3S)-3-((tert-butyldiphenylsilyl)oxy)-2-(2,6- dichloropyridin-3-yl)piperidine-l -carboxylate (680 mg, 1.16 mmol) in THF (7 mL) was added TBAF (607 mg, 2.32 mmol) at room temperature under nitrogen atmosphere. The resulting mixture was stirred at room temperature for 2 h. The resulting mixture was concentrated under vacuum. The residue was purified by silica gel column chromatography, eluted with 0-50% EtOAc in PE to afford rel-tert-butyl (2S,3S)-2-(2,6-dichloropyridin-3-yl)- 3-hydroxypiperidine-l -carboxylate (255 mg, 99%) as a white solid. MS ESI calculated for C15H20CI2N2O3 [M+H]⁺, 347.09; found, 347.10. Absolute stereochemistry was not determined.

Step-9:

[1078] To a stirred solution of rel-tert-butyl (2S,3S)-2-(2,6-dichloropyridin-3-yl)-3- hydroxypiperidine-1 -carboxylate (220 mg, 0.63 mmol) in THF (5 mL) was added NaH (60% in mineral oil) (22 mg, 0.57 mmol) at 0 °C under nitrogen atmosphere. The resulting mixture was stirred at room temperature for 16 h. The reaction was quenched with ice water at room temperature. The resulting mixture was extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SO4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-30% EtOAc in PE to afford rel-tert-butyl (4aS,9bS)-7-chloro- 3,4,4a,9b-tetrahydrofuro[2,3-b:4,5-b']dipyridine-l(2H)-carboxylate (216 mg, 80%) as a colorless oil. MS ESI calculated for C15H19CIN2O3 [M+H]⁺, 311.11 ; found, 311.15. Absolute stereochemistry was not determined. Step- 10:

[1079] To a stirred solution of rel-tert-butyl (4aS,9bS)-7-chloro-3,4,4a,9b- tetrahydrofuro[2,3-b:4,5-b']dipyridine-l(2H)-carboxylate (252 mg, 0.81 mmol) and Zn(CN)2 (190 mg, 1.62 mmol) in DMF (3 mL) were added Zn powder (212 mg, 3.24 mmol), XPhos (38 mg, 0.08 mmol) and XPhos Pd G3 (68 mg, 0.08 mmol) at room temperature under nitrogen atmosphere. The resulting mixture was stirred at 130 °C for 16 h. The reaction was quenched by water and extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SO4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-30% EtOAc in PE to afford rel-tert-butyl (4aS,9bS)-7-cyano-3,4,4a,9b-tetrahydrofuro[2,3- b:4,5-b']dipyridine-l(2H)-carboxylate (156 mg, 99% yield) as a colorless oil. MS ESI calculated for C16H19N3O3 [M+H]⁺, 302.14 ; found, 302.20. Absolute stereochemistry was not determined.

Step-11:

A33

[1080] To a stirred solution of rel-tert-butyl (4aS,9bS)-7-cyano-3,4,4a,9b- tetrahydrofuro[2,3-b:4,5-b']dipyridine-l(2H)-carboxylate (126 mg, 0.41 mmol) in TFA (1 mL) and DCM (3 mL) at room temperature under nitrogen atmosphere. The resulting mixture was stirred at room temperature for 16 h under nitrogen atmosphere. The resulting mixture was concentrated under vacuum. The resulting residue was purified by reverse phase flash column chromatography with 5-50% acetonitrile in water (10 mM NH4HCO3) to afford rel- (4aS,9bS)-l,2,3,4,4a,9b-hexahydrofuro[2,3-b:4,5-b']dipyridine-7-carbonitrile (A33) (80.6 mg, 99% yield, 86% e.e.) as a white solid. MS ESI calculated for C11H11N3O [M+H]⁺, 202.09 ; found, 202.15. *H NMR (400 MHz, DMSO-</₆) 3 8.09 (d, J = 7.4 Hz, 1H), 7.76 (d, J = 7.4 Hz, 1H), 5.07 - 4.90 (m, 2H), 3.21 - 3.16 (m, 1H), 3.03 - 2.96 (m, 1H), 2.32 - 2.20 (m, 1H), 2.11 - 2.04 (m, 1H), 1.86 - 1.61 (m, 2H). Absolute stereochemistry was not determined.

Intermediate A34: (2R,4aS,10bS)-8-methoxy-2-methyl-l,2,3,4a,5,10b- hexahydropyrido[3',2':5,6]pyrano[3,4-b][l,4]oxazine hydrochloride

Step-1:

[1081] To a stirred mixture of 6-fluoro-5-iodopyridin-2-amine (50 g, 210.08 mmol) and H2SO4 (250 g, 255.10 mmol) in H2O (500 mL) was added a solution of NaNCh (28.98 g, 420.03 mmol) in H2O (100 mL) dropwise at -5 °C under nitrogen atmosphere. The mixture was allowed to warm at room temperature for 16 h with stirring. The precipitated solids were collected by filtration and washed with H2O. The solids were dried under vacuum to afford 6- fluoro-5-iodopyridin-2-ol (53 g, crude) as a light yellow solid that is used directly in next reaction. MS ESI calculated for C5H3FINO [M+l]⁺, 239.92; found, 239.90. 'H NMR (400 MHz, DMSO-rfe) 5 (ppm) 11.62 (s, 1H), 8.09 (dd, J = 9.2, 8.4 Hz, 1H), 6.45 (dd, J= 8.4, 1.6 Hz, 1H).

Step-2:

[1082] To a solution of 6-fluoro-5-iodopyridin-2-ol (53 g, 220.83 mmol) in DMF (530 mL) were added NaOH (17.74 g, 443.53 mmol) at room temperature. Then the mixture was stirred at 50 °C for 0.5 h. The reaction mixture was allowed to cool at room temperature. Then dimethyl sulfate (55.94 g, 443.53 mmol) was added dropwise to the reaction mixture at room temperature. The mixture was stirred at room temperature for 16 h. The reaction mixture was diluted by water and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered and concentrated under reduced pressure. The residue was purified by flash column chromatography with 0-10% ethyl acetate in petroleum ether to afford 2-fluoro-3-iodo-6-methoxypyridine (23.6 g, 42%) as a white solid. MS ESI calculated for C₆H₅FINO [M+l]⁺, 253.94; found, 253.95. 'H NMR (400 MHz, DMSO-rfe) 5 (ppm) 8.19 (t, J = 8.4 Hz, 1H), 6.66 (dd, J= 8.4, 1.6 Hz, 1H), 3.83 (s, 3H).

Step-3:

[1083] To a stirred mixture of 2-fluoro-3-iodo-6-methoxypyridine (23.6 g, 92.91 mmol), Pd(PPh₃)₂C12 (13.10 g, 18.65 mmol) and Cui (7.10 g, 37.31 mmol) in TEA (236 mL) was added tert-butyldimethyl(prop-2-yn-l-yloxy)silane (47.66 g, 279.82 mmol). The mixture was stirred at 100 °C under nitrogen atmosphere for 16 hours. The reaction mixture was diluted by water and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered and concentrated under reduced pressure. The residue was purified by flash column chromatography with 0-50% ethyl acetate in petroleum ether and further purified by reverse phase flash column chromatography with 5%~90% MeCN in water to afford 3-(3-((tert-butyldimethylsilyl)oxy)prop-l-yn-l-yl)-2- fluoro-6-methoxypyridine (20 g, 72%) as a brown oil. MS ESI calculated for CisHzzFNChSi [M+l]⁺, 296.14; found, 296.15. ¹H NMR (400 MHz, DMSO-J₆) 8 (ppm) 7.97 - 7.91 (m, 1H), 6.83 - 6.79 (m, 1H), 4.57 (s, 2H), 3.87 (s, 3H), 0.89 (s, 9H), 0.13 (s, 6H).

Step-4:

[1084] To a solution of 3-(3-((tert-butyldimethylsilyl)oxy)prop- 1 -yn- 1 -yl)-2-fluoro-6- methoxypyridine (20 g, 67.69 mmol) in THF (200 mL) was added TBAF (25.56 g, 101.54 mmol) at room temperature. The mixture was stirred at room temperature for 2 h. The mixture was concentrated under vacuum. The residue was purified by flash column chromatography with 0-100% ethyl acetate in petroleum ether to afford 3-(2-fluoro-6- methoxypyridin-3-yl)prop-2-yn-l-ol (13.6 g, 73%) as a light yellow solid. MS ESI calculated for C₉H₈FNO2 [M+l]⁺, 182.05; found, 182.15.

Step-5:

[1085] To a solution of 3-(2-fluoro-6-methoxypyridin-3-yl)prop-2-yn-l-ol (13.6 g, 74.72 mmol) in THF (136 mL) were added Lindlar catalyst (6.3 g, 59.17 mmol) and quinoline (9.56 g, 73.96 mmol) at room temperature. The mixture was stirred for 1 hour under hydrogen atmosphere (1 atm.). The mixture was filtered, the filtrate was concentrated under vacuum. The residue was diluted by water and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered and concentrated under reduced pressure. The residue was purified by flash column chromatography with 0-100% ethyl acetate in petroleum ether to afford (Z)-3-(2-fluoro-6- methoxypyridin-3-yl)prop-2-en-l-ol (22 g, crude) as a red oil. MS ESI calculated for C9H10FNO2 [M+l]⁺, 184.07; found, 184.05.

Step-6:

[1086] To a solution of (Z)-3-(2-fluoro-6-methoxypyridin-3-yl)prop-2-en-l-ol (22 g, 121.10 mmol) in DMF (800 mL) were added NaH (60% in mineral oil) (3.6 g, 90 mmol) at room temperature. The mixture was stirred at room temperature for 16 h. The reaction mixture was quenched by water and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered and concentrated under reduced pressure. The residue was purified by flash column chromatography with 0-80% ethyl acetate in petroleum ether to afford 7-methoxy-2H- pyrano[2,3-b]pyridine (5.39 g, 44%, over 2 steps) as a fight yellow oil. MS ESI calculated for C9H9NO2 [M+l]⁺, 164.06; found, 164.10. 'H NMR (400 MHz, DMSO-d₆) 3 (ppm) 7.39 (d, J = 8.0 Hz, 1H), 6.44 - 6.40 (m, 1H), 6.33 (d, J = 8.0 Hz, 1H), 5.71 - 5.67 (m, 1H), 4.98 - 4.96 (m, 2H), 3.76 (s, 3H).

[1087] A mixture of tert-butyl carbamate (11.79 g, 100.69 mmol) and NaOH (3.49 g, 87.69 mmol) in propan- l-ol (249 mL) and H2O (218 mL) was stirred at room temperature for 10 minutes. Then l,3-dichloro-5,5-dimethylimidazolidine-2, 4-dione (9.59 g, 48.72 mmol) was added to above mixture at room temperature. After stirring at room temperature for 30 minutes, (DHQD)2PHAL (supplier: Shanghai Accela ChemBio Co., Ltd. CAS# 140853-10-7) (2.51 g, 3.24 mmol), 7-methoxy-2H-pyrano[2,3-b]pyridine (5.30 g, 32.48 mmol) and Potassium osmate(VI) dihydrate (1.19 g, 3.24 mmol) were added to the mixture at 0 °C. The resulting mixture was allowed to warm at room temperature and stirred for 16 h. The reaction mixture was diluted by NaHCCh (sat.) and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered and concentrated under reduced pressure. The residue was purified by flash column chromatography with 0-15% ethyl acetate in petroleum ether to afford 3:1 mixture of tertbutyl ((3S,4S)-3-hydroxy-7-methoxy-3,4-dihydro-2H-pyrano[2,3-b]pyridin-4-yl)carbamate and tert-butyl ((3R,4R)-3-hydroxy-7-methoxy-3,4-dihydro-2H-pyrano[2,3-b]pyridin-4- yl)carbamate (1.31 g, 13%) as a white solid. MS ESI calculated for C14H20N2O5 [M+l]⁺, 297.14; found, 297.10. ¹H NMR (400 MHz, DMSO- ₆) 8 (ppm) 7.40 (d, J = 8.0 Hz, 1H), 6.69 (d, J = 9.2 Hz, 1H), 6.39 (d, J = 8.0 Hz, 1H), 5.28 (d, J = 4.0 Hz, 1H), 4.83 - 4.76 (m, 1H), 4.26 - 4.14 (m, 2H), 3.98 - 3.92 (m, 1H), 3.75 (s, 3H), 1.44 (s, 9H).

Step-8:

[1088] To a stirred 3:1 mixture of tert-butyl ((3S,4S)-3-hydroxy-7-methoxy-3,4-dihydro- 2H-pyrano[2,3-b]pyridin-4-yl)carbamate and tert-butyl ((3R,4R)-3-hydroxy-7-methoxy-3,4- dihydro-2H-pyrano[2,3-b]pyridin-4-yl)carbamate (1.3 g, 4.38 mmol) and NaOH (1.22 g, 30.71 mmol) in DCM (7.5 mL) were added (Bu4N)HSO4 (297 mg, 0.87 mmol) and (S)-4- methyl-l,3,2-dioxathiolane 2,2-dioxide (supplier: Suzhou spark Biotechnology Co., Ltd. CAS# 174953-30-1) (787 mg, 4.56 mmol) at 0 °C. The mixture was stirred at room temperature for 1 h. The resulting mixture was concentrated under reduced pressure. Then H2O (5 mL) and H2SO4 (8.6 g, 87.75 mmol) was added to the residue at room temperature. The resulting mixture was stirred at 80 °C for 16 h. The reaction mixture was basified with NaOH (aq.) and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered and concentrated under reduced pressure. The residue was dissolved in methanol (5 mL), then TEA (1.32 g, 13.14 mmol) and BOC2O (946 mg, 4.38 mmol) was added to the mixture at room temperature. The mixture was stirred at room temperature for 2 h. The resulting mixture was concentrated under reduced pressure. The residue was purified by flash column chromatography with 0-100% ethyl acetate in petroleum ether to afford 3:1 mixture of tert-butyl ((3S,4S)-3-((S)-2-hydroxypropoxy)-7- methoxy-3,4-dihydro-2H-pyrano[2,3-b]pyridin-4-yl)carbamate and tert-butyl ((3R,4R)-3- ((S)-2-hydroxypropoxy)-7-methoxy-3,4-dihydro-2H-pyrano[2,3-b]pyridin-4-yl)carbamate (1.12 g, 72%) as a white solid. MS ESI calculated for C17H26N2O6 [M+l]⁺, 355.18; found, 355.20.

Step-9:

[1089] To a solution of 3: 1 mixture of tert-butyl ((3S,4S)-3-((S)-2-hydroxypropoxy)-7- methoxy-3,4-dihydro-2H-pyrano[2,3-b]pyridin-4-yl)carbamate and tert-butyl ((3R,4R)-3- ((S)-2-hydroxypropoxy)-7-methoxy-3,4-dihydro-2H-pyrano[2,3-b]pyridin-4-yl)carbamate (1.12 g, 3.15 mmol) in toluene (10 mL) was added 2-(tributyl-X⁵- phosphaneylidene)acetonitrile (1.52 g, 6.30 mmol) at room temperature. The mixture was stirred at 110 °C for 16 h. The resulting mixture was concentrated under reduced pressure. The residue was purified by flash column chromatography with 0-100% ethyl acetate in petroleum ether to afford tert-butyl (2R,4aS,10bS)-8-methoxy-2-methyl-2,3,4a,10b- tetrahydropyrido[3',2':5,6]pyrano[3,4-b][l,4]oxazine-l(5H)-carboxylate (470 mg, 44%) as a light yellow semi-solid with longer retention time on flash column chromatography. MS ESI calculated for C17H24N2O5 [M+l]⁺, 337.17; found, 337.20.

[1090] The purification also afford tert-butyl (2R,4aR,10bR)-8-methoxy-2-methyl- 2,3,4a, 10b-tetrahydropyrido[3',2':5,6]pyrano[3,4-b][l ,4] oxazine- 1 (5H)-carboxylate (168 mg, 15%) as a brown oil with shorter retention time on flash column chromatography. MS ESI calculated for C17H24N2O5 [M+l]⁺, 337.17; found, 337.20.

Step- 10:

[1091] A mixture of tert-butyl (2R,4aS, 10bS)-8-methoxy-2-methyl-2,3,4a, 10b- tetrahydropyrido[3',2':5,6]pyrano[3,4-b][l,4]oxazine-l(5H)-carboxylate (470 mg, 1.39 mmol) and hydrogen chloride (gas, 4.0 M in ethyl acetate) (5 mL) was stirred at room temperature for 16 h. The mixture was concentrated under vacuum to afford (2R,4aS,10bS)-8-methoxy-2- methyl-l,2,3,4a,5,10b-hexahydropyrido[3',2':5,6]pyrano[3,4-b][l,4]oxazine hydrochloride (A34) (370 mg, crude) as a white solid. The stereochemistry was confirmed by NOE. MS ESI calculated for C12H16N2O3 [M+l]⁺, 237.12; found, 237.15. 'H NMR (400 MHz, Methanol-^) 5 (ppm) 7.86 (d, J = 8.4 Hz, 1H), 6.59 (d, J = 8.4 Hz, 1H), 4.81 - 4.68 (m, 2H), 4.58 - 4.52 (m, 1H), 4.44 - 4.39 (m, 1H), 4.01 - 3.91 (m, 1H), 3.90 (s, 3H), 3.77 - 3.62 (m, 2H), 1.38 - 1.26 (m, 3H).

Intermediate A35: (2R,4aS, 10bS)-8-(difluoromethoxy)-2-methyl- 1 ,2, 3, 4a, 5, 10b- hexahydropyrido[3',2':5,6]pyrano[3,4-b][l,4]oxazine Step-1:

[1092] To a stirred solution of H2SO4 (0.84 M) (1.25 L) was added 6-fluoro-5-iodopyridin- 2-amine (50.00 g, 210.08 mmol) at -5 °C under nitrogen atmosphere. The mixture was stirred at -5 °C for 10 min. A solution of NaNCh (28.99 g, 420.16 mmol) in H2O (250 mL) was added dropwise at -5 °C. The resulting mixture was stirred at -5 °C for 2 h. The precipitated solids were collected by filtration and washed with H2O. The solids were dried under reduced pressure to afford 6-fluoro-5-iodopyridin-2-ol (46.9 g, 93% yield) as a brown solid. MS ESI calculated for (C5H3FINO) [M+H]⁺, 239.92; found, 239.90.

Step-2:

[1093] To a stirred solution of 6-fluoro-5-iodopyridin-2-ol (46.90 g, 196.24 mmol) in DCM (500 mL) was added a solution of KOH (66.06 g, 1177.46 mmol) in H2O (264 mL) dropwise at 0 °C. Then (bromodifluoromethyl)trimethylsilane (79.72 g, 392.49 mmol) was added dropwise to above mixture at 0 °C. The resulting mixture was stirred at room temperature for 16 h. The reaction mixture was quenched by the addition of water and extracted with dichloromethane. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under vacuum. The resulting residue was purified by flash column chromatography with a 330 g silica gel column and eluted with 0-8% ethyl acetate in petroleum ether to afford 6-(difluoromethoxy)-2-fluoro-3-iodopyridine (28.3 g, 49% yield) as a yellow oil. MS ESI calculated for C6H3F3INO [M+H]⁺, 289.92; found, 290.00. 'H NMR (400 MHz, DMSO-rf₆) 3 8.45 - 8.42 (m, 1H), 7.76 - 7.40 (m, 1H), 6.92 (dd, 7= 8.2, 1.2 Hz, 1H).

Step-3:

[1094] To a stirred solution of 6-(difluoromethoxy)-2-fluoro-3-iodopyridine (28.30 g, 97.93 mmol) and tert-butyldimethyl(prop-2-yn-l-yloxy)silane (50.04 g, 293.78 mmol) in Et₃N (300 mL) were added Pd(PPh₃)₂C12 (13.75 g, 19.59 mmol) and Cui (7.46 g, 39.17 mmol) at room temperature under nitrogen atmosphere. The resulting mixture was stirred at 100 °C for 16 h. The reaction mixture was quenched by the addition of water and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under vacuum. The resulting residue was purified by normal phase flash column chromatography with a 330 g silica gel column and eluted with 0-8% ethyl acetate in petroleum ether to afford 3-(3-((tert- butyldimethylsilyl)oxy)prop-l-yn-l-yl)-6-(difluoromethoxy)-2-fluoropyridine (37.9 g, 70% yield) as a brown oil. MS ESI calculated for CisFhoFsNChSi [M+H]⁺, 332.12; found, 332.15.

Step-4:

[1095] To a stirred solution of 3-(3-((tert-butyldimethylsilyl)oxy)prop-l-yn-l-yl)-6- (difhjoromethoxy)-2-fluoropyridine (32.90 g, 99.27 mmol) in THF (350 mL) was added HC1 (aq., IM) (35 mL) at room temperature. The resulting mixture was stirred at room temperature for 2 h. The reaction mixture was quenched by the addition of water and extracted with ethyl acetate. The combined organic layers were washed with NaHCO₃ (sat.) and brine. The organic layers were dried over anhydrous sodium sulfate, filtered, and concentrated under vacuum. The resulting residue was purified by normal phase flash column chromatography with a 330 g silica gel column and eluted with 0-30% ethyl acetate in petroleum ether to afford 3-(6-(difluoromethoxy)-2-fluoropyridin-3-yl)prop-2-yn-l-ol (11.5 g, 53% yield) as a brown oil. MS ESI calculated for C9H6F3NO2 [M+H]⁺, 218.04; found, 218.00.

Step-5:

[1096] To a solution of 3-(6-(difluoromethoxy)-2-fluoropyridin-3-yl)prop-2-yn-l -ol (11.50 g, 52.96 mmol) in i-PrOH (350 mL) was added Lindlar catalyst (2.30 g, 4.77 mmol) at room temperature. The mixture was placed under hydrogen atmosphere with a balloon (1 atm.). The reaction mixture was degassed via vacuum evacuation, then backfilled with hydrogen, and this process was repeated three times. The reaction mixture was stirred at room temperature for 2 h under hydrogen atmosphere. The resulting mixture was filtered, the filter cake was washed with ethyl acetate. The filtrate was concentrated under reduced pressure to afford (Z)-3-(6-(difhioromethoxy)-2-fluoropyridin-3-yl)prop-2-en-l-ol (11.5 g, crude) as a brown oil, which was used in next reaction directly. MS ESI calculated for C9H8F3NO2 [M+H]⁺, 220.05; found, 220.05. 'H NMR (400 MHz, DMSO- ₆) 8 7.96 (dd, J = 10.0, 8.0 Hz, 1H), 7.62 (t, J = 72.0 Hz, 1H), 7.08 (dd, J= 8.0, 0.8 Hz, 1H), 6.30 - 6.32 (m, 1H), 6.05 - 5.97 (m, 1H), 4.98 - 4.95 (m, 1H), 4.26 - 4.01 (m, 2H).

Step-6:

[1097] To a stirred solution of (Z)-3-(6-(difluoromethoxy)-2-fluoropyridin-3-yl)prop-2-en- l-ol (11.50 g, 52.47 mmol) in DMF (150 mL) was added CS2CO3 (25.64 g, 78.71 mmol) at room temperature. The resulting mixture was stirred at 60 °C for 2 h. The reaction mixture was quenched by the addition of water and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under vacuum. The resulting residue was purified by normal phase flash column chromatography with a 120 g silica gel column and eluted with 0-8% ethyl acetate in petroleum ether to afford 7-(difluoromethoxy)-2H-pyrano[2,3-b]pyridine (3.8 g, 36% yield) as a light yellow oil. MS ESI calculated for C9H7F2NO2 [M+H]⁺, 200.04; found, 200.05. ¹H NMR (400 MHz, DMSO-d₆) 8 7.81 - 7.22 (m, 2H), 6.57 (d, J = 7.6 Hz, 1H), 6.50 - 6.47 (m, 1H), 5.85 - 5.81 (m, 1H), 5.06 (dd, J= 3.4, 2.0 Hz, 2H).

Step-7:

[1098] To a stirred solution of tert-butyl carbamate (7.48 g, 63.82 mmol) in propan- l-ol (80 mL) was added a solution of NaOH (2.22 g, 55.59 mmol) in H2O (70 mL) at room temperature. The mixture was stirred at room temperature for 10 minutes, then 1,3-dichloro- 5, 5-dimethylimidazolidine-2, 4-dione (6.08 g, 30.88 mmol) was added at room temperature. After stirring at room temperature for 30 minutes, a solution of (DHQD)2PHAL (1.60 g, 2.06 mmol) (supplier: ShangHai Accela ChemBio Co., Ltd. CAS# 140853-10-7) in propan-l-ol (21 mL) and a solution of 7-(difluoromethoxy)-2H-pyrano[2,3-b]pyridine (4.10 g, 20.59 mmol) in propan-l-ol (9 mL) were added dropwise at 0 °C. This was followed by the addition of Potassium osmate(VI) dihydrate (759 mg, 2.06 mmol). The resulting mixture was stirred at room temperature for 16 h. The reaction mixture was quenched by the addition of brine and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under vacuum. The resulting residue was purified by normal phase flash column chromatography and eluted with 0-50% ethyl acetate in petroleum ether to afford a 5:1 mixture of tert-butyl ((3S,4S)-7- (difluoromethoxy)-3-hydroxy-3,4-dihydro-2H-pyrano[2,3-b]pyridin-4-yl)carbamate and tertbutyl ((3R,4R)-7-(difluoromethoxy)-3-hydroxy-3,4-dihydro-2H-pyrano[2,3-b]pyridin-4- yl)carbamate (1.27 g, 19% yield) as a white solid. MS ESI calculated for C14H18F2N2O5 [M+H]⁺, 333.12; found, 333.20. 'H NMR (400 MHz, DMSO- ₆) 5 7.84 - 7.32 (m, 2H), 6.83 (d, J= 9.2 Hz, 1H), 6.63 (d, J= 8.0 Hz, 1H), 5.39 (br, 1H), 4.86 (dd, J = 9.6, 3.6 Hz, 1H), 4.34 (d, J = 11.6 Hz, 1H), 4.23 (dd, J= 11.2, 4.4 Hz, 1H), 4.01 - 4.00 (m, 1H), 1.45 (s, 9H).

Step-8:

[1099] To a stirred solution of 5:1 mixture of tert-butyl ((3S,4S)-7-(difluoromethoxy)-3- hydroxy-3,4-dihydro-2H-pyrano[2,3-b]pyridin-4-yl)carbamate and tert-butyl ((3R,4R)-7- (difluoromethoxy)-3-hydroxy-3,4-dihydro-2H-pyrano[2,3-b]pyridin-4-yl)carbamate ( 1.07 g, 3.22 mmol) in DCM (20 mL) were added Tetrabutylammonium sulfate (50 wt.% in H2O) (374 mg, 0.64 mmol), NaOH (901 mg, 22.54 mmol) and (4S)-4-m ethyl- 1,3,2- X-6- dioxathiolane-2, 2-dione (supplier: Suzhou spark Biotechnology Co., Ltd. CAS# 174953-30- 1) (578 mg, 4.19 mmol) at room temperature. The mixture was stirred at room temperature for 16 h. The mixture was concentrated under vacuum. The residue was acidified to pH 7 with HC1 (aq., IM). The resulting mixture was extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous NaiSCL. After filtration, the filtrate was concentrated under reduced pressure. The residue was dissolved in THF (10 mL), Citric acid (653 mg, 3.40 mmol) was added at room temperature. The resulting mixture was stirred at room temperature for 16 h. The reaction was quenched with water. The mixture was basified with NaHCCL (sat.) to pH 7. The resulting mixture was extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous NazSO4. After filtration, the filtrate was concentrated under reduced pressure. The resulting residue was purified by normal phase flash column chromatography and eluted with 0-50% ethyl acetate in petroleum ether to afford a 5:1 mixture of tert-butyl ((3S,4S)-7-(difluoromethoxy)-3-((S)-2- hydroxypropoxy)-3,4-dihydro-2H-pyrano[2,3-b]pyridin-4-yl)carbamate and tert-butyl ((3R,4R)-7-(difhioromethoxy)-3-((S)-2-hydroxypropoxy)-3,4-dihydro-2H-pyrano[2,3- b]pyridin-4-yl)carbamate (527 mg, 64% yield) as a white solid. MS ESI calculated for C17H24F2N2O6 [M+H]⁺, 391.16; found, 391.20.

Step-9:

[1100] To a stirred solution of a 5:1 mixture of tert-butyl ((3S,4S)-7-(difluoromethoxy)-3- ((S)-2-hydroxypropoxy)-3,4-dihydro-2H-pyrano[2,3-b]pyridin-4-yl)carbamate and tert-butyl ((3R,4R)-7-(difhioromethoxy)-3-((S)-2-hydroxypropoxy)-3,4-dihydro-2H-pyrano[2,3- b]pyridin-4-yl)carbamate (527 mg, 1.35 mmol) in toluene (6 mL) was added 2-(tributyl-A,⁵- phosphaneylidene)acetonitrile (CAS No. 157141-27-0) (651 mg, 2.70 mmol) at room temperature under nitrogen atmosphere. The resulting mixture was stirred at 110 °C for 16 h. The resulting mixture was concentrated under vacuum. The resulting residue was purified by normal phase flash column chromatography and eluted with 0-25% ethyl acetate in petroleum ether to afford tert-butyl (2R,4aS,10bS)-8-(difluoromethoxy)-2-methyl-2,3,4a,10b- tetrahydropyrido[3',2':5,6]pyrano[3,4-b][l,4]oxazine-l(5H)-carboxylate (378 mg, 75% yield) as a light yellow solid. The stereochemistry was confirmed by NOE. MS ESI calculated for C17H22F2N2O5 [M+H]⁺, 373.15; found, 373.15. NMR (400 MHz, DMSO-d6) 5 7.83 - 7.36 (m, 2H), 6.72 - 6.66 (m, 1H), 5.28 - 5.19 (m, 1H), 4.53 - 4.36 (m, 2H), 4.04 - 3.90 (m, 1H), 3.84 - 3.83 (m, 1H), 3.78 - 3.59 (m, 2H), 1.50 (s, 9H), 0.71 - 0.66 (m, 3H).

[1101] The column purification also afford a 3:2 mixture of tert-butyl (2R,4aR,10bR)-8- (difhioromethoxy)-2-methyl-2,3 ,4a, 10b-tetrahydropyrido[3 ',2' :5 ,6]pyrano [ ,4-b] [ 1 ,4] oxazine- l(5H)-carboxylate and tert-butyl (2R,4aS,10bS)-8-(difhioromethoxy)-2-methyl-2,3,4a,10b- tetrahydropyrido[3',2':5,6]pyrano[3,4-b][l,4]oxazine-l(5H)-carboxylate (160 mg) as a yellow oil.

Step-10: [1102] To a stirred solution of tert-butyl (2R,4aS,10bS)-8-(difluoromethoxy)-2-methyl- 2,3 ,4a, 1 Ob-tetrahydropyrido[3 ',2' :5 ,6]pyrano [3 ,4-b] [ 1 ,4] oxazine- 1 (5H)-carboxylate (378 mg, 1.02 mmol) in ethyl acetate (3 mL) was added hydrogen chloride (4.0 M in ethyl acetate) (1 mL) at room temperature. The resulting mixture was stirred at room temperature for 1 h. The resulting mixture was concentrated under vacuum to afford (2R,4aS,10bS)-8- (difluoromethoxy)-2-methyl-l,2,3,4a,5,10b-hexahydropyrido[3^,,2':5,6]pyrano[3,4- b][ 1,4] oxazine hydrochloride (A35) (290 mg, 92% yield) as a light yellow solid. MS ESI calculated for C12H14F2N2O3 [M+H]⁺, 273.10; found, 273.10. 'H NMR (400 MHz, DMSO- rf₆) 8 10.91 (s, 1H), 9.77 (s, 1H), 8.31 (d, 7 = 8.0 Hz, 1H), 7.62 (t, 7 = 72.0 Hz, 1H), 6.83 (d, 7 = 8.4 Hz, 1H), 5.04 - 4.85 (m, 1H), 4.68 - 4.67 (m, 1H), 4.56 - 4.42 (m, 1H), 4.36 - 4.22 (m, 1H), 3.87 (dd, 7 = 12.0, 3.2 Hz, 1H), 3.67- 3.40 (m, 2H), 1.19 (d, 7= 6.4 Hz, 3H).

Intermediate A38: (2R,4aR, 10bS)-2-methyl-8-(trifluoromethyl)-2,3,4a,5,6, lOb-hexahydro- 1 H- [ 1 ,4] oxazino [3 ,2-f]quinoline

Step-1:

[1103] To a stirred solution of 3-aminocyclohex-2-en- 1-one (100.00 g, 899.73 mmol) and (E)-4-ethoxy-l,l,l-trifluorobut-3-en-2-one (302.52 g, 1799.47 mmol) in MeCN (1000 mL) were added FeCh (14.59 g, 89.97 mmol) and pyrrolidine hydrochloride (48.40 g, 449.87 mmol) at room temperature. The resulting mixture was stirred at 60 °C for 8 h under nitrogen atmosphere. The solvent was removed under reduced pressure. The residue was diluted by water and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered and concentrated under vacuum. The residue was purified by flash column chromatography with 0-30% ethyl acetate in petroleum ether to afford 2-(trifluoromethyl)-7,8-dihydroquinolin-5(6H)-one (20.60 g, 11%) as a brown oil. MS ESI calculated for CioHsFsNO [M+H]⁺, 216.06; found, 216.10.

Step-2:

[1104] To a stirred solution of 2-(trifluoromethyl)-7,8-dihydroquinolin-5(6H)-one (20.60 g, 95.74 mmol) in methanol (300 mL) was added NaBFU (7.24 g, 191.47 mmol) in portions at 0 °C. The resulting mixture was stirred at room temperature for 1 h. The reaction mixture was quenched by water at 0 °C. The MeOH was removed under vacuum, the aqueous solution was extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate and concentrated under vacuum. The residue was purified by flash column chromatography with 0-50% ethyl acetate in petroleum ether to afford a 1:1 mixture of (S)-2-(trifluoromethyl)-5,6,7,8-tetrahydroquinolin-5-ol and (R)-2- (trifluoromethyl)-5,6,7,8-tetrahydroquinolin-5-ol (10.80 g, 52%) as a colorless oil. MS ESI calculated for C10H10F3NO [M+l]⁺, 218.07; found, 218.15.

Step-3:

[1105] A solution of a 1:1 mixture of (S)-2-(trifluoromethyl)-5,6,7,8-tetrahydroquinolin-5- ol and (R)-2-(trifluoromethyl)-5,6,7,8-tetrahydroquinolin-5-ol (10.80 g, 49.73 mmol) in PPA (100 mL) was stirred at 110 °C for 4 h. The residue was diluted by water and basified to pH 8 with NH3-H2O (aq.). The resulting mixture was extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered and concentrated under vacuum. The residue was purified by flash column chromatography with 0-70% ethyl acetate in petroleum ether to afford 2-(trifluoromethyl)-7,8-dihydroquinoline (7.10 g, 72%) as a colorless oil. MS ESI calculated for C10H8F3N [M+H]⁺, 200.06; found, 200.10.

Step-4:

[1106] To a solution of tert-butyl carbamate (12.35 g, 105.44 mmol) in propan- l-ol (260 mL) were sequentially added NaOH (aq., 0.4 M) (260 rnL) and tert-butyl hypochlorite (11.45 g, 105.44 mmol). The resulting mixture was stirred at room temperature for 30 min. Then a solution of (DHQD)2PHAL (supplier: ShangHai Accela ChemBio Co., Ltd. CAS# 140853- 10-7) (2.74 g, 3.52 mmol) in propan- l-ol (40 mL) was added to above mixture at 0 oC. After stirring at 0 °C for 30 min. 2-(trifhioromethyl)-7,8-dihydroquinoline (7.00 g, 35.15 mmol) and Potassium osmate (VI) dihydrate (1.29 g, 3.56 mmol) were added to above mixture at 0 °C. The resulting mixture was stirred at room temperature for 16 h. The resulting mixture was diluted with water. The resulting mixture was extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by reverse phase flash with 5-50% acetonitrile in water to afford a 2:1 mixture of tert-butyl ((5S,6R)-6- hydroxy-2-(trifhioromethyl)-5,6,7,8-tetrahydroquinolin-5-yl)carbamate and tert-butyl ((5R,6S)-6-hydroxy-2-(trifluoromethyl)-5,6,7,8-tetrahydroquinolin-5-yl)carbamate (1.90 g, 16%) as a yellow oil. MS (ESI) calculated for C15H19F3N2O3 [M+H]⁺, 333.13; found, 333.20.

Step-5:

[1107] To a solution of a 2:1 mixture of tert-butyl ((5S,6R)-6-hydroxy-2-(trifluoromethyl)- 5,6,7,8-tetrahydroquinolin-5-yl)carbamate and tert-butyl ((5R,6S)-6-hydroxy-2-

(trifhioromethyl)-5,6,7,8-tetrahydroquinolin-5-yl)carbamate (1.90 g, 5.72 mmol) in DCM (30 mL) were added (Bu₄N)HSO4 (0.39 g, 1.14 mmol), NaOH (1.60 g, 40.02 mmol) and (4S)-4-methyl-l, 3, 2-X-6-dioxathiolane-2, 2-dione (supplier: Suzhou spark Biotechnology Co., Ltd. CAS# 174953-30-1) (1.03 g, 7.43 mmol) at 0 °C with stirring. The resulting mixture was stirred at room temperature for 2 h. Then H2O (20 mL) and H2SO4 (1.32 g, 13.50 mmol) were added to the reaction mixture at 0 °C. The resulting mixture was stirred at 80 °C for 16 h. Then the mixture was diluted with water and basified by NaOH (aq., 30%) to pH 8. The resulting mixture was extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate. After filtration, the filtrate was concentrated under reduced pressure to afford a 2:1 mixture of (S)-l-(((5S,6R)-5-amino-2- (trifluoromethyl)-5,6,7,8-tetrahydroquinolin-6-yl)oxy)propan-2-ol and (S)- 1 -(((5R,6S)-5- amino-2-(trifluoromethyl)-5,6,7,8-tetrahydroquinolin-6-yl)oxy)propan-2-ol (2.10 g, crude) as a yellow oil. MS ESI calculated for C13H17F3N2O2 [M+H]⁺, 291.12; found, 291.10.

Step-6:

[1108] To a solution of a 2:1 mixture of (S)-l-(((5S,6R)-5-amino-2-(trifluoromethyl)- 5,6,7,8-tetrahydroquinolin-6-yl)oxy)propan-2-ol and (S)- 1 -(((5R,6S)-5-amino-2- (trifluoromethyl)-5,6,7,8-tetrahydroquinolin-6-yl)oxy)propan-2-ol (1.90 g, 6.54 mmol), TEA (1.99 g, 19.64 mmol) in MeOH (20 mL) was added BOC2O (1.43 g, 6.54 mmol). The resulting mixture was stirred at room temperature for 2 h. The solvent was concentrated under vacuum. The residue was purified by flash column chromatography with 0-50% ethyl acetate in petroleum ether to afford a 2: 1 mixture of tert-butyl ((5S,6R)-6-((S)-2-hydroxypropoxy)-2- (trifluoromethyl)-5,6,7,8-tetrahydroquinolin-5-yl)carbamate and tert-butyl ((5R,6S)-6-((S)-2- hydroxypropoxy)-2-(trifluoromethyl)-5,6,7,8-tetrahydroquinolin-5-yl)carbamate (1.50 g, 59%) as an off-white solid. MS ESI calculated for C18H25F3N2O4 [M4-H]⁺, 391.18; found, 391.15.

Step-7: [1109] To a solution of a 2:1 mixture of tert-butyl ((5S,6R)-6-((S)-2-hydroxypropoxy)-2- (trifluoromethyl)-5,6,7,8-tetrahydroquinolin-5-yl)carbamate and tert-butyl ((5R,6S)-6-((S)-2- hydroxypropoxy)-2-(trifluoromethyl)-5,6,7,8-tetrahydroquinolin-5-yl)carbamate (1.60 g, 4.09 mmol) in toluene (20 mL) was added 2-(tributyl-X⁵-phosphaneylidene)acetonitrile (CAS No. 157141-27-0) (1.98 g, 8.19 mmol) at room temperature. The resulting mixture was stirred at 110 °C for 5 h. The solvent was removed under vacuum. The residue was purified by flash column chromatography with 0-40% ethyl acetate in petroleum ether to afford a 2:1 mixture of tert-butyl (2R,4aR,10bS)-2-methyl-8-(trifluoromethyl)-2,3,4a,5,6,10b-hexahydro-lH- [l,4]oxazino[3,2-f]quinoline-l-carboxylate and tert-butyl (2R,4aS,10bR)-2-methyl-8- (trifluoromethyl)-2,3,4a,5 ,6, 1 Ob-hexahydro- 1 H- [ 1 ,4] oxazino [3 ,2-f]quinoline- 1 -carboxylate (1.20 g, 78%) as a yellow oil. MS ESI calculated for C18H23F3N2O3 [M+H]⁺, 373.17; found, 373.20.

Step-8:

A38

[1110] A 2:1 mixture of tert-butyl (2R,4aR,10bS)-2-methyl-8-(trifluoromethyl)-

2,3 ,4a, 5 ,6,1 Ob-hexahydro- 1H- [ 1 ,4] oxazino[3,2-f] quinoline- 1 -carboxylate and tert-butyl (2R,4aS,10bR)-2-methyl-8-(trifluoromethyl)-2,3,4a,5,6,10b-hexahydro-lH-[l,4]oxazino[3,2- f]quinoline-l -carboxylate (1.2 g, 3.22 mmol) and HC1 (4M in 1,4-dioxane) (10 mL) was stirred at room temperature for 1 h. The resulting mixture was concentrated under vacuum. The crude product (1100 mg) was separated by Prep-chiral-HPLC with the following conditions (Column: CHIRAL ART Cellulose-SC, 2*25 cm, 5 pm; Mobile Phase A: Hex (0.5% 2M NH3-MeOH), Mobile Phase B: MEOH: DCM=1: 4-HPLC; Flow rate: 20 mL/min; Gradient (B%): 7% B to 7% B in 9 min; Wave Length: 220/254 nm; RTl(min): 6.28; RT2(min): 7.76; Sample Solvent: MeOH: EtOH=l: 1— HPLC; Injection Volume: 0.26 mL; Number Of Runs: 25) to afford (2R,4aS,10bR)-2-methyl-8-(trifluoromethyl)- 2,3,4a,5,6,10b-hexahydro-lH-[l,4]oxazino[3,2-f]quinoline (220 mg, 30%) as a white solid as the first eluting peak. The stereochemistry was confirmed by NOE. MS ESI calculated for Ci3H₁₅F3N2O [M+H]⁺, 273.11; found, 273.05. 'H NMR (300 MHZ, DMSO-J₆) 8 8.38 (d, J = 8.0 Hz, 1H), 7.73 (d, J= 8.0 Hz, 1H), 4.07 - 3.85 (m, 2H), 3.65 - 3.60 (m, 1H), 3.18 - 3.11 (m, 1H), 3.05 - 2.90 (m, 1H), 2.85 - 2.72 (m, 1H), 2.47 - 2.35 (m, 1H), 2.18 - 1.90 (m, 2H), 0.87 (d, 7 = 6.4 Hz, 3H).

[1111] The chiral resolution also afford (2R,4aR,10bS)-2-methyl-8-(trifluoromethyl)- 2,3,4a,5,6,10b-hexahydro-lH-[l,4]oxazino[3,2-f]quinoline (A38) (400 mg, 55%) as a white solid as the second eluting peak. The stereochemistry was confirmed by NOE. MS ESI calculated for C13H15F3N2O [M+H]⁺, 273.11; found, 273.05. ¹H NMR (300 MHz, DMSO- fe) 5 8.38 (d, J= 8.0 Hz, 1H), 7.73 (d, J= 8.0 Hz, 1H), 4.07 - 3.85 (m, 2H), 3.65 - 3.60 (m, 1H), 3.18 - 3.11 (m, 1H), 3.05 - 2.90 (m, 1H), 2.85 - 2.72 (m, 1H), 2.47 - 2.35 (m, 1H), 2.18 - 1.90 (m, 2H), 0.87 (d, J = 6.4 Hz, 3H).

Intermediate A39: 1:1 mixture of rel-(3R,4aS,9bS)-7-(difhioromethoxy)-3-fluoro- l,2,3,4,4a,9b-hexahydrobenzofuro[3,2-b]pyridine isomer 1 and rel-(3R,4aS,9bS)-7- (difluoromethoxy)-3-fluoro-l,2,3,4,4a,9b-hexahydrobenzofuro[3,2-b]pyridine isomer 2

[1112] To a stirred solution of 4-chloro-2-hydroxyphenylboronic acid (10.00 g, 58.01 mmol) and K2CO3 (24.05 g, 174.04 mmol) in 1,4-dioxane (150 mL) were added 2-bromo- 3,5-difluoropyridine (12.38 g, 63.81 mmol) and Pd(dppf)C12-CH2C12 (4.74 g, 5.80 mmol) at 25°C. The resulting mixture was stirred at 90°C for 2 h under nitrogen atmosphere. The resulting mixture was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-25% EtOAc in petroleum ether to afford 5-chloro- 2-(3,5-difluoropyridin-2-yl)phenol (13.5 g, 96% yield) as a white solid. MS (ESI) calculated for (C11H6CIF2NO) [M+H]⁺, 242.01; found, 242.00.

Step-2:

[1113] To a stirred solution of 5-chloro-2-(3,5-difluoropyridin-2-yl)phenol (13.50 g, 55.87 mmol) in DMF (140 mL) were added K2CO3 (15.44 g, 111.74 mmol) at 30 °C. The resulting mixture was stirred at 120 °C for 3 h. The resulting mixture was diluted by water and extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous NaiSt After filtration, the filtrate was concentrated under reduced pressure to afford 7-chloro-3-fluorobenzofuro[3,2-b]pyridine (10.8 g, 87% yield) as a white solid. MS (ESI) calculated for (C11H5CIFNO) [M+H]⁺, 222.00; found, 221.95.

Step-3:

[1114] To a stirred solution of 7-chloro-3-fluorobenzofuro[3,2-b]pyridine (9.25 g, 41.73 mmol) and Herrmann's catalyst (1.96 g, 2.08 mmol) in DMF (504 mL) and H2O (56 mL) were added t-BuXPhos (3.54 g, 8.34 mmol) and K2CO3 (44.99 g, 325.55 mmol) at 30 °C. The resulting mixture was stirred at 120°C for 2 h under nitrogen atmosphere. The mixture was quenched by water and acidified with HC1 (aq.) to pH 3. The resulting mixture was extracted with EtOAc. The combined organic layers were washed with brine, then dried over anhydrous Na2SO4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-50% EtOAc in petroleum ether to afford 3-fluorobenzofuro[3,2-b]pyridin-7-ol (5.6 g, 66% yield) as a white solid. MS (ESI) calculated for (Ci iHeFNCh) [M+H]⁺, 204.04; found, 204.05.

Step-4:

[1115] To a stirred solution of 3-fluorobenzofuro[3,2-b]pyridin-7-ol (35.00 g, 172.26 mmol) in DMF (350 mL) were added sodium 2-chloro-2,2-difhioroacetate (31.52 g, 206.72 mmol) and K2CO3 (47.62 g, 344.53 mmol) at 30 °C. The resulting mixture was stirred at 90 °C for 3 h. The mixture was cooled and diluted by water. The resulting mixture was extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SO4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-50% EtOAc in PE to afford 7-(difluoromethoxy)-3-fluorobenzofuro[3,2-b]pyridine (11.00 g, 25% yield) as an off-white solid. MS (ESI) calculated for (C12H6F3NO2) [M+H]⁺, 254.04; found, 254.05.

Step-5:

A39

[1116] To a stirred solution of 7-(difluoromethoxy)-3-fluorobenzofuro[3,2-b]pyridine (6.40 g, 25.27 mmol) in THF (60 mL) were added HC1 (cone.) (2.21 g, 60.667 mmol) and Palladium hydroxide (Pd 20% on carbon powder, nominally 50% water) (2.55 g) in portions at 30 °C. The resulting mixture was stirred at 70 °C for 16 h under hydrogen atmosphere (50 atm.). The resulting mixture was filtered, the filter cake was washed with mixture of MeOH and water. The filtrate was concentrated under reduced pressure. The residue was dissolved in H2O (60 mL). The mixture was acidified with HC1 (aq.) to pH 4. The resulting mixture was extracted with EtOAc. The water layers were collected and basified NaHCCh (sat.) to pH 8. The mixture was extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SO4. After filtration, the filtrate was concentrated under reduced pressure. The crude product was purified by Prep-HPLC with the following conditions (Column: YMC-Actus Triart C18 ExRS, 20*250 mm, 5pm; Mobile Phase A: Water (10 mmol/L NH3HCO3), Mobile Phase B: ACN; Flow rate: 20 mL/min; Gradient: 35% B to 50% B in 10 min; Wave Length: 253/220 nm) to afford a 1:1 mixture of rel- (3R,4aS ,9bS)-7 -(difluoromethoxy)-3-fluoro- 1 ,2,3 ,4,4a, 9b-hexahydrobenzofuro [3 ,2- b]pyridine isomer 1 and (3R,4aS,9bS)-7-(difluoromethoxy)-3-fluoro-l,2,3,4,4a,9b- hexahydrobenzofuro[3,2-b]pyridine isomer 2 (A39) (160 mg, 2% yield) as a white solid. MS (ESI) calculated for (C12H12F3NO2) [M+H]⁺, 260.08; found, 260.10. 'H NMR (400 MHz, DMSO- ₆) 87.33 (d, J= 7.8 Hz, 1H), 7.20 (t, J = 74.4 Hz, 1H), 6.73 - 6.63 (m, 2H), 4.81 - 4.62 (m, 1H), 4.66 - 4.57 (m, 1H), 4.29 (d, J = 6.4 Hz, 1H), 2.94 - 2.84 (m, 1H), 2.72 - 2.57 (m, 1H), 2.39 - 1.97 (m, 3H). The relative stereochemistry is arbitrarily assigned.

Intermediate A39 isomer 1: rel-(3R,4aS,9bS)-7-(difluoromethoxy)-3-fluoro-l,2,3,4,4a,9b- hexahydrobenzofuro[3,2-b]pyridine, isomer 1 A39, Isomer

Intermediate A39 isomer 2: rel-(3R,4aS,9bS)-7-(difluoromethoxy)-3-fluoro-l,2,3,4,4a,9b- hexahydrobenzofuro[3,2-b]pyridine, isomer 2

A39, Isomer 2

[1117] The racemic mixture (2.8 g) was separated by Prep-Chiral SFC with the following conditions (Column: CHIRALPAK IG, 3*25 cm, 10 pm; Mobile Phase A: CO2, Mobile Phase B: MeOH: ACN=1: 1; Flow rate: 100 mL/min; Gradient: isocratic 30% B; Wave Length: 220 nm; RTl(min): 2.5; RT2(min): 4.5; Sample Solvent: MEOH) to afford rel- (3R,4aS ,9bS)-7 -(difhioromethoxy)-3-fluoro- 1 ,2,3 ,4,4a, 9b-hexahydrobenzofuro [3 ,2- b]pyridine, isomer 2 (A39 isomer 2) (840 mg, 30% yield) as a white solid with the first peak on SFC. MS (ESI) calculated for (C12H12F3NO2) [M+H]⁺, 260.08; found, 260.10. 'H NMR (400 MHz, DMSO-d₆) 6 7.33 (d, J= 7.8 Hz, 1H), 7.20 (t, J = 74.4 Hz, 1H), 6.73 - 6.63 (m, 2H), 4.81 - 4.62 (m, 1H), 4.66 - 4.57 (m, 1H), 4.29 (d, J = 6.4 Hz, 1H), 2.94 - 2.84 (m, 1H), 2.72 - 2.57 (m, 1H), 2.39 - 1.97 (m, 3H). The relative and absolute stereochemistry for A39 isomer 2 is arbitrarily assigned.

[1118] The above chiral resolution also afford rel-(3R,4aS,9bS)-7-(difluoromethoxy)-3- fluoro-l,2,3,4,4a,9b-hexahydrobenzofuro[3,2-b]pyridine, isomer 1 (A39 isomer 1) (860 mg, 30% yield) as a colorless oil with the second peak on SFC. MS (ESI) calculated for (C12H12F3NO2) [M+H]⁺, 260.08; found, 260.10. 'H NMR (400 MHz, DMSO- ₆) 87.33 (d, J = 7.8 Hz, 1H), 7.20 (t, J = 74.4 Hz, 1H), 6.73 - 6.63 (m, 2H), 4.81 - 4.62 (m, 1H), 4.66 - 4.57 (m, 1H), 4.29 (d, J = 6.4 Hz, 1H), 2.94 - 2.84 (m, 1H), 2.72 - 2.57 (m, 1H), 2.39 - 1.97 (m, 3H). The relative and absolute stereochemistry for A39 isomer 1 is arbitrarily assigned.

Intermediate A40: rel-(4aS,10bS)-8-chloro-2,3,4,4a,6,10b-hexahydro-lH-pyrano[3,2-b:5,4- b']dipyridine hydrochloride

A40

Step-1:

[1119] To a stirred solution of methyl 3-bromo-6-chloropicolinate (50.0 g, 199.61 mmol) in 1,4-dioxane (500 mL) and H2O (50 mL) were added (E)-tert-butyldiphenyl((5-(4,4,5,5- tetramethyl-l,3,2-dioxaborolan-2-yl)pent-4-en-l-yl)oxy)silane (124.10 g, 275.47 mmol), Pd(dppf)Ch (14.61 g, 19.96 mmol) and K2CO3 (82.76 g, 598.85 mmol) at room temperature. The reaction mixture was stirred at 80 °C for 3 h under nitrogen atmosphere. The resulting mixture was diluted with water and extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SC>4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with PE / EtOAc (5:1) to afford methyl (E)-3-(5-((tert- butyldiphenylsilyl)oxy)pent-l-en-l-yl)-6-chloropicolinate (42.5 g, 43%) as a fight yellow oil. MS ESI calculated for C28H₃2ClNO₃Si [M+H]⁺, 494.18; found, 494.25.

Step-2: [1120] To a stirred solution of B0CNH2 (20.58 g, 175.67 mmol) in propan-l-ol (580 mL) was added a solution of NaOH (6.14 g, 153.57 mmol) in water (510 mL), then 1,3-dichloro- 5, 5-dimethylimidazolidine-2, 4-dione (22.33 g, 113.33 mmol) was added at 0 °C. The resulting mixture was stirred at room temperature for 30 min. This was followed by the addition of (DHQ)2-PHAL (6.07 g, 7.79 mmol, 0.1 M in propan-l-ol) (supplier: Shanghai Accela ChemBio Co., Ltd. CAS# 140924-50-1), then a solution of methyl (E)-3-(5-((tert- butyldiphenylsilyl)oxy)pent-l-en-l-yl)-6-chloropicolinate (39 g, 79.08 mmol) in propan-l-ol (440 mL) was added dropwise at 0 °C, after that, K2OSO4.2H2O (2.09 g, 5.66 mmol) was added in portions at 0 °C. The resulting mixture was stirred at room temperature for 16 h. The reaction mixture was diluted with water and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under vacuum. The residue was purified by silica gel column chromatography, eluted with PE / EtOAc (5:1) to afford rel-tert-butyl ((5S,6S)-6-(3-((tert- butyldiphenylsilyl)oxy)propyl)-2-chloro-8-oxo-5,8-dihydro-6H-pyrano[3,4-b]pyridin-5- yl)carbamate (9.2 g, 27%) as a green oil. MS ESI calculated for C32H39ClN2OsSi [M+H]⁺, 595.23; found, 595.30.

Step-3:

[1121] To a stirred solution of rel-tert-butyl ((5S,6S)-6-(3-((tert- butyldiphenylsilyl)oxy)propyl)-2-chloro-8-oxo-5,8-dihydro-6H-pyrano[3,4-b]pyridin-5- yl)carbamate (17.00 g, 28.56 mmol) in THF (170 mL) was added NaBIL (1.08 g, 28.56 mmol) at 0 °C. The resulting mixture was stirred at room temperature for 1 h. The reaction was quenched with ice water at 0 °C. The resulting mixture was extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SO4. The resulting mixture was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with PE / EtOAc (3/1) to afford rel-tert-butyl ((lS,2S)-5- ((tert-butyldiphenylsilyl)oxy)-l-(6-chloro-2-(hydroxymethyl)pyridin-3-yl)-2- hydroxypentyl)carbamate (12.00 g, 70%) as a colorless oil. MS ESI calculated for C₃2H43ClN2O₅Si [M+H]⁺, 599.26; found, 599.25.

Step-4:

[1122] To a stirred solution of rel-tert-butyl ((lS,2S)-5-((tert-butyldiphenylsilyl)oxy)-l-(6- chloro-2-(hydroxymethyl)pyridin-3-yl)-2-hydroxypentyl)carbamate (12.00 g, 20.03 mmol) in Toluene (120 mL) was added 2-(tributyl-X⁵-phosphaneylidene)acetonitrile (CAS No. 157141- 27-0) (9.67 g, 40.05 mmol ) at room temperature. The resulting mixture was stirred at 110 °C for 2 h under nitrogen atmosphere. The resulting mixture was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with PE / EtOAc (10/1) to afford rel-tert-butyl ((5S,6S)-6-(3-((tert-butyldiphenylsilyl)oxy)propyl)-2- chloro-5,8-dihydro-6H-pyrano[3,4-b]pyridin-5-yl)carbamate (6.04 g, 52%) as a white solid. MS ESI calculated for C₃2H4iClN₂O4Si [M+H]⁺, 581.25; found, 581.25.

Step-5:

[1123] To a stirred solution of rel-tert-butyl ((5S,6S)-6-(3-((tert- butyldiphenyIsilyl)oxy)propyl)-2-chIoro-5,8-dihydro-6H-pyrano[3,4-b]pyridin-5- yl)carbamate (6.04 g, 10.39 mmol) in THF (60 mL) was added TBAF (5.43 g, 20.78 mmol) at room temperature. The resulting mixture was stirred at room temperature for 2 h. The resulting mixture was diluted with water. The resulting mixture was extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SO4. The filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with PE / EtOAc (10/1) to afford rel-tert-butyl ((5S,6S)-2- chloro-6-(3-hydroxypropyl)-5,8-dihydro-6H-pyrano[3,4-b]pyridin-5-yl)carbamate (3.32 g, 93%) as a colorless oil. MS ESI calculated for (C16H23CIN2O4) [M+H]⁺, 343.13; found, 343.15.

Step-6:

[1124] To a stirred solution of rel-tert-butyl ((5S,6S)-2-chloro-6-(3-hydroxypropyl)-5,8- dihydro-6H-pyrano[3,4-b]pyridin-5-yl)carbamate (3.32 g, 9.68 mmol) in Toluene (33 mL) was added 2-(tributyl-X⁵-phosphancylidcnc)acctonitrilc (CAS No. 157141-27-0) (4.67 g, 19.37 mmol) at room temperature. The resulting mixture was stirred at 110 °C for 2 h under nitrogen atmosphere. The resulting mixture was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with PE / EtOAc (5/1) to afford rel-tert-butyl (4aS,10bS)-8-chloro-2,3,4,4a,6,10b-hexahydro-lH-pyrano[3,2-b:5,4- b']dipyridine-l -carboxylate (2.76 g, 88%) as a white solid. MS ESI calculated for (C16H21CIN2O3) [M+H]⁺, 325.12; found, 325.15.

Step-7:

[1125] To a stirred solution of rel-tert-butyl (4aS,10bS)-8-chloro-2,3,4,4a,6,10b- hexahydro-lH-pyrano[3,2-b:5,4-b']dipyridine-l-carboxylate (2.76 g, 8.50 mmol) in HC1 in 1,4-dioxane (4.0 M) (28 mL) at 0 °C. The resulting mixture was stirred at room temperature for 1 h. The resulting mixture was concentrated under reduced pressure. The racemic compound was separated by Prep-Chiral SFC with the following conditions: [Column: CHIRAL ART Amylose-SA, 5*25 cm, 5 pm; Mobile Phase A: CO2, Mobile Phase B: MEOH (0.1% 2M NH3-MEOH); Flow rate: 140 mL/min; Gradient (B%): isocratic 20% B;

RTl(min): 7.8; RT2(min): 11; Sample Solvent: MEOH] to afford rel-(4aS,10bS)-8-chloro- 2,3,4,4a,6,10b-hexahydro-lH-pyrano[3,2-b:5,4-b']dipyridine (A40) (1.63 g, 67%) as a white solid with retention time at 11 minute. MS ESI calculated for (C11H13CIN2O) [M+H]⁺, 225.07; found, 225.15. *H NMR (400 MHz, DMSO-d₆) 8 8.20 (d, J = 8.4 Hz, 1H), 7.55 (d, J = 8.4 Hz, 1H), 4.87 - 4.77 (m, 2H), 4.40 (s, 1H), 4.06 - 4.04 (m, 1H), 3.22 - 3.17 (m, 1H), 3.06 - 2.98 (m, 1H), 2.03 - 1.98 (m, 1H), 1.93 - 1.84 (m, 2H), 1.69 - 1.64 (m, 1H).

[1126] The absolute stereochemistry of A40 was determined as S, S-configuration, by single crystal crystallography of a compound prepared using A40. Accordingly, A40 is represented by the structure:

Intermediate A41 isomer 1: rel-(4aR,6S,10bS)-8-(difluoromethoxy)-6-methyl- 2,3,4,4a,6,10b-hexahydro-lH-isochromeno[4,3-b]pyridine, isomer 1 and,

Intermediate A41 isomer 2: rel-(4aR,6S,10bS)-8-(difluoromethoxy)-6-methyl-

2,3,4,4a,6,10b-hexahydro-lH-isochromeno[4,3-b]pyridine, isomer 2

Intermediate A41 isomer 3: rel-(4aR,6S,10bS)-8-(difluoromethoxy)-6-methyl- 2,3,4,4a,6,10b-hexahydro-lH-isochromeno[4,3-b]pyridine, isomer 3 and,

Intermediate A41 isomer 4: rel-(4aR,6S,10bS)-8-(difluoromethoxy)-6-methyl-

2,3,4,4a,6,10b-hexahydro-lH-isochromeno[4,3-b]pyridine, isomer 4

Isomer 4

Step-1:

[1127] To a stirred solution of 2-bromo-5-hydroxybenzaldehyde (30.0 g, 149.24 mmol) and

K2CO3 (61.9 g, 447.72 mmol) in DMF (300 mL) was added sodium 2-chloro-2,2- difluoroacetate (68.3 g, 447.72 mmol). The resulting mixture was stirred at 90 °C for 2 h under nitrogen atmosphere. The resulting mixture was filtered, the filter cake was washed with ethyl acetate. The filtrate was concentrated under reduced pressure. The mixture was diluted with water. The aqueous layer was extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous Na2SO4. The resulting mixture was concentrated under reduced pressure. The residue was purified by flash column chromatography with 0-50% ethyl acetate in petroleum ether to afford 2-bromo-5- (difluoromethoxy)benzaldehyde (11.0 g, 29%) as a white semi-solid. MS ESI calculated for C₈H₅BrF2O2 [M+H]⁺, 250.94, 252.94; found, 250.90, 252.85.

Step-2:

[1128] To a stirred solution of 2-bromo-5-(difluoromethoxy)benzaldehyde (10.5 g, 52.23 mmol) in THF (50 mL) was slowly added methylmagnesium bromide (3M in 2-MeTHF) (78 mL, 234 mmol) at -40 °C under nitrogen atmosphere. The mixture was stirred at -40 °C for 3 h. The mixture was quenched with NH4CI (sat.). The aqueous layer was extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous Na2SC>4. The resulting mixture was concentrated under reduced pressure. The residue was purified by flash column chromatography with 0-20% ethyl acetate in petroleum ether to afford a 1:1 mixture of (R)-l-(2-bromo-5-(difluoromethoxy)phenyl)ethan-l-ol and (S)-l-(2-bromo-5- (difluoromethoxy)phenyl)ethan-l-ol (8.5 g, 65%) as a yellow oil. MS ESI calculated for C₉H9BrF₂O2 [M+H]⁺, 266.98/268.98; found, 266.85/268.95.

Step-3: [1129] To a stirred solution of a 1:1 mixture of (R)-l-(2-bromo-5- (difluoromethoxy)phenyl)ethan-l-ol and (S)-l-(2-bromo-5-(difluoromethoxy)phenyl)ethan-l- ol (3.5 g, 13.09 mmol) and 3-fluoro-2-(tributylstannyl)pyridine (6.0 g, 15.72 mmol) in DMF (30 mL) were added Pd(PPhs)4 (1.5 g, 1.30 mmol) and CuO (0.2 g, 2.63 mmol). The mixture was stirred at 100 °C for 16 h under nitrogen atmosphere. The resulting mixture was filtered, the filter cake was washed with ethyl acetate. The filtrate was concentrated under reduced pressure. The residue was purified by flash column chromatography with 0-80% ethyl acetate in petroleum ether to afford a 1:1 mixture of (R)-l-(5-(difluoromethoxy)-2-(3- fluoropyridin-2-yl)phenyl)ethan- l-ol and (S)- l-(5-(difluoromethoxy)-2-(3-fluoropyridin-2- yl)phenyl)ethan-l-ol (2.8 g, 75%) as a yellow oil. MS ESI calculated for C14H12F3NO2 [M+H]⁺, 284.08; found, 283.95.

Step-4:

[1130] To a stirred solution of a 1:1 mixture of (R)-l-(5-(difluoromethoxy)-2-(3- fluoropyridin-2-yl)phenyl)ethan- l-ol and (S)- l-(5-(difhioromethoxy)-2-(3-fhioropyridin-2- yl)phenyl)ethan-l-ol (2.8 g, 9.89 mmol) in DMF (30 mL) was added NaH (60% in mineral oil) (0.4 g, 10 mmol) at 0 °C. The mixture was stirred at 80 °C for 2 h. The resulting mixture was quenched with ice water. The aqueous layer was extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous Na2SC>4. The resulting mixture was concentrated under reduced pressure. The residue was purified by flash column chromatography with 0-80% ethyl acetate in petroleum ether to afford a 1 : 1 mixture of (R)-8-(difluoromethoxy)-6-methyl-6H-isochromeno[4,3-b]pyridine and (S)-8- (difhioromethoxy)-6-methyl-6H-isochromeno[4,3-b]pyridine (2.2 g, 84%) as a yellow oil. MS ESI calculated for C14H11F2NO2 [M+H]⁺, 264.08; found, 264.00.

Step-5:

[1131] To a stirred solution of a 1:1 mixture of (R)-8-(difluoromethoxy)-6-methyl-6H- isochromeno[4,3-b]pyridine and (S)-8-(difhioromethoxy)-6-methyl-6H-isochromeno[4,3- b]pyridine (2.5 g, 9.50 mmol) and HC1 (cone. 5 mL) in methanol (50 mL) was added PtCh (2.50 g, 11.02 mmol). The mixture was stirred at 20 °C for 16 h under hydrogen atmosphere. The resulting mixture was filtered, the filter cake was washed with MeOH. The filtrate was concentrated under reduced pressure to afford a 1 : 1 :8:8 mixture of rel-(4aR,6S,10bS)-8- (difluoromethoxy)-6-methyl-2,3,4,4a,6,10b-hexahydro-lH-isochromeno[4,3-b]pyridine isomer 1 and rel-(4aR,6S,10bS)-8-(difluoromethoxy)-6-methyl-2,3,4,4a,6,10b-hexahydro- lH-isochromeno[4,3-b]pyridine isomer 2 and rel-(4aR,6S,10bS)-8-(difluoromethoxy)-6- methyl-2,3,4,4a,6,10b-hexahydro-lH-isochromeno[4,3-b]pyridine isomer 3 and rel- (4aR,6S,10bS)-8-(difluoromethoxy)-6-methyl-2,3,4,4a,6,10b-hexahydro-lH- isochromeno[4,3-b]pyridine isomer 4 (2.2 g, crude) as a white solid. MS ESI calculated for C14H17F2NO2 [M+H]⁺, 270.12; found, 270.10.

Step-6:

[1132] The 1 : 1 :8:8 mixture of rel-(4aR,6S,10bS)-8-(difluoromethoxy)-6-methyl- 2,3,4,4a,6,10b-hexahydro-lH-isochromeno[4,3-b]pyridine isomer 1 and rel-(4aR,6S,10bS)-8- (difluoromethoxy)-6-methyl-2,3,4,4a,6,10b-hexahydro-lH-isochromeno[4,3-b]pyridine isomer 2 and rel-(4aR,6S,10bS)-8-(difluoromethoxy)-6-methyl-2,3,4,4a,6,10b-hexahydro- lH-isochromeno[4,3-b]pyridine isomer 3 and rel-(4aR,6S,10bS)-8-(difluoromethoxy)-6- methyl-2,3,4,4a,6,10b-hexahydro-lH-isochromeno[4,3-b]pyridine isomer 4 (2.2 g) was separated by Prep-Achiral-SFC with the following conditions: [Column: GreenSep Basic 3*15 cm, 5 [xmL; Mobile Phase A: CO2, Mobile Phase B: IPA (20mM NH3); Flow rate: 75 mL/min; Gradient (B%): isocratic 23% B; Column Temperature(°C): 35; Back Pressure(bar): 100; Wave Length: 220 nm; RTl(min): 2.45; RT2(min): 3.10; Sample Solvent: MEOH] to afford a 1:1 mixture of rel-(4aR,6S,10bS)-8-(difluoromethoxy)-6-methyl-2,3,4,4a,6,10b- hexahydro-lH-isochromeno[4,3-b]pyridine isomer 1 and rel-(4aR,6S,10bS)-8- (difluoromethoxy)-6-methyl-2,3,4,4a,6,10b-hexahydro-lH-isochromeno[4,3-b]pyridine isomer 2 (220 mg) as a yellow oil.

[1133] The chiral resolution also afforded a 1:1 mixture of rel-(4aR,6S,10bS)-8- (difhioromethoxy)-6-methyl-2,3,4,4a,6,10b-hexahydro-lH-isochromeno[4,3-b]pyridine isomer 3 and rel-(4aR,6S,10bS)-8-(difhioromethoxy)-6-methyl-2,3,4,4a,6,10b-hexahydro- lH-isochromeno[4,3-b]pyridine isomer 4 (1.1 g) as a yellow oil.

[1134] A 1:1 mixture of rel-(4aR,6S,10bS)-8-(difluoromethoxy)-6-methyl-2,3,4,4a,6,10b- hexahydro-lH-isochromeno[4,3-b]pyridine isomer 1 and rel-(4aR,6S,10bS)-8- (difluoromethoxy)-6-methyl-2,3,4,4a,6,10b-hexahydro-lH-isochromeno[4,3-b]pyridine isomer 2 (220 mg) was separated by Prep-Chiral-HPLC with the following conditions: [Column: CHIRALPAK IF, 2*25 cm, 5 pm; Mobile Phase A: Hex (0.5% 2M NH3-MeOH), Mobile Phase B: ETOH: DCM=1: 1; Flow rate: 20 mL/min; Gradient (B%): 5% B to 5% B in 13 min; Wave Length: 220/254 nm; RTl(min): 9.31; RT2(min): 10.79; Sample Solvent: EtOH: DCM=1 : 1— HPLC] to afford rel-(4aR,6S,10bS)-8-(difluoromethoxy)-6-methyl- 2,3,4,4a,6,10b-hexahydro-lH-isochromeno[4,3-b]pyridine isomer 1 (A41 isomer 1) (40 mg) as a white solid with shorter retention time and rel-(4aR,6S,10bS)-8-(difluoromethoxy)-6- methyl-2,3,4,4a,6,10b-hexahydro-lH-isochromeno[4,3-b]pyridine isomer 2 (A41 isomer 2) (40.2 mg) as a yellow solid with longer retention time.

[1135] rel-(4aR,6S, 10bS)-8-(difluoromethoxy)-6-methyl-2,3,4,4a,6, 1 Ob-hexahydro- 1 H- isochromeno[4,3-b]pyridine isomer 1 (A41 isomer 1): MS ESI calculated for C14H17F2NO2 [M+H]⁺, 270.12; found, 270.10. ^XH NMR (400 MHz, DMSO-J₆) 3 7.59 - 7.53 (m, 1H), 7.20 (t, J = 74.4 Hz, 1H), 7.05 - 7.00 (m, 1H), 6.96 (d, J = 2.4 Hz, 1H), 4.91 - 4.84 (m, 1H), 3.34 - 3.27 (m, 1H), 3.17 - 3.09 (m, 1H), 3.03 - 2.94 (m, 1H), 2.61 - 2.53 (m, 1H), 2.46 - 2.29 (m, 1H), 2.04 - 1.96 (m, 1H), 1.73 - 1.64 (m, 1H), 1.50 - 1.36 (m, 4H). The relative stereochemistry of two centers labeled with “orl” was determined by NOESY.

[1136] rel-(4aR,6S, 10bS)-8-(difluoromethoxy)-6-methyl-2, 3, 4, 4a, 6, lOb-hexahydro- 1H- isochromeno[4,3-b]pyridine isomer 2 (A41 isomer 2): MS ESI calculated for C14H17F2NO2 [M+H]⁺, 270.12; found, 270.10. 'H NMR (400 MHz, DMSO-7₆) 8 7.59 - 7.53 (m, 1H), 7.20 (t, 7= 74.4 Hz, 1H), 7.05 - 7.00 (m, 1H), 6.96 (d, 7 = 2.4 Hz, 1H), 4.91 - 4.84 (m, 1H), 3.34

- 3.27 (m, 1H), 3.17 - 3.09 (m, 1H), 3.03 - 2.94 (m, 1H), 2.61 - 2.53 (m, 1H), 2.46 - 2.29 (m, 1H), 2.04 - 1.96 (m, 1H), 1.73 - 1.64 (m, 1H), 1.50 - 1.36 (m, 4H). The relative stereochemistry of two centers labeled with “orl” was determined by NOESY.

[1137] A 1:1 mixture of rel-(4aR,6S,10bS)-8-(difluoromethoxy)-6-methyl-2,3,4,4a,6,10b- hexahydro-lH-isochromeno[4,3-b]pyridine isomer 3 and rel-(4aR,6S,10bS)-8- (difluoromethoxy)-6-methyl-2,3,4,4a,6,10b-hexahydro-lH-isochromeno[4,3-b]pyridine isomer 4 (1100 mg) was separated by Prep-Chiral-SFC with the following conditions: [Column: CHIRALPAK IG, 3*25 cm, 5 pm; Mobile Phase A: CO2, Mobile Phase B: MEOH (0.1% 2M NH3-MEOH); Flow rate: 80 mL/min; Gradient (B%): isocratic 20% B; RTl(min): 3.5; RT2(min): 6; Sample Solvent: MEOH] to afford rel-(4aR,6S,10bS)-8-(difhioromethoxy)- 6-methyl-2,3,4,4a,6,10b-hexahydro-lH-isochromeno[4,3-b]pyridine isomer 3 (A41 isomer 3) (423 mg) as a white solid with shorter retention time and rel-(4aR,6S,10bS)-8- (difluoromethoxy)-6-methyl-2,3,4,4a,6,10b-hexahydro-lH-isochromeno[4,3-b]pyridine isomer 4 (A41 isomer 4) (428 mg) as a white solid with longer retention time.

[1138] rel-(4aR,6S,10bS)-8-(difluoromethoxy)-6-methyl-2,3,4,4a,6,10b-hexahydro-lH- isochromeno[4,3-b]pyridine isomer 3 (A41 isomer 3): MS ESI calculated for C14H17F2NO2 [M+H]⁺, 270.12; found, 270.10. 'H NMR (400 MHz, DMSO-7₆) 8 7.44 - 7.22 (m, 2H), 7.07

- 6.99 (m, 2H), 4.76 (q, 7 = 6.4 Hz, 1H), 3.63 - 3.62 (m, 1H), 3.53 - 3.52 (m, 1H), 2.99 - 2.92 (m, 1H), 2.74 - 2.63 (m, 1H), 2.01 - 1.92 (m, 1H), 1.79 - 1.69 (m, 1H), 1.67 - 1.57 (m, 1H), 1.51 (d, 7= 6.4 Hz, 3H), 1.40 - 1.31 (m, 1H). The relative stereochemistry of two centers labeled with “orl” was determined by NOESY.

[1139] rel-(4aR,6S, 10bS)-8-(difhioromethoxy)-6-methyl-2, 3, 4, 4a, 6, lOb-hexahydro- 1H- isochromeno[4,3-b]pyridine isomer 4 (A41 isomer 4): MS ESI calculated for C14H17F2NO2 [M+H]⁺, 270.12; found, 270.10. 'H NMR (400 MHz, DMSO-7₆) 8 7.44 - 7.22 (m, 2H), 7.07

- 6.99 (m, 2H), 4.76 (q, 7 = 6.4 Hz, 1H), 3.63 - 3.62 (m, 1H), 3.53 - 3.52 (m, 1H), 2.99 - 2.92 (m, 1H), 2.74 - 2.63 (m, 1H), 2.01 - 1.92 (m, 1H), 1.79 - 1.69 (m, 1H), 1.67 - 1.57 (m, 1H), 1.51 (d, J- 6.4 Hz, 3H), 1.40 - 1.31 (m, 1H). The relative stereochemistry of two centers labeled with “orl” was determined by NOESY.

Intermediate A42: 1:1 mixture of rel-(2R,4aR,9bR)-2-methyl-7-(trifluoromethyl)-

2,3,4,4a,5,9b-hexahydro-lH-indeno[l,2-b]pyridine isomer 2 and rel-(2S,4aS,9bS)-2-methyl-

7-(trifluoromethyl)-2,3,4,4a,5,9b-hexahydro-lH-indeno[l,2-b]pyridine isomer 1

[1140] A mixture of (4-(trifluoromethyl)phenyl)boronic acid (19 g, 100.04 mmol), methyl 2-chloro-6-methylnicotinate (22.28 g, 120.04 mmol), NazCCh (41.48 g, 300.11 mmol) and tetrakis(triphenylphosphine)palladium (2.31 g, 2.00 mmol) in a mixture of toluene (100 mL), H2O (50 mL) and EtOH (100 mL) was stirred at 120°C for 16 h under nitrogen atmosphere. The resulting mixture was quenched by water and extracted with CH2CI2. The combined organic layers were washed with brine, dried over anhydrous Na2SC>4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by normal phase flash chromatography with a 330 g silica gel column and eluted with 0 - 15% ethyl acetate in petroleum ether to afford methyl 6-methyl-2-(4-(trifluoromethyl)phenyl)nicotinate (19.5 g, 44%) as an off-white oil. MS ESI calculated for C15H12F3NO2 [M+H]⁺, 296.08; found, 296.10.

Step-2:

[1141] To a stirred solution of methyl 6-methyl-2-(4-(trifluoromethyl)phenyl)nicotinate (19.50 g, 66.38 mmol) and CaCl₂ (11.05 g, 99.57 mmol) in THF (150 mL) and EtOH (150 mL) was added NaBFL (6.28 g, 165.96 mmol) at 0 °C. The resulting mixture was stirred at room temperature for 16 h. The reaction was quenched with water/ice. The resulting mixture was extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na₂SO4. After filtration, the filtrate was concentrated under reduced pressure to afford (6-methyl-2-(4-(trifluoromethyl)phenyl)pyridin-3-yl)methanol (17 g, 86%) as a white solid. MS ESI calculated for CI₄HI₂F₃NO [M+H]⁺, 268.09; found, 268.15.

Step-3:

[1142] To a stirred solution of (6-methyl-2-(4-(trifluoromethyl)phenyl)pyridin-3- yl)methanol (17 g, 63.61 mmol) in DCM (200 mL) was added SOCh (14 mL, 190.83 mmol) dropwise at 0 °C. The resulting mixture was stirred at room temperature for 2 h. The resulting mixture was concentrated under reduced pressure to afford 3-(chloromethyl)-6-methyl-2-(4- (trifhioromethyl)phenyl)pyridine (23.4 g, crude) as a yellow oil. MS ESI calculated for C14H11CIF3N [M+H]⁺, 286.05; found, 286.05.

Step-4:

[1143] To a stirred solution of 3-(chloromethyl)-6-methyl-2-(4-

(trifhioromethyl)phenyl)pyridine (23.40 g, 81.91 mmol) and Na₂CO₃ (34.72 g, 327.63 mmol) in DME (250 mL) were added P(m-Tol)₃ (4.99 g, 16.38 mmol) and Pd(OAc)₂ (1.84 g, 8.19 mmol) at room temperature under nitrogen atmosphere. The resulting mixture was stirred at 110 °C for 16 h. The reaction mixture was quenched by water and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under vacuum. The resulting residue was purified by normal phase flash chromatography with a 330 g silica gel column and eluted with 0-20% ethyl acetate in petroleum ether to afford 2-methyl-7-(trifluoromethyl)-5H-indeno[l,2- b]pyridine (9.0 g, 43%) as a light yellow solid. MS ESI calculated for C14H10F3N [M+H]⁺, 250.08; found, 250.20. 'H NMR (400 MHz, DMSO-7₆) 8 8.11 (d, J = 8.0 Hz, 1H), 8.07 - 7.98 (m, 1H), 7.94 (d, 7 = 7.8 Hz, 1H), 7.79 (dd, 7 = 7.6, 1.6 Hz, 1H), 7.26 (d, 7= 7.6 Hz, 1H), 4.00 (s, 2H), 2.60 (s, 3H).

Step-5:

[1144] To a stirred solution of 2-methyl-7-(trifluoromethyl)-5H-indeno[l,2-b]pyridine (2.8 g, 11.23 mmol) in Toluene (28 mL) were added N-phenylaniline (7.60 g, 44.94 mmol) and tris(2,3,4,5,6-pentafluorophenyl)borane (575 mg, 1.12 mmol) at 20 °C. The resulting mixture was stirred at 110 °C for 16 h. The mixture was basified with NaHCO₃ (sat.) to pH 8 and then extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na₂SO4. After filtration, the filtrate was concentrated under reduced pressure. The resulting residue was purified by normal phase flash chromatography with a 120 g silica gel column and eluted with 0-10% methanol in dichloromethane, the product was further purified by Prep-Achiral-SFC with the following conditions: [Column: YMC-Actus Triart Diol-HILIC 3*25 cm, 5 pm; Mobile Phase A: CO₂, Mobile Phase B: MeOH (20mM NH3.M); Flow rate: 75 mL/min; Gradient: isocratic 13% B; Column Temperature( C): 35; Back Pressure(bar): 100; Wave Length: 220 nm; RTl(min): 4.88; RT2(min): 5.62; Sample Solvent: MEOH] to afford a 1:1 mixture of rel-(2R,4aR,9bR)-2-methyl-7-(trifluoromethyl)- 2,3,4,4a,5,9b-hexahydro-lH-indeno[l,2-b]pyridine isomer 1 and rel-(2R,4aR,9bR)-2-methyl- 7-(trifluoromethyl)-2,3,4,4a,5,9b-hexahydro-lH-indeno[l,2-b]pyridine isomer 2 (489 mg, 88% purity) as a light yellow oil with retention time at 5.62 minute. MS ESI calculated for C14H16F3N [M+H]⁺, 256.12; found, 256.10. 'H NMR (400 MHz, DMSO-J₆) 5 7.69 - 7.40 (m, 3H), 4.06 (d, J = 5.2 Hz, 1H), 3.06 - 2.89 (m, 1H), 2.82 - 2.57 (m, 2H), 2.40 - 2.22 (m, 1H), 1.91 - 1.68 (m, 2H), 1.57 - 1.41 (m, 1H), 1.31 - 1.10 (m, 1H), 1.04 - 0.90 (m, 3H).

Intermediate A42 isomer 1: rel-(2R,4aR,9bR)-2-methyl-7-(trifluoromethyl)-2,3,4,4a,5,9b- hexahydro-lH-indeno[l,2-b]pyridine isomer 1:

Intermediate A42 isomer 2: rel-(2R,4aR,9bR)-2-methyl-7-(trifluoromethyl)-2,3,4,4a,5,9b- hexahydro-lH-indeno[l,2-b]pyridine isomer 2:

[1145] Intermediate A42 (489 mg) was separated by Prep-Chiral-HPLC with the following conditions: [Column: CHIRALPAK IG, 2*25 cm, 5 pm; Mobile Phase A: Hex(0.5% 2M NHs-MeOH), Mobile Phase B: MEOH: DCM=1 : 1— HPLC; Flow rate: 20 mL/min; Gradient: 2% B to 2% B in 11.5 min; Wave Length: 220/254 nm; RTl(min): 4.87; RT2(min): 7.03; Sample Solvent: EtOH: DCM=1: 1-HPLC] to afford rel-(2R,4aR,9bR)-2-methyl-7- (trifhioromethyl)-2,3,4,4a,5,9b-hexahydro-lH-indeno[l,2-b]pyridine isomer 1 (A42 isomer 1) (66 mg, 14% yield) as a light yellow oil with retention time at 4.87 minute. MS ESI calculated for Ci4Hi₆F₃N [M+H]⁺, 256.12; found, 256.10. *H NMR (400 MHz, DMSO-d₆) 8 7.66 - 7.37 (m, 3H), 3.99 (d, J= 5.2 Hz, 1H), 3.03 - 2.97 (m, 1H), 2.84 - 2.70 (m, 1H), 2.64 - 2.52 (m, 1H), 2.34 - 2.19 (m, 1H), 1.89 - 1.66 (m, 2H), 1.52 - 1.36 (m, 1H), 1.26 - 1.07 (m, 1H), 0.94 (d, J = 6.4 Hz, 3H). Absolute stereochemistry was not determined.

[1146] The chiral resolution also afforded rel-(2R,4aR,9bR)-2-methyl-7-(trifluoromethyl)- 2,3,4,4a,5,9b-hexahydro-lH-indeno[l,2-b]pyridine isomer 2 (A42 isomer 2) (61 mg, 12% yield) as a light yellow oil with retention time at 7.03 minute. MS ESI calculated for CI₄HI₆F₃N [M+H]⁺, 256.12; found, 256.10. 'H NMR (400 MHz, DMSO-J₆) 8 7.66 - 7.37 (m, 3H), 3.99 (d, J = 5.2 Hz, 1H), 3.03 - 2.97 (m, 1H), 2.84 - 2.70 (m, 1H), 2.64 - 2.52 (m, 1H), 2.34 - 2.19 (m, 1H), 1.89 - 1.66 (m, 2H), 1.52 - 1.36 (m, 1H), 1.26 - 1.07 (m, 1H), 0.94 (d, J = 6.4 Hz, 3H). Absolute stereochemistry was not determined.

Intermediate A43: rel-(4aS,10bS)-8-isopropyl-2,3,4,4a,6,10b-hexahydro-lH-pyrano[3,2- b:5,4-b']dipyridine hydrochloride

A43

Step-1: [1147] To a stirred solution of rel-tert-butyl (4aS,10bS)-8-chloro-2,3,4,4a,6,10b- hexahydro-lH-pyrano[3,2-b:5,4-b']dipyridine-l-carboxylate (from intermediate A40) (1.0 g, 3.07 mmol) and 4,4,5,5-tetramethyl-2-(prop-l-en-2-yl)-l,3,2-dioxaborolane (0.62 g, 3.69 mmol) in Dioxane (10 mL) were added Pd(dppf)C12-CH2C12 (0.25 g, 0.30 mmol) and K2CO3 (1.28 g, 9.23 mmol) at room temperature under nitrogen atmosphere. The mixture was stirred at 80 °C for 16 h. The reaction mixture was quenched with water and extracted with EtOAc. The combined organic layers were washed with EtOAc, dried over anhydrous Na2SO4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with PE / EtOAc (5: 1) to afford rel-tert-butyl (4aS,10bS)-8-(prop-l-en-2-yl)-2,3,4,4a,6,10b-hexahydro-lH-pyrano[3,2-b:5,4-b']dipyridine- 1-carboxylate (910 mg, 89%) as a colorless oil. MS ESI calculated for C19H26N2O3 [M+H]⁺, 331.19; found, 331.15.

Step-2:

[1148] To a solution of rel-tert-butyl (4aS,10bS)-8-(prop-l-en-2-yl)-2,3,4,4a,6,10b- hexahydro-lH-pyrano[3,2-b:5,4-b']dipyridine- 1-carboxylate (850 mg, 2.57 mmol) in methanol (10 mL) was added Pd/C (273 mg, 10% active on carbon). The mixture was stirred at 20 °C for 2 h under hydrogen atmosphere. The resulting mixture was filtered, the filter cake was washed with MeOH. The filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with PE / EtOAc (5:1) to afford rel-tert-butyl (4aS, 10bS)-8-isopropyl-2,3,4,4a,6, lOb-hexahydro- lH-pyrano[3,2-b:5,4- b']dipyridine- 1-carboxylate (790 mg, 92%) as a colorless oil. MS ESI calculated for C19H28N2O3 [M+H]⁺, 333.21; found, 333.15.

Step-3:

[1149] A mixture of rel-tert-butyl (4aS,10bS)-8-isopropyl-2,3,4,4a,6,10b-hexahydro-lH- pyrano[3,2-b:5,4-b']dipyridine-l-carboxylate (700 mg, 2.10 mmol) and HC1 (4M in dioxane) (2 mL) was stirred at 20 °C for 1 h. The resulting mixture was concentrated under reduced pressure to afford rel-(4aS,10bS)-8-isopropyl-2,3,4,4a,6,10b-hexahydro-lH-pyrano[3,2- b:5,4-b']dipyridine hydrochloride (A43) (760 mg, crude) as a white solid, which was used directly without purification. MS ESI calculated for C14H20N2O [M+H]⁺, 233.16; found, 233.15. 'H NMR (400 MHz, DMSO- ₆) 8 10.79 (br, 1H), 8.87 (br, 1H), 8.44 (d, J= 8.0 Hz, 1H), 7.64 (d, J = 8.0 Hz, 1H), 5.18 - 4.84 (m, 2H), 4.58 - 4.38 (m, 1H), 4.09 - 4.08 (m, 1H), 3.36 - 3.11 (m, 2H), 3.02 (q, J = 11.8 Hz, 1H), 2.14 - 1.53 (m, 4H), 1.44 - 1.13 (m, 6H).

[1150] The absolute stereochemistry of A43 was determined as S, S-configuration, prepared from A40, the absolute stereochemistry of which was confirmed. Accordingly, A43 is represented by the structure:

Intermediate A44: rel-(4aS,10bS)-8-cyclopropyl-2,3,4,4a,6,10b-hexahydro-lH-pyrano[3,2- b:5,4-b']dipyridine hydrochloride

A44

[1151] To a stirred mixture of rel-tert-butyl (4aS,10bS)-8-chloro-2,3,4,4a,6,10b-hexahydro- lH-pyrano[3,2-b:5,4-b']dipyridine-l-carboxylate (from intermediate A40) (1.0 g, 3.07 mmol) and K3PO4 (1.96 g, 9.23 mmol) in toluene (20 mL) and H2O (2 mL) were added Pd(OAc)2 (69 mg, 0.30 mmol) and cyclopropylboronic acid (661 mg, 7.69 mmol) at room temperature under nitrogen atmosphere. The resulting mixture was stirred at 80 °C for 16 h. The resulting mixture was concentrated under vacuum. The residue was purified by silica gel column chromatography, eluted with PE/EtOAc (5:1) to afford rel-tert-butyl (4aS,10bS)-8- cyclopropyl-2,3,4,4a,6,10b-hexahydro-lH-pyrano[3,2-b:5,4-b']dipyridine-l-carboxylate (1.0 g, 98%) as a colorless oil. MS ESI calculated for C19H26N2O3 [M+H]⁺, 331.19; found, 331.20.

Step-2:

[1152] A mixture of rel-tert-butyl (4aS, 10bS)-8-cyclopropyl-2,3,4,4a,6, 1 Ob-hexahydro- 1H- pyrano[3,2-b:5,4-b']dipyridine-l-carboxylate (1.0 g, 3.02 mmol) and HC1 (4M in dioxane) (10 mL) was stirred at room temperature for 1 h. The resulting mixture was concentrated under vacuum to afford rel-(4aS,10bS)-8-cyclopropyl-2,3,4,4a,6,10b-hexahydro-lH- pyrano[3,2-b:5,4-b']dipyridine hydrochloride (A44) (870 mg, crude) as an off-white solid, which was used in the next step directly without further purification. MS ESI calculated for C14H18N2O [M+H]⁺, 231.14; found, 231.25. 'H NMR (400 MHz, DMSO-J₆) 8 10.29 (s, 1H), 8.72 (s, 1H), 8.02 (d, J= 8.4 Hz, 1H), 7.31 (d, J= 8.0 Hz, 1H), 4.92 - 4.66 (m, 2H), 4.34 (d, J = 10.6 Hz, 1H), 4.03 - 4.02 (m, 1H), 3.18 (d, J = 12.4 Hz, 1H), 3.01 (q, J = 11.8 Hz, 1H), 2.22 - 2.16 (m, 1H), 2.05 - 1.58 (m, 4H), 1.15 - 0.88 (m, 4H).

[1153] The absolute stereochemistry of A44 was determined as S, S-configuration, prepared from A40, the absolute stereochemistry of which was confirmed. Accordingly, A44 is represented by the structure:

Intermediate A45 isomer 1: (4aS,6R,10bS)-6-methyl-8-(trifluoromethyl)-2,3,4,4a,6,10b- hexahydro- 1 H-pyrano[3,2-b:5,4-b']dipyridine

A45 isomer 1

Step-1:

[1154] To a stirred solution of methyl 3-bromo-6-(trifluoromethyl)picolinate (25.0 g, 88.02 mmol) in THF (250 mL) and H2O (50 mL) was added LiOH (4.22 g, 176.04 mmol) at room temperature . The resulting mixture was stirred at room temperature for 2 h. The mixture was acidified with HC1 (aq., IN) to PH 1. The resulting mixture was extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SO4. After filtration, the filtrate was concentrated under reduced pressure to afford 3-bromo-6- (trifhioromethyl)picolinic acid (42 g, crude) as a white solid. MS ESI calculated for (C7H₃BrF₃NO2) [M+H]⁺, 269.93, 271.93; found, 270.05, 272.05.

[1155] To a stirred solution of 3-bromo-6-(trifluoromethyl)picolinic acid (42 g, 155.55 mmol) and N,O-dimethylhydroxylamine hydrochloride (18.21 g, 186.66 mmol) in DMF (500 mL) were added HATU (70.98 g, 186.66 mmol) and DIEA (60.31 g, 466.66 mmol) at room temperature under nitrogen atmosphere. The resulting mixture was stirred at room temperature for 16 h. The reaction mixture was quenched by the addition of water and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under vacuum. The resulting residue was purified by normal phase flash chromatography with a 330 g silica gel column and eluted with 0-25% ethyl acetate in petroleum ether to afford 3-bromo-N-methoxy-N-methyl-6- (trifhioromethyl)picolinamide (29 g, 60%) as a yellow oil. MS ESI calculated for (C₉H₈BrF₃N₂O2) [M+H]⁺, 312.97, 314.97; found, 313.05, 315.05.

Step-3:

[1156] To a stirred solution of 3-bromo-N-methoxy-N-methyl-6- (trifluoromethyl)picolinamide (29 g, 92.63 mmol) in Diethyl ether (300 mL) was added MeMgBr (3M in Et2O) (93 mL, 279 mmol) dropwise at 0 °C under nitrogen atmosphere. The resulting mixture was stirred at room temperature for 2 h. The reaction mixture was quenched by the addition of ice water and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under vacuum. The resulting residue was purified by normal phase flash chromatography with a 330 g silica gel column and eluted with 0-10% ethyl acetate in petroleum ether to afford l-(3-bromo-6-(trifluoromethyl)pyridin-2-yl)ethan-l-one (13.8 g, 56%) as a brown oil. MS ESI calculated for C₈H₅BrF₃NO [M+H]⁺, 267.95, 269.95; found, 268.00, 270.00.

Step-4:

[1157] To a stirred solution of l-(3-bromo-6-(trifluoromethyl)pyridin-2-yl)ethan-l-one (13.30 g, 49.62 mmol) and (E)-tert-butyldiphenyl((5-(4,4,5,5-tetramethyl-l,3,2-dioxaborolan- 2-yl)pent-4-en-l-yl)oxy)silane (28.26 g, 59.54 mmol) in Dioxane (150 mL) and H2O (15 mL) were added K2CO3 (13.72 g, 99.24 mmol) and Pd(dppf)C12-CH2C12 (4.05 g, 4.96 mmol) at room temperature under nitrogen atmosphere. The resulting mixture was stirred at 100 °C for 16 h. The reaction mixture was quenched by the addition of water and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under vacuum. The resulting residue was purified by normal phase flash chromatography with a 330 g silica gel column and eluted with 0-8% ethyl acetate in petroleum ether to afford (E)-l-(3-(5-((tert-butyldiphenylsilyl)oxy)pent-l-en- l-yl)-6-(trifhioromethyl)pyridin-2-yl)ethan-l-one (17.6 g, 69%) as a yellow oil. MS ESI calculated for C29H32F₃NO₂Si [M+H]⁺, 512.22; found, 512.25.

[1158] To a stirred solution of (E)-l-(3-(5-((tert-butyldiphenylsilyl)oxy)pent-l-en-l-yl)-6-

(trifhioromethyl)pyridin-2-yl)ethan-l-one (17.6 g, 34.40 mmol) in methanol (300 mL) was added NaBFL (1.95 g, 51.60 mmol) at 0 °C. The resulting mixture was stirred at room temperature for 2 h. The reaction mixture was quenched by the addition of ice water and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under vacuum. The resulting residue was purified by normal phase flash chromatography with a 330 g silica gel column and eluted with 0-10% ethyl acetate in petroleum ether to afford a 1:1 mixture of (R,E)-l-(3-(5-((tert- butyldiphenylsilyl)oxy)pent- 1-en- 1 -yl)-6-(trifhioromethyl)pyridin-2-yl)ethan- 1 -ol and (S,E)- 1 -(3-(5-((tert-butyldiphenylsilyl)oxy)pent- 1 -en- l-yl)-6-(trifhioromethyl)pyridin-2-yl)ethan- 1 - ol (15.4 g, 87%) as a yellow oil. MS ESI calculated for C29H₃4F₃NO2Si [M+H]⁺, 514.23; found, 514.30.

Step-6:

[1159] To a stirred solution of tert-butyl carbamate (10.89 g, 92.94 mmol) in propan-l-ol (116 mL) was added a solution of NaOH (3.24 g, 80.95 mmol) in H2O (110 mL) at room temperature. The mixture was stirred at room temperature for 10 min. Then l,3-dichloro-5,5- dimethylimidazolidine-2, 4-dione (8.86 g, 44.97 mmol) was added to the mixture at room temperature. The mixture was stirred at room temperature for 30 min. This was followed by the addition of a solution of (DHQ)2PHAL (2.34 g, 2.99 mmol) (supplier: Shanghai Accela ChemBio Co., Ltd. CAS# 140924-50-1) in propan-l-ol (30 mL) and a solution of 1:1 mixture of (R,E)- 1 -(3-(5-((tert-butyldiphenylsilyl)oxy)pent- 1 -en- 1 -yl)-6-(trifhioromethyl)pyridin-2- yl)ethan-l-ol and (S,E)-l-(3-(5-((tert-butyldiphenylsilyl)oxy)pent-l-en-l-yl)-6- (trifhioromethyl)pyridin-2-yl)ethan-l-ol (15.4 g, 29.980 mmol, 1 equiv) in propan-l-ol (20 mL) at 0 °C. Then Potassium osmate(VI) dihydrate (1.10 g, 2.99 mmol) was added at at 0 °C. The resulting mixture was stirred at room temperature for 16 h. The reaction mixture was quenched by the addition of brine and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under vacuum. The residue was purified by normal phase flash chromatography with a 330 g silica gel column and eluted with 0-20% ethyl acetate in petroleum ether to afford tert-butyl ((lS,2S)-5-((tert-butyldiphenylsilyl)oxy)-2-hydroxy-l-(2-((S)-l- hydroxyethyl)-6-(trifluoromethyl)pyridin-3-yl)pentyl)carbamate (8.3 g, 43%) as a yellow oil as the second eluting peak. MS ESI calculated for Cs^sFs^OsSi [M+H]⁺, 647.30; found, 647.20.

[1160] The purification process also afforded tert-butyl ((lS,2S)-5-((tert- butyldiphenylsilyl)oxy)-2-hydroxy-l-(2-((R)-l-hydroxyethyl)-6-(trifluoromethyl)pyridin-3- yl)pentyl)carbamate (6.9 g, 36%) as a yellow oil as the first eluting peak. MS ESI calculated for C34H₄5F₃N2O5Si [M+H]⁺, 647.30; found, 647.20.

Step-7:

[1161] To a stirred solution of tert-butyl ((lS,2S)-5-((tert-butyldiphenylsilyl)oxy)-2- hydroxy-1 -(2-((S)- 1 -hydroxyethyl)-6-(trifluoromethyl)pyridin-3-yl)pentyl)carbamate (8.3 g, 12.83 mmol) in toluene (100 mL) was added 2-(tributyl-X⁵-phosphaneylidene)acetonitrile (CAS No. 157141-27-0) (6.19 g, 25.67 mmol) at room temperature under nitrogen atmosphere. The resulting mixture was stirred at 100 °C for 16 h. The resulting mixture was concentrated under vacuum. The residue was purified by normal phase flash column chromatography with a 120 g silica gel column and eluted with 0-10% ethyl acetate in petroleum ether to afford tert-butyl ((5S,6S,8R)-6-(3-((tert-butyldiphenylsilyl)oxy)propyl)-8- methyl-2-(trifluoromethyl)-5,8-dihydro-6H-pyrano[3,4-b]pyridin-5-yl)carbamate (2.45 g, 30%) as a light yellow oil. MS ESI calculated for C₃4H4₃F₃N2C>4Si [M+H]⁺, 629.29; found, 629.45.

Step-8:

[1162] To a stirred solution of tert-butyl ((5S,6S,8R)-6-(3-((tert- butyldiphenylsilyl)oxy)propyl)-8-methyl-2-(trifluoromethyl)-5,8-dihydro-6H-pyrano[3,4- b]pyridin-5-yl)carbamate (2.45 g, 3.90 mmol) in THF (30 mL) was added TBAF (1.22 g, 4.68 mmol) at 0 °C. The resulting mixture was stirred at room temperature for 16 h. The mixture was concentrated under vacuum. The residue was purified by normal phase flash column chromatography with an 80 g silica gel column and eluted with 0-60% ethyl acetate in petroleum ether to afford tert-butyl ((5S,6S,8R)-6-(3-hydroxypropyl)-8-methyl-2- (trifhioromethyl)-5,8-dihydro-6H-pyrano[3,4-b]pyridin-5-yl)carbamate (1.36 g, 89%) as a light yellow oil. MS ESI calculated for C18H25F3N2O4 [M+H]⁺, 391.18; found, 391.15.

Step-9:

[1163] To a stirred solution of ((5S,6S,8R)-6-(3-hydroxypropyl)-8-methyl-2- (trifhioromethyl)-5,8-dihydro-6H-pyrano[3,4-b]pyridin-5-yl)carbamate (1.36 g, 3.48 mmol) in toluene (15 mL) was added 2-(tributyl-A,⁵-phosphaneylidene)acetonitrile (CAS No.

157141-27-0) (1.68 g, 6.97 mmol) at room temperature under nitrogen atmosphere. The resulting mixture was stirred at 100 °C for 16 h. The reaction mixture was concentrated under vacuum. The residue was purified by normal phase flash column chromatography with an 80 g silica gel column and eluted with 0-20% ethyl acetate in petroleum ether to afford tertbutyl (4aS,6R,10bS)-6-methyl-8-(trifluoromethyl)-2,3,4,4a,6,10b-hexahydro-lH-pyrano[3,2- b:5,4-b']dipyridine-l-carboxylate (1.2 g, 93%) as a yellow oil. MS ESI calculated for C18H23F3N2O3 [M+H]⁺, 373.17; found, 373.10. Step- 10:

A45 isomer 1

[1164] A mixture of tert-butyl (4aS,6R,10bS)-6-methyl-8-(trifluoromethyl)-2,3,4,4a,6,10b- hexahydro-lH-pyrano[3,2-b:5,4-b']dipyridine-l-carboxylate (1.10 g, 2.95 mmol) and HC1 (4M in 1,4-dioxane) (10 mL) was stirred at room temperature for 2 h. The mixture was concentrated under vacuum to afford (4aS,6R,10bS)-6-methyl-8-(trifluoromethyl)- 2,3,4,4a,6,10b-hexahydro-lH-pyrano[3,2-b:5,4-b']dipyridine hydrochloride (A45 isomer 1) (crude, 925 mg) as a white solid. MS ESI calculated for C13H15F3N2O [M+H]⁺, 273.11; found, 273.10. 'H NMR (400 MHz, DMSO) 8 10.66 (s, 1H), 8.80 (s, 1H), 8.44 (dd, J = 8.0, 3.0 Hz, 1H), 7.96 (d, J= 8.0 Hz, 1H), 4.99 - 4.92 (m, 1H), 4.53 (d, J= 10.4 Hz, 1H), 4.15 - 4.14 (m, 1H), 3.26 - 3.05 (m, 2H), 2.15 - 1.95 (m, 1H), 1.95 - 1.76 (m, 2H), 1.76 - 1.53 (m, 4H). The stereochemistry was determined by NOESY.

Intermediate A45 isomer 2: (4aS,6S,10bS)-6-methyl-8-(trifluoromethyl)-2,3,4,4a,6,10b- hexahydro- 1 H-pyrano [3 ,2-b : 5 ,4-b '] dipyridine

A45 isomer 2

Step-1: [1165] To a stirred solution of tert-butyl ((lS,2S)-5-((tert-butyldiphenylsilyl)oxy)-2- hydroxy-l-(2-((R)-l-hydroxyethyl)-6-(trifluoromethyl)pyridin-3-yl)pentyl)carbamate (8.4 g, 12.99 mmol) in toluene (100 mL) was added 2-(tributyl-X⁵-phosphaneylidene)acetonitrile (CAS No. 157141-27-0) (6.27 g, 25.97 mmol) at room temperature under nitrogen atmosphere. The resulting mixture was stirred at 100 °C for 16 h. The reaction mixture was concentrated under vacuum. The residue was purified by normal phase flash column chromatography with an 120 g silica gel column and eluted with 0-10% ethyl acetate in petroleum ether to afford tert-butyl ((5S,6S,8S)-6-(3-((tert-butyldiphenylsilyl)oxy)propyl)-8- methyl-2-(trifluoromethyl)-5,8-dihydro-6H-pyrano[3,4-b]pyridin-5-yl)carbamate (3.05 g, 37%) as a light yellow oil. MS ESI calculated for C34H43F3N2C>4Si [M+H]⁺, 629.29; found, 629.35.

Step-2:

[1166] To a stirred solution of tert-butyl ((5S,6S,8S)-6-(3-((tert- butyldiphenylsilyl)oxy)propyl)-8-methyl-2-(trifluoromethyl)-5,8-dihydro-6H-pyrano[3,4- b]pyridin-5-yl)carbamate (3.05 g, 4.85 mmol) in THF (30 mL) was added TBAF (1.52 g, 5.82 mmol) at room temperature. The mixture was stirred at room temperature for 16 h. The reaction mixture was concentrated under vacuum. The residue was purified by normal phase flash column chromatography with a 120 g silica gel column and eluted with 0-50% ethyl acetate in petroleum ether to afford tert-butyl ((5S,6S,8S)-6-(3-hydroxypropyl)-8-methyl-2- (trifluoromethyl)-5,8-dihydro-6H-pyrano[3,4-b]pyridin-5-yl)carbamate (1.3 g, 69%) as a light yellow oil. MS ESI calculated for C18H25F3N2O4 [M+H]⁺, 391.18; found, 391.25.

Step-3:

[1167] To a stirred solution of tert-butyl ((5S,6S,8S)-6-(3-hydroxypropyl)-8-methyl-2- (trifhioromethyl)-5,8-dihydro-6H-pyrano[3,4-b]pyridin-5-yl)carbamate (1.30 g, 3.33 mmol) in toluene (20 mL) was added 2-(tributyl ⁵-phosphaneylidene)acetonitrile (CAS No.

157141-27-0) (1.61 g, 6.66 mmol) at room temperature under nitrogen atmosphere. The mixture was stirred at 100 °C for 16 h. The reaction mixture was concentrated under vacuum. The residue was purified by normal phase flash column chromatography with an 80 g silica gel column and eluted with 0-20% ethyl acetate in petroleum ether to afford tert-butyl (4aS,6S,10bS)-6-methyl-8-(trifluoromethyl)-2,3,4,4a,6,10b-hexahydro-lH-pyrano[3,2-b:5,4- b']dipyridine-l -carboxylate (1.02 g, 82%) as a yellow oil. MS ESI calculated for C18H23F3N2O3 [M+H]⁺, 373.17; found, 373.10.

Step-4:

A45 isomer 2

[1168] A mixture of tert-butyl (4aS,6S,10bS)-6-methyl-8-(trifluoromethyl)-2,3,4,4a,6,10b- hexahydro-lH-pyrano[3,2-b:5,4-b']dipyridine-l-carboxylate (1.02 g, 2.74 mmol) and HC1 (4M in 1,4-dioxane) (10 mL) was stirred at room temperature for 2 h under nitrogen atmosphere. The mixture was concentrated under vacuum. The residue was purified by Prep- HPLC with the following conditions: [Column: XB ridge Prep OBD C18 Column30*150 mm; Mobile Phase A: Water (10 mmol/L NH4HCO3), Mobile Phase B: ACN; Flow rate: 60 mL/min; Gradient (B%): 5% B to 5% B in 2 min, 23% B to 43% B in 10 min; Wave Length: 254/220 nm; RTl(min): 8.9-9.4] to afford ((4aS,6S,10bS)-6-methyl-8-(trifhioromethyl)- 2,3,4,4a,6,10b-hexahydro-lH-pyrano[3,2-b:5,4-b']dipyridine (A45 isomer 2) (470 mg, 63%) as a white solid. MS ESI calculated for C13H15F3N2O [M+H]⁺, 273.11; found, 273.10. 'H NMR (400 MHz, DMSO) 5 8.04 (d, J = 7.6 Hz, 1H), 7.73 (dd, J = 8.0, 2.8 Hz, 1H), 5.12 - 34.93 (m, 1H), 4.08 - 3.88 (m, 1H), 3.76 (d, J = 2.8 Hz, 1H), 2.85 - 2.55 (m, 2H), 2.24 - 2.23 (m, 1H), 1.93 - 1.67 (m, 2H), 1.67 - 1.22 (m, 5H). The stereochemistry was determined by NOESY.

Intermediate A46 isomer 1: (4S,4aR,10bS)-4-fluoro-8-(trifluoromethyl)-2,3,4,4a,6,10b- hexahydro-lH-pyrano[3,2-b:5,4-b']dipyridine isomer 1

Step-1: '

[1169] To a stirred solution of propane- 1,3-diol (100.00 g, 1314.15 mmol) in DCM (200 mL) were added imidazole (223.66 g, 3285.37 mmol) and TBDPSC1 (397.33 g, 1445.56 mmol) at 0 °C. The resulting mixture was stirred at room temperature for 2 h. The resulting mixture was diluted with water. The resulting mixture was extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous NaiSCh. The resulting mixture was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with PE / EtOAc (0 - 10%) to afford 3-((tert- butyldiphenylsilyl)oxy)propan-l-ol (136.9 g, 33%) as a colorless oil. MS ESI calculated for C₁₉H₂₆O₂Si [M+H]⁺, 315.17; found, 315.15.

Step-2:

[1170] To a stirred solution of 3-((tert-butyldiphenylsilyl)oxy)propan-l-ol (40.00 g, 127.19 mmol) in DCM (400 mL) was added TEA (38.61 g, 381.56 mmol) at room temperature. To the above mixture was added a solution of Py-SO₃ (40.49 g, 254.37 mmol) in DMSO (200 mL) at 0°C. The resulting mixture was stirred at room temperature for additional 2 h. The resulting mixture was diluted with water. The resulting mixture was extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na₂SO4. The resulting mixture was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0 - 15% EtOAc in petroleum ether to afford 3-((tert- butyldiphenylsilyl)oxy)propanal (31.00 g, 78%) as a colorless oil. MS ESI calculated for Ci9H2₄O₂Si [M+H]⁺, 313.15; found, 313.15.

Step-3:

[1171] To a stirred solution of 3-((tert-butyldiphenylsilyl)oxy)propanal (31.00 g, 99.21 mmol) in THF (310 mL) was added Ethynyhnagnesium bromide (0.5 M solution in THF) (397 mL, 198.41 mmol) at 0 ° C dropwise under nitrogen atmosphere. The resulting mixture was stirred at room temperature for 2 h under nitrogen atmosphere. The reaction was quenched with NH4CI (sat.). The resulting mixture was extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SO4. The resulting mixture was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0 - 10% EtOAc in petroleum ether to afford a 1:1 mixture of (S)-5-((tert-butyldiphenylsilyl)oxy)pent-l-yn-3-ol and (R)-5-((tert- butyldiphenylsilyl)oxy)pent-l-yn-3-ol (19.20 g, 57%) as a yellow oil. MS ESI calculated for C2iH26O₂Si [M+H]⁺, 339.17; found, 339.10.

Step-4:

[1172] To a stirred solution of a 1:1 mixture of (S)-5-((tert-butyldiphenylsilyl)oxy)pent-l- yn-3-ol and (R)-5-((tert-butyldiphenylsilyl)oxy)pent-l-yn-3-ol (19.10 g, 56.42 mmol) in DCM (200 mL) were added imidazole (7.68 g, 112.84 mmol) and TBSC1 (10.20 g, 67.71 mmol) at 0 ° C. The resulting mixture was stirred at room temperature for 2 h. The resulting mixture was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0 - 5% EtOAc in petroleum ether to afford a 1:1 mixture of (S)-5-ethynyl-2,2,3,3, 10, 10-hexamethyl-9,9-diphenyl-4,8-dioxa-3,9- disilaundecane and (R)-5-ethynyl-2,2,3,3,10,10-hexamethyl-9,9-diphenyl-4,8-dioxa-3,9- disilaundecane (20.45 g, 80%) as a yellow oil. MS ESI calculated for C2?H4o02Si2 [M+H]⁺, 453.26; found, 453.25.

Step-5:

[1173] A mixture of 1:1 mixture of (S)-5-ethynyl-2,2,3,3,10,10-hexamethyl-9,9-diphenyl- 4,8-dioxa-3,9-disilaundecane and (R)-5-ethynyl-2,2,3,3,10,10-hexamethyl-9,9-diphenyl-4,8- dioxa-3,9-disilaundecane (20.00 g, 44.17 mmol), TEA (0.89 g, 8.83 mmol), Schwartz's reagent (2.27 g, 8.83 mmol) and HBpin (3.39 g, 26.50 mmol) was stirred at 60 °C for 4 h under nitrogen atmosphere. The resulting mixture was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0 - 40% DCM in petroleum ether to afford a 1:1 mixture of (R,E)-2,2,3,3,10,10-hexamethyl-9,9-diphenyl-5-(2- (4,4,5,5-tetramethyl-l ,3,2-dioxaborolan-2-yl)vinyl)-4,8-dioxa-3,9-disilaundecane and (S,E)- 2,2,3,3,10,10-hexamethyl-9,9-diphenyl-5-(2-(4,4,5,5-tetramethyl-l,3,2-dioxaborolan-2- yl)vinyl)-4,8-dioxa-3,9-disilaundecane (17.80 g, 69%) as a colorless oil. MS ESI calculated for C₃₃H53BO4Si2 [M+H]⁺, 581.36; found, 581.45.

Step-6:

[1174] To a stirred solution of 1: 1 mixture of (R,E)-2,2,3,3,10,10-hexamethyl-9,9- diphenyl-5-(2-(4,4,5,5-tetramethyl-l,3,2-dioxaborolan-2-yl)vinyl)-4,8-dioxa-3,9- disilaundecane and (S,E)-2,2,3,3,10,10-hexamethyl-9,9-diphenyl-5-(2-(4,4,5,5-tetramethyl- l,3,2-dioxaborolan-2-yl)vinyl)-4,8-dioxa-3,9-disilaundecane (15.30 g, 26.35 mmol) in 1,4- dioxane (140 mL) and H2O (14 mL) were added methyl 3-bromo-6- (trifluoromethyl)picolinate (6.80 g, 23.95 mmol), K2CO3 (9.93 g, 71.85 mmol) and Pd(dppf)Ch (1.75 g, 2.40 mmol) at room temperature. The resulting mixture was stirred at 80 °C for 16 h under nitrogen atmosphere. The resulting mixture was diluted with water and extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous NazSC . After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0 - 10% EtOAc in petroleum ether to afford a 1:1 mixture of methyl (S,E)-3-(3-((tert-butyldimethylsilyl)oxy)-5- ((tert-butyldiphenylsilyl)oxy)pent-l-en-l-yl)-6-(trifluoromethyl)picolinate and methyl (R,E)- 3-(3-((tert-butyldimethylsilyl)oxy)-5-((tert-butyldiphenylsilyl)oxy)pent-l-en-l-yl)-6- (trifhioromethyl)picolinate (14.20 g, 90%) as a yellow oil. MS ESI calculated for C₃5H46F₃NO4Si2 [M+H]⁺, 658.29; found, 658.30. NMR (400 MHz, DMSO-d₆) 5 8.38 (d, J = 8.4 Hz, 1H), 8.03 (d, J = 8.4 Hz, 1H), 7.63 - 7.56 (m, 4H), 7.47 - 7.36 (m, 6H), 6.89 (d, J = 15.6 Hz, 1H), 6.63 (dd, J = 16.0, 5.6 Hz, 1H), 4.64 - 4.59 (m, 1H), 3.88 (s, 3H), 3.82- 3.71 (m, 2H), 1.84 - 1.77 (m, 2H), 0.99 - 0.75 (m, 18H), 0.03 - 0.02 (m, 6H).

Step-7:

[1175] To a stirred solution of 1 : 1 mixture of methyl (S,E)-3-(3-((tert- butyldimethylsilyl)oxy)-5-((tert-butyldiphenylsilyl)oxy)pent- 1 -en- 1 -yl)-6- (trifhioromethyl)picolinate and methyl (R,E)-3-(3-((tert-butyldimethylsilyl)oxy)-5-((tert- butyldiphenylsilyl)oxy)pent-l-en-l-yl)-6-(trifluoromethyl)picolinate (14.20 g, 21.58 mmol) in THF (60 mL) were added AcOH (180 mL) and H2O (60 mL) at room temperature. The resulting mixture was stirred at room temperature for 32 h. The mixture was basified with saturated Na?CO₃ (sat.) to pH 8. The resulting mixture was extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SO4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0 - 30% EtOAc in petroleum ether to afford a 1:1 mixture of methyl (S,E)-3-(5-((tert-butyldiphenylsilyl)oxy)-3-hydroxypent-l-en-l-yl)-6- (trifhioromethyl)picolinate and methyl (R,E)-3-(5-((tert-butyldiphenylsilyl)oxy)-3- hydroxypent-l-en-l-yl)-6-(trifluoromethyl)picolinate (6.57 g, 56%) as a yellow oil. MS ESI calculated for C29H₃₂F₃NO₄Si [M+H]⁺, 544.21; found, 544.25.

Step-8:

[1176] To a stirred solution of 1: 1 mixture of methyl (S,E)-3-(5-((tert- butyldiphenylsilyl)oxy)-3-hydroxypent-l-en-l-yl)-6-(trifluoromethyl)picolinate and methyl (R,E)-3-(5-((tert-butyldiphenylsilyl)oxy)-3-hydroxypent-l-en-l-yl)-6-

(trifhioromethyl)picolinate (6.57 g, 12.09 mmol) in DCM (70 mL) was added DAST (3.90 g, 24.17 mmol) at 0 °C. The resulting mixture was stirred at room temperature for 2 h. The reaction was quenched with ice water. The resulting mixture was extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous NaiSCL. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0 - 10% EtOAc in petroleum ether to afford a 1:1 mixture of methyl (S,E)-3-(5-((tert-butyldiphenylsilyl)oxy)-3-fluoropent-l-en-l-yl)-6- (trifluoromethyl)picolinate and methyl (R,E)-3-(5-((tert-butyldiphenylsilyl)oxy)-3- fluoropent-l-en-l-yl)-6-(trifluoromethyl)picolinate (4.78 g, 72%) as a colorless oil. MS ESI calculated for C2₉H₃iF₄NO₃Si [M+H]⁺, 546.20; found, 546.25. 'H NMR (400 MHz, DMSO- d₆) 38.45 (d, J= 8.4 Hz, 1H), 8.10 (d, J= 8.4 Hz, 1H), 7.65 - 7.61 (m, 4H), 7.49 - 7.38 (m, 6H), 7.11 (d, J = 16.0 Hz, 1H), 6.75 - 6.64 (m, 1H), 5.53 - 5.34 (m, 1H), 3.91 (s, 3H), 3.87 - 3.76 (m, 2H), 2.09 - 1.98 (m, 2H), 1.01 - 0.99 (m, 9H).

Step-9:

[1177] A mixture of BocNH₂(2.52 g, 21.48 mmol, 0.8 M in n-PrOH) and NaOH (0.75 g, 18.71 mmol, 0.8M) was stirred at 0 °C for 10 min. Then DCDMH (2.05 g, 10.39 mmol) was added to the mixture at 0 °C. After stirring for 30 min. This was followed by the addition of (DHQ)2PHAL (supplier: Shanghai Accela ChemBio Co., Ltd. CAS# 140924-50-1) (0.54 g, 0.69 mmol, 0.1 M in n-PrOH), a solution of 1:1 mixture of methyl (S,E)-3-(5-((tert- butyldiphenylsilyl)oxy)-3-fhioropent- 1 -en- 1 -yl)-6-(trifhioromethyl)picolinate and methyl (R,E)-3-(5-((tert-butyldiphenylsilyl)oxy)-3-fluoropent-l-en-l-yl)-6- (trifluoromethyl)picolinate (3.78 g, 6.93 mmol) in n-PrOH(30 mL) and K2OSO4.2H2O (0.26 g, 0.69 mmol) at 0 °C. The resulting mixture was stirred at room temperature for 16 h. The resulting mixture was diluted with water and extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SC>4. After filtration, the filtrate was concentrated under reduced pressure.

[1178] The residue was dissolved in DCM (40 mL), then DMAP (0.19 g, 1.55 mmol) and DCC (3.21 g, 15.54 mmol) were added at room temperature. The resulting mixture was stirred at room temperature for 2 h. The resulting mixture was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0 30% EtOAc in petroleum ether to afford a 1:1 mixture of tert-butyl ((5S,6R)-6-((S)-3-((tert- butyldiphenylsilyl)oxy)-l-fhioropropyl)-8-oxo-2-(trifluoromethyl)-5,8-dihydro-6H- pyrano[3,4-b]pyridin-5-yl)carbamate and tert-butyl ((5S,6R)-6-((S)-3-((tert- butyldiphenylsilyl)oxy)-l-fhioropropyl)-8-oxo-2-(trifhioromethyl)-5,8-dihydro-6H- pyrano[3,4-b]pyridin-5-yl)carbamate (2.10 g, 43%) as a yellow solid. MS ESI calculated for C33H₃8F₄N2O5Si [M+H]⁺, 647.25; found, 647.30.

Step- 10:

[1179] To a stirred solution of 1: 1 mixture of tert-butyl ((5S,6R)-6-((S)-3-((tert- butyldiphenylsilyl)oxy)-l-fluoropropyl)-8-oxo-2-(trifluoromethyl)-5,8-dihydro-6H- pyrano[3,4-b]pyridin-5-yl)carbamate and tert-butyl ((5S,6R)-6-((S)-3-((tert- butyldiphenylsilyl)oxy)-l-fluoropropyl)-8-oxo-2-(trifluoromethyl)-5,8-dihydro-6H- pyrano[3,4-b]pyridin-5-yl)carbamate (2.10 g, 3.25 mmol) in THF (20 mL) was added NaBFL (0.25 g, 6.49 mmol) in portions at 0 °C. The resulting mixture was stirred at 0°C for 2 h. The reaction was quenched with ice water at 0 °C. The resulting mixture was extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SO₄. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0 ~ 30% EtOAc in petroleum ether to afford tert-butyl ((lS,2R,3S)-5-((tert-butyldiphenylsilyl)oxy)-3-fluoro-2-hydroxy-l-(2- (hydroxymethyl)-6-(trifhioromethyl)pyridin-3-yl)pentyl)carbamate (720 mg, 34%) as a colorless oil with first eluting peak on column purification. MS ESI calculated for C₃3H42F₄N2O5Si [M+H]⁺, 651.28; found, 651.30.

[1180] The purification also afforded tert-butyl ((lS,2R,3R)-5-((tert- butyldiphenylsilyl)oxy)-3-fluoro-2-hydroxy- 1 -(2-(hydroxymethyl)-6- (trifhioromethyl)pyridin-3-yl)pentyl)carbamate (700 mg, 33%) as a colorless oil with the second eluting peak on column purification. MS ESI calculated for CssF E ^OsSi [M+H]⁺, 651.28; found, 651.30.

Step-11:

[1181] To a solution of tert-butyl ((lS,2R,3S)-5-((tert-butyldiphenylsilyl)oxy)-3-fluoro-2- hydroxy-l-(2-(hydroxymethyl)-6-(trifluoromethyl)pyridin-3-yl)pentyl)carbamate (720 mg, 1.11 mmol) in toluene (8 mL) was added 2-(tributyl-X⁵-phosphaneylidene)acetonitrile (CAS No. 157141-27-0) (534 mg, 2.21 mmol). The resulting mixture was stirred at 110 °C for 16 h under nitrogen atmosphere. The resulting mixture was concentrated under vacuum. The residue was purified by silica gel column chromatography, eluted with 0 ~ 20% EtOAc in petroleum ether to afford tert-butyl ((5S,6R)-6-((S)-3-((tert-butyldiphenylsilyl)oxy)-l- fhioropropyl)-2-(trifluoromethyl)-5,8-dihydro-6H-pyrano[3,4-b]pyridin-5-yl)carbamate (500 mg, 71%) as a yellow oil. MS ESI calculated for C33H4oF4N204Si [M+H]⁺, 633.27; found, 633.30.

[1182] To a solution of tert-butyl ((5S,6R)-6-((S)-3-((tert-butyldiphenylsilyl)oxy)-l- fluoropropyl)-2-(trifluoromethyl)-5,8-dihydro-6H-pyrano[3,4-b]pyridin-5-yl)carbamate (500 mg, 0.79 mmol) in THF (5 mL) was added TBAF (499 mg, 1.58 mmol). The resulting mixture was stirred at room temperature for 1 h. The resulting mixture was concentrated under vacuum. The residue was purified by silica gel column chromatography, eluted with 0 ~ 50% EtOAc in petroleum ether to afford tert-butyl ((5S,6R)-6-((S)-l-fhioro-3- hydroxypropyl)-2-(trifluoromethyl)-5,8-dihydro-6H-pyrano[3,4-b]pyridin-5-yl)carbamate (180 mg, 58%) as a white solid. MS ESI calculated for C17H22F4N2O4 [M+H]⁺, 395.15; found, 395.15.

Step-13:

[1183] To a stirred solution of tert-butyl ((5S,6R)-6-((S)-l-fluoro-3-hydroxypropyl)-2- (trifhioromethyl)-5,8-dihydro-6H-pyrano[3,4-b]pyridin-5-yl)carbamate (180 mg, 0.46 mmol) in Toluene (1.8 mL) was added 2-(tributyl-X⁵-phosphaneylidene)acetonitrile (CAS No. 157141-27-0) (220 mg, 0.91 mmol). The resulting mixture was stirred at 110 °C for 16 h under nitrogen atmosphere. The resulting mixture was concentrated under vacuum. The residue was purified by silica gel column chromatography, eluted with 0 ~ 20% EtOAc in petroleum ether to afford tert-butyl (4S,4aR,10bS)-4-fhioro-8-(trifluoromethyl)- 2,3,4,4a,6,10b-hexahydro-lH-pyrano[3,2-b:5,4-b']dipyridine-l-carboxylate (129 mg, 75%) as a yellow oil. MS ESI calculated for C17H20F4N2O3 [M+H]⁺, 377.14; found, 377.15. ¹H NMR (400 MHz, DMSO-d₆) 8 7.84 (d, J = 8.4 Hz, 1H), 7.71 (d, J = 8.0 Hz, 1H), 5.43 (d, J = 6.8Hz, 1H), 5.26 - 5.11 (m, 1H), 5.05 - 4.87 (m, 2H), 4.35 - 4.22 (m, 1H), 3.89 - 3.80 (m, 1H), 2.77 - 2.70 (m, 1H), 1.96 - 1.81 (m, 2H), 1.46 (s, 9H). The stereochemistry was determined by NOESY.

Step- 14:

[1184] A mixture of tert-butyl (4S,4aR,10bS)-4-fluoro-8-(trifluoromethyl)-2,3,4,4a,6,10b- hexahydro-lH-pyrano[3,2-b:5,4-b']dipyridine-l-carboxylate (129 mg, 0.34 mmol) and HCl (4.0 M in 1,4-dioxane) (1 mL) was stirred at 0 °C for 1 h. The resulting mixture was concentrated under reduced pressure to afford (4S,4aR,10bS)-4-fluoro-8-(trifluoromethyl)- 2,3,4,4a,6,10b-hexahydro-lH-pyrano[3,2-b:5,4-b']dipyridine hydrochloride (A46 isomer 1) (100 mg, crude) as a white solid. MS ESI calculated for C12H12F4N2O [M+H]⁺, 277.09; found, 277.15. 'H NMR (400 MHz, DMSO-J₆) 3 10.89 (s, 1H), 9.08 (s, 1H), 8.44 (d, J = 8.0 Hz, 1H), 7.98 (d, J = 8.0 Hz, 1H), 5.18 - 4.91 (m, 3H), 4.67 - 4.66 (m, 1H), 4.48 - 4.45 (m, 1H), 3.42 - 3.10 (m, 2H), 2.14 - 2.11 (m, 2H). The stereochemistry was determined by NOESY.

Intermediate A46 isomer 2: (4R,4aR,10bS)-4-fluoro-8-(trifluoromethyl)-2,3,4,4a,6,10b- hexahydro- 1 H-pyrano [3 ,2-b : 5 ,4-b '] dipyridine

A46 isomer 2

Step-1:

[1185] To a solution of tert-butyl ((lS,2R,3R)-5-((tert-butyldiphenylsilyl)oxy)-3-fluoro-2- hydroxy-l-(2-(hydroxymethyl)-6-(trifluoromethyl)pyridin-3-yl)pentyl)carbamate (700 mg, 1.08 mmol) in toluene (8 mL) was added 2-(tributyl-X⁵-phosphaneylidene)acetonitrile (CAS No. 157141-27-0) (519 mg, 2.15 mmol). The resulting mixture was stirred at 110 °C for 16 h under nitrogen atmosphere. The resulting mixture was concentrated under vacuum. The residue was purified by silica gel column chromatography, eluted with 0 ~ 20% EtOAc in petroleum ether to afford tert-butyl ((5S,6R)-6-((R)-3-((tert-butyldiphenylsilyl)oxy)-l- fluoropropyl)-2-(trifluoromethyl)-5,8-dihydro-6H-pyrano[3,4-b]pyridin-5-yl)carbamate (428 mg, 63%) as a yellow oil. MS ESI calculated for C33H4oF4N204Si [M+H]⁺, 633.27; found, 633.30.

Step-2:

[1186] To a solution of tert-butyl ((5S,6R)-6-((R)-3-((tert-butyldiphenylsilyl)oxy)-l- fluoropropyl)-2-(trifluoromethyl)-5,8-dihydro-6H-pyrano[3,4-b]pyridin-5-yl)carbamate (420 mg, 0.66 mmol) in THF (5 mL) was added TBAF (419 mg, 1.33 mmol). The resulting mixture was stirred at room temperature for 1 h. The resulting mixture was concentrated under vacuum. The residue was purified by silica gel column chromatography, eluted with 0 ~ 50% EtOAc in petroleum ether to afford tert-butyl ((5S,6R)-6-((R)-l-fluoro-3- hydroxypropyl)-2-(trifluoromethyl)-5,8-dihydro-6H-pyrano[3,4-b]pyridin-5-yl)carbamate (150 mg, 57%) as a white solid. MS ESI calculated for C17H22F4N2O4 [M+H]⁺, 395.15; found, 395.10.

Step-3:

[1187] To a stirred solution of tert-butyl ((5S,6R)-6-((R)-l-fluoro-3-hydroxypropyl)-2- (trifhioromethyl)-5,8-dihydro-6H-pyrano[3,4-b]pyridin-5-yl)carbamate (150 mg, 0.41 mmol) in Toluene (1.6 mL) was added 2-(tributyl- ⁵-phosphaneylidene)acetonitrile (CAS No. 157141-27-0) (196 mg, 0.81 mmol). The resulting mixture was stirred at 110 °C for 16 h under nitrogen atmosphere. The resulting mixture was concentrated under vacuum. The residue was purified by silica gel column chromatography, eluted with 0 ~ 20% EtOAc in petroleum ether to afford tert-butyl (4R,4aR,10bS)-4-fhioro-8-(trifluoromethyl)- 2,3,4,4a,6,10b-hexahydro-lH-pyrano[3,2-b:5,4-b']dipyridine-l-carboxylate (117 mg, 77%) as a yellow oil. MS ESI calculated for C17H20F4N2O3 [M+H]⁺, 377.14; found, 377.15. 'H NMR (400 MHz, DMSO-rfe) 87.87 (d, J= 8.0 Hz, 1H), 7.68 (d, J= 8.0 Hz, 1H), 5.61 - 5.59 (m, 1H), 5.04 - 4.84 (m, 3H), 4.24 - 4.17 (m, 1H), 3.96 - 3.92 (m, 1H), 2.05 - 1.99 (m, 1H), 1.70 - 1.69 (m, 2H), 1.46 (s, 9H). The stereochemistry was determined by NOESY.

Step-4:

[1188] A mixture of tert-butyl (4R,4aR,10bS)-4-fluoro-8-(trifluoromethyl)-2,3,4,4a,6,10b- hexahydro-lH-pyrano[3,2-b:5,4-b']dipyridine-l-carboxylate (117 mg, 0.31 mmol) and HCl (4.0 M in 1,4-dioxane) (1 mL) was stirred at 0 °C for 1 h. The resulting mixture was concentrated under reduced pressure to afford (4R,4aR,10bS)-4-fluoro-8-(trifluoromethyl)- 2,3,4,4a,6,10b-hexahydro-lH-pyrano[3,2-b:5,4-b']dipyridine hydrochloride (A46 isomer 2) (100 mg, crude) as a white solid. MS ESI calculated for C12H12F4N2O [M+H]⁺, 277.09; found, 277.15. 'H NMR (400 MHz, DMSO) 8 10.71 (br, 1H), 9.28 (br, 1H), 8.49 - 8.46 (m, 1H), 8.01 (d, J= 8.0 Hz, 1H), 5.18 - 4.98 (m, 3H), 4.74 (s, 1H), 4.39 - 4.33 (m, 1H), 3.27 -

3.14 (m, 2H), 2.17 - 1.92 (m, 2H). The stereochemistry was determined by NOESY.

Intermediate A47 isomer 1: (4S,4aR,10bS)-8-chloro-4-fluoro-2,3,4,4a,6,10b-hexahydro- 1 H-pyrano [3 ,2-b : 5 ,4-b'] dipyridine

A47 isomer 1 . _an(

Intermediate A47 isomer 2: (4R,4aR,10bS)-8-chloro-4-fluoro-2,3,4,4a,6,10b-hexahydro-

1 H-pyrano [3 ,2-b : 5 ,4-b'] dipyridine

A47 isomer 2

Step-1:

[1189] To a stirred mixture of 3-bromo-6-chloropicolinic acid (50 g, 211.46 mmol) and K2CO3 (58.45 g, 422.92 mmol) in DMF (500 mL) was added Mel (33.02 g, 232.61 mmol) dropwise at 0 °C. The resulting mixture was stirred at room temperature for 16 h. The resulting mixture was diluted with water. The resulting mixture was extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SO4. After filtration, the filtrate was concentrated under reduced pressure to afford methyl 3-bromo-6- chloropicolinate (45.8 g, crude) as a yellow solid. MS ESI calculated for CyHsBrQNCh [M+H]⁺, 249.92, 251.92; found, 249.90, 251.90. Step-2:

[1190] To a stirred solution of methyl 3-bromo-6-chloropicolinate (25 g, 99.81 mmol) and a 1:1 mixture of (R,E)-2,2,3,3,l0,10-hexamethyl-9,9-diphenyl-5-(2-(4,4,5,5-tetramethyl- 1 ,3,2-dioxaborolan-2-yl)vinyl)-4,8-dioxa-3,9-disilaundecane and (S,E)-2,2,3,3, 10, 10- hexamethyl-9,9-diphenyl-5-(2-(4,4,5,5-tetramethyl-l,3,2-dioxaborolan-2-yl)vinyl)-4,8-dioxa- 3,9-disilaundecane (57.96 g, 99.81 mmol) in 1,4-Dioxane (250 mL) and H2O (25 mL) were added Pd(dppf)Cl₂-CH₂C12 (8.15 g, 9.98 mmol) and K₂CO₃ (41.38 g, 299.42 mmol). The resulting mixture was stirred at 80 °C for 4 h under nitrogen atmosphere. The resulting mixture was diluted with water and extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na₂SO4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with PE/EtOAc (10:1) to afford a 1:1 mixture of methyl (S,E)-3-(3- ((tert-butyldimethylsilyl)oxy)-5-((tert-butyldiphenylsilyl)oxy)pent-l-en-l-yl)-6- chloropicolinate and methyl (R,E)-3-(3-((tert-butyldimethylsilyl)oxy)-5-((tert- butyldiphenylsilyl)oxy)pent-l-en-l-yl)-6-chloropicolinate (42.7 g, 68%) as a yellow oil. MS ESI calculated for C₃4H4eClNO4Si₂ [M+H]⁺, 624.27; found, 624.25.

Step-3:

[1191] To a stirred solution of 1 : 1 mixture of methyl (S,E)-3-(3-((tert- butyldimethylsilyl)oxy)-5-((tert-butyldiphenylsilyl)oxy)pent- 1 -en- 1 -yl)-6-chloropicolinate and methyl (R,E)-3-(3-((tert-butyldimethylsilyl)oxy)-5-((tert-butyldiphenylsilyl)oxy)pent- 1 - en-l-yl)-6-chloropicolinate (42 g, 67.27 mmol) in THF (168 mL) were added AcOH (504 mL) and H₂O (168 mL) at room temperature. The resulting mixture was stirred at room temperature for 48 h. The resulting mixture was concentrated under reduced pressure. The mixture was basified with Na₂CO₃ (sat.) to pH 7. The resulting mixture was extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SO4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with PE/EtOAc (5:1) to afford a 1:1 mixture of methyl (S,E)-3-(5-((tert-butyldiphenylsilyl)oxy)-3-hydroxypent- 1-en- 1 -yl)-6-chloropicolinate and methyl (R,E)-3-(5-((tert-butyldiphenylsilyl)oxy)-3-hydroxypent-l-en-l-yl)-6- chloropicolinate (22 g, 64%) as a yellow oil. MS ESI calculated for C2«H32ClNO4Si [M+H]⁺, 510.18; found, 510.15.

Step-4:

[1192] To a stirred solution of 1: 1 mixture of methyl (S,E)-3-(5-((tert- butyldiphenylsilyl)oxy)-3-hydroxypent-l-en-l-yl)-6-chloropicolinate and methyl (R,E)-3-(5- ((tert-butyldiphenylsilyl)oxy)-3-hydroxypent-l-en-l-yl)-6-chloropicolinate (22 g, 43.13 mmol) in THF (220 mL) was added DAST (13.90 g, 86.26 mmol) dropwise at 0 °C. The resulting mixture was stirred at 0 °C for 1 h. The reaction was quenched with ice water at 0 °C. The resulting mixture was extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous NajSC . After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with PE/EtOAc (10:1) to afford a 1:1 mixture of methyl (S,E)-3-(5- ((tert-butyldiphenylsilyl)oxy)-3-fhioropent-l-en-l-yl)-6-chloropicolinate and methyl (R,E)-3- (5-((tert-butyldiphenylsilyl)oxy)-3-fluoropent-l-en-l-yl)-6-chloropicolinate (12.4 g, 56%) as a yellow oil. MS ESI calculated for C28H3iClFNO₃Si [M+H]⁺, 512.17; found, 512.15. 'H NMR (400 MHz, DMSO-d₆) 8 8.23 (d, J = 8.4 Hz, 1H), 7.74 (d, J = 8.4 Hz, 1H), 7.64 - 7.60 (m, 4H), 7.48 - 7.39 (m, 6H), 7.11 - 7.06 (m, 1H), 6.63 - 6.54 (m, 1H), 5.47 - 5.33 (m, 1H), 3.88 (s, 3H), 3.84 - 3.74 (m, 2H), 2.07 - 1.96 (m, 2H), 1.00 (s, 9H).

Step-5: [1193] To a solution of B0CNH2 (8.79 g, 75.06 mmol) in n-PrOH (90 mL) was added a solution of NaOH (2.61 g, 65.38 mmol) in water (80 mL) at 0 °C. After stirring at 0 °C for 10 minutes, DCDMH (7.16 g, 36.32 mmol) was added in portions at 0 °C. The mixture was stirred at 0 °C for 30 minutes. This was followed by the addition of a solution of (DHQ)2PHAL (supplier: Shanghai Accela ChemBio Co., Ltd. CAS# 140924-50-1) (1.89 g, 2.42 mmol) in n-PrOH (24 mL), a solution of 1:1 mixture of methyl (S,E)-3-(5-((tert- butyldiphenylsilyl)oxy)-3-fluoropent-l-en-l-yl)-6-chloropicolinate and methyl (R,E)-3-(5- ((tert-butyldiphenylsilyl)oxy)-3-fluoropent-l-en-l-yl)-6-chloropicolinate (12.4 g, 24.21 mmol) in n-PrOH(50 mL) and K2OSO4.2H2O (0.89 g, 2.42 mmol) at 0 °C. The resulting mixture was stirred at 0 °C for 4 h. The resulting mixture was diluted with water and extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SO4. After filtration, the filtrate was concentrated under reduced pressure. The residue was dissolved with DCM (140 mL), then DCC (9.15 g, 44.36 mmol) and DMAP (0.54 g, 4.43 mmol) were added to the mixture at 0 °C. The resulting mixture was stirred at 25 °C for 1 h. The resulting mixture was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with PE/EtOAc (1:1) to afford a 1:1 mixture of tert-butyl ((5S,6R)-6-((S)-3-((tert-butyldiphenylsilyl)oxy)-l-fluoropropyl)-2- chloro-8-oxo-5,8-dihydro-6H-pyrano[3,4-b]pyridin-5-yl)carbamate and tert-butyl ((5S,6R)-6- ((R)-3-((tert-butyldiphenylsilyl)oxy)-l-fluoropropyl)-2-chloro-8-oxo-5,8-dihydro-6H- pyrano[3,4-b]pyridin-5-yl)carbamate (9.6 g, 35%) as a white solid. MS ESI calculated for C32H₃8ClFN2O₅Si [M+H]⁺, 613.22; found, 613.25.

Step-6:

[1194] To a stirred solution of 1 : 1 mixture of tert-butyl ((5S,6R)-6-((S)-3-((tert- butyldiphenylsilyl)oxy)-l-fluoropropyl)-2-chloro-8-oxo-5,8-dihydro-6H-pyrano[3,4- b]pyridin-5-yl)carbamate and tert-butyl ((5S,6R)-6-((R)-3-((tert-butyldiphenylsilyl)oxy)-l- fluoropropyl)-2-chloro-8-oxo-5,8-dihydro-6H-pyrano[3,4-b]pyridin-5-yl)carbamate (9.6 g, 15.65 mmol) in THF (100 mL) was added NaBH4 (1.18 g, 31.31 mmol) in portions at 0°C. The resulting mixture was stirred at 0 °C for 1 h. The reaction was quenched with ice water at 0 °C. The resulting mixture was extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na₂SC>4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with PE/EtOAc (4:1) to afford a 1:1 mixture of tert-butyl ((lS,2R,3S)-5-((tert-butyldiphenylsilyl)oxy)-l-(6-chloro-2-(hydroxymethyl)pyridin-3-yl)-3- fhioro-2-hydroxypentyl)carbamate and tert-butyl ((lS,2R,3R)-5-((tert- butyldiphenylsilyl)oxy)-l-(6-chloro-2-(hydroxymethyl)pyridin-3-yl)-3-fluoro-2- hydroxypentyl)carbamate (6.3 g, 65%) as a white solid. MS ESI calculated for C₃₂H₄₂ClFN₂O₅Si [M+H]⁺, 617.25; found, 617.25.

Step-7:

[1195] To a stirred solution of 1 : 1 mixture of tert-butyl ((lS,2R,3S)-5-((tert- butyldiphenylsilyl)oxy)-l-(6-chloro-2-(hydroxymethyl)pyridin-3-yl)-3-fluoro-2- hydroxypentyl)carbamate and tert-butyl ((lS,2R,3R)-5-((tert-butyldiphenylsilyl)oxy)-l-(6- chloro-2-(hydroxymethyl)pyridin-3-yl)-3-fluoro-2-hydroxypentyl)carbamate (6.3 g, 10.21 mmol) in toluene (63 mL) was added 2-(tributyl-X⁵-phosphaneylidene)acetonitrile (CAS No. 157141-27-0) (4.93 g, 20.41 mmol) at room temperature. The resulting mixture was stirred at 110 °C for 16 h. The resulting mixture was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with PE/EtOAc (5:1) to afford a 1:1 mixture of tert-butyl ((5S,6R)-6-((S)-3-((tert-butyldiphenylsilyl)oxy)-l-fluoropropyl)-2- chloro-5,8-dihydro-6H-pyrano[3,4-b]pyridin-5-yl)carbamate and tert-butyl ((5S,6R)-6-((R)- 3-((tert-butyldiphenylsilyl)oxy)-l-fluoropropyl)-2-chloro-5,8-dihydro-6H-pyrano[3,4- b]pyridin-5-yl)carbamate (870 mg, 14%) as a yellow oil. MS ESI calculated for C₃₂H4oClFN₂0₄Si [M+H]⁺, 599.24; found, 599.25.

Step-8: [1196] To a stirred solution of 1: 1 mixture of tert-butyl ((5S,6R)-6-((S)-3-((tert- butyldiphenylsilyl)oxy)-l-fluoropropyl)-2-chloro-5,8-dihydro-6H-pyrano[3,4-b]pyridin-5- yl)carbamate and tert-butyl ((5S,6R)-6-((R)-3-((tert-butyldiphenylsilyl)oxy)-l-fhioropropyl)- 2-chloro-5,8-dihydro-6H-pyrano[3,4-b]pyridin-5-yl)carbamate (870 mg, 1.45 mmol) in THF (10 mL) was added TBAF (759 mg, 2.90 mmol) in portions at room temperature. The resulting mixture was stirred at 25 °C for 3 h. The resulting mixture was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with PE/EtOAc (1:1) to afford a 1:1 mixture of tert-butyl ((5S,6R)-2-chloro-6-((S)-l-fhioro-3- hydroxypropyl)-5,8-dihydro-6H-pyrano[3,4-b]pyridin-5-yl)carbamate and tert-butyl ((5S,6R)-2-chloro-6-((R)-l-fluoro-3-hydroxypropyl)-5,8-dihydro-6H-pyrano[3,4-b]pyridin-5- yl)carbamate (500 mg, 95%) as a yellow oil. MS ESI calculated for C16H22CIFN2O4 [M+H]⁺, 361.13; found, 361.10.

[1197] To a stirred solution of 1: 1 mixture of tert-butyl ((5S,6R)-2-chloro-6-((S)-l-fluoro- 3-hydroxypropyl)-5,8-dihydro-6H-pyrano[3,4-b]pyridin-5-yl)carbamate and tert-butyl ((5S,6R)-2-chloro-6-((R)-l-fluoro-3-hydroxypropyl)-5,8-dihydro-6H-pyrano[3,4-b]pyridin-5- yl)carbamate (500 mg, 1.38 mmol) in toluene (5 mL) was added 2-(tributyl-X⁵- phosphaneylidene)acetonitrile (CAS No. 157141-27-0) (669 mg, 2.77 mmol) at room temperature. The resulting mixture was stirred at 110 °C for 16 h. The resulting mixture was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with PE/EtOAc (5:1) to afford a 1:1 mixture of tert-butyl (4S,4aR,10bS)-8-chloro-4-fluoro-2,3,4,4a,6,10b-hexahydro-lH-pyrano[3,2-b:5,4- b']dipyridine-l -carboxylate and tert-butyl (4R,4aR,10bS)-8-chloro-4-fluoro-2,3,4,4a,6,10b- hexahydro-lH-pyrano[3,2-b:5,4-b']dipyridine-l-carboxylate (400 mg, 84%) as a colorless oil. MS ESI calculated for C16H20CIFN2O3 [M+H]⁺, 343.11; found, 343.10.

Step- 10:

[1198] A solution of 1:1 mixture of tert-butyl (4S,4aR,10bS)-8-chloro-4-fluoro-

2,3 ,4, 4a, 6, 1 Ob-hexahydro- IH-pyrano [ ,2-b:5 ,4-b'] dipyridine- 1 -carboxylate and tert-butyl (4R,4aR,10bS)-8-chloro-4-fluoro-2,3,4,4a,6,10b-hexahydro-lH-pyrano[3,2-b:5,4- b']dipyridine-l -carboxylate (400 mg, 0.67 mmol) and HC1 (4M in 1,4-dioxane) (2 mL) was stirred at 25 °C for 1 h. The resulting mixture was concentrated under reduced pressure to afford a 1:1 mixture of (4S,4aR,10bS)-8-chloro-4-fluoro-2,3,4,4a,6,10b-hexahydro-lH- pyrano[3,2-b:5,4-b']dipyridine and (4R,4aR,10bS)-8-chloro-4-fluoro-2,3,4,4a,6,10b- hexahydro-lH-pyrano[3,2-b:5,4-b']dipyridine hydrochloride (A25) (400 mg, crude) as a white solid. MS ESI calculated for C11H12CIFN2O [M+H]⁺, 243.06; found, 243.00.

Step-11:

A47 isomer 2

[1199] The intermediate A47 (400 mg) was purification by Perp-Chiral HPLC with the following conditions (Column: CHIRAL ART Cellulose-SC, 2*25 cm, 5 pm; Mobile Phase A: Hex (0.5% 2M NH₃-MeOH)-HPLC, Mobile Phase B: ETOH: DCM=1:1-HPLC; Flow rate: 20 mL/min; Gradient (B%): isocratic 10% B to 10% in 16min; Wave Length: 220/254 nm; RTl(min): 8.89; RT2(min): 12.61; Sample Solvent: MeOH: DCM=1:1-HPLC) to afford (4R,4aR,10bS)-8-chloro-4-fluoro-2,3,4,4a,6,10b-hexahydro-lH-pyrano[3,2-b:5,4- b']dipyridine (A47 isomer 2) (90 mg, 22%) as a yellow oil with retention time at 8.89 minutes. MS ESI calculated for C11H12CIFN2O [M+H]⁺, 243.06; found, 243.00. ^JH NMR (400 MHz, DMSO-de) 57.88 (d, J= 8.4 Hz, 1H), 7.42 (d, J= 8.0 Hz, 1H), 5.00 - 4.71 (m, 3H), 3.93 - 3.92 (m, 1H), 3.85 - 3.81 (m, 1H), 2.91 - 2.84 (m, 1H), 2.74 - 2.69 (m, 1H), 1.92 - 1.70 (m, 2H). The stereochemistry was determined by NOESY.

[1200] The chiral resolution also afforded (4S,4aR,10bS)-8-chloro-4-fluoro-2,3,4,4a,6,10b- hexahydro-lH-pyrano[3,2-b:5,4-b']dipyridine (A47 isomer 1) (140 mg, 35%) as a yellow solid with retention time at 12.61 minutes. MS ESI calculated for C11H12CIFN2O [M+H]⁺, 243.06; found, 243.00. 'H NMR (400 MHz, DMSO-d₆) 87.79 (d, J= 8.0 Hz, 1H), 7.39 (d, J = 8.0 Hz, 1H), 4.92 - 4.67 (m, 3H), 3.99 - 3.96 (m, 1H), 3.67 - 3.66 (m, 1H), 3.05 - 2.98 (m, 1H), 2.70 - 2.61 (m, 1H), 1.84 - 1.75 (m, 2H). The stereochemistry was determined by NOESY.

Intermediate A48: (2R,4aS,10bS)-2-methyl-8-(trifluoromethyl)-l,2,3,4a,5,10b- hexahydrochromeno[3,4-b] [ 1 ,4]oxazine

[1201] To a mixture of a 1:1 mixture of (3S,4S)-4-amino-7-(trifluoromethyl)chroman-3-ol and (3R,4R)-4-amino-7-(trifluoromethyl)chroman-3-ol (13.0 g, 55.74 mmol) (From A4) in MeOH (130 mL) was added TEA (11.3 g, 111.47 mmol) and Boc₂O (13.38 g, 61.32 mmol) at 0 °C. The mixture was stirred at 25 °C for 2 h. The resulting mixture was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with PE in EtOAc (0-80%) to afford a 1:1 mixture of tert-butyl ((3S,4S)-3-hydroxy-7- (trifhioromethyl)chroman-4-yl)carbamate and tert-butyl ((3R,4R)-3-hydroxy-7- (trifhioromethyl)chroman-4-yl)carbamate (6.5 g, 35 %) as a yellow solid. MS ESI calculated for C15H18F3NO4 [M+H]⁺, 334.12; found, 278.05 [M-C₄H₈+H]⁺.

Step-2:

[1202] To a mixture of a 1: 1 mixture of tert-butyl ((3S,4S)-3-hydroxy-7- (trifluoromethyl)chroman-4-yl)carbamate and tert-butyl ((3R,4R)-3-hydroxy-7- (trifluoromethyl)chroman-4-yl)carbamate (5.1 g, 15.00 mmol), tetrabutylazanium hydrogen sulfate (1.02 g, 3.00 mmol) and NaOH (4.20 g, 105.00 mmol) in DCM (50 mL) was added (4S)-4-methyl-l, 3, 2-A,-6-dioxathiolane-2, 2-dione (2.69 g, 19.50 mmol) (supplier: Suzhou spark Biotechnology Co., Ltd. CAS# 174953-30-1) at room temperature under air atmosphere. The resulting mixture was stirred at room temperature for 2 h. Then H2O (50 mL) and H2SO4 (10 mL) were added slowly to above mixture at 0 °C. The resulting mixture was stirred at 60 °C overnight. The reaction mixture was basified with NaOH (sat.) to pH -8 and then extracted with dichloromethane. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under vacuum to afford a 1:1 mixture of (S)-l-(((3S,4S)-4-amino-7-(trifluoromethyl)chroman-3-yl)oxy)propan-2-ol and (S)-l-(((3R,4R)-4-amino-7-(trifluoromethyl)chroman-3-yl)oxy)propan-2-ol (4.1 g, 91%) as a brown oil. MS ESI calculated for C13H16F3NO3 [M+H]⁺, 292.11 ; found, 292.10.

Step-3:

[1203] To a 1:1 mixture of a mixture of (S)-l-(((3S,4S)-4-amino-7- (trifluoromethyl)chroman-3-yl)oxy)propan-2-ol and (S)- 1 -(((3R,4R)-4-amino-7- (trifluoromethyl)chroman-3-yl)oxy)propan-2-ol (4.1 g, 13.73 mmol) in MeOH (40 mL) were added DMAP (0.17 g, 1.37 mmol), TEA (2.08 g, 20.59 mmol) and Boc₂O (3.30 g, 15.10 mmol) at 0 °C. The mixture was stirred at 25 °C for 1 h. The resulting mixture was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with PE / EtOAc (0-60%) to afford a 1 : 1 mixture of tert-butyl ((3S,4S)-3-((S)-2-hydroxypropoxy)-7-(trifluoromethyl)chroman-4-yl)carbamate and tertbutyl ((3R,4R)-3-((S)-2-hydroxypropoxy)-7-(trifluoromethyl)chroman-4-yl)carbamate (3.5 g, 65%) as a yellow solid. MS ESI calculated for C18H24F3NO5 [M+l]⁺, 392.16; found, 392.10.

[1204] To a 1:1 mixture of tert-butyl ((3S,4S)-3-((S)-2-hydroxypropoxy)-7- (trifhioromethyl)chroman-4-yl)carbamate and tert-butyl ((3R,4R)-3-((S)-2-hydroxypropoxy)- 7-(trifhioromethyl)chroman-4-yl)carbamate (3.5 g, 8.94 mmol) in DCM (35 mL) were added TEA (4.52 g, 44.71 mmol) and methanesulfonyl methanesulfonate (4.67 g, 26.82 mmol) at 0 °C. The mxiture was stirred at 25 °C for 1 h. The resulting mixture was quenched with water and extracted with DCM. The combined organic layers were washed with brine, dried over anhydrous Na₂SO4. After filtration, the filtrate was concentrated under reduced pressure to afford a 1:1 mixture of (S)-l-(((3S,4S)-4-((tert-butoxycarbonyl)amino)-7- (trifhioromethyl)chroman-3-yl)oxy)propan-2-yl methanesulfonate and (S)-l-(((3R,4R)-4- ((tert-butoxycarbonyl)amino)-7-(trifluoromethyl)chroman-3-yl)oxy)propan-2-yl methanesulfonate (4.0 g, crude) as a brown oil. MS ESI calculated for CigH^FsNOS [M+l]⁺, 470.14; found, 470.05. Step-5:

[1205] To a 1:1 mixture of a mixture of (S)-l-(((3S,4S)-4-((tert-butoxycarbonyl)amino)-7- (trifluoromethyl)chroman-3-yl)oxy)propan-2-yl methanesulfonate and (S)-l-(((3R,4R)-4- ((tert-butoxycarbonyl)amino)-7-(trifluoromethyl)chroman-3-yl)oxy)propan-2-yl methanesulfonate (4.4 g, 9.37 mmol) in DCM (44 mL) was added TFA (15 mL, 201.94 mmol) at 0 °C. The mixture was stirred for 30 min at room temperature. The resulting mixture was concentrated under reduced pressure. The residue was dissolved in MeCN (88 mL), this was followed by the addition of 1,2,2,6,6-pentamethylpiperidine (4.3 g, 28.14 mmol). The mixture was stirred at 80 °C for 2 h. The mixture was quenched with water and extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous NazSCL. After filtration, the filtrate was concentrated under reduced pressure. The resultant oil was purified by prep-HPLC with the following conditions: [Column: XBridge Prep OBD C18 Column, 30*150 mm, 5pm; Mobile Phase A: Water(10mmol/L NH4HCO3), Mobile Phase B: ACN; Flow rate: 60 mL/min; Gradient: 39% B to 54% B in 10 min; Wave Length: 254/220 nm] to afford (2R,4aR,10bR)-2-methyl-8-(trifluoromethyl)-l,2,3,4a,5,10b- hexahydrochromeno[3,4-b][l,4]oxazine (400 mg, 15 %) as a white solid with shorter retention time. MS ESI calculated for C13H14F3NO2 [M+H]+, 274.10; found, 274.00. 'H NMR (400 MHz, DMSO) 5 7.82 (d, J = 8.2 Hz, 1H), 7.25 (d, J = 1.8 Hz, 1H), 7.02 (d, J = 1.8 Hz, 1H), 4.24 (d, J = 2.0 Hz, 2H), 4.07 (d, J= 3.2 Hz, 1H), 3.80 (dt, J= 3.6, 1.8 Hz, 1H), 3.60 (dd, J= 10.6, 3.2 Hz, 1H), 3.10 (t, J = 10.6 Hz, 1H), 2.48 - 2.39 (m, 1H), 0.84 (d, J = 6.4 Hz, 3H). Absolute stereochemistry was determined by NOESY. [1206] The purification also afford (2R,4aS,10bS)-2-methyl-8-(trifluoromethyl)- l,2,3,4a,5,10b-hexahydrochromeno[3,4-b][l,4]oxazine (A48) (400 mg, 15%) as a white solid with longer retention time. MS ESI calculated for C13H14F3NO2 [M+H]+, 274.10; found, 274.05. ^JH NMR (400 MHz, DMSO) 5 7.55 (d, J= 8.0 Hz, 1H), 7.23 (dd, J= 8.2, 1.8 Hz, 1H), 7.09 (d, J= 1.8 Hz, 1H), 4.80 - 4.50 (m, 1H), 4.11 - 3.97 (m, 2H), 3.95 (d, J= 3.8 Hz, 1H), 3.51 (dd, J = 10.8, 3.2 Hz, 1H), 3.19 (dd, 7= 10.8, 9.2 Hz, 1H), 3.01 - 2.91 (m, 1H), 0.86 (d, J = 6.4 Hz, 3H). Absolute stereochemistry was determined by NOESY.

Intermediate A49: 1:1 mixture of (4S,4aS,10bR)-4-methyl-8-(trifluoromethyl)-

1 ,3, 4, 4a, 5, 10b-hexahydro-2H-chromeno[4,3-b]pyridine and (4R,4aR, 10bS)-4-methyl-8-

(trifluoromethyl)-l,3,4,4a,5,10b-hexahydro-2H-chromeno[4,3-b]pyridine

[1207] To a degassed solution of ethyl 2-chloro-4-methylnicotinate (5.0 g, 25.05 mmol) in dioxane (50 mL) and H2O (5 mL) were added (2-methoxy-4-(trifluoromethyl)phenyl)boronic acid (8.26 g, 37.57 mmol), K2CO3 (10.38 g, 75.11 mmol) and Pd(dppf)C12-CH₂C12 (2.04 g, 2.50 mmol). The resulting solution was stirred at 100 °C for 16 h under nitrogen atmosphere. The reaction mixture was quenched by the addition of water and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under vacuum. The resulting residue was purified by Combi Flash (Biotage Isolera Prime) using a 120 g silica gel column eluted with 0-50% ethyl acetate in petroleum ether to afford ethyl 2-(2-methoxy-4-(trifluoromethyl)phenyl)-4-methylnicotinate (8.60 g, 92%) as a yellow oil. MS ESI calculated for C17H16F3NO3 [M+H]⁺, 340.11; found, 340.13.

Step-2:

[1208] To a stirred solution of ethyl 2-(2-methoxy-4-(trifluoromethyl)phenyl)-4- methylnicotinate (8.60 g, 25.35 mmol) in DCM (80 mL) was added BB (1 M in DCM) (88 mL, 88.00 mmol) at 0 °C. The resulting solution was stirred at room temperature for 16 h. The reaction mixture was quenched by the addition of ice water and extracted with dichloromethane. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under vacuum. The resulting residue was purified by Combi Flash (Biotage Isolera Prime) using a 120 g silica gel column eluted with 0-50% ethyl acetate in petroleum ether to afford 4-methyl-8-(trifhioromethyl)-5H- chromeno[4,3-b]pyridin-5-one (8.60 g, 97%) as a white solid. MS ESI calculated for Ci4H₈F₃NO₂ [M+H]⁺, 280.05; found, 280.10.

Step-3:

[1209] To a stirred solution of 4-methyl-8-(trifhioromethyl)-5H-chromeno[4,3-b]pyridin-5- one (8.70 g, 31.16 mmol) in Diethyl ether (100 mL) were sequentially added NH3.BH3 (2.41 g, 78.21 mmol) and T1CI4 (8.6 mL, 78.21 mmol) at 0 °C. The resulting solution was stirred at room temperature for 16 h. The reaction mixture was quenched by the addition of ice water and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under vacuum. The resulting residue was purified by Combi Flash (Biotage Isolera Prime) using a 120 g silica gel column eluted with 0-60% ethyl acetate in petroleum ether to afford 4-methyl-8-(trifluoromethyl)- 5H-chromeno[4,3-b]pyridine (2.10 g, 23%) as a white solid. MS ESI calculated for C14H10F3NO [M+H]⁺, 266.07; found, 266.11.

Step-4:

A49

[1210] To a solution of 4-methyl-8-(trifhioromethyl)-5H-chromeno[4,3-b]pyridine (2.10 g, 7.92 mmol) in AcOH (20 mL) was added Pt/C (5%) (220 mg) at room temperature. The mixture was placed under hydrogen atmosphere with a balloon. The reaction mixture degassed via vacuum evacuation, then backfilled with hydrogen, and this process was repeated three times. The reaction mixture was stirred at room temperature for 48 h under hydrogen atmosphere (1 atm.). The suspension was filtered. The filtrate was collected and concentrated under vacuum. The residue was purified by prep-HPLC with the following conditions: [Column: XBridge Prep OBD C18 Column, 30*150 mm, 5 pm; Mobile Phase A: Water(10mmol/L NH4HCO3), Mobile Phase B: ACN; Flow rate: 60 mL/min; Gradient: 62% B to 77% B in 10 min; Wave Length: 254/220 nm; RTl(min): 6.9] to afford a 1:1 mixture of (4S,4aS,10bR)-4-methyl-8-(trifhioromethyl)-l,3,4,4a,5,10b-hexahydro-2H-chromeno[4,3- b]pyridine and (4R,4aR, 10bS)-4-methyl-8-(trifluoromethyl)- 1 ,3, 4, 4a, 5, 10b-hexahydro-2H- chromeno[4,3-b]pyridine (A49) (400 mg, 18%) as a white solid. MS ESI calculated for C14H16F3NO [M+H]⁺,272.12; found, 272.15. 'H NMR (400 MHz, DMSO-dfi) 8 7.41 (d, J = 7.6 Hz, 1H), 7.15 (dd, 7 = 8.0, 1.2 Hz, 1H), 7.O5 (s, 1H), 4.52 - 4.34 (m, 1H), 4.20 - 4.11 (m, 1H), 3.63 - 3.58 (m, 1H), 3.03 - 2.91 (m, 1H), 2.76 - 2.61 (m, 1H), 2.02 - 1.83 (m, 2H), 1.42 - 1.28 (m, 1H), 1.24 - 1.07 (m, 1H), 0.99 (d, J = 6.8 Hz, 3H). The relative configuration was determined by NOESY.

Intermediate A49 isomer 1: rel-(4R,4aR,10bS)-4-methyl-8-(trifluoromethyl)- l,3,4,4a,5,10b-hexahydro-2H-chromeno[4,3-b]pyridine isomer 1 isomer

Intermediate A49 isomer 2: rel-(4R,4aR,10bS)-4-methyl-8-(trifluoromethyl)- l,3,4,4a,5,10b-hexahydro-2H-chromeno[4,3-b]pyridine isomer 2

Isomer 2

[1211] 1:1 mixture of (4S,4aS,10bR)-4-methyl-8-(trifluoromethyl)-l,3,4,4a,5,10b- hexahydro-2H-chromeno[4,3-b]pyridine and (4R,4aR,10bS)-4-rnethyl-8-(trifluoromethyl)- l,3,4,4a,5,10b-hexahydro-2H-chromeno[4,3-b]pyridine (A49) (350 mg) was purified by Prep-Chiral HPLC with following condition [Column: CHIRALPAK IF, 2*25 cm, 5 pm; Mobile Phase A: Hex (0.5% 2M NH3-MeOH), Mobile Phase B: MEOH: DCM=1: 1-HPLC; Flow rate: 20 mL/min; Gradient (B%): 15% B to 15% B in 9 min; Wave Length: 220/254 nm; RTl(min): 5.82; RT2(min): 6.85; Sample Solvent: EtOH: DCM=1 : 1 — HPLC] to afford rel-(4R,4aR,10bS)-4-methyl-8-(trifhioromethyl)-l,3,4,4a,5,10b-hexahydro-2H- chromeno[4,3-b]pyridine isomer 1 (A49 isomer 1) (120 mg) as a white solid with retention time at 5.82 minute. MS ESI calculated for C14H16F3NO [M+H]⁺,272.12; found, 272.15. 'H NMR (400 MHz, DMSO-d<s) 8 7.41 (d, J = 7.6 Hz, 1H), 7.15 (dd, J = 8.0, 1.2 Hz, 1H), 7.05 (s, 1H), 4.52 - 4.34 (m, 1H), 4.20 - 4.11 (m, 1H), 3.63 - 3.58 (m, 1H), 3.03 - 2.91 (m, 1H), 2.76 - 2.61 (m, 1H), 2.02 - 1.83 (m, 2H), 1.42 - 1.28 (m, 1H), 1.24 - 1.07 (m, 1H), 0.99 (d, J = 6.8 Hz, 3H). Absolute stereochemistry was not determined.

[1212] The chiral resolution also afford rel-(4R,4aR,10bS)-4-methyl-8-(trifluoromethyl)- l,3,4,4a,5,10b-hexahydro-2H-chromeno[4,3-b]pyridine isomer 2 (A49 isomer 2) (120 mg) as a white solid with retention time at 6.85 minute. MS ESI calculated for C14H16F3NO [M+H]⁺, 272.12; found, 272.15. 'H NMR (400 MHz, DMSO-tfc) 8 7.41 (d, J = 7.6 Hz, 1H), 7.15 (dd, J= 8.0, 1.2 Hz, 1H), 7.05 (s, 1H), 4.52 - 4.34 (m, 1H), 4.20 - 4.11 (m, 1H), 3.63 - 3.58 (m, 1H), 3.03 - 2.91 (m, 1H), 2.76 - 2.61 (m, 1H), 2.02 - 1.83 (m, 2H), 1.42 - 1.28 (m, 1H), 1.24 - 1.07 (m, 1H), 0.99 (d, J = 6.8 Hz, 3H). Absolute stereochemistry was not determined.

Intermediate A50: (3R,4aS,9aR)-3-methyl-2,3,4,4a,9,9a-hexahydroindeno[2,l- b][ 1,4] oxazine

Step 1:

[1213] A mixture of (lS,2R)-l-amino-2,3-dihydro-lH-inden-2-ol (10.0 g, 67.02 mmol) (supplier: Accela ChemBio Co., Ltd. CAS# 126456-43-7), TEA (13.57 g, 134.10 mmol) and BociO (21.94 g, 100.54 mmol) in MeOH (100 mL) was stirred at room temperature for 16 h. The resulting mixture was concentrated under reduced pressure. The residue was purified by flash column chromatography with 0-33% EtOAc in PE to afford tert-butyl ((lS,2R)-2- hydroxy-2,3-dihydro-lH-inden-l-yl)carbamate (16.7 g, 99%) as a white solid. MS ESI calculated for C14H19NO3 [M+H]⁺, 250.14; found, 250.25. 'H NMR (300 MHz, DMSO-d₆) 8 (ppm) 7.24 - 7.18 (m, 4H), 6.39 (d, J = 8.7 Hz, 1H), 5.00 (d, J = 4.2 Hz, 1H), 4.93 - 4.84 (m, 1H), 4.44 - 4.36 (m, 1H), 3.06 - 2.95 (m, 1H), 2.83 - 2.75 (m, 1H), 1 .45 (s, 9H).

Step-2: [1214] To a stirred solution of tert-butyl ((lS,2R)-2-hydroxy-2,3-dihydro-lH-inden-l- yl)carbamate (16.7 g, 68.18 mmol), tetrabutylazanium hydrogen sulfate (4.63 g, 13.63 mmol) and NaOH (19.09 g, 477.31 mmol) in DCM (170 mL) was added (S)-4-methyl- 1,3,2- dioxathiolane 2,2-dioxide (12.25 g, 88.64 mmol) (supplier: Suzhou spark Biotechnology Co., Ltd. CAS# 174953-30-1) at room temperature under nitrogen atmosphere. The resulting mixture was stirred at room temperature for 1 h. The resulting mixture was concentrated under reduced pressure. The residue was dissolved in H2O (170 mL), this was followed by the addition of H2SO4 (66.87 g, 681.88 mmol) slowly at 0 °C. The resulting mixture was stirred at 60 °C for 16 h. The reaction mixture was basified with NaOH (aq.) to pH ~8 and extracted with dichloromethane. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered and concentrated under vacuum to afford (S)-l- (((lS,2R)-l-amino-2,3-dihydro-lH-inden-2-yl)oxy)propan-2-ol (17.8 g, 68% yield, 54% purity) as a brown oil. MS ESI calculated for C12H17NO2 [M+H]⁺, 208.13; found, 208.15.

Step 3:

[1215] A mixture of (S)-l-(((lS,2R)-l-amino-2,3-dihydro-lH-inden-2-yl)oxy)propan-2-ol (5.0 g, 24.12 mmol), BOC2O (7.9 g, 36.18 mmol) and TEA (4.88 g, 48.24 mmol) in MeOH (50 mL) was stirred at room temperature for 16 h. The resulting mixture was concentrated under reduced pressure. The residue was purified by flash column chromatography with 0- 50% EtOAc in PE to afford tert-butyl ((lS,2R)-2-((S)-2-hydroxypropoxy)-2,3-dihydro-lH- inden-l-yl)carbamate (2.98 g, 40%) as a white solid. MS ESI calculated for C17H25NO4 [M+H]⁺, 308.18; found, 308.10.

Step 4:

[1216] To a solution of tert-butyl ((lS,2R)-2-((S)-2-hydroxypropoxy)-2,3-dihydro-lH- inden-l-yl)carbamate (2.98 g, 9.69 mmol) and TEA (4.91 g, 48.47 mmol) in DCM (30 mL) was added methanesulfonyl methanesulfonate (6.75 g, 38.78 mmol) at 0 °C. The resulting mixture was stirred at room temperature for 1 h. The reaction mixture was quenched with saturated NaHCCh (aq.) and extracted with DCM. The combined organic layers were washed with brine, dried over anhydrous Na2SC>4. After filtration, the filtrate was concentrated under reduced pressure. The residue was dissolved in DCM (30 mL) and trifluoroacetic acid (10 mL) at room temperature. The resulting mixture was stirred at room temperature for 1 h. The resulting mixture was concentrated under vacuum. Then the residue was dissolved acetonitrile (60 mL), this was followed by the addition of 1,2,2,6,6-pentamethylpiperidine (4.52 g, 29.10 mmol) at room temperature. The resulting mixture was stirred at 80 °C for 16 h. The reaction mixture was concentrated under reduced pressure. The residue was purified by reverse phase flash column chromatography with 10% ~ 60% MeCN in water (10 mmol/L NH4HCO3) to afford (3R,4aS,9aR)-3-methyl-2,3,4,4a,9,9a-hexahydroindeno[2,l- b][ 1,4] oxazine (A50) (473 mg, 23%) as a brown oil. MS ESI calculated for C12H15NO [M4-H]⁺, 190.12; found, 190.05. 'H NMR (400 MHz, DMSO- ₆) 8 (ppm) 7.34 - 7.30 (m, 1H), 7.29 - 7.11 (m, 3H), 4.22 - 4.15 (m, 1H), 3.98 (d, J= 5.2 Hz, 1H), 3.53 - 3.49 (m, 1H), 3.30 - 3.16 (m, 2H), 2.84 - 2.70 (m, 2H), 0.84 (d, J= 6.4 Hz, 3H).

Intermediate A51, isomer 1: rel-(3R,4aS,9bR)-7-(difluoromethoxy)-3-methoxy- 2,3,4,4a,5,9b-hexahydro-lH-indeno[l,2-b]pyridine isomer 1

A51 isomer 1 _an(^

Intermediate A51, isomer 2: rel- rel-(3S,4aR,9bS)-7-(difluoromethoxy)-3-methoxy-

2,3,4,4a,5,9b-hexahydro-lH-indeno[l,2-b]pyridine isomer 2

A51 isomer 2 _an(j

Intermediate A51, isomer 3: rel-(3S,4aS,9bR)-7-(difluoromethoxy)-3-methoxy- 2,3,4,4a,5,9b-hexahydro-lH-indeno[l,2-b]pyridine isomer 3

A51 isomer 3 _ar)(j

Intermediate A51, isomer 4: rel- (3R,4aR,9bS)-7-(difluoromethoxy)-3-methoxy- 2,3,4,4a,5,9b-hexahydro-lH-indeno[l,2-b]pyridine isomer 4

Step-1:

[1217] To a stirred solution of methyl 5-bromo-2-chloronicotinate (200.0 g, 798.46 mmol) and 4,4,4',4',5,5,5',5'-octamethyl-2,2'-bi(1 ,3,2-dioxaborolane) (202.7 g, 798.46 mmol) in 1,4- dioxane (2000 mL) were added AcOK (155.9 g, 1588.94 mmol) and Pd(dppf)C12-CH2Ch (65.0 g, 79.84 mmol) in portions at room temperature. The resulting mixture was stirred at 80 °C for 16 h under nitrogen atmosphere. The resulting mixture was filtered, the filter cake was washed with ethyl acetate. The filtrate was concentrated under reduced pressure. The residue was purified by flash column chromatography with 0-20% ethyl acetate in petroleum ether to afford methyl 2-chloro-5-(4,4,5,5-tetramethyl-l,3,2-dioxaborolan-2-yl)nicotinate (95.0 g, 28%) as a light green solid. MS ESI calculated for C13H17BCINO4 [M+H]⁺, 298.10; found, 298.05.

Step-2:

[1218] To a stirred solution of methyl 2-chloro-5-(4,4,5,5-tetramethyl-l,3,2-dioxaborolan- 2-yl)nicotinate (95.0 g, 319.28 mmol) in EtOH (1000 mL) and H2O (1000 mL) was added sodium perborate (5.6 g, 69.23 mmol) in portions at 0 °C. The resulting mixture was stirred at room temperature for 4 h. The mixture was concentrated under reduced pressure. The residue was was quenched with water and acidified with HC1 (aq., 2 N) to pH 5~6. The mixture was extracted with ethyl acetate. The organic layers were dried over anhydrous sodium sulfate, filtered and concentrated to afford methyl 2-chloro-5-hydroxynicotinate (95.0 g, crude) as a brown solid. MS ESI calculated for C7H6CINO3 [M+H]⁺, 188.00; found, 188.01.

Step-3:

[1219] To a stirred solution of methyl 2-chloro-5-hydroxynicotinate (95.0 g, 506.45 mmol) and K2CO3 (210.0 g, 1519.35 mmol) in DMF (2000 mL) was added Mel (86.26 g, 607.74 mmol) at 0 °C. The mixture was stirred at room temperature for 4 h. The resulting mixture was filtered, the filter cake was washed with ethyl acetate. The filtrate was quenched with water. The aqueous layer was extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous Na2SC>4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by flash column chromatography with 0-50% ethyl acetate in petroleum ether to afford methyl 2-chloro-5- methoxynicotinate (45.0 g, 44%) as a yellow solid. MS ESI calculated for CgHgClNCh [M+H]⁺, 202.02; found, 202.04.

Step-4:

[1220] To a degassed solution of methyl 2-chloro-5-methoxyrricotinate (45.0 g, 223.20 mmol) and (4-(difluoromethoxy)phenyl)boronic acid (43.2 g, 229.89 mmol) in DME (500 mL) and H2O (100 mL) were added Pd(PPha)4 (25.7 g, 22.32 mmol) and NazCCh (71.9 g, 678.53 mmol). The mixture was stirred at 90 °C for 16 h under nitrogen atmosphere. The reaction mixture was concentrated under reduced pressure. The residue was quenched with water and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous Na2SC>4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by flash column chromatography with 0-30% ethyl acetate in petroleum ether to afford methyl 2-(4-(difluoromethoxy)phenyl)-5- methoxynicotinate (45.0 g, 57%) as a white solid. MS ESI calculated for C15H13F2NO4 [M+H]⁺, 310.08; found, 310.02.

Step-5:

[1221] To a stirred solution of methyl 2-(4-(difluoromethoxy)phenyl)-5-methoxynicotinate (45.0 g, 145.50 mmol) and CaCl₂ (24.2 g, 218.25 mmol) in THF (300 mL) and EtOH (300 mL) was added NaBFU (16.5 g, 436.51 mmol) in portions at 0 °C. The mixture was stirred at room temperature for 16 h. The reaction was quenched with ice water and then extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under vacuum. The residue was purified by flash column chromatography with 0-40% ethyl acetate in petroleum ether to afford (2-(4- (difluoromethoxy)phenyl)-5-methoxypyridin-3-yl)methanol (38.0 g, 93%) as a white solid. MS ESI calculated for C14H13F2NO3 [M+H]⁺, 282.09; found, 282.04.

Step-6:

[1222] To a stirred solution of (2-(4-(difluoromethoxy)phenyl)-5-methoxypyridin-3- yl)methanol (34.0 g, 120.88 mmol) in DCM (400 mL) was added Thionyl chloride (71.9 g, 604.42 mmol) dropwise at 0 °C. The mixture was stirred at 0 °C for 4 h. The reaction mixture was concentrated under reduced pressure. The residue was treated with NaHCCh (sat.) and extracted with DCM. The combined organic layers were washed with brine, dried over anhydrous NazSC . After filtration, the filtrate was concentrated under reduced pressure afford 3-(chloromethyl)-2-(4-(difhioromethoxy)phenyl)-5-methoxypyridine (30.0 g, crude) as a yellow oil. MS ESI calculated for C14H12CIF2NO2 [M+H]⁺, 300.05; found, 300.02.

Step-7:

[1223] To a degassed solution of 3-(chloromethyl)-2-(4-(difluoromethoxy)phenyl)-5- methoxypyridine (30.0 g, 100.10 mmol) in DME (300 mL) were added Pd(OAc)2 (2.2 g, 10.01 mmol), tris(3-methylphenyl)phosphane (6.1 g, 20.02 mmol) and Na2COg (31.8 g, 300.30 mmol). The mixture was stirred at 110 °C for 16 h under nitrogen atmosphere. The resulting mixture was concentrated under reduced pressure. The residue was quenched with water and was extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under vacuum. The residue was purified by flash column chromatography with 0-40% ethyl acetate in petroleum ether to afford 7-(difluoromethoxy)-3-methoxy-5H-indeno[l,2-b]pyridine (11.2 g, 42%) as a white solid. MS ESI calculated for C14H11F2NO2 [M+H]⁺, 264.08; found, 264.04.

Step-8:

[1224] To a solution of 7-(difhioromethoxy)-3-methoxy-5H-indeno[l,2-b]pyridine (11.0 g, 41.78 mmol) in i-PrOH (100 mL) was added Pd(OH)2/C (20% active in carbon, wetted with ca. 50% water) (11.7 g, 83.57 mmol). The mixture was stirred at 50 °C for 72 h under hydrogen atmosphere (20 atm). The resulting mixture was filtered, the filter cake was washed with MeOH. The filtrate was concentrated under reduced pressure. The residue was purified by flash column chromatography with 0-20% dichloromethane in methanol to afford the mixture (7.5 g, 67%) as a colorless oil.

[1225] The mixture (7.5 g) was separated by Prep-Achiral-SFC with the following conditions [Column: GreenSep Basic 3*15 cm, 5 pm; Mobile Phase A: CO2, Mobile Phase B: IPA (1% 2M NH3-MEOH); Flow rate: 75 mL/min; Gradient (B%): isocratic 32% B; Column Temperature(20 °C): 35; Back Pressure(bar): 100; Wave Length: 254 nm; RTl(min): 3.88; RT2(min): 4.33; Sample Solvent: MeOH— HPLC] to afford fraction A that is a 1:1 mixture of rel-(3S,4aS,9bR)-7-(difluoromethoxy)-3-methoxy-2,3,4,4a,5,9b-hexahydro-lH-indeno[l,2- b]pyridine and rel- (3R,4aR,9bS)-7-(difluoromethoxy)-3-methoxy-2,3,4,4a,5,9b-hexahydro- lH-indeno[l,2-b]pyridine (0.7 g, 8%) as a brown oil. MS ESI calculated for C14H17F2NO2 [M+H]⁺, 270.12; found, 270.08. 'H NMR (400 MHz, DMSO-d₆) 8 7.38 - 6.94 (m, 4H), 4.11 (d, J= 5.6 Hz, 1H), 3.27 (s, 3H), 3.22 - 3.17 (m, 1H), 2.88 - 2.77 (m, 1H), 2.69 - 2.61 (m, 2H), 2.57 - 2.43 (m, 3H), 1.78 - 1.66 (m, 1H), 1.57 - 1.39 (m, 1H). [1226] The Achiral SFC process also afford fraction B that is a 1 : 1 mixture of rel- (3R,4aR,9bS)-7-(difluoromethoxy)-3-methoxy-2,3,4,4a,5,9b-hexahydro-lH-indeno[l,2- b]pyridine and rel-(3S,4aR,9bS)-7-(difluoromethoxy)-3-methoxy-2,3,4,4a,5,9b-hexahydro- lH-indeno[l,2-b]pyridine (4.0 g, 53%) as a brown oil. MS ESI calculated for C14H17F2NO2 [M+H]⁺, 270.12; found, 270.08. ¹H NMR (400 MHz, DMSO-d₆) 8 7.37 - 6.98 (m, 4H), 4.18 (d, J= 6.0 Hz, 1H), 3.19 (s, 3H), 3.14 - 3.04 (m, 1H), 2.93 - 2.84 (m, 2H), 2.48 - 2.39 (m, 2H), 2.11 - 1.90 (m, 2H), 1.38 - 1.17 (m, 1H), 0.88 - 0.74 (m, 1H).

Step-9:

[1227] The fraction B (4.0 g) was separated by Prep-Chiral-HPLC with the following conditions [Column: CHIRAL ART Cellulose-SB, 2*25 cm, 5 pm; Mobile Phase A: Hex(0.5% 2M NH₃-MeOH), Mobile Phase B: EtOH: DCM=1: L-HPLC; Flow rate: 20 mL/min; Gradient (B%): 5% B to 5% B in 12 min; Wave Length: 220/254 nm; RTl(min): 8.2; RT2(min): 9.93; Sample Solvent: EtOH: DCM=1: 1-HPLC] to afford rel-(3R,4aR,9bS)- 7-(difluoromethoxy)-3-methoxy-2,3,4,4a,5,9b-hexahydro-lH-indeno[l ,2-b]pyridine isomer 1 (A51 isomer 1) (1.6 g, 40%) as a brown oil with shorter retention time. MS ESI calculated for (C14H17F2NO2) [M+l]⁺, 270.12; found, 270.08. 'H NMR (400 MHz, DMSO-d₆) 8 7.37 - 6.98 (m, 4H), 4.18 (d, J = 6.0 Hz, 1H), 3.19 (s, 3H), 3.14 - 3.04 (m, 1H), 2.93 - 2.84 (m, 2H), 2.48 - 2.39 (m, 2H), 2.11 - 1.90 (m, 2H), 1.38 - 1.17 (m, 1H), 0.88 - 0.74 (m, 1H). NOESY shows all the groups of pyridine are cis, but the absolute configuration is undetermined. [1228] The chiral resolution also afford rel-(3S,4aR,9bS)-7-(difluoromethoxy)-3-methoxy- 2,3,4,4a,5,9b-hexahydro-lH-indeno[l,2-b]pyridine (A51 isomer 2) (2.0 g, 50%) as a brown oil with longer retention time. MS ESI calculated for (C14H17F2NO2) [M+l]⁺, 270.12; found, 270.08. 'H NMR (400 MHz, DMSO- ₆) 87.37 - 6.98 (m, 4H), 4.18 (d, J= 6.0 Hz, 1H), 3.19 (s, 3H), 3.14 - 3.04 (m, 1H), 2.93 - 2.84 (m, 2H), 2.48 - 2.39 (m, 2H), 2.11 - 1.90 (m, 2H), 1.38 - 1.17 (m, 1H), 0.88 - 0.74 (m, 1H). NOESY shows all the groups of pyridine are cis, but the absolute configuration is undetermined.

Step- 10:

A51 isomer 4

[1229] The fraction A (660 mg) was separated by Prep-Chiral-HPLC with the following conditions [Column: CHIRALPAK IG, 5*25 cm, 10 pm; Mobile Phase A: Hex— HPLC-, Mobile Phase B: MEOH: DCM=1 : 1(1% 2M NH3-MEOH); Flow rate: 100 mL/min; Gradient (B%): isocratic ; Wave Length: 220 rnn; RTl(min): 6.54; RT2(min): 8.45; Sample Solvent: Hex-HPLC] to afford rel-(3S,4aS,9bR)-7-(difluoromethoxy)-3-methoxy-2,3,4,4a,5,9b- hexahydro-lH-indeno[l,2-b]pyridine (A51 isomer 3) (200 mg, 31%) as a colorless oil with shorter retention time. MS ESI calculated for C14H17F2NO2 [M+H]⁺, 270.12; found, 270.08. ¹H NMR (400 MHz, DMSO-d₆) 87.38 - 6.94 (m, 4H), 4.11 (d, J = 5.6 Hz, 1H), 3.27 (s, 3H), 3.22 - 3.17 (m, 1H), 2.88 - 2.77 (m, 1H), 2.69 - 2.61 (m, 2H), 2.57 - 2.43 (m, 3H), 1.78 - 1.66 (m, 1H), 1.57 - 1.39 (m, 1H). NOESY shows the -OMe group is at the trans position, but the absolute configuration is undetermined. [1230] The chiral resolution also afford rel-(3R,4aR,9bS)-7-(difluoromethoxy)-3-methoxy- 2,3,4,4a,5,9b-hexahydro-lH-indeno[l,2-b]pyridine (A51 isomer 4) (210 mg, 32%) as a colorless oil with longer retention time. MS ESI calculated for C14H17F2NO2 [M+H]⁺, 270.12; found, 270.08. 'H NMR (400 MHz, DMSO- ₆) 8 7.38 - 6.94 (m, 4H), 4.11 (d, J= 5.6 Hz, 1H), 3.27 (s, 3H), 3.22 - 3.17 (m, 1H), 2.88 - 2.77 (m, 1H), 2.69 - 2.61 (m, 2H), 2.57 - 2.43 (m, 3H), 1.78 - 1.66 (m, 1H), 1.57 - 1.39 (m, 1H). NOESY shows the -OMe group is at the trans position, but the absolute configuration is undetermined.

Intermediate A52: 1 : 1 mixture of rel-(3R,4aS,9bR)-7-(difluoromethoxy)-3-fluoro- 2,3,4,4a,5,9b-hexahydro-lH-indeno[l,2-b]pyridine isomer 1 and rel-(3R,4aS,9bR)-7- (difluoromethoxy)-3-fluoro-2,3,4,4a,5,9b-hexahydro-lH-indeno[l ,2-b]pyridine isomer 2

A52

Step-1:

[1231] To a stirred solution of 2-chloro-5-fluoronicotinic acid (20.00 g, 114 mmol) in THF (200 mL) was added BH3-THF (1.0M in THF, 341 mL) dropwise at 0 °C under nitrogen atmosphere. The resulting mixture was stirred at room temperature overnight. Then the reaction was quenched by the addition of ice water at room temperature. The resulting mixture was extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous Na2SC>4. After filtration, the filtrate was concentrated under reduced pressure to afford (2-chloro-5-fluoropyridin-3-yl)methanol (18.70 g, crude) as a yellow oil. MS ESI calculated for C₆H₅C1FNO [M+H]⁺, 162.00; found, 162.10.

Step-2:

[1232] To a stirred solution of (2-chloro-5-fluoropyridin-3-yl)methanol (9.40 g, 58 mmol) and (4-(difhioromethoxy)phenyl)boronic acid (12.03 g, 64.00 mmol) in DME (120 mL) and H2O (40 mL) was added Na₂CO₃ (24.67 g, 232.73 mmol) and Pd(PPh₃)₄ (13.95 g, 12.07 mmol) at room temperature under nitrogen atmosphere. The resulting mixture was stirred at 90 °C overnight. The mixture was allowed to cool down to room temperature. The reaction mixture was quenched with water and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous Na2SO₄. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0 ~ 30% EtOAc in PE to afford (2-(4- (difhioromethoxy)phenyl)-5-fluoropyridin-3-yl)methanol (7.00 g, 44%) as a yellow solid. MS ESI calculated for CI₃HIOF₃N02 [M+H]⁺, 270.07; found, 270.05.

Step-3:

[1233] To a stirred solution of (2-(4-(difluoromethoxy)phenyl)-5-fluoropyridin-3- yl)methanol (26.00 g, 96.57 mmol) in DCM (300 mL) were added SOCI2 (46.8 mL) dropwise at 0 °C under nitrogen atmosphere. The resulting mixture was stirred at room temperature for 4 h. The reaction was quenched by the addition of water at 0 °C and extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SO₄. After filtration, the filtrate was concentrated under reduced pressure to afford 3-(chloromethyl)-2- (4-(difluoromethoxy)phenyl)-5-fluoropyridine (25.10 g, crude) as a yellow oil. MS ESI calculated for C13H9CIF3NO [M+H]⁺, 288.03; found, 288.05.

Step-4:

[1234] To a stirred solution of 3-(chloromethyl)-2-(4-(difluoromethoxy)phenyl)-5- fluoropyridine (25.10 g, 87.25 mmol) and Na?CO3 (36.99 g, 349.01 mmol) in DME (335 mL) were added Pd(OAc)2 (1.96 g, 8.72 mmol) and P(m-Tol)3 (5.31 g, 17.45 mmol) at room temperature under nitrogen atmosphere. The resulting mixture was stirred at 110 °C for overnight. The mixture was allowed to cool down to room temperature. The resulting mixture was quenched with water and extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SC>4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0 ~ 20% EtOAc in PE to afford 7-(difluoromethoxy)-3-fluoro- 5H-indeno[l,2-b]pyridine (16.00 g, 73%) as a yellow solid. MS ESI calculated for C25H27F3N4O3 [M+H]⁺, 489.20; found, 489.20.

Step-5:

[1235] To a solution of 7-(difluoromethoxy)-3-fluoro-5H-indeno[l,2-b]pyridine (7.50 g, 29.86 mmol) in THF (100 mL) and H₂O (100 mL) was added H2SO4 (7.03 g, 71.65 mmol) and Pd(OH)2/C (5%) (2.10 g, 14.93 mmol). The mixture was stirred at 40 °C under hydrogen pressure (50 atm.) overnight. The mixture was filtered through a Celite pad. The filtrate was concentrated under reduced pressure. The resulting mixture was quenched with water and basified with NaOH (aq.) to PH 9. The resulting mixture was extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous Na2SC>4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by reverse phase flash column chromatography with, 5% to 50% MeCN in water to afford a 1:1 mixture of rel-(3R,4aS,9bR)-7-(difhioromethoxy)-3-fluoro-2,3,4,4a,5,9b-hexahydro-lH- indeno[l,2-b]pyridine isomer 1 and rel-(3R,4aS,9bR)-7-(difluoromethoxy)-3-fluoro- 2,3,4,4a,5,9b-hexahydro-lH-indeno[l,2-b]pyridine isomer 2 (A52) (960 mg, 12% yield) as a yellow oil. MS ESI calculated for C13H14F3NO [M+H]⁺, 258.10; found, 258.10. ¹H NMR (400 MHz, DMSO-d₆) 5 7.41 - 6.98 (m, 4H), 4.70 - 4.51 (m, 1H), 4.24 - 4.21 (m, 1H), 3.07 - 2.79 (m, 2H), 2.72 - 2.40 (m, 3H), 2.35 - 1.84 (m, 1H), 1.48 - 1.21 (m, 1H).

Intermediate A52 isomer 1: rel-(3R,4aS,9bR)-7-(difluoromethoxy)-3-fluoro-2,3,4,4a,5,9b- hexahydro-lH-indeno[l,2-b]pyridine isomer 1

A52 Isomer 1 _an(

Intermediate A52 isomer 2: rel-(3R,4aS,9bR)-7-(difluoromethoxy)-3-fluoro-2,3,4,4a,5,9b- hexahydro-lH-indeno[l,2-b]pyridine isomer 2

A52 Isomer 2

[1236] 1:1 mixture of rel-(3R,4aS,9bR)-7-(difluoromethoxy)-3-fluoro-2,3,4,4a,5,9b- hexahydro-lH-indeno[l,2-b]pyridine isomer 1 and rel-(3R,4aS,9bR)-7-(difluoromethoxy)-3- fluoro-2,3,4,4a,5,9b-hexahydro-lH-indeno[l,2-b]pyridine isomer 2 (350 mg) was separated by prep-chiral SFC with the following conditions: [Column: YMC-Actus Triart Diol-HILIC 3*25 cm, 5 pm; Mobile Phase A: CO2, Mobile Phase B: MEOH (20 mM NH3); Flow rate: 75 mL/min; Gradient: isocratic 15% B; Column Temperature(°C): 35; Back Pressure(bar): 100; Wave Length: 254 nm; RTl(min): 4.40; RT2(min): 6.27; Sample Solvent: MEOH] to afford rel-(3R,4aS,9bR)-7-(difluoromethoxy)-3-fluoro-2,3,4,4a,5,9b-hexahydro-lH-indeno[l,2- b]pyridine isomer 1 (A52 isomer 1) (124 mg, 35% yield) as a yellow oil with retention time at 4.40 minute. MS ESI calculated for C13H14F3NO [M+H]⁺, 258.10; found, 258.10. NMR (400 MHz, DMSO) 5 7.40 - 6.95 (m, 4H), 4.62 - 4.35 (m, 1H), 4.16 (t, J = 5.2 Hz, 1H), 2.97 - 2.69 (m, 3H), 2.60 - 2.53 (m, 1H), 2.34 - 2.28 (m, 1H), 2.10 - 1.94 (m, 1H), 1.22 - 1.07 (m, 1H).

[1237] The chiral resolution also afford rel-(3R,4aS,9bR)-7-(difhioromethoxy)-3-fluoro- 2,3,4,4a,5,9b-hexahydro-lH-indeno[l ,2-b]pyridine isomer 2 (A52 isomer 2) (124 mg, 35% yield) as a yellow oil with retention time at 6.27 minute. MS ESI calculated for C13H14F3NO [M+H]⁺, 258.10; found, 258.10. 'H NMR (400 MHz, DMSO) 8 7.40 - 6.95 (m, 4H), 4.62 - 4.35 (m, 1H), 4.16 (t, J = 5.2 Hz, 1H), 2.97 - 2.69 (m, 3H), 2.60 - 2.53 (m, 1H), 2.34 - 2.28 (m, 1H), 2.10 - 1.94 (m, 1H), 1.22 - 1.07 (m, 1H). Intermediate A53: (3R,4aS,9aR)-3,7-dimethyl-2,3,4,4a,9,9a-hexahydroindeno[2,l- b][ 1,4] oxazine

Step-1:

[1238] A mixture of 5-methyl-2,3-dihydro-lH-inden-l-one (20.0 g, 136.81 mmol) and Bn (21.86 g, 136.81 mmol) in Et2O (200 mL) was stirred at room temperature for 0.5 h. The reaction mixture was quenched with sodium thiosulfate (sat.) at room temperature. The resulting mixture was extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous NaiSCL. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by flash column chromatograph 0-25% EtOAc in PE to afford a 1:1 mixture of (R)-2-bromo-5-methyl-2,3-dihydro-lH-inden-l-one and (S)-2- bromo-5-methyl-2,3-dihydro-lH-inden-l-one (27.0 g, 85%) as a yellow solid. MS ESI calculated for CioH₉BrO [M+H]⁺, 224.98; found, 224.95. 'H NMR (300 MHz, DMSO-d₆) 6 (ppm) 7.65 (d, J = 7.8 Hz, 1H), 7.39 (s, 1H), 7.33 (d, J = 7.8 Hz, 1H), 5.02 - 4.97 (m, 1H), 3.89 - 3.79 (m, 1H), 3.32 - 3.24 (m, 1H), 2.43 (s, 3H).

Step-2:

[1239] To a solution of 1: 1 mixture of (R)-2-bromo-5-methyl-2,3-dihydro-lH-inden-l-one and (S)-2-bromo-5-methyl-2,3-dihydro-lH-inden-l-one (27.0 g, 119.96 mmol) in EtOH (270 mL) was added NaBFU (2.27 g, 59.98 mmol) at room temperature. The mixture was stirred at room temperature for 1 h. The reaction mixture was quenched with water at room temperature and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous NazSC . After filtration, the filtrate was concentrated under reduced pressure to afford a 1:1 mixture of (lS,2R)-2-bromo-5-methyl-2,3-dihydro-lH- inden-l-ol and (lR,2S)-2-bromo-5-methyl-2,3-dihydro-lH-inden-l-ol (32.00 g, crude) as a white solid. MS ESI calculated for CioHnBrO [M+l]⁺, 227.00, 229.00; found, 226.95, 228.95.

Step-3:

[1240] A mixture of 1:1 mixture of (lS,2R)-2-bromo-5-methyl-2,3-dihydro-lH-inden-l-ol and (lR,2S)-2-bromo-5-methyl-2,3-dihydro-lH-inden-l-ol (32.0 g, 140.91 mmol), ACN (17.35 g, 422.72 mmol) and H2SO4 (20.73 g, 211.36 mmol) in DCE (320 mL) was stirred at 50 °C for 1 h. Then H2O (213 mL) was added to the mixture at 50 °C. The resulting mixture was stirred at 60 °C for 16 h. The reaction mixture was basified with NaOH to pH 12. The precipitated solids were collected by filtration and washed with water to afford a 1 : 1 mixture of (lS,2R)-l-amino-5-methyl-2,3-dihydro-lH-inden-2-ol and (lR,2S)-l-amino-5-methyl-2,3- dihydro-lH-inden-2-ol (6.9 g, 35% over 2 steps) as a white solid. MS ESI calculated for C10H13NO [M+H]⁺, 164.10; found, 164.10.

Step-4:

[1241] A solution of 1:1 mixture of (lS,2R)-l-amino-5-methyl-2,3-dihydro-lH-inden-2-ol and (lR,2S)-l-amino-5-methyl-2,3-dihydro-lH-inden-2-ol (6.90 g, 42.27 mmol), BOC2O (13.84 g, 63.41 mmol) and TEA (8.56 g, 84.55 mmol) in MeOH (70 mL) was stirred at room temperature for lh. The resulting mixture was concentrated under reduced pressure. The residue was purified by flash column chromatography with 0-30% EtOAc in PE to afford a 1:1 mixture of tert-butyl ((lS,2R)-2-hydroxy-5-methyl-2,3-dihydro-lH-inden-l-yl)carbamate and tert-butyl ((lR,2S)-2-hydroxy-5-methyl-2,3-dihydro-lH-inden-l-yl)carbamate (6.89 g, 59%) as a white solid. MS ESI calculated for C15H21NO3 [M+H]⁺, 264.15; found, 264.10. NMR (400 MHz, DMSO-J₆) 8 (ppm) 7.06 (d, J= 7.6 Hz, 1H), 7.03 - 6.95 (m, 2H), 6.29 (d, J = 8.8 Hz, 1H), 4.94 (d, J = 4.8 Hz, 1H), 4.86 - 4.80 (m, 1H), 4.44 - 4.35 (m, 1H), 2.99 - 2.93 (m, 1H), 2.77 - 2.71 (m, 1H), 2.27 (s, 3H), 1.45 (s, 9H).

Step-5:

[1242] To a mixture of 1 : 1 mixture of tert-butyl ((lS,2R)-2-hydroxy-5-methyl-2,3-dihydro- lH-inden-l-yl)carbamate and tert-butyl ((lR,2S)-2-hydroxy-5-methyl-2,3-dihydro-lH-inden- l-yl)carbamate (6.87 g, 26.09 mmol), (4S)-4-methyl-l, 3, 2-X-6-dioxathiolane-2, 2-dione (4.68 g, 33.91 mmol) (supplier: Suzhou spark Biotechnology Co., Ltd. CAS# 174953-30-1) and NaOH (7.30 g, 182.62 mmol) in DCM (70 mL) was added tetrabutylazanium hydrogen sulfate (1.77 g, 5.22 mmol). The resulting mixture was stirred at room temperature for 1 h. The resulting mixture was concentrated under reduced pressure. Then the residue was dissolved in H2O (70 mL), then H2SO4 (25.58 g, 260.88 mmol) was added. The resulting mixture was stirred at 60 °C for 16 h. The reaction mixture was basified with NaOH to pH 8 The precipitated solids were collected by filtration and washed with H2O to afford a 1:1 mixture of (S)- 1-((( 1 S,2R)- 1 -amino-5-methyl-2,3-dihydro- lH-inden-2-yl)oxy)propan-2-ol and (S)-l-(((lR,2S)-l-amino-5-methyl-2,3-dihydro-lH-inden-2-yl)oxy)propan-2-ol (6.0 g, crude) as a white solid. MS ESI calculated for C13H19NO2 [M+H]⁺, 222.14; found, 222.10. [1243] A solution of 1:1 mixture of (S)-l-(((lS,2R)-l-amino-5-methyl-2,3-dihydro-lH- inden-2-yl)oxy)propan-2-ol and (S)-l -((( 1R,2S)- 1 -amino-5-methyl-2,3-dihydro- lH-inden-2- yl)oxy)propan-2-ol (6.0 g, 27.11 mmol), BoczO (8.88 g, 40.67 mmol), TEA (5.49 g, 54.23 mmol) and DMAP (0.33 g, 2.71 mmol) in MeOH (50 mL) was stirred at room temperature for 16 h. The resulting mixture was concentrated under reduced pressure. The residue was purified by flash column chromatography with 0-60% EtOAc in PE to afford a 1:1 mixture of tert-butyl ((lR,2S)-2-((S)-2-hydroxypropoxy)-5-methyl-2,3-dihydro-lH-inden-l- yl)carbamate and tert-butyl ((lS,2R)-2-((S)-2-hydroxypropoxy)-5-methyl-2,3-dihydro-lH- inden-l-yl)carbamate (1.48 g, 17%) as a white solid. MS ESI calculated for C18H27NO4 [M+H]⁺, 322.19; found, 322.10.

Step-7:

[1244] To a stirred 1:1 mixture of tert-butyl ((lR,2S)-2-((S)-2-hydroxypropoxy)-5-methyl- 2,3-dihydro-lH-inden-l-yl)carbamate and tert-butyl ((lS,2R)-2-((S)-2-hydroxypropoxy)-5- methyl-2,3-dihydro-lH-inden-l-yl)carbamate (1.48 g, 4.61 mmol) and EtaN (2.33 g, 23.03 mmol) in DCM (15 mL) was added methanesulfonic anhydride (3.21 g, 18.42 mmol) at room temperature. The resulting mixture was stirred at room temperature for 1 h. The reaction mixture was basified with NaHCCh (sat.) to pH 8 and extracted with DCM. The combined organic layers were washed with brine, dried over anhydrous Na2SO4. After filtration, the filtrate was concentrated under reduced pressure. Then the residue was dissolved in DCM (15 mL) and trifluoroacetic acid (5 mL) at room temperature. The resulting mixture was stirred at room temperature for 1 h. The resulting mixture was concentrated under vacuum. Then the residue was dissolved in acetonitrile (10 mL), 1,2,2,6,6-pentamethylpiperidine (2.15 g, 13.82 mmol) was added to the mixture at room temperature. Then the mixture was heated at 80 °C for 16 h with stirring. The resulting mixture was concentrated under reduced pressure. The residue was purified by reverse phase flash column chromatography with 5% ~ 15% MeCN in water (0.1% FA) and further purified by Prep- Achiral SFC with the following conditions: [Column: YMC-Actus Triart Diol-HILIC 3*25 cm, 5 pm; Mobile Phase A: CO2, Mobile Phase B: IPA (20 mM NH3); Flow rate: 75 mL/min; Gradient: isocratic 13% B; Column Temperature (°C): 35; Back Pressure(bar): 100; Wave Length: 220 nm; RTl(min): 4.87;

RT2(min): 6.17; Sample Solvent: MEOH] to afford (3R,4aR,9aS)-3,7-dimethyl-2,3,4,4a,9,9a- hexahydroindeno[2,l-b][l,4]oxazine (350 mg, 38%) as a white solid with retention time at

4.87 minute.

[1245] The achiral separation also afford (3R,4aS,9aR)-3,7-dimethyl-2,3,4,4a,9,9a- hexahydroindeno[2,l-b][l,4]oxazine (A53) (245 mg, 26%) as a yellow oil with retention time at 6.17 minute. MS ESI calculated for C13H17NO [M+H]⁺, 204.13; found, 204.15. ¹H NMR (400 MHz, DMSO- fc) 8 (ppm) 7.19 (d, J = 7.6 Hz, 1H), 7.05 (s, 1H), 6.98 (d, J = 7.6 Hz, 1H), 4.20 - 4.14 (m, 1H), 3.96 (d, J = 5.2 Hz, 1H), 3.53 - 3.49 (m, 1H), 3.29 - 3.13 (m, 2H),

2.88 - 2.65 (m, 2H), 2.27 (s, 3H), 0.85 (d, J = 6.4 Hz, 3H). Absolute stereochemistry was determined by NOESY.

Intermediate A54: (2R,4aR,10bS)-8-chloro-2-methyl-2,3,4a,5,6,10b-hexahydro-lH- naphtho[2, 1 -b] [ 1 ,4] oxazine

Step-1:

[1246] To a stirred solution of 6-chloro-3,4-dihydronaphthalen-l(2H)-one (15.00 g, 83.04 mmol) in ethyl acetate (300 mL) was added CuB (27.82 g, 124.57 mmol) in portions at room temperature under nitrogen atmosphere. The resulting mixture was stirred at 80 °C for 3 h under nitrogen atmosphere. The resulting mixture was filtered, and the filter cake was washed with ethyl acetate. The filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-30% ethyl acetate in petroleum ether to afford a 1:1 mixture of (S)-2-bromo-6-chloro-3,4-dihydronaphthalen- l(2H)-one and (R)-2-bromo-6-chloro-3,4-dihydronaphthalen-l(2H)-one (17.10 g, 79%) as a light yellow solid. MS ESI calculated for CwHsBrClO [M+H]⁺, 258.94, 260.94; found, 259.00, 261.00.

Step-2:

[1247] To a stirred solution of a 1:1 mixture of (S)-2-bromo-6-chloro-3,4- dihydronaphthalen- 1 (2H)-one and (R)-2-bromo-6-chloro-3 ,4-dihydronaphthalen- 1 (2H)-one (17.10 g, 65.89 mmol) in MeOH (170 mL) was added NaBH₄ (2.49 g, 65.82 mmol) in portions at 0 °C under nitrogen atmosphere. The resulting mixture was stirred at 0 °C for 1 h under nitrogen atmosphere. The reaction was quenched with water, and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous NaiSCL. After filtration, the filtrate was concentrated under reduced pressure. This resulted in a 1:1 mixture of (lR,2S)-2-bromo-6-chloro-l,2,3,4-tetrahydronaphthalen-l-ol and (lS,2R)-2- bromo-6-chloro-l,2,3,4-tetrahydronaphthalen-l-ol (17.10 g, crude) as a light yellow solid. MS ESI calculated for CioHioBrClO [M+H]⁺, 260.96, 262.96; found, 261.05, 263.05.

Step-3:

[1248] To a stirred solution of a 1:1 mixture of (lR,2S)-2-bromo-6-chloro-l,2,3,4- tetrahydronaphthalen- 1 -ol and ( 1 S,2R)-2-bromo-6-chloro- 1,2,3 ,4-tetrahydronaphthalen- 1 -ol (17.10 g, 65.38 mmol) in acetonitrile (170 mL) was added cone. H2SO4 (12.82 g, 130.76 mmol) dropwise at 0 °C. The resulting mixture was stirred at 50 °C for 1 h. Then water (170 mL) was added to the mixture at 50 °C. The mixture was stirred at 80 °C for 16 h. The mixture was cooled to room temperature, filtered, and the filter cake was washed with CH2CI2. The filtrate was extracted with CH2CI2. The aqueous layer was basified with NaOH (aq., 20%) to PH 12 and extracted with CH2CI2. The combined organic layers were washed with brine, dried over anhydrous Na2SO4. After filtration, the filtrate was concentrated under reduced pressure. This resulted in a 1:1 mixture of (lR,2S)-l-amino-6-chloro-l, 2,3,4- tetrahydronaphthalen-2-ol and ( 1 S,2R)- 1 -amino-6-chloro- 1 ,2,3 ,4-tetrahydronaphthalen-2-ol (9.1 g, crude) as a white solid. MS ESI calculated for C10H12CINO [M+H]⁺, 198.06; found, 198.00.

Step-4:

[1249] To a stirred solution of a 1:1 mixture of (lR,2S)-l-amino-6-chloro-l,2,3,4- tetrahydronaphthalen-2-ol and ( 1 S,2R)- 1 -amino-6-chloro- 1 ,2,3 ,4-tetrahydronaphthalen-2-ol (9.10 g, 46.04 mmol) and EtsN (9.32 g, 92.08 mmol) in methanol (91 mL) was added BOC2O (10.05 g, 46.04 mmol) dropwise at 0 °C under nitrogen atmosphere. The resulting mixture was stirred at room temperature for 6 h. The reaction was quenched by the addition of water. The resulting mixture was extracted with CH2CI2. The combined organic layers were washed with brine, dried over anhydrous Na2SO4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-20% MeOH in CH2CI2 to afford a 1:1 mixture of tert-butyl ((lR,2S)-6-chloro-2-hydroxy- l,2,3,4-tetrahydronaphthalen-l-yl)carbamate and tert-butyl ((lS,2R)-6-chloro-2-hydroxy- l,2,3,4-tetrahydronaphthalen-l-yl)carbamate (11.3 g, 82%) as an orange oil. MS ESI calculated for C15H20CINO3 [M+H]⁺, 298.11; found, 298.15.

Step-5:

[1250] To a stirred solution of a 1:1 mixture of tert-butyl ((lR,2S)-6-chloro-2-hydroxy- l,2,3,4-tetrahydronaphthalen-l-yl)carbamate and tert-butyl ((lS,2R)-6-chloro-2-hydroxy- l,2,3,4-tetrahydronaphthalen-l-yl)carbamate (8.80 g, 29.55 mmol) and NaOH (8.27 g, 206.86 mmol) in DCM (83 mL) were added (Bu4N)HSC>4 (2.01 g, 5.91 mmol) and (4S)-4-methyl- 1, 3, 2- -6-di oxathiolane-2, 2-dione (supplier: Suzhou spark Biotechnology Co., Ltd. CAS# 174953-30-1) (5.31 g, 38.42 mmol) at room temperature under nitrogen atmosphere. The mixture was stirred at room temperature for 2 h. The resulting mixture was concentrated under reduced pressure. The residue was dissolved in water and neutralized with HC1 (aq) to PH~7. The resulting mixture was extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous NazSCL. After filtration, the filtrate was concentrated under reduced pressure. The residue was dissolved in 2-methoxy-2- methylpropane (350 mL) and H2O (12 mL), then TsOH (3.05 g, 17.73 mmol) was added at room temperature. The mixture was stirred at 40 °C for 4 h. The resulting mixture was quenched with water and basified with NaHCCh (sat.). The resulting mixture was extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous NaiSCL. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-50% ethyl acetate in petroleum ether to afford a 1:1 mixture of tert-butyl ((lR,2S)-6-chloro-2-((S)-2- hydroxypropoxy)-l,2,3,4-tetrahydronaphthalen-l-yl)carbamate and tert-butyl ((lS,2R)-6- chloro-2-((S)-2-hydroxypropoxy)-l,2,3,4-tetrahydronaphthalen-l-yl)carbamate (6.4 g, 61%) as a white solid. MS ESI calculated for C13H18CINO2 [M+H]⁺, 256.10; found, 256.00.

Step-6:

[1251] To a stirred solution of a 1:1 mixture of tert-butyl ((lR,2S)-6-chloro-2-((S)-2- hydroxypropoxy)-l,2,3,4-tetrahydronaphthalen-l-yl)carbamate and tert-butyl ((lS,2R)-6- chloro-2-((S)-2-hydroxypropoxy)-l,2,3,4-tetrahydronaphthalen-l-yl)carbamate (6.63 g, 18.64 mmol) in toluene (150 mL) was added 2-(tributyl-k⁵-phosphaneylidene)acetonitrile (CAS No. 157141-27-0) (9.00 g, 37.29 mmol) at room temperature under nitrogen atmosphere. The resulting mixture was stirred at 110 °C for 2 h. The mixture was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-30% ethyl acetate in petroleum ether to afford a 1:1 mixture of tert-butyl (2R,4aS,10bR)-8-chloro- 2-methyl-2,3,4a,5,6,10b-hexahydro-lH-naphtho[2,l-b][l,4]oxazine-l-carboxylate and tertbutyl (2R,4aR,10bS)-8-chloro-2-methyl-2,3,4a,5,6,10b-hexahydro-lH-naphtho[2,l- b][ 1,4] oxazine- 1 -carboxylate (5.53 g, 88%) as a light yellow oil. MS ESI calculated for C18H24CINO3 [M+H]⁺, 338.14; found, 338.05.

Step-7:

[1252] To a stirred solution of 1:1 mixture of tert-butyl (2R,4aS,10bR)-8-chloro-2-methyl- 2,3 ,4a, 5 ,6,1 Ob-hexahydro- lH-naphtho[2, 1 -b] [ 1 ,4]oxazine- 1 -carboxylate and tert-butyl (2R,4aR,10bS)-8-chloro-2-methyl-2,3,4a,5,6,10b-hexahydro-lH-naphtho[2,l-b][l,4]oxazine- 1-carboxylate (5.53 g, 16.37 mmol) in DCM (52 mL) was added trifluoroacetic acid (17.3 mL) at room temperature. The resulting mixture was stirred at room temperature for 2 h. The resulting mixture was concentrated under reduced pressure. The residue was purified by reversed-phase column chromatography with 5% to 25% MeCN in Water (0.1% TFA) to afford a 1:1 mixture of (2R,4aS,10bR)-8-chloro-2-methyl-2,3,4a,5,6,10b-hexahydro-lH- naphtho[2,l-b][l,4]oxazine and (2R,4aR,10bS)-8-chloro-2-methyl-2,3,4a,5,6,10b-hexahydro- lH-naphtho[2,l-b][l,4]oxazine (3.7 g) as a white solid. The mixture was purified by Prep- Achiral-SFC with the following conditions [Column: GreenSep Basic 3*15 cm, 5 p; Mobile Phase A: CO2, Mobile Phase B: MeOH(20mM NH3.M); Flow rate: 75 mL/min; Gradient: isocratic 15% B; Column Temperature(25 °C): 35; Back Pressure(bar): 100; Wave Length: 220 nm; RTl(min): 2.13; RT2(min): 3.60; Sample Solvent: MeOH] to afford (2R,4aS,10bR)- 8-chloro-2-methyl-2,3,4a,5,6,10b-hexahydro-lH-naphtho[2,l-b][l,4]oxazine (1.0 g, 25% yield) as a light yellow solid with the first peak on Achiral SFC. MS ESI calculated for C13H16CINO [M+H]⁺, 238.09; found, 238.10. NMR (400 MHz, DMSO- ₆) 8 7.71 (d, J = 8.4 Hz, 1H), 7.24 (dd, J = 8.3, 2.3 Hz, 1H), 7.15 (d, J= 2.3 Hz, 1H), 3.94 - 3.78 (m, 2H), 3.61 (dd, J= 10.8, 3.2 Hz, 1H), 3.12 (t, J = 10.6 Hz, 1H), 2.91 - 2.79 (m, 1H), 2.63 - 2.45 (m, 2H), 2.01 - 1.91 (m, 1H), 1.88 - 1.75 (m, 1H), 0.87 (d, J = 6.4 Hz, 3H).

[1253] The separation also afford (2R,4aR,10bS)-8-chloro-2-methyl-2,3,4a,5,6,10b- hexahydro- lH-naphtho [2, 1-b] [ 1,4] oxazine (A54) (884 mg, 22%) as a white solid with the second peak on Achiral SFC. MS ESI calculated for C13H16CINO [M+H]⁺, 238.09; found, 238.10. ¹H NMR (400 MHz, DMSO-d₆) 87.49 - 7.40 (m, 1H), 7.38 - 7.26 (m, 2H), 4.48 - 3.99 (m, 2H), 3.92 - 3.57 (m, 1H), 3.48 - 3.36 (m, 1H), 3.13 - 2.66 (m, 3H), 2.65 - 2.52 (m, 1H), 1.76 - 1.58 (m, 1H), 1.18 - 0.98 (m, 3H). Absolute stereochemistry was determined by NOESY.

Intermediate A55: (2R,4aR,10bS)-8-fluoro-2-methyl-2,3,4a,5,6,10b-hexahydro-lH- naphtho[2, 1 -b] [ 1 ,4] oxazine

Step-1:

[1254] To a mixture of 6-fhioro-3,4-dihydronaphthalen-l(2H)-one (30.50 g, 185.77 mmol) in Diethyl ether (300 mL) was dropwise added B (9.5 mL, 185.77 mmol) at 0 °C under nitrogen atmosphere. The mixture was stirred at room temperature for 1 h. The reaction mixture was quenched by saturated NaS2Os aq. and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under vacuum. The resulting residue was purified by normal phase flash chromatography using a 330 g silica gel column eluted with 0-30% ethyl acetate in petroleum ether within 20 min to afford a 1:1 mixture of (R)-2-bromo-6-fluoro-3,4- dihydronaphthalen- 1 (2H)-one and (S)-2-bromo-6-fluoro-3,4-dihydronaphthalen-l (2H)-one (33.10 g, 73%) as a yellow oil. MS ESI calculated for CioH₈BrFO [M+H]⁺, 242.97; found, 242.85.

Step-2:

[1255] To a 1 : 1 mixture of (R)-2-bromo-6-fluoro-3,4-dihydronaphthalen- 1 (2H)-one and (S)-2-bromo-6-fluoro-3,4-dihydronaphthalen-l(2H)-one (10 g, 41.14 mmol) in EtOH (100 mL) was added NaBIL (0.78 g, 20.57 mmol) in portions af 0 °C. The mixture was stirred at room temperature for 1 h. The reaction mixture was quenched slowly by water at 0 °C and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under vacuum to afford a 1:1 mixture of ( 1 R,2S)-2-bromo-6-fluoro- 1 ,2,3,4-tetrahydronaphthalen- 1 -ol and ( 1 S,2R)-2-bromo-6-fluoro- 1,2,3,4-tetrahydronaphthalen-l-ol (9.30 g, 93% yield) as a white solid. MS ESI calculated for CioHioBrFO [M+H]⁺, 244.99, 246.99; found, 245.00, 247.00.

Step-3:

[1256] To a 1 : 1 mixture of 1 : 1 mixture of (lR,2S)-2-bromo-6-fluoro-l ,2,3,4- tetrahydronaphthalen- 1 -ol and ( 1 S,2R)-2-bromo-6-fluoro- 1 ,2,3 ,4-tetrahydronaphthalen- 1 -ol (9.10 g, 37.13 mmol) in ACN (90 mL) was slowly added H2SO4 (7.28 g, 74.26 mmol) at 0 °C. The mixture was stirred at 50 °C for 1 h. Then H2O (90 mL) was added to the mixture, the mixture was stirred at 80 °C for 16 h. The mixture was concentrated under vacuum. The residue was was basified with NaOH (2 M) to pH ~8 and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under vacuum to afford a 1:1 mixture of (lS,2R)-l-amino-6-fluoro- l,2,3,4-tetrahydronaphthalen-2-ol and (lR,2S)-l-amino-6-fluoro-l,2,3,4- tetrahydronaphthalen-2-ol (4.10 g, 43%) as a white solid. MS ESI calculated for C10H12FNO [M+H]⁺, 182.09; found, 182.00.

Step-4:

[1257] To a 1:1 mixture of (lS,2R)-l-amino-6-fluoro-1 ,2,3,4-tetrahydronaphthalen-2-ol and (lR,2S)-l-amino-6-fluoro-l,2,3,4-tetrahydronaphthalen-2-ol (4.10 g, 22.62 mmol) in MeOH (40 mL) were added EtsN (3.43 g, 33.94 mmol) and di-tert-butyl dicarbonate (5.43 g, 24.89 mmol). The mixture was stirred at room temperature for 1 h. The solvents were removed under vacuum. The resulting residue was purified by Combi Flash (Biotage Isolera Prime) using a 80 g silica gel column eluted with 0-70% ethyl acetate in petroleum ether to afford a 1:1 mixture of tert-butyl ((lS,2R)-6-fluoro-2-hydroxy-l,2,3,4-tetrahydronaphthalen- l-yl)carbamate and tert-butyl ((lR,2S)-6-fluoro-2-hydroxy- 1,2,3, 4-tetrahydronaphthalen-l- yl)carbamate (4.70 g, 66%) as a white solid. MS ESI calculated for C15H20FNO3 [M+H]⁺, 282.14; found, 282.15.

Step-5:

[1258] To a 1:1 mixture of tert-butyl ((IS, 2R)-6-fluoro-2-hydroxy-l, 2,3,4- tetrahydronaphthalen-l-yl)carbamate and tert-butyl ((lR,2S)-6-fhioro-2-hydroxy-l,2,3,4- tetrahydronaphthalen-l-yl)carbamate (3.4 g, 12.08 mmol) in DCM (30 mL) were added (4S)- 4-methyl-l, 3, 2-X-6-dioxathiolane-2, 2-dione (2.2 g, 15.92 mmol) (supplier: Suzhou spark Biotechnology Co., Ltd. CAS# 174953-30-1), NaOH (3.4 g, 85.00 mmol) and tetrabutylazanium hydrogen sulfate (0.82 g, 2.41 mmol). The resulting mixture was stirred at room temperature for 1 h. The solvents were removed under vacuum. The residue was diluted with H2O (50 mL), then H2SO4 (7 mL) was added. The resulting mixture was stirred at 80 °C for 16 h. The reaction mixture was basified with NaOH (aq., 4N) to pH 8 and extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SO4. After filtration, the filtrate was concentrated under reduced pressure to afford a 1: 1 mixture of (S)- 1 -(((1 S,2R)- 1 -amino-6-fluoro-l ,2,3,4-tetrahydronaphthalen-2-yl)oxy)propan-2-ol and (S)-l-(((lR,2S)-l-amino-6-fluoro-l,2,3,4-tetrahydronaphthalen-2-yl)oxy)propan-2-ol (2.9 g, 95%) as a yellow oil. MS ESI calculated for C12H16FNO2 [M+H]⁺, 240.13; found, 240.00.

[1259] To a 1:1 mixture of (S)-l-(((lS,2R)-l-amino-6-fluoro-l,2,3,4-tetrahydronaphthalen- 2-yl)oxy)propan-2-ol and (S)-1-(((1R,2S)-1 -amino-6-fluoro- 1 ,2,3 ,4-tetrahydronaphthalen-2- yl)oxy)propan-2-ol (2.1 g, 8.77 mmol) in MeOH (20 mL) were sequentially added EtsN (1.33 g, 13.16 mmol) and di-tert-butyl dicarbonate (1.92 g, 8.77 mmol) at room temperature. The resulting solution was stirred at room temperature for 4 h. The solvents were removed under vacuum. The resulting residue was purified by Combi Flash using a 80 g silica gel column eluted with 0-50% ethyl acetate in petroleum ether to afford a 1:1 mixture of tert-butyl ((IS ,2R)-6-fluoro-2-((S)-2-hydroxypropoxy)- 1 ,2,3 ,4-tetrahydronaphthalen- 1 -yl)carbamate and tert-butyl ((lR,2S)-6-fhioro-2-((S)-2-hydroxypropoxy)-l,2,3,4-tetrahydronaphthalen-l- yl)carbamate (1.75 g, 53%) as a white solid. MS ESI calculated for C18H26FNO4 [M+H]⁺, 340.18; found, 340.10.

Step-7:

[1260] To a 1:1 mixture of tert-butyl ((IS, 2R)-6-fhioro-2-((S)-2-hydroxypropoxy)-l, 2,3,4- tetrahydronaphthalen-l-yl)carbamate and tert-butyl ((lR,2S)-6-fluoro-2-((S)-2- hydroxypropoxy)-l,2,3,4-tetrahydronaphthalen-l-yl)carbamate (1.7 g, 5.00 mmol) in toluene (20 mL) was added 2-(tributyl-A,⁵-phosphaneylidene)acetonitrile (CAS No. 157141-27-0) (2.4 g, 10.55 mmol). The resulting mixture was stirred at 110 °C for 3 h. The solvents were removed under vacuum. The residue was purified by silica gel column chromatography, eluted with PE / EtOAc (4:1) to afford a 1:1 mixture of tert-butyl (2R,4aS,10bR)-8-fluoro-2- methyl-2,3,4a,5,6, 1 Ob-hexahydro- lH-naphtho[2, 1 -b] [1 ,4]oxazine- 1 -carboxylate and tertbutyl (2R,4aR, 10bS)-8-fluoro-2-methyl-2,3,4a,5,6, 1 Ob-hexahydro- lH-naphtho[2, 1- b][ 1,4] oxazine- 1 -carboxylate (1.5 g, 84%) as a yellow oil. MS ESI calculated for C18H24FNO3 [M+H]⁺, 322.17 found, 322.10.

Step-8:

[1261] To a solution of 1: 1 mixture of tert-butyl (2R,4aS,10bR)-8-fhioro-2-methyl- 2,3 ,4a, 5 ,6,1 Ob-hexahydro- lH-naphtho[2, 1 -b] [ 1 ,4]oxazine- 1 -carboxylate and tert-butyl (2R,4aR,10bS)-8-fluoro-2-methyl-2,3,4a,5,6,10b-hexahydro-lH-naphtho[2,l-b][l,4]oxazine- 1-carboxylate (1.5 g, 4.62 mmol) in DCM (15 mL) was added Zinc bromide (2.07 g, 9.24 mmol). The resulting mixture was stirred at 40 °C for 16 h. The mixture was quenched with water and extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SC>4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by reverse phase flash with the 5-35% MeCN in H2O (10 mM NH4HCO3) to afford a 1 :1 mixture of (2R,4aR,10bS)-8-fluoro-2-methyl-2, 3, 4a, 5, 6,1 Ob- hexahydro- 1 H-naphtho [2, 1 -b] [ 1 ,4] oxazine and (2R,4aS, 10bR)-8-fluoro-2-methyl- 2,3,4a,5,6,10b-hexahydro-lH-naphtho[2,l-b][l,4]oxazine (990 mg), which was separated by prep- Achiral SFC with the following conditions: [Column: YMC-Pack Polyamine II 3*25 cm, 5 pm; Mobile Phase A: CO2, Mobile Phase B: MeOH (20 mM NH3); Flow rate: 75 mL/min; Gradient (B%): isocratic 18% B; Column Temperature(°C): 35; Back Pressure(bar): 100; Wave Length: 254 nm; RTl(min): 2.44; RT2(min): 3.34; Sample Solvent: MeOH— HPLC] to afford (2R,4aS,10bR)-8-fluoro-2-methyl-2,3,4a,5,6,10b-hexahydro-lH- naphtho[2,l-b][l,4]oxazine (560 mg, 56%) as a white solid with retention time at 2.44 minute. MS ESI calculated for C13H16FNO [M+H]⁺, 222.12; found, 222.05.

[1262] The separation also afford (2R,4aR,10bS)-8-fluoro-2-methyl-2,3,4a,5,6,10b- hexahydro- lH-naphtho [2, l-b][ 1,4] oxazine (A55) (280 mg, 28%) as a white solid with retention time at 3.34 min. MS ESI calculated for C13H16FNO [M+H]⁺, 222.12; found, 222.05. ¹H NMR (400 MHz, DMSO) 5 7.34 - 7.28 (m, 1H), 7.02 - 6.94 (m, 1H), 6.91 (dd, J = 10.2, 2.8 Hz, 1H), 3.86 - 3.78 (m, 2H), 3.41 (dd, 7= 10.8, 3.2 Hz, 1H), 3.19 (t, J = 10.8 Hz, 1H), 2.98 - 2.87 (m, 1H), 2.87 - 2.83 (m, 1H), 2.82 - 2.70 (m, 1H), 2.66 - 2.53 (m, 1H), 2.26

- 2.03 (m, 1H), 1.57 - 1.46 (m, 1H), 0.87 (d, J = 6.4 Hz, 3H). Absolute stereochemistry was determined by NOESY.

Intermediate A56 isomer 1: (2R,4aR*,llbR*)-2-methyl-9-(trifluoromethyl)-2,3,4a,5,7,llb- hexahydro-lH-benzo[5,6]oxepino[3,4-b][l,4]oxazine isomer 1

Isomer 1 _and

Intermediate A56 isomer 2: (2R,4aR*,l lbR*)-2-methyl-9-(trifluoromethyl)-2,3,4a,5,7,l lb- hexahydro- 1 H-benzo [5, 6] oxepino [3 ,4-b][ 1,4] oxazine isomer 2

Step-1:

[1263] To a stirred solution of (2-bromo-5-(trifluoromethyl)phenyl)methanol (5.00 g, 19.60 mmol) and ethenyltrifluoro-X-4-borane potassium (3.94 g, 29.41 mmol) in 1,4-dioxane (50 mL) and H2O (10 mL) were added K2CO3 (89.4 g, 646.96 mmol) and Pd(dppf)C12-CH2C12 (1.43 g, 1.96 mmol) at room temperature. The resulting mixture was stirred at 100 °C for 1 h under nitrogen atmosphere. The mixture was allowed to cool down to room temperature and concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-30% ethyl acetate in petroleum ether to afford (5- (trifhioromethyl)-2-vinylphenyl)methanol (3.65 g, 89%) as a white solid. MS ESI calculated for C10H9F3O [M+H]⁺, 201.06; found, 201.00. 'H NMR (400 MHz, DMSO-d₆) 6 7.86 - 7.71 (m, 2H), 7.62 - 7.57 (m, 1H), 7.01 (dd, J = 17.2, 11.2 Hz, 1H), 5.88 (dd, J= 17.6, 1.2 Hz, 1H), 5.56 - 5.31 (m, 2H), 4.64 (d, J = 5.6 Hz, 2H)

Step-2:

[1264] To a solution of (5-(trifluoromethyl)-2-vinylphenyl)methanol (6.85 g, 33.88 mmol) in THF (70 mL) was added NaH (1.63 g, 40.65 mmol, 60% in mineral oil) at 0 °C, the mixture was stirred at 0 °C for 30 min. This was followed by the addition of 3-bromoprop-l- ene (4.92 g, 40.65 mmol) dropwise at room temperature. The resulting mixture was stirred at room temperature for 1 h. The reaction was quenched with water at 0 °C and extracted with EtOAc. The organic layer was dried over anhydrous Na2SO4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-20% ethyl acetate in petroleum ether to afford 2- ((allyloxy)methyl)-4-(trifluoromethyl)-l-vinylbenzene (7.66 g, 93%) as a yellow liquid. MS ESI calculated for C13H13F3O [M+H]⁺, 243.09; found, 243.00. ’H NMR (400 MHz, DMSO- d₆) 8 7.90 - 7.73 (m, 1H), 7.73 - 7.60 (m, 2H), 7.01 (dd, J= 17.6, 11.2 Hz, 1H), 6.06 - 5.86 (m, 2H), 5.51 (dd, J = 11.2, 1.2 Hz, 1H), 5.32 - 5.26 (m, 1H), 5.20 - 5.16 (m, 1H), 4.62 (s, 2H), 4.06 (dt, J = 5.2, 1 .6 Hz, 2H).

Step-3:

[1265] A solution of 2-((allyloxy)methyI)-4-(trifluoromethyI)-l-vinylbenzene (3.44 g, 14.20 mmol) and Grubbs 2nd (3.01 g, 3.55 mmol) in DCM (35 mL) was stirred at room temperature for 2 h under nitrogen atmosphere. The resulting mixture was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-20% ethyl acetate in petroleum ether to afford 8-(trifhioromethyl)-l,3- dihydrobenzo[c]oxepine (2.55 g, 81%) as a brown solid. MS ESI calculated for C11H9F3O [M+H]⁺, 215.06; found, 215.05. 'H NMR (400 MHz, DMSO-d₆) 5 7.71 - 7.55 (m, 2H), 7.52 (d, J= 8.0 Hz, 1H), 6.60 - 6.56 (m, 1H), 6.11 (dt, J= 12.4, 2.8 Hz, 1H), 4.70 (s, 2H), 4.54 (t, J = 2.8 Hz, 2H).

Step-4:

[1266] To a solution of 8-(trifluoromethyl)-l,3-dihydrobenzo[c]oxepine (1.23 g, 5.74 mmol) in DMSO (15 mL) and H2O (3 mL) was added NBS (1.02 g, 5.74 mmol) at 0 °C. The mixture was stirred at 0 °C for 1 h. The resulting mixture was quenched with water and extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous NazSCh. After filtration, the filtrate was concentrated under reduced pressure to afford a 1:1 mixture of (4S,5S)-4-bromo-8-(trifluoromethyl)-l,3,4,5- tetrahydrobenzo[c]oxepin-5-ol and (4R,5R)-4-bromo-8-(trifhioromethyl)- 1 ,3,4,5- tetrahydrobenzo[c]oxepin-5-ol (1.66 g, crude) as a brown oil. MS ESI calculated for CnHioBrFsCh [M+H]⁺, 310.98, 312.98; found, 311.00, 313.00.

Step-5:

[1267] A solution of a 1:1 mixture of (4S,5S)-4-bromo-8-(trifluoromethyl)-l, 3,4,5- tetrahydrobenzo[c]oxepin-5-ol and (4R,5R)-4-bromo-8-(trifhioromethyl)- 1 ,3,4,5- tetrahydrobenzo[c]oxepin-5-ol (1.66 g, 5.33 mmol) and Ammonium hydroxide (28% in water) (1.61 g, 45.89 mmol) in MeOH (17 mL) was stirred at room temperature for 2 days under nitrogen atmosphere. The resulting mixture was filtered, the filter cake was washed with MeOH (17 mL). The filtrate was concentrated under reduced pressure to afford a 1:1 mixture of (4S,5R)-5-amino-8-(trifluoromethyl)-l,3,4,5-tetrahydrobenzo[c]oxepin-4-ol and (4R,5S)-5-amino-8-(trifluoromethyl)-l,3,4,5-tetrahydrobenzo[c]oxepin-4-ol (870 mg, 62%) as a white solid. MS ESI calculated for C11H12F3NO2 [M+H]⁺, 248.08; found, 248.10. 'H NMR (400 MHz, DMSO-Jg) 6 7.77 (d, J= 8.0 Hz, 1H), 7.66 - 7.62 (m, 1H), 7.56 - 7.54 (m, 1H), 5.17 (s, 1H), 4.83 (d, J= 13.6 Hz, 1H), 4.61 (d, J= 13.6 Hz, 1H), 4.23 - 3.99 (m, 2H), 3.69 - 3.63 (m, 1H), 3.30 - 3.24 (m, 1H).

Step-6

[1268] To a stirred solution of a 1 : 1 mixture of (4S,5R)-5-amino-8-(trifluoromethyl)- l,3,4,5-tetrahydrobenzo[c]oxepin-4-ol and (4R,5S)-5-amino-8-(trifluoromethyl)-l, 3,4,5- tetrahydrobenzo[c]oxepin-4-ol (5.30 g, 21.43 mmol) and TEA (2.82 g, 27.87 mmol) in DCM (100 mL) was added benzoyl chloride (3.01 g, 21.43 mmol) dropwise at 0 °C under nitrogen atmosphere. The resulting mixture was stirred at room temperature for 2 h. The resulting mixture was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-10% methanol in dichloromethane to afford a 1:1 mixture of N-((4S,5R)-4-hydroxy-8-(trifluoromethyl)-l,3,4,5-tetrahydrobenzo[c]oxepin-5- yl)benzamide and N-((4R,5S)-4-hydroxy-8-(trifluoromethyl)-l, 3,4,5- tetrahydrobenzo[c]oxepin-5-yl)benzamide (5.10 g, 65%) as a white solid. MS ESI calculated for C18H16F3NO3 [M+H]⁺, 352.11; found, 352.10.

Step-7:

[1269] To a stirred solution of a 1:1 mixture of N-((4S,5R)-4-hydroxy-8-(trifluoromethyl)- 1 ,3,4,5-tetrahydrobenzo[c]oxepin-5-yl)benzamide and N-((4R,5S)-4-hydroxy-8- (trifluoromethyl)-l,3,4,5-tetrahydrobenzo[c]oxepin-5-yl)benzamide (620 mg, 1.76 mmol) in DCM (12 mL) was added SOCI2 (419 mg, 3.53 mmol) dropwise at 0 °C under nitrogen atmosphere. The resulting mixture was stirred at room temperature for 16 h. The resulting mixture was concentrated under reduced pressure. The residue was diluted with NaHCCh (aq.) and extracted with CH2CI2. The organic layer was dried over anhydrous Na2SC>4. After filtration, the filtrate was concentrated under reduced pressure to afford a 1: 1 mixture of (3aS,10bS)-2-phenyl-8-(trifluoromethyl)-3a,4,6,10b-tetrahydrobenzo[5,6]oxepino[4,3- d]oxazole and (3aR,10bR)-2-phenyl-8-(trifluoromethyl)-3a,4,6,10b- tetrahydrobenzo[5,6]oxepino[4,3-d]oxazole (447 mg, 69%) as a yellow solid. MS ESI calculated for C18H14F3NO2 [M+H]⁺, 334.10; found, 334.15.

Step-8:

[1270] To a stirred solution of a 1:1 mixture of (3aS,10bS)-2-phenyl-8-(trifluoromethyl)- 3a,4,6,10b-tetrahydrobenzo[5,6]oxepino[4,3-d]oxazole and (3aR,10bR)-2-phenyl-8- (trifluoromethyl)-3a,4,6,10b-tetrahydrobenzo[5,6]oxepino[4,3-d]oxazole (518 mg, 1.55 mmol) in 1,4-dioxane (3 mL) was added HC1 (6 mL) at room temperature. The resulting mixture was stirred at 100 °C for 16 h. The mixture was allowed to cool down to room temperature and partitioned between CH2CI2 and water. The mixture was extracted with CH2CI2. The aqueous phase was collected and basified with NaOH to pH 10. The aqueous layer was then extracted with CH2CI2. The organic layer was dried over anhydrous Na2SC>4.

After filtration, the filtrate was concentrated under reduced pressure to afford a 1: 1 mixture of (4S,5S)-5-amino-8-(trifhioromethyl)-l,3,4,5-tetrahydrobenzo[c]oxepin-4-ol and (4R,5R)-5- amino-8-(trifluoromethyl)-l,3,4,5-tetrahydrobenzo[c]oxepin-4-ol (300 mg, 78%) as a white solid. MS ESI calculated for C11H12F3NO2 [M+H]⁺, 248.08; found, 248.05.

Step-9:

[1271] To a stirred solution of a 1:1 mixture of (4S,5S)-5-amino-8-(trifluoromethyl)- l,3,4,5-tetrahydrobenzo[c]oxepin-4-ol and (4R,5R)-5-amino-8-(trifluoromethyl)-l,3,4,5- tetrahydrobenzo[c]oxepin-4-ol (1.40 g, 5.66 mmol) and EtsN (1.15 g, 11.32 mmol) in MeOH (20 mL) was added BOC2O (1.61 g, 7.36 mmol) dropwise at 0 °C. The resulting mixture was stirred at room temperature for 2 h. The mixture was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-60% ethyl acetate in petroleum ether to afford a 1 : 1 mixture of tert-butyl ((4S,5S)-4-hydroxy-8- (trifluoromethyl)-l,3,4,5-tetrahydrobenzo[c]oxepin-5-yl)carbamate and tert-butyl ((4R,5R)-4- hydroxy-8-(trifhioromethyl)-l,3,4,5-tetrahydrobenzo[c]oxepin-5-yl)carbamate (1.71 g, 85%) as a white solid. MS ESI calculated for C16H20F3NO4 [M+H]⁺, 348.13; found, 348.10.

Step- 10:

[1272] To a stirred solution of a 1:1 mixture of tert-butyl ((4S,5S)-4-hydroxy-8- (trifhioromethyl)-l,3,4,5-tetrahydrobenzo[c]oxepin-5-yl)carbamate and tert-butyl ((4R,5R)-4- hydroxy-8-(trifluoromethyl)-l,3,4,5-tetrahydrobenzo[c]oxepin-5-yl)carbamate (1.21 g, 3.48 mmol) in DCM (12 mL) were added NaOH (975 mg, 24.38 mmol) and (S)-4-methyl- 1,3,2- dioxathiolane 2,2-dioxide (supplier: Suzhou spark Biotechnology Co., Ltd. CAS# 174953- 30-1) (625 mg, 4.52 mmol) at room temperature. The resulting mixture was stirred at room temperature for 4 h. The resulting mixture was concentrated under reduced pressure. The residue was quenched with water. The mixture was neutralized with HC1 (cone.) to pH 7. The resulting mixture was extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous NaiSCL. After filtration, the filtrate was concentrated under reduced pressure. The residue was dissolved in 2-methoxy-2-methylpropane (51 mL) and H2O (1.7 mL), this was followed by the addition of TsOH (359 mg, 2.09 mmol) and dioxane (14.4 mL) at room temperature. The resulting mixture was stirred at 40 °C for 2 h under nitrogen atmosphere. The resulting mixture was quenched with water and neutralized by NaHCCh (aq.). to pH 8. The resulting mixture was extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SO4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-60% ethyl acetate in petroleum ether to afford a 1:1 mixture of tert-butyl ((4S,5S)-4-((S)-2-hydroxypropoxy)-8-(trifluoromethyl)-l, 3,4,5- tetrahydrobenzo[c]oxepin-5-yl)carbamate and tert-butyl ((4R,5R)-4-((S)-2-hydroxypropoxy)- 8-(trifluoromethyl)-l,3,4,5-tetrahydrobenzo[c]oxepin-5-yl)carbamate (1.01 g, 67%) as a white solid. MS ESI calculated for C19H26F3NO5 [M+H]⁺, 406.18; found, 406.15.

Step-11:

[1273] A solution of a 1:1 mixture of tert-butyl ((4S,5S)-4-((S)-2-hydroxypropoxy)-8- (trifhioromethyl)-l,3,4,5-tetrahydrobenzo[c]oxepin-5-yl)carbamate and tert-butyl ((4R,5R)-4- ((S)-2-hydroxypropoxy)-8-(trifluoromethyl)-l,3,4,5-tetrahydrobenzo[c]oxepin-5- yl)carbamate (273 mg, 0.67 mmol) and 2-(tributyl-X⁵-phosphaneylidene)acetonitrile (CAS No. 157141-27-0) (325 mg, 1.34 mmol) in toluene (5 mL) was stirred at 110 °C for 16 h under nitrogen atmosphere. The mixture was allowed to cool down to room temperature and concentrated under vacuum. The residue was purified by silica gel column chromatography, eluted with 0-40% ethyl acetate in petroleum ether to afford a 1:1 mixture of tert-butyl (2R,4aS , 11 bS)-2-methyl-9-(trifhioromethyl)-2,3 ,4a, 5 ,7,11 b-hexahydro- 1 H- benzo[5,6]oxepino[3,4-b][l,4]oxazine-l-carboxylate and tert-butyl (2R,4aR,l lbR)-2-methyl- 9-(trifluoromethyl)-2,3,4a,5,7,llb-hexahydro-lH-benzo[5,6]oxepino[3,4-b][l,4]oxazine-l- carboxylate (200 mg, 74%) as a white solid. MS ESI calculated for C19H24F3NO4 [M+H]⁺, 388.18; found, 388.15.

Step- 12:

A56 isomer 2

[1274] To a solution of tert-butyl (2RS,4R,7RS)-4-methyl-13-(trifluoromethyl)-6,9-dioxa- 3-azatricyclo[9.4.0.0^A{2,7}]pentadeca-l(15),ll,13-triene-3-carboxylate (627 mg, 1.61 mmol) in DCM (6 mL) was added TFA (2 mL). The mixture was stirred at room temperature for 1 h. The resulting mixture was concentrated under vacuum. The residue was basified with NaHCCh (aq.) and extracted with EtOAc. The organic layer was dried over anhydrous Na2SC>4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by Prep-HPLC with the following conditions [Column: Xcelect CSH F-pheny OBD Column 19*250 mm, 5m; Mobile Phase A: Water (0.05% TFA), Mobile Phase B: ACN; Flow rate: 25 mL/min; Gradient: 10% B to 20% B in 10 min; Wave Length: 254/220 nm; RTl(min): 9.0; RT2(min): 9.5] to afford (2R,4aR*,llbR*)-2-methyl-9-(trifluoromethyl)- 2,3,4a,5,7,l lb-hexahydro-lH-benzo[5,6]oxepino[3,4-b][l,4]oxazine (A56, isomer 1) (177 mg) as a white solid with the first peak on HPLC. MS ESI calculated for C14H16F3NO2 [M+H]⁺, 288.11; found, 288.10. 'H NMR (400 MHz, DMSO-d₆) 5 7.65 - 7.54 (m, 3H), 4.85 (d, J = 13.2 Hz, 1H), 4.77 - 4.64 (m, 2H), 4.27 (d, J= 3.2 Hz, 1H), 3.91 - 3.84 (m, 1H), 3.78 - 3.72 (m, 1H), 3.46 and 3.43 (d, J = 4.0 Hz, 1H), 3.37 (d, J= 10.8 Hz, 1H), 3.08 - 2.99 (m, 1H), 2.55 - 2.52 (m, 1H), 0.93 (d, J = 6.4 Hz, 3H). Absolute stereochemistry was not determined.

[1275] The separation also afford (2R,4aR*,llbR*)-2-methyl-9-(trifluoromethyl)- 2,3,4a,5,7,l lb-hexahydro-lH-benzo[5,6]oxepino[3,4-b][l,4]oxazine (A56, isomer 2) (121 mg) as a light yellow solid with the second peak on HPLC. MS ESI calculated for C14H16F3NO2 [M+H]⁺, 288.11; found, 288.10. 'H NMR (400 MHz, DMSO- ) 87.90 (d, J = 8.0 Hz, 1H), 7.72 - 7.60 (m, 1H), 7.56 - 7.52 (m, 1H), 4.84 - 4.78 (m, 1H), 4.72 - 4.65 (m, 1H), 4.37 (s, 1H), 3.95 and 3.92 (d, J= 3.6 Hz, 1H), 3.86 (q, J = 3.6 Hz, 1H), 3.80 - 3.66 (m, 2H), 3.14 (t, J = 10.0 Hz, 1H), 3.08 - 2.97 (m, 2H), 0.94 (d, J = 5.6 Hz, 3H). Absolute stereochemistry was not determined.

Intermediate A57: 2:2: 1:1 mixture of rel-(2R,4aS,10bR)-8-(difluoromethoxy)-2-methyl- l,3,4,4a,5,10b-hexahydro-2H-chromeno[4,3-b]pyridine isomer 1 and rel-(2R,4aS,10bR)-8- (difluoromethoxy)-2-methyl- 1 ,3, 4, 4a, 5, 10b-hexahydro-2H-chromeno[4,3-b]pyridine isomer 2 and rel-(2R,4aS , 10bR)-8-(difluoromethoxy)-2-methyl- 1 ,3 ,4, 4a, 5, 10b-hexahydro-2H- chromeno[4,3-b]pyridine isomer 3 and rel-(2R,4aS,10bR)-8-(difluoromethoxy)-2-methyl- l,3,4,4a,5,10b-hexahydro-2H-chromeno[4,3-b]pyridine isomer 4

A57

Step-1:

[1276] To a stirred solution of (2,4-dimethoxyphenyl)boronic acid (10 g, 54.95 mmol) and methyl 2-chloro-6-methylnicotinate (10.20 g, 54.95 mmol) in 1,4-dioxane (100 mL) and H2O (10 mL) were added Pd(dppf)C12 (4.02 g, 5.49 mmol) and K2CO3 (22.78 g, 164.85 mmol) at room temperature under nitrogen atmosphere. The resulting mixture was stirred at 100 °C for 16 h under nitrogen atmosphere. The resulting mixture was quenched with water. The resulting mixture was extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SC>4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with PE / EtOAc (1:1) to afford methyl 2-(2,4-dimethoxyphenyl)-6-methylnicotinate (12 g, 72%) as a yellow solid. MS ESI calculated for C16H17NO4 [M+H]⁺, 288.12; found, 288.10.

Step-2:

[1277] To a stirred solution of methyl 2-(2,4-dimethoxyphenyl)-6-methylnicotinate (12.9 g, 44.89 mmol) in DCM (130 mL) was added BBn (1 M in DCM) (225 mL, 225 mmol) dropwise at 0 °C. The resulting solution was stirred at 0 °C for 3 h. The reaction was quenched with MeOH at -40 °C. The resulting mixture was concentrated under reduced pressure to afford 8-hydroxy-2-methyl-5H-chromeno[4,3-b]pyridin-5-one (12 g, crude) as a yellow solid. MS ESI calculated for C13H9NO3 [M+H]⁺, 228.06; found, 228.00.

Step-3:

[1278] To a stirred solution of 8-hydroxy-2-methyl-5H-chromeno[4,3-b]pyridin-5-one (10 g, 44.01 mmol) and K2CO3 (9.12 g, 66.02 mmol) in DMF (100 mL) was added sodium 2- chloro-2,2-difluoroacetate (13.42 g, 88.02 mmol) at 0 °C. The resulting mixture was stirred at 100 °C for 2 h. The resulting mixture was quenched with water. The resulting mixture was extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SO4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with PE / EtOAc (1:1) to afford 8-(difhioromethoxy)-2-methyl-5H-chromeno[4,3-b]pyridin-5-one (2.4 g, 18%) as a yellow solid. MS ESI calculated for C14H9F2NO3 [M+H]⁺, 278.06; found, 278.00.

Step-4:

[1279] To a stirred solution of 8-(difhioromethoxy)-2-methyl-5H-chromeno[4,3-b]pyridin- 5-one (2.4 g, 8.65 mmol) in THF (24 mL) was added LiAlFL (0.66 g, 17.31 mmol) in portions at 0 °C. The resulting mixture was stirred at 0 °C for 2 h. The reaction was quenched by the addition of water (0.7 mL) and NaOH (aq. IN) (0.7 mL) at 0 °C. The resulting mixture was filtered, the filter cake was washed with EtOAc. The filterate was collected and extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SO4. After filtration, the filtrate was concentrated under reduced pressure to afford 5- (difluoromethoxy)-2-(3-(hydroxymethyl)-6-methylpyridin-2-yl)phenol (2.2 g, crude) as a yellow solid. MS ESI calculated for C14H13F2NO3 [M+H]⁺, 282.09; found, 282.00.

Step-5:

[1280] To a stirred solution of 5-(difhioromethoxy)-2-(3-(hydroxymethyl)-6- methylpyridin-2-yl)phenol (2.2 g, 7.82 mmol) and PPhs (4.10 g, 15.64 mmol) in THF (22 mL) was added DIAD (3.16 g, 15.64 mmol) dropwise at 0 °C under nitrogen atmosphere. The resulting mixture was stirred at room temperature for 16 h. The reaction was quenched with water. The resulting mixture was extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SO4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with PE / EtOAc (5:1) to afford 8-(difluoromethoxy)-2-methyl-5H- chromeno[4,3-b]pyridine (1.4 g, 62%) as a yellow oil. MS ESI calculated for C14H11F2NO2 [M+H]⁺, 264.08; found, 264.10.

Step-6:

Isomer 1 Isomer 2 Isomer 3 Isomer 4

A57

[1281] To a solution of 8-(difhioromethoxy)-2-methyl-5H-chromeno[4,3-b]pyridine (2.90 g, 11.01 mmol) in i-PrOH (300 mL) and AcOH (30 mL) were added Pd/C (10%, 0.12 g) and Pd(OH)2/C (20%, 0.15 g). The mixture was hydrogenated at 50 °C under 30 psi of hydrogen pressure for 48 h. The mixture was filtered through a Celite pad. The filtrate was concentrated under reduced pressure. The residue was purified by reversed-phase flash column chromatography with 10% ~ 50% MeCN in Water (10 mmol/L NH4HCO3) to afford a 2:2:l:l mixture of rel-(2R,4aS,10bR)-8-(difluoromethoxy)-2-methyl-l,3,4,4a,5,10b- hexahydro-2H-chromeno[4,3-b]pyridine isomer 1 and rel-(2R,4aS,10bR)-8- (difluoromethoxy )-2-methyl- 1 ,3, 4, 4a, 5, 10b-hexahydro-2H-chromeno[4,3-b]pyridine isomer 2 and rel-(2R,4aS , 10bR)-8-(difluoromethoxy)-2-methyl- 1 ,3 ,4, 4a, 5, 10b-hexahydro-2H- chromeno[4,3-b]pyridine isomer 3 and rel-(2R,4aS,10bR)-8-(difluoromethoxy)-2-methyl- l,3,4,4a,5,10b-hexahydro-2H-chromeno[4,3-b]pyridine isomer 4 (A57) (1.3 g, 42%) as a yellow oil. MS ESI calculated for C14H17F2NO2 [M+H]⁺, 270.12; found, 270.05

Intermediate A57 isomer 1: rel-(2R,4aS,10bR)-8-(difluoromethoxy)-2-methyl- l,3,4,4a,5,10b-hexahydro-2H-chromeno[4,3-b]pyridine isomer 1 l^{somer 1} and,

Intermediate A57 isomer 2: rel-(2R,4aS,10bR)-8-(difluoromethoxy)-2-methyl- l,3,4,4a,5,10b-hexahydro-2H-chromeno[4,3-b]pyridine isomer 2 l^{somer 2} and,

Intermediate A57 isomer 3: rel-(2R,4aS,10bR)-8-(difluoromethoxy)-2-methyl- l,3,4,4a,5,10b-hexahydro-2H-chromeno[4,3-b]pyridine isomer 3

Isomer

Intermediate A57 isomer 4: rel-(2R,4aS,10bR)-8-(difluoromethoxy)-2-methyl- l,3,4,4a,5,10b-hexahydro-2H-chromeno[4,3-b]pyridine isomer 4

[1282] 2:2:1:1 mixture of rel-(2R,4aS,10bR)-8-(difluoromethoxy)-2-methyl-l,3,4,4a,5,10b- hexahydro-2H-chromeno[4,3-b]pyridine isomer 1 and rel-(2R,4aS,10bR)-8-

(difluoromethoxy)-2-methyl- 1 ,3, 4, 4a, 5, 10b-hexahydro-2H-chromeno[4,3-b]pyridine isomer 2 and rel-(2R,4aS,10bR)-8-(difluoromethoxy)-2-methyl-l,3,4,4a,5,10b-hexahydro-2H- chromeno[4,3-b]pyridine isomer 3 and rel-(2R,4aS,10bR)-8-(difluoromethoxy)-2-methyl- l,3,4,4a,5,10b-hexahydro-2H-chromeno[4,3-b]pyridine isomer 4 (1.3 g) was separated by Prep-Chiral HPLC with the following conditions: [Column: CHIRALPAK IG, 3*25 cm, 5 pm; Mobile Phase A: CO2, Mobile Phase B: MEOH (0.1% 2M NH3-MEOH); Flow rate: 100 mL/min; Gradient: isocratic 10% B; RT1 (min): 6.7; RT2 (min): 7.9; RT3 (min): 10.5; RT4 (min): 15.2; Sample Solvent: MEOH] to afford rel-(2R,4aS,10bR)-8-(difhioromethoxy)-2- methyl-l,3,4,4a,5,10b-hexahydro-2H-chromeno[4,3-b]pyridine isomer 1 (A57 isomer 1) (170 mg, 13%) as a pink oil with retention time at 6.7 min.; rel-(2R,4aS,10bR)-8- (difluoromethoxy)-2-methyl- 1 ,3, 4, 4a, 5, 10b-hexahydro-2H-chromeno[4,3-b]pyridine isomer 2 (A57 isomer 2) (120 mg, 9%) as a white solid with retention time at 7.9 min.; rel- (2R,4aS , 1 ObR)- 8- (difluoromethoxy)-2-methyl- 1,3, 4, 4a, 5,1 Ob-hexahy dro-2H-chromeno [4,3- b]pyridine isomer 3 (A57 isomer 3) (90 mg, 7%) as a white solid with retention time at 10.5 min. ; rel-(2R,4aS, 10bR)-8-(difhioromethoxy)-2-methyl- 1 ,3 ,4, 4a, 5 , 1 Ob-hexahy dro-2H- chromeno[4,3-b]pyridine isomer 4 (A57 isomer 4) (210 mg, 15.6%) as a white solid with retention time at 15.2 min.

[1283] rel-(2R,4aS, 10bR)-8-(difluoromethoxy)-2-methyl- 1 ,3, 4, 4a, 5, 10b-hexahydro-2H- chromeno[4,3-b]pyridine isomer 1 (A57 isomer 1): MS ESI calculated for C14H17F2NO2 [M+H]⁺, 270.12; found, 270.15. 'H NMR (400 MHz, DMSO-d₆) 6 7.36 - 6.99 (m, 2H), 6.64 (dd, J= 8.4, 2.8 Hz, 1H), 6.55 (d, J= 2.8 Hz, 1H), 4.49 - 4.43 (m, 1H), 3.97 - 3.91 (m, 1H), 3.66 (d, J = 3.2 Hz, 1H), 2.76 - 2.69 (m, 1H), 1.99 - 1.94 (m, 2H), 1.83 - 1.71 (m, 2H), 1.40 - 1.32 (m, 1H), 0.98 (d, 7 = 6.4 Hz, 3H).

[1284] rel-(2R,4aS,10bR)-8-(difluoromethoxy)-2-methyl-l,3,4,4a,5,10b-hexahydro-2H- chromeno[4,3-b]pyridine isomer 2 (A57 isomer 2): MS ESI calculated for C14H17F2NO2 [M+l]⁺, 270.12; found, 270.15. 'H NMR (400 MHz, DMSO-7₆) 87.46 (dd, J = 8.8, 1 .2 Hz, 1H), 7.17 (t, J = 74.4 Hz, 1H), 6.66 (dd, J = 8.4, 2.4 Hz, 1H), 6.53 (d, J = 2.4 Hz, 1H), 4.34 (d, 7 = 4.4 Hz, 1H), 4.15 (dd, 7= 10.8, 3.6 Hz, 1H), 3.89 - 3.82 (m, 1H), 3.43 - 3.40 (m, 1H), 2.79 - 2.69 (m, 1H), 2.17 (s, 1H), 1.78 - 1.65 (m, 2H), 1.58 - 1.45 (m, 1H), 1.09 (d, J= 6.4 Hz, 3H).

[1285] rel-(2R,4aS,10bR)-8-(difluoromethoxy)-2-methyl-l,3,4,4a,5,10b-hexahydro-2H- chromeno[4,3-b]pyridine isomer 3 (A57 isomer 3): MS ESI calculated for C14H17F2NO2 [M+H]⁺, 270.12; found, 270.15. ^XH NMR (400 MHz, DMSO-7₆) 8 7.47 (dd, J = 8.4, 1.2 Hz, 1H), 7.17 (t, J = 74.4 Hz, 1H), 6.66 (dd, J = 8.4, 2.8 Hz, 1H), 6.53 (d, J= 2.4 Hz, 1H), 4.15 (dd, 7= 10.4, 3.6 Hz, 1H), 3.85 (t, 7= 12.0 Hz, 1H), 3.43 - 3.32 (m, 2H), 2.74 (s, 1H), 2.17 (s, 1H), 1.76 - 1.68 (m, 2H), 1.58 - 1.45 (m, 1H), 1.09 (d, 7= 6.4 Hz, 3H). [1286] rel-(2R,4aS,10bR)-8-(difluoromethoxy)-2-methyl-l,3,4,4a,5,10b-hexahydro-2H- chromeno[4,3-b]pyridine isomer 4 (A57 isomer 4): MS ESI calculated for Ci4Hi7F₂NO₂ [M+H]⁺, 270.12; found, 270.15. 'H NMR (400 MHz, DMSO-A) 8 7.36 - 6.99 (m, 2H), 6.64 (dd, J= 8.4, 2.8 Hz, 1H), 6.55 (d, J= 2.4 Hz, 1H), 4.49 - 4.43 (m, 1H), 3.98 - 3.92 (m, 1H), 3.67 - 3.64 (m, 1H), 2.76 - 2.68 (m, 1H), 2.05 - 1.68 (m, 4H), 1.40 - 1.34 (m, 1H), 0.98 (d, J = 6.0 Hz, 3H).

Intermediate A58: 1:1 mixture of (4aR,9bR)-7-methoxy-l,2,3,4,4a,9b- hexahydrobenzofuro[3,2-b]pyridine and (4aS,9bS)-7-methoxy- 1 , 2, 3, 4, 4a, 9b- hexahydrobenzofuro[3,2-b]pyridine

A58

Step-1:

[1287] To a stirred solution of (2-fluoro-4-methoxyphenyl)boronic acid (10 g, 58.84 mmol) and 2-bromo-3-(methoxymethoxy)pyridine (12.83 g, 58.84 mmol) in 1,4-dioxane (200 mL) were added K₂CO₃ (24.40 g, 176.52 mmol) and Pd(dppf)Cl₂-CH₂C12 (4.81 g, 5.88 mmol) at room temperature under nitrogen atmosphere. The resulting mixture was stirred at 100 °C overnight. The resulting mixture was filtered, the filter cake was washed with ethyl acetate. The filtrate was concentrated under reduced pressure. The residue was dissolved in ethyl acetate and washed with brine, dried over anhydrous Na₂SC>4. After filtration, the filtrate was concentrated under reduced pressure. The resulting residue was purified by normal phase flash column chromatography with a 330 g silica gel column eluted with 0- 40% ethyl acetate in petroleum ether to afford 2-(2-fhioro-4-methoxyphenyl)-3- (methoxymethoxy)pyridine (13.1 g, 84% yield) as a brown oil. MS ESI calculated for Ci4H₁₄FNO₃ [M+H]⁺, 264.10; found, 264.30.

[1288] To a stirred solution 2-(2-fluoro-4-methoxyphenyl)-3-(methoxymethoxy)pyridine (13.1 g, 49.75 mmol) in DCM (90 mL) was added trifluoroacetic acid (56.74 g, 497.59 mmol) dropwise at 0 °C. The resulting mixture was stirred at room temperature overnight. The resulting mixture was concentrated under vacuum to afford 2-(2- fluoro-4-methoxyphenyl)pyridin-3-ol (23.3 g, crude) as a brown oil. The crude product was used in the next step directly without further purification. MS ESI calculated for C12H10FNO2 [M+H]⁺, 220.07; found, 220.00.

Step-3:

[1289] To a stirred solution of 2-(2-fluoro-4-methoxyphenyl)pyridin-3-ol (23.3 g, 106.28 mmol) was added K2CO3 (44.07 g, 318.86 mmol) at room temperature under nitrogen atmosphere. The resulting mixture was stirred at 120 °C overnight. The reaction was quenched with water at room temperature. The resulting mixture was extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SC>4. After filtration, the filtrate was concentrated under reduced pressure. The resulting residue was purified by normal phase flash column chromatography with a 330 g silica gel column eluted with 0^10% ethyl acetate in petroleum ether to afford 7-methoxybenzofuro[3,2-b]pyridine (9 g, 42% yield) as a light yellow solid. MS ESI calculated for C12H9NO2 [M+H]⁺, 200.06; found, 199.95.

Step-4:

[1290] To a stirred solution of 7-methoxybenzofuro[3,2-b]pyridine (2 g, 10.04 mmol) in toluene (20 mL) was added diphenylamine (6.80 g, 40.16 mmol), 4,4,5,5-tetramethyl-l,3,2- dioxaborolane (6.42 g, 50.20 mmol) and tris(pentafluorophenyl)borane (0.51 g, 1.00 mmol) at room temperature. The resulting mixture was stirred at 110 °C overnight. The reaction mixture was quenched by the addition of water and basified with NaHCCh (sat.) to pH ~8, then extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under vacuum. The resulting residue was purified by normal phase flash column chromatography eluted with 0- 24% methanol in dichloromethane to afford a 1:1 mixture of (4aR,9bR)-7-methoxy- l,2,3,4,4a,9b-hexahydrobenzofuro[3,2-b]pyridine and (4aS,9bS)-7-methoxy-l,2,3,4,4a,9b- hexahydrobenzofuro[3,2-b]pyridine (A58) (1.12 g, 54% yield) as a yellow solid. MS ESI calculated for C12H15NO2 [M+H]⁺, 206.11; found, 206.05. ¹H NMR (300 MHz, DMSO-sfe) 5 7.26 - 6.98 (m, 1H), 6.43 - 6.40 (m, 2H), 4.42 - 4.37 (m, 1H), 4.10 (d, J = 5.8 Hz, 1H), 3.71 (s, 3H), 2.72 - 2.43 (m, 2H), 2.08 - 1.76 (m, 2H), 1.56 - 1.26 (m, 2H).

Intermediate A58 isomer 1: rel-(4aR,9bR)-7-methoxy-l,2,3,4,4a,9b- hexahydrobenzofuro[3,2-b]pyridine isomer 1

Isomer

Intermediate A58 isomer 2: rel-(4aR,9bR)-7-methoxy-l,2,3,4,4a,9b- hexahydrobenzofuro[3,2-b]pyridine isomer 2

[1291] 1:1 mixture of (4aR,9bR)-7-methoxy-l,2,3,4,4a,9b-hexahydrobenzofuro[3,2- b]pyridine and (4aS,9bS)-7-methoxy-l,2,3,4,4a,9b-hexahydrobenzofuro[3,2-b]pyridine (A58) (4.6 g, 22.411 mmol) was separated by prep-chiral SFC with the following conditions: [Column: CHIRALPAK IG, 7*25cm, 10 pm; Mobile Phase A: CO2, Mobile Phase B: MEOH (0.1% 7M NHs-MeOH); Flow rate: 250 mL/min; Gradient (B%): isocratic 25% B; Column Temperature(°C): 35; Back Pressure(bar): 100; Wave Length: 220 nm; RTl(min): 9.23;

RT2(min): 12.39; Sample Solvent: MEOH] to afford rel-(4aR,9bR)-7-methoxy-l,2,3,4,4a,9b- hexahydrobenzofuro[3,2-b]pyridine isomer 1 (A58 isomer 1) (1.45 g, 31% yield) as a yellow solid with retention time at 9.23 minute. MS ESI calculated for C12H15NO2 [M+H]⁺, 206.11; found, 206.05. 'H NMR (300 MHz, DMSO-d₆) 3 7.26 - 6.98 (m, 1H), 6.43 - 6.40 (m, 2H), 4.42 - 4.37 (m, 1H), 4.10 (d, J= 5.8 Hz, 1H), 3.71 (s, 3H), 2.72 - 2.43 (m, 2H), 2.08 - 1.76 (m, 2H), 1.56 - 1.26 (m, 2H). Absolute stereochemistry was not determined.

[1292] The chiral resolution also afford rel-(4aR,9bR)-7-methoxy-l,2,3,4,4a,9b- hexahydrobenzofuro[3,2-b]pyridine isomer 2 (A58 isomer 2) (1.8 g, 39% yield) as a yellow solid with retention time at 12.39 minute. MS ESI calculated for C12H15NO2 [M+H]⁺, 206.11; found, 206.05. 'H NMR (300 MHz, DMSO-d₆) 3 7.26 - 6.98 (m, 1H), 6.43 - 6.40 (m, 2H), 4.42 - 4.37 (m, 1H), 4.10 (d, J= 5.8 Hz, 1H), 3.71 (s, 3H), 2.72 - 2.43 (m, 2H), 2.08 - 1.76 (m, 2H), 1.56 - 1.26 (m, 2H). Absolute stereochemistry was not determined.

Intermediate A59: 1:1 mixture of rel-(3R,4aS,9bS)-7-(difluoromethoxy)-3-methyl- l,2,3,4,4a,9b-hexahydrobenzofuro[3,2-b]pyridine isomer 1 and rel-(3R,4aS,9bS)-7- (difhjoromethoxy)-3-methyl-l,2,3,4,4a,9b-hexahydrobenzofuro[3,2-b]pyridine isomer 2

[1293] To a mixture of (2,4-dimethoxyphenyl)boronic acid (10.05 g, 55.22 mmol), 2- chloro-3-fhioro-5-methylpyridine (8.84 g, 60.74 mmol), Pd(dppf)Ch-CH2C12 (2.25 g, 2.75 mmol) and K2CO3 (11.45 g, 82.84 mmol) in Dioxane (100 mL) was added Water (10 mL). The mixture was stirred at 100 °C for 1 h. The solvents were removed under vacuum and purified directly. The resulting residue was purified by normal phase flash chromatography using a 330 g silica gel column eluted with 0-40% ethyl acetate in petroleum ether within 20 min to afford 2-(2,4-dimethoxyphenyl)-3-fluoro-5-methylpyridine (11.10 g, 81%) as a yellow solid. MS ESI calculated for C14H14FNO2 [M+H]⁺, 248.10; found, 248.05.

Step-2:

[1294] To a stirred solution of 2-(2,4-dimethoxyphenyl)-3-fluoro-5-methylpyridine (11.10 g, 44.48 mmol) in DCM (110 mL) was added a solution of BBt3 (IM in DCM) (135 mL, 135.00 mmol) at 0 °C. The mixture was stirred at room temperature for 3 h. The reaction was quenched with water and basified to pH 7 with saturated NaHCCh (aq.). The mixture was extracted with DCM. The combined organic layers were washed with brine, dried over anhydrous Na2SC>4, filtered, and concentrated under vacuum. The residue was purified by silica gel column chromatography, eluted with PE / EtOAc (3: 1) to afford 4-(3-fluoro-5- methylpyridin-2-yl)benzene-l,3-diol (6.0 g, 61%) as a yellow solid. MS ESI calculated for C12H10FNO2 [M+H]⁺, 220.07; found, 220.00.

Step-3:

[1295] To a stirred solution of 4-(3-fluoro-5-methylpyridin-2-yl)benzene-l,3-diol (6.0 g, 27.37 mmol) in N-methyl-2-pyrrolidone (60 mL) was added t-BuOK (6.14 g, 54.74 mmol) at room temperature. The resulting solution was stirred at 150 °C for 3 h. The reaction was cooled to 0 °C and acidified with HC1 (aq., 2N) to pH -7. The mixture was extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under vacuum. The resulting residue was purified by Combi Flash with a 330 g C18 column, eluted with 5-80% acetonitrile in water (10 mM NH4HCO3) to afford 3-methylbenzofuro[3,2-b]pyridin-7-ol (3.8 g, 70%) as a yellow solid. MS ESI calculated for C12H9NO2 [M+H]⁺, 200.05; found, 200.06.

Step-4:

[1296] To a stirred solution of 3-methylbenzofuro[3,2-b]pyridin-7-ol (3.8 g, 19.07 mmol) and K2CO3 (15.82 g, 114.45 mmol) in DMF (50 mL) was added sodium 2-chloro-2,2- difluoroacetate (11.63 g, 76.30 mmol) at room temperature under nitrogen atmosphere. The resulting mixture was stirred at 100 °C for 5 h. The resulting mixture was filtered, the filter cake was washed with ethyl acetate. The filtrate was concentrated under reduced pressure. The residue was quenched with water and extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SC>4. After filtration, the filtrate was concentrated under reduced pressure. The resulting residue was purified by normal phase flash column chromatography with a 120 g silica gel column eluted with 0-30% ethyl acetate in petroleum ether to afford 7-(difhioromethoxy)-3-methylbenzofuro[3,2-b]pyridine (1.7 g, 28%) as a brown solid. MS ESI calculated for C13H9F2NO2 [M+H]⁺, 250.06; found, 250.00. Isomer 1 Isomer 2

A59

[1297] To a 40 mL of screw cap vial was placed a solution of 7-(difluoromethoxy)-3- methylbenzofuro[3,2-b]pyridine (500 mg, 2.00 mmol) and N-phenylaniline (2.03 g, 12.01 mmol) in toluene (8 mL). Then 4,4,5,5-tetramethyl-l,3,2-dioxaborolane (1.29 g, 10.15 mmol) and tris(pentafluorophenyl)borane (103 mg, 0.20 mmol) were added at room temperature. The resulting mixture was stirred at 110 °C for 4 h under nitrogen atmosphere. The reaction was cooled to room temperature and quenched with water. The mixture was quenched with NaHCCh (sat.) and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under vacuum. The resulting residue was purified by Combi Flash with a 40 g silica gel column eluted with 0-25% methanol in dichloromethane to afford a 1:1 mixture of rel-(3R,4aS,9bS)-7- (difluoromethoxy)-3-methyl-l,2,3,4,4a,9b-hexahydrobenzofuro[3,2-b]pyridine isomer 1 and rel-(3R,4aS,9bS)-7-(difluoromethoxy)-3-methyl-l,2,3,4,4a,9b-hexahydrobenzofuro[3,2- b]pyridine isomer 2 (350 mg, 23%) as a yellow oil. MS ESI calculated for C13H15F2NO2 [M+H]⁺, 256.11; found, 256.15. 'H NMR (400 MHz, DMSO) 8 7.45 - 6.92 (m, 2H), 6.76 - 6.57 (m, 2H), 4.45 - 4.40 (m, 1H), 3.99 (d, J = 4.8 Hz, 1H), 2.73 - 2.59 (m, 1H), 2.23 - 2.15 (m, 1H), 2.13 - 2.05 (m, 2H), 1.66 - 1.54 (m, 1H), 1.53 - 1.44 (m, 1H), 0.83 (d, J = 6.4 Hz, 3H). Stereochemistry was not determined.

Intermediate A59 isomer 1: rel-(3R,4aS,9bS)-7-(difluoromethoxy)-3-methyl-l,2,3,4,4a,9b- hexahydrobenzofuro[3,2-b]pyridine isomer 1 isomer 1 _and>

Intermediate A59 isomer 2: rel-(3R,4aS,9bS)-7-(difluoromethoxy)-3-methyl-l,2,3,4,4a,9b- hexahydrobenzofuro[3,2-b]pyridine isomer 2

Isomer 2

[1298] A 1:1 mixture of rel-(3R,4aS,9bS)-7-(difluoromethoxy)-3-methyl-l,2,3,4,4a,9b- hexahydrobenzofuro[3,2-b]pyridine isomer 1 and rel-(3R,4aS,9bS)-7-(difluoromethoxy)-3- methyl-l,2,3,4,4a,9b-hexahydrobenzofuro[3,2-b]pyridine isomer 2 (350 mg) was separated by prep-chiral HPLC with the following conditions: [Column: CHIRALPAK IG, 2*25 cm, 5 pm; Mobile Phase A: Hex(0.5% 2M NH₃-MeOH)-HPLC, Mobile Phase B: MeOH: DCM=1: 1— HPLC; Flow rate: 20 mL/min; Gradient (B%): 15% B to 15% B in 10.5 min; Wave Length: 220/254 nm; RTl(min): 5.894; RT2(min): 8.921; Sample Solvent: MeOH: DCM=1: 1— HPLC] to afford rel-(3R,4aS,9bS)-7-(difluoromethoxy)-3-methyl-l,2,3,4,4a,9b- hexahydrobenzofuro[3,2-b]pyridine isomer 1 (A59 isomer 1) (70 mg, 20%) as a white solid with retention time at 5.894 minute. MS ESI calculated for C13H15F2NO2 [M+H]⁺, 256.11; found, 256.10. 'H NMR (400 MHz, DMSO) 8 7.45 - 6.92 (m, 2H), 6.76 - 6.57 (m, 2H), 4.45 - 4.40 (m, 1H), 3.99 (d, J = 4.8 Hz, 1H), 2.73 - 2.59 (m, 1H), 2.23 - 2.15 (m, 1H), 2.13 - 2.05 (m, 2H), 1.66 - 1.54 (m, 1H), 1.53 - 1.44 (m, 1H), 0.83 (d, J = 6.4 Hz, 3H). Absolute stereochemistry was not determined.

[1299] The separation also afford rel-(3R,4aS,9bS)-7-(difluoromethoxy)-3-methyl- l,2,3,4,4a,9b-hexahydrobenzofuro[3,2-b]pyridine isomer 2 (A59 isomer 2) (80 mg, 23%) as a white solid with retention time at 8.921 min. MS ESI calculated for C13H15F2NO2 [M+H]⁺, 256.11; found, 256.15. 'H NMR (400 MHz, DMSO) 8 7.45 - 6.92 (m, 2H), 6.76 - 6.57 (m, 2H), 4.45 - 4.40 (m, 1H), 3.99 (d, J = 4.8 Hz, 1H), 2.73 - 2.59 (m, 1H), 2.23 - 2.15 (m, 1H), 2.13 - 2.05 (m, 2H), 1.66 - 1.54 (m, 1H), 1.53 - 1.44 (m, 1H), 0.83 (d, J = 6.4 Hz, 3H). Absolute stereochemistry was not determined.

Intermediate A60: 1 : 1 :3:3 mixture of rel-(4R,4aR,9bR)-7-chloro-4-methyl-l,2,3,4,4a,9b- hexahydrobenzofuro[3,2-b]pyridine isomer 1 and rel-(4R,4aR,9bR)-7-chloro-4-methyl- l,2,3,4,4a,9b-hexahydrobenzofuro[3,2-b]pyridine isomer 2 and rel-(4R,4aR,9bR)-7-chloro-4- methyl-l,2,3,4,4a,9b-hexahydrobenzofuro[3,2-b]pyridine isomer 3 and rel-(4R,4aR,9bR)-7- chloro-4-methyl- 1 ,2,3,4,4a,9b-hexahydrobenzofuro[3,2-b]pyridine isomer 4 isomer 1 isomer 2 isomer 3 isomer 4

A60

Step-1:

[1300] To a stirred mixture of (4-chloro-2-hydroxyphenyl)boronic acid (6.60 g, 38.29 mmol) in 1,4-dioxane (120 mL) and H2O (12 mL) were added 2-chloro-3-fluoro-4- methylpyridine (5.57 g, 38.29 mmol), K2CO3 (15.88 g, 114.87 mmol) and Pd(dppf)Ch (2.80 g, 3.83 mmol) at room temperature under nitrogen atmosphere. The resulting mixture was stirred at 90 °C for 4 h. The resulting mixture was quenched with water and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous Na2SC>4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-30% ethyl acetate in petroleum ether to afford 5-chloro-2-(3-fluoro-4-methylpyridin-2-yl)phenol (4.80 g, 52%) as a green solid. MS ESI calculated for C12H9CIFNO [M+H]⁺, 238.04; found, 238.05.

[1301] The mixture of 5-chloro-2-(3-fluoro-4-methylpyridin-2-yl)phenol (4.80 g, 20.20 mmol) and K2CO3 (8.37 g, 60.59 mmol) in DMF (50 mL) was stirred at 120 °C for 2 h under nitrogen atmosphere. The reaction mixture was allowed to cool down to room temperature. The mixture was quenched with water and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous Na2SC>4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-25% ethyl acetate in petroleum ether to afford 7- chloro-4-methylbenzofuro[3,2-b]pyridine (3.30 g, 75%) as a white solid. MS ESI calculated for CI₂H₈C1NO [M+H]⁺, 218.03; found, 217.95.

Step-3: isomer 1 isomer 2 isomer 3 isomer 4

A60

[1302] To a stirred solution of 7-chloro-4-methylbenzofuro[3,2-b]pyridine (3.50 g, 16.08 mmol) in toluene (50 mL) were added Ph2NH (10.89 g, 64.32 mmol), HBpin (10.29 g, 80.41 mmol) and B(CeFs)3 (0.82 g, 1.61 mmol) at room temperature under nitrogen atmosphere. The resulting mixture was stirred at 110 °C for 16 h. The mixture was allowed to cool down to room temperature and quenched with water. The mixture was extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous Na2SC>4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by reverse phase column chromatography with 5% to 60% MeCN in Water (0.1% TFA) to afford a 1: 1:2:2 mixture of rel-(4R,4aR,9bR)-7-chloro-4-methyl-l,2,3,4,4a,9b- hexahydrobenzofuro[3,2-b]pyridine isomer 1 and rel-(4R,4aR,9bR)-7-chloro-4-methyl- l,2,3,4,4a,9b-hexahydrobenzofuro[3,2-b]pyridine isomer 2 and rel-(4R,4aR,9bR)-7-chloro-4- methyl-l,2,3,4,4a,9b-hexahydrobenzofuro[3,2-b]pyridine isomer 3 and rel-(4R,4aR,9bR)-7- chloro-4-methyl-l,2,3,4,4a,9b-hexahydrobenzofuro[3,2-b]pyridine isomer 4 (A60) (3.07 g, 85%) as a white solid. MS ESI calculated for C12H14CINO [M+H]⁺, 224.08; found, 224.00.

Intermediate A60 isomer 1: rel-(4R,4aR,9bR)-7-chloro-4-methyl-l,2,3,4,4a,9b- hexahydrobenzofuro[3,2-b]pyridine isomer 1 and,

Intermediate A60 isomer 2: rel-(4R,4aR,9bR)-7-chloro-4-methyl-l,2,3,4,4a,9b- hexahydrobenzofuro[3,2-b]pyridine isomer 2 and,

Intermediate A60 isomer 3: rel-(4R,4aR,9bR)-7-chloro-4-methyl-l,2,3,4,4a,9b- hexahydrobenzofuro[3,2-b]pyridine isomer 3 and,

Intermediate A60 isomer 4: rel-(4R,4aR,9bR)-7-chloro-4-methyl-l,2,3,4,4a,9b- hexahydrobenzofuro[3,2-b]pyridine isomer 4

[1303] The 1:1:2:2 mixture of rel-(4R,4aR,9bR)-7-chloro-4-methyl-l,2,3,4,4a,9b- hexahydrobenzofuro[3,2-b]pyridine isomer 1 and rel-(4R,4aR,9bR)-7-chloro-4-methyl- l,2,3,4,4a,9b-hexahydrobenzofuro[3,2-b]pyridine isomer 2 and rel-(4R,4aR,9bR)-7-chloro-4- methyl-l,2,3,4,4a,9b-hexahydrobenzofuro[3,2-b]pyridine isomer 3 and rel-(4R,4aR,9bR)-7- chloro-4-methyl-l,2,3,4,4a,9b-hexahydrobenzofuro[3,2-b]pyridine isomer 4 (A60) (3.0 g) was separated by Prep-Achiral-SFC with the following conditions: [Column: DAICEL DCpak P4VP 3*25 cm, 5 pm; Mobile Phase A: CO2, Mobile Phase B: MeOH(20mM NH3); Flow rate: 60 mL/min; Gradient: isocratic 22% B; Column Temperature(°C): 35; Back Pressure(bar): 100; Wave Length: 254 nm; RTl(min): 4.24; RT2(min): 5.04; Sample Solvent: MeOH— HPLC; Injection Volume: 1.5 mL; Number Of Runs: 18.0] to afford fraction A (380 mg) with retention time at 4.24 minute and fraction B (660 mg) with retention time at 5.04 minute.

[1304] The fraction A was separated by Prep-Chiral-HPLC with the following conditions: [Column: CHIRALPAK AS-H, 2*25 cm, 5 pm; Mobile Phase A: Hex(0.5% 2M NH₃- MeOH), Mobile Phase B: MeOH: EtOH=l: 1— HPLC; Flow rate: 20 mL/min; Gradient: 1% B to 1% B in 8 min; Wave Length: 220/254 nm; RTl(min): 5.82; RT2(min): 6.07; Sample Solvent: EtOH: DCM=1: 1— HPLC; Injection Volume: 0.17 mL; Number Of Runs: 28] to afford rel-(4R,4aR,9bR)-7-chloro-4-methyl-l,2,3,4,4a,9b-hexahydrobenzofuro[3,2-b]pyridine isomer 1 (A60 isomer 1) (100 mg) as a yellow solid with shorter retention time and rel- (4R,4aR,9bR)-7-chloro-4-methyl-l,2,3,4,4a,9b-hexahydrobenzofuro[3,2-b]pyridine isomer 2 (A60 isomer 2) (120 mg) as a yellow solid with longer retention time.

[1305] rel-(4R,4aR,9bR)-7-chloro-4-methyl- 1 ,2,3,4,4a,9b-hexahydrobenzofuro[3,2- b]pyridine isomer 1 (A60 isomer 1): MS ESI calculated for C12H14CINO [M+H]⁺, 224.08; found, 224.10. ^XH NMR (400 MHz, DMSO-J₆) 3 7.34 (d, J= 7.9 Hz, 1H), 7.03 (d, J= 1.9 Hz, 1H), 6.97 (dd, J = 7.9, 1.9 Hz, 1H), 4.40 (t, J = 4.3 Hz, 1H), 4.30 (d, J = 5.1 Hz, 1H), 2.86 - 2.77 (m, 1H), 2.69 - 2.61 (m, 1H), 2.10 - 1.98 (m, 1H), 1.58 - 1.50 (m, 1H), 1.32 - 1.22 (m, 1H), 1.14 (d, J = 6.9 Hz, 3H). Absolute stereochemistry was not determined.

[1306] rel-(4R,4aR,9bR)-7-chloro-4-methyl-l,2,3,4,4a,9b-hexahydrobenzofuro[3,2- b]pyridine isomer 2 (A60 isomer 2): MS ESI calculated for C12H14CINO [M+H]⁺, 224.08; found, 224.10. 'H NMR (400 MHz, DMSO-sfc) 8 7.34 (d, J= 7.9 Hz, 1H), 7.03 (d, J= 1.9 Hz, 1H), 6.97 (dd, J = 7.9, 1.9 Hz, 1H), 4.40 (t, J = 4.3 Hz, 1H), 4.30 (d, J = 5.1 Hz, 1H), 2.86 - 2.77 (m, 1H), 2.69 - 2.61 (m, 1H), 2.10 - 1.98 (m, 1H), 1.58 - 1.50 (m, 1H), 1.32 - 1.22 (m, 1H), 1.14 (d, J = 6.9 Hz, 3H). Absolute stereochemistry was not determined.

[1307] The fraction B (450 mg) was separated by Prep-Chiral-HPLC with the following conditions: [Column: CHIRALPAK IG, 2*25 cm, 5 pm; Mobile Phase A: Hex(0.5% 2M NHj-MeOH), Mobile Phase B: EtOH: DCM=1: 1— HPLC; Flow rate: 20 mL/min; Gradient: 10% B to 10% B in 12 min; Wave Length: 220/254 nm; RTl(min): 8.75; RT2(min): 10.33; Sample Solvent: EtOH: DCM=1 : 1— HPLC; Injection Volume: 0.2 mL; Number Of Runs: 26] to afford rel-(4R,4aR,9bR)-7-chloro-4-methyl- l,2,3,4,4a,9b-hexahydrobenzofuro[3,2- b]pyridine isomer 3 (A60 isomer 3) (140 mg) as a yellow solid with shorter retention time and rel-(4R,4aR,9bR)-7-chloro-4-methyl-l,2,3,4,4a,9b-hexahydrobenzofuro[3,2-b]pyridine isomer 4 (A60 isomer 4) (160 mg) as a yellow solid with longer retention time.

[1308] rel-(4R,4aR,9bR)-7-chloro-4-methyl-l,2,3,4,4a,9b-hexahydrobenzofuro[3,2- b]pyridine isomer 3 (A60 isomer 3): MS ESI calculated for C12H14CINO [M+H]⁺, 224.08; found, 224.10. 'H NMR (400 MHz, DMSO-sfc) 6 7.31 (d, J= 8.5 Hz, 1H), 7.00 - 6.93 (m, 2H), 4.60 (d, J = 7.2 Hz, 1H), 4.28 (t, J = 7.4 Hz, 1H), 2.87 - 2.79 (m, 1H), 2.71 - 2.63 (m, 1H), 1.87 - 1.75 (m, 1H), 1.67 - 1.57 (m, 1H), 1.28 - 1.14 (m, 1H), 1.08 (d, J = 6.8 Hz, 3H). Absolute stereochemistry was not determined. [1309] rel-(4R,4aR,9bR)-7-chloro-4-methyl-l,2,3,4,4a,9b-hexahydrobenzofuro[3,2- b]pyridine isomer 4 (A60 isomer 4): MS ESI calculated for C12H14CINO [M+H]⁺, 224.08; found, 224.10. 'H NMR (400 MHz, DMSO-A) 8 7.31 (d, J = 8.5 Hz, 1H), 7.00 - 6.93 (m, 2H), 4.60 (d, J = 7.2 Hz, 1H), 4.28 (t, J = 7.4 Hz, 1H), 2.87 - 2.79 (m, 1H), 2.71 - 2.63 (m, 1H), 1.87 - 1.75 (m, 1H), 1.67 - 1.57 (m, 1H), 1.28 - 1.14 (m, 1H), 1.08 (d, J = 6.8 Hz, 3H), Absolute stereochemistry was not determined.

Intermediate A61 : (2R,4aR, 1 ObS)-8-chloro-2-methyl-2,3 ,4a, 5 ,6, 1 Ob-hexahydro- 1 H-

[1 ,4]oxazino[2,3-h]isoquinoline

Step-1:

[1310] To a stirred solution of 3-chloro-6,7-dihydroisoquinolin-8(5H)-one (5.0 g, 27.5 mmol) in methanol (100 mL) was added NaBFU (1.56 g, 41.3 mmol) at 0 °C. The resulting mixture was stirred at room temperature for 2 h. The reaction was quenched with water, and the methanol was removed under reduced pressure. The remained mixture was extracted with ethyl acetate. The organic layers were dried over anhydrous Na2SO4. After filtration, the filtrate was concentrated under reduced pressure. This resulted in a 1 : 1 mixture of (R)-3- chloro-5,6,7,8-tetrahydroisoquinolin-8-ol and (S)-3-chloro-5,6,7,8-tetrahydroisoquinolin-8-ol (5.7 g, crude) as a yellow oil. MS ESI calculated for C9H10CINO [M+H]⁺, 184.05; found, 184.15.

Step-2:

[1311] A solution of a 1:1 mixture of (R)-3-chloro-5,6,7,8-tetrahydroisoquinolin-8-ol and (S)-3-chloro-5,6,7,8-tetrahydroisoquinolin-8-ol (27.0 g, 147 mmol) in PPA (300 mL) was stirred at 120 °C for 2 h under nitrogen atmosphere. The mixture was allowed to cool down to room temperature and quenched with water. The mixture was basified to PH 7~8 with Na2CC>3 (sat.) and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous Na2SO4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-10% ethyl acetate in petroleum ether to afford 3-chloro-5,6-dihydroisoquinoline (5.8 g, 23%) as a colorless Equid. MS ESI calculated for CgHsCIN [M+H]⁺, 166.03; found, 166.15.

Step-3:

[1312] To a stirred solution of tert-butyl carbamate (10.3 g, 87.9 mmol) in propan-l-ol (220 mL) was added a solution of a solution of NaOH (3.06 g, 76.6 mmol) in H2O (190 mL) at room temperature and then stirred for 15 minutes. l,3-dichloro-5,5-dimethylimidazolidine- 2, 4-dione (8.39 g, 42.5 mmol) was added to the mixture, the mixture was stirred at room temperature for 30 minutes. Then (DHQ)2PHAL (supplier: Shanghai Accela ChemBio Co., Ltd. CAS# 140924-50-1) (2.21 g, 2.83 mmol), 3-chloro-5,6-dihydroisoquinoline (4.70 g, 28.3 mmol) and Potassium osmate(VI) dihydrate (1.05 g, 2.83 mmol) were added to the mixture. The mixture was stirred at room temperature for 16 h. The reaction mixture was extracted with ethyl acetate. The organic layers were dried over anhydrous Na2SC>4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by Prep-HPLC with the following conditions [Column: XBridge Prep OBD C18 Column, 30*150 mm, 5pm; Mobile Phase A: Water(10 mmol/L NH4HCO3), Mobile Phase B: ACN; Flow rate: 60 mL/min; Gradient: 27% B to 47% B in 14 min; Wave Length: 254/220 nm; RTl(min): 9] to afford a 1:4 mixture of tert-butyl ((7R,8S)-3-chloro-7-hydroxy-5,6,7,8-tetrahydroisoquinolin- 8-yl)carbamate and tert-butyl ((7S,8R)-3-chloro-7-hydroxy-5,6,7,8-tetrahydroisoquinolin-8- yl)carbamate (3.7 g, 43%) as a grey solid. MS ESI calculated for C14H19CIN2O3 [M+H]⁺, 299.11; found, 299.05.

Step-4:

[1313] To a solution of a 1:4 mixture of tert-butyl ((7R,8S)-3-chloro-7-hydroxy-5,6,7,8- tetrahydroisoquinolin-8-yl)carbamate and tert-butyl ((7S, 8R)-3-chloro-7-hydroxy-5, 6,7,8- tetrahydroisoquinolin-8-yl)carbamate (2.70 g, 9.03 mmol) in DCM (30 mL) were sequentially added (Bu4N)HSC>4 (613 mg, 1.80 mmol), NaOH (2.53 g, 63.2 mmol) and (4S)- 4-methyl- 1,3, 2-k-6-dioxathiolane-2, 2-dione (supplier: Suzhou spark Biotechnology Co., Ltd. CAS# 174953-30-1 ) (1.62 g, 11 .7 mmol). The resulting mixture was stirred at room temperature for 2 h. The mixture was concentrated under reduced pressure. The residue was dissolved in water and neutralized with HC1 (aq.) to PH~7. The resulting mixture was extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous NazSCh. After filtration, the filtrate was concentrated under reduced pressure.

[1314] The residue was dissolved in 2-methoxy-2-methylpropane (21 mL) and H2O (0.07 mL), than TsOH (17 mg, 0.10 mmol) and 1,4-dioxane (0.6 mL) were added. The resulting mixture was stirred at 80 °C for 2 h. The resulting mixture was concentrated under reduced pressure. The residue was dissolved in methanol (30 mL), this was followed by the addition of EtaN (2.74 g, 27.1 mmol) and BoczO (2.96 g, 13.5 mmol). The resulting mixture was stirred at room temperature for 1 h. The resulting mixture was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-60% ethyl acetate in petroleum ether to afford a 1:4 mixture of tert-butyl ((7R,8S)-3-chloro-7-((S)- 2-hydroxypropoxy)-5,6,7,8-tetrahydroisoquinolin-8-yl)carbamate and tert-butyl ((7S,8R)-3- chloro-7-((S)-2-hydroxypropoxy)-5,6,7,8-tetrahydroisoquinolin-8-yl)carbamate (2.85 g, 88%) as a white solid. MS ESI calculated for C17H25CIN2O4 [M+H]⁺, 357.15; found, 357.05.

Step-5:

[1315] To a stirred solution of a 1:4 mixture of tert-butyl ((7R,8S)-3-chloro-7-((S)-2- hydroxypropoxy)-5,6,7,8-tetrahydroisoquinolin-8-yl)carbamate and tert-butyl ((7S,8R)-3- chloro-7-((S)-2-hydroxypropoxy)-5,6,7,8-tetrahydroisoquinolin-8-yl)carbamate (3.75 g, 10.5 mmol) and TEA (4.25 g, 42.0 mmol) in DCM (40 mL) was added MS2O (3.11 g, 17.8 mmol) in portions at room temperature. The resulting mixture was stirred at room temperature for 1 h. The resulting mixture was quenched with water and extracted with DCM. The organic layers were dried over anhydrous Na2SO4. After filtration, the filtrate was concentrated under reduced pressure.

[1316] The residue was dissolved in DCM (30 mL), and then TFA (10 mL) was added. The resulting mixture was stirred at room temperature for 1 h. The mixture was concentrated under vacuum. The residue was dissolved in MeCN (120 mL), and then 1, 2, 2,6,6- pentamethylpiperidine (21.1 g, 136 mmol) was added. The resulting solution was stirred at 60 °C for 16 h. The reaction mixture was concentrated under reduced pressure. The residue was purified by Prep-HPLC with the following conditions [Column: XSelect CSH Prep Cl 8 OBD Column, 30*150 mm, 5pm; Mobile Phase A: Water (0.05% TFA), Mobile Phase B: ACN; Flow rate: 60 mL/min; Gradient (B%): 5% B to 40% B in 12min; Wave Length: 254/220 nm; RTl(min): 8.1; RT2(min): 9.1] to afford (2R,4aR,10bS)-8-chloro-2-methyl- 2,3,4a,5,6,10b-hexahydro-lH-[l,4]oxazino[2,3-h]isoquinoline (A61) (290 mg, 10%) as a white solid as the first eluting peak by Prep-HPLC. MS ESI calculated for C12H15CIN2O [M+H]⁺, 239.09; found, 239.15. 'H NMR (400 MHz, DMSO-ck) 5 8.29 (s, 1H), 7.27 (s, 1H), 3.94 - 3.89 (m, 1H), 3.87 - 3.81 (m, 1H), 3.47 - 3.40 (m, 1H), 3.20 (t, J= 10.4 Hz, 1H), 2.97 - 2.87 (m, 2H), 2.81 - 2.71 (m, 1H), 2.63 - 2.52 (m, 1H), 1.59 - 1.50 (m, 1H), 0.86 (d, J = 6.4 Hz, 3H). Absolute stereochemistry was determined by NOESY.

Intermediate A62: (2R,4aR,10bS)-8-bromo-2-methyl-2,3,4a,5,6,l Ob-hexahydro-lH-

[ 1 ,4] oxazino[2,3-h] quinoline

A62

Step-1:

[1317] To a stirred solution of 3-bromo-6,7-dihydroquinolin-8(5H)-one (4.30 g, 19.11 mmol) in methanol (40 mL) was added NaBH4 (863 mg, 22.93 mmol) in portions at 0 °C. The resulting mixture was stirred at room temperature for 1 h. The reaction was quenched with water. The resulting mixture was extracted with ethyl acetate. The combined organic layers were dried over anhydrous Na2SO4. After filtration, the filtrate was concentrated under reduced pressure to afford a 1:1 mixture of (R)-3-bromo-5,6,7,8-tetrahydroquinolin-8-ol and (S)-3-bromo-5,6,7,8-tetrahydroquinolin-8-ol (4.34 g, crude) as a colorless oil. MS ESI calculated for C₉HioBrNO [M+H]⁺, 227.99, 229.99; found, 228.00, 229.95.

Step-2:

[1318] A solution of a 1:1 mixture of (R)-3-bromo-5,6,7,8-tetrahydroquinolin-8-ol and (S)- 3-bromo-5,6,7,8-tetrahydroquinolin-8-ol (4.34 g, 19.11 mmol) in PPA (30 mL) was stirred at 120 °C for 1 h. The mixture was allowed to cool down to room temperature and quenched with water. The mixture was basified with saturated Na2CO3 (aq.) to PH 7~8 and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous NazSC . After filtration, the filtrate was concentrated under reduced pressure to afford 3-bromo-5,6-dihydroquinoline (3.70 g, crude) as a colorless oil. MS ESI calculated for C₉HsBrN [M+H]⁺, 209.98, 211.98; found, 209.95, 211.95.

Step-3:

[1319] To a stirred solution of 3-bromo-5,6-dihydroquinoline (3.70 g, 17.61 mmol) in DMSO (40 mL) and H2O (8 mL) was added NBS (3.76 mg, 21.13 mmol) at 0 °C. The resulting mixture was stirred at 0 °C for 1 h. The mixture was quenched with water and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under reduced pressure. The residue was dissolved in MeOH (6 mL), then ammonium hydroxide (28% in water) (60 mL) was added. The mixture was stirred at room temperature for 20 h. The resulting mixture was concentrated under reduced pressure to afford a 1:1 mixture of (7S,8S)-8-amino-3-bromo- 5,6,7,8-tetrahydroquinolin-7-ol and (7R,8R)-8-amino-3-bromo-5,6,7,8-tetrahydroquinolin-7- ol (5.47 g, crude) as a brown solid. MS ESI calculated for CgHnBr^O [M+H]⁺, 243.01, 245.01; found, 243.00, 245.00.

Step-4:

[1320] To a stirred solution of a 1:1 mixture of (7S,8S)-8-amino-3-bromo-5, 6,7,8- tetrahydroquinolin-7-ol and (7R,8R)-8-amino-3-bromo-5,6,7,8-tetrahydroquinolin-7-ol (4.20 g, 17.28 mmol) in DCM (50 mL) were added TEA (5.24 g, 51.83 mmol) and benzoyl chloride (2.67 g, 19.00 mmol) at 0 °C. The resulting mixture was stirred at room temperature for 2 h. The mixture was quenched with water and extracted with DCM. The combined organic layers were washed with brine, dried over anhydrous NazSCh, filtered, and concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-10% methanol in dichloromethane to afford a 1:1 mixture of N-((7S,8S)-3-bromo-7-hydroxy-5,6,7,8-tetrahydroquinolin-8-yl)benzamide and N-((7R,8R)- 3-bromo-7-hydroxy-5,6,7,8-tetrahydroquinolin-8-yl)benzamide (5.90 g, 98%) as a brown solid. MS ESI calculated for CieHisBrNzOz [M+H]⁺, 347.03, 349.03; found, 347.05, 349.00.

Step-5:

[1321] To a stirred solution of a 1 : 1 mixture of N-((7S, 8S)-3-bromo-7-hydroxy-5, 6,7,8- tetrahydroquinolin-8-yl)benzamide and N-((7R, 8R)-3-bromo-7-hydroxy-5, 6,7,8- tctrahydroquinolin-8-yl)bcnzamidc (5.70 g, 16.43 mmol) in DCM (60 mL) was added SOCh (3.88 g, 32.85 mmol) dropwise at 0 °C under nitrogen atmosphere. The resulting mixture was stirred at room temperature for 2 h. The reaction was quenched by the addition of water at 0 °C. The resulting mixture was extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous NazSCU. After filtration, the filtrate was concentrated under reduced pressure to afford a 1:1 mixture of (3aR,9bS)-7-bromo-2-phenyl- 3a,4,5,9b-tetrahydrooxazolo[5,4-h]quinoline and (3aS,9bR)-7-bromo-2-phenyl-3a,4,5,9b- tetrahydrooxazolo[5,4-h]quinoline (5.50 g, crude) as a brown oil. MS ESI calculated for Ci₆Hi3BrN₂O [M+H]⁺, 329.02, 331.02; found, 328.95, 331.00.

Step-6:

[1322] To a mixture of a 1: 1 mixture of (3aR,9bS)-7-bromo-2-phenyl-3a,4,5,9b- tetrahydrooxazolo[5,4-h]quinoline and (3aS,9bR)-7-bromo-2-phenyl-3a,4,5,9b- tetrahydrooxazolo[5,4-h]quinoline (5.00 g, 15.19 mmol) in H2O (25 mL) and 1,4-dioxane (25 mL) was added HC1 (cone.) (25 mL). The resulting mixture was stirred at 80 °C for 16 h. After cooling drown, the reaction mixture was concentrated under reduced pressure. The residue was dissolved in MeOH (60 mL), and then TEA (7.59 g, 74.38 mmol) and BociO (8.11 g, 37.19 mmol) were added at 0 °C. The resulting mixture was stirred at room temperature for 2 h. The resulting mixture was concentrated under reduced pressure and purified by silica gel column chromatography, eluted with 0-50% ethyl acetate in petroleum ether to afford a 1:1 mixture of tert-butyl ((7R, 8S)-3-bromo-7-hydroxy-5, 6,7,8- tetrahydroquinolin-8-yl)carbamate and tert-butyl ((7S,8R)-3-bromo-7-hydroxy-5, 6,7,8- tetrahydroquinolin-8-yl)carbamate (1.00 g, 12%) as a yellow oil. MS ESI calculated for Ci4Hi₉BrN₂O3 [M+H]⁺, 343.06, 345.06; found, 343.05, 345.00.

[1323] To a stirred solution of a 1:1 mixture of tert-butyl ((7R,8S)-3-bromo-7-hydroxy- 5,6,7,8-tetrahydroquinolin-8-yl)carbamate and tert-butyl ((7S,8R)-3-bromo-7-hydroxy- 5,6,7,8-tetrahydroquinolin-8-yl)carbamate (940 mg, 2.74 mmol) in DCM (10 mL) were added (Bu4N)HSO4 (186 mg, 0.55 mmol), NaOH (767 mg, 19.17 mmol) and (4S)-4-methyl- 1,3, 2-X-6-dioxathiolane-2, 2-dione (supplier: Suzhou spark Biotechnology Co., Ltd. CAS# 174953-30-1) (492 mg, 3.56 mmol) at room temperature. The resulting mixture was stirred at room temperature for 4 h. The resulting mixture was concentrated under reduced pressure and quenched with water. The mixture was neutralized with HC1 (aq.) to PH~7. The mixture was concentrated under reduced pressure. The residue was dissolved in 2-methoxy-2- methylpropane (45 mL) and H2O (1.5 mL). then TsOH (283 mg, 1.64 mmol) and 1,4-dioxane (6 mL) were added. The resulting mixture was stirred at 80 °C for 16 h under nitrogen atmosphere. The resulting mixture was concentrated under reduced pressure. The residue was dissolved in MeOH (10 mL), and then TEA (300 mg, 8.84 mmol) and BOC2O (970 g, 4.42 mmol) were added. The resulting mixture was stirred at room temperature for 1.5 h. The resulting mixture was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-50% ethyl acetate in petroleum ether to afford a 1:1 mixture of tert-butyl ((7R,8S)-3-bromo-7-((S)-2-hydroxypropoxy)-5, 6,7,8- tetrahydroquinolin-8-yl)carbamate and tert-butyl ((7S,8R)-3-bromo-7-((S)-2- hydroxypropoxy)-5,6,7,8-tetrahydroquinolin-8-yl)carbamate (740 mg, 63%) as a yellow oil. MS ESI calculated for Ci7H25BrN₂O₄ [M+H]⁺, 401.10, 403.10; found, 401.05, 403.05.

Step-8:

[1324] To a stirred solution of a 1:1 mixture of tert-butyl ((7R,8S)-3-bromo-7-((S)-2- hydroxypropoxy)-5,6,7,8-tetrahydroquinolin-8-yl)carbamate and tert-butyl ((7S,8R)-3- bromo-7-((S)-2-hydroxypropoxy)-5,6,7,8-tetrahydroquinolin-8-yl)carbamate (500 mg, 1.25 mmol) and TEA (378 mg, 3.74 mmol) in DCM (5 mL) was added MsiO (369 mg, 2.12 mmol) in portions at room temperature. The resulting mixture was stirred at room temperature for 2 h. The reaction was quenched by water and extracted with CH2CI2. The combined organic layers were dried over anhydrous Na2SC>4. After filtration, the filtrate was concentrated under reduced pressure. The residue was dissolved in DCM (6 mL), and then TFA (2 mL) was added. The resulting mixture was stirred at room temperature for 1.5 h. The mixture was concentrated under reduced pressure. The residue was dissolved in MeCN (10 L), and then 1,2,2,6,6-pentamethylpiperidine (1.98 g, 12.72 mmol) was added. The resulting mixture was stirred at 60 °C for 16 h. The mixture was concentrated under reduced pressure. The residue was purified by Prep-HPLC with the following conditions [Column: XSelect CSH Prep C18 OBD Column, 19*250 mm, 5pm; Mobile Phase A: Water (10 mmol/L NH4HCO3), Mobile Phase B: ACN; Flow rate: 20 mL/min; Gradient: 20% B to 30% B in 10 min, 30% B to 30% B in 20 min; Wave Length: 254/220 nm; RTl(min): 11.43; RT2(min): 15.6] to afford (2R,4aR,10bS)-8-bromo-2-methyl-2,3,4a,5,6,10b-hexahydro-lH- [l,4]oxazino[2,3-h]quinoline (A62) (160 mg, 45%) as a white solid with the first peak on HPLC. MS ESI calculated for Ci₂Hi₅BrN₂O [M+H]⁺, 283.04, 285.04; found, 283.00, 285.00. 'H NMR (400 MHz, Chloroform-^ 5 8.47 (s, 1H), 7.60 (s, 1H), 4.10 - 4.01 (m, 2H), 3.63 - 3.56 (m, 1H), 3.45 - 3.38 (m, 1H), 3.20 - 3.09 (m, 1H), 2.95 - 2.86 (m, 1H), 2.85 - 2.74 (m, 1H), 2.70 - 2.57 (m, 1H), 1.81 - 1.73 (m, 1H), 0.94 (d, J= 6.4 Hz, 3H).

[1325] The separation also afford (2R,4aS,10bR)-8-bromo-2-methyl-2,3,4a,5,6,10b- hexahydro-lH-[l,4]oxazino[2,3-h]quinolone (134 mg, 37%) as a white solid with the second peak on HPLC. MS ESI calculated for Ci₂Hi₅BrN₂O [M+H]⁺, 283.04, 285.04; found, 283.00, 285.00. 'H NMR (400 MHz, Chloroform-7) 5 8.50 (s, 1H), 7.56 (s, 1H), 4.20 - 4.14 (m, 1H), 3.80 - 3.75 (m, 1H), 3.69 - 3.63 (m, 1H), 3.32 (t, J = 10.6 Hz, 1H), 3.17 - 3.04 (m, 1H), 2.67 - 2.58 (m, 1H), 2.57 - 2.47 (m, 1H), 2.22 - 2.13 (m, 1H), 1.90 - 1.79 (m, 1H), 0.92 (d, 7 = 6.4 Hz, 3H).

Intermediate A63: 1 :1 :3:3 mixture of rel-(3R,4aS,9bS)-7-(difluoromethoxy)-3-methoxy- l,2,3,4,4a,9b-hexahydrobenzofuro[3,2-b]pyridine isomer 1 and rel-(3R,4aS,9bS)-7- (difhjoromethoxy)-3-methoxy-l,2,3,4,4a,9b-hexahydrobenzofuro[3,2-b]pyridine isomer 2 and rel-(3R,4aR,9bR)-7-(difluoromethoxy)-3-methoxy-l,2,3,4,4a,9b- hexahydrobenzofuro[3,2-b]pyridine isomer 3 and rel-(3R,4aR,9bR)-7-(difluoromethoxy)-3- methoxy-l,2,3,4,4a,9b-hexahydrobenzofuro[3,2-b]pyridine isomer 4

Isomer 1 Isomer 2 Isomer 3 Isomer 4

A63

Step-1:

[1326] To a stirred solution of 6-chloro-5-fluoropyridin-3-ol (24.70 g, 167.42 mmol) and CS2CO3 (109.10 g, 334.84 mmol) in MeCN (250 mL) was added CH3I (21 mL, 337.32 mmol) dropwise at 0 °C. The resulting mixture was stirred at 25 °C for 2 h. The resulting mixture was filtered, the filter cake was washed with EtOAc. The filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with PE/ EtOAc (1:1) to afford 2-chloro-3-fluoro-5-methoxypyridine (24.00 g, 88%) as a yellow ofi. MS ESI calculated for C₆H₅C1FNO [M+H]⁺, 162.00; found, 162.10.

Step-2:

[1327] To a stirred solution of 2-chloro-3-fluoro-5-methoxypyridine (28.00 g, 173.31 mmol) and (4-chloro-2-hydroxyphenyl)boronic acid (35.85 g, 207.97 mmol) in 1,4-dioxane (280 mL) and H2O (28 mL) were added K2CO3 (71.86 g, 519.93 mmol) and Pd(dppf)Ch- CH2CI2 (14.15 g, 17.33 mmol) at room temperature under nitrogen atmosphere. The resulting mixture was stirred at 100 °C for 2 h. The resulting mixture was quenched with water and extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous NazSC . After filtration, the filtrate was concentrated under reduced pressure. The resulting residue was purified by flash column chromatography with 0-20% ethyl acetate in petroleum ether to afford 5-chloro-2-(3-fluoro-5-methoxypyridin-2-yl)phenol (31.50 g, 71%) as a light yellow solid. MS ESI calculated for C12H9CIFNO2 [M+H]⁺, 254.03; found, 254.00.

Step-3:

[1328] To a stirred solution of 5-chloro-2-(3-fluoro-5-methoxypyridin-2-yl)phenol (30.00 g, 118.26 mmol) in DMF (300 mL) was added K2CO3 (49.04 g, 354.80 mmol) at room temperature. The resulting mixture was stirred at 120 °C for 2 h under nitrogen atmosphere. The resulting mixture was quenched with water and extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SO4. After filtration, the filtrate was concentrated under reduced pressure. The resulting residue was purified by flash column chromatography with 0-20% ethyl acetate in petroleum ether to afford 7-chloro-3- methoxybenzofuro[3,2-b]pyridine (20.00 g, 72%) as a yellow solid. MS ESI calculated for C12H8CINO2 [M+H]⁺, 234.02; found, 234.15.

Step-4:

[1329] To a stirred solution of 7-chloro-3-methoxybenzofuro[3,2-b]pyridine (11.00 g, 47.07 mmol) and BPD (11.96 g, 47.07 mmol) in 1,4-dioxane (110 mL) were added AcOK (13.86 g, 141.23 mmol) and Pd(dppf)C12-CH2C12 (3.84 g, 4.70 mmol) at room temperature under nitrogen atmosphere. The resulting mixture was stirred at 80 °C for 16 h under nitrogen atmosphere. The resulting mixture was quenched with water and extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous NazSC After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with CH2CI2 / PE (1:10) to afford 3-methoxy-7- (4,4,5,5-tetramethyl-l,3,2-dioxaborolan-2-yl)benzofuro[3,2-b]pyridine (7.9 g, 51%) as a white solid. MS ESI calculated for C18H20BNO4 [M+H]⁺, 326.15; found, 326.20.

Step-5:

[1330] To a stirred solution of 3-methoxy-7-(4,4,5,5-tetramethyl- 1 ,3,2-dioxaborolan-2- yl)benzofuro[3,2-b]pyridine (14.80 g, 45.51 mmol) in H2O (38 mL) and THF (150 mL) was added NaBO3’4H2O (10.50 g, 68.27 mmol) at room temperature. The resulting mixture was stirred at room temperature for 4 h. The resulting mixture was quenched with water and extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SO4. After filtration, the filtrate was concentrated under reduced pressure to afford 3-methoxybenzofuro[3,2-b]pyridin-7-ol (13 g, crude) as a white solid. MS ESI calculated for C12H9NO3 [M+H]⁺, 216.06; found, 216.15.

Step-6:

[1331] To a stirred solution of 3-methoxybenzofuro[3,2-b]pyridin-7-ol (10 g, 46.46 mmol) DCM (100 mL) was added a solution of KOH (15.64 g, 278.80 mmol) in H2O (66 mL), then TMSCF2Br (28.31 g, 139.40 mmol) was added at 0 °C under nitrogen atmosphere. The resulting mixture was stirred at room temperature for 16 h. The resulting mixture was extracted with CH2CI2. The combined organic layers were washed with brine, dried over anhydrous Na2SC>4. After filtration, the filtrate was concentrated under reduced pressure. The resulting residue was purified by flash column chromatography with 0-31% ethyl acetate in petroleum ether to afford 7-(difluoromethoxy)-3-methoxybenzofuro[3,2-b]pyridine (7.00 g, 56%) as a yellow solid. MS ESI calculated for C13H9F2NO3 [M+H]⁺, 266.06; found, 266.10.

Step-6:

Isomer 1 Isomer 2 Isomer 3 Isomer 4

A63

[1332] To a stirred solution of 7-(difluoromethoxy)-3-methoxybenzofuro[3,2-b]pyridine (700 mg, 2.63 mmol) and 4,4,5,5-tetramethyl-l,3,2-dioxaborolane (1.68 g, 13.19 mmol) in toluene (7 mL) were added N-phenylaniline (1.78 g, 10.55 mmol) and tris(pentafluorophenyl)borane (135 mg, 0.26 mmol) at room temperature under nitrogen atmosphere. The resulting mixture was stirred at 110 °C for 16 h. The resulting mixture was quenched by water and extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SO4. After filtration, the filtrate was concentrated under reduced pressure. The resulting residue was purified by Combi Flash (Biotage Isolera Prime) using a 20 g silica gel column eluted with 0-10% ethyl acetate in petroleum ether to afford a 1 :1 :3:3 mixture of rel-(3R,4aS,9bS)-7-(difluoromethoxy)-3-methoxy-l,2,3,4,4a,9b- hexahydrobenzofuro[3,2-b]pyridine isomer 1 and rel-(3R,4aS,9bS)-7-(difluoromethoxy)-3- methoxy-l,2,3,4,4a,9b-hexahydrobenzofuro[3,2-b]pyridine isomer 2 and rel-(3R,4aR,9bR)-7- (difluoromethoxy)-3-methoxy-l,2,3,4,4a,9b-hexahydrobenzofuro[3,2-b]pyridine isomer 3 and rel-(3R,4aR,9bR)-7-(difluoromethoxy)-3-methoxy-l,2,3,4,4a,9b- hexahydrobenzofuro[3,2-b]pyridine isomer 4 (A63) (500 mg, 69%yield) as a yellow oil. MS ESI calculated for C13H15F2NO3 [M+l]⁺, 272.10; found, 272.15. 'H NMR (400 MHz, DMSO-de) 8 7.41 - 6.93 (m, 2H), 6.78 - 6.54 (m, 2H), 4.74 - 4.55 (m, 2H), 4.15 (d, J= 5.8 Hz, 1H), 3.93 (s, 3H), 3.35 - 3.31 (m, 1H), 2.86 - 2.82 (m, 1H), 2.44 - 2.22 (m, 1H), 1.86 - 1.80 (m, 1H).

Intermediate A63 isomer 1: rel-(3R,4aS,9bS)-7-(difluoromethoxy)-3-methoxy- l,2,3,4,4a,9b-hexahydrobenzofuro[3,2-b]pyridine isomer 1 lsomer

Intermediate A63 isomer 2: rel-(3R,4aS,9bS)-7-(difluoromethoxy)-3-methoxy- l,2,3,4,4a,9b-hexahydrobenzofuro[3,2-b]pyridine isomer 2 and,

Intermediate A63 isomer 3: rel-(3R,4aR,9bR)-7-(difluoromethoxy)-3-methoxy- l,2,3,4,4a,9b-hexahydrobenzofuro[3,2-b]pyridine isomer 3 l^{somer 3} and,

Intermediate A63 isomer 4: rel-(3R,4aR,9bR)-7-(difluoromethoxy)-3-methoxy- l,2,3,4,4a,9b-hexahydrobenzofuro[3,2-b]pyridine isomer 4

[1333] A 1 : 1 :3:3 mixture of rel-(3R,4aS,9bS)-7-(difluoromethoxy)-3-methoxy- l,2,3,4,4a,9b-hexahydrobenzofuro[3,2-b]pyridine isomer 1 and rel-(3R,4aS,9bS)-7- (difhjoromethoxy)-3-methoxy-l,2,3,4,4a,9b-hexahydrobenzofuro[3,2-b]pyridine isomer 2 and rel-(3R,4aS,9bS)-7-(difluoromethoxy)-3-methoxy- 1 ,2, 3, 4, 4a, 9b- hexahydrobenzofuro[3,2-b]pyridine isomer 3 and rel-(3R,4aS,9bS)-7-(difluoromethoxy)-3- methoxy-l,2,3,4,4a,9b-hexahydrobenzofuro[3,2-b]pyridine isomer 4 (A63) (7.7 g) was purified by Prep-HPLC with the following conditions (Column: Xselect CSH OBD Column 30*150 mm, 5 um; Mobile Phase A: Water (0.1% FA), Mobile Phase B: ACN; Flow rate: 60 mL/min; Gradient: isocratic 3--19; Wave Length: 254 nm / 220 nm; RTl(min): 5 minute; RT2(min): 8 minute) to afford fraction A (540 mg, 7%) as a white solid as the first eluting peak at 5 min and fraction B (1.30 g, 18%) as a white solid as the second eluting peak at 8 min.

[1334] The fraction A (540 mg) was separated by prep-chiral SFC with the following conditions: [Column: CHIRALPAK IG, 3*25 cm, 10 pm; Mobile Phase A: CO2, Mobile Phase B: MEOH; Flow rate: 100 mL/min; Gradient: isocratic 20% B; Wave Length: 220 nm; RTl(min): 4.5; RT2(min): 6.35; Sample Solvent: MEOH] to afford rel-(3R,4aS,9bS)-7- (difluoromethoxy)-3-methoxy-l,2,3,4,4a,9b-hexahydrobenzofuro[3,2-b]pyridine, isomer 1 (A63 isomer 1) (150 mg, 27%) as a white solid with retention time at 4.5 minute. And the chiral resolution of fraction A also afford rel-(3R,4aS,9bS)-7-(difluoromethoxy)-3-methoxy- l,2,3,4,4a,9b-hexahydrobenzofuro[3,2-b]pyridine, isomer 2 (A63 isomer 2) (180 mg, 33%) as a white solid with retention time at 6.35 minute.

[1335] rel-(3R,4aS,9bS)-7-(difluoromethoxy)-3-methoxy-l,2,3,4,4a,9b- hexahydrobenzofuro[3,2-b]pyridine, isomer 1 (A63 isomer 1): MS (ESI) calculated for (C13H15F2NO3) [M+H]⁺, 272.10; found, 272.10. 'H NMR (400 MHz, DMSO- ₆) 87.39 - 6.98 (m, 2H), 6.70 - 6.62 (m, 2H), 4.62 (q, J = 6.4 Hz, 1H), 4.34 (d, J = 6.4 Hz, 1H), 3.30 - 3.23 (m, 1H), 3.21 (s, 3H), 2.84 (dd, J= 12.8, 4.0 Hz, 1H), 2.48 - 2.39 (m, 1H), 2.23 - 2.15 (m, 1H), 1.83 - 1.77 (m, 1H). The OMe group is at cis position based on NOESY.

[1336] rel-(3R,4aS,9bS)-7-(difluoromethoxy)-3-methoxy-l,2,3,4,4a,9b- hexahydrobenzofuro[3,2-b]pyridine, isomer 2 (A63 isomer 2): MS (ESI) calculated for (C13H15F2NO3) [M+H]⁺, 272.10; found, 272.10. 'H NMR (400 MHz, DMSO-d₆) 87.39 - 6.98 (m, 2H), 6.70 - 6.64 (m, 2H), 4.62 (q, J = 6.0 Hz, 1H), 4.32 (d, J = 6.8 Hz, 1H), 3.26 - 3.22 (m, 1H), 3.20 (s, 3H), 2.82 (dd, J= 13.2, 4.4 Hz, 1H), 2.45 - 2.39 (m, 1H), 2.23 - 2.17 (m, 1H), 1.82 - 1.74 (m, 1H). The OMe group is at cis position based on NOESY.

[1337] The fraction B (900 mg) was separated by prep-chiral SFC with the following conditions: [Column: CHIRALPAK PAK AD-H, 30*250 mm; Mobile Phase A: CO2, Mobile Phase B: MEOH (0.1% 2M NH3-MEOH); Flow rate: 100 mL/min; Gradient: isocratic 40% B; RTl(min): 2.5; RT2(min): 4; Sample Solvent: MEOH] to afford rel-(3R,4aR, 9bR)-7- (difluoromethoxy)-3-methoxy- 1 ,2,3,4,4a,9b-hexahydrobenzofuro[3,2-b]pyridine, isomer 3 (A63 isomer 3) (400 mg, 44%) as a white solid with retention time at 2.5 minute. And the chiral resolution of fraction B also afford rel-(3R,4aR,9bR)-7-(difluoromethoxy)-3-methoxy- l,2,3,4,4a,9b-hexahydrobenzofuro[3,2-b]pyridine, isomer 4 (A63 isomer 4) (370 mg, 41%) as a white solid with retention time at 4 minute.

[1338] rel-(3R,4aR,9bR)-7-(difhioromethoxy)-3-methoxy-l,2,3,4,4a,9b- hexahydrobenzofuro[3,2-b]pyridine, isomer 3 (A63 isomer 3): MS (ESI) calculated for (C13H15F2NO3) [M+H]⁺, 272.10; found, 272.15. ¹H NMR (400 MHz, DMSO-d₆) 87.37 - 7.00 (m, 2H), 6.67 - 6.65 (m, 2H), 4.68 - 4.63 (m, 1H), 4.15 (d, J = 5.6 Hz, 1H), 3.36 - 3.33 and 3.31 - 3.28 (m, 1H), 3.25 (s, 3H), 2.83 (dd, J = 12.4, 4.4 Hz, 1H), 2.41 - 2.25 (m, 2H), 1.86 - 1.79 (m, 1H).

[1339] rel-(3R,4aR,9bR)-7-(difluoromethoxy)-3-methoxy-l,2,3,4,4a,9b- hexahydrobenzofuro[3,2-b]pyridine, isomer 4 (A63 isomer 4): MS ESI calculated for C13H15F2NO3 [M+H]⁺, 272.10; found, 272.15. 'H NMR (400 MHz, DMSO-d₆) 87.37 - 7.00 (m, 2H), 6.70 - 6.61 (m, 2H), 4.67 - 4.63 (m, 1H), 4.15 (d, J = 6.0 Hz, 1H), 3.37 - 3.33 and 3.32 - 3.28 (m, 1H), 3.25 (s, 3H), 2.83 (dd, J = 12.0, 4.0 Hz, 1H), 2.41 - 2.21 (m, 2H), 1.88 - 1.78 (m, 1H).

Intermediate A64: 1:1 mixture of rel-(2R,4aS,9bS)-7-methoxy-2-methyl-l,2,3,4,4a,9b- hexahydrobenzofuro[3,2-b]pyridine isomer 1 and rel-(2R,4aS,9bS)-7-methoxy-2-methyl- l,2,3,4,4a,9b-hexahydrobenzofuro[3,2-b]pyridine isomer 2

A64

Step-1:

[1340] To a stirred mixture of 2,4-dimethoxyphenylboronic acid (10.00 g, 54.95 mmol) and 2-chloro-3-fluoro-6-methylpyridine (8.00 g, 54.95 mmol) in 1,4-dioxane (100 mL) and H2O (10 mL) were added Pd(dppf)C12-CH₂Cl₂ (4.49 g, 5.49 mmol) and K2CO3 (22.78 g, 164.85 mmol) at 25 °C. The resulting mixture was stirred at 100 °C for 16 h under nitrogen atmosphere. The resulting mixture was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-50% ethyl acetate in petroleum ether to afford 2-(2,4-dimethoxyphenyl)-3-fluoro-6-methylpyridine (12.10 g, 89%) as a pink solid. MS ESI calculated for C14H14FNO2 [M+H]⁺, 248.10; found, 248.05.

[1341] To a stirred solution of 2-(2,4-dimethoxyphenyl)-3-fluoro-6-methylpyridine (12.00 g, 48.53 mmol) in DCM (120 mL) were added BBn (IM in DCM) (48.53 mL, 48.53 mmol) dropwise at 0 °C under nitrogen atmosphere. The resulting mixture was stirred at 0 °C for 2 h. The reaction was quenched with water at 0°C. The resulting mixture was extracted with CH2CI2. The combined organic layers were dried over anhydrous Na2SC>4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-50% ethyl acetate in petroleum ether to afford 2-(3- fhioro-6-methylpyridin-2-yl)-5-methoxyphenol (9.00 g, 79%) as a yellow oil. MS ESI calculated for C13H12FNO2 [M+H]⁺, 234.09; found, 234.10.

Step-3:

[1342] To a stirred mixture of 2-(3-fluoro-6-methylpyridin-2-yl)-5-methoxyphenol (9.00 g, 38.59 mmol) in DMF (30 mL) was added K2CO3 (21.33 g, 154.35 mmol) at 25 °C. The resulting mixture was stirred at 120 °C for 16 h. The reaction was quenched by water and extracted with EtOAc. The combined organic layers were dried over anhydrous Na2SO4.

After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-10% methanol in dichloromethane to afford 7-methoxy-2-methylbenzofuro[3,2-b]pyridine (3.40 g, 41%) as a brown solid. MS ESI calculated for C13H11NO2 [M+H]⁺, 214.08; found, 214.10.

Step-4:

A64

[1343] To a stirred mixture of 7-methoxy-2-methylbenzofuro[3,2-b]pyridine (500 mg, 2.35 mmol) and N-phenylaniline (1.59 g, 9.38 mmol) in toluene (5 mL) were added 4, 4,5,5- tetramethyl-l,3,2-dioxaborolane (1.50 g, 11.73 mmol) and tris(pentafhiorophenyl)borane (120 mg, 0.24 mmol) slowly at 25 °C. The resulting mixture was stirred at 110 °C for 16 h. The mixture was allowed to cool down to room temperature. The mixture was basified with saturated NaHCCh (aq.) to pH 9. The resulting mixture was extracted with EtOAc. The combined organic layers were dried over anhydrous Na2SC>4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by reversed-phase flash column chromatography with 3% to 100% MeCN in Water (lOmmol/L NH4HCO3 to afford a 1:1 mixture of rel-(2R,4aS,9bS)-7-methoxy-2-methyl-l,2,3,4,4a,9b-hexahydrobenzofuro[3,2- b]pyridine isomer 1 and rel-(2R,4aS,9bS)-7-methoxy-2-methyl-l,2,3,4,4a,9b- hexahydrobenzofuro[3,2-b]pyridine isomer 2 (A64) (115 mg, 22%) as a yellow oil. MS ESI calculated for C13H17NO2 [M+l]⁺, 220.13; found, 220.15. 'H NMR (400 MHz, DMSO-J₆) 5 7.17 (d, J = 8.0 Hz, 1H), 6.45 - 6.38 (m, 2H), 4.30 - 4.22 (m, 1H), 3.99 (d, J = 4.8 Hz, 1H), 3.71 (s, 3H), 2.61 - 2.52 (m, 1H), 2.23 - 2.12 (m, 1H), 1.94 - 1.83 (m, 1H), 1.51 - 1.43 (m, 1H), 1.17 - 1.05 (m, 1H), 1.00 - 0.96 (m, 1H), 0.93 (d, J= 6.4 Hz, 3H).

Intermediate A65: rel-(4aS,10bS)-8-chloro-2,3,4,4a,6,10b-hexahydro-lH-isochromeno[4,3- b]pyridine

A65

[1344] To a stirred solution of rel-tert-butyl (4aS,10bS)-8-chloro-2,3,4,4a,6,10b- hexahydro-lH-isochromeno[4,3-b]pyridine-l-carboxylate (intermediate from A25) (1.53 g, 4.73 mmol) in DCM (15 mL) was added Zinc bromide (2.13 g, 9.45 mmol) at 25 °C. The resulting mixture was stirred at 40 °C for 16 h. The resulting mixture was concentrated under reduced pressure and the residue was quenched with water. The mixture was basified to pH 8 with NaHCOs (sat.). The resulting mixture was extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate. After filtration, the filtrate was concentrated under reduced pressure to afford rel-(4aS,10bS)-8-chloro- 2,3,4,4a,6,10b-hexahydro-lH-isochromeno[4,3-b]pyridine (A65) (1.02 g, 96%) as a light brown oil. MS ESI calculated for C12H14CINO [M+H]⁺, 224.08; found, 224.05. 'H NMR (300 MHz, DMSO-d₆) 5 7.31 (d, J= 8.1 Hz, 1H), 7.24 (dd, J = 8.1, 2.1 Hz, 1H), 7.16 (d, J = 2.1 Hz, 1H), 4.86 - 4.62 (m, 2H), 3.55 (q, J = 3.0 Hz, 1H), 3.48 (d, 7= 2.0 Hz, 1H), 2.90 - 2.86 (m, 1H), 2.65 - 2.60 (m, 1H), 2.01 - 1.91 (m, 1H), 1.84 - 1.68 (m, 2H), 1.57 - 1.51 (m, 1H), 1.35 - 1.29 (m, 1H).

Intermediate A66: rel-(4aS, 10bS)-2,3,4,4a,6, 1 Ob-hexahydro- 1 H-isochromeno[4,3- b]pyridine-8-carbonitrile

Step-1:

[1345] A mixture of rel-tert-butyl (4aS,10bS)-8-chloro-2,3,4,4a,6,10b-hexahydro-lH- isochromeno[4,3-b]pyridine-l-carboxylate (from A25) (13.01 g, 40.17 mmol), Zinc cyanide (9.06 g, 77.14 mmol), XPhos-Pd G3 (3.74 g, 4.41 mmol), XPhos (1.92 g, 4.01 mmol) and Zinc (10.38 g, 158.69 mmol) in DMF (130 mL) was stirred at 130 °C for 2 h under nitrogen atmosphere. The reaction mixture was cooled down at room temperature, the mixture was quenched with water and extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and the organic layer was concentrated under vacuum. The resulting residue was purified by normal phase flash chromatography eluted with 0-50% ethyl acetate in petroleum ether to afford rel-tert-butyl (4aS,10bS)-8-cyano-2,3,4,4a,6,10b-hexahydro-lH-isochromeno[4,3-b]pyridine-l-carboxylate (7.6 g, 60%) as a colorless oil. MS ESI calculated for C18H22N2O3 [M+H]⁺, 315.16; found, 315.10.

Step-2:

[1346] To a mixture of rel-tert-butyl (4aS,10bS)-8-cyano-2,3,4,4a,6,10b-hexahydro-lH- isochromeno[4,3-b]pyridine-l-carboxylate (1.70 g, 5.40 mmol) in ethyl acetate (10 mL) was added hydrogen chloride (4.0 M in dioxane) (10 mL) at 0 °C. The mixture was stirred at room temperature for 16 h. The solvents were removed under vacuum to afford rel- (4aS,10bS)-2,3,4,4a,6,10b-hexahydro-lH-isochromeno[4,3-b]pyridine-8-carbonitrile hydrochloride (A66) (1.3 g, 96%) as a white solid. MS ESI calculated for C13H14N2O [M+H]⁺, 215.11; found, 215.15. 'H NMR (400 MHz, DMSO- ₆) 8 10.04 (s, 1H), 8.80 (s, 1H), 7.84 - 7.85 (m, 2H), 7.78 (d, J = 1.2 Hz, 1H), 5.07 - 4.77 (m, 2H), 4.41 (d, J = 9.6 Hz, 1H), 4.00 (d, J= 3.2 Hz, 1H), 3.20 - 3.18 (m, 1H), 3.07 - 3.04 (m, 1H), 2.02 - 1.99 (m, 1H), 1.94 - 1.74 (m, 2H), 1.69 - 1.66 (m, 1H).

Intermediate A67: 1:1 mixture of rel-(2R,4aS,10bS)-8-(difluoromethoxy)-2-methyl- 2,3,4,4a,6,10b-hexahydro-lH-isochromeno[4,3-b]pyridine isomer 1 and rel-(2R,4aS,10bS)-8- (difluoromethoxy)-2-methyl-2,3,4,4a,6,10b-hexahydro-lH-isochromeno[4,3-b]pyridine isomer 2

[1347] To a stirred mixture of methyl 5-(difluoromethoxy)-2-(4,4,5,5-tetramethyl- 1 ,3,2- dioxaborolan-2-yl)benzoate (11.00 g, 33.52 mmol) in 1,4-dioxane (100 mL) and H2O (10 mL) were added K2CO3 (13.90 g, 100.57 mmol), 2-bromo-3-fluoro-6-methylpyridine (7.64 g, 40.23 mmol) and Pd(dppf)Ch (2.74 g, 3.35 mmol). The resulting solution was stirred at 100 °C for 15 h. The reaction mixture was quenched with water and extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SC>4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-20% ethyl acetate in petroleum ether to afford methyl 5-(difluoromethoxy)-2-(3-fluoro-6-methylpyridin-2-yl)benzoate (6.50 g, 81%) as an orange oil. MS ESI calculated for C15H12F3NO3 [M+H]⁺ , 312.26; found, 312.05.

Step-2:

[1348] To a stirred solution of methyl 5-(difluoromethoxy)-2-(3-fluoro-6-methylpyridin-2- yl)benzoate (6.80 g, 21.85 mmol) in THF (68 rnL) was added L1AIH4 (1.66 g, 43.69 mmol) in portions at 0 °C. The resulting solution was stirred at 0 °C for additional 2 h. The reaction was quenched with ice water (1.6 mL) and NaOH (aq., 10%) (1.6 mL) at 0 °C. The resulting mixture was extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous NaiSC . After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-30% ethyl acetate in petroleum ether to afford [5-(difluoromethoxy)-2-(3-fluoro-6-methylpyridin- 2-yl)phenyl]methanol (4.80 g, 88%) as an off-white solid. MS ESI calculated for C14H12F3NO2 [M+H]⁺ , 284.25; found, 284.05.

Step-3:

[1349] To a stirred solution of [5-(difluoromethoxy)-2-(3-fluoro-6-methylpyridin-2- yl)phenyl]methanol (4.80 g, 16.95 mmol) in DMF (50 mL) was added NaH (60% in mineral oil) (0.81 g, 20.25 mmol) at 0 °C. The resulting solution was stirred at 0 °C for 4 h. The reaction was quenched with water at 0 °C and extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SO4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-20% ethyl acetate in petroleum ether to afford 8- (difluoromethoxy)-2-methyl-6H-isochromeno[4,3-b]pyridine (3.50 g, 85%) as a white solid. MS ESI calculated for C14H11F2NO2 [M+H]⁺, 264.03; found, 264.05.

Step-4:

A67

[1350] To a solution of 8-(difluoromethoxy)-2-methyl-6H-isochromeno[4,3-b]pyridine (4.00 g, 15.20 mmol) in AcOH (100 rnL) was added Platinum(IV) oxide (0.35 g, 1.52 mmol). The mixture was hydrogenated at 50 °C under hydrogen pressure (50 atm.) for 18 h. The resulting mixture was filtered through a Celite pad, and the filtrate was concentrated under reduced pressure. The residue was basified with Na2COs (sat.) to pH 7-8. The aqueous layer was extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SC>4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-50% ethyl acetate in petroleum ether to afford a 1:1 mixture of rel-(2R,4aS,10bS)-8-(difluoromethoxy)-2-methyl- 2,3,4,4a,6,10b-hexahydro-lH-isochromeno[4,3-b]pyridine isomer 1 and rel-(2R,4aS,10bS)-8- (difluoromethoxy)-2-methyl-2,3,4,4a,6,10b-hexahydro-lH-isochromeno[4,3-b]pyridine isomer 2 (A67) (1.30 g, 98%) as a yellow oil. MS ESI calculated for C14H17F2NO2 [M+H]⁺ , 270.12; found, 270.15. 'H NMR (400 MHz, DMSO-d₆) 87.37 - 6.99 (m, 3H), 6.88 (d, J = 2.4 Hz, 1H), 4.85 - 4.64 (m, 2H), 3.50 - 3.49 (m, 2H), 2.77 - 2.68 (m, 1H), 2.02 - 1.95 (m, 1H), 1.83 - 1.72 (m, 1H), 1.39 - 1.36 (m, 1H), 1.28 - 1.16 (m, 1H), 0.97 (d, J= 6.4 Hz, 3H).

Intermediate A67 isomer 1: rel-(2R,4aS,10bS)-8-(difluoromethoxy)-2-methyl- 2,3,4,4a,6,10b-hexahydro-lH-isochromeno[4,3-b]pyridine isomer 1

O,, '•p^NH

I orsj

Isomer t Intermediate A67 isomer 2: rel-(2R,4aS,10bS)-8-(difluoromethoxy)-2-methyl-

2,3,4,4a,6,10b-hexahydro-lH-isochromeno[4,3-b]pyridine isomer 2

[1351] A 1 : 1 mixture of rel-(2R,4aS, 10bS)-8-(difluoromcthoxy)-2-mcthyl-2,3,4,4a,6, 10b- hexahydro-lH-isochromeno[4,3-b]pyridine isomer 1 and rel-(2R,4aS,10bS)-8- (difluoromethoxy)-2-methyl-2,3,4,4a,6,10b-hexahydro-lH-isochromeno[4,3-b]pyridine isomer 2 (A67) (1.30 g) was separated by prep-Chiral SFC with the following conditions: [Column: CHIRALPAK IH 5*25 cm, 5 pm; Mobile Phase A: CO₂, Mobile Phase B: MEOH: ACN=1: 1(0.1% 7M NHa-MeOH); Flow rate: 250 mL/min; Gradient (B%): isocratic 30% B; Column Temperature( C): 35; Back Pressure(bar): 100; Wave Length: 220 nm; RTl(min): 4; RT2(min): 7] to afford rel-(2R,4aS,10bS)-8-(difluoromethoxy)-2-methyl-2,3,4,4a,6,10b- hexahydro-lH-isochromeno[4,3-b]pyridine isomer 1 (A67 isomer 1) (580 mg) as a yellow solid with retention time at 4 minute. MS ESI calculated for C14H17F2NO2 [M+H]⁺ , 270.12; found, 270.15. 'H NMR (400 MHz, DMSO-J₆) 87.39 - 7.30 (m, IH), 7.18 (t, J = 72.0 Hz, 1H), 7.04 - 6.97 (m, IH), 6.88 (d, J = 2.6 Hz, IH), 4.82 (d, J = 15.6 Hz, IH), 4.66 (d, J = 15.6 Hz, 1H), 3.54 - 3.47 (m, 2H), 2.78 - 2.67 (m, 1H), 2.02 - 1.92 (m, 1H), 1.85 - 1.70 (m, 1H), 1.40 - 1.36 (m, 1H), 1.28 - 1.13 (m, 1H), 0.97 (d, J = 6.4 Hz, 3H). Absolute stereochemistry was not determined.

[1352] The chiral separation also afford rel-(2R,4aS,10bS)-8-(difluoromethoxy)-2-methyl- 2,3,4,4a,6,10b-hexahydro-lH-isochromeno[4,3-b]pyridine isomer 2 (A67 isomer 2) (560 mg) as a yellow oil with retention time at 7 minute. MS ESI calculated for C14H17F2NO2 [M+H]⁺ , 270.12; found, 270.15. 'H NMR (400 MHz, DMSO-d₆) 6 7.39 - 7.30 (m, 1H), 7.18 (t, J = 72.0 Hz, 1H), 7.04 - 6.97 (m, 1H), 6.88 (d, J = 2.6 Hz, 1H), 4.82 (d, J = 15.6 Hz, 1H), 4.66 (d, J = 15.6 Hz, 1H), 3.54 - 3.47 (m, 2H), 2.78 - 2.67 (m, 1H), 2.02 - 1.92 (m, 1H), 1.85 - 1.70 (m, 1H), 1.40 - 1.36 (m, 1H), 1.28 - 1.13 (m, 1H), 0.97 (d, J = 6.4 Hz, 3H). Absolute stereochemistry was not determined.

Intermediate A68 isomer 1: rel-(4R,4aR,9bR)-4-methyl-7-(trifluoromethyl)-l,2,3,4,4a,9b- hexahydrofuro[2,3-b:4,5-b']dipyridine isomer 1

[1353] To a stirred solution of 3-bromo-2-chloro-6-(trifluoromethyl)pyridine (18.33 g, 70.39 mmol) and (E)-tert-butyl((3-methyl-5-(4,4,5,5-tetramethyl-l,3,2-dioxaborolan-2- yl)pent-4-en-l-yl)oxy)diphenylsilane (32.70 g, 70.39 mmol) in Dioxane (450 mL) and H2O (45 mL) were added K2CO3 (29.19 g, 211.18 mmol) and Pd(dppf)Cl₂-CH₂C12 (5.75 g, 7.04 mmol) at room temperature under nitrogen atmosphere. The resulting mixture was stirred at 100 °C for 16 h. The reaction mixture was quenched by the addition of water and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under vacuum. The resulting residue was purified by normal phase flash chromatography with a 330 g silica gel column eluted with 0-10% ethyl acetate in petroleum ether to afford a 1:1 mixture of (S,E)-3-(5-((tert- butyldiphenylsilyl)oxy)-3-methylpent-l-en-l-yl)-2-chloro-6-(trifluoromethyl)pyridine and (R,E)-3-(5-((tert-butyldiphenylsilyl)oxy)-3-methylpent-l-en-l-yl)-2-chloro-6- (trifhioromethyl)pyridine (33.0 g, 90%) as a yellow oil. MS ESI calculated for C28H₃iClF₃NOSi [M+H]⁺, 518.18; found, 518.15.

Step-2:

[1354] To a stirred solution of tert-butyl carbamate (14.04 g, 119.86 mmol) in propan-1 -ol (197 mL) was added a solution of NaOH (4.26 g, 106.54 mmol) in H2O (130 mL) at room temperature. The mixture was stirred at room temperature for 10 min. Then l,3-dichloro-5,5- dimethylimidazolidine-2, 4-dione (11.81 g, 59.93 mmol) was added to the mixture at room temperature. After stirring at room temperature for 30 min, this was followed by the addition of a solution of (DHQ)2PHAL (supplier: Shanghai Accela ChemBio Co., Ltd. CAS# 140924- 50-1) (2.07 g, 2.66 mmol) in propan-l-ol (27 mL) and a solution of 1:1 mixture of (S,E)-3-(5- ((tert-butyldiphenylsilyl)oxy)-3-methylpent-l-en-l-yl)-2-chloro-6-(trifluoromethyl)pyridine and (R,E)-3-(5-((tert-butyldiphenylsilyl)oxy)-3-methylpent-l-en-l-yl)-2-chloro-6- (trifhioromethyl)pyridine in propan-l-ol (20 mL) at 0 °C. Then Potassium osmate(VI) dihydrate (0.98 g, 2.66 mmol) was added at 0 °C. The resulting mixture was stirred at room temperature for 1 h. The reaction mixture was quenched by the addition of brine and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under vacuum. The residue was purified by normal phase flash chromatography with a 330 g silica gel column eluted with 0-50% ethyl acetate in petroleum ether to afford rel-tert-butyl ((lR,2R,3R)-5-((tert- butyldiphenylsilyl)oxy)-l-(2-chloro-6-(trifluoromethyl)pyridin-3-yl)-2-hydroxy-3- methylpentyl)carbamate isomer 1 (8.0 g, 46%) as a yellow oil as the first eluting peak. MS ESI calculated for C33H42ClF3N2O4Si [M+H]⁺, 651.26; found, 651.15. Absolute stereochemistry was not determined.

[1355] The purification process also affords rel-tert-butyl ((lR,2R,3R)-5-((tert- butyldiphenylsilyl)oxy)-l-(2-chloro-6-(trifluoromethyl)pyridin-3-yl)-2-hydroxy-3- methylpentyl)carbamate isomer 2 (9.5 g, 54%) as a yellow oil as the sencond eluting peak. MS ESI calculated for C33H42ClF3N2O4Si [M+H]⁺, 651.26; found, 651.25. Absolute stereochemistry was not determined.

Step-3:

[1356] To a stirred solution of rel-tert-butyl ((lR,2R,3R)-5-((tert-butyldiphenylsilyl)oxy)- 1 -(2-chloro-6-(trifluoromethyl)pyridin-3-yl)-2-hydroxy-3-methylpentyl)carbamate isomer 1 (5 g, 7.68 mmol) and CS2CO3 (5.00 g, 15.36 mmol) in Toluene (50 mL) were added Pd(OAc)2 (172 mg, 0.77 mmol,) and JohnPhos (458 mg, 1.54 mmol) at room temperature under nitrogen atmosphere. The resulting mixture was stirred at 100 °C for 16 h. The resulting mixture was concentrated under vacuum. The residue was purified by normal phase flash column chromatography with a 120 g silica gel column eluted with 0-10% ethyl acetate in petroleum ether to afford rel-tert-butyl ((2R,3R)-2-((R)-4-((tert- butyldiphenylsilyl)oxy)butan-2-yl)-6-(trifhioromethyl)-2,3-dihydrofuro[2,3-b]pyridin-3- yl)carbamate isomer 1 (870 mg, 18%) as a yellow oil. MS ESI calculated for C33H4iF3N2O4Si [M+H]⁺, 615.28; found, 615.25.

Step-4:

[1357] To a stirred solution of rel-tert-butyl ((2R,3R)-2-((R)-4-((tert- butyldiphenylsilyl)oxy)butan-2-yl)-6-(trifluoromethyl)-2,3-dihydrofuro[2,3-b]pyridin-3- yl)carbamate isomer 1 (840 mg, 1.37 mmol) in THF (9 mL) was added TBAF (715 mg, 2.73 mmol) at room temperature. The resulting mixture was stirred at room temperature for 1 h. The mixture was concentrated under vacuum. The residue was purified by normal phase flash column chromatography with an 40 g silica gel column eluted with 0-50% ethyl acetate in petroleum ether to afford rel-tert-butyl ((2R,3R)-2-((R)-4-hydroxybutan-2-yl)-6- (trifhioromethyl)-2,3-dihydrofuro[2,3-b]pyridin-3-yl)carbamate isomer 1 (410 mg, 80%) as a yellow oil. MS ESI calculated for C17H23F3N2O4 [M+H]⁺, 377.16; found, 377.20.

Step-5:

[1358] To a stirred solution of rel-tert-butyl ((2R,3R)-2-((R)-4-hydroxybutan-2-yl)-6- (trifhioromethyI)-2,3-dihydrofuro[2,3-b]pyridin-3-yl)carbamate isomer 1 (410 mg, 1.09 mmol) in toluene (5 mL) was added 2-(tributyl-A,⁵-phosphaneylidene)acetonitrile (CAS No. 157141-27-0) (526 mg, 2.18 mmol) at room temperature under nitrogen atmosphere. The resulting mixture was stirred at 100 °C for 16 h. The reaction mixture was concentrated under vacuum. The residue was purified by normal phase flash column chromatography with an 40 g silica gel column eluted with 0-15% ethyl acetate in petroleum ether to afford rel-tert-butyl (4R,4aR,9bR)-4-methyl-7-(trifluoromethyl)-3,4,4a,9b-tetrahydrofuro[2,3-b:4,5-b']dipyridine- l(2H)-carboxylate isomer 1 (330 mg, 83%) as a yellow oil. MS ESI calculated for C17H21F3N2O3 [M+H]⁺, 359.15; found, 359.15.

Step-6:

[1359] A mixture of rel-tert-butyl (4R,4aR,9bR)-4-methyl-7-(trifluoromethyl)-3,4,4a,9b- tetrahydrofuro[2,3-b:4,5-b']dipyridine-l(2H)-carboxylate isomer 1 (330 mg, 0.92 mmol) and HC1 (4.0 M in ethyl acetate) (4 mL) was stirred at room temperature for 2 h. The mixture was concentrated under vacuum to afford rel-(4R,4aR,9bR)-4-methyl-7-(trifluoromethyl)- l,2,3,4,4a,9b-hexahydrofuro[2,3-b:4,5-b']dipyridine hydrochloride isomer 1 (A68 isomer 1) (crude, 285 mg) as a white solid. MS ESI calculated for C12H13F3N2O [M+H]⁺, 259.10; found, 259.10. ¹H NMR (400 MHz, DMSO) 8 10.62 (s, 1H), 8.73 (s, 1H), 8.23 (d, J = 7.6 Hz, 1H), 7.62 (d, J = 7.6 Hz, 1H), 5.09 - 4.93 (m, 1H), 4.88 - 4.76 (m, 1H), 3.24 - 3.08 (m, 1H), 3.06 - 2.90 (m, 1H), 2.33 - 2.19 (m, 1H), 1.83 - 1.69 (m, 1H), 1.60 - 1.43 (m, 1H), 1.21 (d, J = 6.8 Hz, 3H). Absolute stereochemistry was not determined.

Intermediate A68 isomer 2: rel-(4R,4aR,9bR)-4-methyl-7-(trifluoromethyl)-l,2,3,4,4a,9b- hexahydrofuro[2,3-b:4,5-b']dipyridine isomer 2 Step 1:

[1360] A solution of rel-tert-butyl ((lR,2R,3R)-5-((tert-butyldiphenylsilyl)oxy)-l-(2-chloro- 6-(trifluoromethyl)pyridin-3-yl)-2-hydroxy-3-methylpentyl)carbamate isomer 2 (8 g, 12.28 mmol) Pd(OAc)2 (0.28 g, 1.22 mmol), JohnPhos (0.73 g, 2.45 mmol) and CS2CO3 (10.01 g, 30.71 mmol) in toluene (80 mL) was stirred at 100 °C for 16 h under nitrogen atmosphere. The resulting mixture was concentrated under reduced pressure. The resulting residue was purified by normal phase flash chromatography using a 330 g silica gel column eluted with 0-15% ethyl acetate in petroleum ether to afford rel-tert-butyl ((2R,3R)-2-((R)-4-((tert- butyldiphenylsilyl)oxy)butan-2-yl)-6-(trifhioromethyl)-2,3-dihydrofuro[2,3-b]pyridin-3- yl)carbamate isomer 2 (1.3 g, 17%) as a yellow oil. MS ESI calculated for (CssHwFs^CLSi) [M+H]⁺, 615.28; found, 615.30.

Step 2: isomer 2 isomer 2

[1361] A solution of rel-tert-butyl ((2R,3R)-2-((R)-4-((tert-butyldiphenylsilyl)oxy)butan-2- yl)-6-(trifhioromethyl)-2,3-dihydrofuro[2,3-b]pyridin-3-yl)carbamate isomer 2 (1.3 g, 2.11 mmol) and TBAF (0.83g, 3.17 mmol) in THF (10 mL) was stirred at room temperature for 2 h. The resulting mixture was concentrated under reduced pressure. The resulting residue was purified by normal phase flash chromatography using a 40 g silica gel column eluted with 0- 50% ethyl acetate in petroleum ether to afford rel-tert-butyl ((2R,3R)-2-((R)-4-hydroxybutan- 2-yl)-6-(trifhioromethyl)-2,3-dihydrofuro[2,3-b]pyridin-3-yl)carbamate isomer 2 (600 mg, 75%) as a white solid. MS ESI calculated for C17H23F3N2O4 [M+H]⁺, 377.16; found, 377.20.

Step 3:

[1362] A solution of rel-tert-butyl ((2R,3R)-2-((R)-4-hydroxybutan-2-yl)-6- (trifluoromethyl)-2,3-dihydrofuro[2,3-b]pyridin-3-yl)carbamate isomer 2 (600 mg, 1.59 mmol) and 2-(tributyl-A.⁵-phosphaneylidene)acetonitrile (CAS No. 157141-27-0) (769 mg, 3.18 mmol) in toluene (10 mL) was stirred at 100°C for 16 h under nitrogen atmosphere. The resulting mixture was concentrated under reduced pressure. The resulting residue was purified by reverse phase flash column chromatography, eluted with 5-70% acetonitrile in water (10 mM NH4HCO3) to afford rel-tert-butyl (4R,4aR,9bR)-4-methyl-7- (trifhioromethyl)-3,4,4a,9b-tetrahydrofuro[2,3-b:4,5-b']dipyridine-l(2H)-carboxylate isomer 2 (340 mg, 66%) as a yellow oil. MS ESI calculated for C17H21F3N2O3 [M+H]⁺, 359.15; found, 359.10.

Step 4:

[1363] A mixture of tert-butyl (4R*,4aS,9bS)-4-methyl-7-(trifluoromethyl)-3,4,4a,9b- tetrahydrofuro[2,3-b:4,5-b']dipyridine-l(2H)-carboxylate (340 mg, 0.94 mmol) and hydrogen chloride (4.0 M in ethyl acetate) (5 mL) was stirred at room temperature for 1 h. The resulting mixture was concentrated under vacuum to afford rel-(4R,4aR,9bR)-4-methyl-7- (trifluoromethyl)-l,2,3,4,4a,9b-hexahydrofuro[2,3-b:4,5-b']dipyridine hydrochloride isomer 2 (301 mg, crude) as a fight yellow solid. MS ESI calculated for C12H13F3N2O [M+H]⁺, 259.10; found, 258.95. 'H NMR (400 MHz, DMSC s) 8 10.81 (s, 1H), 9.36 (s, 1H), 8.35 (d, 7 = 7.4 Hz, 1H), 7.62 (d, 7 = 7.6 Hz, 1H), 5.14 - 5.13 (m, 1H), 4.71 (t, 7 = 7.6 Hz, 1H), 3.15 - 3.14 (m, 2H), 2.21 - 2.18 (m, 1H), 1.89 - 1.85 (m, 1H), 1.58 - 1.51 (m, 1H), 1.16 (d, 7= 6.6 Hz, 3H). Absolute stereochemistry was not determined.

Intermediate A69: (3R,4aS,9aR)-3-methyl-2,3,4,4a,9,9a-hexahydroindeno[2, 1- b] [ 1 ,4] oxazine-7-carbonitrile

[1364] To a stirred mixture of (3R,4aS,9aR)-7-chloro-3-methyl-2,3,4,4a,9,9a- hexahydroindeno[2,l-b][l,4]oxazine (1.0 g, 4.47 mmol), Zn(CN)2 (584 mg, 8.94 mmol), Zinc (1169 mg, 17.88 mmol) in DMF (15 mL) were added XPhos Pd G3 (567 mg, 0.67 mmol) and XPhos (319 mg, 0.67 mmol). The resulting mixture was stirred at 130 °C for 3 h under nitrogen atmosphere. The resulting mixture was filtered, the filter cake was washed with MeCN. The filtrate was concentrated under reduced pressure. The residue was purified by reverse phase flash column chromatography with 5-90% ACN in water to afford (3R,4aS,9aR)-3-methyl-2,3,4,4a,9,9a-hexahydroindeno[2,l-b][l,4]oxazine-7-carbonitrile (A69) (320 mg, 33% yield) as a yellow oil. MS ESI calculated for C13H14N2O [M+H]⁺, 215.11; found, 215.10. 'H NMR (300 MHz, DMSO- ₆) 87.76 - 7.46 (m, 3H), 4.25 (d, J = 3.6 Hz, 1H), 4.13 (t, J= 3.6 Hz, 1H), 3.42 (dd, J= 10.8, 3.0 Hz, 1H), 3.06 - 2.88 (m, 3H), 2.73 (d, 7 = 16.5 Hz, 1H), 0.86 (d, 7= 6.3 Hz, 3H). Intermediate A70 isomer 1: rel-(3R,4aS,10bS)-8-(difluoromethoxy)-3-fluoro-

2,3,4,4a,6,10b-hexahydro-lH-isochromeno[4,3-b]pyridine isomer 1 isomer !

Intermediate A70 isomer 2: rel-(3R,4aS,10bS)-8-(difluoromethoxy)-3-fluoro-

2,3,4,4a,6,10b-hexahydro-lH-isochromeno[4,3-b]pyridine isomer 2 and,

Intermediate A70 isomer 3: rel-(3R,4aS,10bS)-8-(difluoromethoxy)-3-fluoro-

2,3,4,4a,6,10b-hexahydro-lH-isochromeno[4,3-b]pyridine isomer 3 and,

Intermediate A70 isomer 4: rel-(3R,4aS,10bS)-8-(difluoromethoxy)-3-fluoro-

2,3,4,4a,6,10b-hexahydro-lH-isochromeno[4,3-b]pyridine isomer 4

Isomer 4

Step-1:

[1365] To a stirred mixture of 2-bromo-5-hydroxybenzaldehyde (12 g, 59.69 mmol) in DCM (200 mL) was added KOH (20%, aq.) (200 mL, 358.17 mmol) at 0 °C, then TMSCF2Br (24.25 g, 119.39 mmol) was added dropwise at 0 °C. The resulting mixture was stirred at room temperature for 2 h. The mixture was extracted with DCM. The organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under vacuum. The residue was purified by flash column chromatography with 10-30% ethyl acetate in petroleum ether to afford 2-bromo-5-(difluoromethoxy)benzaldehyde (13 g, 86%) as a light yellow oil. MS ESI calculated for CsHsBrF2O2 [M+H]⁺, 250.94, 252.94; found, 250.90, 252.95.

Step-2:

[1366] To a stirred mixture of 2-bromo-5-(difluoromethoxy)benzaldehyde (5 g, 19.91 mmol) in THF (50 mL) was added NaBH4 (1.51 g, 39.83 mmol) in portions at 0 °C. The resulting mixture was stirred at room temperature for 16 h. The reaction mixture was quenched by the addition of water at 0 °C. The mixture was extracted with DCM, washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under vacuum to afford (2-bromo-5-(difluoromethoxy)phenyl)methanol (4.9 g, crude) as a white solid. MS ESI calculated for C8H₇BrF₂O₂ [M+l]⁺, 252.96, 254.96; found, 252.85, 254.85.

Step-3:

[1367] To a stirred mixture of (2-bromo-5-(difluoromethoxy)phenyl)methanol (4.9 g, 19.36 mmol) in DCM (50 mL) were added TEA (5.87 g, 58.08 mmol) and Ac₂O (2.17 g, 21.30 mmol) at 0 °C. The resulting mixture was stirred at room temperature for 2 h. The mixture was diluted with DCM and washed with brine. The organic layer was dried over anhydrous sodium sulfate, filtered, and concentrated under vacuum. The residue was purified by flash column chromatography with 10-30% ethyl acetate in petroleum ether to afford 2-bromo-5- (difluoromethoxy)benzyl acetate (4.9 g, 85%) as a white solid. MS ESI calculated for CioH₉BrF₂0₃ [M+l]⁺, 294.97, 296.97; found, 294.95, 297.00.

Step-4:

[1368] To a stirred mixture of 2-bromo-5-(difluoromethoxy)benzyl acetate (4.9 g, 16.60 mmol), AcOK (4.89 g, 49.81 mmol) and BPD (4.64 g, 18.26 mmol) in 1,4-dioxane (50 mL) was added Pd(dppf)Cl₂ (0.92 g, 1.66 mmol) at room temperature. The resulting mixture was stirred at 80 °C for 2 h under nitrogen atmosphere. The mixture was cooled to room temperature, this was followed by the addition of a mixture of K₂CO₃ (5.94 g, 42.96 mmol), 2-bromo-3,5-difluoropyridine (3.33 g, 17.18 mmol) and Pd(dppf)Cl₂ (1.17 g, 1.43 mmol) in 1,4-dioxane (50 mL) and H₂O (5 mL) at room temperature under nitrogen atmosphere. The resulting mixture was stirred at 80 °C for 2 h. The mixture was diluted with ethyl acetate, washed with brine. The organic layer was dried over anhydrous sodium sulfate, filtered, and concentrated under vacuum. The residue was purified by flash column chromatography with 10-30% ethyl acetate in petroleum ether to afford 5-(difluoromethoxy)-2-(3,5- difluoropyridin-2-yl)benzyl acetate (2.1 g, 44%) as a yellow oil. MS ESI calculated for C15H11F4NO3 [M+H]⁺, 330.07; found, 330.05.

Step-5:

[1369] To a stirred mixture of 5-(difluoromethoxy)-2-(3,5-difluoropyridin-2-yl)benzyl acetate (2.1 g, 6.37 mmol) in H2O (6 mL) and THF (18 mL) was added LiOH (0.61 g, 25.51 mmol) at room temperature. The resulting mixture was stirred at room temperature for 48 h. The aqueous solution was quenched with water and extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SC>4. After filtration, the filtrate was concentrated under reduced pressure to afford (5-(difluoromethoxy)-2-(3,5- difhioropyridin-2-yl)phenyl)methanol (1.6 g, crude) as a yellow oil. MS ESI calculated for C13H9F4NO2 [M+l]⁺, 288.06; found, 288.05.

Step-6:

[1370] To a solution of (5-(difhioromethoxy)-2-(3,5-difluoropyridin-2-yl)phenyl)methanol (1.6 g, 5.57 mmol) in THF (20 mL) was added NaH (0.27 g, 6.75 mmol, 60% in mineral oil) in portions at 0 °C. The mixture was allowed to warm at room temperature and stirred for 16 h. The reaction mixture was quenched by water and extracted with DCM, dried over anhydrous sodium sulfate, filtered, and concentrated under vacuum. The residue was purified by flash column chromatography with 20-50% ethyl acetate in petroleum ether to afford 8- (difluoromethoxy)-3-fluoro-6H-isochromeno[4,3-b]pyridine (1.3 g, 87%) as a white solid. MS ESI calculated for C13H8F3NO2 [M+H]⁺, 268.05; found, 268.05.

Step-7:

[1371] To a solution of 8-(difluoromethoxy)-3-fluoro-6H-isochromeno[4,3-b]pyridine (500 mg, 1.87 mmol) in THF (5 mL) were added HC1 (con.) (163 mg, 4.49 mmol) and H2O (5 mL). then Pd(OH)2/C (5%) (500 mg, 3.56 mmol) was addded. The mixture was hydrogenated at room temperature under hydrogen atmosphere (50 atm.) for 24 h. The mixture was filtered through a Celite pad. The filtrate was concentrated under reduced pressure. The crude product was purified by Prep-HPLC with the following conditions (Column: Xselect CSH C18 OBD Column 30*150 mm 5pm; Mobile Phase A: Water (0.1% FA), Mobile Phase B: ACN; Flow rate: 60 mL/min; Gradient: 5% B to 5% B in 2 min, 3% B to 16% B in 15 min;

Wave Length: 254/220 ran; RTl(min): 4.5-10.2) to afford fraction A (150 mg) as a white solid as the first eluting peak and fraction B (50 mg) as a white solid as the second eluting peak.

[1372] The fraction A was purified by Prep-Chiral-HPLC with the following conditions (Column: CHIRALPAK IG, 2*25 cm, 5 pm; Mobile Phase A: Hex (0.5% 2M NH₃-MeOH), Mobile Phase B: MEOH : DCM=1:1— HPLC; Flow rate: 20 mL/min; Gradient: 15% B to 15% B in 20 min; Wave Length: 220/254 nm; RTl(min): 12.85; RT2(min): 15.54; Sample Solvent: EtOH : DCM=1: 1— HPLC; Injection Volume: 0.2 mL; Number Of Runs: 18) to afford rel-(3R,4aS,10bS)-8-(difluoromethoxy)-3-fluoro-2,3,4,4a,6,10b-hexahydro-lH- isochromeno[4,3-b]pyridine isomer 1 (A70 isomer 1) (50 mg, 33%) as a white solid with retention time at 12.85 min. and rel-(3R,4aS,10bS)-8-(difluoromethoxy)-3-fluoro- 2,3,4,4a,6,10b-hexahydro-lH-isochromeno[4,3-b]pyridine isomer 2 (A70 isomer 2) (50 mg, 33%) as a white solid with retention time at 15.54 min.

[1373] rel-(3R,4aS, 10bS)-8-(difhioromethoxy)-3-fluoro-2,3,4,4a,6, 1 Ob-hexahydro- 1 H- isochromeno[4,3-b]pyridine isomer 1 (A70 isomer 1): MS ESI calculated for C13H14F3NO2 [M+H]⁺, 274.10; found, 274.15. 'H NMR (300 MHz, DMSO-d₆) 5 (ppm) 8 7.45 - 6.99 (m, 3H), 6.94 - 6.87 (m, 1H), 4.78 (d, J= 15.6 Hz, 1H), 4.69 - 4.45 (m, 2H), 3.65 - 3.59 (m, 1H),

3.56 (s, 1H), 3.06 - 2.79 (m, 2H), 2.21 - 1.84 (m, 3H). Absolute stereochemistry was not determined.

[1374] rel-(3R,4aS, 10bS)-8-(difhioromethoxy)-3-fluoro-2,3,4,4a,6, 1 Ob-hexahydro- 1 H- isochromeno[4,3-b]pyridine isomer 2 (A70 isomer 2): MS ESI calculated for C13H14F3NO2 [M+H]⁺, 274.10; found, 274.15. 'H NMR (300 MHz, DMSO-d₆) 3 (ppm) 8 7.47 - 6.97 (m, 3H), 6.95 - 6.87 (m, 1H), 4.78 (d, J= 15.6 Hz, 1H), 4.69 - 4.45 (m, 2H), 3.67 - 3.59 (m, 1H),

3.57 (s, 1H), 3.03 - 2.79 (m, 2H), 2.23 - 1.95 (m, 3H). Absolute stereochemistry was not determined.

[1375] The fraction B (300 mg) was purified by Prep-Chiral-HPLC with the following conditions (Column: CHIRALPAK IF, 2*25 cm, 5 pm; Mobile Phase A: Hex (0.5% 2M NH₃-MeOH)— HPLC, Mobile Phase B: EtOH : DCM=1:1-HPLC; Flow rate: 20 mL/min; Gradient: 15% B to 15% B in 13 min; Wave Length: 220/254 nm; RTl(min): 8.91;

RT2(min): 11.83; Sample Solvent: EtOH : DCM=1:1— HPLC; Injection Volume: 0.5 mL; Number Of Runs: 10) to afford rel-(3R,4aS,10bS)-8-(difluoromethoxy)-3-fluoro- 2,3,4,4a,6,10b-hexahydro-lH-isochromeno[4,3-b]pyridine isomer 3 (A70 isomer 3) (70 mg, 23%) as a white solid with retention time at 8.91 min. and rel-(3R,4aS,10bS)-8- (difluoromethoxy)-3-fluoro-2, 3, 4, 4a, 6,1 Ob-hexahydro- 1H-isochromeno[4,3-b]pyri dine isomer 4 (A70 isomer 4) (70 mg, 23%)as a white solid with retention time at 11.83 min.

[1376] rel-(3R,4aS,10bS)-8-(difhioromethoxy)-3-fluoro-2,3,4,4a,6,10b-hexahydro-lH- isochromeno[4,3-b]pyridine isomer 3 (A70 isomer 3): MS ESI calculated for C12H15NO [M4-H]⁺, 190.12; found, 190.05. 'H NMR (300 MHz, DMSO-d₆) 8 (ppm) 8 7.60 (d, J= 8.7 Hz, 1H), 7.47 - 6.92 (m, 2H), 6.91 - 6.89 (m, 1H), 4.82 (t, J = 16.5 Hz, 2H), 4.72 - 4.42 (m, 1H), 3.38 - 3.31 (m, 1H), 3.29 - 3.13 (m, 2H), 2.68 - 2.55 (m, 2H), 2.49 - 2.43 (m, 1H), 1.70

- 1.52 (m, 1H). Absolute stereochemistry was not determined.

[1377] rel-(3R,4aS, 10bS)-8-(difluoromethoxy)-3-fluoro-2,3,4,4a,6, 1 Ob-hexahydro- 1 H- isochromeno[4,3-b]pyridine isomer 4 (A70 isomer 4): MS ESI calculated for C12H15NO [M+H]⁺, 190.12; found, 190.05. ^XH NMR (300 MHz, DMSO-J₆) 3 (ppm) 8 7.60 (d, J= 8.4 Hz, 1H), 7.47 - 6.92 (m, 2H), 6.91 - 6.89 (m, 1H), 4.82 (t, J= 16.2 Hz, 2H), 4.72 - 4.42 (m, 1H), 3.38 - 3.31 (m, 1H), 3.29 - 3.13 (m, 2H), 2.68 - 2.55 (m, 2H), 2.49 - 2.43 (m, 1H), 1.70 - 1.52 (m, 1H). Absolute stereochemistry was not determined.

Intermediate A71: rel-(4aR,9bR)-7-(difluoromethoxy)-l,2,3,4,4a,9b-hexahydrofuro[2,3- b:4,5-b']dipyridine

Step-1:

[1378] To a stirred solution of 5-bromo-6-chloropyridin-2-amine (70 g, 168.70 mmol) in H2SO4 (1400 mL, 20%) was added a solution of NaNCh (46.56 g, 337.41 mmol) in H2O (700 mL) dropwise at 0 °C. The resulting mixture was stirred at 0 °C for 1 h. The precipitated solids were collected by filtration and washed with water. The filter cake was concentrated under reduced pressure to afford 5-bromo-6-chloropyridin-2-ol (68 g, crude) as a light brown solid. MS ESI calculated for C₅H₃BrClNO [M+H]⁺, 207.91, 209.91; found, 207.95, 209.95.

Step-2:

[1379] To a stirred solution of 5-bromo-6-chloropyridin-2-ol (62 g, 297.45 mmol) in DMF (620 mL) and H₂O (62 mL) were sequentially added K2CO3 (82.22 g, 594.89 mmol) and sodium 2-chloro-2,2-difluoroacetate (68.02 g, 446.17 mmol) at 0 °C. The mixture was stirred at 100 °C for 2 h. The resulting mixture was filtered, the filter cake was washed with EtOAc. The filtrate was quenched with water. The aqueous layer was extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na₂SO4. The residue was purified by silica gel column chromatography, eluted with PE / DCM (10: 1) to afford 3- bromo-2-chloro-6-(difluoromethoxy)pyridine (71.2 g, 92%) as a colorless oil. MS ESI calculated for C6H₃BrClF₂NO [M+H]⁺, 257.91, 259.90; found, 257.95, 259.95.

Step-3:

[1380] To a stirred solution of 3-bromo-2-chloro-6-(difluoromethoxy)pyridine (33 g, 127.68 mmol) and (E)-tert-butyldiphenyl((5-(4,4,5,5-tetramethyl-l,3,2-dioxaborolan-2- yl)pent-4-en-l-yl)oxy)silane (57.52 g, 127.68 mmol) in 1,4-dioxane (330 mL) and H₂O (33 mL) were added K2CO3 (52.94 g, 383.05 mmol) and Pd(dppf)Cl₂-CH₂C12 (10.43 g, 12.77 mmol) at room temperature. The resulting mixture was stirred at 100 °C for 2 h under nitrogen atmosphere. The resulting mixture was quenched with water and extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na₂SC>4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with CH₂C1₂ / PE (1:10) to afford (E)-3-(5- ((tert-butyldiphenylsilyl)oxy)pent-l-en-l-yl)-2-chloro-6-(difluoromethoxy)pyridine (36.4 g, 57%) as a yellow oil. MS ESI calculated for C₂7H3oClF₂N0₂Si [M+H]⁺, 502.17; found, 502.15.

[1381] To a stirred mixture of B0CNH2 (15.87 g, 135.64 mmol, 0.4 M in n-PrOH) and NaOH (5.42 g, 135.64 mmol, 0.4 M aq.) was added DCDMH (26.72 g, 135.64 mmol) in portions at 0 °C. The resulting solution was stirred at 25 °C for 0.5 h. Then (DHQ)2PHAL (supplier: Shanghai Accela ChemBio Co., Ltd. CAS# 140924-50-1) (3.52 g, 4.52 mmol, 0.1 M in n-PrOH) was added dropwise at 0 °C. The resulting mixture was stirred at 0 °C for additional 20 min. Then (E)-3-(5-((tert-butyldiphenylsilyl)oxy)pent-l-en-l-yl)-2-chloro-6- (difluoromethoxy)pyridine (22.7 g, 45.21 mmol) and K2OSO4-2H2O (1.67 g, 4.52 mmol) were added at 0 °C. The resulting mixture was stirred at room temperature for additional 16 h. The resulting mixture was quenched with water. The resulting mixture was extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SC>4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with PE / EtOAc (5:1) to afford rel-tert-butyl ((lS,2S)-5-((tert-butyldiphenylsilyl)oxy)-l-(2-chloro-6-(difluoromethoxy)pyridin-3-yl)-2- hydroxypentyl)carbamate (12.2 g, 42%) as a yellow solid. MS ESI calculated for C32H4iClF2N₂O₅Si [M+H]⁺, 635.24; found, 635.25.

Step-5:

[1382] To a stirred solution of rel-tert-butyl ((lS,2S)-5-((tert-butyldiphenylsilyl)oxy)-l-(2- chloro-6-(difluoromethoxy)pyridin-3-yl)-2-hydroxypentyl)carbamate (4.4 g, 6.93 mmol) in THF (45 mL) was added TBAF (3.62 g, 13.85 mmol) in portions at 0 °C. The resulting solution was stirred at 25 °C for 2 h. The resulting mixture was quenched with water and extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SO4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with PE / EtOAc (1:1) to afford rel-tert-butyl ((lS,2S)-l-(2-chloro-6-(difluoromethoxy)pyridin-3-yl)-2,5- dihydroxypentyl)carbamate (1.3 g, 47%) as a white solid. MS ESI calculated for C16H23CIF2N2O5 [M+H]⁺, 397.13; found, 397.15.

Step-6:

[1383] To a stirred solution of rel-tert-butyl ((lS,2S)-l-(2-chloro-6- (difhioromethoxy)pyridin-3-yl)-2,5-dihydroxypentyl)carbamate (1.3 g, ?>. 1 mmol) and imidazole (0.45 g, 6.55 mmol) in DCM (13 mL) was added TBSC1 (0.74 g, 4.91 mmol) at 0 °C. The resulting solution was stirred at 25 °C for 2 h. The resulting mixture was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with PE / EtOAc (1:1) to afford rel-tert-butyl ((lS,2S)-5-((tert- butyldimethylsilyl)oxy)-l-(2-chloro-6-(difluoromethoxy)pyridin-3-yl)-2- hydroxypentyl)carbamate (1.3 g, 77%) as a colorless oil. MS ESI calculated for C22H₃7ClF₂N2O5Si [M+H]⁺, 511.21; found, 511.20.

Step-7:

[1384] To a stirred solution of rel-tert-butyl ((lS,2S)-5-((tert-butyldimethylsilyl)oxy)-l-(2- chloro-6-(difhioromethoxy)pyridin-3-yl)-2-hydroxypentyl)carbamate (1.3 g, 2.54 mmol) and imidazole (0.35 g, 5.09 mmol) in DCM (13 mL) was added TBDPSC1 (1.05 g, 3.81 mmol) at 0 °C. The resulting solution was stirred at 25 °C for 16 h. The resulting mixture was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with CH2CI2 / PE (1:1) to afford rel-tert-butyl ((lS,2S)-5-((tert- butyldimethylsilyl)oxy)-2-((tert-butyldiphenylsilyl)oxy)-l-(2-chloro-6- (difluoromethoxy)pyridin-3-yl)pentyl)carbamate (380 mg, 20%) as a colorless oil. MS ESI calculated for C₃8H55ClF2N2O₅Si2 [M+H]⁺, 749.33; found, 749.35.

Step-8:

[1385] To a stirred solution of rel-tert-butyl ((lS,2S)-5-((tert-butyldimethylsilyl)oxy)-2- ((tert-butyldiphenylsilyl)oxy)-l-(2-chloro-6-(difluoromethoxy)pyridin-3-yl)pentyl)carbamate (330 mg, 0.44 mmol) in methanol (3 mL) was added TsOH (15 mg, 0.09 mmol) at room temperature. The resulting solution was stirred at 25 °C for 2 h. The resulting mixture was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with PE / EtOAc (1:1) to afford rel-tert-butyl ((lS,2S)-2-((tert- butyldiphenylsilyl)oxy)-l-(2-chloro-6-(difluoromethoxy)pyridin-3-yl)-5- hydroxypentyl)carbamate (220 mg, 78%) as a colorless oil. MS ESI calculated for C32H₄iClF2N2O₅Si [M+H]⁺, 635.24; found, 635.15.

Step-9:

[1386] To a stirred solution of rel-tert-butyl ((lS,2S)-2-((tert-butyldiphenylsilyl)oxy)-l-(2- chloro-6-(difluoromethoxy)pyridin-3-yl)-5-hydroxypentyl)carbamate (200 mg, 0.31 mmol) in toluene (4 mL) was added 2-(tributyl- ,⁵-phosphaneylidene)acetonitrile (CAS No. 157141-27- 0) (152 mg, 0.63 mmol) dropwise at room temperature under nitrogen atmosphere. The resulting solution was stirred at 110 °C for 2 h. The resulting mixture was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with PE / EtOAc (10:1) to afford rel-tert-butyl (2S,3S)-3-((tert-butyldiphenylsilyl)oxy)-2-(2- chloro-6-(difluoromethoxy)pyridin-3-yl)piperidine-l-carboxylate (150 mg, 77%) as a white solid. MS ESI calculated for C32H₃9ClF₂N2O4Si [M+H]⁺, 617.23; found, 617.10.

Step- 10:

[1387] To a stirred solution of rel-tert-butyl (2S,3S)-3-((tert-butyldiphenylsilyl)oxy)-2-(2- chloro-6-(difluoromethoxy)pyridin-3-yl)piperidine-l-carboxylate (150 mg, 0.24 mmol) in THF (2 mL) was added TBAF (127 mg, 0.48 mmol) at room temperature. The mixture was stirred at room temperature for 2 h. The resulting mixture was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with PE / EtOAc (5:1) to afford rel-tert-butyl (2S,3S)-2-(2-chloro-6-(difluoromethoxy)pyridin-3-yl)-3- hydroxypiperidine-1 -carboxylate (60 mg, 65%) as a colorless oil. MS ESI calculated for C16H21CIF2N2O4 [M+H]⁺, 379.12; found, 379.05.

Step-11:

[1388] To a stirred solution of rel-tert-butyl (2S,3S)-2-(2-chloro-6- (difluoromethoxy)pyridin-3-yl)-3-hydroxypiperidine-l-carboxylate (55 mg, 0.14 mmol) in THF (1 mL) was added NaH (2 mg, 0.06 mmol, 60% in mineral oil) at 0 °C. The resulting solution was stirred at 0 °C for 1 h. The reaction was quenched by the addition of ice water at 0 ° C. The resulting mixture was extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous NazSC . After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with PE / EtOAc (5:1) to afford rel-tert-butyl (4aS,9bS)-7- (difluoromethoxy)-3,4,4a,9b-tetrahydrofuro[2,3-b:4,5-b']dipyridine- 1 (2H)-carboxylate (25 mg, 50%) as a white solid. MS ESI calculated for C16H20F2N2O4 [M+H]⁺, 343.14; found, 343.10.

Step- 12:

[1389] A mixture of rel-tert-butyl (4aS,9bS)-7-(difluoromethoxy)-3,4,4a,9b- tetrahydrofuro[2,3-b:4,5-b']dipyridine-l(2H)-carboxylate (25 mg, 0.12 mmol) and HC1 (4.0 M in 1,4-dioxane) (1 mL) was stirred at 25 ⁰ C for 1 h. The resulting mixture was concentrated under reduced pressure to afford rel-(4aS,9bS)-7-(difluoromethoxy)- l,2,3,4,4a,9b-hexahydrofuro[2,3-b:4,5-b']dipyridine hydrochloride (A71) (40 mg, crude) as a white solid. MS ESI calculated for C11H12F2N2O2 [M+H]⁺, 243.09; found, 243.10. NMR (400 MHz, DMSO-A) 5 9.95 (br, 1H), 8.59 (br, 1H), 8.02 (d, J= 8.0 Hz 1H), 7.65 (t, J = 71.6 Hz, 1H), 6.74 (d, J = 8.0 Hz 1H), 4.94 - 4.89 (m, 1H), 4.87 - 4.82 (m, 1H), 3.18 - 3.07 (m, 1H), 2.99 - 2.88 (m, 1H), 2.29 - 2.19 (m, 1H), 2.11 - 1.99 (m, 1H), 1.83 - 1.66 (m, 2H). Absolute stereochemistry was not determined.

Intermediate A72: rel-(2R,4aS,9bS)-7-methoxy-2-methyl-l,2,3,4,4a,9b-hexahydrofuro[2,3- b:4,5-b']dipyridine

Step 1:

[1390] A mixture of 3-bromo-2-chloro-6-methoxypyridine (25.0 g, 112.37 mmol), Pd(OAc)₂, (5.04 g, 22.47 mmol), TBAC (34.36 g, 123.61 mmol), AcOK (33.08 g, 337.122 mmol) and hex-5-en-2-one (12.14 g, 123.61 mmol) in DMF (1750 mL) was stirred at 80 °C for 16 h under nitrogen atmosphere. The reaction mixture was quenched with saturated NaHCCh (aq.) and extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered and concentrated under reduced pressure. The residue was purified by flash column chromatography with 0-10% EtOAc in PE to afford (E)-6-(2-chloro-6-methoxypyridin-3-yl)hex-5-en-2-one (13.2 g, 48%) as a yellow oil. MS ESI calculated for C12H14CINO2 [M+H]⁺, 240.07; found, 240.10.

[1391] A mixture of (E)-6-(2-chloro-6-methoxypyridin-3-yl)hex-5-en-2-one (13.2 g, 55.06 mmol) and NaBt (4.17 g, 110.14 mmol) in methanol (132 mL) was stirred at room temperature for 1 h under nitrogen atmosphere. The reaction was quenched by the addition of ice water at 0 °C and extracted with DCM. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered and concentrated under reduced pressure. The residue was purified by flash column chromatography with 0-20% EtOAc in PE to afford a 1:1 mixture of (R,E)-6-(2-chloro-6-methoxypyridin-3-yl)hex-5-en-2-ol and (S,E)-6-(2- chloro-6-methoxypyridin-3-yl)hex-5-en-2-ol (9.2 g, 69%) as a yellow oil. MS ESI calculated for C12H16CINO2 [M+H]⁺, 242.09; found, 242.10.

[1392] To a stirred solution of a 1:1 mixture of (R,E)-6-(2-chloro-6-methoxypyridin-3- yl)hex-5-en-2-ol and (S,E)-6-(2-chloro-6-methoxypyridin-3-yl)hex-5-en-2-ol (9.2 g, 38.06 mmol) in DCM (92 mL) were added Imidazole (5.18 g, 76.12 mmol) and tert- butyl(chloro)dimethylsilane (7.46 g, 49.48 mmol) at room temperature. The resulting mixture was stirred at room temperature for 1 h. The reaction mixture was quenched by water and extracted with DCM. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered and concentrated under reduced pressure. The residue was purified by flash column chromatography with 0-10% EtOAc in PE to afford a 1:1 mixture of (R,E)-3-(5-((tert-butyldimethylsilyl)oxy)hex- 1 -en- 1 -yl)-2-chloro-6-methoxypyridine and (S,E)-3-(5-((tert-butyldimethylsilyl)oxy)hex- 1 -en- 1 -yl)-2-chloro-6-methoxypyridine (13.2 g, 97%) as a yellow oil. MS ESI calculated for Ci₈H₃oClN0₂Si [M+H]⁺, 356.17; found, 356.15.

Step 4:

[1393] A mixture of a 1:1 mixture of (R,E)-3-(5-((tert-butyldimethylsilyl)oxy)hex-l-en-l- yl)-2-chloro-6-methoxypyridine and (S,E)-3-(5-((tert-butyldimethylsilyl)oxy)hex-l-en-l-yl)- 2-chloro-6-methoxypyridine (11.2 g, 31.43 mmol), sodium (tert-butoxycarbonyl)chloroamide (16.89 g, 97.44 mmol), l-[(R)-[(2R,4S,5R)-5-ethyl-l-azabicyclo[2.2.2]octan-2-yl](6- methoxyquinolin-4-yl)methoxy]-4-[(lS)-l-(pyridin-4-yl)propoxy]phthalazine ((supplier: Shanghai Accela ChemBio Co., Ltd. CAS# 140924-50-1)) (2.49 g, 3.14 mmol) and Potassium osmate(VI) dihydrate (2.32 g, 6.28 mmol) in propan-l-ol (125 mL) and H₂O (62 mL) was stirred at 0 °C for 1 h under nitrogen atmosphere. The reaction mixture was quenched with saturated NaHCO₃ (aq.) and extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered and concentrated under reduced pressure. The residue was purified by reverse phase flash column chromatography with 10% ~ 80% MeCN in Water (10 mmol/L NH4HCO3) to afford a 1:1 mixture of tert-butyl ((lR*,2R*,5R)-5-((tert-butyldimethylsilyl)oxy)-l-(2-chloro-6- methoxypyridin-3-yl)-2-hydroxyhexyl)carbamate and tert-butyl ((lR*,2R*,5S)-5-((tert- butyldimethylsilyl)oxy)-l-(2-chloro-6-methoxypyridin-3-yl)-2-hydroxyhexyl)carbamate (6.9 g, 44%) as a brown oil. MS ESI calculated for C23H4iClN2OsSi [M+H]⁺, 489.25; found, 489.30.

Step 5:

[1394] A mixture of 1:1 mixture of tert-butyl ((lR*,2R*,5R)-5-((tert- butyldimethylsilyl)oxy)- 1 -(2-chloro-6-methoxypyridin-3-yl)-2-hydroxyhexyl)carbamate and tert-butyl ((lR*,2R*,5S)-5-((tert-butyldimethylsilyl)oxy)-l-(2-chloro-6-methoxypyridin-3- yl)-2-hydroxyhexyl)carbamate (6.9 g, 14.10 mmol), Pd(OAc)2 (633 mg, 2.82 mmol), JohnPhos (1.68 g, 5.64 mmol) and CS2CO3 (13.8 g, 42.31 mmol) in toluene (75 mL) was stirred at 100 °C for 16 h under nitrogen atmosphere. The resulting mixture was concentrated under reduced pressure. The reaction mixture was quenched with water and extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered and concentrated under reduced pressure. The residue was purified by flash column chromatography with 0 ~ 20% EtOAc in PE to afford a 1 : 1 mixture of tert-butyl ((2R*,3R*)-2-((R)-3-((tert-butyldimethylsilyl)oxy)butyl)-6-methoxy-2,3-dihydrofuro[2,3- b]pyridin-3-yl)carbamate and tert-butyl ((2R*,3R*)-2-((S)-3-((tert- butyldimethylsilyl)oxy)butyl)-6-methoxy-2,3-dihydrofuro[2,3-b]pyridin-3-yl)carbamate (3.9 g, 61%) as a fight yellow oil. MS ESI calculated for C23H4oN20sSi [M+H]⁺, 453.27; found, 453.35.

Step 6:

[1395] To a mixture of a 1: 1 mixture of tert-butyl ((2R*,3R*)-2-((R)-3-((tert- butyldimethylsilyl)oxy)butyl)-6-methoxy-2,3-dihydrofuro[2,3-b]pyridin-3-yl)carbamate and tert-butyl ((2R*,3R*)-2-((S)-3-((tert-butyldimethylsilyl)oxy)butyl)-6-methoxy-2,3- dihydrofuro[2,3-b]pyridin-3-yl)carbamate (3.9 g, 8.61 mmol) in methanol (80 mL) was added hydrogen chloride (4.0 M in ethyl acetate) (39 mL). The mixture was stirred at room temperature for 0.5 h. The resulting mixture was concentrated under reduced pressure. The residue was dissolved in MeOH (80 mL), EtsN (17.44 g, 172.32 mmol) and BoczO (4.70 g, 21.54 mmol) were added to the mixture at room temperature. The resulting mixture was stirred at room temperature for 16 h. The reaction mixture was concentrated under reduced pressure. The residue was purified by flash column chromatography with 0-80% EtOAc in PE to afford a 1:1 mixture of tert-butyl ((2R*,3R*)-2-((R)-3-hydroxybutyl)-6-methoxy-2,3- dihydrofuro[2,3-b]pyridin-3-yl)carbamate and tert-butyl ((2R*,3R*)-2-((S)-3-hydroxybutyl)- 6-methoxy-2,3-dihydrofuro[2,3-b]pyridin-3-yl)carbamate (2.3 g, 79%) as a white solid. MS ESI calculated for C17H26N2O5 [M+H]⁺, 339.18; found, 339.15.

[1396] A mixture of a 1:1 mixture of tert-butyl ((2R*,3R*)-2-((R)-3-hydroxybutyl)-6- methoxy-2,3-dihydrofuro[2,3-b]pyridin-3-yl)carbamate and tert-butyl ((2R*,3R*)-2-((S)-3- hydroxybutyl)-6-methoxy-2,3-dihydrofuro[2,3-b]pyridin-3-yl)carbamate (2.3 g, 6.79 mmol) and 2-(tributyl-k⁵-phosphaneylidene)acetonitrile (CAS No. 157141-27-0) (3.28 g, 13.59 mmol) in toluene (23 mL) was stirred at 110 °C for 16 h under nitrogen atmosphere. The resulting mixture was concentrated under reduced pressure. The residue was purified by flash column chromatography with 0 - 10% EtOAc in PE to afford a 1:1 mixture of tert-butyl (2S,4aR*,9bR*)-7-methoxy-2-methyl-3,4,4a,9b-tetrahydrofuro[2,3-b:4,5-b']dipyridine- l(2H)-carboxylate and tert-butyl (2R,4aR*,9bR*)-7-methoxy-2-methyl-3,4,4a,9b- tetrahydrofuro[2,3-b:4,5-b']dipyridine-l(2H)-carboxylate (1.8 g, 82%) as a yellow oil. MS ESI calculated for C17H24N2O4 [M+H]⁺, 321.17; found, 321.15.

Step 7:

[1397] The 1:1 mixture of tert-butyl (2S,4aR*,9bR*)-7-methoxy-2-methyl-3,4,4a,9b- tetrahydrofuro[2,3-b:4,5-b']dipyridine-l(2H)-carboxylate and tert-butyl (2R,4aR*,9bR*)-7- methoxy-2-methyl-3,4,4a,9b-tetrahydrofuro[2,3-b:4,5-b']dipyridine-l(2H)-carboxylate (1.8 g) was separated by Prep-chiral SFC with the following conditions: [Column: CHIRALPAK IG, 5*25 cm, 10 pm; Mobile Phase A: CO₂, Mobile Phase B: MEOH: MTBE=1: 1 (0.1% 2M NH3M); Flow rate: 100 mL/min; Gradient (B%): isocratic 20% B; RTl(min): 7; RT2(min): 9; Sample Solvent: MEOH] to afford fraction A with retention time at 7 minute. The fraction A was further separated by Prep-chiral SFC with the following conditions: [Column: CHIRAL ART Cellulose-SC, 3*25 cm, 5 pm; Mobile Phase A: CO2, Mobile Phase B: MEOH; Flow rate: 80 mL/min; Gradient (B%): isocratic 15% B; RTl(min): 4.2; RT2(min): 5.5; Sample Solvent: MEOH] to afford rel-tert-butyl (2R,4aS,9bS)-7-methoxy-2-methyl- 3,4,4a,9b-tetrahydrofuro[2,3-b:4,5-b']dipyridine-l(2H)-carboxylate isomer 1 (500 mg) as a light yellow solid with retention time at 5.5 minute.

[1398] The first chiral resolution also afford rel-tert-butyl (2R,4aS,9bS)-7-methoxy-2- methyl-3,4,4a,9b-tetrahydrofuro[2,3-b:4,5-b']dipyridine-l(2H)-carboxylate isomer 2 (800 mg) as a light yellow solid with retention time at 9 minute.

[1399] rel-tert-butyl (2R,4aS,9bS)-7-methoxy-2-methyl-3,4,4a,9b-tetrahydrofuro[2,3-b:4,5- b']dipyridine-l(2H)-carboxylate isomer 1: MS ESI calculated for C17H24N2O4 [M+H]⁺, 321.17; found, 321.15. 'H NMR (400 MHz, DMSO-d₆) 8 (ppm) 7.43 (d, J = 8.0 Hz, 1H), 6.32 (d, J = 8.0 Hz, 1H), 5.87 (d, J= 10.4 Hz, 1H), 5.18 - 5.12 (m, 1H), 3.96 - 3.86 (m, 1H), 3.79 (s, 3H), 1.90 - 1.74 (m, 2H), 1.70 - 1.56 (m, 1H), 1.47 (s, 9H), 1.21 - 1.06 (m, 1H), 0.81 (d, J = 6.4 Hz, 3H). Absolute stereochemistry was not determined.

[1400] rel-tert-butyl (2R,4aS,9bS)-7-methoxy-2-methyl-3,4,4a,9b-tetrahydrofuro[2,3-b:4,5- b']dipyridine-l(2H)-carboxylate isomer 2: MS ESI calculated for C17H24N2O4 [M+l]⁺, 321.17; found, 321.15. *H NMR (400 MHz, DMSO-d₆) 8 (ppm) 7.76 (d, J = 8.0 Hz, 1H), 6.29 (d, J = 8.0 Hz, 1H), 5.30 - 5.18 (m, 1H), 5.02 - 4.96 (m, 1H), 3.87 - 3.75 (m, 4H), 2.05 - 1.86 (m, 2H), 1.77 - 1.66 (m, 1H), 1.51 - 1.40 (m, 10H), 1.20 (d, J = 6.4 Hz, 3H).

Absolute stereochemistry was not determined.

Step 8:

[1401] To a mixture of rel-tert-butyl (2R,4aS,9bS)-7-methoxy-2-methyl-3,4,4a,9b- tetrahydrofuro[2,3-b:4,5-b']dipyridine-l(2H)-carboxylate isomer 1 (500 mg, 1.56 mmol) in ethyl acetate (5 mL) was added hydrogen chloride (4.0 M in ethyl acetate) (5 mL) was stirred at room temperature for 16 h. The resulting mixture was concentrated under reduced pressure to afford rel-(2R,4aS,9bS)-7-methoxy-2-methyl-l,2,3,4,4a,9b-hexahydrofuro[2,3-b:4,5- b']dipyridine hydrochloride (A72) (450 mg, crude) as a yellow semi-solid. MS ESI calculated for C12H16N2O2 [M+H]⁺, 221.12; found, 221.10. 'H NMR (400 MHz, DMSCM₆) 8 (ppm) 10.37 (br, 1H), 7.98 (br, 1H), 7.84 (d, J = 8.0 Hz, 1H), 6.49 (d, J = 8.0 Hz, 1H), 4.85 - 4.68 (m, 2H), 3.83 (s, 3H), 3.26 - 3.10 (m, 1H), 2.13 - 1.97 (m, 2H), 1.81 - 1.71 (m, 1H), 1.59 - 1.48 (m, 1H), 1.22 (d, J = 6.4 Hz, 3H). Relative stereochemistry was determined by NOESY. Absolute stereochemistry was not determined.

Intermediate A73 isomer 1: rel-(5aR,8R,9aR)-3-methoxy-8-methyl-5a,6,7,8,9,9a- hexahydropyrido[2',3':4,5]furo[2,3-b]pyrazine isomer 1

Isomer 1

Intermediate A73 isomer 2: rel-(5aR,8R,9aR)-3-methoxy-8-methyl-5a,6,7,8,9,9a- hexahydropyrido[2',3':4,5]furo[2,3-b]pyrazine isomer 2

Isomer 2

Intermediate A73 isomer 3: rel-(5aR,8R,9aR)-3-methoxy-8-methyl-5a,6,7,8,9,9a- hexahydropyrido[2',3^,:4,5]furo[2,3-b]pyrazine isomer 3 and,

Intermediate A73 isomer 4: rel-(5aR,8R,9aR)-3-methoxy-8-methyl-5a,6,7,8,9,9a- hexahydropyrido[2',3':4,5]furo[2,3-b]pyrazine isomer 4

Step-1:

[1402] To a stirred solution of 5-bromo-6-chloropyrazin-2-amine (350.0 g, 1679.14 mmol) in H2SO4 (875 mL) was added a solution of Sodium nitrite (129.8 g, 1880.63 mmol) in water (100 mL) dropwise at 0 °C. The resulting solution was then stirred at 0 °C for 1 h. The reaction was quenched by ice water. The precipitated solids were collected by filtration and washed with water to afford 5-bromo-6-chloropyrazin-2-ol (302.2 g, 85%) as a yellow solid. MS ESI calculated for C₄H₂BrClN2O [M-l]’, 206.90/208.90; found, 206.85/208.85.

Step-2:

[1403] To a stirred solution of 5-bromo-6-chloropyrazin-2-ol (300.0 g, 1432.46 mmol), methanol (91.8 g, 2864.92 mmol), PPh₃ (751.5 g, 2864.92 mmol) in THF (3000 mL) was added DIAD (579.3 g, 2864.92 mmol) dropwise at 0 °C under nitrogen atmosphere. The mixture was stirred at 20 °C for 2 h. The resulting mixture was concentrated under vacuum. The residue was diluted and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous Na2SO₄. The resulting mixture was concentrated under reduced pressure. The residue was purified by flash column chromatography with 0 ~ 20% petroleum ether in ethyl acetate to afford 2-bromo-3-chloro-5-methoxypyrazine (201.1 g, 62%) as a white solid. MS ESI calculated for C₅H₄BrClN₂O [M+H]⁺, 222.92/224.92; found, 222.90/224.85.

[1404] A mixture of 2-bromo-3-chloro-5-methoxypyrazine (200.1 g, 895.05 mmol), 1- hexen-5-one (175.7 g, 1790.11 mmol), Pd(OAc)₂ (10.0 g, 44.75 mmol), AcOK (87.8 g, 895.05 mmol) and tetrabutyl(chloro)amine (746.3 g, 2685.16 mmol) in DMF (3000 mL) was stirred at 80 °C for 2 h under nitrogen atmosphere. The resulting mixture was filtered, the filter cake was washed with ethyl acetate. The filtrate was quenched with water. The aqueous layer was extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous Na2SO₄. The resulting mixture was concentrated under reduced pressure. The residue was purified by flash column chromatography with 0 ~ 20% petroleum ether in ethyl acetate to afford (E)-6-(3-chloro-5-methoxypyrazin-2-yl)hex-5-en-2-one (37.2 g, 17 %) as a brown oil. MS ESI calculated for C11H13CIN2O2 [M+H]⁺, 241 .07; found,

241.00.

Step-4:

[1405] To a stirred solution of tert-butyl carbamate (54.3 g, 463.66 mmol) in propan-l-ol (730 mL) was slowly added NaOH (aq. 0.4 M) (730 mL), the mixture was stirred at 0 °C for 15 min. Then l,3-dichloro-5,5-dimethylimidazolidine-2, 4-dione (45.7 g, 231.83 mmol) was added. The resulting mixture was stirred at 0 °C for additional 30 min. This was followed by the addition of a solution of (DHQ)2-PHAL (supplier: Shanghai Accela ChemBio Co., Ltd. CAS# 140924-50-1) (12.0 g, 15.45 mmol) in propan-l-ol (154 mL), after stirring at 0 °C for 20 min., (E)-6-(3-chloro-5-methoxypyrazin-2-yl)hex-5-en-2-one (37.2 g, 154.55 mmol) and K2OSO42H2O (5.7 g, 15.45 mmol) were sequentially added at 0 °C. The resulting mixture was stirred at room temperature for 16 h. The reaction mixture was extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered and concentrated under vacuum. The mixture was purified by reverse phase flash column chromatography with 5-50% acetonitrile in water to afford rel-tert-butyl ((lS,2S)-l-(3-chloro-5-methoxypyrazin-2-yl)-2-hydroxy-5-oxohexyl)carbamate (5.1 g, 8%) as a yellow oil. MS ESI calculated for C16H24CIN3O5 [M+H]⁺, 374.14; found, 374.05.

Step-5:

[1406] To a stirred solution of rel-tert-butyl ((lS,2S)-l-(3-chloro-5-methoxypyrazin-2-yl)- 2-hydroxy-5-oxohexyl)carbamate (5.1 g, 13.64 mmol) and CS2CO3 (1.8 g, 5.45 mmol) in toluene (100 mL) were added JohnPhos (3.3 g, 10.91 mmol) and Pd(OAc)2 (9.2 g, 40.92 mmol). The resulting mixture was stirred at 100 °C for 12 h under nitrogen atmosphere. The resulting mixture was filtered, the filter cake was washed with ethyl acetate. The filtrate was concentrated under reduced pressure. The mixture was quenched with water. The aqueous layer was extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous Na2SO4. The resulting mixture was concentrated under reduced pressure. The mixture was purified by reverse flash chromatography with 5-30% acetonitrile in water to afford rel-tert-butyl ((6S,7S)-3-methoxy-6-(3-oxobutyl)-6,7-dihydrofuro[2,3- b]pyrazin-7-yl)carbamate (1.2 g, 26%) as a white solid. MS ESI calculated for C16H23N3O5 [M+H]⁺, 338.16 found, 338.10.

Step-6:

[1407] To a stirred solution rel-tert-butyl ((6S,7S)-3-methoxy-6-(3-oxobutyl)-6,7- dihydrofuro[2,3-b]pyrazin-7-yl)carbamate (1.1 g, 3.26 mmol) in methanol (20mL) was added NaBFU (0.4 g, 9.78 mmol) at 0 °C. The resulting mixture was stirred at room temperature for 1 h. The residue was quenched by ice water and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered and concentrated under vacuum. The residue was purified by flash chromatography with 0 ~ 80% petroleum ether in ethyl acetate to afford a 1:1 mixture of tert-butyl ((6R*,7R*)-6-((R)-3- hydroxybutyl)-3-methoxy-6,7-dihydrofuro[2,3-b]pyrazin-7-yl)carbamate and tert-butyl ((6R*,7R*)-6-((S)-3-hydroxybutyl)-3-methoxy-6,7-dihydrofuro[2,3-b]pyrazin-7- yl)carbamate (0.8 g, 71%) as a yellow oil. MS ESI calculated for C16H25N3O5 [M+H]⁺,

340.18; found, 340.15.

Step-7:

[1408] To a stirred solution of 1: 1 mixture of tert-butyl ((6R*,7R*)-6-((R)-3- hydroxybutyl)-3-methoxy-6,7-dihydrofuro[2,3-b]pyrazin-7-yl)carbamate and tert-butyl ((6R*,7R*)-6-((S)-3-hydroxybutyl)-3-methoxy-6,7-dihydrofuro[2,3-b]pyrazin-7- yl)carbamate (750 mg, 2.21 mmol) in toluene (15 mL) was added 2-(tributyl-X⁵- phosphaneylidene)acetonitrile (CAS No. 157141-27-0) (1066 mg, 4.42 mmol). The resulting mixture was stirred at 100 °C for 5 h. The resulting mixture was concentrated under vacuum. The crude was purified by reverse phase flash column chromatography with 5 ~ 60% acetonitrile in water to afford a 1:1 mixture of tert-butyl (5aR*,8R,9aR*)-3-methoxy-8- methyl-5a,7,8,9a-tetrahydropyrido[2',3':4,5]furo[2,3-b]pyrazine-9(6H)-carboxylate and tertbutyl (5aR*,8S,9aR*)-3-methoxy-8-methyl-5a,7,8,9a-tetrahydropyrido[2',3':4,5]furo[2,3- b]pyrazine-9(6H)-carboxylate (430 mg, 61%) as a yellow oil. MS ESI calculated for C16H23N3O4 [M+H]⁺, 322.17; found, 322.10.

Step-8:

[1409] A mixture of 1:1 mixture of tert-butyl (5aR*,8R,9aR*)-3-methoxy-8-methyl- 5a,7,8,9a-tetrahydropyrido[2',3':4,5]furo[2,3-b]pyrazine-9(6H)-carboxylate and tert-butyl (5aR*,8S,9aR*)-3-methoxy-8-methyl-5a,7,8,9a-tetrahydropyrido[2',3':4,5]furo[2,3- b]pyrazine-9(6H)-carboxylate (430 mg, 1.34 mmol) and HC1 in dioxane (4 mL, 4M) was stirred at 20 °C for 1 h. The resulting mixture was concentrated under reduced pressure. The residue was separated by Prep- Achiral SFC with the following conditions: [Column: GreenSep Basic 3*15 cm, 5 pm; Mobile Phase A: CO2, Mobile Phase B: MEOH(1% 2M NH3-MEOH); Flow rate: 75 mL/min; Gradient (B%): isocratic 12% B; Column Temperature (°C): 35; Back Pressure(bar): 100; Wave Length: 220 nm; RTl(min): 1.85; RT2(min): 2.75; Sample Solvent: MEOH] to afford fraction A (110 mg, 31%) with retention time at 1.85 minute and fraction B (95 mg, 27%) with retention time at 2.75 minute [1410] The fraction A was separated by Prep-Chiral HPLC with the following conditions: [Column: CHIRAL ART Amylose-SC 2*25 cm, 5 pm; Mobile Phase A: Hex (0.5% 2M NH3- MeOH), Mobile Phase B: MEOH: DCM=1: 1— HPLC; Flow rate: 20 mL/min; Gradient (B%): 10% B to 10% B in 20 min; Wave Length: 220/254 nm; RTl(min): 7.813; RT2(min): 14.583; Sample Solvent: MeOH: EtOH=l: 1— HPLC] to afford rel-(5aR,8R,9aR)-3-methoxy- 8-methyl-5a,6,7,8,9,9a-hexahydropyrido[2^,,3':4,5]furo[2,3-b]pyrazine isomer 1 (A73 isomer 1) (31 mg, 28%) with retention time at 7.813 minute and rel-(5aR,8R,9aR)-3-methoxy-8- methyl-5a,6,7,8,9,9a-hexahydropyrido[2',3':4,5]furo[2,3-b]pyrazine isomer 2 (A73 isomer 2) (30 mg, 27%) with retention time at 14.583 minute. Relative stereochemistry in Isomer 1 and isomer 2 were determined by NOESY. Absolute stereochemistry was not determined.

[1411] The fraction B was separated by Prep-Chiral HPLC with the following conditions: [Column: CHIRALPAK IG, 2*25 cm, 5 pm; Mobile Phase A: Hex(0.5% 2M NH₃-MeOH)- HPLC, Mobile Phase B: MeOH: DCM=1: 1— HPLC; Flow rate: 20 mL/min; Gradient (B%): 15% B to 15% B in 11.5 min; Wave Length: 220/254 nm; RTl(min): 7.85; RT2(min): 9.51; Sample Solvent: MeOH: DCM=1: 1— HPLC] to afford rel-(5aR,8S,9aR)-3-methoxy-8- methyl-5a,6,7,8,9,9a-hexahydropyrido[2',3':4,5]furo[2,3-b]pyrazine isomer 3 (A73 isomer 3) (22 mg, 22%) with retention time at 7.85 minute and rel-(5aR,8S,9aR)-3-methoxy-8-methyl- 5a,6,7,8,9,9a-hexahydropyrido[2',3':4,5]furo[2,3-b]pyrazine isomer 4 (A73 isomer 4) (32 mg, 34%) with retention time at 9.51 minute. Relative stereochemistry in Isomer 3 and isomer 4 were determined by NOESY. Absolute stereochemistry was not determined.

[1412] rel-(5aR,8R,9aR)-3-methoxy-8-methyl-5a,6,7,8,9,9a- hexahydropyrido[2',3':4,5]furo[2,3-b]pyrazine isomer 1 (A73 isomer 1): MS ESI calculated for C11H15N3O2 [M+H]⁺, 222.12; found, 222.10. 'H NMR (400 MHz, DMSO-</₆) 8 7.73 (s, 1H), 4.93 - 4.89 (m, 1H), 4.50 (d, J = 7.8 Hz, 1H), 3.84 (s, 3H), 2.61 - 2.54 (m, 1H), 2.10 - 2.00 (m, 1H), 1.78 - 1.65 (m, 1H), 1.63 - 1.56 (m, 1H), 1.14 - 1.06 (m, 1H), 0.99 (d, J= 6.4 Hz, 3H). Absolute stereochemistry was not determined.

[1413] rel-(5aR,8R,9aR)-3-methoxy-8-methyl-5a,6,7,8,9,9a- hexahydropyrido[2',3':4,5]furo[2,3-b]pyrazine isomer 2 (A73 isomer 2): MS ESI calculated for C11H15N3O2 [M+H]⁺, 222.12; found, 222.10. ’H NMR (400 MHz, DMSO-d₆) 8 7.73 (s, 1H), 4.93 - 4.89 (m, 1H), 4.50 (d, J = 7.8 Hz, 1H), 3.84 (s, 3H), 2.61 - 2.54 (m, 1H), 2.10 - 2.00 (m, 1H), 1.78 - 1.65 (m, 1H), 1.63 - 1.56 (m, 1H), 1.14 - 1.06 (m, 1H), 0.99 (d, J= 6.4 Hz, 3H). Absolute stereochemistry was not determined. [1414] rel-(5aR,8S,9aR)-3-methoxy-8-methyl-5a,6,7,8,9,9a- hexahydropyrido[2',3':4,5]furo[2,3-b]pyrazine isomer 3 (A73 isomer 3): MS ESI calculated for C11H15N3O2 [M+H]⁺, 222.12; found, 222.10. 'H NMR (400 MHz, DMSO- ₆) 3 7.69 (s, 1H), 4.64 - 4.58 (m, 1H), 4.12 (d, J = 4.8 Hz, 1H), 3.85 (s, 3H), 2.63 - 2.59 (m, 1H), 2.23 - 2.18 (m, 1H), 2.02 - 1.82 (m, 1H), 1.54 - 1.48 (m, 1H), 1.16 - 1.11 (m, 1H), 0.94 (d, J= 6.3 Hz, 3H). Absolute stereochemistry was not determined.

[1415] rel-(5aR,8S,9aR)-3-methoxy-8-methyl-5a,6,7,8,9,9a- hexahydropyrido[2',3':4,5]furo[2,3-b]pyrazine isomer 4 (A73 isomer 4): MS ESI calculated for C11H15N3O2 [M+H]⁺, 222.12; found, 222.10. 'H NMR (400 MHz, DMSO-</₆) 8 7.69 (s, 1H), 4.64 - 4.58 (m, 1H), 4.12 (d, J = 4.8 Hz, 1H), 3.85 (s, 3H), 2.63 - 2.59 (m, 1H), 2.23 - 2.18 (m, 1H), 2.02 - 1.82 (m, 1H), 1.54 - 1.48 (m, 1H), 1.16 - 1.11 (m, 1H), 0.94 (d, J= 6.3 Hz, 3H). Absolute stereochemistry was not determined.

Intermediate A74: rel-(4aR,10bR)-8-cyclopropoxy-2,3,4,4a,6,10b-hexahydro-lH- pyrano[3,2-b:5,4-b']dipyridine

Step-1:

[1416] To a stirred mixture of rel-tert-butyl (4aR, 10bR)-8-chloro-2,3,4,4a,6, 1 Ob- hexahydro-lH-pyrano[3,2-b:5,4-b']dipyridine-l-carboxylate (from A40) (600 mg, 1.84 mmol) and cyclopropanol (321 mg, 5.54 mmol) in Dioxane (10 mL) were added CS2CO3 (2.41 g, 7.38 mmol), l',3',5'-triphenyl-5-{[(lr,3R,5S,7s)-adamantan-l-yl][(3R,5S,7s)- adamantan-l-yl]phosphanyl}-l'H-l,4'-bipyrazole (183 mg, 0.27 mmol) and Pd2(dba)3-CHCh (286 mg, 0.27 mmol) at room temperature under nitrogen atmosphere. The resulting mixture was stirred at 110 °C for 16 h under nitrogen atmosphere. The resulting mixture was filtered, the filter cake was washed with Dioxane (10 mL). The filtrate was concentrated under reduced pressure. The residue was purified by reversed-phase flash column chromatography with 40% to 70% MeCN in Water to afford rel-tert-butyl (4aR,10bR)-8-cyclopropoxy- 2,3,4,4a,6,10b-hexahydro-lH-pyrano[3,2-b:5,4-b']dipyridine-l-carboxylate (120 mg, 18% yield) as a colorless oil. MS ESI calculated for C19H26N2O4 [M+H]⁺, 347.19; found, 347.10.

Step-2:

[1417] A mixture of rel-tert-butyl (4aR,10bR)-8-cyclopropoxy-2,3,4,4a,6,10b-hexahydro- lH-pyrano[3,2-b:5,4-b']dipyridine-l-carboxylate (55 mg, 0.15 mmol) and HC1 in 1,4-dioxane (4.0 M) (1 mL) was stirred at room temperature for 0.5 h. The resulting mixture was concentrated under vacuum to afford rel-(4aR,10bR)-8-cyclopropoxy-2,3,4,4a,6,10b- hexahydro-lH-pyrano[3,2-b:5,4-b']dipyridine hydrochloride (A74) (50 mg, crude) as a white solid. MS ESI calculated for C14H18N2O2 [M+H]⁺, 247.14; found, 247.10.

[1418] The absolute stereochemistry of A74 was determined as S, S-configuration, prepared from A40, the absolute stereochemistry of which was confirmed. Accordingly, A74 is represented by the structure:

Intermediate A75: rel-(4aS,9bS)-7-isopropyl-l,2,3,4,4a,9b-hexahydrofuro[2,3-b:4,5- b']dipyridine

Step-1

[1419] A mixture of rel-tert-butyl (4aS,9bS)-7-chloro-3,4,4a,9b-tetrahydrofuro[2,3-b:4,5- b']dipyridine-l(2H)-carboxylate (180 mg, 0.58 mmol), 4,4,5,5-tetramethyl-2-(prop-l-en-2- yl)-l,3,2-dioxaborolane (197 mg, 1.17 mmol), Pd(dppf)Ch-CH2C12 (42 mg, 0.05 mmol) and K2CO3 (152 mg, 1.10 mmol) in Dioxane (2 mL) and H2O (0.5 mL) was stirred at 80 °C for 16 h under nitrogen atmosphere. The reaction mixture was quenched with water and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under vacuum. The residue was purified by normal phase flash chromatography with a 25 g silica gel column eluted with 0-30% ethyl acetate in petroleum ether to afford rel-tert-butyl (4aS,9bS)-7-(prop-l-en-2-yl)-3,4,4a,9b- tetrahydrofuro[2,3-b:4,5-b']dipyridine-l(2H)-carboxylate (130 mg, 71%) as a white solid. MS ESI calculated for C18H24N2O3 [M+H]⁺, 317.18; found, 317.15.

Step-2:

[1420] To a solution of rel-tert-butyl (4aS,9bS)-7-(prop-l-en-2-yl)-3,4,4a,9b- tetrahydrofuro[2,3-b:4,5-b']dipyridine-l(2H)-carboxylate (130 mg, 0.41 mmol) in methanol (5 mL) was added Pd/C (10% active on carbon) (130 mg) at room temperature. The mixture was degassed via vacuum evacuation, then backfilled with hydrogen, and this process was repeated three times. The reaction mixture was stirred at room temperature for 16 h under hydrogen atmosphere. The mixture was filtered through a Celite pad. The filtrate was collected and concentrated under vacuum to afford to afford rel-tert-butyl (4aS,9bS)-7- isopropyl-3,4,4a,9b-tetrahydrofuro[2,3-b:4,5-b']dipyridine-l(2H)-carboxylate (160 mg, crude) as a white solid. MS ESI calculated for C18H26N2O3 [M+H]⁺, 319.19; found, 319.15.

Step-3:

[1421] To a mixture of rel-tert-butyl (4aS,9bS)-7-isopropyl-3,4,4a,9b-tetrahydrofuro[2,3- b:4,5-b']dipyridine-l(2H)-carboxylate (160 mg, 0.50 mmol) in Dioxane (1 mL) was added HC1 (4M in 1,4-dioxane) (3 mL) at room temperature. The resulting mixture was stirred at room temperature for 1 h. The solvents were removed under vacuum to afford rel-(4aS,9bS)- 7-isopropyl-l,2,3,4,4a,9b-hexahydrofuro[2,3-b:4,5-b']dipyridine hydrochloride (A75) (190 mg) as a white solid, which was used in the next step without further purification. MS ESI calculated for C13H18N2O [M+H]⁺, 219.15; found, 219.15. 'H NMR (400 MHz, DMSO) 5 10.44 (s, 1H), 8.54 (s, 1H), 7.88 (d, J = 7.6 Hz, 1H), 6.97 (d, J = 7.6 Hz, 1H), 4.84 - 4.72 (m, 2H), 3.25 - 3.03 (m, 1H), 2.96 - 2.77 (m, 1H), 2.26 - 2.17 (m, 1H), 2.12 - 1.94 (m, 1H), 1.80 - 1.64 (m, 3H), 1.21 (d, J = 6.8 Hz, 6H). Absolute stereochemistry was not determined.

Intermediate A76: rel-(5aR,l lbS)-9-(difluoromethoxy)-2,3,5,5a,7,l Ib-hexahydro-lH- isochromeno [4,3-e] [ 1 ,4] oxazepine

A76

Step-1:

[1422] To a stirred mixture of 2-((tert-butyldimethylsilyl)oxy)ethan-l-ol (50.00 g, 143.96 mmol) in THF (500 mL) was added NaH (60% in mineral oil) (5.18 g, 129.5 mmol) in portions at 0 °C. After stirring at 0 °C for 1 h, 3-bromoprop- 1-yne (40.58 g, 215.95 mmol) was added dropwsie at 0 °C. The resulting mixture was stirred at 50 °C for additional 16 h. The reaction was quenched with water at 0 °C. The resulting mixture was extracted with ethyl acetate. The combined organic layers were dried over anhydrous NazSC . After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by flash column chromatography with 0-20% DCM in PE to afford tert-butyldimethyl(2-(prop-2-yn-l- yloxy)ethoxy)silane (49.40 g, 80%) as a yellow oil. MS ESI calculated for Ci 1H22O2S1 [M+H]⁺,215.14; found, 215.13.

Step-2:

[1423] To a mixture of tert-butyldimethyl(2-(prop-2-yn-l-yloxy)ethoxy)silane (49.40 g, 230.43 mmol), 4,4,5,5-tetramethyl-l,3,2-dioxaborolane (30.97 g, 241.95 mmol) and Et₃N (2.33 g, 23.04 mmol) was added bis(cyclopenta-l,3-dien-l-yl)zirconiumbis(ylium) chloride hydride (5.92 g, 23.04 mmol) at room temperature. The resulting mixture was stirred at 60 °C for 16 h under nitrogen atmosphere. The reaction mixture was treated with PE (100 mL), then the mixture was filtered, the filter cake was washed with PE. The filtrate was concentrated under reduced pressure. The residue was purified by flash column chromatography with 0- 50% DCM in PE to afford (E)-tert-butyldimethyl(2-((3-(4,4,5,5-tetramethyl-l,3,2- dioxaborolan-2-yl)allyl)oxy)ethoxy)silane (24.51 g, 31%) as a yellow oil. MS ESI calculated for Ci₇H₃5BO₄Si [M+H]⁺, 343.24; found, 343.23.

Step-3: [1424] To a stirred mixture of (E)-tert-butyldimethyl(2-((3-(4,4,5,5-tetramethyl-l,3,2- dioxaborolan-2-yl)allyl)oxy)ethoxy)silane (24.50 g, 71.56 mmol) and K2CO3 (29.67 g, 214.69 mmol) in dioxane (140 mL) and H2O (14 mL) was added Pd(dppf)Ch (5.24 g, 7.16 mmol) at room temperature under nitrogen atmosphere. The resulting mixture was stirred at 100 °C for 1 h. The resulting mixture was filtered, the filter cake was washed with ethyl acetate. The filtrate was concentrated under reduced pressure. The residue was purified by flash column chromatography with 0-50% DCM in PE to afford methyl (E)-2-(3-(2-((tert- butyldimethylsilyl)oxy)ethoxy)prop-l-en-l-yl)-5-(difluoromethoxy)benzoate (24.80 g, 83%) as a yellow oil. MS ESI calculated for C2oH3oF20sSi [M+H]⁺, 417.18; found, 417.17.

Step-4:

[1425] To a stirred mixture of tert-butyl carbamate (9.20 g, 78.50 mmol) in propan- l-ol (178 mL) were added a solution of NaOH (2.83 g, 70.65 mmol) in H2O (178 mL) at room temperature. After stirring at room temperature for 5 minutes, DCDMH (7.73 g, 39.25 mmol) was added at 0 °C. The resulting mixture was stirred at 0 °C for additional 30 minutes, this was followed by the addition of (DHQ)2PHAL (supplier: Shanghai Accela ChemBio Co., Ltd. CAS# 140924-50-1) (2.04 g, 2.61 mmol), Potassium osmate(VI) dihydrate (0.96 g, 2.61 mmol) and methyl (E)-2-(3-(2-((tert-butyldimethylsilyl)oxy)ethoxy)prop-l-en-l-yl)-5- (difluoromethoxy)benzoate (10.9 g, 26.16 mmol) at 0 °C. The resulting mixture was stirred at room temperature for additional 16 h. The reaction mixture was quenched with water and extracted with EtOAc. The combined organic layers were dried over anhydrous Na2SC>4. After filtration, the filtrate was concentrated under reduced pressure.

[1426] The residue was dissolved in DCM (100 mL), then DCC (10.80 g, 52.33 mmol) and DMAP (643 mg, 5.22 mmol) were added at room temperature. The resulting mixture was stirred at room temperature for additional 2 h. The resulting mixture was concentrated under vacuum. The residue was purified by silica gel column chromatography, eluted with PE / EtOAc (1:3) to afford rel-tert-butyl ((3R,4S)-3-((2-((tert- butyldimethylsilyl)oxy)ethoxy)methyl)-7-(difluoromethoxy)-l-oxoisochroman-4- yl)carbamate (10.5 g, 77% yield) as a yellow oil. MS ESI calculated for C₂4H37F₂NO?Si [M+H]⁺, 518.23; found, 518.24.

Step-5:

[1427] To a stirred mixture of rel-tert-butyl ((3R,4S)-3-((2-((tert- butyldimethylsilyl)oxy)ethoxy)methyl)-7-(difluoromethoxy)-l-oxoisochroman-4- yl)carbamate (23.60 g, 45.59 mmol) in THF (240 mL) were added NaBFU (5.17 g, 136.77 mmol) at 0 °C. The reaction was stirred at room temperature for 16 h. The reaction was quenched by the addition of water at 0 °C. The mixture was extracted with ethyl acetate. The combined organic layers were dried over anhydrous Na₂SC>4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by flash column chromatography with 0-50% ethyl acetate in petroleum ether to afford rel-tert-butyl (( lR,2S)-3-(2-((tert-butyldimethylsilyl)oxy)ethoxy)- 1 -(4-(difluoromethoxy)-2- (hydroxymethyl)phenyl)-2-hydroxypropyl)carbamate (17.93 g, 75%) as a colorless oil. MS ESI calculated for (C₂4H₄iF₂NO7Si) [M+H]⁺, 522.26; found, 522.25.

Step-6:

[1428] A solution of rel-tert-butyl ((lR,2S)-3-(2-((tert-butyldimethylsilyl)oxy)ethoxy)-l- (4-(difluoromethoxy)-2-(hydroxymethyl)phenyl)-2-hydroxypropyl)carbamate (17.80 g, 34.25 mmol) and 2-(tributylA⁵-phosphaneylidene)acetonitrile (CAS No. 157141-27-0) (16.53 g, 68.50 mmol) in toluene (180 mL) was stirred at 110 °C for 16 h under nitrogen atmosphere. The resulting mixture was concentrated under vacuum. The residue was purified by flash column chromatography with 0-50% ethyl acetate in petroleum ether to afford rel-tert-butyl ((3R,4S)-3-((2-((tert-butyldimethylsilyl)oxy)ethoxy)methyl)-7- (difluoromethoxy)isochroman-4-yl)carbamate (10.84 g, 62%) as a brown oil. MS ESI calculated for C24H39F₂NO₆Si [M+H]⁺, 504.25; found, 504.24.

Step-7:

[1429] To a mixture of rel-tert-butyl ((3R,4S)-3-((2-((tert- butyldimethylsilyl)oxy)ethoxy)methyl)-7-(difluoromethoxy)isochroman-4-yl)carbamate (10.70 g, 20.59 mmol) in THF (110 mL) was added TBAF (10.77 g, 41.18 mmol). The mixture was stirred at room temperature for 16 h. The reaction was quenched by water and extracted with ethyl acetate. The combined organic layers were washed with water, dried over anhydrous NaiSC . After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by flash column chromatography with 0-50% ethyl acetate in petroleum ether to afford rel-tert-butyl ((3R,4S)-7-(difluoromethoxy)-3-((2- hydroxyethoxy)methyl)isochroman-4-yl)carbamate (6.53 g, 81%) as a yellow solid. MS ESI calculated for C18H25F2NO6 [M+H]⁺, 390.16; found, 390.15

Step-8:

[1430] To a stirred mixture of rel-tert-butyl ((3R,4S)-7-(difluoromethoxy)-3-((2- hydroxyethoxy)methyl)isochroman-4-yl)carbamate (4.40 g, 8.47 mmol) and TEA (4.28 g, 42.33 mmol) in DCM (45 mL) was added methanesulfonyl methanesulfonate (5.90 g, 33.86 mmol) at 0 °C. The resulting mixture was stirred at room temperature for 1 h. The reaction was quenched by the addition of NaHCCh (sat.) at 0 °C. The resulting mixture was extracted with DCM. The combined organic layers were dried over anhydrous Na2SC>4. After filtration, the filtrate was concentrated under reduced pressure. The residue was dissolved in DCM (45 mL), then TFA (15 mL) was added at room temperature. The resulting mixture was stirred at room temperature for additional 30 min. The reaction mixture was concentrated under vacuum. The residue was dissolved in acetonitrile (80 mL), then 1, 2, 2,6,6- pentamethylpiperidine (3.94 g, 25.39 mmol) was added at room temperature. The resulting mixture was stirred at 80 °C for additional 16 h. The mixture was concentrated under vacuum. The residue was purified by reverse phase flash column chromatography with 10- 40% acetonitrile in water to afford rel-(5aR,l lbS)-9-(difhioromethoxy)-2,3,5,5a,7,l lb- hexahydro-lH-isochromeno[4,3-e][l,4]oxazepane (A76) (1.20 g, 36%) as a yellow oil. MS ESI calculated for C13H15F2NO3 [M+H]⁺, 272.10; found, 272.05. ^XH NMR (400 MHz, DMSO-d₆) 6 7.46 (d, J= 8.4 Hz, 1H), 7.36 - 6.92 (m, 2H), 6.87 (d, J = 2.4 Hz, 1H), 4.75 - 4.50 (m, 2H), 4.15 - 4.10 (m, 1H), 3.92 - 3.80 (m, 2H), 3.64 (d, J = 3.6 Hz, 1H), 3.53 - 3.52 (m, 1H), 3.49 (d, J = 7.8 Hz, 1H), 3.45 - 3.39 (m, 1H), 3.05 - 2.87 (m, 2H). Absolute stereochemistry was not determined.

Intermediate A77: rel-(2R,4aS,9bS)-7-isopropyl-2-methyl-l,2,3,4,4a,9b-hexahydrofuro[2,3- b:4,5-b']dipyridine

A77

Step-1:

[1431] To a stirred solution of 2,6-dichloro-3-iodopyridine (10.0 g, 36.51 mmol) and hex- 5-en-2-one (3.94 g, 40.16 mmol) in DMF (100 mL) were added AcOK (10.75 g, 109.53 mmol), tetrabutylazanium chloride (11.16 g, 40.16 mmol) and Pd(OAc)2 (1.64 g, 7.30 mmol) at room temperature. The resulting mixture was stirred at 80 °C for 2 h under nitrogen atmosphere. The mixture was allowed to cool down to room temperature and then quenched with water. The mixture was extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SC>4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-20% ethyl acetate in petroleum ether to afford (E)-6-(2,6- dichloropyridin-3-yl)hex-5-en-2-one (3.46 g, 38%) as a yellow oil. MS ESI calculated for C11H11CI2NO [M+H]⁺, 244.02; found, 244.00.

Step-2:

[1432] To a stirred solution of tert-butyl carbamate (20.83 g, 177.78 mmol) in propan-l-ol (445 mL) was added a solution of NaOH (6.19 g, 154.84 mmol) in H2O (387 mL) at room temperature. The mixture was stirred at room temperature for 10 min., then DCDMH (16.95 g, 86.02 mmol) was added at room temperature. After stirring at room temperature for 30 min., this was followed by the addition of a solution of (DHQ)2PHAL (supplier: Shanghai Accela ChemBio Co., Ltd. CAS# 140924-50-1) (4.47 g, 5.73 mmol) in propan-l-ol (57 mL), a solution of (E)-6-(2,6-dichloropyridin-3-yl)hex-5-en-2-one (14 g, 57.34 mmol) in propan-l- ol (57 mL) and a mixture of potassium osmate(VI) dihydrate (2.11 g, 5.73 mmol) and NaOH (0.4 N in H2O, 14 mL) at 0 °C. The resulting mixture was stirred at room temperature for 16 h. The reaction mixture was extracted with EtOAc. The organic layer was dried over anhydrous Na2SO4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-60% ethyl acetate in petroleum ether to afford rel-tert-butyl ((lS,2S)-l-(2,6-dichloropyridin-3-yl)-2-hydroxy-5- oxohexyl)carbamate (6.05 g, 28%) as a yellow oil. MS ESI calculated for C16H22CI2N2O4 [M+H]⁺, 377.10; found, 377.00.

Step-3:

[1433] To a solution of rel-tert-butyl ((lS,2S)-l-(2,6-dichloropyridin-3-yl)-2-hydroxy-5- oxohexyl)carbamate (2.0 g, 5.30 mmol) in DCM (18 mL) was added TFA (6 mL). The mixture was stirred at room temperature for 1 h. The resulting mixture was concentrated under vacuum. The residue was basified with saturated NaHCCh (aq.) to pH 8. The mixture was extracted with EtOAc. The organic layer was dried over anhydrous Na2SC>4. After filtration, the filtrate was concentrated under reduced pressure. The residue was dissolved in i-PrOH (20 mL), then Pt/C (10%, 30 mg) was added. The mixture was hydrogenated at room temperature overnight under hydrogen atmosphere. The mixture was filtered through a Celite pad. The filtrate was concentrated under reduced pressure to afford rel-(2R,3R,6S)-2-(2,6- dichloropyridin-3-yl)-6-methylpiperidin-3-ol (1.02 g, crude) as a brown oil. MS ESI calculated for C11H14CI2N2O [M+H]⁺, 261.05; found, 261.00.

Step-4:

[1434] To a solution of rel-(2R,3R,6S)-2-(2,6-dichloropyridin-3-yl)-6-methylpiperidin-3-ol (980 mg, 3.75 mmol) in tert-Amyl alcohol (40 mL) was added t-BuOK (505 mg, 4.50 mmol). The mixture was stirred at 60 °C for 16 h under nitrogen atmosphere. The resulting mixture was concentrated under vacuum and then quenched with water. The resulting mixture was extracted with EtOAc. The organic layer was dried over anhydrous Na2SO4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by reverse phase flash column chromatography with 5% to 50% MeCN in water (10 mmol/L NH4HCO3) to afford rel-(2R,4aS,9bS)-7-chloro-2-methyl-l,2,3,4,4a,9b-hexahydrofuro[2,3-b:4,5- b']dipyridine (313 mg, 37%) as a yellow solid. MS ESI calculated for C11H13CIN2O [M+H]⁺, 225.07; found, 225.00.

Step-5

[1435] To a stirred solution of rel-(2R,4aS,9bS)-7-chloro-2-methyl-l,2,3,4,4a,9b- hexahydrofuro[2,3-b:4,5-b']dipyridine (710 mg, 3.16 mmol) and 4,4,5,5-tetramethyl-2-(prop- l-en-2-yl)-l,3,2-dioxaborolane (796 mg, 4.74 mmol) in 1,4-dioxane (10 mL) and H2O (2 mL) were added K2CO3 (655 mg, 4.74 mmol) and Pd(dppf)C12-CH2C12 (258 mg, 0.31 mmol) at room temperature. The resulting mixture was stirred at 80 °C for 2 h under nitrogen atmosphere. The mixture was allowed to cool down to room temperature and quenched with water. The mixture was extracted with EtOAc. The organic layer was dried over anhydrous Na2SC>4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0 - 10% methanol in dichloromethane to afford rel-(2R,4aS,9bS)-2-methyl-7-(prop-l-en-2-yl)-l,2,3,4,4a,9b- hexahydrofuro[2,3-b:4,5-b']dipyridine (950 mg, crude) as a brown oil. MS ESI calculated for C14H18N2O [M+H]⁺, 231.14; found, 231.10.

Step-6

[1436] To a solution of rel-(2R,4aS,9bS)-2-methyl-7-(prop-l-en-2-yl)-l,2,3,4,4a,9b- hexahydrofuro[2,3-b:4,5-b']dipyridine (950 mg, 4.12 mmol) in i-PrOH (10 mL) was added Pd/C (10%) (439 mg). The mixture was hydrogenated at room temperature for 16 h under hydrogen atmosphere. The mixture was filtered through a Celite pad. The filtrate was concentrated under reduced pressure. The residue was purified by reverse phase flash column chromatography with 5% to 50% MeCN in Water (10 mmol/L NH4HCO3) to afford rel- (2R,4aS,9bS)-7-isopropyl-2-methyl-l,2,3,4,4a,9b-hexahydrofuro[2,3-b:4,5-b']dipyridine (420 mg, 56% over two steps) as a yellow solid. MS ESI calculated for C14H20N2O [M+H]⁺, 233.16; found, 233.10. 'H NMR (400 MHz, DMSO-d₆) 57.56 (d, J = 7.2 Hz, 1H), 6.74 (d, J = 7.2 Hz, 1H), 4.34 - 4.30 (m, 1H), 4.11 - 4.07 (m, 1H), 2.92 - 2.83 (m, 1H), 2.61 - 2.54 (m, 1H), 2.24 - 2.15 (m, 1H), 1.92 - 1.82 (m, 1H), 1.70 (s, 1H), 1.52 - 1.43 (m, 1H), 1.26 - 1.10 (m, 7H), 0.94 (d, J = 6.4 Hz, 3H). Absolute stereochemistry was not determined.

Intermediate A78: (4aS,6R,10bS)-8-chloro-6-methyl-2,3,4,4a,6,10b-hexahydro-lH- pyrano[3,2-b:5,4-b']dipyridine hydrochloride

A78

Step 1: [1437] To a stirred solution of 3-bromo-6-chloropicolinic acid (50 g, 211.46 mmol) and N,O-dimethylhydroxylamine hydrochloride (24.75 g, 253.75 mmol) in DMF (500 mL) were added DIEA (81.99 g, 634.38 mmol) and HATU (96.49 g, 253.75 mmol) at room temperature under nitrogen atmosphere. The resulting mixture was stirred for 16 h at room temperature. The resulting mixture was quenched by water and extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SO4. After filtration, the filtrate was concentrated under reduced pressure. The resulting residue was purified by Combi Flash (Biotage Isolera Prime) with a 330 g silica gel column eluted with 0-40% ethyl acetate in petroleum ether to afford 3-bromo-6-chloro-N-methoxy-N-methylpicolinamide (41.9 g, 70% yield) as a white solid. MS ESI calculated for C₈H₈BrClN₂O₂ [M+H]⁺, 278.95, 280.95; found, 278.85, 280.85.

Step 2:

[1438] To a stirred solution of 3-bromo-6-chloro-N-methoxy-N-methylpicolinamide (40.9 g, 146.32 mmol) in THF (200 mL) was added chloro(methyl)magnesium (3M in EtiO) (146 mL, 438 mmol) at 0 °C under nitrogen atmosphere. The resulting mixture was stirred at room temperature for 2 h. The reaction was quenched by water and extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SO4. After filtration, the filtrate was concentrated under reduced pressure. The resulting residue was purified by Combi Flash (Biotage Isolera Prime) using a 330 g silica gel column eluted with 0-30% ethyl acetate in petroleum ether to afford l-(3-bromo-6-chloropyridin-2-yl)ethan-l- one (20 g, 58% yield) as a yellow oil. MS ESI calculated for CvHsBrCINO [M+H]⁺, 233.92, 235.92; found, 233.95, 235.95.

Step 3:

[1439] To a stirred solution of l-(3-bromo-6-chloropyridin-2-yl)ethan-l-one (19.5 g, 83.16 mmol) in methanol (200 mL) was added NaBFL (6.29 g, 166.32 mmol) at 0 °C under nitrogen atmosphere. The resulting mixture was stirred at room temperature for 16 h. The reaction was quenched by the addition of ice water at 0 °C. The resulting mixture was extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na₂SO4. After filtration, the filtrate was concentrated under reduced pressure. The resulting residue was purified by Combi Flash (Biotage Isolera Prime) using a 330 g silica gel column eluted with 0-25% ethyl acetate in petroleum ether to afford a 1:1 mixture of (R)-l- (3-bromo-6-chloropyridin-2-yl)ethan- l-ol and (S)- 1 -(3-bromo-6-chloropyridin-2-yl)ethan- 1 - ol (19 g, 96% yield) as a white solid. MS ESI calculated for C₇H₇BrClNO [M+H]⁺, 235.94, 237.94; found, 235.95, 237.95.

Step 4:

[1440] To a stirred solution of 1:1 mixture of (R)-l-(3-bromo-6-chloropyridin-2-yl)ethan-

1-ol and (S)-l-(3-bromo-6-chloropyridin-2-yl)ethan-l-ol (18.5 g, 78.22 mmol) and Imidazole (10.65 g, 156.45 mmol) in DCM (5 mL) was added tert-butyl(chloro)dimethylsilane (11.79 g, 78.22 mmol) at room temperature under nitrogen atmosphere. The resulting mixture was stirred at room temperature for 16 h. The reaction mixture was concentrated under vacuum. The resulting residue was purified by Combi Flash (Biotage Isolera Prime) using a 330 g silica gel column eluted with 0-15% ethyl acetate in petroleum ether to afford a 1:1 mixture of (R)-3-bromo-2-(l-((tert-butyldimethylsilyl)oxy)ethyl)-6-chloropyridine and (S)-3-bromo-

2-(l-((tert-butyldimethylsilyl)oxy)ethyl)-6-chloropyridine (27 g, 98% yield) as a colorless oil. MS ESI calculated for Ci₃H₂iBrClNOSi [M+H]⁺, 350.02, 352.02 ; found, 350.00, 352.00.

Step 5:

[1441] To a stirred solution of 1: 1 mixture of (R)-3-bromo-2-(l-((tert- butyldimethylsilyl)oxy)ethyl)-6-chloropyridine and (S)-3-bromo-2-(l -((tert- butyldimethylsilyl)oxy)ethyl)-6-chloropyridine (16 g, 45.61 mmol) and tert-butyl 3- oxopiperidine- 1 -carboxylate (9.09 g, 45.61 mmol) in toluene (340 mL) were added K3PO4 (23.24 g, 109.47 mmol) and Pd(t-BusP)2 (1.63 g, 3.19 mmol) at room temperature under nitrogen atmosphere. The resulting mixture was stirred for 3 h at 60 °C under nitrogen atmosphere. The resulting mixture was concentrated under reduced pressure. The residue was quenched with water and extracted with CH2CI2. The combined organic layers were washed with brine, dried over anhydrous Na2SO4. After filtration, the filtrate was concentrated under reduced pressure. The resulting residue was purified by Combi Flash (Biotage Isolera Prime) using a 330 g silica gel column eluted with 0-20% ethyl acetate in petroleum ether to afford a 1 :1 : 1 : 1 mixture of tert-butyl (S)-2-(2-((R)-l-((tert-butyldimethylsilyl)oxy)ethyl)-6- chloropyridin-3-yl)-3-oxopiperidine-l -carboxylate and tert-butyl (S)-2-(2-((S)-l-((tert- butyldimethylsilyl)oxy)ethyl)-6-chloropyridin-3-yl)-3-oxopiperidine- 1-carboxylate and tertbutyl (R)-2-(2-((S)- 1 -((tert-butyldimethylsilyl)oxy)ethyl)-6-chloropyridin-3-yl)-3- oxopiperidine- 1-carboxylate and tert-butyl (R)-2-(2-((R)-l-((tert- butyldimethylsilyl)oxy)ethyl)-6-chloropyridin-3-yl)-3-oxopiperidine-l-carboxylate (3.3 g, 15% yield) as a yellow oil. MS ESI calculated for C23H3?ClN2O4Si [M+H]⁺, 469.22; found, 469.20.

[1442] To a stirred solution of 1: 1: 1 : 1 mixture of tert-butyl (S)-2-(2-((R)-l-((tert- butyldimethylsilyl)oxy)ethyl)-6-chloropyridin-3-yl)-3-oxopiperidine- 1 -carboxylate and tertbutyl (S)-2-(2-((S)- 1 -((tert-butyldimethylsilyl)oxy)ethyl)-6-chloropyridin-3-yl)-3- oxopiperidine- 1-carboxylate and tert-butyl (R)-2-(2-((S)-l-((tert- butyldimethylsilyl)oxy)ethyl)-6-chloropyridin-3-yl)-3-oxopiperidine- 1-carboxylate and tertbutyl (R)-2-(2-((R)-l-((tert-butyldimethylsilyl)oxy)ethyl)-6-chloropyridin-3-yl)-3- oxopiperidine- 1 -carboxylate (3.30 g, 7.03 mmol) and l,4-diazabicyclo[2.2.2]octane hexahydrate (8.37 g, 37.98 mmol) in MeCN (20 mL) were added HCOOH (0.94 g, 20.40 mmol) and RuCl(p-cymene)[(S,S)-Ts-DPEN] (0.13 g, 0.21 mmol) at 0 °C under nitrogen atmosphere. The resulting mixture was stirred at 0 °C for 3 h. The resulting mixture was quenched by water extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SC>4. After filtration, the filtrate was concentrated under reduced pressure. The resulting residue was purified by Combi Flash (Biotage Isolera Prime) using a 120 g silica gel column eluted with 0-25% ethyl acetate in petroleum ether to afford tert-butyl (2S,3S)-2-(2-((R)- 1 -((tert-butyldimethylsilyl)oxy)ethyl)-6-chloropyridin-3-yl)-3- hydroxypiperidine-1 -carboxylate (780 mg, 23% yield) as white solid. MS ESI calculated for C23H₃9ClN2O₄Si [M+H]⁺, 471.24; found, 471.40.

[1443] The purification process also afford tert-butyl (2S,3S)-2-(2-((S)-l-((tert- butyldimethylsilyl)oxy)ethyl)-6-chloropyridin-3-yl)-3-hydroxypiperidine- 1 -carboxylate (960 mg, 28% yield) as white solid. MS ESI calculated for C23H₃9ClN2O4Si [M+H]⁺, 471.24; found, 471.40.

Step 7:

[1444] To a stirred solution of tert-butyl (2S,3S)-2-(2-((S)-l-((tert- butyldimethylsilyl)oxy)ethyl)-6-chloropyridin-3-yl)-3-hydroxypiperidine-l-carboxylate (960 mg, 2.03 mmol) in THF (10 mL) was added TBAF (639 mg, 2.44 mmol) at room temperature. The resulting mixture was stirred for 16 h at room temperature. The resulting mixture was concentrated under reduced pressure. The resulting residue was purified by Combi Flash (Biotage Isolera Prime) using a 40 g silica gel column eluted with 0-70% ethyl acetate in petroleum ether to afford tert-butyl (2S,3S)-2-(6-chloro-2-((S)-l- hydroxyethyl)pyridin-3-yl)-3-hydroxypiperidine-l -carboxylate (750 mg, 96% yield) as a white solid. MS ESI calculated for C17H25CIN2O4 [M+H]⁺, 357.15; found, 357.15.

Step 8:

[1445] To a stirred solution of tert-butyl (2S,3S)-2-(6-chloro-2-((S)-l- hydroxyethyl)pyridin-3-yl)-3-hydroxypiperidine-l -carboxylate (750 mg, 2.10 mmol) in toluene (8 mL) was added 2-(tributyl-A,⁵-phosphaneylidene)acetonitrile (CAS No. 157141-27- 0) (1014 mg, 4.20 mmol) at room temperature under nitrogen atmosphere. The resulting mixture was stirred at 110 °C for 16 h. The resulting mixture was concentrated under reduced pressure. The residue was purified by Combi Flash (Biotage Isolera Prime) using a 40 g silica gel column eluted with 0-12% ethyl acetate in petroleum ether to afford tert-butyl (4aS,6R, 10bS)-8-chloro-6-methyl-2,3,4,4a,6, lOb-hexahydro- lH-pyrano[3,2-b:5,4- b']dipyridine-l -carboxylate (540 mg, 75% yield) as a yellow oil. MS ESI calculated for C17H23CIN2O3 [M+H]⁺, 339.14; found, 339.10. Absolute stereochemistry was determined by NOESY.

Step 9:

A78

[1446] A mixture of tert-butyl (4aS,6R, 10bS)-8-chloro-6-methyl-2,3,4,4a,6, 10b- hexahydro-lH-pyrano[3,2-b:5,4-b']dipyridine-l-carboxylate (540 mg, 1.59 mmol) and HCl in 1,4-dioxane (4.0 M) (5.5 mL) was stirred at room temperature for 2 h. The resulting mixture was concentrated under reduced pressure to afford (4aS,6R,10bS)-8-chloro-6-methyl- 2,3,4,4a,6,10b-hexahydro-lH-pyrano[3,2-b:5,4-b']dipyridine hydrochloride (A78) (crude, 373 mg) as a white solid. MS ESI calculated for C12H15CIN2O [M+H]⁺, 239.09; found, 239.10. *H NMR (400 MHz, DMSO-d₆) 5 10.37 (s, 1H), 8.66 (s, 1H), 8.14 (d, J = 8.0 Hz, 1H), 7.56 (d, J = 8.0 Hz, 1H), 4.88 - 4.82 (m, 1H), 4.41 (d, J = 7.2 Hz, 1H), 4.11 - 4.02 (m, 1H), 3.27 - 3.18 (m, 1H), 3.12 - 2.96 (m, 1H), 2.09 - 1.94 (m, 1H), 1.94 - 1.78 (m, 2H), 1.77 - 1.64 (m, 1H), 1.58 (d, J = 6.8 Hz, 3H).

Intermediate A79 isomer 1: rel-(4R,4aS,9bR)-4-fluoro-7-(trifluoromethyl)-l,2,3,4,4a,9b- hexahydrofuro[2,3-b:4,5-b']dipyridine isomer 1

[1447] To a stirred solution of 3-bromo-2-chloro-6-(trifluoromethyl)pyridine (10 g, 38.40 mmol) in 1,4-dioxane (100 mL) and H2O (10 mL) were sequentially added Pd(dppf)Ch- CH2CI2 (3.14 g, 3.84 mmol), a 1:1 mixture of (R,E)-2,2,3,3,10,10-hexamethyl-9,9-diphenyl- 5-(2-(4,4,5,5-tetramethyl-l,3,2-dioxaborolan-2-yl)vinyl)-4,8-dioxa-3,9-disilaundecane and (S,E)-2,2,3,3,10,10-hexamethyl-9,9-diphenyl-5-(2-(4,4,5,5-tetramethyl-l,3,2-dioxaborolan-2- yl)vinyl)-4,8-dioxa-3,9-disilaundecane (from A46) (22.30 g, 38.40 mmol) and K2CO3 (15.92 g, 115.19 mmol). The resulting solution was stirred at 100 °C for 16 h. The resulting solution was quenched with water. The aqueous layer was extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SC>4. The residue was purified by silica gel column chromatography, eluted with PE / EtOAc (10: 1) to afford a 1 : 1 mixture of (R,E)-3-(3-((tert-butyldimethylsilyl)oxy)-5-((tert-butyldiphenylsilyl)oxy)pent- 1- en- l-yl)-2-chloro-6-(trifluoromethyl)pyridine and (S,E)-3-(3-((tert-butyldimethylsilyl)oxy)-5- ((tert-butyldiphenylsilyl)oxy)pent- 1 -en- 1 -yl)-2-chloro-6-(trifluoromethyl)pyridine (11.50 g, 72%) as a yellow oil. MS ESI calculated for C33H43ClF3NO2Si2 [M+H]⁺, 634.25; found, 634.15. Step-2:

[1448] To a stirred solution of 1: 1 mixture of (R,E)-3-(3-((tert-butyldimethylsilyl)oxy)-5- ((tert-butyldiphenylsilyl)oxy)pent- 1 -en- 1 -yl)-2-chloro-6-(trifluoromethyl)pyridine and (S ,E)- 3-(3-((tert-butyldimethylsilyl)oxy)-5-((tert-butyldiphenylsilyl)oxy)pent-l-en-l-yl)-2-chloro- 6-(trifluoromethyl)pyridine (11.50 g, 18.13 mmol) in THF (5 mL) were added AcOH (15 mL) and H2O (5 mL). The resulting solution was stirred at room temperature for 16 h. The resulting solution was quenched with water. The mixture was neutralized to pH 8 with NaHCCh (sat.). The aqueous layer was extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SC>4. The resulting mixture was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with PE / EtOAc (5:1) to afford a 1:1 mixture of (R,E)-5-((tert- butyldiphenylsilyl)oxy)-l-(2-chloro-6-(trifluoromethyl)pyridin-3-yl)pent-l-en-3-ol and (S,E)- 5-((tert-butyldiphenylsilyl)oxy)- 1 -(2-chloro-6-(trifluoromethyl)pyridin-3-yl)pent- 1 -en-3-ol (5.50 g, 68%) as a yellow oil. MS ESI calculated for C2₇H2₉ClF3NO2Si [M+H]⁺, 520.16; found, 520.15.

Step-3:

[1449] To a stirred solution of a 1:1 mixture of (R,E)-5-((tert-butyldiphenylsilyl)oxy)-l-(2- chloro-6-(trifhioromethyl)pyridin-3-yl)pent- 1 -en-3-ol and (S,E)-5-((tert- butyldiphenylsilyl)oxy)- 1 -(2-chloro-6-(trifluoromethyl)pyridin-3-yl)pent- 1 -en-3-ol (5.50 g, 10.58 mmol) in DCM (55 mL) was added DAST (3.41 g, 21.15 mmol) dropwise at 0 °C. The resulting solution was stirred at room temperature for 2 h. The resulting solution was quenched with water at 0 °C. The aqueous layer was extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous NazSCh. The resulting mixture was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with PE / EtOAc (10:1) to afford a 1:1 mixture of (R,E)-3-(5-((tert- butyldiphenylsilyl)oxy)-3-fluoropent-l-en-l-yl)-2-chloro-6-(trifluoromethyl)pyridine and (S,E)-3-(5-((tert-butyldiphenylsilyl)oxy)-3-fluoropent-l-en-l-yl)-2-chloro-6- (trifhioromethyl)pyridine (3.50 g, 74%) as a yellow oil. MS ESI calculated for C27H₂8ClF₄NOSi [M+H]⁺, 522.16; found, 522.15.

Step-4:

[1450] To a stirred solution of BocNHz (557 mg, 4.75 mmol, 0.4 M in i-PrOH) were sequentially added NaOH (165 mg, 4.14 mmol, 0.4 M in water) and DCDMH (429 mg, 2.18 mmol) at 0 °C and was at 0 °C for 20 min. Then to above the mixture were sequentially added (DHQ)2PHAL (supplier: Shanghai Accela ChemBio Co., Ltd. CAS# 140924-50-1) (119 mg, 0.15 mmol, 0.1 M in i-PrOH), a solution of 1:1 mixture of (R,E)-3-(5-((tert- butyldiphenylsilyl)oxy)-3-fhioropent- 1 -en- 1 -yl)-2-chloro-6-(trifhioromethyl)pyridine and (S,E)-3-(5-((tert-butyldiphenylsilyl)oxy)-3-fluoropent-l-en-l-yl)-2-chloro-6- (trifhioromethyl)pyridine (800 mg, 1.53 mmol) in n-PrOH (5 mL) and K2OSO4.2H2O (56 mg, 0.15 mmol) at 0 °C. The resulting solution was stirred at room temperature for 16 h. The resulting solution was quenched with water. The aqueous layer was extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SO4.The resulting mixture was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with PE / EtOAc (5: 1) to afford a 1 : 1 mixture of tertbutyl ((lR*,2S*,3R)-5-((tert-butyldiphenylsilyl)oxy)-l-(2-chloro-6-(trifluoromethyl)pyridin- 3-yl)-3-fluoro-2-hydroxypentyl)carbamate and tert-butyl ((lR*,2S*,3S)-5-((tert- butyldiphenylsilyl)oxy)-l-(2-chloro-6-(trifluoromethyl)pyridin-3-yl)-3-fluoro-2- hydroxypentyl)carbamate (600 mg, 80%) as a colorless oil. MS ESI calculated for C32H₃9ClF4N₂O4Si [M+H]⁺, 655.23; found, 655.15.

Step-5:

[1451] To a stirred solution of a 1:1 mixture of tert-butyl ((lR*,2S*,3R)-5-((tert- butyldiphenylsilyl)oxy)-l-(2-chloro-6-(trifluoromethyl)pyridin-3-yl)-3-fluoro-2- hydroxypentyl)carbamate and tert-butyl ((lR*,2S*,3S)-5-((tert-butyldiphenylsilyl)oxy)-l-(2- chloro-6-(trifluoromethyl)pyridin-3-yl)-3-fluoro-2-hydroxypentyl)carbamate (1.00 g, 1.53 mmol) in toluene (10 mL) were added CS2CO3 (1.49 g, 4.58 mmol), JohnPhos (0.05 g, 0.15 mmol) and Pd(OAc)2 (0.03 g, 0.15 mmol). The resulting solution was stirred at 100 °C for 16 h under nitrogen atmosphere. The resulting solution was quenched with water and extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SC>4. The resulting mixture was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with PE / EtOAc (8 : 1 ) to afford a 1 : 1 mixture of tert-butyl ((2R*,3S*)-2-((R)-3-((tert-butyldiphenylsilyl)oxy)-l-fluoropropyl)-6- (trifhioromethyl)-2,3-dihydrofuro[2,3-b]pyridin-3-yl)carbamate andtert-butyl ((2R*,3S*)-2- ((S)-3-((tert-butyldiphenylsilyl)oxy)-l-fluoropropyl)-6-(trifluoromethyl)-2,3-dihydrofuro[2,3- b]pyridin-3-yl)carbamate (260 mg, 88%) as a yellow oil. MS ESI calculated for C27H₂9ClF₃NO2Si [M+H]⁺, 618.25; found, 618.15.

Step-6: [1452] To a stirred solution of a 1:1 mixture of tert-butyl ((2R*,3S*)-2-((R)-3-((tert- butyldiphenylsilyl)oxy)-l-fhioropropyl)-6-(trifhioromethyl)-2,3-dihydrofuro[2,3-b]pyridin-3- yl)carbamate andtert-butyl ((2R*,3S*)-2-((S)-3-((tert-butyldiphenylsilyl)oxy)- 1- fluoropropyl)-6-(trifluoromethyl)-2,3-dihydrofuro[2,3-b]pyridin-3-yl)carbamate (1.30 g, 2.10 mmol) in THF (13 mL) was added TBAF (1.37 g, 5.25 mmol) at 0 °C. The resulting solution was stirred at room temperature for 2 h. The resulting mixture was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with PE / EtOAc (1:1) to afford a 1:1 mixture of tert-butyl ((2R*,3S*)-2-((R)- l-fhioro-3- hydroxypropyl)-6-(trifhioromethyl)-2,3-dihydrofuro[2,3-b]pyridin-3-yl)carbamate and tert- butyl ((2R*,3S*)-2-((S)-l-fhioro-3-hydroxypropyl)-6-(trifluoromethyl)-2,3-dihydrofuro[2,3- b]pyridin-3-yl)carbamate (900 mg, 80%) as a yellow oil. MS ESI calculated for (C16H20F4N2O4) [M+H]⁺, 381.14; found, 381.15.

Step-7:

[1453] To a stirred solution of a 1:1 mixture of tert-butyl ((2R*,3S*)-2-((R)-l-fluoro-3- hydroxypropyl)-6-(trifluoromethyl)-2,3-dihydrofuro[2,3-b]pyridin-3-yl)carbamate and tertbutyl ((2R*,3S*)-2-((S)-l-fluoro-3-hydroxypropyl)-6-(trifluoromethyl)-2,3-dihydrofuro[2,3- b]pyridin-3-yl)carbamate (900 mg, 2.37 mmol) in toluene (10 mL) was added 2-(tributyl-X⁵- phosphaneylidene)acetonitrile (46.54 g, 192.82 mmol) (CAS No. 157141-27-0) (1.14 g, 4.73 mmol). The resulting solution was stirred at 100 °C for 16 h under nitrogen atmosphere. The resulting mixture was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with PE / EtOAc (3:1) to afford rel-tert-butyl (4R,4aS,9bR)-4-fhioro-7-(trifluoromethyl)-3,4,4a,9b-tetrahydrofuro[2,3-b:4,5-b']dipyridine- l(2H)-carboxylate isomer 1 (140 mg, 75%) as a white solid with the first eluting peak. MS ESI calculated for C16H18F4N2O3 [M+H]⁺, 363.13; found, 363.15. ¹H NMR (400 MHz, DMSO-d₆) 8 7.75 (d, J = 7.6 Hz, 1H), 7.51 (d, J = 7.2 Hz, 1H), 6.13 (d, J = 9.2 Hz, 1H), 5.17 - 5.04 (m, 1H), 4.92 - 4.70 (m, 1H), 4.08 - 3.89 (m, 1H), 2.79 - 2.77 (m, 1H), 1.99 - 1.89 (m, 1H), 1.81 - 1.66 (m, 1H), 1.48 (s, 9H).

[1454] The purification process also afford rel-tert-butyl (4R,4aS,9bR)-4-fluoro-7- (trifhioromethyl)-3,4,4a,9b-tetrahydrofuro[2,3-b:4,5-b']dipyridine- 1 (2H)-carboxylate isomer 2 (90 mg, 62%) as a white solid with the second eluting peak. MS ESI calculated for C16H18F4N2O3 [M+H]⁺, 363.13; found, 363.20. ¹H NMR (400 MHz, DMSO-J₆) 87.73 (d, J = 7.6 Hz, 1H), 7.46 (d, J = 7.2 Hz, 1H), 5.98 (d, J = 9.2 Hz, 1H), 5.30 - 5.02 (m, 2H), 3.85 - 3.84 (m, 1H), 2.99 - 2.76 (m, 1H), 1.98 - 1.83 (m, 2H), 1.48 (s, 9H).

Step-8: isomer 1 A79 isomer 1

[1455] A mixture of rel-tert-butyl (4R,4aS,9bR)-4-fluoro-7-(trifhioromethyI)-3,4,4a,9b- tetrahydrofuro[2,3-b:4,5-b']dipyridine-l(2H)-carboxylate isomer 1 (140 mg, 0.39 mmol) and HC1 (4.0 M in 1,4-dioxane) (2 mL) was stirred at 0 °C for 2 h. The resulting mixture was concentrated under reduced pressure to afford rel-(4R,4aS,9bR)-4-fluoro-7-(trifluoromethyl)- l,2,3,4,4a,9b-hexahydrofuro[2,3-b:4,5-b']dipyridine hydrochloride isomer 1 (A79 isomer 1) (120 mg, crude) as a yellow solid. MS ESI calculated for C11H10F4N2O [M+H]⁺, 263.07; found, 263.15. 'H NMR (400 MHz, DMSO- ₆) 8 11.09 (br, 1H), 9.63 (br, 1H), 8.37 (d, J = 7.6 Hz, 1H), 7.67 (d, J= 7.6 Hz, 1H), 5.42 - 5.23 (m, 2H), 5.16 - 5.05 (m, 1H), 3.26 - 3.11 (m, 2H), 2.22 - 2.09 (m, 2H). Absolute stereochemistry was not determined.

Intermediate A79 isomer 2: rel-(4R,4aS,9bR)-4-fluoro-7-(trifluoromethyl)-l ,2, 3, 4, 4a, 9b- hexahydrofuro[2,3-b:4,5-b']dipyridine isomer 2

A79 isomer 2

Step-1: isomer 2 A79 isomer 2

[1456] A mixture of rel-tert-butyl (4R,4aS,9bR)-4-fluoro-7-(trifluoromethyl)-3,4,4a,9b- tetrahydrofuro[2,3-b:4,5-b']dipyridine-l(2H)-carboxylate isomer 1 (90 mg, 0.25 mmol) and HC1 (4.0 M in 1,4-di oxane) (2 mL) was stirred at 0 °C for 2 h. The resulting mixture was concentrated under reduced pressure to afford rel-(4R,4aS,9bR)-4-fluoro-7-(trifluoromethyl)- l,2,3,4,4a,9b-hexahydrofuro[2,3-b:4,5-b']dipyridine hydrochloride isomer 2 (A79 isomer 2) (60 mg, crude) as a yellow solid. MS ESI calculated for C11H10F4N2O [M+H]⁺, 263.07; found, 263.15. 'H NMR (400 MHz, DMSO- ₆) 8 11.11 (br, 1H), 9.12 (br, 1H), 8.30 (d, J = 7.2 Hz, 1H), 7.65 (d, J = 7.6 Hz, 1H), 5.44 - 5.18 (m, 3H), 3.29 - 3.19 (m, 1H), 3.18 - 3.10 (m, 1H), 2.27 - 2.03 (m, 2H). Absolute stereochemistry was not determined.

Intermediate A80 isomer 1: rel-(4R,4aS,10bS)-4-methyl-8-(trifluoromethyl)-2,3,4,4a,6,10b- hexahydro-lH-pyrano[3,2-b:5,4-b']dipyridine isomer 1

A80 isomer 1

Step-1:

[1457] To a mixture of 1 : 1 mixture of (R)-3-methyldihydrofuran-2(3H)-one and (S)-3- methyldihydrofuran-2(3H)-one (30 g, 299.65 mmol) in DCM (600 mL) was added DIBAL-H (1.0 M in DCM) (389 mL, 389 mmol) dropwise at -78 °C under nitrogen atmosphere. The resulting mixture was stirred at -78 °C for 1 h under nitrogen atmosphere. The reaction mixture was quenched by the addition of ice water and extracted with dichloromethane. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered through paper, and concentrated under vacuum to afford a 1 : 1 : 1 : 1 mixture of (2R,3R)-3-methyltetrahydrofuran-2-ol and (2S,3S)-3-methyltetrahydrofuran-2-ol and (2R,3S)-3-methyltetrahydrofuran-2-ol and (2S,3R)-3-methyltetrahydrofuran-2-ol (26.4 g, crude) as a yellow oil. 'H NMR (400 MHz, DMSO-d₆) 8 6.05 - 5.63 (m, 1H), 5.18 - 4.67 (m, 1H), 3.99 - 3.50 (m, 2H), 2.20 - 1.81 (m, 2H), 1.64 - 1.28 (m, 1H), 1.00 - 0.89 (m, 3H).

Step-2:

[1458] To a mixture of 1 : 1 : 1: 1 mixture of (2R,3R)-3-methyltetrahydrofuran-2-ol and (2S,3S)-3-methyltetrahydrofuran-2-ol and (2R,3S)-3-methyltetrahydrofuran-2-ol and (2S,3R)-3-methyltetrahydrofuran-2-ol (25.40 g, 248.69 mmol) and dimethyl (l-diazo-2- oxopropyl)phosphonate (52.55 g, 273.56 mmol) in methanol (1250 mL) was added K2CO3 (68.74 g, 497.39 mmol) at room temperature. The resulting mixture was stirred at room temperature for 16 h. The resulting mixture was filtered, the filter cake was washed with methanol. The filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with PE / EtOAc ( 1 : 1 ) to afford a 1 : 1 mixture of (R)-3-methylpent-4-yn-l-ol and (S)-3-methylpent-4-yn-l-ol (15.90 g, 65%) as a yellow oil. 'H NMR (400 MHz, CDCI3) 8 3.96 - 3.70 (m, 2H), 2.75 - 2.52 (m, 1H), 2.10 (d, J = 2.4 Hz, 1 H), 1 .96 - 1.86 (m, 1 H), 1.77 - 1 .58 (m, 2H), 1 .24 (d, J = 6.8 Hz, 3H).

Step-3: [1459] To a mixture of 1:1 mixture of (R)-3-methylpent-4-yn-l-ol and (S)-3-methylpent-4- yn-l-ol (22.9 g, 233.33 mmol) and TBDPSC1 (70.55 g, 256.66 mmol) in DMF (340 mL) was added imidazole (63.54 g, 933.31 mmol) at room temperature. The resulting mixture was stirred at room temperature for 16 h. The resulting mixture was quenched with water and extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SO₄. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with PE / EtOAc (10: 1) to afford a 1:1 mixture of (R)-tert-butyl((3-methylpent-4-yn-l-yl)oxy)diphenylsilane and (S)- tert-butyl((3-methylpent-4-yn-l-yl)oxy)diphenylsilane (62 g, 78%) as a colorless oil. ¹H NMR (400 MHz, DMSO) 8 7.75 - 7.56 (m, 4H), 7.50 - 7.38 (m, 6H), 3.87 - 3.66 (m, 2H), 2.84 (d, 7 = 2.4 Hz, 1H), 2.70 - 2.62 (m, 1H), 1.80 - 1.54 (m, 2H), 1.12 (d, J = 7.2 Hz, 3H), 1.00 (s, 9H).

Step-4:

[1460] To a 1:1 mixture of (R)-tert-butyl((3-methylpent-4-yn-l-yl)oxy)diphenylsilane and (S)-tert-butyl((3-methylpent-4-yn-l-yl)oxy)diphenylsilane (31.10 g, 92.41 mmol) and Schwartz reagent (4.75 g, 18.48 mmol) were added 4, 4, 5, 5-tetramethyl- 1,3, 2- dioxaborolane (29.57 g, 231.02 mmol) and Et₃N (5.61 g, 55.44 mmol) at room temperature. The resulting mixture was stirred at 60 °C for 16 h. The reaction mixture purified by silica gel column chromatography, eluted with PE / EtOAc (5 : 1 ) to afford a 1 : 1 mixture of (R,E)-tert-butyl((3-methyl-5-(4,4,5,5-tetramethyl- 1 ,3,2-dioxaborolan-2-yl)pent-4- en-l-yl)oxy)diphenylsilane and (S,E)-tert-butyl((3-methyl-5-(4, 4,5, 5-tetramethyl- 1,3,2- dioxaborolan-2-yl)pent-4-en-l-yl)oxy)diphenylsilane (34 g, 79%) as a light yellow oil. MS ESI calculated for C₂8H₄iBO₃Si [M+H]⁺, 465.29; found, 465.35.

Step-5:

[1461] To a mixture of (R,E)-tert-butyl((3-methyl-5-(4, 4, 5, 5-tetramethyl- 1 ,3,2- dioxaborolan-2-yl)pent-4-en-l-yl)oxy)diphenylsilane and (S,E)-tert-butyl((3-methyl-5- (4,4,5,5-tetramethyl-l,3,2-dioxaborolan-2-yl)pent-4-en-l-yl)oxy)diphenylsilane (10.29 g, 22.14 mmol) and ethyl 3-bromo-6-(trifluoromethyl)picolinate (5.50 g, 18.45 mmol) in dioxane (70 mL) and H2O (7 mL) were added Pd(dppf)C12-CH2Ch (1.51 g, 1.84 mmol) and K2CO3 (7.65 g, 55.36 mmol) at room temperature under nitrogen atmosphere. The resulting mixture was stirred at 100 °C for 16 h. The resulting mixture was concentrated under vacuum. The residue was purified by silica gel column chromatography, eluted with PE / EtOAc (4: 1) to afford a 1 : 1 mixture of ethyl (S,E)-3-(5-((tert- butyldiphenylsilyl)oxy)-3-methylpent-l-en-l-yl)-6-(trifluoromethyl)picolinate and ethyl (S,E)-3-(5-((tert-butyldiphenylsilyl)oxy)-3-methylpent- 1 -en- 1 -yl)-6- (trifhioromethyl)picolinate (9.5 g, 92%) as a yellow oil. MS ESI calculated for C3iH₃6F₃NO3Si [M+H]⁺, 556.24; found, 556.20.

Step-6:

[1462] To a mixture of B0CNH2 (3.27 g, 27.89 mmol) in n-PrOH (35 mL) were added a solution of NaOH (0.97 g, 24.29mmol) in H2O (30.5 mL). Then l,3-dichloro-5,5- dimethylimidazolidine-2, 4-dione (2.66 g, 13.49 mmol) was added at room temperature. After stirring at room temperature for additional 30 min, a solution of (DHQ)2PHAL (supplier: Shanghai Accela ChemBio Co., Ltd. CAS# 140924-50-1) (0.70 g, 0.90 mmol) in n-PrOH (9 mL), a solution of 1:1 mixture of ethyl (S,E)-3-(5-((tert-butyldiphenylsilyl)oxy)-3- methylpent-l-en-l-yl)-6-(trifluoromethyl)picolinate and ethyl (S,E)-3-(5-((tert- butyldiphenylsilyl)oxy)-3-methylpent-l-en-l-yl)-6-(trifluoromethyl)picolinate (5 g, 8.99 mmol) in propan- l-ol (50 mL) and Potassium osmate(VI) dihydrate (0.33 g, 0.90 mmol) were added sequentially at 0 °C. The resulting mixture was stirred at room temperature for 16 h. The resulting mixture was quenched with water and extracted with EtOAc. The combined organic layers were dried over anhydrous Na2SO4. After filtration, the filtrate was concentrated under reduced pressure. The residue was dissolved in DCM (110 mL), then DCC (2.78 g, 13.49 mmol) and DMAP (0.11 g, 0.90 mmol) were added at room temperature. The resulting mixture was stirred at room temperature for 4 h. The reaction was quenched with water and extracted with DCM. The combined organic layers were dried over anhydrous Na2SO4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with PE / EtOAc (3:1) to afford a 1:1 mixture of tert-butyl ((5R*,6R*)-6-((S)-4-((tert-butyldiphenylsilyl)oxy)butan-2-yl)-8- oxo-2-(trifluoromethyl)-5,8-dihydro-6H-pyrano[3,4-b]pyridin-5-yl)carbamate and tert-butyl ((5R*,6R*)-6-((R)-4-((tert-butyldiphenylsilyl)oxy)butan-2-yl)-8-oxo-2-(trifluoromethyl)-5,8- dihydro-6H-pyrano[3,4-b]pyridin-5-yl)carbamate (2.40 g, 41%) as a brown oil. MS ESI calculated for C34H4iF3N2OsSi [M+H]⁺, 643.27; found, 643.20.

Step-7:

[1463] To a 1:1 mixture of tert-butyl ((5R*,6R*)-6-((S)-4-((tert- butyldiphenylsilyl)oxy)butan-2-yl)-8-oxo-2-(trifluoromethyl)-5,8-dihydro-6H-pyrano[3,4- b]pyridin-5-yl)carbamate and tert-butyl ((5R*,6R*)-6-((R)-4-((tert- butyldiphenylsilyl)oxy)butan-2-yl)-8-oxo-2-(trifluoromethyl)-5,8-dihydro-6H-pyrano[3,4- b]pyridin-5-yl)carbamate (2.70 g, 4.20 mmol) in THF (54 mL) was added NaBFU (238 mg, 6.30 mmol) at 0 °C. The resulting mixture was stirred at room temperature for 16 h. The reaction was quenched with ice water and extracted with EtOAc. The combined organic layers were dried over anhydrous Na2SC>4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with PE / EtOAc (1:1) to afford a 1:1 mixture of tert-butyl ((lR*,2R*,3S)-5-((tert- butyldiphenylsilyl)oxy)-2-hydroxy-l-(2-(hydroxymethyl)-6-(trifluoromethyl)pyridin-3-yl)-3- methylpentyl)carbamate and tert-butyl ((lR*,2R*,3R)-5-((tert-butyldiphenylsilyl)oxy)-2- hydroxy-l-(2-(hydroxymethyl)-6-(trifluoromethyl)pyridin-3-yl)-3-methylpentyl)carbamate (2.40 g, 88%) as an off-white solid. MS ESI calculated for C34H4sF3N2O5Si [M+H]⁺, 647.30; found, 647.70.

Step-8:

[1464] To a stirred solution of 1: 1 mixture of tert-butyl ((lR*,2R*,3S)-5-((tert- butyldiphenylsilyl)oxy)-2-hydroxy-l-(2-(hydroxymethyl)-6-(trifluoromethyl)pyridin-3-yl)-3- methylpentyl)carbamate and tert-butyl ((lR*,2R*,3R)-5-((tert-butyldiphenylsilyl)oxy)-2- hydroxy-l-(2-(hydroxymethyl)-6-(trifluoromethyl)pyridin-3-yl)-3-methylpentyl)carbamate (1.40 g, 2.16 mmol) in toluene (15 mL) was added 2-(tributyl-X⁵- phosphaneylidene)acetonitrile (CAS No. 157141-27-0) (0.78 g, 3.24 mmol) at room temperature. The resulting mixture was stirred at 110 °C for 16 h under nitrogen atmosphere. The resulting mixture was concentrated under vacuum. The residue was purified by silica gel column chromatography, eluted with PE / EtOAc (2:1) to afford a 1:1 mixture of tert-butyl ((5R*,6R*)-6-((S)-4-((tert-butyldiphenylsilyl)oxy)butan-2- yl)-2-(trifhioromethyl)-5,8-dihydro-6H-pyrano[3,4-b]pyridin-5-yl)carbamate and tert-butyl ((5R*,6R*)-6-((R)-4-((tert-butyldiphenylsilyl)oxy)butan-2-yl)-2-(trifluoromethyl)-5,8- dihydro-6H-pyrano[3,4-b]pyridin-5-yl)carbamate (420 mg, 30%) as an off-white solid. MS ESI calculated for C₃4H43F3N₂O4Si [M+H]⁺, 629.29; found, 629.25.

Step-9:

[1465] To a stirred solution of 1 : 1 mixture of tert-butyl ((5R*,6R*)-6-((S)-4-((tert- butyldiphenylsilyl)oxy)butan-2-yl)-2-(trifluoromethyl)-5,8-dihydro-6H-pyrano[3,4-b]pyridin- 5-yl)carbamate and tert-butyl ((5R*,6R*)-6-((R)-4-((tert-butyldiphenylsilyl)oxy)butan-2-yl)- 2-(trifhioromethyl)-5,8-dihydro-6H-pyrano[3,4-b]pyridin-5-yl)carbamate (400 mg, 0.64 mmol) in THF (4 mL) was added TBAF (332 mg, 1.27mmol) at 25 °C. The resulting solution was stirred at 25 °C for 16 h. The resulting mixture was quenched with water and extracted with EtOAc. The combined organic layers were dried over anhydrous Na₂SO4.

After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-50% ethyl acetate in petroleum ether to afford a 1:1 mixture of tert-butyl ((5R*,6R*)-6-((S)-4-hydroxybutan-2-yl)-2- (trifluoromethyl)-5,8-dihydro-6H-pyrano[3,4-b]pyridin-5-yl)carbamate and tert-butyl ((5R*,6R*)-6-((R)-4-hydroxybutan-2-yl)-2-(trifluoromethyl)-5,8-dihydro-6H-pyrano[3,4- b]pyridin-5-yl)carbamate (120 mg, 48%) as a white solid. MS ESI calculated for Ci8H₂₅F₃N₂O4 [M+H]⁺, 391.18; found, 391.10 Step- 10: isomer 1

[1466] To a 1:1 mixture of tert-butyl ((5R*,6R*)-6-((S)-4-hydroxybutan-2-yl)-2- (trifluoromethyl)-5,8-dihydro-6H-pyrano[3,4-b]pyridin-5-yl)carbamate and tert-butyl ((5R*,6R*)-6-((R)-4-hydroxybutan-2-yl)-2-(trifluoromethyl)-5,8-dihydro-6H-pyrano[3,4- b]pyridin-5-yl)carbamate (370 mg, 0.95 mmol) in toluene (8 mL) was added 2-(tributyl-X⁵- phosphaneylidene)acetonitrile (CAS No. 157141-27-0) (343 mg, 1.42 mmol) at room temperature. The resulting mixture was stirred at 100 °C for 16 h under nitrogen atmosphere. The resulting mixture was concentrated under vacuum. The crude product was purified by Prep-HPLC with the following conditions (Column: XBridge Prep OBD C18 Column30*150 mm; Mobile Phase A: Water(10 mmol/L NH4HCO3), Mobile Phase B: ACN; Flow rate: 60 mL/min; Gradient (B%): 5% B to 5% B in 2 min, 52% B to 72% B in 10 min; Wave Length: 254/220 nm; RTl(min): 8.9-9.6) to afford rel-tert-butyl (4R,4aS,10bS)-4-methyl-8- (trifluoromethyl)-2,3,4,4a,6, 1 Ob-hexahydro- 1 H-pyrano [3 ,2-b :5 ,4-b'] dipyridine- 1 -carboxylate isomer 1 (105 mg, 29%) as a colorless oil as the first eluting peak. MS ESI calculated for C18H23F3N2O [M+H]⁺, 373.17; found, 373.10.

[1467] rel-tert-butyl (4R,4aR,10bR)-4-methyl-8-(trifluoromethyl)-2,3,4,4a,6,10b- hexahydro-lH-pyrano[3,2-b:5,4-b']dipyridine-l-carboxylate isomer 2 (105 mg, 29%) as a colorless oil as the second eluting peak. MS ESI calculated for C18H23F3N2O [M+H]⁺, 373.17; found, 373.10

isomer 1

A80 isomer 1

[1468] A mixture of tert-butyl (4R,4aS,10bS)-4-methyl-8-(trifluoromethyl)-2,3,4,4a,6,10b- hexahydro-lH-pyrano[3,2-b:5,4-b']dipyridine-l -carboxylate (140 mg, 0.37 mmol) and hydrogen chloride(4.0 M in ethyl acetate) (2 mL) was stirred at room temperature for 1 h. The resulting mixture was concentrated under vacuum to afford rel- (4R,4aS,10bS)-4-methyl-8-(trifluoromethyl)-2,3,4,4a,6,10b-hexahydro-lH-pyrano[3,2-b:5,4- b']dipyridine hydrochloride isomer 1 (A80 isomer 1) (130 mg, crude) as a white solid. MS ESI calculated for C13H15F3N2O.HCI [M+H]⁺, 273.11; found, 273.15. 'H NMR (400 MHz, DMSO) 8 10.66 (br, 1H), 9.01 (br, 1H), 8.46 (dd, J = 8.8, 3.6 Hz, 1H), 7.96 (d, J = 8.0 Hz, 1H), 5.07 - 4.82 (m, 2H), 4.72 (s, 1H), 3.88 (t, J = 2.0 Hz, 1H), 3.25 - 3.12 (m, 1H), 3.09 - 3.00 (m, 1H), 2.28 - 2.16 (m, 1H), 2.12 - 1.97 (m, 1H), 1.60 - 1.41 (m, 1H), 1.13 (d, J= 7.2 Hz, 3H). Relative stereochemistry was determined by NOESY. Absolute stereochemistry was not determined.

Intermediate A80 isomer 2: rel-(4R,4aR,10bR)-4-methyl-8-(trifluoromethyl)-

2,3,4,4a,6,10b-hexahydro-lH-pyrano[3,2-b:5,4-b']dipyridine isomer 2

A80 isomer 2

Step-1: isomer 2

[1469] A mixture of rel-tert-butyl (4R,4aR, 10bR)-4-methyl- 8-(trifluoromethyl)- 2,3,4,4a,6,10b-hexahydro-lH-pyrano[3,2-b:5,4-b']dipyridine-l-carboxylate isomer 2 (130 mg, 0.35 mmol) and hydrogen chloride (4.0 M in ethyl acetate) (2 mL) was stirred at room temperature for 1 h. The resulting mixture was concentrated under vacuum to afford rel- (4R,4aR,10bR)-4-methyl-8-(trifluoromethyl)-2,3,4,4a,6,10b-hexahydro-lH-pyrano[3,2-b:5,4- b']dipyridine hydrochloride isomer 2 (A80 isomer 2) (120 mg, crude) as a white solid. MS ESI calculated for CI₃HI₅F₃N2O.HC1 [M+H]⁺, 273.11; found, 273.15,'H NMR (400 MHz, DMSO) 8 10.69 (br, 1H), 8.85 (br, 1H), 8.54 - 8.34 (m, 1H), 7.96 (d, J= 8.0 Hz, 1H), 5.00 (d, J = 16.4 Hz, 1H), 4.85 (d, J = 16.4 Hz, 1H), 4.54 (s, 1H), 4.00 - 3.83 (m, 1H), 3.22 (d, J = 12.8 Hz, 1H), 3.09 (s, 1H), 2.12 - 2.01 (m, 1H), 1.70 - 1.53 (m, 2H), 1.08 (d, J= 6.8 Hz, 3H). Relative stereochemistry was determined by NOESY. Absolute stereochemistry was not determined.

Intermediate A81 isomer 1: rel-(4R,4aR,9bS)-4-methoxy-7-(trifluoromethyl)-l,2,3,4,4a,9b- hexahydrofuro[2,3-b:4,5-b']dipyridine isomer 1

A81 isomer 1 _anj

Intermediate A81 isomer 2: rel-(4S,4aR,9bS)-4-methoxy-7-(trifluoromethyl)-l,2,3,4,4a,9b- hexahydrofuro[2,3-b:4,5-b']dipyridine isomer 2

A81 isomer 2

Step-1: * HO^^^'OTBDPS

[1470] To a stirred solution of propane- 1,3-diol (100.00 g, 1314.15 mmol) in DCM (200 mL) were added imidazole (223.66 g, 3285.37 mmol) and TBDPSC1 (397.33 g, 1445.56 mmol) at 0 °C. The resulting mixture was stirred at room temperature for 2 h. The resulting mixture was quenched with water. The resulting mixture was extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na₂SO4. The resulting mixture was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with PE / EtOAc (0 - 10%) to afford 3-((tert- butyldiphenylsilyl)oxy)propan-l-ol (136.9 g, 33%) as a colorless oil. MS ESI calculated for Ci₉H26O₂Si [M+H]⁺, 315.17; found, 315.15.

Step-2:

HO^^^OTBDPS - - O^^^^OTBDPS

[1471] To a stirred solution of 3-((tert-butyldiphenylsilyl)oxy)propan-l-ol (40.00 g, 127.19 mmol) in DCM (400 mL) was added TEA (38.61 g, 381.56 mmol) at room temperature. To the above mixture was added a solution of Py-SCh (40.49 g, 254.37 mmol) in DMSO (200 mL) at 0 ° C. The resulting mixture was stirred at room temperature for additional 2 h. The resulting mixture was quenched with water. The resulting mixture was extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na₂SO4. The resulting mixture was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0 - 15% EtOAc in PE to afford 3-((tert- butyldiphenylsilyl)oxy)propanal (31.00 g, 78%) as a colorless oil. MS ESI calculated for Ci₉H24O₂Si [M+H]⁺, 313.15; found, 313.15.

Step-3:

[1472] To a stirred solution of 3-((tert-butyldiphenylsilyl)oxy)propanal (31.00 g, 99.21 mmol) in THF (310 mL) was added Ethynyhnagnesium bromide (0.5 M solution in THF) (397 mL, 198.41 mmol) at 0 ° C dropwise under nitrogen atmosphere. The resulting mixture was stirred at room temperature for 2 h under nitrogen atmosphere. The reaction was quenched with NH4CI (sat.). The resulting mixture was extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na₂SO4. The resulting mixture was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0 - 10% EtOAc in PE to afford a 1 :1 mixture of (S)-5-((tert- butyldiphenylsilyl)oxy)pent-l-yn-3-ol and (R)-5-((tert-butyldiphenylsilyl)oxy)pent-l-yn-3-ol (19.20 g, 57%) as a yellow oil. MS ESI calculated for C₂iH₂₆O₂Si [M+H]⁺, 339.17; found, 339.10.

Step-4:

[1473] To a stirred mixture of NaH (2.38 g, 59.5 mmol, 60% in mineral oil) in THF (100 mL) was added a solution of a 1:1 mixture of (S)-5-((tert-butyldiphenylsilyl)oxy)pent-l-yn-3- ol and (R)-5-((tert-butyldiphenylsilyl)oxy)pent-l-yn-3-ol (28.00 g, 82.71 mmol) in THF (200 mL) dropwise at 0 °C. The mixture was stirred at 0 °C for 30 min, then CH3I (17.61 g, 124.07 mmol) was added dropwise at 0 °C. The resulting solution was stirred room temperature for 3 h. The mixture was quenched with water at 0 °C. The aqueous layer was extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na₂SO4. The resulting mixture was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with PE / EtOAc (5: 1) to afford a 1 : 1 mixture of (S)-tert-butyl((3-methoxypent-4-yn- 1 -yl)oxy)diphenylsilane and (R)-tert-butyl((3- methoxypent-4-yn-l-yl)oxy)diphenylsilane (25 g, 55%) as a yellow oil. MS ESI calculated for C₂₂H₂₈O₂Si [M+H]⁺, 353.19; found, 353. 15.

Step-5:

[1474] To a 1:1 mixture of (S)-tert-butyl((3-methoxypent-4-yn-l-yl)oxy)diphenylsilane and (R)-tert-butyl((3-methoxypent-4-yn-l-yl)oxy)diphenylsilane (25.00 g, 70.91 mmol) was added EtsN (0.72 g, 7.09 mmol), Schwartz's reagent (18.15 g, 141.82 mmol) and HBpin (1.82 g, 7.09 mmol). The mixture was stirred at 60 °C for 2 h under nitrogen atmosphere. The resulting mixture was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with PE I EtOAc (6: 1) to afford a 1 : 1 mixture of (R,E)- tert-butyl((3-methoxy-5-(4,4,5,5-tetramethyl-l,3,2-dioxaborolan-2-yl)pent-4-en-l- yl)oxy)diphenylsilane and (S,E)-tert-butyl((3-methoxy-5-(4,4,5,5-tetramethyl-l,3,2- dioxaborolan-2-yl)pent-4-en-l-yl)oxy)diphenylsilane (20 g, 54%) as a yellow oil. MS ESI calculated for C₂₈H₄iBO₄Si [M+H]⁺, 481.29; found, 481.15. 'H NMR (400 MHz, DMSO-d₆) 57.65 - 7.57 (m, 4H), 7.48 - 7.35 (m, 6H), 6.34 (dd, J= 18.4, 6.4 Hz, 1H), 5.50 (dd, J = 18.0, 0.8 Hz, 1H), 3.86 - 3.79 (m, 1H), 3.76 - 3.60 (m, 2H), 3.13 (s, 3H), 1.78 - 1.65 (m, 2H), 1.21 (s, 12H), 0.99 (s, 9H).

Step-6:

[1475] To a stirred solution of a 1:1 mixture of (R,E)-tert-butyl((3-methoxy-5-(4, 4,5,5- tetramethyl- 1 ,3,2-dioxaborolan-2-yl)pent-4-en- 1 -yl)oxy)diphenylsilane and (S,E)-tert- butyl((3-methoxy-5-(4,4,5,5-tetramethyl-l,3,2-dioxaborolan-2-yl)pent-4-en-l- yl)oxy)diphenylsilane (46.00 g, 95.73 mmol) and 3-bromo-2-chloro-6-

(trifhioromethyl)pyridine (24.93 g, 95.73 mmol) in 1,4-di oxane (460 mL) and H₂O (46 mL) were added K₂CO₂ (39.69 g, 287.18 mmol) and Pd(dppf)Cl₂ (7.00 g, 9.57 mmol). The resulting mixture was stirred at 100 °C for 16 h under nitrogen atmosphere. The resulting mixture was quenched with water. The resulting mixture was extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na₂SO₄. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography with 0-5% EtOAc in PE to afford a 1:1 mixture of (R,E)- 3-(5-((tert-butyldiphenylsilyl)oxy)-3-methoxypent-l-en-l-yl)-2-chloro-6- (trifhioromethyl)pyridine and (S,E)-3-(5-((tert-butyldiphenylsilyl)oxy)-3-methoxypent- 1-en- l-yl)-2-chloro-6-(trifluoromethyl)pyridine (15 g, 95%) as a yellow oil. MS ESI calculated for C28H3iClF₃NO2Si [M+H]⁺, 534.18; found, 534.15.

Step-7:

[1476] To a mixture of B0CNH2 (10.20 g, 87.06 mmol) in n-PrOH (220 mL) was added NaOH (aq, 0.4 M) (190 mL). The mixture was stirred at 0 °C for 10 minutes. DCDMH (7.86 g, 39.88 mmol) was added in portions to the mixture at 0°C. After stirring at 0 °C for 30 minutes, (DHQ)2PHAL (supplier: Shanghai Accela ChemBio Co., Ltd. CAS# 140924-50-1) (2.19 g, 2.81 mmol), a solution of methyl 3-[(lE)-5-[(tert-butyldiphenylsilyl)oxy]-3- methoxypent-l-en-l-yl]-2-chloro-6-(trifluoromethyl)pyridine (15 g, 28.09 mmol) in n- PrOH(50 mL) and K2OSO42H2O (0.89 g, 2.42 mmol) were added to above mixture at 0 °C. The resulting mixture was stirred at 25 °C for 16 h. The reaction mixture was quenched with water. The aqueous layer was extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SO4. The resulting mixture was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with PE / EtOAc (5:1) to afford a 1:1 mixture of tert-butyl ((lS*,2R*,3R)-5-((tert- butyldiphenylsilyl)oxy)-l-(2-chloro-6-(trifluoromethyl)pyridin-3-yl)-2-hydroxy-3- methoxypentyl)carbamate and tert-butyl ((lS*,2R*,3S)-5-((tert-butyldiphenylsilyl)oxy)-l-(2- chloro-6-(trifhioromethyl)pyridin-3-yl)-2-hydroxy-3-methoxypentyl)carbamate (17.00 g, 67%) as a yellow oil. MS ESI calculated for C33H42ClF3N2OsSi [M+H]⁺, 667.20; found, 667.15.

Step-8:

[1477] To a stirred solution of a 1:1 mixture of tert-butyl ((lS*,2R*,3R)-5-((tert- butyldiphenylsilyl)oxy)-l-(2-chloro-6-(trifluoromethyl)pyridin-3-yl)-2-hydroxy-3- methoxypentyl)carbamate and tert-butyl ((lS*,2R*,3S)-5-((tert-butyldiphenylsilyl)oxy)-l-(2- chloro-6-(trifhioromethyl)pyridin-3-yl)-2-hydroxy-3-methoxypentyl)carbamate (7.00 g, 10.49 mmol) in toluene (70 mL) were added CS2CO3 (10.25 g, 31.47 mmol), JohnPhos (0.31 g, 1.05 mmol) and Pd(OAc)2 (0.24 g, 1.05 mmol). The resulting solution was stirred at 100 °C for 18 h under hydrogen atmosphere. The mixture was allowed to cool down to room temperature. The mixture was quenched with water. The aqueous layer was extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SO4. The resulting mixture was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with PE/EtOAc (5:1) to afford a 1:1 mixture of tert-butyl ((2R*,3S*)-2-((R)-3-((tert-butyldiphenylsilyl)oxy)-l-methoxypropyl)-6-(trifluoromethyl)- 2,3-dihydrofuro[2,3-b]pyridin-3-yl)carbamate and tert-butyl ((2R*,3S*)-2-((S)-3-((tert- butyldiphenylsilyl)oxy)-l-methoxypropyl)-6-(trifluoromethyl)-2,3-dihydrofuro[2,3- b]pyridin-3-yl)carbamate (3.3 g, 66%) as a yellow oil. MS ESI calculated for C33H₄iF₃N2O5Si [M+H]⁺, 631.27; found, 631.15.

Step-9:

[1478] To a stirred solution of a 1:1 mixture of tert-butyl ((2R*,3S*)-2-((R)-3-((tert- butyldiphenylsilyl)oxy)-l-methoxypropyl)-6-(trifluoromethyl)-2,3-dihydrofuro[2,3- b]pyridin-3-yl)carbamate and tert-butyl ((2R*,3S*)-2-((S)-3-((tert-butyldiphenylsilyl)oxy)-l- methoxypropyl)-6-(trifluoromethyl)-2,3-dihydrofuro[2,3-b]pyridin-3-yl)carbamate (3.40 g, 5.39 mmol) in THF (35 mL) was added TBAF (3.52 g, 13.48 mmol) at 0 °C. The resulting solution was stirred at room temperature for 2 h. The mixture was quenched with water. The aqueous layer was extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous NaiSCX The resulting mixture was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with PE / EtOAc (5:1) to afford a 1:1 mixture of tert-butyl ((2R*,3S*)-2-((R)-3-hydroxy-l- methoxypropyl)-6-(trifluoromethyl)-2,3-dihydrofuro[2,3-b]pyridin-3-yl)carbamate and tertbutyl ((2R*,3S*)-2-((S)-3-hydroxy-l-methoxypropyl)-6-(trifluoromethyl)-2,3- dihydrofuro[2,3-b]pyridin-3-yl)carbamate (1.6 g, 64%) as a yellow oil. MS ESI calculated for C17H23F3N2O5 [M+H]⁺, 393.16; found, 393.15.

Step- 10: [1479] To a stirred solution of a 1:1 mixture of tert-butyl ((2R*,3S*)-2-((R)-3-hydroxy-l- methoxypropyl)-6-(trifluoromethyl)-2,3-dihydrofuro[2,3-b]pyridin-3-yl)carbamate and tertbutyl ((2R*,3S*)-2-((S)-3-hydroxy-l-methoxypropyl)-6-(trifluoromethyl)-2,3- dihydrofuro[2,3-b]pyridin-3-yl)carbamate (1.6 g, 4.08 mmol) in toluene (160 mL) was added 2-(tributyl-A,⁵-phosphaneylidene)acetonitrile (CAS No. 157141-27-0) (1.97 g, 8.16 mmol). The resulting solution was stirred at 110 °C for 18 h under nitrogen atmosphere. The resulting mixture was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with PE / EtOAc (8:1). And then purified by prep-chiral HPLC with the following conditions: [Column: CHIRAL ART Cellulose-SC, 2*25 cm, 5 pm; Mobile Phase A: Hex (0.5% 2 M NH₃-MeOH)-HPLC, Mobile Phase B: MeOH: DCM=1:1- HPLC; Flow rate: 20 mL/min; Gradient (B%): isocratic 10% B to 10% in lOmin; Wave Length: 220/254 nm; RTl(min): 6.02; RT2(min): 7.31; Sample Solvent: MeOH:DCM=l:l- HPLC] afford rel-tert-butyl (4R,4aR,9bS)-4-methoxy-7-(trifluoromethyl)-3,4,4a,9b- tetrahydrofuro[2,3-b:4,5-b']dipyridine-l(2H)-carboxylate, isomer 1 (150 mg, 93%) as a white solid with retention time at 6.02 minutes. MS ESI) calculated for C17H21F3N2O4 [M+H]⁺, 375.15; found, 375.20. 'H NMR (400 MHz, DMSO-</₆) 5 7.74 (d, 7 = 7.2 Hz, 1H), 7.48 (d, J = 7.6 Hz, 1H), 6.00 (d, J = 9.6 Hz, 1H), 4.90 (dd, 7= 9.6, 6.4 Hz, 1H), 4.01 - 3.76 (m, 1H), 3.47 - 3.37 (m, 1H), 3.35 (s, 3H), 2.89 - 2.62 (m, 1H), 1.92 - 1.76 (m, 1H), 1.56 - 1.39 (s, 10H). Relative stereochemistry was determined by NOESY.

[1480] The chiral resolution also afford rel-tert-butyl (4S,4aR,9bS)-4-methoxy-7- (trifluoromethyl)-3,4,4a,9b-tetrahydrofuro[2,3-b:4,5-b']dipyridine-l(2H)-carboxylate, isomer 2 (330 mg, 97%) as a white solid with retention time at 7.31 minutes. MS ESI calculated for C17H21F3N2O4 [M+H]⁺, 375.15; found, 375.15. ’H NMR (400 MHz, DMSO-J₆) 87.74 (d, J = 7.2 Hz, 1H), 7.44 (d, J = 7.6 Hz, 1H), 6.00 (d, J= 9.2 Hz, 1H), 5.26 (dd, J = 9.2, 3.2 Hz, 1H), 3.76 - 3.65 (m, 2H), 3.29 (s, 3H), 2.85 - 2.64 (m, 1H), 1.96 - 1.84 (m, 1H), 1.69 - 1.57 (m, 1H), 1.47 (s, 9H). Relative stereochemistry was determined by NOESY.

Step-11:

A81, isomer 1

[1481] A stirred solution of rel-tert-butyl (4R,4aR,9bS)-4-methoxy-7-(trifluoromethyl)- 3,4,4a,9b-tetrahydrofuro[2,3-b:4,5-b']dipyridine-l(2H)-carboxylate (150 mg, 0.40 mmol) and HC1 (4M in 1,4-dioxane) (2 mL) was stirred at 0 °C for 3 h. The resulting mixture was concentrated under reduced pressure to afford rel-(4R,4aR,9bS)-4-methoxy-7- (trifluoromethyl)-l,2,3,4,4a,9b-hexahydrofuro[2,3-b:4,5-b']dipyridine hydrochloride, isomer 1 (A81 isomer 1) (100 mg, crude) as a white solid. MS ESI calculated for C11H10F4N2O [M+H]⁺, 263.07; found, 263.20. 'H NMR (400 MHz, DMSO-7₆) 8 10.81 (br, 1H), 9.29 (br, 1H), 8.31 (d, 7 = 7.2 Hz, 1H), 7.63 (d, 7 = 7.2 Hz, 1H), 5.11 (d, 7 = 6.4 Hz, 1H), 4.94 - 4.89 (m, 1H), 3.96 - 3.89 (m, 1H), 3.15 - 3.04 (m, 2H), 2.03 - 1.93 (m, 2H).

Step- 12:

A81 , isomer 2

[1482] A stirred solution of rel-tert-butyl (4S,4aR,9bS)-4-methoxy-7-(trifluoromethyl)- 3,4,4a,9b-tetrahydrofuro[2,3-b:4,5-b']dipyridine-l(2H)-carboxylate (330 mg, 0.88 mmol) and HC1 (4M in 1,4-dioxane) (4 mL) was stirred at 0 °C for 3 h. The resulting mixture was concentrated under reduced pressure to afford rel-(4S,4aR,9bS)-4-methoxy-7- (trifhioromethyl)-l,2,3,4,4a,9b-hexahydrofuro[2,3-b:4,5-b']dipyridine hydrochloride, isomer 2 (A81 isomer 2) (200 mg, crude) as a white solid. MS ESI calculated for C12H13F3N2O2 [M+H]⁺, 275.09; found, 275.15. 'H NMR (400 MHz, DMSO-7₆) 8 11.06 (br, 1H), 8.84 (br, 1H), 8.27 (d, 7 = 7.6 Hz, 1H), 7.62 (d, 7 = 7.6 Hz, 1H), 5.19 - 5.09 (m, 2H), 3.98 - 3.91 (m, 1H), 3.40 (s, 3H), 3.23 - 3.15 (m, 1H), 3.09 - 2.98 (m, 1H), 2.08 - 1.98 (m, 1H), 1.88 - 1.75 (m, 1H). Absolute stereochemistry was not determined. Intermediate A82: rel-(2R,4aS,9bS)-2-methyl-7-(trifluoromethyl)-l,2,3,4,4a,9b- hexahydrofuro[2,3-b:4,5-b']dipyridine

Step-1:

[1483] To a stirred solution of 3-bromo-2-chloro-6-(trifluoromethyl)pyridine (30.0 g, 115.19 mmol) and hex-5-en-2-one (13.5 g, 138.22 mmol), AcOK (33.9 g, 345.57 mmol) and TB AC (3.2 g, 11.51 mmol) in DMF (300 mL) was added Pd(OAc)₂ (2.6 g, 11.51 mmol). The resulting mixture was stirred at 80 °C for 16 h under nitrogen atmosphere. The resulting mixture was filtered, the filter cake was washed with ethyl acetate. The filtrate was quenched with water and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous Na₂SO4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by flash column chromatography with 0 - 10% ethyl acetate in petroleum ether to afford (E)-6-(2-chloro-6- (trifluoromethyl)pyridin-3-yl)hex-5-en-2-one (15.0 g, 46%) as a brown oil. MS ESI calculated for CI₂HHC1F₃NO [M+H]⁺, 278.05; found, 278.00.

Step-2: [1484] To a stirred solution of tert-butyl carbamate (18.3 g, 156.30 mmol) in propan-l-ol (194 mL) was slowly added NaOH (aq., 0.4 M) (168 mL) at 0 °C. The mixture was stirred at 0 °C for 10 min., then DCDMH (14.9 g, 75.63 mmol) was added at room temperature. After stirring at room temperature for 30 min., this was followed by the addiotn of a solution of (DHQ)2-PHAL (supplier: Shanghai Accela ChemBio Co., Ltd. CAS# 140924-50-1) (3.9 g, 5.04 mmol) in propan-l-ol (1 mL) and a solution of (E)-6-(2-chloro-6- (trifhioromethyl)pyridin-3-yl)hex-5-en-2-one (14.0 g, 50.42 mmol) in propan-l-ol (100 mL) dropwise at 0 °C, after that, Potassium osmate(VI) dihydrate (1.8 g, 5.04 mmol) was added. The resulting mixture was stirred at room temperature overnight. The reaction was quenched with water and extracted with ethyl acetate. The organic layers were dried over anhydrous sodium sulfate, filtered and concentrated. The residue was purified by flash column chromatography with 0-60% ethyl acetate in petroleum ether to afford rel-tert-butyl ((1S,2S)- l-(2-chloro-6-(trifluoromethyl)pyridin-3-yl)-2-hydroxy-5-oxohexyl)carbamate (8.3 g, 40%) as a yellow solid. MS ESI calculated for C17H22CIF3N2O4 [M+l]⁺, 411.12; found, 411.00.

Step-3:

[1485] To a stirred solution of rel-tert-butyl ((lS,2S)-l-(2-chloro-6- (trifhioromethyl)pyridin-3-yl)-2-hydroxy-5-oxohexyl)carbamate (9.0 g, 21.90 mmol) in DCM (90 mL) was added TFA (30 mL) at room temperature. The resulting mixture was stirred at room temperature for 1 h. The resulting mixture was concentrated under vacuum. The residue was basified with NaHCCh (sat.) and extracted with dichloromethane. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under vacuum.

[1486] The above residue was dissolved in iPrOH (50 mL), then Pd/C (1.0 g, 10% active on carbon). The mixture was hydrogenated at room temperature for 16 h under hydrogen atmosphere. The resulting mixture was filtered, the filter cake was washed with iPrOH. The filtrate was collected and concentrated under vacuum to afford rel-(2R,3R,6S)-2-(2-chloro-6- (trifhioromethyl)pyridin-3-yl)-6-methylpiperidin-3-ol (4.6 g, crude) as a brown solid. MS ESI calculated for C12H14CIF3N2O [M+H]⁺, 295.07; found, 295.00.

Step-4

[1487] To a solution of rel-(2R,3R,6S)-2-(2-chloro-6-(trifluoromethyl)pyridin-3-yl)-6- methylpiperidin-3-ol (4.6 g, 15.27 mmol) in toluene (90 mL) was added NaH (60%) (0.7 g, 17.50 mmol) at room temperature. The mixture was stirred at 80 °C for 8 h. The reaction mixture was quenched by the addition of water at 0 °C. The mixture was quenched with water and extracted with ethyl acetate. The organic layers were dried over anhydrous sodium sulfate, filtered and concentrated. The residue was purified by reverse phase flash column chromatography with 5-80% acetonitrile in water to afford rel-(2R,4aS,9bS)-2-methyl-7- (trifluoromethyl)-l,2,3,4,4a,9b-hexahydrofuro[2,3-b:4,5-b']dipyridine (A82) (1.8 g, 45%) as a yellow solid. MS ESI calculated for C12H13F3N2O [M+H]⁺, 259.10; found, 259.05. 'H NMR (300 MHz, DMSO-d₆) 57.89 (d, J = 7.2 Hz, 1H), 7.39 (d, J = 7.2 Hz, 1H), 4.55 - 4.51 (m, 1H), 4.24 (d, J = 4.8 Hz, 1H), 2.66 - 2.56 (m, 1H), 2.34 - 2.18 (m, 1H), 2.12 (br, 1H), 1.96 - 1.90 (m, 1H), 1.54 - 1.56 (m, 1H), 1.32 - 1.03 (m, 1H), 0.94 (d, J = 6.3 Hz, 3H). Cis Relative stereochemistry was determined by NOESY. Absolute stereochemistry was not determined.

Intermediate A83 isomer 1: rel-(4R,4aR,10bR)-8-chloro-4-methyl-2,3,4,4a,6,10b- hexahydro-lH-pyrano[3,2-b:5,4-b']dipyridine isomer 1

A83 isomer 1 _anj

Intermediate A83 isomer 2: rel-(4R,4aR,10bR)-8-chloro-4-methyl-2,3,4,4a,6,10b- hexahydro-lH-pyrano[3,2-b:5,4-b']dipyridine isomer 2

A83 isomer 2

Step-1:

[1488] To a stirred solution of 3-bromo-6-chloropicolinic acid (25.0 g, 105.73 mmol) and K2CO3 (29.2 g, 211.46 mmol) in DMF (200 mL) was added Mel (16.5 g, 116.30 mmol) at 0 °C. The resulting mixture was stirred at room temperature for 5 h. The resulting mixture was filtered, the filter cake was washed with ethyl acetate. The filtrate was quenched with water and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous NaiSCX The resulting mixture was concentrated under reduced pressure to afford methyl 3-bromo-6-chloropicolinate (26.0 g, crude) as a yellow solid. MS ESI calculated for C7H₅BrClNO2)[M+H]⁺, 249.92, 251.92; found, 249.90, 251.90.

Step-2:

[1489] To a stirred solution of methyl 3-bromo-6-chloropicolinate (25.0 g, 99.80 mmol) and K2CO3 (41.3 g, 299.42 mmol) in dioxane (300 mL) and H2O (30 mL) were added 1:1 mixture of (S,E)-tert-butyl((3-methyl-5-(4,4,5,5-tetramethyl-l,3,2-dioxaborolan-2-yl)pent-4- en-l-yl)oxy)diphenylsilane and (R,E)-tert-butyl((3-methyl-5-(4,4,5,5-tetramethyl-l,3,2- dioxaborolan-2-yl)pent-4-en-l-yl)oxy)diphenylsilane (51 .0 g, 109.78 mmol) and Pd(dppf)C12-CH2C12 (8.1 g, 9.98 mmol). The resulting mixture was stirred at 80 °C for 8 h under nitrogen atmosphere. The resulting mixture was filtered, the filter cake was washed with ethyl acetate. The filtrate was quenched with water and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous Na2SO4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by flash column chromatography with 0-50% ethyl acetate in petroleum ether to afford a 1:1 mixture of methyl (S,E)-3-(5-((tert-butyldiphenylsilyl)oxy)-3-methylpent-l-en-l-yl)-6- chloropicolinate and methyl (R,E)-3-(5-((tert-butyldiphenylsilyl)oxy)-3-methylpent-l-en-l- yl)-6-chloropicolinate (44.0 g, 75%) as a yellow oil. MS ESI calculated for C29H34ClNC>3Si [M+H]⁺, 508.20; found, 508.25.

Step-3:

[1490] To a solution of tert-butyl carbamate (30.43 g, 259.77 mmol) in propan-l-ol (59.5 mL) and H2O (59.5 mL) was added NaOH (9.35 g, 233.79 mmol) at room temperature. After stirring for 5 minutes, DCDMH (25.59 g, 129.88 mmol) was added in portions at 0 °C, and then the mixture was stirred at 0 °C for additional 30 min. This was followed by the addition of (DHQ)2PHAL (supplier: Shanghai Accela ChemBio Co., Ltd. CAS# 140924-50-1) (6.75 g, 8.65 mmol), Potassium osmate(VI) dihydrate (3.19 g, 8.65 mmol) and 1:1 mixture of methyl (S,E)-3-(5-((tert-butyldiphenylsilyl)oxy)-3-methylpent-l-en-l-yl)-6-chloropicolinate and methyl (R,E)-3-(5-((tert-butyldiphenylsilyl)oxy)-3-methylpent-l-en-l-yl)-6-chloropicolinate (44 g, 86.59 mmol) at room temperature. The mixture was stirred at room temperature for 16 h. The reaction mixture was extracted with EtOAc. The combined organic layers were washed with H2O, then dried over anhydrous Na2SC>4. After filtration, the filtrate was concentrated under reduced pressure. The residue was dissolved in DCM (300 mL), then DCC (35.7 g, 173.23 mmol) and DMAP (2 g, 16.26 mmol) were added at 0 °C. The mixture was stirred at room temperature for 6 h. The mixture was concentrated under vacuum. The residue was purified by silica gel column chromatography, eluted with PE / EtOAv (1:1) to afford a 1:1 mixture of tert-butyl ((5R*,6R*)-6-((S)-4-((tert-butyldiphenylsilyl)oxy)butan-2- yl)-2-chloro-8-oxo-5,8-dihydro-6H-pyrano[3,4-b]pyridin-5-yl)carbamate and tert-butyl ((5R*,6R*)-6-((R)-4-((tert-butyldiphenylsilyl)oxy)butan-2-yl)-2-chloro-8-oxo-5,8-dihydro- 6H-pyrano[3,4-b]pyridin-5-yl)carbamate (22 g, 41% yield) as a yellow oil. MS ESI calculated for CsslLiCl zOsSi [M+H]⁺, 609.25; found, 609.20.

Step-4:

[1491] To a stirred solution of 1 : 1 mixture of tert-butyl ((5R*,6R*)-6-((S)-4-((tert- butyldiphenylsilyl)oxy)butan-2-yl)-2-chloro-8-oxo-5,8-dihydro-6H-pyrano[3,4-b]pyridin-5- yl)carbamate and tert-butyl ((5R*,6R*)-6-((R)-4-((tert-butyldiphenylsilyl)oxy)butan-2-yl)-2- chloro-8-oxo-5,8-dihydro-6H-pyrano[3,4-b]pyridin-5-yl)carbamate (22.0 g, 36.11 mmol) in THF (440 mL) was added NaBtU (5.4 g, 144.44 mmol) in portions at 0 °C. The resulting mixture was stirred at room temperature for 4 h. The reaction was quenched by ice water and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered and concentrated under vacuum. The residue was purified by flash column chromatography with 0-100% ethyl acetate in petroleum ether to afford a 1 :1 mixture of tert-butyl ((lR*,2R*,3S)-5-((tert-butyldiphenylsilyl)oxy)-l-(6-chloro-2- (hydroxymethyl)pyridin-3-yl)-2-hydroxy-3-methylpentyl)carbamate and tert-butyl ((lR*,2R*,3S)-5-((tert-butyldiphenylsilyl)oxy)-l-(6-chloro-2-(hydroxymethyl)pyridin-3-yl)- 2-hydroxy-3-methylpentyl)carbamate (8.0 g, 95%) as a white solid. MS ESI calculated for C₃3H45ClN₂O5Si [M+H]⁺, 613.28; found, 613.30.

Step-5:

[1492] To a stirred solution of 1: 1 mixture of tert-butyl ((lR*,2R*,3S)-5-((tert- butyldiphenylsilyl)oxy)-l-(6-chloro-2-(hydroxymethyl)pyridin-3-yl)-2-hydroxy-3- methylpentyl)carbamate and tert-butyl ((lR*,2R*,3S)-5-((tert-butyldiphenylsilyl)oxy)-l-(6- chloro-2-(hydroxymethyl)pyridin-3-yl)-2-hydroxy-3-methylpentyl)carbamate (8.0 g, 13.05 mmol) in toluene (100 mL) was added 2-(tributyl- ⁵-phosphaneylidene)acetonitrile (CAS No. 157141-27-0) (6.3 g, 26.09 mmol). The resulting mixture was stirred at 110 °C overnight. The mixture was concentrated under vacuum. The residue was purified by flash column chromatography with 0-60% ethyl acetate in petroleum ether to afford a 1:1 mixture of tertbutyl ((5R*,6R*)-6-((S)-4-((tert-butyldiphenylsilyl)oxy)butan-2-yl)-2-chloro-5,8-dihydro- 6H-pyrano[3,4-b]pyridin-5-yl)carbamate and tert-butyl ((5R*,6R*)-6-((R)-4-((tert- butyldiphenylsilyl)oxy)butan-2-yl)-2-chloro-5,8-dihydro-6H-pyrano[3,4-b]pyridin-5- yl)carbamate (3.3 g, 95%) as a yellow oil. MS ESI calculated for C33H43ClN2O4Si [M+H]⁺, 595.27; found, 595.30.

Step-6:

[1493] To a stirred solution of 1: 1 mixture of tert-butyl ((5R*,6R*)-6-((S)-4-((tert- butyldiphenylsilyl)oxy)butan-2-yl)-2-chloro-5,8-dihydro-6H-pyrano[3,4-b]pyridin-5- yl)carbamate and tert-butyl ((5R*,6R*)-6-((R)-4-((tert-butyldiphenylsilyl)oxy)butan-2-yl)-2- chloro-5,8-dihydro-6H-pyrano[3,4-b]pyridin-5-yl)carbamate (3.2 g, 5.46 mmol) in THF (40 mL) was added tetrabutylazanium fluoride (3.4 g, 10.92 mmol) at 0 °C. The resulting mixture was stirred at room temperature for 4 h. The mixture was quenched with water and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered and concentrated under vacuum. The residue was purified by flash column chromatography with 0-80% ethyl acetate in petroleum ether to afford a 1:1 mixture of tert-butyl ((5R*,6R*)-2-chloro-6-((S)-4-hydroxybutan-2-yl)-5,8-dihydro-6H- pyrano[3,4-b]pyridin-5-yl)carbamate and tert-butyl ((5R*,6R*)-2-chloro-6-((R)-4- hydroxybutan-2-yl)-5,8-dihydro-6H-pyrano[3,4-b]pyridin-5-yl)carbamate (2.0 g, 96%) as a yellow oil. MS ESI calculated for C17H25CIN2O4 [M+H]⁺, 357.15; found, 357.15.

Step-7:

isomer 2

[1494] To a stirred solution of 1 : 1 mixture of tert-butyl ((5R*,6R*)-2-chloro-6-((S)-4- hydroxybutan-2-yl)-5,8-dihydro-6H-pyrano[3,4-b]pyridin-5-yl)carbamate and tert-butyl ((5R*,6R*)-2-chloro-6-((R)-4-hydroxybutan-2-yl)-5,8-dihydro-6H-pyrano[3,4-b]pyridin-5- yl)carbamate (1.9 g, 5.46 mmol) in toluene (20 mL) was added 2-(tributyl-A,⁵- phosphaneylidene)acetonitrile (CAS No. 157141-27-0) (2.6 g, 10.92 mmol). The resulting mixture was stirred at 110 °C for 5 h. The resulting mixture was concentrated under vacuum. The residue was purified by flash column chromatography with 0-70% ethyl acetate in petroleum ether to afford crude product. The crude product was separated by Prep-Chiral SFC with the following conditions: [Column: CHIRALPAK IC, 3*25 cm, 5 pm; Mobile Phase A: CO2, Mobile Phase B: IPA (1% 2M NH3-MEOH); Flow rate: 100 mL/min;

Gradient (B%): isocratic 15% B; RTl(min): 4; RT2(min): 6; Sample Solvent: MEOH; Injection Volume: 2 mL; Number Of Runs: 10] to afford rel-tert-butyl (4R,4aR,10bR)-8- chloro-4-methyl-2,3,4,4a,6,10b-hexahydro-lH-pyrano[3,2-b:5,4-b']dipyridine-l-carboxylate isomer 1 (0.4 g, 34%) as a white solid with retention time at 4 minute. MS ESI calculated for C12H15CIN2O [M+H]⁺, 339.14; found, 339.00.

[1495] The chiral resolution also afford rel-tert-butyl (4R,4aR,10bR)-8-chloro-4-methyl- 2,3,4,4a,6,10b-hexahydro-lH-pyrano[3,2-b:5,4-b']dipyridine-l-carboxylate isomer 2 (0.3 g, 23%) as a yellow oil. MS ESI calculated for C12H15CIN2O [M+H]⁺, 339.14; found, 339.00.

Step-8: isomer 1 A83 isomer 1

[1496] A mixture solution of rel-tert-butyl (4R,4aR,10bR)-8-chloro-4-methyl- 2,3,4,4a,6,10b-hexahydro-lH-pyrano[3,2-b:5,4-b']dipyridine-l-carboxylate isomer 1 (100 mg, 0.29 mmol) and HC1 in 1,4-dioxane (3 mL, 4M) was stirred at room temperature for 30 min. The resulting mixture was concentrated under vacuum to afford rel-(4R,4aR,10bR)-8- chloro-4-methyl-2,3,4,4a,6,10b-hexahydro-lH-pyrano[3,2-b:5,4-b']dipyridine hydrochloride isomer 1 (A83 isomer 1) (130 mg, crude) as a white solid. MS ESI calculated for C12H15CIN2O [M+H]⁺, 239.09; found, 239.10.

Step-9:

[1497] A mixture of rel-tert-butyl (4R,4aR,10bR)-8-chloro-4-methyl-2,3,4,4a,6,10b- hexahydro-lH-pyrano[3,2-b:5,4-b']dipyridine-l -carboxylate isomer 2 (230 mg, 0.67 mmol) and HC1 (4.0 M in 1,4-dioxane) (2 mL) was stirred at room temperature for 1 hour. The resulting mixture was concentrated under vacuum to afford rel-(4R,4aR,10bR)-8-chloro-4- methyl-2,3,4,4a,6,10b-hexahydro-lH-pyrano[3,2-b:5,4-b']dipyridine hydrochloride isomer 2 (A83 isomer 2) (190 mg) as a white solid. MS ESI calculated for C12H15CIN2O [M+H]⁺, 239.09; found, 239.10. Absolute stereochemistry was not determined.

Intermediate A84: rel-(4R,4aR,9bR)-7-chloro-4-methyl-l,2,3,4,4a,9b-hexahydrofuro[2,3- b:4,5-b']dipyridine isomer 1 and rel-(4R,4aR,9bR)-7-chloro-4-methyl-l,2,3,4,4a,9b- hexahydrofuro[2,3-b:4,5-b']dipyridine isomer 2

[1498] To a stirred solution of 3-bromo-2,6-dichloropyridine (10 g, 44.07 mmol) and 1:1 mixture of (R,E)-tert-butyl((3-methyl-5-(4,4,5,5-tetramethyl- 1 ,3,2-dioxaborolan-2-yl)pent-4- en-l-yl)oxy)diphenylsilane and (S,E)-tert-butyl((3-methyl-5-(4,4,5,5-tetramethyl-l,3,2- dioxaborolan-2-yl)pent-4-en-l-yl)oxy)diphenylsilane (22.52 g, 48.48 mmol) in dioxane (90 mL) and H2O (18 mL) were added K2CO3 (18.27 g, 132.22 mmol) and Pd(dppf)Ch (3.23 g, 4.40 mmol) at room temperature under nitrogen atmosphere. The resulting mixture was stirred at 100°C for 16 h. The reaction was cooled down to room temperature and quenched with water. The resulting mixture was extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SO4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with PE / EtOAc (5:1) to afford a 1:1 mixture of (R,E)-3-(5-((tert- butyldiphenylsilyl)oxy)-3-methylpent-l-en-l-yl)-2,6-dichloropyridine and (S,E)-3-(5-((tert- butyldiphenylsilyl)oxy)-3-methylpent-l-en-l-yl)-2,6-dichloropyridine (20.6 g, 90%) as a yellow oil. MS ESI calculated for C27H₃iCi2NOSi [M+H]⁺, 484.16; found, 484.15.

Step-2: [1499] To a stirred solution of tert-butyl carbamate (15.44 g, 131.79 mmol) in propan-l-ol (166 mL) was added a solution of NaOH (4.59 g, 114.79 mmol) in H2O (144 mL) at room temperature under nitrogen atmosphere. The resulting mixture was stirred at room temperature for 10 min. Then l,3-dichloro-5,5-dimethylimidazolidine-2, 4-dione (16.75 g, 85.03 mmol) was added in portions at room temperature. After stirring at room temperature for additional 30 minutes, a solution of (DHQ)2PHAL (3.31 g, 4.25 mmol) (supplier: Shanghai Accela ChemBio Co., Ltd. CAS# 140924-50-1) in propan-l-ol (42 mL), a 1:1 mixture of (R,E)-3-(5-((tert-butyldiphenylsilyl)oxy)-3-methylpent-l-en-l-yl)-2,6- dichloropyridine and (S,E)-3-(5-((tert-butyldiphenylsilyl)oxy)-3-methylpent-l-en-l-yl)-2,6- dichloropyridine (20.6 g, 42.51 mmol) in propan-l-ol (42 mL) and a mixture of Potassium osmate(VI) dihydrate (1.57 g, 4.25 mmol) and NaOH (aq., 0.4M) at 0 °C. The resulting mixture was stirred at room temperature for additional 16 h. The resulting mixture was extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SO4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with PE / EtOAc (0-20%) to afford a 1:1 mixture of tert-butyl ((lS*,2S*,3R)-5-((tert-butyldiphenylsilyl)oxy)-l-(2,6- dichloropyridin-3-yl)-2-hydroxy-3-methylpentyl)carbamate and tert-butyl ((lS*,2S*,3S)-5- ((tert-butyldiphenylsilyl)oxy)-l-(2,6-dichloropyridin-3-yl)-2-hydroxy-3- methylpentyl)carbamate (15.3 g, 90%) as a green oil. MS ESI calculated for C32H₄2C12N₂O4Si [M+H]⁺, 617.23; found, 617.20.

Step-3:

[1500] To a stirred solution of 1 : 1 mixture of tert-butyl ((lS*,2S*,3R)-5-((tert- butyldiphenylsilyl)oxy)- 1 -(2,6-dichloropyridin-3-yl)-2-hydroxy-3-methylpentyl)carb- amate and tert-butyl (( 1 S * ,2S * ,3S)-5-((tert-butyldiphenylsilyl)oxy)- 1 -(2,6-dichloropyridin-3-yl)-2- hydroxy-3-methylpentyl)carbamate (18.1 g, 29.30 mmol) in THF (155 mL) was added TBAF (15.32 g, 58.60 mmol) at room temperature under nitrogen atmosphere. The resulting mixture was stirred at room temperature for 16 h. The resulting mixture was concentrated under vacuum. The residue was purified by silica gel column chromatography, eluted with 0-100% to EtOAc in PE afford a 1:1 mixture of tert-butyl ((lS*,2S*,3S)-l-(2,6-dichloropyridin-3-yl)- 2,5-dihydroxy-3-methylpentyl)carbamate and tert-butyl ((lS*,2S*,3R)-l-(2,6- dichloropyridin-3-yl)-2,5-dihydroxy-3-methylpentyl)carbamate (1.5 g, 95%) as a yellow oil.

MS ESI calculated for C16H24C12N2O4 [M+H]⁺, 379.11; found, 379.10.

Step-4:

[1501] To a stirred solution of 1:1 mixture of tert-butyl ((lS*,2S*,3S)-l-(2,6- dichloropyridin-3-yl)-2,5-dihydroxy-3-methylpentyl)carbamate and tert-butyl ((1S*,2S*,3R)- l-(2,6-dichloropyridin-3-yl)-2,5-dihydroxy-3-methylpentyl)carbamate (1.5 g, 3.95 mmol) and TEA (1.20 g, 11.86 mmol) in DCM (15 mL) was added Ms₂O (0.47 g, 4.74 mmol) at 0 °C. The resulting mixture was stirred at room temperature for 16 h. The reaction was quenched with ice water and extracted with CH2CI2. The combined organic layers were washed with brine, dried over anhydrous NaiSCL. After filtration, the filtrate was concentrated under reduced pressure. The resulting mixture was concentrated under vacuum. The residue was dissolved in DCM (16 mL), then TFA (10 mL) was added at room temperature. The resulting mixture was stirred at room temperature for 1 h. The resulting mixture was concentrated under vacuum. The residue was dissloved in ACN (28 mL), this was followed by the addition of 1,2,2,6,6-pentamethylpiperidine (9.74 g, 62.70 mmol) at room temperature under nitrogen atmosphere. The resulting mixture was stirred at 50 °C for 16 h. The mixture was concentrated under vacuum. The resulting residue was purified by reverse phase flash column chromatography with an 80 g C18 column eluted with 5-100% acetonitrile in water (10 mmol/L NH4HCO3) to afford a 1:6 mixture of rel-(2S,3S,4S)-2-(2,6-dichloropyridin-3-yl)-4- methylpiperidin-3-ol isomer 1 and rel-(2S,3S,4R)-2-(2,6-dichloropyridin-3-yl)-4- methylpiperidin-3-ol isomer 2 (217 mg, 95%) as a yellow oil. MS ESI calculated for C11H14C12N2O [M+H]⁺, 261.05; found, 261.05.

Step-5:

[1502] To a stirred solution of 1:6 mixture of rel-(2S,3S,4S)-2-(2,6-dichloropyridin-3-yl)- 4-methylpiperidin-3-ol isomer 1 and rel-(2S,3S,4R)-2-(2,6-dichloropyridin-3-yl)-4- methylpiperidin-3-ol isomer 2 (207 mg, 0.79 mmol) in MeOH (2 mL) was added BoczO (259 mg, 1.19 mmol) at room temperature under nitrogen atmosphere. The resulting mixture was stirred at room temperature for 16 h. The resulting mixture was concentrated under vacuum. The residue was purified by silica gel column chromatography, eluted with PE / EtOAc (0- 30%) to afford a 1:6 mixture of rel-tert-butyl (2S,3S,4S)-2-(2,6-dichloropyridin-3-yl)-3- hydroxy-4-methylpiperidine-l -carboxylate isomer 1 and rel-tert-butyl (2S,3S,4R)-2-(2,6- dichloropyridin-3-yl)-3-hydroxy-4-methylpiperidine-l-carboxylate isomer 2 (199 mg, 98%) as a colorless oil. MS ESI calculated for C16H22C12N2O3 [M+H]⁺, 361.10; found, 361.10.

Step-6:

[1503] To a stirred solution of 1 :6 mixture of rel-tert-butyl (2S,3S,4S)-2-(2,6- dichloropyridin-3-yl)-3-hydroxy-4-methylpiperidine-l -carboxylate isomer 1 and rel-tert-butyl (2S,3S,4R)-2-(2,6-dichloropyridin-3-yl)-3-hydroxy-4-methylpiperidine- 1 -carboxylate isomer 2 (179 mg, 0.49 mmol) in tert-Amyl alcohol (10 mL) was added t-BuOK (111 mg, 0.99 mmol) at room temperature under nitrogen atmosphere. The resulting mixture was stirred at 60 °C for 16 h. The resulting mixture cooled down to room temperature and quenched with water. The mixture was extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SC>4. After filtration, the filtrate was concentrated under reduced pressure. The resulting mixture was concentrated under vacuum to afford a 1:6 mixture of rel-tert-butyl (4S,4aS,9bS)-7-chloro-4-methyl-3,4,4a,9b-tetrahydrofuro[2,3-b:4,5- b']dipyridine-l(2H)-carboxylate isomer 1 and rel-tert-butyl (4R,4aS,9bS)-7-chloro-4-methyl- 3,4,4a,9b-tetrahydrofuro[2,3-b:4,5-b']dipyridine-l(2H)-carboxylate isomer 2 (crude, 124 mg) as a white solid. MS ESI calculated for C16H21CIN2O3 [M+H]⁺, 325.12; found, 325.10.

Step-7:

A84

[1504] A mixture of 1:6 mixture of rel-tert-butyl (4S,4aS,9bS)-7-chloro-4-methyl- 3,4,4a,9b-tetrahydrofuro[2,3-b:4,5-b']dipyridine-l(2H)-carboxylate isomer 1 and rel-tert- butyl (4R,4aS,9bS)-7-chloro-4-methyl-3,4,4a,9b-tetrahydrofuro[2,3-b:4,5-b']dipyridine- l(2H)-carboxylate isomer 2 (114 mg, 0.35 mmol) and HC1 in dioxane (2 mL, 4M) was stirred at room temperature for 16 h. The resulting mixture was concentrated under vacuum to afford a 1 :6 mixture of rel-(4S,4aS,9bS)-7-chloro-4-methyl-l ,2,3,4,4a,9b-hexahydrofuro[2,3-b:4,5- b']dipyridine hydrochloride isomer 1 and rel-(4R,4aS,9bS)-7-chloro-4-methyl-l,2,3,4,4a,9b- hexahydrofuro[2,3-b:4,5-b']dipyridine isomer 2 hydrochloride (A84) (crude, 94 mg) as a white solid. MS ESI calculated for C11H13CIN2O [M+H]⁺, 225.07; found, 225.10.

Intermediate A85: (2R,4aS,10bS)-2-methyl-8-(prop-2-yn-l-yloxy)-l,2,3,4a,5,10b- hexahydrochromeno[3,4-b] [ 1 ,4]oxazine

A85

Step-1: [1505] A solution of 7-bromochroman-4-one (10 g, 44.04 mmol) and CuBr2 (19.67 g, 88.08 mmol) in EtOAc (100 mL) was stirred at 80 °C for 2 h under nitrogen atmosphere. The mixture was filtered. The filtrate was concentrated under vacuum. The resulting residue was purified by normal phase flash column chromatography with 0-20% ethyl acetate in petroleum ether to afford a 1:1 mixture of (S)-3,7-dibromochroman-4-one and (R)-3,7- dibromochroman-4-one (12.6 g, 86%) as a white solid. MS ESI calculated for CgHgBnCh [M+H]⁺, 304.87, 306.87; found, 304.95, 304.95.

Step-2:

[1506] To a solution of 1:1 mixture of (S)-3,7-dibromochroman-4-one and (R)-3,7- dibromochroman-4-one (25.3 g, 82.69 mmol) in EtOH (250 mL) was added NaBJU (3.13 g, 82.69 mmol) in porstions at 0 °C. The mixture was stirred at 25 °C for 2 h under nitrogen atmosphere. The reaction was quenched by water and extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SC>4. After filtration, the filtrate was concentrated under reduced pressure to afford a 1:1 mixture of (3R,4S)-3,7- dibromochroman-4-ol and (3S,4R)-3,7-dibromochroman-4-ol (28 g, crude) as a white solid. ^XH NMR (300 MHz, DMSO-dg) 57.26 (d, J = 9.0 Hz, 1H), 7.13 - 7.02 (m, 1H), 7.00 - 6.95 (m, 1H), 6.04 (s, 1H), 4.84 (d, J = 6.0 Hz, 1H), 4.73 - 4.66 (m, 1H), 4.60 - 4.51 (m, 1H), 4.33 (dd, J = 12.0, 6.0 Hz, 1H).

Step-3:

[1507] To a solution of 1: 1 mixture of (3R,4S)-3,7-dibromochroman-4-ol and (3S,4R)-3,7- dibromochroman-4-ol (28 g, 90.91 mmol) in CH3CN (280 mL) was added H2SO4 (17.83 g, 181.83 mmol) dropwise at 0 °C. The resulting mixture was stirred at 50 °C for 1 h. The resulting mixture was concentrated under reduced pressure. The residue was dissolved in H2O (200 mL) and heated at 100 °C for 16 h with stirring. The mixture was cooled and basified by NaOH (30% aq.) to pH 10. The precipitated solids were collected by filtration and washed with water to afford a 1:1 mixture of (3S,4S)-4-amino-7-bromochroman-3-ol and (3R,4R)-4-amino-7-bromochroman-3-ol (21 g, 69%) as a white solid. MS ESI calculated for C₉HioBrN0₂ [M+H]⁺, 243.99, 245.99; found, 244.15, 246.10.

Step-4:

[1508] To a solution of a 1:1 mixture of (3S,4S)-4-amino-7-bromochroman-3-ol and (3R,4R)-4-amino-7-bromochroman-3-ol (14 g, 57.36 mmol,) in MeOH (140 mL) were added TEA (17.46 g, 172.07 mmol) and BOC2O (13.77 g, 63.09 mmol). The resulting mixture was stirred at room temperature for 2 h. The resulting mixture was concentrated under vacuum. The residue was purified by silica gel column chromatography, eluted with PE / EtOAc (2:1) to afford a 1:1 mixture of tert-butyl ((3S,4S)-7-bromo-3-hydroxychroman-4-yl)carbamate and tert-butyl ((3R,4R)-7-bromo-3-hydroxychroman-4-yl)carbamate (14.30 g, 71%) as an off- white solid. MS ESI calculated for Ci₄Hi₈BrNO₄ [M+H]⁺, 344.04, 346.04; found, 344.05, 346.05.

Step-5:

[1509] To a solution of a 4:3 mixture of tert-butyl ((3S,4S)-7-bromo-3-hydroxychroman-4- yl)carbamate and tert-butyl ((3R,4R)-7-bromo-3-hydroxychroman-4-yl)carbamate (14.30 g, 41.55 mmol) in DCM (143 mL) were sequentially added (Bu₄N)HSO₄ (2.82 g, 8.31 mmol), NaOH (11.63 g, 290.82 mmol) and (S)-4-methyl-l,3,2-dioxathiolane 2,2-dioxide (7.46 g, 54.01 mmol) (supplier: Suzhou spark Biotechnology Co., Ltd. CAS# 174953-30-1). The resulting mixture was stirred at room temperature for 1 h. The resulting mixture was concentrated under vacuum. The residue was dissolved in H2O (29 mL), and H2SO4 (214 mL) was added at 0 °C with stirring. The resulting mixture was stirred at 80 °C for 16 h. The mixture was cooled and basified with NaOH (aq.) to pH 8. The resulting mixture was extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SO4. After filtration, the filtrate was concentrated under reduced pressure to afford a 1:1 mixture of (S)-l-(((3S,4S)-4-amino-7-bromochroman-3-yl)oxy)propan-2-ol and (S)-l-(((3R,4R)-4-amino-7-bromochroman-3-yl)oxy)propan-2-ol (14.3 g, crude) as a brown solid. MS ESI calculated for Ci2Hi₆BrNO₃ [M+H]⁺, 302.03, 304.03; found, 302.00, 304.00.

Step-6:

[1510] To a solution of a 1:1 mixture of (S)-l-(((3S,4S)-4-amino-7-bromochroman-3- yl)oxy)propan-2-ol and (S)-l-(((3R,4R)-4-amino-7-bromochroman-3-yl)oxy)propan-2-ol in methanol (89 mL) were added TEA (8.89 g, 87.86 mmol) and BOC2O (7.03 g, 32.22 mmol). The resulting mixture was stirred at room temperature for 1 h. The resulting mixture was concentrated under vacuum. The residue was purified by silica gel column chromatography, eluted with PE / EtOAc (1:2) to afford a 1:1 mixture of tert-butyl ((3S,4S)-7-bromo-3-((S)-2- hydroxypropoxy)chroman-4-yl)carbamate and tert-butyl ((3R,4R)-7-bromo-3-((S)-2- hydroxypropoxy)chroman-4-yl)carbamate (8.1 g, 68%) as a white solid. MS ESI calculated for (Ci₇H24BrNO₅) [M+H]⁺, 402.08, 404.08; found, 402.00, 404.05.

Step-7:

[1511] To a solution of a 1:1 mixture of tert-butyl ((3S,4S)-7-bromo-3-((S)-2- hydroxypropoxy)chroman-4-yl)carbamate and tert-butyl ((3R,4R)-7-bromo-3-((S)-2- hydroxypropoxy)chroman-4-yl)carbamate (8.1 g, 20.38 mmol) in toluene (82 mL) were added 2-(tributyl-X.⁵-phosphaneylidene)acetonitrile (CAS No. 157141-27-0) (9.27 g, 40.77 mmol). The resulting mixture was stirred at 110 °C for 3 h under nitrogen atmosphere. The resulting mixture was concentrated under vacuum. The residue was purified by silica gel column chromatography, eluted with PE / EtOAc (4:1) to afford tert-butyl (2R,4aR,10bR)-8- bromo-2-methyl-2,3 ,4a, 10b-tetrahydrochromeno[3 ,4-b] [ 1 ,4] oxazine- 1 (5H)-carboxylate (2.63 g, 33%) as a yellow oil as the first eluting peak. MS ESI calculated for Ci?H22BrNO4 [M+H]⁺, 384.07, 386.07; found, 384.25, 386.20. ’H NMR (400 MHz, DMSO) 8 7.43 (d, J = 8.0 Hz, 1H), 6.75 - 6.68 (m, 1H), 6.51 (s, 1H), 4.19 - 4.07 (m, 2H), 3.94 (d, J= 3.2 Hz, 1H), 3.74 - 3.71 (m, 1H), 3.57 (dd, J = 10.8, 3.2 Hz, 1H), 3.07 (t, J = 10.4 Hz, 1H), 2.49 - 2.46 (m, 1H), 2.21 (s, 9H), 0.82 (d, J - 6.4 Hz, 3H). Absolute stereochemistry was determined by NOESY.

[1512] The purification process also afford tert-butyl (2R,4aS,10bS)-8-bromo-2-methyl- 2,3,4a,10b-tetrahydrochromeno[3,4-b][l,4]oxazine-l(5H)-carboxylate (3.67 g, 46%) as a yellow oil with the second peak on flash. MS ESI calculated for CnffeBrNCh [M+H]⁺, 384.07, 386.07; found, 384.25, 386.20. 'H NMR (400 MHz, DMSO) 57.14 (d, J = 7.6 Hz, 1H), 6.70 (dd, J = 7.6, 1.2 Hz, 1H), 6.58 (s, 1H), 4.66 - 4.59 (m, 1H), 3.99 - 3.89 (m, 2H), 3.85 - 3.79 (m, 1H), 3.46 (dd, J = 10.4, 3.2 Hz, 1H), 3.15 (t, J = 10.4 Hz, 1H), 2.99 - 2.88 (m, 1H), 2.21 (s, 9H), 0.87 (d, J - 6.4 Hz, 3H). Absolute stereochemistry was determined by NOESY.

Step 8:

[1513] A solution of tert-butyl (2R,4aS,10bS)-8-bromo-2-methyl-2,3,4a,10b- tetrahydrochromeno[3,4-b][l,4]oxazine-l(5H)-carboxylate (500 mg, 1.3mmol) in DMSO (8 mL) and H2O (2 mL) were added N,N'-bis(4-hydroxy-2,6-dimethylphenyl)ethanediamide (854 mg, 2.6 mmol) and Cu(acac)2 (681 mg, 2.6 mmol) at room temperature, this was followed by the addition of NaOH (104 mg, 2.6 mmol) in portions at room temperature. The resulting mixture was heated to 110 °C with stirring overnight. The reaction was quenched by water and extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SC>4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by flash column chromatography with 0-30% ethyl acetate in petroleum ether to afford tert-butyl (2R,4aS,10bS)-8-hydroxy-2-methyl-2,3,4a,10b- tetrahydrochromeno[3,4-b][l,4]oxazine-l(5H)-carboxylate (450 mg, 95%) as a yellow oil. MS ESI calculated for C17H23NO5 [M+H]⁺, 322.16; found, 322.05.

Step 9:

[1514] To a solution of tert-butyl (2R,4aS,10bS)-8-hydroxy-2-methyl-2,3,4a,10b- tetrahydrochromeno[3,4-b][l,4]oxazine-l(5H)-carboxylate (500 mg, 1.56mmol) in DMF (5 mL) were added K2CO3 (537 mg, 3.89mmol) and propargyl bromide (555 mg, 4.67mmol) at room temperature with stirring. The resulting mixture was stirred at 80 °C for 8 hours under nitrogen atmosphere. The reaction was quenched by water and extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SO4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by flash column chromatography with 0-30% ethyl acetate in petroleum ether to afford tertbutyl (2R,4aS, 10bS)-2-methyl-8-(prop-2-yn- 1 -yloxy)-2,3,4a, 10b-tetrahydrochromeno[3,4- b][ 1,4] oxazine- l(5H)-carboxylate (350 mg, 50%) as a yellow oil. MS ESI calculated for C20H25NO5 [M+H]⁺, 360.17; found, 360.15.

Step 10:

[1515] A mixture of tert-butyl (2R,4aS,10bS)-2-methyl-8-(prop-2-yn-l-yloxy)-2,3,4a,10b- tetrahydrochromeno[3,4-b][l,4]oxazine-l(5H)-carboxylate (300 mg, 0.84 mmol) and HC1 (g) in dioxane (4M, 10 mL) was stirred at room temperature for 2 hours. The resulting mixture was concentrated under reduced pressure to afford (2R,4aS,10bS)-2-methyl-8-(prop-2-yn-l- yloxy)-l,2,3,4a,5,10b-hexahydrochromeno[3,4-b][l,4]oxazine hydrochloride (A85) (240 mg, 76%) as a yellow solid. MS ESI calculated for C15H17NO3 [M+H]⁺, 260.12; found, 260.10.

¹H NMR (300 MHz, DMSO-cfc) 8 10.71 (br, 1H), 9.40 (br, 1H), 7.67 (d, J = 8.6 Hz, 1H), 6.68 (dd, J= 8.6, 2.6 Hz, 1H), 6.52 (d, J= 2.6 Hz, 1H), 4.81 (d, J = 2.4 Hz, 2H), 4.70 (t, J= 10.8 Hz, 1H), 4.57 - 4.55 (m, 1H), 4.47 - 4.40 (m, 1H), 4.19 - 4.14 (m, 1H), 3.85 - 3.82 (m, 1H), 3.57 - 3.51 (m, 3H), 1.20 (d, J = 5.6 Hz, 3H).

Intermediate A86: (2R,4aS,10bS)-8-ethynyl-2-methyl-l,2,3,4a,5,10b- hexahydrochromeno[3,4-b] [ 1 ,4]oxazine

Step 1:

[1516] To a stirred mixture of tert-butyl (2R,4aS,10bS)-8-bromo-2-methyl-2,3,4a,10b- tetrahydrochromeno[3,4-b][l,4]oxazine-l(5H)-carboxylate (500 mg, 1.30 mmol) and trimethylsilylacetylene (639.00 mg, 6.50mmol) were added Pd(PPh3)4 (451.09 mg, 0.39mmol), Cui (247.81 mg, 1.30mmol) and EtsN (25.00 mL, 179.84 mmol) at room temperature. The resulting mixture was stirred at 80 °C overnight under nitrogen atmosphere. The reaction was quenched by water and extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous NaiSCL. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-30% ethyl acetate in petroleum ether to afford tert-butyl (2R,4aS,10bS)-2-methyl-8-((trimethylsilyl)ethynyl)-2,3,4a,10b-tetrahydrochromeno[3,4- b][ 1,4] oxazine- l(5H)-carboxylate (526 mg, 86.5%) as a yellow oil. MS ESI calculated for C22H₃iNO₄Si [M+H]⁺, 402.20 ; found, 402.10.

Step 2:

[1517] To solution of tert-butyl (2R,4aS,10bS)-2-methyl-8-((trimethylsilyl)ethynyl)- 2,3,4a,10b-tetrahydrochromeno[3,4-b][l,4]oxazine-l(5H)-carboxylate (500 mg, 1.25nunol) in methanol (30 mL) was added K2CO3 (516 mg, 3.74mmol) at room temperature. The resulting mixture was stirred at room temperature overnight. The solids were filtered off. The filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-50% ethyl acetate in petroleum ether to afford tertbutyl (2R,4aS,10bS)-8-ethynyl-2-methyl-2,3,4a,10b-tetrahydrochromeno[3,4-b][l,4]oxazine- l(5H)-carboxylate (400 mg, 87%) as a yellow oil. MS ESI calculated for C19H23NO4 [M+H]⁺, 330.16; found, 330.15.

Step 3:

A86

[1518] A mixture of tert-butyl (2R,4aS,10bS)-8-ethynyl-2-methyl-2,3,4a,10b- tetrahydrochromeno[3,4-b][l,4]oxazine-l(5H)-carboxylate (400 mg, 1.21mmol) and HCl (g) in 1,4-dioxane (4.0 M, 30 mL) was stirred at room temperature for 3 h. The resulting mixture was concentrated under reduced pressure. This resulted in (2R,4aS,10bS)-8-ethynyl-2- methyl-l,2,3,4a,5,10b-hexahydrochromeno[3,4-b][l,4]oxazine hydrochloride (A86) (312 mg, 89%) as a yellow solid. MS ESI calculated for C14H15NO2 [M+H]⁺, 230.11; found, 230.10. ¹H NMR (400 MHz, DMSO- fe) 6 10.73 (s, 1H), 9.58 (s, 1H), 7.77 - 7.72 (m, 1H), 7.16 - 7.01 (m, 1H), 7.01 (d, J = 1.8 Hz, 1H), 4.80 - 4.58 (m, 2H), 4.48 - 4.43 (m, 1H), 4.36 - 4.16 (m, 2H), 3.87 - 3.83 (m, 1H), 3.58 - 3.83 (m, 2H), 1.48 - 0.93 (m, 3H).

Intermediate A87: (2R,3R,4aS,9bS)-3-methoxy-2-methyl-7-(trifluoromethyl)-l,2,3,4,4a,9b- hexahydrofuro[2,3-b:4,5-b']dipyridine

A87

Step-1:

[1519] To a stirred solution of (R,E)-tert-butyl((2-methoxy-5-(4,4,5,5-tetramethyl-l,3,2- dioxaborolan-2-yl)pent-4-en-l-yl)oxy)dimethylsilane (10.00 g, 28.06 mmol) and 3-bromo-2- chloro-6-(trifluoromethyl)pyridine (7.31 g, 28.06 mmol) in dioxane (100 mL) and H2O (10 mL) were added K2CO3 (11.63 g, 84.18 mmol) and Pd(dppf)Ch (2.05 g, 2.81 mmol) at room temperature under nitrogen atmosphere. The resulting mixture was stirred at 100 °C for 16 h. The mixture was allowed to cool down to room temperature and quenched with water. The resulting mixture was extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous Na2SO4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-10% EtOAc in PE to afford (R,E)-3-(5-((tert-butyldimethylsilyl)oxy)-4-methoxypent-l-en- l-yl)-2-chloro-6-(trifluoromethyl)pyridine (9.00 g, 78%) as a brown oil. MS ESI calculated for Ci₈H27ClF₃NO2Si [M+H]⁺, 410.15; found, 410.15.

Step-2:

[1520] To a stirred solution of (R,E)-3-(5-((tert-butyldimethylsilyl)oxy)-4-methoxypent-l- en-l-yl)-2-chloro-6-(trifluoromethyl)pyridine (20.60 g, 50.25 mmol) and DMP (31.97 g, 75.38 mmol) in DMSO (200 mL) was added TsOH (0.87 g, 5.03 mmol) at room temperature. The resulting mixture was stirred at 50 °C for 2 h. The mixture was allowed to cool down to room temperature and quenched with water. The resulting mixture was extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous NaiSCM. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-32% EtOAc in PE to afford (R,E)-5-(2- chloro-6-(trifluoromethyl)pyridin-3-yl)-2-methoxypent-4-enal (11.00 g, 74%) as a brown oil.

MS ESI calculated for C12H11CIF3NO2 [M+H]⁺, 294.04; found, 294.05.

Step-3:

[1521] To a stirred solution of (R,E)-5-(2-chloro-6-(trifluoromethyl)pyridin-3-yl)-2- methoxypent-4-enal (11.00 g, 37.46 mmol) and 4A molecular sieve in THF (100 mL) was added MeMgBr (1 M/L in THF) (93 mL, 93.00 mmol) dropwise at -78 °C under nitrogen atmosphere. The resulting mixture was stirred at room temperature for additional 1 h. The reaction was quenched by NH4CI (sat.) at 0 °C and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous NazSCL. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-55% EtOAc in PE to afford a 1:4 mixture of (2R,3R,E)-6-(2-chloro-6-(trifluoromethyl)pyridin-3-yl)-3-methoxyhex-5-en-2-ol and (2S,3R,E)-6-(2-chloro-6-(trifluoromethyl)pyridin-3-yl)-3-methoxyhex-5-en-2-ol (1.87 g, 16%) as a brown oil. MS ESI calculated for C13H15CIF3NO2 [M+H]⁺, 310.07; found, 310.05.

[1522] To a stirred solution of a 1:4 mixture of (2R,3R,E)-6-(2-chloro-6-

(trifhioromethyl)pyridin-3-yl)-3-methoxyhex-5-en-2-ol and (2S,3R,E)-6-(2-chloro-6- (trifhioromethyl)pyridin-3-yl)-3-methoxyhex-5-en-2-ol (1.87 g, 6.13 mmol) and imidazole (1.25 g, 18.41 mmol) in DCM (20 mL) was added TBDPS-C1 (2.53 g, 9.20 mmol) at room temperature under nitrogen atmosphere. The resulting mixture was stirred at room temperature for 16 h. The resulting mixture was quenched with water and extracted with DCM. The combined organic layers were washed with brine, dried over anhydrous Na2SC>4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-20% EtOAc in PE to afford a 1:4 mixture of 3-((4R,5R,E)-5-((tert-butyldiphenylsilyl)oxy)-4-methoxyhex-l-en-l-yl)-2-chloro- 6-(trifluoromethyl)pyridine and 3-((4R,5S,E)-5-((tert-butyldiphenylsilyl)oxy)-4-methoxyhex- l-en-l-yl)-2-chloro-6-(trifluoromethyl)pyridine (2.20 g, 65%) as a colorless oil. MS ESI calculated for C₂9H33ClF₃NO₂Si [M+H]⁺, 548.19; found, 548.15.

Step-5:

[1523] To a stirred solution of B0CNH2 (0.4 M/L in i-PrOH) (39 mL, 12.44 mmol) were sequentially added NaOH (0.4 M, aq.) (28 mL) and DCDMH (1.19 g, 6.02 mmol) at 0 °C. After stirring at 0 °C for 20 min., (DHQ)2PHAL (supplier: Shanghai Accela ChemBio Co., Ltd. CAS# 140924-50-1) (0.1 M/L in i-PrOH) (39 mL, 0.15 mmol), a 1:4 mixture of 3- ((4R,5R,E)-5-((tert-butyldiphenylsilyl)oxy)-4-methoxyhex- 1 -en- 1 -yl)-2-chloro-6- (trifhioromethyl)pyridine and 3-((4R,5S,E)-5-((tert-butyldiphenylsilyl)oxy)-4-methoxyhex- 1 - en-l-yl)-2-chloro-6-(trifhioromethyl)pyridine (2.20 g, 4.01 mmol) and K2OSO4.2H2O (0.15 g, 0.40 mmol) were added at 0 °C. The resulting solution was stirred at room temperature for 16 h. The resulting mixture was concentrated under reduced pressure. The residue was quenched with water and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous Na2SC>4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-22% EtOAc in PE to afford a 1:4 mixture of tert-butyl ((lS,2S,4R,5R)-5-((tert- butyldiphenylsilyl)oxy)-l-(2-chloro-6-(trifluoromethyl)pyridin-3-yl)-2-hydroxy-4- methoxyhexyl)carbamate and tert-butyl ((lS,2S,4R,5S)-5-((tert-butyldiphenylsilyl)oxy)-l-(2- chloro-6-(trifhioromethyl)pyridin-3-yl)-2-hydroxy-4-methoxyhexyl)carbamate (1.50 g, 55%) as a colorless oil. MS ESI calculated for C34H44ClF3N2OsSi [M+H]⁺, 681.27; found, 681.30.

Step-6:

[1524] To a stirred mixture of a 1:4 mixture of tert-butyl ((lS,2S,4R,5R)-5-((tert- butyldiphenylsilyl)oxy)-l-(2-chloro-6-(trifluoromethyl)pyridin-3-yl)-2-hydroxy-4- methoxyhexyl)carbamate and tert-butyl ((lS,2S,4R,5S)-5-((tert-butyldiphenylsilyl)oxy)-l-(2- chloro-6-(trifhioromethyl)pyridin-3-yl)-2-hydroxy-4-methoxyhexyl)carbamate (468 mg, 0.69 mmol) in toluene (5 mL) were added CS2CO3 (448 mg, 1.37 mmol), JohnPhos (20 mg, 0.07 mmol) and Pd(OAc)2 (15 mg, 0.07 mmol) at room temperature under nitrogen atmosphere. The resulting mixture was stirred at 100 °C for 16 h. The mixture was diluted with ethyl acetate. The resulting mixture was filtered, and the filter cake was washed with ethyl acetate. The filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-15% EtOAc in PE to afford a 1:4 mixture of tertbutyl ((2S,3S)-2-((2R,3R)-3-((tert-butyldiphenylsilyl)oxy)-2-methoxybutyl)-6- (trifhioromethyl)-2,3-dihydrofuro[2,3-b]pyridin-3-yl)carbamate and tert-butyl ((2S,3S)-2- ((2R,3S)-3-((tert-butyldiphenylsilyl)oxy)-2-methoxybutyl)-6-(trifluoromethyl)-2,3- dihydrofuro[2,3-b]pyridin-3-yl)carbamate (110 mg, 25%) as a yellow oil. MS ESI calculated for C₃4H43F₃N2O5Si [M+H]⁺, 645.29; found, 645.20.

Step-7:

[1525] To a stirred mixture of 1 :4 mixture of tert-butyl ((2S,3S)-2-((2R,3R)-3-((tert- butyldiphenylsilyl)oxy)-2-methoxybutyl)-6-(trifluoromethyl)-2,3-dihydrofuro[2,3-b]pyridin- 3-yl)carbamate and tert-butyl ((2S,3S)-2-((2R,3S)-3-((tert-butyldiphenylsilyl)oxy)-2- methoxybutyl)-6-(trifluoromethyl)-2,3-dihydrofuro[2,3-b]pyridin-3-yl)carbamate (425 mg, 0.66 mmol) in THF (5 mL) was added TBAF (344 mg, 1.32 mmol) at room temperature under nitrogen atmosphere. The resulting mixture was stirred at room temperature for 16 h under nitrogen atmosphere. The resulting mixture was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-53% EtOAc in PE to afford a 1:4 mixture of tert-butyl ((2S,3S)-2-((2R,3R)-3-hydroxy-2-methoxybutyl)-6- (trifhioromethyl)-2,3-dihydrofuro[2,3-b]pyridin-3-yl)carbamate and tert-butyl ((2S,3S)-2- ((2R,3S)-3-hydroxy-2-methoxybutyl)-6-(trifluoromethyl)-2,3-dihydrofuro[2,3-b]pyridin-3- yl)carbamate (179 mg, 67%) as a white solid. MS ESI calculated for C18H25F3N2O5 [M+H]⁺, 407.17; found, 407.15.

Step-8:

[1526] A solution of a 1:4 mixture of tert-butyl ((2S,3S)-2-((2R,3R)-3-hydroxy-2- methoxybutyl)-6-(trifluoromethyl)-2,3-dihydrofuro[2,3-b]pyridin-3-yl)carbamate and tertbutyl ((2S,3S)-2-((2R,3S)-3-hydroxy-2-methoxybutyl)-6-(trifluoromethyl)-2,3- dihydrofuro[2,3-b]pyridin-3-yl)carbamate (220 mg, 0.54 mmol) and 2-(tributyl-X⁵- phosphaneylidene)acetonitrile (CAS No. 157141-27-0) (392 mg, 1.62 mmol) in toluene (6 mL) was stirred at 100 °C for 16 h under nitrogen atmosphere. The mixture was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-30% EtOAc in PE to afford a 1 :4 mixture of tert-butyl (2R,3R,4aS,9bS)-3- methoxy-2-methyl-7-(trifluoromethyl)-3,4,4a,9b-tetrahydrofuro[2,3-b:4,5-b^,]dipyridine- l(2H)-carboxylate and tert-butyl (2S,3R,4aS,9bS)-3-methoxy-2-methyl-7-(trifluoromethyl)- 3,4,4a,9b-tetrahydrofuro[2,3-b:4,5-b']dipyridine-l(2H)-carboxylate (120 mg, 57%) as a brown oil. MS ESI calculated for C18H23F3N2O4 [M+H]⁺, 389.16; found, 389.15.

Step-9:

[1527] To a stirred mixture of a 1:4 mixture of tert-butyl (2R,3R,4aS,9bS)-3-methoxy-2- methyl-7-(trifluoromethyl)-3,4,4a,9b-tetrahydrofuro[2,3-b:4,5-b^,]dipyridine-l(2H)- carboxylate and tert-butyl (2S,3R,4aS,9bS)-3-methoxy-2-methyl-7-(trifluoromethyl)- 3,4,4a,9b-tetrahydrofuro[2,3-b:4,5-b']dipyridine-l(2H)-carboxylate (120 mg, 0.31 mmol) in EtOAc (2 mL) was added HC1 in 1,4-dioxane (4.0 M, 2 mL) at 0 °C. The resulting mixture was stirred at room temperature for 1 h. The mixture was concentrated under reduced pressure. The residue was purified by Prep-Chiral-HPLC with the following conditions [Column: CHIRALPAK IB, 2*25 cm, 5 pm; Mobile Phase A: Hex(0.5% 2M NH₃-MeOH)- HPLC, Mobile Phase B: EtOH: DCM=1: 1— HPLC; Flow rate: 20 mL/min; Gradient (B%): isocratic 15% B to 15% in 7min; Wave Length: 220/254 nm; RTl(min): 4.84; RT2(min): 5.96; Sample Solvent: MeOH: DCM=1: 1-HPLC] to afford (2R,3R,4aS,9bS)-3-methoxy-2- methyl-7-(trifluoromethyl)- 1 ,2,3,4,4a,9b-hexahydrofuro[2,3-b:4,5-b']dipyridine, isomer 1 (A87) (29 mg) as a yellow solid with retention time at 4.84 minute. MS ESI calculated for C13H15F3N2O2 [M+H]⁺, 289.11; found, 289.15. ’H NMR (400 MHz, DMSO-d₆) 87.95 (d, J = 7.2 Hz, 1H), 7.39 (d, J = 7.2 Hz, 1H), 4.57 - 4.49 (m, 1H), 4.34 (d, J = 5.2 Hz, 1H), 3.48 (s, 3H), 3.20 - 3.14 (m, 1H), 2.88 - 2.77 (m, 1H), 2.68 - 2.58 (m, 1H), 2.04 - 1.93 (m, 1H), 1.61 (br, 1H), 0.97 (d, J = 6.8 Hz, 3H). Absolute stereochemistry is determined by NOESY.

Intermediate A88: (2R,3S,4aS,9bS)-3-methoxy-2-methyl-7-(trifluoromethyl)-l ,2,3,4,4a,9b- hexahydrofuro[2,3-b:4,5-b']dipyridine

A88

Step-1:

[1528] To a stirred solution of ethynyltrimethylsilane (10.0 g, 101.81 mmol) in THF (100 mL) was added n-BuLi (1.6 M/L in n-hexane) (63.5 mL, 101.81 mmol) dropwise at -78 °C under nitrogen atmosphere. The resulting mixture was stirred at -78 °C for 40 minutes under nitrogen atmosphere. Then a solution of boron trifluoride diethyl etherate (9.63 g, 67.87 mmol) in THF (10 mL) was added dropwise, this was followed by the addition of a solution of (S)-tert-butyldimethyl(oxiran-2-ylmethoxy)silane (6.39 g, 33.93 mmol) in THF (10 mL) at -78 °C. The resulting mixture was stirred at room temperature overnight. The reaction was quenched by NH4CI (sat.) at 0 °C and extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SO4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-20% ethyl acetate in petroleum ether to afford (S)-l-((tert- butyldimethylsilyl)oxy)-5-(trimethylsilyl)pent-4-yn-2-ol (8.8 g, 90%) as a brown oil. ¹H NMR (400 MHz, DMSO-J₆) 8 4.87 (d, J = 4.8 Hz, 1H), 3.61 - 3.51 (m, 3H), 2.42 - 2.23 (m, 2H), 0.88 (s, 9H), 0.11 (s, 9H), 0.05 (s, 6H).

Step-2:

[1529] To a stirred solution of (S)-l-((tert-butyldimethylsilyl)oxy)-5-(trimethylsilyl)pent-4- yn-2-ol (8.3 g, 28.96 mmol) and N¹,N¹,N⁸,N⁸-tetramethylnaphthalene-l,8-diamine (18.62 g, 86.89 mmol) in DCM (83 mL) were added MesO-BF4 (10.71 g, 72.41 mmol) and 4A molecular sieve (8.3 g) at room temperature. The resulting mixture was stirred at room temperature for 16 h. The mixture was filtered, the filter cake was washed with DCM. The filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-10% ethyl acetate in petroleum ether to afford (S)- tert-butyl((2-methoxy-5-(trimethylsilyl)pent-4-yn-l-yl)oxy)dimethylsilane (7.7 g, 88%) as a brown oil. 'H NMR (400 MHz, DMSO-d₆) 8 3.73 - 3.58 (m, 2H), 3.36 - 3.26 (m, 4H), 2.42 (d, J = 6.0 Hz, 2H), 0.88 (s, 9H), 0.12 (s, 9H), 0.06 (s, 6H).

Step-3:

[1530] To a stirred solution of (S)-tert-butyl((2-methoxy-5-(trimethylsilyl)pent-4-yn-l- yl)oxy)dimethylsilane (8.1 g, 26.94 mmol) in MeOH (90 mL) was added K2CO3 (7.45 g, 53.89 mmol) in portions at 0 °C. The resulting mixture was stirred at room temperature for 16 h. The resulting mixture was filtered, the filter cake was washed with MeOH. The filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-10% ethyl acetate in petroleum ether to afford (S)-tert- butyl((2-methoxypent-4-yn-l-yl)oxy)dimethylsilane (4.3 g, 69%) as a yellow oil. ¹H NMR (400 MHz, DMSO-d₆) 6 3.73 - 3.55 (m, 2H), 3.33 - 3.31 (m, 4H), 2.78 (t, J= 2.8 Hz, 1H), 2.43 - 2.29 (m, 2H), 0.88 (s, 9H), 0.05 (s, 6H).

Step-4:

[1531] A mixture of (S)-tert-butyl((2-methoxypent-4-yn-l-yl)oxy)dimethylsilane (16.2 g, 70.92 mmol), TEA (717 mg, 7.09 mmol), bis(cyclopenta-l,3-dien-l-yl)zirconiumbis(ylium) chloride hydride (1.82 g, 7.09 mmol) and 4,4,5,5-tetramethyl-l,3,2-dioxaborolane (13.62 g, 106.38 mmol) was stirred at 60°C for 16 h under nitrogen atmosphere. The mixture was allowed to cool down to room temperature. The reaction mixture was purified by silica gel column chromatography, eluted with 0-20% ethyl acetate in petroleum ether to afford (S,E)- tert-butyl((2-methoxy-5-(4,4,5,5-tetramethyl-l,3,2-dioxaborolan-2-yl)pent-4-en-l- yl)oxy)dimethylsilane (14.4 g, 56%) as a yellow oil. MS ESI calculated for C18H37BO4S1 [M+H]⁺, 357.26; found, 357.20.

Step-5:

[1532] To a stirred solution of (S,E)-tert-butyl((2-methoxy-5-(4,4,5,5-tetramethyl-l,3,2- dioxaborolan-2-yl)pent-4-en-l-yl)oxy)dimethylsilane (24.4 g, 68.46 mmol) and 3-bromo-2- chloro-6-(trifluoromethyl)pyridine (17.83 g, 68.46 mmol) in 1,4-dioxane (300 mL) and H2O (30 mL) were added K2CO3 (28.39 g, 205.39 mmol) and Pd(dppf)Cl₂-CH₂C12 (5.59 g, 6.84 mmol) at room temperature. The resulting mixture was stirred at 100 °C for 2 h under nitrogen atmosphere. The mixture was allowed to cool down to room temperature and concentrated under vacuum. The residue was purified by silica gel column chromatography, eluted with 0-10% ethyl acetate in petroleum ether to afford (S,E)-3-(5-((tert- butyldimethylsilyl)oxy)-4-methoxypent- 1 -en- 1 -yl)-2-chloro-6-(trifhioromethyl)pyridine (25.2 g, 89%) as a yellow oil. MS ESI calculated for Cis^vClFsNChSi [M+H]⁺, 410.15; found, 410.05.

Step-6:

[1533] To a stirred solution of (S,E)-3-(5-((tert-butyldimethylsilyl)oxy)-4-methoxypent-l- en-l-yl)-2-chloro-6-(trifhioromethyl)pyridine (20.0 g, 48.78 mmol) and l,l-bis(acetyloxy)-3- oxo-3H-ll^A[5],2-benziodaoxol-l-yl acetate (31.04 g, 73.17 mmol) in DMSO (300 mL) was added 4-methylbenzene-l -sulfonic acid hydrate (927 mg, 4.87 mmol) at room temperature. The resulting mixture was stirred at 50 °C for 2 h. The mixture was allowed to cool down to room temperature and quenched with water. The resulting mixture was extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SO4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-40% ethyl acetate in petroleum ether to afford (S,E)-5-(2-chloro-6-(trifhioromethyl)pyridin-3-yl)-2-methoxypent-4-enal (8.8 g, 61%) as a yellow oil. MS ESI calculated for C12H11CIF3NO2 [M+H]⁺, 294.04; found, 294.00.

Step-7:

[1534] To a stirred solution of (S,E)-5-(2-chloro-6-(trifhioromethyl)pyridin-3-yl)-2- methoxypent-4-enal (8.8 g, 29.96 mmol) and 4A molecular sieve (8 g) in THF (100 mL) was added methylmagnesium bromide(1.0 M in THF) (89.90 mL, 89.90 mmol) dropwise at -78°C under nitrogen atmosphere. The resulting mixture was stirred at room temperature for additional 16 h. The reaction was quenched with NH4CI (sat.) at 0 °C. The mixture was filtered, the filter cake was washed with ethyl acetate. The filtrate was extracted with EtOAc. The organic layer was dried over anhydrous NaiSC After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-30% ethyl acetate in petroleum ether to afford a 10:1 mixture of (2R,3S,E)-6-(2-chloro-6-(trifluoromethyl)pyridin-3-yl)-3-methoxyhex-5-en-2-ol and (2S,3S,E)-6-(2-chloro-6-(trifluoromethyl)pyridin-3-yl)-3-methoxyhex-5-en-2-ol (7.36 g, 79%) as a yellow oil. MS ESI calculated for C13H15CIF3NO2 [M+H]⁺, 310.07; found, 310.00.

Step-8:

[1535] To a stirred solution of a 10:1 mixture of (2R,3S,E)-6-(2-chloro-6- (trifhioromethyl)pyridin-3-yl)-3-methoxyhex-5-en-2-ol and (2S,3S,E)-6-(2-chloro-6- (trifhioromethyl)pyridin-3-yl)-3-methoxyhex-5-en-2-ol (7.36 g, 23.76 mmol) and imidazole (4.85 g, 71.29 mmol) in DCM (80 mL) was added tert-butyl(chloro)diphenylsilane (9.80 g, 35.64 mmol) at 0 °C under nitrogen atmosphere. The resulting mixture was stirred at room temperature for 16 h. The mixture was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-10% ethyl acetate in petroleum ether to afford a 10:1 mixture of 3-((4S,5R,E)-5-((tert-butyldiphenylsilyl)oxy)-4- methoxyhex-l-en-l-yl)-2-chloro-6-(trifluoromethyl)pyridine and 3-((4S,5S,E)-5-((tert- butyldiphenylsilyl)oxy)-4-methoxyhex-l-en-l-yl)-2-chloro-6-(trifluoromethyl)pyridine (12.3 g, 94%) as a colorless oil. MS ESI calculated for C29H33ClF3NO2Si [M+H]⁺, 548.19; found, 548.25.

[1536] To a stirred solution of tert-butyl carbamate (8.15 g, 69.56 mmol) in propan- l-ol (174 mL) was added a solution of NaOH (2.42 g, 60.58 mmol) in H2O (152 mL) at room temperature. The mixture was stirred at room temperature for 10 minutes, thenl,3-dichloro- 5, 5-dimethylimidazolidine-2, 4-dione (6.63 g, 33.66 mmol) was added at room temperature. The mixture was stirred at room temperature for 30 minutes. This was followed by the addition of a solution of (DHQ)2PHAL (supplier: Shanghai Accela ChemBio Co., Ltd. CAS# 140924-50-1) (1.75 g, 2.244 mmol) in propan-l-ol (22.5 mL) and a solution of a 10:1 mixture of 3-((4S,5R,E)-5-((tert-butyldiphenylsilyl)oxy)-4-methoxyhex-l-en-l-yl)-2-chloro-6- (trifhioromethyl)pyridine and 3-((4S,5S,E)-5-((tert-butyldiphenylsilyl)oxy)-4-methoxyhex-l- en-l-yl)-2-chloro-6-(trifhioromethyl)pyridine (12.3 g, 22.44 mmol) in propan-l-ol (22.5 mL) dropwise at 0 °C, and then a solution of potassium osmate(VI) dihydrate (826 mg, 2.24 mmol) in NaOH (0.4 N in H2O, 5.6 mL) was added. The resulting mixture was stirred at room temperature for 16 h. The organic solvent was removed under reduced pressure. The remined mixture was extracted with EtOAc. The organic layer was dried over anhydrous Na2SC>4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-20% ethyl acetate in petroleum ether to afford a 10:1 mixture of tert-butyl ((lS,2S,4S,5R)-5-((tert- butyldiphenylsilyl)oxy)-l-(2-chloro-6-(trifhioromethyl)pyridin-3-yl)-2-hydroxy-4- methoxyhexyl)carbamate and tert-butyl ((lS,2S,4S,5S)-5-((tert-butyldiphenylsilyl)oxy)-l-(2- chloro-6-(trifhioromethyl)pyridin-3-yl)-2-hydroxy-4-methoxyhexyl)carbamate (7.25 g, 47%) as a white solid. MS ESI calculated for C34H44ClF3N2OsSi [M+H]⁺, 681.27; found, 681.30.

[1537] To a stirred solution of 10:1 mixture of tert-butyl ((lS,2S,4S,5R)-5-((tert- butyldiphenylsilyl)oxy)-l-(2-chloro-6-(trifluoromethyl)pyridin-3-yl)-2-hydroxy-4- methoxyhexyl)carbamate and tert-butyl ((lS,2S,4S,5S)-5-((tert-butyldiphenylsilyl)oxy)-l-(2- chloro-6-(trifluoromethyl)pyridin-3-yl)-2-hydroxy-4-methoxyhexyl)carbamate (7.25 g, 10.64 mmol) and CS2CO3 (6.93 g, 21.28 mmol) in Toluene (80 mL) were added Pd(OAc)2 (238 mg, 1.06 mmol) and JohnPhos (317 mg, 1.06 mmol) at room temperature. The resulting mixture was stirred at 100 °C for 16 h nitrogen atmosphere. The mixture was concentrated under vacuum. The residue was purified by silica gel column chromatography, eluted with 0-20% ethyl acetate in petroleum ether to afford a 10:1 mixture of tert-butyl ((2S,3S)-2-((2S,3R)-3- ((tert-butyldiphenylsilyl)oxy)-2-methoxybutyl)-6-(trifluoromethyl)-2,3-dihydrofuro[2,3- b]pyridin-3-yl)carbamate and tert-butyl ((2S,3S)-2-((2S,3S)-3-((tert-butyldiphenylsilyl)oxy)- 2-methoxybutyl)-6-(trifhioromethyl)-2,3-dihydrofuro[2,3-b]pyridin-3-yl)carbamate (4.32 g, 62%) as a yellow oil. MS ESI calculated for C34H43F3N2OsSi [M+H]⁺, 645.29; found, 645.25.

Step-11:

[1538] To a solution of a 10:1 mixture of tert-butyl ((2S,3S)-2-((2S,3R)-3-((tert- butyldiphenylsilyl)oxy)-2-methoxybutyl)-6-(trifluoromethyl)-2,3-dihydrofuro[2,3-b]pyridin- 3-yl)carbamate and tert-butyl ((2S,3S)-2-((2S,3S)-3-((tert-butyldiphenylsilyl)oxy)-2- methoxybutyl)-6-(trifluoromethyl)-2,3-dihydrofuro[2,3-b]pyridin-3-yl)carbamate (4.72 g, 7.32 mmol) in THF (50 mL) was added TBAF (3.83 g, 14.64 mmol). The mixture was stirred at room temperature 16 h. The resulting mixture was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-80% ethyl acetate in petroleum ether to afford a 10:1 mixture of tert-butyl ((2S,3S)-2-((2S,3R)-3- hydroxy-2-methoxybutyl)-6-(trifluoromethyl)-2,3-dihydrofuro[2,3-b]pyridin-3-yl)carbamate and tert-butyl ((2S,3S)-2-((2S,3S)-3-hydroxy-2-methoxybutyl)-6-(trifluoromethyl)-2,3- dihydrofuro[2,3-b]pyridin-3-yl)carbamate (2.2 g, 73%) as a white solid. MS ESI calculated for C18H25F3N2O5 [M+H]⁺, 407.17; found, 407.15.

Step- 12: [1539] A solution of 10:1 mixture of tert-butyl ((2S,3S)-2-((2S,3R)-3-hydroxy-2- methoxybutyl)-6-(trifluoromethyl)-2,3-dihydrofuro[2,3-b]pyridin-3-yl)carbamate and tertbutyl ((2S,3S)-2-((2S,3S)-3-hydroxy-2-methoxybutyl)-6-(trifluoromethyl)-2,3- dihydrofuro[2,3-b]pyridin-3-yl)carbamate (2.0 g, 4.92 mmol) and 2-(tributyl-k⁵- phosphaneylidene)acetonitrile (CAS No. 157141-27-0) (3.56 g, 14.76 mmol) in Toluene (40 mL) was stirred at 110 °C for 5 h under nitrogen atmosphere. The mixture was concentrated under vacuum. The residue was purified by silica gel column chromatography, eluted with 0- 50% ethyl acetate in petroleum ether to afford tert-butyl (2R,3S,4aS,9bS)-3-methoxy-2- methyl-7-(trifhioromethyl)-3,4,4a,9b-tetrahydrofuro[2,3-b:4,5-b']dipyridine-l(2H)- carboxylate, isomer 1 (1.67 g, 87%) as a yellow oil. MS ESI calculated for C18H23F3N2O4 [M+H]⁺, 389.16; found, 389.10.

[1540] The separation also afford tert-butyl (2S,3S,4aS,9bS)-3-methoxy-2-methyl-7- (trifluoromethyl)-3,4,4a,9b-tetrahydrofuro[2,3-b:4,5-b']dipyridine-l(2H)-carboxylate , isomer 2 (148 mg, 7%) as a colorless oil. MS ESI calculated for C18H23F3N2O4 [M+H]⁺, 389.16; found, 389.10.

Step-13:

[1541] To a stirred solution of tert-butyl (2R,3S,4aS,9bS)-3-methoxy-2-methyl-7- (trifhioromethyl)-3,4,4a,9b-tetrahydrofuro[2,3-b:4,5-b']dipyridine-l(2H)-carboxylate, isomer 1 (1.67 g, 4.30 mmol) in EtOAc (18 mL) was added HC1 (4.0 M in 1,4-dioxane) (18 mL) at 0 °C. The resulting mixture was stirred at room temperature for 1 h. The mixture was concentrated under vacuum and then quenched with water. The mixture was basified by NaHCCh (aq.) to pH 8 and extracted with EtOAc. The organic layer was dried over anhydrous Na2SO4. After filtration, the filtrate was concentrated under reduced pressure to afford (2R,3S,4aS,9bS)-3-methoxy-2-methyl-7-(trifluoromethyl)-l,2,3,4,4a,9b- hexahydrofuro[2,3-b:4,5-b']dipyridine (A88) (1 .02 g, 82%) as a yellow solid. MS ESI calculated for C13H15F3N2O2 [M+H]⁺, 289.11; found, 289.00. 'H NMR (400 MHz, DMSO- df>) 3 8.30 (d, J= 7.6 Hz, 1H), 7.62 (d, J = 7.6 Hz, 1H), 5.15 (q, J = 5.6 Hz, 1H), 5.04 - 4.93 (m, 1H), 3.49 - 3.40 (m, 2H), 3.36 (s, 3H), 3.30 - 3.19 (m, 1H), 2.33 - 2.22 (m, 1H), 1.30 (d, J = 6.8 Hz, 3H). Absolute stereochemistry is determined by NOESY.

Intermediate A89: 1:1 mixture of (lR,2R)-2-((2R,4aS,10bS)-2-methyl-l,2,3,4a,5,10b- hexahydrochromeno[3,4-b] [ 1 ,4]oxazin-8-yl)cyclopropane- 1 -carbonitrile and (1 S,2S)-2- ((2R,4aS, 10bS)-2-methyl- 1 ,2, 3, 4a, 5 , 1 Ob-hexahydrochromeno [3 ,4-b] [ 1 ,4] oxazin-8- yl)cyclopropane- 1 -carbonitrile

[1542] To a solution of tert-butyl (2R,4aS,10bS)-8-bromo-2-methyl-2,3,4a,10b- tetrahydrochromeno[3,4-b][l,4]oxazine-l(5H)-carboxylate (800 mg, 2.08 mmol) in toluene (8 mL) and H2O (1 mL) were added potassium rac-((lR,2R)-2-

(ethoxycarbonyl)cyclopropyl)trifluoroborate (687 mg, 3.12 mmol), di(l-adamantyl)-N- butylphosphine (37 mg, 0.10 mmol), CS2CO3 (1.35 g, 4.16 mmol) and Pd(AcO)2 (23 mg, 0.10 mmol) at room temperature. The reaction was stirred at 90 °C for 1 h under nitrogen atmosphere. The resulting mixture was concentrated under vacuum. The residue was purified by Combi Flash (Biotage Isolera Prime) using a 40 g silica gel column eluted with 0-50% ethyl acetate in petroleum ether to afford to afford a 1:1 mixture of tert-butyl (2R,4aS,10bS)- 8-((lR,2R)-2-(ethoxycarbonyl)cyclopropyl)-2-methyl-2,3,4a,10b-tetrahydrochromeno[3,4- b][ 1,4] oxazine- l(5H)-carboxylate and tert-butyl (2R,4aS,10bS)-8-((lS,2S)-2-

(ethoxycarbonyl)cyclopropyl)-2-methyl-2,3,4a,10b-tetrahydrochromeno[3,4-b][l,4]oxazine-

1 (5H)-carboxylate (700 mg, 80%) as a white solid. MS ESI calculated for C23H31NO6

[M+l]⁺, 418.22; found,418.20.

Step-2:

[1543] To a stirred solution of 1: 1 mixture of tert-butyl (2R,4aS,10bS)-8-((lR,2R)-2- (ethoxycarbonyl)cyclopropyl)-2-methyl-2,3,4a,10b-tetrahydrochromeno[3,4-b][l,4]oxazine- l(5H)-carboxylate and tert-butyl (2R,4aS,10bS)-8-((lS,2S)-2-(ethoxycarbonyl)cyclopropyl)- 2-methyl-2,3,4a, 10b-tetrahydrochromeno[3,4-b] [1 ,4] oxazine- l(5H)-carboxylate (800 mg, 1.91 mmol) in methanol (2 mL) and H2O (2 mL) was added LiOH (92 mg, 3.83 mmol) at room temperature. The resulting mixture was stirred at 50 °C for 1 h. The resulting mixture was concentrated under vacuum to afford to afford a 1: 1 mixture of (lR,2R)-2-

((2R,4aS, 1 ObS)- 1 -(tert-butoxycarbonyl)-2-methyl- 1 ,2, 3, 4a, 5 , 1 Ob-hexahydrochromeno [3 ,4- b][l,4]oxazin-8-yl)cyclopropane-l-carboxylic acid and (lS,2S)-2-((2R,4aS,10bS)-l-(tert- butoxycarbonyl)-2-methyl- 1 ,2,3 ,4a, 5 , 1 Ob-hexahydrochromeno [3 ,4-b] [ 1 ,4] oxazin-8- yl)cyclopropane-l -carboxylic acid (750 mg, crude) as a white solid. MS ESI calculated for C21H27NO6 [M+l]⁺, 390.18; found, 390.15.

Step-3: [1544] To a stirred solution of 1: 1 mixture of (lR,2R)-2-((2R,4aS,10bS)-l-(tert- butoxycarbonyl)-2-methyl- 1 ,2,3 ,4a, 5 , 1 Ob-hexahydrochromeno [3 ,4-b] [ 1 ,4] oxazin-8- yl)cyclopropane-l -carboxylic acid and (lS,2S)-2-((2R,4aS,10bS)-l-(tert-butoxycarbonyl)-2- methyl- 1 ,2, 3, 4a, 5 , 1 Ob-hexahydrochromeno [3 ,4-b] [ 1 ,4] oxazin-8-yl)cyclopropane- 1 - carboxylic acid (750 mg, 1.91 mmol) in DMF (4 mL) were added HATU (1.09 g, 2.87 mmol), DIEA (742 mg, 5.74 mmol) and ammonium chloride (205 mg, 3.83 mmol) at room temperature under nitrogen atmosphere. The resulting mixture was stirred at room temperature for 2 h. The reaction was quenched by water and extracted with EtOAc. The combined organic layers were washed with water, dried over anhydrous NaiSCL. After filtration, the filtrate was concentrated under reduced pressure. The resulting residue was purified by Combi Flash (Biotage Isolera Prime) using a 40 g silica gel column eluted with 0- 50% ethyl acetate in petroleum ether to afford to afford a 1:1 mixture of tert-butyl (2R,4aS,10bS)-8-((lR,2R)-2-carbamoylcyclopropyl)-2-methyl-2,3,4a,10b- tetrahydrochromeno[3,4-b][l,4]oxazine-l(5H)-carboxylate and tert-butyl (2R,4aS,10bS)-8- (( 1 S ,2S)-2-carbamoylcyclopropyl)-2-methyl-2,3,4a, 1 Ob-tetrahydrochromen-o [3 ,4- b][ 1,4] oxazine- l(5H)-carboxylate (700 mg, 94%) as a white solid. MS ESI calculated for C21H28N2O5 [M+l]⁺, 389.20; found, 389.15.

Step-4:

[1545] To a stirred solution of 1: 1 mixture of tert-butyl (2R,4aS,10bS)-8-((lR,2R)-2- carbamoylcyclopropyl)-2-methyl-2,3 ,4a, 1 Ob-tetrahydrochromeno [3,4-b] [ 1 ,4] oxazine- 1 (5H)- carboxylate and tert-butyl (2R,4aS,10bS)-8-((lS,2S)-2-carbamoylcyclopropyl)-2-methyl- 2,3,4a,10b-tetrahydrochromen-o[3,4-b][l,4]oxazine-l(5H)-carboxylate (800 mg, 2.06 mmol) and pyridine (651 mg, 8.23 mmol) in DCM (8 mL) was added phosphoryl trichloride (237 mg, 1.54 mmol) at room temperature under nitrogen atmosphere. The resulting mixture was stirred at room temperature for 16 h. The resulting mixture was concentrated under vacuum. The resulting residue was purified by Combi Flash (Biotage Isolera Prime) using a 40 g silica gel column eluted with 0-50% ethyl acetate in petroleum ether to afford to afford a 1:1 mixture of tert-butyl (2R,4aS,10bS)-8-((lR,2R)-2-cyanocyclopropyl)-2-methyl-2,3,4a,10b- tetrahydrochromeno[3,4-b][l,4]oxazine-l(5H)-carboxylate and tert-butyl (2R,4aS,10bS)-8- (( 1 S ,2S)-2-cyanocyclopropyl)-2-methyl-2,3 ,4a, 1 Ob-tetrahydrochromeno- [3 ,4- b][ 1,4] oxazine- l(5H)-carboxylate (400 mg, 52%) as a yellow oil. MS ESI calculated for C21H26N2O4 [M+l]⁺, 371.19; found, 371.15.

Step-5:

A89

[1546] A solution of 1 : 1 mixture of tert-butyl (2R,4aS, 10bS)-8-((lR,2R)-2- cyanocyclopropyl)-2-methyl-2,3,4a, 1 Ob-tetrahydrochromeno [3 ,4-b] [ 1 ,4] oxazine- 1 (5H)- carboxylate and tert-butyl (2R,4aS,10bS)-8-((lS,2S)-2-cyanocyclopropyl)-2-methyl- 2,3,4a,10b-tetrahydrochromeno-[3,4-b][l,4]oxazine-l(5H)-carboxylate (100 mg, 0.27 mmol) and HC1 in 1,4-dioxane (4.0 M) (1 mL) was stirred at room temperature for 1 h. The resulting mixture was concentrated under vacuum to afford a 1:1 mixture of (lR,2R)-2- ((2R,4aS, 10bS)-2-methyl- 1 ,2, 3, 4a, 5, 10b-hexahydrochromeno[3,4-b] [ 1 ,4]oxazin-8- yl)cyclopropane-l -carbonitrile hydrochloride and (lS,2S)-2-((2R,4aS,10bS)-2-methyl- 1 ,2, 3, 4a, 5, 10b-hexahydrochromeno[3,4-b] [1 ,4]oxazin-8-yl)cyclopropane- 1 -carbonitrile hydrochloride (A89) (100 mg, crude) as a white solid. MS ESI calculated for C16H18N2O2 [M+H]⁺, 271.14; found, 271.15.

Intermediate A90: rel-(4aR,9bR)-7-chloro- 1 ,2,3,4,4a,9b-hexahydrofuro[2,3-b:4,5- b']dipyridine

[1547] A mixture of rel-tert-butyl (4aS,9bS)-7-chloro-3,4,4a,9b-tetrahydrofuro[2,3-b:4,5- b']dipyridine-l(2H)-carboxylate (400 mg, 1.28 mmol) and HC1 (4M in dioxane) (4 mL) was stirred at 25 °C for 1 h. The solvents were removed under vacuum to afford rel-(4aR,9bR)-7- chloro-l,2,3,4,4a,9b-hexahydrofuro[2,3-b:4,5-b']dipyridine hydrochloride (A90) (380 mg) as white solid. MS ESI calculated for C10H11CIN2O [M+H]⁺, 211.06; found, 211.00. ¹H NMR (300 MHz, DMSO- fc) 5 10.75 (br, 1H), 8.87 (br, 1H), 8.05 (d, J = 7.8 Hz, 1H), 7.21 (d, J = 7.8 Hz, 1H), 5.04 - 4.76 (m, 2H), 3.25 - 2.75 (m, 2H), 2.33 - 1.94 (m, 2H), 1.89 - 1.60 (m, 2H).

Intermediate A91 isomer 1: rel-(3R,4aS,9bS)-3-fhioro-7-(trifluoromethyl)-l,2,3,4,4a,9b- hexahydrofuro[2,3-b:4,5-b']dipyridine isomer 1

Isomer 1

Intermediate A91 isomer 2: rel-(3R,4aR,9bR)-3-fhioro-7-(trifluoromethyl)-l,2,3,4,4a,9b- hexahydrofuro[2,3-b:4,5-b']dipyridine isomer 2

Isomer 2

Step-1:

[1548] To a solution of dimethyl 2-fluoromalonate (100 g, 666.20 mmol) in N,N- dimethylacetamide (30 mL) was added CS2CO3 (217 g, 666.20 mmol) at 0 °C. After stirring at 0 °C for 10 minutes, then 3-bromoprop-l-yne (79.2 g, 666.20 mmol) was added slowly. The mixture was stirred at 20 °C for 1.5 h. The reaction was quenched by the addition of NH4CI (sat.) at 20 °C and extracted with EtOAc. The combined organic layers were washed with EtOAc, dried over anhydrous Na2SO4. After filtration, the filtrate was concentrated under reduced pressure. Then the residue was dissolved in DMSO (40 mL) and H2O (1.4 mL), LiCl (84.72 g, 1998.60 mmol) was added. The resulting mixture was stirred at 110 °C for additional lh. The reaction was quenched by water and extracted with EtOAc. The combined organic layers were washed with brine (1x10 mL), dried over anhydrous Na2SO4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with PE / EtOAc (5:1) to afford a 1: 1 mixture of methyl (R)-2-fluoropent-4-ynoate and methyl (S)-2-fluoropent-4-ynoate (35 g, 40% yield) as a yellow oil. 'H NMR (400 MHz, CDCI3-J) 5 5.13 - 4.90 (m, 1H), 3.83 (s, 3H), 2.90 - 2.74 (m, 2H), 2.11 (t, J = 2.8 Hz, 1H).

Step-2: [1549] To a stirred solution of 1:1 mixture of methyl (R)-2-fluoropent-4-ynoate and methyl (S)-2-fluoropent-4-ynoate ((100 g, 768.5 mmol) and 4,4,5,5-tetramethyl-l,3,2-dioxaborolane (118.0 g, 922.2 mmol) in THF (50 mL) were added EtsN (7.8 g, 76.8 mmol) and bis(cyclopenta-l,3-dien-l-yl)zirconiumbis(ylium) chloride hydride (19.7 g, 76.8 mmol) at 0°C under nitrogen atmosphere. The resulting mixture was stirred at 60°C for 2 h). The reaction was quenched by water and extracted with CH2CI2. The combined organic layers were washed with water, dried over anhydrous Na2SC>4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with PE / EtOAc (20:1) to afford a 1:1 mixture of methyl (R, E)-2- fluoro-5-(4,4,5,5-tetramethyl-l,3,2-dioxaborolan-2-yl)pent-4-enoate and methyl (S,E)-2- fluoro-5-(4,4,5,5-tetramethyl-l,3,2-dioxaborolan-2-yl)pent-4-enoate (80 g, 34%) as a yellow oil. MS ESI calculated for C12H20BFO4 [M+H]⁺, 259.14; found, 259.00. 'H NMR (300 MHz, CDCI3) 5 6.60 - 6.40 (m, 1H), 5.64 - 5.44 (m, 1H), 5.14 - 4.77 (m, 1H), 3.75 (s, 3H), 2.79 - 2.59 (m, 2H), 1.22 (s, 12H).

Step-3:

[1550] To a stirred solution of 1:1 mixture of methyl (R, E)-2-fluoro-5-(4, 4,5,5- tetramethyl-l,3,2-dioxaborolan-2-yl)pent-4-enoate and methyl (S, E)-2-fluoro-5-(4, 4,5,5- tetramethyl-l,3,2-dioxaborolan-2-yl)pent-4-enoate (30.0 g, 116.234 mmol) and 3-bromo-2- chloro-6-(trifhioromethyl)pyridine (30.27 g, 116.234 mmol) in Dioxane (300 mL) and water (30 mL) were added K2CO3 (1.61 g, 11.62 mmol) and Pd(dppf)C12-CH₂C12 (9.49 g, 11.62 mmol). The resulting mixture was stirred at 90 °C for 2 h. The reaction was quenched by water and extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SO4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with PE / EtOAc (5:1) to afford a 1:1 mixture of methyl (R,E)-5-(2-chloro-6-(trifhioromethyl)pyridin-3-yl)-2- fluoropent-4-enoate and methyl (S,E)-5-(2-chloro-6-(trifluoromethyl)pyridin-3-yl)-2- fluoropent-4-enoate (30 g, 82%) as a brown oil. MS ESI calculated for C12H10CIF4NO2 [M+H]⁺, 312.03; found, 312.05. Step-4:

[1551] To a stirred solution of 1:1 mixture of methyl (R, E)-5-(2-chloro-6- (trifluoromethyl)pyridin-3-yl)-2-fluoropent-4-enoate and methyl (S,E)-5-(2-chloro-6- (trifhioromethyl)pyridin-3-yl)-2-fluoropent-4-enoate (10 g, 32.1 mmol) in THF (100 mL) was added CaCh (3.56 g, 32.1 mmol) at 0°C . Then NaBFU (2.43 g, 64.172 mmol) was added in portions at 0 °C. The resulting mixture was stirred at 25 °C for 1 h. The reaction was quenched by the addition of NH4CI (sat.) at 0 °C. The resulting mixture was extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous NazSt After filtration, the filtrate was concentrated under reduced pressure to afford 1 : 1 mixture of (R,E)-5-(2-chloro-6-(trifhioromethyl)pyridin-3-yl)-2-fluoropent-4-en- 1 -ol and (S,E)-5-(2- chloro-6-(trifluoromethyl)pyridin-3-yl)-2-fluoropent-4-en-l-ol (7 g, 77%) as a yellow oil. MS ESI calculated for C12H10CIF4NO2 [M+H]⁺, 284.04; found, 284.10.

Step-5:

[1552] To a stirred solution of 1: 1 mixture of (R,E)-5-(2-chloro-6-(trifluoromethyl)pyridin- 3-yl)-2-fluoropent-4-en- 1 -ol and (S,E)-5-(2-chloro-6-(trifluoromethyl)pyridin-3-yl)-2- fluoropent-4-en-l-ol (30 g, 105.76 mmol) in DCM (300 mL) were added imidazole (21.60 g, 317.3 mmol) and tert-butyl(chloro)diphenylsilane (32.0 116.3 mmol) at 0°C under nitrogen atmosphere. The resulting mixture was stirred at 25 °C for 1 h. The resulting mixture was concentrated under vacuum. The residue was purified by flash column chromatography with PE/EtOAc (20/1) to afford a 1:1 mixture of (R,E)-3-(5-((tert-butyldiphenylsilyl)oxy)-4- fluoropent-l-en-l-yl)-2-chloro-6-(trifluoromethyl)pyridine and (S,E)-3-(5-((tert- butyldiphenylsilyl)oxy)-4-fluoropent-l-en-l-yl)-2-chloro-6-(trifluoromethyl)pyridine (45 g, 81% yield) as a colorless oil. MS ESI calculated for C27H28ClF4NO2Si [M+H]⁺, 522.16; found, 522.10.

Step-6: [1553] To a stirred solution of tert-butyl carbamate (20.2 g, 172.4 mol) in propan-l-ol (144 mL) was added a solution of NaOH (6.9 g, 172.4mmol) in water (144 mL), then DCDMH (33.97 g, 172.39 mmol) was added in portions at 0 °C. After stirring at room temperature for 30 minutes, (DHQ)2PHAL (supplier: Shanghai Accela ChemBio Co., Ltd. CAS# 140924-50- 1) (4.48 g, 5.747 mmol) was added in portions at 0 °C. This was followed by the addition of 1:1 mixture of (R,E)-3-(5-((tert-butyldiphenylsilyl)oxy)-4-fhioropent-l-en-l-yl)-2-chloro-6- (trifluoromethyl)pyridine and (S,E)-3-(5-((tert-butyldiphenylsilyl)oxy)-4-fluoropent-l-en-l- yl)-2-chloro-6-(trifluoromethyl)pyridine (30.0 g, 57.47 mmol) and Potassium osmate(VI) dihydrate (2.12 g, 5.747 mmol) at 0 °C. The resulting mixture was stirred at room temperature for additional 1 h. The resulting mixture was extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SO4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by flash column chromatography with PE/EtOAc (20/1) to afford a 1: 1 mixture of tert-butyl ((lR*,2R*,4R)-5-((tert-butyldiphenylsilyl)oxy)-l-(2-chloro-6-(trifluoromethyl)pyridin-3-yl)- 4-fluoro-2-hydroxypentyl)carbamate and tert-butyl ((lR*,2R*,4S)-5-((tert- butyldiphenylsilyl)oxy)-l-(2-chloro-6-(trifluoromethyl)pyridin-3-yl)-4-fluoro-2- hydroxypentyl)carbamate (30 g, 79% yield) as a colorless oil. MS ESI calculated for C32H29ClF₄NO₄Si [M+H]⁺, 655.23; found, 655.25

Step-7:

[1554] To a stirred solution of 1: 1 mixture of tert-butyl ((lR*,2R*,4R)-5-((tert- butyldiphenylsilyl)oxy)-l-(2-chloro-6-(trifluoromethyl)pyridin-3-yl)-4-fluoro-2- hydroxypentyl)carbamate and tert-butyl ((lR*,2R*,4S)-5-((tert-butyldiphenylsilyl)oxy)-l-(2- chloro-6-(trifluoromethyl)pyridin-3-yl)-4-fluoro-2-hydroxypentyl)carbamate (30 g, 10.53 mmol) in toluene (300 mL) were added CS2CO3 (10.29 g, 31.593 mmol), Pd(AcO)2 (236 mg, 1.05 mmol) and JohnPhos (0.31 g, 1.05 mmol). The resulting mixture was stirred at 100 °C for 2 h under nitrogen atmosphere. The resulting mixture was concentrated under vacuum. The residue was purified by reverse phase flash column chromatography with 10%~50% MeCN in Water to afford a 1:1 mixture of tert-butyl ((2R*,3R*)-2-((R)-3-((tert- butyldiphenylsilyl)oxy)-2-fhioropropyl)-6-(trifhioromethyl)-2,3-dihydrofuro[2,3-b]pyridin-3- yl)carbamate and tert-butyl ((2R*,3R*)-2-((S)-3-((tert-butyldiphenylsilyl)oxy)-2- fluoropropyl)-6-(trifluoromethyl)-2,3-dihydrofuro[2,3-b]pyridin-3-yl)carbamate (2.1 g, 32% yield) as a yellow oil. MS ESI calculated for C32H3sF4N2O4Si [M+H]⁺, 619.25; found, 619.15

Step-8:

[1555] To a solution of 1 : 1 mixture of tert-butyl ((2R*,3R*)-2-((R)-3-((tert- butyldiphenylsilyl)oxy)-2-fluoropropyl)-6-(trifluoromethyl)-2,3-dihydrofuro[2,3-b]pyridin-3- yl)carbamate and tert-butyl ((2R*,3R*)-2-((S)-3-((tert-butyldiphenylsilyl)oxy)-2- fluoropropyl)-6-(trifluoromethyl)-2,3-dihydrofuro[2,3-b]pyridin-3-yl)carbamate (12 g, 19.39 mmol) in THF (50 mL) was added TBAF (1.0 M in THF) (20 mL, 20 mmol) at room temperature. The mixture was stirred at room temperature for 1 h. The resulting mixture was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with PE / EtOAc (5:1) to afford a 1:1 mixture of tert-butyl ((2R*,3R*)-2-((R)-2-fluoro-3-hydroxypropyl)-6-(trifluoromethyl)-2,3-dihydrofuro[2,3- b]pyridin-3-yl)carbamate and tert-butyl ((2R*,3R*)-2-((S)-2-fhroro-3-hydroxypropyl)-6- (trifhioromethyl)-2,3-dihydrofuro[2,3-b]pyridin-3-yl)carbamate (6.8 g, 92%) as a brown oil. MS ESI calculated for C16H20F4N2O4 [M+H]⁺, 381.14; found, 381.05. 'H NMR (400 MHz, CDCI3) 8 7.84 (d, J= 7.6 Hz, 1H), 7.32 (dd, J = 7.6, 2.4 Hz, 1H), 5.61 - 5.47 (m, 1H), 5.15 - 4.71 (m, 3H), 4.00 - 3.66 (m, 2H), 2.31 - 2.17 (m, 1H), 2.03 - 1.86 (m, 2H), 1.49 (s, 9H).

Step-9:

[1556] A mixture of 1:1 mixture of tert-butyl ((2R*,3R*)-2-((R)-2-fluoro-3- hydroxypropyl)-6-(trifhioromethyl)-2,3-dihydrofuro[2,3-b]pyridin-3-yl)carbamate and tertbutyl ((2R*,3R*)-2-((S)-2-fluoro-3-hydroxypropyl)-6-(trifhioromethyl)-2,3-dihydrofuro[2,3- b]pyridin-3-yl)carbamate (12.0 g, 31.55 mmol) and 2-(tributyl ⁵- phosphaneylidene)acetonitrile (CAS No. 157141-27-0) (15.23 g, 63.10 mmol) in Toluene (120 mL) was stirred at 110 °C for 2 h. The resulting mixture was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with PE / EtOAc (5:1) to afford rel-tert-butyl (3R,4aS,9bS)-3-fluoro-7-(trifluoromethyl)-3,4,4a,9b- tetrahydrofuro[2,3-b:4,5-b']dipyridine-l(2H)-carboxylate isomer 1 (1.8 g, 33%) as a yellow solid and rel-tert-butyl (3R,4aR,9bR)-3-fluoro-7-(trifluoromethyl)-3,4,4a,9b- tetrahydrofuro[2,3-b:4,5-b']dipyridine-l(2H)-carboxylate isomer 2 (1.35 g, 25%) as a yellow solid.

[1557] rel-tert-butyl (3R,4aS,9bS)-3-fluoro-7-(trifluoromethyl)-3,4,4a,9b- tetrahydrofuro[2,3-b:4,5-b']dipyridine-l(2H)-carboxylate isomer 1 (1.8 g) was further purified by Prep-chiral SFC with following condition [(S, S)-WHELK-O1 SFC, 3*25 cm, 10 pm; Mobile Phase A: CO2, Mobile Phase B: MEOH; Flow rate: 80 mL/min; Gradient (B%): isocratic 15% B; RTl(min): 3.8; RT2(min): 5; Sample Solvent: MEOH] to afford rel-tert- butyl (3R,4aS ,9bS)-3-fluoro-7 -(trifluoromethyl)-3 ,4,4a,9b-tetrahydrofuro [2,3-b :4,5- b']dipyridine-l(2H)-carboxylate isomer 1 (1.5 g) with retention time at 3.8 minute.

[1558] rel-tert-butyl (3R,4aS,9bS)-3-fluoro-7-(trifhioromethyl)-3,4,4a,9b- tetrahydrofuro[2,3-b:4,5-b']dipyridine-l(2H)-carboxylate isomer 1: MS ESI calculated for C16H18F4N2O3 [M+H]⁺, 363.13; found, 363.00. 'H NMR (400 MHz, CDCI3) 57.82 (s, 1H), 7.31 (d, J = 7.4 Hz, 1H), 6.05 - 5.65 (m, 1H), 5.20 - 5.05 (m, 1H), 5.03 - 4.70 (m, 1H), 4.45

- 3.98 (m, 1H), 2.99 - 2.43 (m, 2H), 2.35 - 2.07 (m, 1H), 1.53 (s, 9H).

[1559] rel-tert-butyl (3R,4aR,9bR)-3-fluoro-7-(trifluoromethyl)-3,4,4a,9b- tetrahydrofuro[2,3-b:4,5-b']dipyridine-l(2H)-carboxylate isomer 2: MS ESI calculated for C16H18F4N2O3 [M+H]⁺, 363.13; found, 363.00. ’H NMR (400 MHz, CDCI3) 8 7.75 (s, 1H), 7.29 (d, J = 7.6 Hz, 1H), 6.03 - 5.63 (m, 1H), 5.25 - 5.05 (m, 1H), 5.09 - 4.77 (m, 1H), 4.48

- 4.14 (m, 1H), 3.00 - 2.63 (m, 1H), 2.60 - 2.34 (m, 1H), 2.33 - 2.06 (m, 1H), 1.52 (s, 9H).

Step- 10: isomer 1 A91 isomer 1

[1560] To a mixture of rel-tert-butyl (3R,4aS,9bS)-3-fluoro-7-(trifluoromethyl)-3,4,4a,9b- tetrahydrofuro[2,3-b:4,5-b']dipyridine-l(2H)-carboxylate isomer 1 (1.1 g, 3.03 mmol) in Dioxane (10 mL) was added HC1 (4.0 M in 1,4-dioxane) (5 mL) at room temperature. The mixture was stirred at room temperature for 3 h. The mixture was concentrated under reduced pressure to afford rel-(3R,4aS,9bS)-3-fluoro-7-(trifluoromethyl)-l,2,3,4,4a,9b- hexahydrofuro[2,3-b:4,5-b']dipyridine hydrochloride isomer 1 (A91 isomer 1) (1.1 g, crude) as a white solid. MS ESI calculated for C11H10F4N2O [M+H]⁺, 263.07; found, 263.05. 'H NMR (400 MHz, DMSO-</₆) 8 10.36 (br, 2H), 8.38 (d, J = 7.6 Hz, 1H), 7.62 (d, J = 7.6 Hz, 1H), 5.38 - 5.05 (m, 3H), 3.63 - 3.40 (m, 1H), 3.35 - 3.08 (m, 1H), 2.73 - 2.67 (m, 1H), 2.55 - 2.37 (m, 1H). Absolute stereochemistry was not determined.

Step-11: [1561] To a solution of rel-tert-butyl (3R,4aR,9bR)-3-fluoro-7-(trifluoromethyl)-3,4,4a,9b- tetrahydrofuro[2,3-b:4,5-b']dipyridine-l(2H)-carboxylate isomer 2 (1.3 g, 3.58 mmol) in Dioxane (10 mL) was added HC1 (4.0 M in 1,4-dioxane) (5 mL) at room temperature. The reaction mixture was stirred at 25 °C for 3 hours. The mixture was concentrated under reduced pressure to afford rel-(3R,4aR,9bR)-3-fluoro-7-(trifluoromethyl)-l,2,3,4,4a,9b- hexahydrofuro[2,3-b:4,5-b']dipyridine isomer 2 (A91 isomer 2) (1.2 g, crude) as a brown solid. MS ESI calculated for C11H10F4N2O [M+H]⁺, 263.07; found, 263.05. 'H NMR (400 MHz, DMSO-J₆) 8 11.52 (br, lH), 9.16 (br, 1H), 8.29 (d, J = 7.6 Hz, 1H), 7.61 (d, J = 7.6 Hz, 1H), 5.31 - 4.96 (m, 3H), 3.51 - 3.24 (m, 2H), 2.71 - 2.63 (m, 1H), 2.49 - 2.30 (m, 1H). Absolute stereochemistry was not determined.

Intermediate A92 isomer 1: rel-(4R,4aS,9bR)-7-chloro-4-methoxy-l,2,3,4,4a,9b- hexahydrofuro[2,3-b:4,5-b']dipyridine isomer 1 isomer 1

Intermediate A92 isomer 2: rel-(4R,4aR,9bS)-7-chloro-4-methoxy-l,2,3,4,4a,9b- hexahydrofuro[2,3-b:4,5-b']dipyridine isomer 2 isomer 2

Step-1:

[1562] A mixture of 1:1 mixture of (R,E)-tert-butyl((3-methoxy-5-(4,4,5,5-tetramethyl- l,3,2-dioxaborolan-2-yl)pent-4-en-l-yl)oxy)diphenylsilane and (S,E)-tert-butyl((3-methoxy- 5-(4,4,5,5-tetramethyl-l,3,2-dioxaborolan-2-yl)pent-4-en-l-yl)oxy)diphenylsilane (30 g, 62.43 mmol), 3-bromo-2,6-dichloropyridine (12.75 g, 56.19 mmol), AcOK (18.38 g, 187.29 mmol) and Pd(dppf)Ch-CH2C12 (5.10 g, 6.24 mmol) in dioxane (300 mL) and H2O (30 mL) was stirred at 100 °C for 2 h under nitrogen atmosphere. The reaction mixture was quenched with water and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under vacuum. The solvents were removed under vacuum. The residue was purified by silica gel column chromatography, eluted with 0-50% ethyl acetate in petroleum ether to afford to afford a 1:1 mixture of (R,E)-3-(5-((tert-butyldiphenylsilyl)oxy)-3-methoxypent- 1 -en- 1 -yl)-2,6- dichloropyridine and (S,E)-3-(5-((tert-butyldiphenylsilyl)oxy)-3-methoxypent-l-en-l-yl)-2,6- dichloropyridine (21 g, 67%) as a yellow oil. MS ESI calculated for C27H3iChNO2Si [M+H]⁺, 500.15; found, 500.15.

[1563] A solution of tert-butyl carbamate (16.15 g, 137.85 mmol) and NaOH (5.51 g, 137.85 mmol) in propan-l-ol (125 mL) and H2O (125 mL) was stirred at 0 °C for 10 minutes, then DCDMH (27.16 g, 137.85 mmol) was added in portions over 2 min at 0 °C. After stirring at 0 °C for additional 30 minutes, (DHQ)2PHAL (supplier: Shanghai Accela ChemBio Co., Ltd. CAS# 140924-50-1) (3.58 g, 4.59 mmol), 1:1 mixture of (R,E)-3-(5- ((tert-butyldiphenylsilyl)oxy)-3-methoxypent-l-en-l-yl)-2,6-dichloropyridine and (S,E)-3-(5- ((tert-butyldiphenylsilyl)oxy)-3-methoxypent-l-en-l-yl)-2,6-dichloropyridine (21 g, 41.96 mmol) and Potassium osmate(VI) dihydrate (1.69 g, 4.59 mmol) were added to the mixture at 0 °C. The resulting mixture was stirred at 0 °C for additional 2 h. The reaction mixture was quenched with water and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under vacuum. The resulting residue was purified by silica gel column chromatography, eluted with 0-50% ethyl acetate in petroleum ether to afford a 1:1 mixture of tert-butyl ((lR*,2S*,3R)-5- ((tert-butyldiphenylsilyl)oxy)-l-(2,6-dichloropyridin-3-yl)-2-hydroxy-3- methoxypentyl)carbamate and tert-butyl ((lR*,2S*,3S)-5-((tert-butyldiphenylsilyl)oxy)-l- (2,6-dichloropyridin-3-yl)-2-hydroxy-3-methoxypentyl)carbamate (28.9 g, 99%) as a brown od. MS ESI calculated for Cs^CMWsSi [M+H]⁺, 633.22; found, 633.25.

Step-3:

[1564] To a solution of 1: 1 mixture of tert-butyl ((lR*,2S*,3R)-5-((tert- butyldiphenylsilyl)oxy)-l-(2,6-dichloropyridin-3-yl)-2-hydroxy-3-methoxypentyl)carbamate and tert-butyl ((lR*,2S*,3S)-5-((tert-butyldiphenylsilyl)oxy)-l-(2,6-dichloropyridin-3-yl)-2- hydroxy-3-methoxypentyl)carbamate (28.9 g, 45.71 mmol) in THF (289 mL) was added TBAF (17.89 g, 68.41 mmol) at room temperature. The resulting mixture was stirred at room temperature for additional 1 h. The solvents were removed under vacuum. The residue was purified by silica gel column chromatography, eluted with 0-30% ethyl acetate in petroleum ether to afford a 1:1 mixture of tert-butyl ((lR*,2S*,3R)-l-(2,6-dichloropyridin-3-yl)-2,5- dihydroxy-3-methoxypentyl)carbamate and tert-butyl ((lR*,2S*,3S)-l-(2,6-dichloropyridin- 3-yl)-2,5-dihydroxy-3-methoxypentyl)carbamate (8.8 g, 48%) as a yellow oil. MS ESI calculated for C16H24CI2N2O5 [M+H]⁺, 395.11; found, 395.10.

Step-4:

[1565] To a 1:1 mixture of tert-butyl ((lR*,2S*,3R)-l-(2,6-dichloropyridin-3-yl)-2,5- dihydroxy-3-methoxypentyl)carbamate and tert-butyl ((lR*,2S*,3S)-l-(2,6-dichloropyridin- 3-yl)-2,5-dihydroxy-3-methoxypentyl)carbamate (7.5 g, 18.97 mmol) in DCM (84 mL) was added EtaN (5.76 g, 56.92 mmol) at room temperature. Then MS2O (2.64 g, 15.17 mmol) was added dropwise at 0 °C. The resulting mixture was stirred at room temperature for additional 1 h. The reaction was quenched by water and extracted with dichloromethane. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under vacuum. The solvents were removed under vacuum. The residue was dissolved in DCM (84 mL), this was followed by the addition of trifluoroacetic acid (84 mL) at room temperature. The mixture was stirred at room temperature for 1 h. The solvents were removed under vacuum. The residue was dissolved in MeCN (153 mL), then 1,2,2,6,6-pentamethylpiperidine (56 g, 360.62 mmol) was added to the mixture at room temperature. The resulting mixture was stirred at 60 °C for 2 h. The reaction was quenched by water and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under vacuum to afford a 1 : 1 mixture of rel-(2R,3S,4R)-2-(2,6-dichloropyridin-3-yl)-4-methoxypiperidin-3-ol and rel-(2R,3S,4S)-2-(2,6-dichloropyridin-3-yl)-4-methoxypiperidin-3-ol (20 g) as a yellow semisolid. MS ESI calculated for C11H14CI2N2O2. [M+H]⁺, 277.15; found, 277.05.

Step-5:

[1566] To a solution of 1: 1 mixture of rel-(2R,3S,4R)-2-(2,6-dichloropyridin-3-yl)-4- methoxypiperidin-3-ol and rel-(2R,3S,4S)-2-(2,6-dichloropyridin-3-yl)-4-methoxypiperidin- 3-ol (7.8 g, 28.144 mmol) in methanol (78 mL) was added BOC2O (6.14 g, 28.144 mmol) at room temperature. The resulting mixture was stirred at room temperature for 1 h. The solvents were removed under vacuum. The residue was purified by normal phase flash column chromatography using a 330 g silica gel column eluted with 0-40% ethyl acetate in petroleum ether to afford a 1:1 mixture of rel-tert-butyl (2R,3S,4S)-2-(2,6-dichloropyridin-3- yl)-3-hydroxy-4-methoxypiperidine-l -carboxylate and rel-tert-butyl (2R,3S,4R)-2-(2,6- dichloropyridin-3-yl)-3-hydroxy-4-methoxypiperidine-l-carboxylate (2.8 g, 26%) as a yellow oil. MS ESI calculated for C16H22CI2N2O4. [M+H]⁺, 377.10; found, 377.15.

Step-6:

[1567] To a solution of 1: 1 mixture of rel-tert-butyl (2R,3S,4S)-2-(2,6-dichloropyridin-3- yl)-3-hydroxy-4-methoxypiperidine-l -carboxylate and rel-tert-butyl (2R,3S,4R)-2-(2,6- dichloropyridin-3-yl)-3-hydroxy-4-methoxypiperidine-l -carboxylate (2.7 g, 7.157 mmol) in tert-Amyl alcohol (108 rnL) was added t-BuOK (0.88 g, 7.873 mmol) at room temperature. The resulting mixture was stirred at room temperature for 3 h. The reaction mixture was quenched with water and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under vacuum. The residue was purified by normal phase flash column chromatography using a 120 g silica gel column eluted with 0-50% ethyl acetate in petroleum ether to afford rel-tert-butyl (4R,4aR,9bS)-7-chloro-4-methoxy-3,4,4a,9b-tetrahydrofuro[2,3-b:4,5-b']dipyridine-l(2H)- carboxylate isomer 2 (600 mg, 49%) as the first eluting peak. MS ESI calculated for C16H21CIN2O4. [M+H]⁺, 341.12; found, 341.15 [1568] The process also affords rel-tert-butyl (4R,4aS,9bR)-7-chloro-4-methoxy-3,4,4a,9b- tetrahydrofuro[2,3-b:4,5-b']dipyridine-l(2H)-carboxylate isomer 1 (600 mg, 49%) as a colorless oil as the second eluting peak. MS ESI calculated for C16H21CIN2O4. [M+H]⁺, 341.12; found, 341.15

Step-7:

[1569] To a stirred solution of rel-tert-butyl (4R,4aS,9bR)-7-chloro-4-methoxy-3,4,4a,9b- tetrahydrofuro[2,3-b:4,5-b']dipyridine-l(2H)-carboxylate isomer 1 (600 mg, 1.76 mmol) in ethyl acetate (115 mL) was added hydrogen chloride(4.0 M in ethyl acetate) (6 mL) at room temperature. The resulting mixture was stirred at room temperature for 2 h. The resulting mixture was concentrated under vacuum to afford rel-(4R,4aS,9bR)-7-chloro-4-methoxy- l,2,3,4,4a,9b-hexahydrofuro[2,3-b:4,5-b']dipyridine hydrochloride isomer 1 (A92 isomer 1) (335 mg) as a white solid. MS ESI calculated for C11H13CIN2O2. [M+H]⁺, 241.07; found, 241.10. NMR (400 MHz, DMSO-d₆) 5 10.40 (s, 1H), 8.61 (s, 1H), 7.99 (d, 7 = 7.8 Hz, 1H), 7.23 (d, J = 7.8 Hz, 1H), 5.11 (t, 7= 4.8 Hz, 1H), 5.01 (d, J = 5.6 Hz, 1H), 3.94 -

3.86 (m, 1H), 3.40 (s, 3H), 3.24 - 3.11 (m, 1H), 3.07 - 2.97 (m, 1H), 2.10 - 1.93 (m, 1H),

1.87 - 1.70 (m, 1H). Absolute stereochemistry was not determined.

Step-8:

[1570] To a stirred solution of rel-tert-butyl (4R,4aR,9bS)-7-chloro-4-methoxy-3,4,4a,9b- tetrahydrofuro[2,3-b:4,5-b']dipyridine-l(2H)-carboxylate isomer 2 (600 mg, 1.76 mmol) in ethyl acetate (115 mL) was added hydrogen chloride(4.0 M in ethyl acetate) (6 mL) at room temperature. The resulting mixture was stirred at room temperature for 2 h. The mixture was concentrated under vacuum to afford rel-(4R,4aR,9bS)-7-chloro-4-methoxy-l,2,3,4,4a,9b- hexahydrofuro[2,3-b:4,5-b']dipyridine hydrochloride isomer 2 (A92 isomer 2) (374 mg) as a white solid. MS ESI calculated for C11H13CIN2O2 [M+H]⁺, 241.07; found, 241.10. 'H NMR (400 MHz, DMSC i) 5 10.22 (s, 1H), 8.98 (s, 1H), 8.02 (d, J = 7.8 Hz, 1H), 7.24 (d, J = 7.8 Hz, 1H), 5.01 (d, J = 6.4 Hz, 1H), 4.92 - 4.81 (m, 1H), 3.92 - 3.91 (m, 1H), 3.41 (s, 3H), 3.08 - 3.06 (m, 2H), 2.01 - 1.91 (m, 2H). Absolute stereochemistry was not determined.

Intermediate A93 isomer 1: rel-(3aR,8bR)-6-(trifluoromethyl)-2,3,3a,8b-tetrahydro-lH- benzofuro[3,2-b]pyrrole isomer 1 isomer 1

Intennediate A93 isomer 2: rel-(3aR,8bR)-6-(trifluoromethyl)-2,3,3a,8b-tetrahydro-lH- benzofuro[3,2-b]pyrrole isomer 2 isomer 2

Step-1:

[1571] To a stirred solution of 2-hydroxy-4-(trifluoromethyl)benzaldehyde (5.0 g, 26.29 mmol) and ethyl propiolate (3.35 g, 34.18 mmol) in DCM (100 mL) was added NMM (532 mg, 5.26 mmol) dropwise at 0 °C under nitrogen atmosphere. The resulting mixture was stirred at room temperature for 16 h. The resulting mixture was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-30% ethyl acetate in petroleum ether to afford ethyl (E)-3-(2-formyl-5-

(trifluoromethyl)phenoxy)acrylate (5.8 g, 76%) as an off-white solid. MS ESI calculated for C13H11F3O4 [M+H]⁺, 289.06; found, 289.00.

Step-2:

[1572] A solution of 2-(perfluorophenyl)-6,7-dihydro-5H-pyrrolo[2,l-c][l,2,4]triazol-2- ium tetrafluoroborate (466 mg, 1.28 mmol) in THF (58 mL) was treated with TEA (129 mg, 1.28 mmol) at room temperature for 5 minutes, this was followed by a addition of ethyl 2-(3- oxo-6-(trifluoromethyl)-2,3-dihydrobenzofuran-2-yl)acetate (6.17 g, 21.40 mmol) in THF (116 mL) dropwise at room temperature. The resulting mixture was stirred at room temperature for 1 h. The reaction was quenched with NH4CI (aq.) at 0 °C. The resulting mixture was extracted with EtOAc. The organic layer was dried over anhydrous Na2SC>4.

After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-30% ethyl acetate in petroleum ether to afford a 1:1 mixture of ethyl (R)-2-(3-oxo-6-(trifluoromethyl)-2,3-dihydrobenzofuran-2- yl)acetate and ethyl (S)-2-(3-oxo-6-(trifluoromethyl)-2,3-dihydrobenzofuran-2-yl)acetate (4.7 g, 76%) as a colorless oil. MS ESI calculated for C13H11F3O4 [M+H]⁺, 289.06; found, 289.00.

Step-3:

[1573] To a stirred solution of 1: 1 mixture of ethyl (R)-2-(3-oxo-6-(trifluoromethyl)-2,3- dihydrobenzofuran-2-yl)acetate and ethyl (S)-2-(3-oxo-6-(trifluoromethyl)-2,3- dihydrobenzofuran-2-yl)acetate (6.3 g, 21.85 mmol) in EtOH (70 mL) were added hydroxylamine hydrochloride (3.04 g, 43.71 mmol) and AcONa (3.59 g, 43.71 mmol) at room temperature. The resulting mixture was stirred at 80 °C for 1 h. The mixture was allowed to cool down to room temperature. The mixture was filtered, and the filter cake was washed with EtOH. The filtrate was concentrated under reduced pressure. The residue was dissolved in EtOH (70 mL), and then Pd/C (10%, 500 mg) was added. The mixture was hydrogenated at room temperature for 16 h under hydrogen atmosphere. The reaction mixture was filtered through a Celite pad. The filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-15% methanol in dichloromethane to afford a 1:1 mixture of (3aS,8bS)-6-(trifhioromethyl)-l,3,3a,8b- tetrahydro-2H-benzofuro[3,2-b]pyrrol-2-one and (3aR,8bR)-6-(trifluoromethyl)-l,3,3a,8b- tetrahydro-2H-benzofuro[3,2-b]pyrrol-2-one (2.82 g, 53%) as an off-white solid. MS ESI calculated for CnH₈F₃NO2 [M+H]⁺, 244.05; found, 243.95.

Step-4:

A93 isomer 2

[1574] To a stirred solution of 1: 1 mixture of (3aS,8bS)-6-(trifluoromethyl)-l,3,3a,8b- tetrahydro-2H-benzofuro[3,2-b]pyrrol-2-one and (3aR,8bR)-6-(trifluoromethyl)-l,3,3a,8b- tetrahydro-2H-benzofuro[3,2-b]pyrrol-2-one (2.66 g, 10.93 mmol) in THF (30 mL) was added BH3-THF (IM in THF) (22 mL, 22 mmol) dropwise at 0 °C under nitrogen atmosphere. The resulting mixture was stirred at 70 °C for 16 h. The mixture was allowed to cool down to room temperature and quenched with MeOH at 0 °C. Then HC1 (cone., 15 mL) was added the mixture at room temperature. The resulting mixture was stirred at 70 °C for 16 h. The mixture was allowed to cool down to room temperature and concentrated under reduced pressure. The residue was quenched with water and extracted with ethyl acetate. The aqueous layer was collected and basified with saturated NaHCCh (aq.) to pH 8. The resulting mixture was extracted with EtOAc. The organic layer was dried over anhydrous NaiSCX After filtration, the filtrate was concentrated under reduced pressure to afford a 1: 1 mixture of (3aS,8bS)-6-(trifhioromethyl)-2,3,3a,8b-tetrahydro-lH-benzofuro[3,2-b]pyrrole and (3aR,8bR)-6-(trifhioromethyl)-2,3,3a,8b-tetrahydro-lH-benzofuro[3,2-b]pyrrole (1.86 g) as a brown solid.

[1575] The 1:1 mixture of (3aS,8bS)-6-(trifhioromethyl)-l,3,3a,8b-tetrahydro-2H- benzofuro[3,2-b]pyrrol-2-one and (3aR,8bR)-6-(trifluoromethyl)- 1 ,3,3a,8b-tetrahydro-2H- benzofuro[3,2-b]pyrrol-2-one (1.86 g) was separated by prep-chiral HPLC with the following conditions [Column: CHIRALPAK IG, 5*25 cm, 10 pm; Mobile Phase A: Hex— HPLC, Mobile Phase B: EtOH: DCM=1: 1; Flow rate: 100 mL/min; Gradient (B%): isocratic 10% B; Wave Length: 220 nm; RTl(min): 10.9; RT2(min): 15; Sample Solvent: EtOH— HPLC; Injection Volume: 10 mL] to afford rel-(3aR,8bR)-6-(trifluoromethyl)-2,3,3a,8b-tetrahydro- lH-benzofuro[3,2-b]pyrrole (A93, isomer 1) (1.1 g, 62%) as a brown solid as the first peak on chiral HPLC. MS ESI calculated for C11H10F3NO [M+H]⁺, 230.07; found, 230.05. 'H NMR (400 MHz, CDCW) 57.42 (d, J= 7.6 Hz, 1H), 7.23 - 6.91 (m, 2H), 5.37 (t, J= 6.4 Hz, 1H), 5.04 (d, J = 6.4 Hz, 1H), 3.15 - 3.08 (m, 1H), 2.75 - 2.66 (m, 1H), 2.29 - 2.22 (m, 1H), 2.02 - 1.92 (m, 1H). Absolute stereochemistry was not determined.

[1576] The separation also affords rel-(2R,6R)-10-(trifluoromethyl)-7-oxa-3- azatricyclo[6.4.0.0^A{2,6}]dodeca-l(12),8,10-triene (A93, isomer 2) (1.4 g, 79%) as a brown solid as the second peak on chiral HPLC. MS ESI calculated for C11H10F3NO [M+H]⁺, 230.07; found, 230.05. 'H NMR (400 MHz, CDCWi) 5 7.44 (d, 7 = 7.6 Hz, 1H), 7.24 - 6.94 (m, 2H), 5.37 (t, J = 6.4 Hz, 1H), 5.05 (d, J = 6.4 Hz, 1H), 3.16 - 3.10 (m, 1H), 2.75 - 2.65 (m, 1H), 2.29 - 2.23 (m, 1H), 2.04 - 1.93 (m, 1H). Absolute stereochemistry was not determined.

Intermediate A94: (3R,4aS,9bS)-3-methoxy-7-(trifluoromethyl)-l,2,3,4,4a,9b- hexahydrofuro[2,3-b:4,5-b']dipyridine

Step 1:

[1577] To a stirred solution of ethynyltrimethylsilane (50.00g, 509.06 mmol) in THF (300 mL) were added n-BuLi (2.5M in hexane) (203 mL, 507.5 mmol) dropwise at -78°C under nitrogen atmosphere. After stirring at -78 °C for 1 hour under nitrogen atmosphere, Boron trifluoride diethyl etherate (48.17 g, 339.37 mmol) was added dropwise at -78 °C, this was followed by the additon of a solution of (R)-tert-butyldimethyl(oxiran-2-ylmethoxy)silane (supplier: Shanghai Haohong Scientific Co., Ltd. CAS# 124150-87-4 ) (31.96 g, 169.69 mmol) in THF (50 mL) dropwise at -78 °C. The resulting mixture was stirred at room temperature overnight. The reaction was quenched with NH4CI (aq.) at room temperature and extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous NaiSCL. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-10% ethyl acetate in petroleum ether to afford (R)-l-((tert-butyldimethylsilyl)oxy)-5-(trimethylsilyl)pent-4-yn-2- ol (37.5 g, 69%) as a brown oil. MS ESI calculated for CuHaoChSi? [M+H]⁺, 287.18 ; found, 287.18.

Step 2:

[1578] To a stirred solution of (R)-l-((tert-butyldimethylsilyl)oxy)-5-(trimethylsilyl)pent- 4-yn-2-ol (135.00 g, 471.10 mmol) and Nl,Nl,N8,N8-tetramethylnaphthalene-l,8-diamine (302.89 g, 1413.31 mmol) in DCM (700 mL) were added trimethyloxonium tetrafluoroborate (174.20 g, 1177.74 mmol) dropwise at room temperature under nitrogen atmosphere. The resulting mixture was stirred at room temperature overnight. The resulting mixture was filtered, the filter cake was washed with DCM. The filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-10% ethyl acetate in petroleum ether to afford (R)-tert-butyl((2-methoxy-5-(trimethylsilyl)pent-4- yn-l-yl)oxy)dimethylsilane (210.00 g, 74%) as a yellow oil. MS ESI calculated for Ci₅H₃2O2Si2 [M+H]⁺, 301.19; found, 301.19.

Step 3:

[1579] To a stirred solution of (R)-tert-butyl((2-methoxy-5-(trimethylsilyl)pent-4-yn-l- yl)oxy)dimethylsilane (240.00 g, 798.43 mmol) in methanol (1500 mL) was added K2CO3 (220.69 g, 1596.86 mmol) at room temperature under nitrogen atmosphere. The resulting mixture was stirred at room temperature overnight. The resulting mixture was filtered, the filter cake was washed with methanol. The filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-10% ethyl acetate in petroleinn ether to afford (R)-tert-butyl((2-methoxypent-4-yn-l- yl)oxy)dimethylsilane (180.00 g, 98%) as a yellow oil. MS ESI calculated for Ci2H24O2Si [M+H]⁺, 229.15 ; found, 229.15.

Step 4:

[1580] To a mixture of (R)-tert-butyl((2-methoxypent-4-yn-l-yl)oxy)dimethylsilane (180.00 g, 788.07 mmol) and 4,4,5,5-tetramethyl-l,3,2-dioxaborolane (151.29 g, 1182.10 mmol) was added bis(cyclopenta-l,3-dien-l-yl)zirconiumbis(ylium) chloride hydride (20.24 g, 78.81 mmol) at 0 °C, this was followed by the addition of Et₃N (7.97 g, 78.81 mmol) dropwises at 0 °C. The mixture was heated to 60 °C for 16 h with stirring. The reaction was quenched by water and extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SO₄. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-20% ethyl acetate in petroleum ether to afford (R,E)-tert-butyl((2-methoxy-5-(4,4,5,5- tetramethyl-l,3,2-dioxaborolan-2-yl)pent-4-en-l-yl)oxy)dimethylsilane (110 g, 39%) as a brown oil. MS ESI calculated for Ci₈H₃₇BO₄Si [M+H]⁺, 357.26 ; found, 357.26.

Step 5:

[1581] To a stirred solution of (R,E)-tert-butyl((2-methoxy-5-(4,4,5,5-tetramethyl-l,3,2- dioxaborolan-2-yl)pent-4-en-l-yl)oxy)dimethylsilane (62.00 g, 173.97 mmol) and 3-bromo- 2-chloro-6-(trifluoromethyl)pyridine (45.31 g, 173.97 mmol) in Dioxane (600 mL) and H2O (60 mL) were added K2CO3 (72.13 g, 521.90 mmol) and Pd(dppf)Cl₂ (12.73 g, 17.39 mmol) at room temperature under nitrogen atmosphere. The resulting mixture was heated to 100 °C with stirring for 16 h. The mixture was allowed to cool down to room temperature. The resulting mixture was quenched with water and extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SO₄. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-20% ethyl acetate in petroleum ether to afford (R,E)-3-(5- ((tert-butyldimethylsilyl)oxy)-4-methoxypent- 1 -en- 1 -yl)-2-chloro-6-(trifluoromethyl)pyridine (58.4 g, 81%) as a brown oil. MS ESI calculated for Ci8H27ClF₃NO₂Si [M+H]⁺, 410.15 ; found, 410.15.

Step 6:

[1582] To a stirred solution of NaOH (14.75 g, 368.83 mmol) in H2O (922 mL) was added a solution of tert-butyl carbamate (49.61 g, 423.47 mmol) in propan-l-ol (1058 mL), then l,3-dichloro-5,5-dimethylimidazolidine-2, 4-dione (53.83 g, 273.20 mmol) was added in portions at room temperature under nitrogen atmosphere. After stirring at room temperature for 0.5 hour, a solution of (DHQ)2PHAL (supplier: Shanghai Accela ChemBio Co., Ltd. CAS# 140924-50-1) (10.64 g, 13.66 mmol) in propan-l-ol (137 mL) and a solution of (R,E)- 3-(5-((tert-butyldimethylsilyl)oxy)-4-methoxypent- 1 -en- 1 -yl)-2-chloro-6- (trifhioromethyl)pyridine (56.00 g, 136.60 mmol) in propan-l-ol (137 mL) was added at 0 °C, after that, Potassium osmate(VI) dihydrate (5.03 g, 13.660 mmol) was added in portions at 0 °C. The resulting mixture was stirred at room temperature overnight. The reaction mixture was concentrated under reduced pressure. The residue was dissolved in H2O and extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SC>4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-20% ethyl acetate in petroleum ether to afford a 1:8 mixture of tert-butyl ((lR,2R,4R)-5-((tert- butyldimethylsilyl)oxy)-l-(2-chloro-6-(trifluoromethyl)pyridin-3-yl)-2-hydroxy-4- methoxypentyl)carbamate and tert-butyl ((lS,2S,4R)-5-((tert-butyldimethylsilyl)oxy)-l-(2- chloro-6-(trifhioromethyl)pyridin-3-yl)-2-hydroxy-4-methoxypentyl)carbamate (49.8 g, 67%) as a yellow oil. MS ESI calculated for C23H3sClF3N2O5Si [M+H]⁺, 543.22 ; found, 543.25.

Step 7: [1583] A mixture of 1:8 mixture of tert-butyl ((lR,2R,4R)-5-((tert-butyldimethylsilyl)oxy)- 1 -(2-chloro-6-(trifluoromethyl)pyridin-3-yl)-2-hydroxy-4-methoxypentyl)carbamate and tertbutyl ((lS,2S,4R)-5-((tert-butyldimethylsilyl)oxy)-l-(2-chloro-6-(trifluoromethyl)pyridin-3- yl)-2-hydroxy-4-methoxypentyl)carbamate (20 g, 36.82 mmol), Pd(OAc)2 (1.65 g, 7.36 mmol), CS2CO3 (36.00 g, 110.47 mmol) and JohnPhos (2.2 g, 7.36 mmol) in Toluene (50 mL) was stirred at 100 °C for 16 h under nitrogen atmosphere. The resulting mixture was concentrated under reduced pressure. The residue was quenched with water and extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SC>4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-20% ethyl acetate in petroleum ether to afford a 1:8 mixture of tert-butyl ((2R,3R)-2-((R)-3-((tert- butyldimethylsilyl)oxy)-2-methoxypropyl)-6-(trifluoromethyl)-2,3-dihydrofuro[2,3- b]pyridin-3-yl)carbamate and tert-butyl ((2S,3S)-2-((R)-3-((tert-butyldimethylsilyl)oxy)-2- methoxypropyl)-6-(trifluoromethyl)-2,3-dihydrofuro[2,3-b]pyridin-3-yl)carbamate (11 g, 58% yield) as a yellow oil. MS ESI calculated for C23H37F3N2OsSi [M+H]⁺, 507.24 ; found, 507.15.

Step 7:

[1584] To a solution of 1:8 mixture of tert-butyl ((2R,3R)-2-((R)-3-((tert- butyldimethylsilyl)oxy)-2-methoxypropyl)-6-(trifluoromethyl)-2,3-dihydrofuro[2,3- b]pyridin-3-yl)carbamate and tert-butyl ((2S,3S)-2-((R)-3-((tert-butyldimethylsilyl)oxy)-2- methoxypropyl)-6-(trifluoromethyl)-2,3-dihydrofuro[2,3-b]pyridin-3-yl)carbamate (23.00 g, 45.40 mmol) in THF (300 mL) was added TBAF (23.74 g, 90.79 mmol) at room temperature. The resulting mixture was stirred at room temperature for 2 hours. The mixture was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-20% ethyl acetate in petroleum ether to afford a 1:8 mixture of tert-butyl ((2R,3R)-2-((R)-3-hydroxy-2-methoxypropyl)-6-(trifluoromethyl)-2,3- dihydrofuro[2,3-b]pyridin-3-yl)carbamate and tert-butyl ((2S,3S)-2-((R)-3-hydroxy-2- methoxypropyl)-6-(trifluoromethyl)-2,3-dihydrofuro[2,3-b]pyridin-3-yl)carbamate (17.00 g, 95%) as a brown oil. MS ESI calculated for C17H23F3N2O5 [M+H]⁺, 393.16 ; found, 393.05.

Step 8:

[1585] To a solution of 1:8 mixture of tert-butyl ((2R,3R)-2-((R)- 3-hydroxy-2- methoxypropyl)-6-(trifluoromethyl)-2,3-dihydrofuro[2,3-b]pyridin-3-yl)carbamate and tertbutyl ((2S,3S)-2-((R)-3-hydroxy-2-methoxypropyl)-6-(trifluoromethyl)-2,3-dihydrofuro[2,3- b]pyridin-3-yl)carbamate (17.00 g, 45.87 mmol) in Toluene (200 mL) was added 2-(tributyl- X⁵-phosphaneylidene)acetonitrile (CAS No. 157141-27-0) (22.14 g, 91.75 mmol) at room temperature. The mixture was heated to 110 °C for 16 h with stirring. The mixture was allowed to cool down to room temperature. The resulting mixture was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-20% ethyl acetate in petroleum ether to afford a 1:8 mixture of tert-butyl (3R,4aR,9bR)-3- methoxy-7-(trifhioromethyl)-3,4,4a,9b-tetrahydrofuro[2,3-b:4,5-b']dipyridine-l(2H)- carboxylate and tert-butyl (3R,4aS,9bS)-3-methoxy-7-(trifhioromethyl)-3,4,4a,9b- tetrahydrofuro[2,3-b:4,5-b']dipyridine-l(2H)-carboxylate (15.1 g, 72%) as a brown oil. MS ESI calculated for C17H21F3N2O4 [M+H]⁺, 375.15 ; found, 375.15.

Step 9:

[1586] A 1:8 mixture of tert-butyl (3R,4aR,9bR)-3-methoxy-7-(trifluoromethyl)-3,4,4a,9b- tetrahydrofuro[2,3-b:4,5-b']dipyridine-l (2H)-carboxylate and tert-butyl (3R,4aS,9bS)-3- methoxy-7-(trifhioromethyl)-3,4,4a,9b-tetrahydrofuro[2,3-b:4,5-b']dipyridine-l(2H)- carboxylate (15.1 g, 40.33 mmol) and HC1 (g) (4.0 M in 1,4-dioxane, 150 mL) was stirred at room temperature for 1 hour. The resulting mixture was concentrated under reduced pressure. The resude was purified by Prep-Chiral SFC with the following conditions (Column: CHIRALPAK AD-H, 5*25 cm, 5 pm; Mobile Phase A: CO₂, Mobile Phase B: MEOH; Flow rate: 180 mL/min; Gradient (B%): isocratic 40% B; Wave Length: 220 nm; RTl(min): 3.25; RT2(min): 6.35; Sample Solvent: MEOH) to afford (3R,4aS,9bS)-3-methoxy-7- (trifluoromethyl)-l,2,3,4,4a,9b-hexahydrofuro[2,3-b:4,5-b']dipyridine (A94) (8.4 g, 79%) as a brown solid with retention time at 6.35 minute. MS ESI calculated for C12H13F3N2O2 [M+H]⁺, 275.09; found, 275.05. 'H NMR (300 MHz, DMSO) 57.95 (d, J = 7.4 Hz, 1H), 7.44 (d, 7 = 7.4 Hz, 1H), 4.85 - 4.80 (m, 1H), 4.61 (d, 7 = 7.2 Hz, 1H), 3.40 - 3.31 (m, 1H), 3.21 (s, 3H), 2.99 - 2.92 (m, 1H), 2.47 (d, J = 6.2 Hz, 1H), 2.33 - 2.25 (m, 1H), 1.92 - 1.80 (m, 1H). Absolute stereochemistry was determined by NOESY.

Intermediate A95: rel-(4aR,9bR)-7-(difluoromethyl)-l,2,3,4,4a,9b-hexahydrofuro[2,3-b:4,5- b']dipyridine

Step-1:

[1587] To a stirred mixture of methyl 5-bromo-6-chloropicolinate (25.00 g, 99.81 mmol) and CaCh (16.62 g, 149.71 mmol) in THF (200 mL) and EtOH (200 mL) was added NaBFU (9.44 g, 249.52 mmol) in portions at room temperature under nitrogen atmosphere. The resulting mixture was stirred at room temperature overnight under nitrogen atmosphere. The reaction was quenched with ice water and extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SC>4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with PE/EtOAc (5/ 1) to afford (5-bromo-6-chloropyridin-2- yl)methanol (20.00 g, 90% yield) as a white solid. MS ESI calculated for CgHsBrClNO [M+H]⁺, 221.92, 223.92; found, 221.90, 223.90.

Step-2:

[1588] To a stirred solution of (5-bromo-6-chloropyridin-2-yl)methanol (20.00 g, 89.90 mmol) in DCM (200 mL) was added MnCh (78.16 g, 899.00 mmol) in portions at room temperature. The resulting mixture was stirred at room temperature overnight. The mixture was filtered, the filter cake was washed with DCM. The filtrate was concentrated under reduced pressure. This resulted in 5-bromo-6-chloropicolinaldehyde (17.00 g, 85% yield) as an off-white solid. MS ESI calculated for CeftBrClNO [M+H]⁺, 219.91, 221.91; found, 219.90, 221.90.

Step-3:

[1589] To a stirred solution of 5-bromo-6-chloropicolinaldehyde (17.00 g, 77.12 mmol) in DCM (150 mL) was added Diethylaminosulfur trifluoride (24.86 g, 154.23 mmol) dropwise at 0 °C under nitrogen atmosphere. The resulting mixture was stirred at room temperature for 2 h. The reaction was quenched with ice water at 0 °C. The mixture was basified with NaHCCh (sat.) to pH 7. The mixture was extracted with CH2CI2. The combined organic layers were washed with brine, dried over anhydrous Na2SO4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with PE/EtOAc (5/1) to afford 3-bromo-2-chloro-6- (difluoromethyl)pyridine (15.00 g, 80.2% yield) as a light yellow oil. MS ESI calculated for C6H₃BrClF2N [M+H]⁺, 241.91, 243.91; found, 241.90, 243.90.

Step-4:

[1590] To a stirred mixture of 3-bromo-2-chloro-6-(difluoromethyl)pyridine (11.00 g, 45.37 mmol) and (E)-tert-butyldiphenyl((5-(4,4,5,5-tetramethyl-l,3,2-dioxaborolan-2- yl)pent-4-en-l-yl)oxy)silane (30.66 g, 68.06 mmol) in Dioxane (150 mL) and H2O (15 mL) were added Pd(dppf)Ch-CH2C12 (3.70 g, 4.54 mmol) and K2CO3 (18.81 g, 136.11 mmol) at room temperature under nitrogen atmosphere. The resulting mixture was heated to 100 °C with stirring for 16 h. The reaction mixture was quenched with water and extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SC>4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with PE/EtOAc (1/1) to afford (E)-3-(5-((tert- butyldiphenylsilyl)oxy)pent-l-en-l-yl)-2-chloro-6-(difluoromethyl)pyridine (20.00 g, 90% yield) as a light yellow oil. MS ESI calculated for C27H3oClF2NOSi [M+H]⁺, 486.18, 488.18; found, 486.15, 488.15.

Step-5:

[1591] To a stirred solution of NH2B0C (14.94 g, 127.55 mmol) in propan-l-ol (212 mL) were added a solution of NaOH (4.44 g, 111.09 mmol) in H2O (185 mL). After stirring at 0 °C for 30 minutes, DCDMH (12.16 g, 61.72 mmol) was added in portions at room temperature. This was followed by the addition of (DHQ)2PHAL (supplier: Shanghai Accela ChemBio Co., Ltd. CAS# 140924-50-1) (3.21 g, 4.12 mmol) in propan-l-ol (55 mL), a solution of (E)-3-(5-((tert-butyldiphenylsilyl)oxy)pent- 1 -en- 1 -yl)-2-chloro-6- (difluoromethyl)pyridine (20.00 g, 41.15 mmol) in propan-l-ol (20 mL) and Potassium osmate(VI) dihydrate (1.52 g, 4.12 mmol) at 0 °C. The resulting mixture was stirred at room temperature for 16 h. The mixture was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with PE/EtOAc (1/1) to afford rel-tert- butyl ((lR,2R)-5-((tert-butyldiphenylsilyl)oxy)-l-(2-chloro-6-(difhioromethyl)pyridin-3-yl)- 2-hydroxypentyl)carbamate (30.00 g, crude) as a green semi-solid. MS ESI calculated for C32H₄iClF2N₂O4Si [M+H]⁺, 619.25; found, 619.20.

Step-6:

[1592] To a stirred mixture of rel-tert-butyl ((lR,2R)-5-((tert-butyldiphenylsilyl)oxy)-l-(2- chloro-6-(difluoromethyl)pyridin-3-yl)-2-hydroxypentyl)carbamate (30.00 g, 48.45 mmol) and CS2CO3 (47.36 g, 145.34 mmol) in toluene (300 mL) were added JohnPhos (2.17 g, 7.27 mmol) and Pd(OAc)2 (1.09 g, 4.85 mmol) at room temperature under nitrogen atmosphere. The resulting mixture was stirred at 90 °C overnight. The resulting mixture was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with PE/EtOAc (5/1) to afford rel-tert-butyl ((2R,3R)-2-(3-((tert- butyldiphenylsilyl)oxy)propyl)-6-(difluoromethyl)-2,3-dihydrofuro[2,3-b]pyridin-3- yl)carbamate (10.00 g, 41% over 2 steps) as a light brown oil. MS ESI calculated for C32H₄oF₂N204Si [M+H]⁺, 583.27; found, 583.25.

Step 7:

[1593] To a stirred solution of rel-tert-butyl ((2R,3R)-2-(3-((tert- butyldiphenylsilyl)oxy)propyl)-6-(difhioromethyl)-2,3-dihydrofuro[2,3-b]pyridin-3- yl)carbamate (10.00 g, 17.16 mmol) in THF (100 mL) was added TBAF (8.97 g, 34.32 mmol) at room temperature. The resulting mixture was stirred at room temperature overnight. The mixture was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with PE/EtOAc (1/1) to afford rel-tert-butyl ((2R,3R)-6- (difluoromethyl)-2-(3-hydroxypropyl)-2,3-dihydrofuro[2,3-b]pyridin-3-yl)carbamate (4.00 g, 67% yield) as a light-yellow solid. MS (ESI) calculated for C16H22F2N2O4 [M+H]⁺, 345.15; found, 345.10.

Step 8:

[1594] To a stirred solution of rel-tert-butyl ((2R,3R)-6-(difluoromethyl)-2-(3- hydroxypropyl)-2,3-dihydrofuro[2,3-b]pyridin-3-yl)carbamate (4.00 g, 11 -62 mmol) in toluene (50 mL) was added 2-(tributyl-k⁵-phosphancylidcnc)acctonitrilc (CAS No. 157141- 27-0) (5.61 g, 23.23 mmol) at room temperature under nitrogen atmosphere. The mixture was stirred at 100 °C overnight. The resulting mixture was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with PE/EtOAc (1/1) to afford rel-tert-butyl (4aR,9bR)-7-(difluoromethyl)-3,4,4a,9b-tetrahydrofuro[2,3-b:4,5- b']dipyridine-l(2H)-carboxylate (2.50 g, 65% yield) as a tight yellow solid. MS (ESI) calculated for C16H20F2N2O3 [M+H]⁺, 327.14; found, 327.10.

Step 9:

[1595] A solution of rel-tert-butyl (4aR,9bR)-7-(difluoromethyl)-3,4,4a,9b- tetrahydrofuro[2,3-b:4,5-b']dipyridine-l(2H)-carboxylate (2.50 g, 7.66 mmol) and HC1 (4M in dioxane) (30 mL) was stirred at room temperature for 1 h. The resulting mixture was concentrated under reduced pressure. The crude product was purified by Prep-Chiral-SFC with the following conditions (Column: CHIRALPAK IF 3*25 cm, 5 pm; Mobile Phase A: CO2, Mobile Phase B: MEOH; Flow rate: 100 mL/min; Gradient (B%): isocratic 50% B; Back Pressure(bar): 100; Wave Length: 220 nm; RTl(min): 2.1; RT2(min): 3.32; Sample Solvent: MEOH) to afford rel-(4aR,9bR)-7-(difluoromethyl)-l,2,3,4,4a,9b- hexahydrofuro[2,3-b:4,5-b']dipyridine (1.00 g, 57% yield) as a yellow oil with retention time at 3.32 minute. MS ESI calculated for C11H12F2N2O [M+H]⁺, 227.09; found, 227.01. 'H NMR (300 MHz, DMSO) 8 7.82 (d, J = 7.2 Hz, 1H), 7.21 (d, J = 7.2 Hz, 1H), 6.81 (t, J = 55.0 Hz, 1H), 4.66 - 4.55 (m, 1H), 4.35 (d, J = 6.0 Hz, 1H), 2.83 (br, 1H), 2.70 - 2.52 (m, 2H), 2.01 - 1.89 (m, 2H), 1.55 - 1.38 (m, 2H). Absolute stereochemistry was not determined.

Intermediate A96: (4aS,9bS)-7-(trifluoromethoxy)-l,2,3,4,4a,9b-hexahydrofuro[2,3-b:4,5- b']dipyridine

A96

Step-1:

[1596] To a stirred solution of LDA (2.0 M in THF, 14 mL) in THF (84 mL) was added a solution of 2-chloro-6-(trifluoromethoxy)pyridine (5.00 g, 25.31 mmol) in THF (5 mL) at -78 °C under nitrogen atmosphere. After stirring at -78 °C for 1.5 h, a solution of TMSC1 (3.02 g, 27.84 mmol) in THF (28 mL) was added dropwise at -78 °C. The resulting mixture was stirred at room temperature for 16 h. The reaction was poured into water at room temperature and extracted with CH2CI2. The combined organic layers were washed with brine, dried over anhydrous Na2SC>4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-3% EtOAc in PE to afford 6-chloro-2-(trifhioromethoxy)-3-(trimethylsilyl)pyridine (4.91 g, 71%) as a colorless liquid. MS ESI calculated for C₉HiiClF₃NOSi [M+H]⁺, 270.03; found, 270.00.

Step-2:

[1597] To a stirred mixture of LDA (2.0 M in THF, 10 mL) in THF (70 mL) was added a solution of 6-chloro-2-(trifhioromethoxy)-3-(trimethylsilyl)pyridine (4.70 g, 17.42 mmol) in THF (24 mL) dropwise at -78 °C under nitrogen atmosphere. After stirring at -78 °C for 2 h, a solution of I2 (4.87 g, 19.16 mmol) in THF (24 mL) was added dropwise at -78 °C. The resulting mixture was stirred at room temperature for additional 16 h. The reaction was poured into NH4CI (sat.) at room temperature. The resulting mixture was extracted with CH2CI2. The combined organic layers were washed with brine, dried over anhydrous Na2SC>4. After filtration, the filtrate was concentrated under reduced pressure to afford 2-chloro-3- iodo-6-(trifhioromethoxy)-5-(trimethylsilyl)pyridine (8.23 g, crude) as a brown oil. MS ESI calculated for C₉HioClF₃INOSi [M+H]⁺, 395.92; found, 395.80.

Step-3: [1598] To a stirred mixture of 2-chloro-3-iodo-6-(trifluoromethoxy)-5- (trimethylsilyl)pyridine (8.23 g, 20.80 mmol) in THF (80 mL) was added TBAF (10.88 g, 41.60 mmol) at room temperature under nitrogen atmosphere. The resulting mixture was stirred at room temperature for 2 h. The reaction was quenched by water and extracted with CH2CI2. The combined organic layers were washed with brine, dried over anhydrous Na2SC>4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with PE to afford 2-chloro-3-iodo-6- (trifluoromethoxy)pyridine (3.82 g, 56%) as a white solid. MS ESI calculated for C6H2CIF3INO [M+H]⁺, 323.88; found, 323.85.

Step-4:

[1599] To a stirred mixture of 2-chloro-3-iodo-6-(trifhioromethoxy)pyridine (3.0 g, 9.27 mmol) and tert-butyl 3-oxopiperidine-l -carboxylate (2.77 g, 13.91 mmol) in toluene (30 mL) were added K3PO4 (4.73 g, 22.26 mmol) and Pd(t-BusP)2 (0.33 g, 0.64 mmol) at room temperature under nitrogen atmosphere. The resulting mixture was stirred at 80 °C for 2 h. The mixture was allowed to cool down to room temperature. The mixture was filtered, the filter cake was washed with EtOAc. The filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-20% EtOAc in PE to afford tert-butyl 2-(2-chloro-6-(trifhioromethoxy)pyridin-3-yl)-3-oxopiperidine-l- carboxylate (1.70 g, 46%) as a yellow oil. MS ESI calculated for C16H18CIF3N2O4 [M+H]⁺, 395.09; found, 395.00.

Step-5: [1600] To a stirred mixture of tert-butyl 2-(2-chloro-6-(trifluoromethoxy)pyridin-3-yl)-3- oxopiperidine-1 -carboxylate (1.70 g, 4.30 mmol) and DABCO (2.61 g, 23.25 mmol) in MeCN (40 mL) was added HCOOH (0.59 g, 12.91 mmol) and RuCl(p-cymene)[(S,S)-Ts- DPEN] (0.08 g, 0.13 mmol) at 0 °C under nitrogen atmosphere. The resulting mixture was stirred at room temperature for 16 h. The mixture was basified with saturated NaHCCh (aq.) to pH 8. The mixture was extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SO4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-28% EtOAc in PE to afford tert-butyl (2S,3S)-2-(2-chloro-6-(trifluoromethoxy)pyridin-3- yl)-3-hydroxypiperidine-l-carboxylate (1.37 g, 80%) as a yellow oil. MS ESI calculated for C16H20CIF3N2O4 [M+H]⁺, 397.11; found, 397.05.

Step-6:

[1601] To a stirred mixture of tert-butyl (2S,3S)-2-(2-chloro-6-(trifluoromethoxy)pyridin- 3-yl)-3-hydroxypiperidine-l -carboxylate (1.25 g, 3.15 mmol) in THF (30 mL) was added t- BuOK (0.53 g, 4.72 mmol) at room temperature under nitrogen atmosphere. The resulting mixture was stirred at 70 °C for 2 h. The reaction was allowed to cool down to room temperature and quenched with NH4CI (sat.). The resulting mixture was extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous NaiSC After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-24% EtOAc in PE to afford tert-butyl (4aS,9bS)-7-(trifhioromethoxy)-3,4,4a,9b-tetrahydrofuro[2,3-b:4,5-b']dipyridine-l(2H)- carboxylate (0.83 g, 73%) as a white solid. MS ESI calculated for C16H19F3N2O4 [M+H]⁺, 361.13; found, 361.10.

Step-7:

[1602] To a stirred mixture of tert-butyl (4aS,9bS)-7-(trifluoromethoxy)-3,4,4a,9b- tetrahydrofuro[2,3-b:4,5-b']dipyridine-l(2H)-carboxylate (830 mg, 2.30 mmol) in EtOAc (4 mL) was added HC1 (4 M in 1,4-dioxane, 12 mL) at room temperature. The resulting mixture was stirred at room temperature for 4 h. The resulting mixture was concentrated under reduced pressure to afford (4aS,9bS)-7-(trifluoromethoxy)-l,2,3,4,4a,9b-hexahydrofuro[2,3- b:4,5-b']dipyridine hydrochloride (A96) (550 mg, 91%) as a white solid. MS ESI calculated for C11H11F3N2O2 [M+H]⁺, 261.08; found, 261.00. 'H NMR (400 MHz, DMSO-d₆) 8 10.77 (br, 1H), 8.83 (br, 1H), 5 8.20 (d, J = 8.0 Hz, 1H), 6.95 (d, J = 8.0 Hz, 1H), 4.99 - 4.88 (m, 2H), 3.14 - 3.09 (m, 1H), 2.96 - 2.89 (m, 1H), 2.25 - 2.20 (m, 1H), 2.12 - 1.71 (m, 1H), 1.78 - 1.71 (m, 2H).

Intermediate A97 : (3R,4aR*, 10bR*)-3-methoxy-8-(trifluoromethyl)-2,3,4,4a,6,l Ob- hexahydro- 1 H-pyrano [3 ,2-b : 5 ,4-b '] dipyridine

A97

Step-1:

[1603] To a stirred solution of (R,E)-tert-butyl((2-methoxy-5-(4,4,5,5-tetramethyl-l,3,2- dioxaborolan-2-yl)pent-4-en-l-yl)oxy)dimethylsilane (20.0 g, 56.75 mmol) in dioxane (200 mL) and H2O (20 mL) were added ethyl 3-bromo-6-(trifluoromethyl)pyridine-2-carboxylate (25.37 g, 85.12 mmol), Pd(dppf)Cl₂ (4.15 g, 5.68 mmol) and K2CO3 (23.53 g, 170.24 mmol) at 25 °C. The resulting solution was stirred at 100 °C for 2 h. The solvents were removed under vacuum. The residue was purified by silica gel column chromatography, eluted with 0 ~ 40% EtOAc in petroleum ether to afford ethyl (R,E)-3-(5-((tert-butyldimethylsilyl)oxy)-4- methoxypent-l-en-l-yl)-6-(trifluoromethyl)picolinate (9.0 g, 35%) as a yellow oil. MS ESI calculated for C₂iH₃₂F₃NO4Si [M+H]⁺, 448.21; found, 448.20.

Step-2:

[1604] To a stirred solution of NH₂Boc (7.55 g, 64.42 mmol) in i-PrOH (194 mL) was added a solution of NaOH (2.24 g, 56.10 mmol) in H₂O (69 mL) at 25 °C. The resulting solution was stirred at 25 °C for 10 minutes, then l,3-dichloro-5,5-dimethylimidazolidine- 2, 4-dione (4.91 g, 24.94 mmol) was added at 25 °C. After stirring at 25 °C for 30 minutes, a solution of (DHQ)2PHAL (supplier: Shanghai Accela ChemBio Co., Ltd. CAS# 140924-50- 1) (1.62 g, 2.08 mmol) in i-PrOH (194 mL), a solution of ethyl (R,E)-3-(5-((tert- butyldimethylsilyl)oxy)-4-methoxypent- 1 -en- 1 -yl)-6-(trifhioromethyl)picolinate (9.30 g, 20.78 mmol) in i-PrOH (194 mL) and Potassium osmate(VI) dihydrate (0.77 g, 2.08 mmol) were added at 0 °C. The mixture was stirred at 25 °C for 16 h. The reaction mixture was quenched with water and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered through paper, and concentrated under vacuum.

[1605] The above residue was dissolved in DCM (220 mL), DCC (9.03 g, 43.79 mmol) and DMAP (9.73 g, 79.61 mmol) were added at 0 °C. The resulting solution was stirred at 25 °C for 16 h. The reaction mixture was concentrated under vacuum. The residue was purified by silica gel column chromatography, eluted with 0 - 45% EtOAc in petroleum ether to afford tert-butyl ((5R*,6R*)-6-((R)-3-((tert-butyldimethylsilyl)oxy)-2-methoxypropyl)-8-oxo-2- (trifluoromethyl)-5,8-dihydro-6H-pyrano[3,4-b]pyridin-5-yl)carbamate (3.40 g, 15%) as a white solid. MS ESI calculated for C24H37F3N2OeSi [M+H]⁺, 535.24; found, 535.25.

[1606] To a stirred solution of tert-butyl ((5R*,6R*)-6-((R)-3-((tert- butyldimethylsilyl)oxy)-2-methoxypropyl)-8-oxo-2-(trifluoromethyl)-5,8-dihydro-6H- pyrano[3,4-b]pyridin-5-yl)carbamate (3.40 g, 6.36 mmol) in THF (36 mL) and EtOH (9 mL) were added CaCh (847 mg, 7.63 mmol) and NaBFL (722 mg, 19.07 mmol) at 0 °C. The resulting solution was stirred at 25 °C for 4 h. The reaction mixture was quenched by the addition of water at 0 °C and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered through paper. The filtrate was concentrated under vacuum. The residue was purified by silica gel column chromatography, eluted with 0 - 50% EtOAc in petroleum ether to afford tert-butyl ((lR*,2R*,4R)-5-((tert-butyldimethylsilyl)oxy)-2-hydroxy-l-(2-(hydroxymethyl)-6- (trifhioromethyl)pyridin-3-yl)-4-methoxypentyl)carbamate (1.0 g, 29%) as a white solid. MS ESI calculated for C24H₄iF₃N2O₆Si [M+H]⁺, 539.27; found, 539.30.

Step-4:

[1607] To a stirred solution of tert-butyl ((lR*,2R*,4R)-5-((tert-butyldimethylsilyl)oxy)-2- hydroxy-l-(2-(hydroxymethyl)-6-(trifluoromethyl)pyridin-3-yl)-4-methoxypentyl)carbamate (600 mg, 1.11 mmol) in toluene (6 mL) was added 2-(tributyl-X⁵- phosphaneylidene)acetonitrile (CAS No. 157141-27-0) (538 mg, 2.23 mmol) at 25 °C. The resulting solution was stirred at 110 °C for 16 h. The solvents were removed under vacuum. The residue was purified by silica gel column chromatography, eluted with 0 ~ 35% EtOAc in petroleum ether to afford tert-butyl ((5R*,6R*)-6-((R)-3-((tert-butyldimethylsilyl)oxy)-2- methoxypropyl)-2-(trifluoromethyl)-5,8-dihydro-6H-pyrano[3,4-b]pyridin-5-yl)carbamate (210 mg, 36%) as a white solid. MS ESI calculated for Ci^gFs zOsSi [M+H]⁺, 521.26; found, 521.30.

Step-5:

[1608] To a stirred solution of tert-butyl ((5R*,6R*)-6-((R)-3-((tert- butyldimethylsilyl)oxy)-2-methoxypropyl)-2-(trifluoromethyl)-5,8-dihydro-6H-pyrano[3,4- b]pyridin-5-yl)carbamate (210 mg, 0.40 mmol) in THF (3 mL) was added TBAF (210 mg, 0.80 mmol) at 25 °C. The resulting solution was stirred at 25 °C for 2 h. The reaction mixture was quenched with water and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered through paper. The filtrate was concentrated under vacuum. The residue was purified by silica gel column chromatography, eluted with 0 ~ 50% EtOAc in petroleum ether to afford tert-butyl ((5R*,6R*)-6-((R)-3-hydroxy-2-methoxypropyl)-2-(trifluoromethyl)-5,8-dihydro-6H- pyrano[3,4-b]pyridin-5-yl)carbamate (110 mg, 67%) as a colorless oil. MS ESI calculated for C18H25F3N2O5 [M+H]⁺, 407.17; found, 407.15.

Step-6:

[1609] To a stirred solution of tert-butyl ((5R*,6R*)-6-((R)-3-hydroxy-2-methoxypropyl)- 2-(trifhioromethyl)-5,8-dihydro-6H-pyrano[3,4-b]pyridin-5-yl)carbamate (210 mg, 0.51 mmol) in toluene (3 mL) was added 2-(tributyl ⁵-phosphaneylidene)acetonitrile (CAS No. 157141-27-0) (249 mg, 1.03 mmol) at 25 °C. The resulting solution was stirred at 110 °C for 16 h. The solvents were removed under vacuum. The residue was purified by silica gel column chromatography, eluted with 0 ~ 50% EtOAc in petroleum ether to afford tert-butyl (3R,4aR*,10bR*)-3-methoxy-8-(trifluoromethyl)-2,3,4,4a,6,10b-hexahydro-lH-pyrano[3,2- b:5,4-b']dipyridine-l-carboxylate (100 mg, 49%) as a yellow oil. MS ESI calculated for C18H23F3N2O4 [M+H]⁺, 389.16; found, 389.25.

Step-7:

A97

[1610] A mixture of tert-butyl (3R,4aR*,10bR*)-3-methoxy-8-(trifluoromethyl)- 2,3,4,4a,6,10b-hexahydro-lH-pyrano[3,2-b:5,4-b']dipyridine-l-carboxylate (100 mg, 0.26 mmol) and hydrogen chloride (4.0 M in ethyl acetate) (2 mL) was stirred at 25 °C for 1 h. The solvents were removed under vacuum to afford (3R,4aR*,10bR*)-3-methoxy-8- (trifluoromethyl)-2,3,4,4a,6, 1 Ob-hexahydro- 1 H-pyrano [3 ,2-b :5 ,4-b'] dipyridine hydrochloride (A97) (100 mg, crude) as a yellow solid. MS ESI calculated for C13H15F3N2O2 [M+H]⁺, 289.11; found, 289.05. 'H NMR (400 MHz, DMSO) 8 10.75 (br, 1H), 8.87 (s, 1H), 8.57 - 8.54 (m, 1H), 7.95 (d, J= 8.0 Hz, 1H), 5.04 - 4.66 (m, 2H), 4.57 - 4.56 (m, 1H), 4.21 - 4.12 (m, 1H), 3.70 - 3.69 (m, 1H), 3.37 - 3.35 (m, 5H), 2.43 - 2.33 (m, 1H), 2.11 - 2.00 (m, 1H). Absolute stereochemistry was not determined.

Intermediate A98 isomer 1: rel-(4R,4aS,10bR)-4-methoxy-8-(trifluoromethyl)-

2,3,4,4a,6,10b-hexahydro-lH-pyrano[3,2-b:5,4-b']dipyridine isomer 1

A98 isomer 1

Intermediate A98 isomer 2: rel-(4R,4aR,10bS)-4-methoxy-8-(trifluoromethyl)- 2,3,4,4a,6,10b-hexahydro-lH-pyrano[3,2-b:5,4-b']dipyridine isomer 2

[1611] To a stirred solution of ethyl 3-bromo-6-(trifluoromethyl)picolinate (30 g, 100.65 mmol) and 1:1 mixture of (R,E)-tert-butyl((3-methoxy-5-(4,4,5,5-tetramethyl-l,3,2- dioxaborolan-2-yl)pent-4-en-l-yl)oxy)diphenylsilane and (S,E)-tert-butyl((3-methoxy-5- (4,4,5,5-tetramethyl-l,3,2-dioxaborolan-2-yl)pent-4-en-l-yl)oxy)diphenylsilane (58.04 g, 120.78 mmol) in dioxane (300 mL/ELO (30 mL) were added AcOK (29.63 g, 301.95 mmol) and Pd(dppf)Ch (8.22 g, 10.06 mmol) at room temperature. The resulting mixture was stirred at 100 °C for 16 h. The reaction was quenched by water and extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SO4. After filtration, the filtrate was concentrated under reduced pressure. The resulting residue was purified by Combi Flash using a 330 g silica gel column eluted with 0-10% ethyl acetate in petroleum ether to afford a 1:1 mixture of ethyl (R,E)-3-(5-((tert-butyldiphenylsilyl)oxy)-3- methoxypent-l-en-l-yl)-6-(trifluoromethyl)picolinate and ethyl (S,E)-3-(5-((tert- butyldiphenylsilyl)oxy)-3-methoxypent-l-en-l-yl)-6-(trifluoromethyl)picolinate (50 g, 86%) as a yellow oil. MS ESI calculated for CsiHaeFsNCESi [M+H]⁺, 572.24; found, 572.15.

Step-2:

[1612] To a stirred solution of tert-butyl carbamate (32.56 g, 277.93 mmol) in propan-l-ol (330 mL) was added a solution of NaOH (9.68 g, 242.01 mmol) in H2O (290 mL) at room temperature under nitrogen atmosphere. The resulting mixture was stirred at room temperature for 10 minutes, l,3-dichloro-5,5-dimethylimidazolidine-2, 4-dione (26.50 g, 134.48 mmol) was added at room temperature. After stirring at room temperature for additional 30 minutes, (DHQ)2PHAL (supplier: Shanghai Accela ChemBio Co., Ltd. CAS# 140924-50-1) (6.98 g, 8.96 mmol) and 1:1 mixture of ethyl (R,E)-3-(5-((tert- butyldiphenylsilyl)oxy)-3-methoxypent-l-en-l-yl)-6-(trifluoromethyl)picolinate and ethyl (S,E)-3-(5-((tert-butyldiphenylsilyl)oxy)-3-methoxypent- 1 -en- 1 -yl)-6- (trifluoromethyl)picolinate (50 g, 89.65 mmol) were added to the mixture at 0 °C, this was followed by the addition of Potassium osmate(VI) dihydrate (3.3 g, 8.96 mmol). The resulting mixture was stirred at room temperature for additional 16 h. The resulting mixture was extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SO4. After filtration, the filtrate was concentrated under reduced pressure. [1613] The above residue was dissolved in DCM (500 mL), this was followed by the addition of DCC (32.86 g, 159.27 mmol) and DMAP (1.77 g, 14.48 mmol) at room temperature. The resulting mixture was concentrated under reduced pressure. The resulting residue was purified by Combi Flash using a 330 g silica gel column eluted with 0-30% ethyl acetate in petroleum ether to afford a 1:1 mixture of tert-butyl ((5R*,6S*)-6-((R)-3-((tert- butyldiphenylsilyl)oxy)-l-methoxypropyl)-8-oxo-2-(trifluoromethyl)-5,8-dihydro-6H- pyrano[3,4-b]pyridin-5-yl)carbamate and tert-butyl ((5R*,6S*)-6-((S)-3-((tert- butyldiphenylsilyl)oxy)-l-methoxypropyl)-8-oxo-2-(trifluoromethyl)-5,8-dihydro-6H- pyrano[3,4-b]pyridin-5-yl)carbamate (52 g, 54%) as a yellow solid. MS ESI calculated for C₃4H₄iF₃N2O₆Si [M+H]⁺, 659.27; found, 659.15.

Step-3:

[1614] To a stirred solution of 1 : 1 mixture of tert-butyl ((5R*,6S*)-6-((R)-3-((tert- butyldiphenylsilyl)oxy)-l-methoxypropyl)-8-oxo-2-(trifluoromethyl)-5,8-dihydro-6H- pyrano[3,4-b]pyridin-5-yl)carbamate and tert-butyl ((5R*,6S*)-6-((S)-3-((tert- butyldiphenylsilyl)oxy)-l-methoxypropyl)-8-oxo-2-(trifluoromethyl)-5,8-dihydro-6H- pyrano[3,4-b]pyridin-5-yl)carbamate (52 g, 78.93 mmol) in THF (500 mL) was added NaBH4 (2.99 g, 78.93 mmol) at 0 °C under nitrogen atmosphere. The resulting mixture was stirred at room temperature for 16 h. The reaction was quenched with ice water and extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous NaaSC After filtration, the filtrate was concentrated under reduced pressure to afford a 1: 1 mixture of tert-butyl ((lR*,2S*,3R)-5-((tert-butyldiphenylsilyl)oxy)-2-hydroxy-l-(2-(hydroxymethyl)-6- (trifhioromethyl)pyridin-3-yl)-3-methoxypentyl)carbamate and tert-butyl ((lR*,2S*,3S)-5- ((tert-butyldiphenylsilyl)oxy)-2-hydroxy-l-(2-(hydroxymethyl)-6-(trifluoromethyl)pyridin-3- yl)-3-methoxypentyl)carbamate (50 g, crude) as a brown oil. MS ESI calculated for C34H₄5F₃N2O6Si [M+H]⁺, 663.30; found, 663.35.

[1615] To a stirred solution of 1 : 1 mixture of tert-butyl ((lR*,2S*,3R)-5-((tert- butyldiphenylsilyl)oxy)-2-hydroxy-l-(2-(hydroxymethyl)-6-(trifluoromethyl)pyridin-3-yl)-3- methoxypentyl)carbamate and tert-butyl ((lR*,2S*,3S)-5-((tert-butyldiphenylsilyl)oxy)-2- hydroxy-l-(2-(hydroxymethyl)-6-(trifluoromethyl)pyridin-3-yl)-3-methoxypentyl)carbamate (50 g, 75.43 mmol) in toluene (500 mL) was added 2-(tributyl- ⁵- phosphaneylidene)acetonitrile (CAS No. 157141-27-0) (36.41 g, 150.87 mmol) at room temperature under nitrogen atmosphere. The resulting mixture was stirred at 110 °C for 16 h. The resulting mixture was concentrated under vacuum. The residue was purified by silica gel column chromatography, eluted with 0-30% ethyl acetate in petroleum ether to afford a 2:1 mixture of rel-tert-butyl ((5R,6S)-6-((S)-3-((tert-butyldiphenylsilyl)oxy)-l-methoxypropyl)- 2-(trifhioromethyl)-5,8-dihydro-6H-pyrano[3,4-b]pyridin-5-yl)carbamate isomer 1 and rel- tert-butyl ((5R,6S)-6-((S)-3-((tert-butyldiphenylsilyl)oxy)-l-methoxypropyl)-2- (trifhioromethyl)-5,8-dihydro-6H-pyrano[3,4-b]pyridin-5-yl)carbamate isomer 2 (5.2 g, 10%) as a yellow oil. MS ESI calculated for C34H43F3N2OsSi [M+H]⁺, 645.29; found, 645.30.

[1616] To a stirred solution of 2: 1 mixture of rel-tert-butyl ((5R,6S)-6-((S)-3-((tert- butyldiphenylsilyl)oxy)-l-methoxypropyl)-2-(trifluoromethyl)-5,8-dihydro-6H-pyrano[3,4- b]pyridin-5-yl)carbamate isomer 1 and rel-tert-butyl ((5R,6S)-6-((S)-3-((tert- butyldiphenylsilyl)oxy)-l-methoxypropyl)-2-(trifluoromethyl)-5,8-dihydro-6H-pyrano[3,4- b]pyridin-5-yl)carbamate isomer 2 (5.2 g, 8.06 mmol) in THF (50 mL) was added TBAF (2.53 g, 9.67 mmol) at room temperature. The resulting mixture was stirred at room temperature for 2 h. The resulting mixture was concentrated under reduced pressure. The resulting residue was purified by Combi Flash using a 120 g silica gel column eluted with 0- 80% ethyl acetate in petroleum ether to afford a 2: 1 mixture of rel-tert-butyl ((5R,6S)-6-((S)- 3-hydroxy-l-methoxypropyl)-2-(trifluoromethyl)-5,8-dihydro-6H-pyrano[3,4-b]pyridin-5- yl)carbamate isomer 1 and rel-tert-butyl ((5R,6S)-6-((R)-3-hydroxy-l-methoxypropyl)-2- (trifhioromethyl)-5,8-dihydro-6H-pyrano[3,4-b]pyridin-5-yl)carbamate isomer 2 (2.3 g, 70%) as a yellow oil. MS ESI calculated for C18H25F3N2O5 [M+H]⁺, 407.17; found, 407.20.

Step-6:

[1617] To a stirred solution of 2: 1 mixture of rel-tert-butyl ((5R,6S)-6-((S)-3-hydroxy-l- methoxypropyl)-2-(trifluoromethyl)-5,8-dihydro-6H-pyrano[3,4-b]pyridin-5-yl)carbamate isomer 1 and rel-tert-butyl ((5R,6S)-6-((R)-3-hydroxy-l-methoxypropyl)-2-(trifluoromethyl)- 5,8-dihydro-6H-pyrano[3,4-b]pyridin-5-yl)carbamate isomer 2 (2.2 g, 5.41 mmol) in toluene (22 mL) was added 2-(tributyl- ⁵-phosphaneylidene)acetonitrile (CAS No. 157141-27-0) (2.61 g, 10.81 mmol) at room temperature. The resulting mixture was stirred at 110 °C for 16 h. The resulting mixture was concentrated under reduced pressure. The resulting residue was purified by Combi Flash using a 80 g silica gel column eluted with 0-20% ethyl acetate in petroleum ether to afford a 2:1 mixture of rel-tert-butyl (4R,4aS,10bR)-4-methoxy-8- (trifhioromethyl)-2,3,4,4a,6, 1 Ob-hexahydro- 1 H-pyrano [3 ,2-b :5 ,4-b'] dipyridine- 1 -carboxylate isomer 1 and rel-tert-butyl (4R,4aR,10bS)-4-methoxy-8-(trifhioromethyl)-2,3,4,4a,6,10b- hexahydro-lH-pyrano[3,2-b:5,4-b']dipyridine-l -carboxylate isomer 2 (1.3 g, 61%) as a yellow oil. [1618] The above mixture was separated by Prep-HPLC with the following conditions [Column: Xselect CSH OBD Column 30*150mm, 5pm; Mobile Phase A: Water(0.1% FA), Mobile Phase B: ACN; Flow rate: 60 mL/min; Gradient (B%): 44% B to 66% B in 8min; Wave Length: 254/220 nm; RTl(min): 6; RT2(min): 6.5] to afford rel-tert-butyl (4R,4aS,10bR)-4-methoxy-8-(trifluoromethyl)-2,3,4,4a,6,10b-hexahydro-lH-pyrano[3,2- b:5,4-b']dipyridine-l-carboxylate isomer 1 (558 mg, 42%) as a yellow solid as the second eluting peak. MS ESI calculated for C18H23F3N2O4 [M+H]+, 389.16; found, 389.20. Relative stereochemistry was determined by NOESY.

[1619] The purification also affords rel-tert-butyl (4R,4aR,10bS)-4-methoxy-8- (trifluoromethyl)-2,3,4,4a,6, 1 Ob-hexahydro- 1 H-pyrano [3 ,2-b :5 ,4-b'] dipyridine- 1 -carboxylate isomer 2 (130 mg, 10%) as a yellow solid as the first eluting peak. MS ESI calculated for C18H23F3N2O4 [M+H]+, 389.16; found, 389.20. Relative stereochemistry was determined by NOESY.

Step-7: 1

[1620] A mixture of rel-tert-butyl (4R,4aS, 10bR)-4-methoxy-8-(trifhioromethyl)- 2,3,4,4a,6,10b-hexahydro-lH-pyrano[3,2-b:5,4-b']dipyridine-l-carboxylate isomer 1 (558 mg, 1.43 mmol) and HC1 (4.0 M in 1,4-dioxane) (10 mL) was stirred at room temperature for 1 h. The resulting mixture was concentrated under vacuum to afford rel-(4R,4aS,10bR)-4- methoxy-8-(trifluoromethyl)-2,3,4,4a,6,10b-hexahydro-lH-pyrano[3,2-b:5,4-b']dipyridine hydrochloride isomer 1 (510 mg, crude)(A98 isomer 1) as a yellow solid. MS ESI calculated for C13H15F3N2O2 [M+H]⁺, 289.11; found, 289.05. 'H NMR (400 MHz, DMSO) 5 10.90 (s, 1H), 8.97 (s, 1H), 8.46 (d, J = 8.0 Hz, 1H), 7.96 (d, J = 8.0 Hz, 1H), 4.93 - 4.88 (m, 2H), 4.58 (s, 1H), 4.36 (t, J = 2.0 Hz, 1H), 3.73 - 3.62 (m, 1H), 3.57 (s, 3H), 3.32 - 3.20 (m, 1H), 3.12 - 3.10 (m, 1H), 1.97 - 1.83 (m, 2H). Absolute stereochemistry was not determined.

Step-8: Isomer 2

[1621] A mixture of rel-tert-butyl (4R,4aR,10bS)-4-methoxy-8-(trifluoromethyl)- 2,3,4,4a,6,10b-hexahydro-lH-pyrano[3,2-b:5,4-b']dipyridine-l-carboxylate isomer 2 (130 mg, 0.33 mmol) and HC1 (4.0 M in 1,4-dioxane) (3 mL) was stirred at room temperature for 1 h. The resulting mixture was concentrated under vacuum to afford rel-(4R,4aR,10bS)-4- methoxy-8-(trifluoromethyl)-2,3,4,4a,6,10b-hexahydro-lH-pyrano[3,2-b:5,4-b']dipyridine hydrochloride isomer 2 (90 mg, crude)(A98 isomer 2) as a yellow solid. MS ESI calculated for C13H15F3N2O2 [M+H]⁺, 289.11; found, 289.05. ¹H NMR (300 MHz, DMSO) 5 10.74 (s, 1H), 9.10 (s, 1H), 8.58 - 8.47 (m, 1H), 7.97 (d, J = 8.1 Hz, 1H), 4.97 (s, 2H), 4.52 - 4.50 (m, 1H), 4.23 - 4.21 (m, 1H), 3.71 - 3.70 (m, 1H), 3.40 (s, 3H), 3.10 - 3.09 (m, 2H), 2.01 - 1.94 (m, 2H). Absolute stereochemistry was not determined.

Intermediate A99 isomer 1: (3R,4aS,9bS)-7-(difluoromethoxy)-3-methyl-l,2,3,4,4a,9b- hexahydrofuro[2,3-b:4,5-b']dipyridine, isomer 1 isomer 1

Intermediate A99 isomer 2: (3S,4aS,9bS)-7-(difluoromethoxy)-3-methyl-l,2,3,4,4a,9b- hexahydrofuro[2,3-b:4,5-b']dipyridine, isomer 2 isomer 2

Step-1:

[1622] To a stirred mixture of 5-bromo-6-chloropyridin-2-amine (20.0 g, 96.40 mmol) in H2SO4 (450 mL) was added a solution of NaNCh (18.62 g, 269.93 mmol) in H2O (200 mL) dropwise at 0 °C under nitrogen atmosphere. The resulting mixture was stirred at 0 °C for 1 h under nitrogen atmosphere. The resulting mixture was extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SO4. After filtration, the filtrate was concentrated under reduced pressure to afford 5-bromo-6-chloropyridin-2-ol (23 g, crude) as a brown solid. MS ESI calculated for CsELBrClNO [M+H]⁺, 207.91; found, 207.95.

Step-2:

[1623] A mixture of 5-bromo-6-chloropyridin-2-ol (20.0 g, 95.95 mmol), sodium 2-chloro- 2,2-difluoroacetate (29.26 g, 191.90 mmol) and K2CO3 (15.91 g, 115.14 mmol) in DMF (400 mL) was stirred at 100 °C for 2 h. The mixture was allowed to cool down to room temperature and quenched with water. The resulting mixture was extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SO4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-10% ethyl acetate in petroleum ether to afford 3-bromo-2-chloro-6-(difhioromethoxy)pyridine (18.1 g, 72% over 2 steps) as a colorless oil. MS ESI calculated for CeHsBrCIE^NO [M+H]⁺, 257.91; found, 257.80.

Step-3:

[1624] To a stirred solution of 3-bromo-2-chloro-6-(difluoromethoxy)pyridine (2.0 g, 7.73 mmol) and 1:1 mixture of tert-butyl (R)-3-methyl-5-oxopiperidine-l-carboxylate and tertbutyl (S)-3-methyl-5-oxopiperidine-l-carboxylate (2.48 g, 11.60 mmol) in toluene (40 mL) were added K3PO4 (3.29 g, 15.47 mmol) and P(t-Bu)s Pd G3 (395 mg, 0.77 mmol) at room temperature. The resulting mixture was stirred at 60 °C for 16 h under nitrogen atmosphere. The mixture was allowed to cool down to room temperature and concentrated under vacuum. The residue was purified by silica gel column chromatography, eluted with 0-50% ethyl acetate in petroleum ether to afford a 1:1:1: 1 mixture of tert-butyl (2S,5R)-2-(2-chloro-6- (difluoromethoxy)pyridin-3-yl)-5-methyl-3-oxopiperi dine- 1 -carboxylate and tert-butyl (2S,5S)-2-(2-chloro-6-(difluoromethoxy)pyridin-3-yl)-5-methyl-3-oxopiperidine-l- carboxylate and tert-butyl (2R,5R)-2-(2-chloro-6-(difluoromethoxy)pyridin-3-yl)-5-methyl-3- oxopiperidine-1 -carboxylate and tert-butyl (2R,5S)-2-(2-chloro-6-(difluoromethoxy)pyridin- 3-yl)-5-methyl-3-oxopiperidine-l -carboxylate (1.81 g, 59%) as a brown oil. MS ESI calculated for C17H21CIF2N2O4 [M+H]⁺, 391.12; found, 391.10.

Step-4:

[1625] To a stirred solution of 1 : 1 : 1 : 1 mixture of tert-butyl (2S,5R)-2-(2-chloro-6- (difluoromethoxy)pyridin-3-yl)-5-methyl-3-oxopiperidine- 1 -carboxylate and tert-butyl (2S,5S)-2-(2-chloro-6-(difluoromethoxy)pyridin-3-yl)-5-methyl-3-oxopiperidine-l- carboxylate and tert-butyl (2R,5R)-2-(2-chloro-6-(difluoromethoxy)pyridin-3-yl)-5-methyl-3- oxopiperidine-1 -carboxylate and tert-butyl (2R,5S)-2-(2-chloro-6-(difluoromethoxy)pyridin- 3-yl)-5-methyl-3-oxopiperidine-l-carboxylate (1.8 g, 4.60 mmol) in ACN (20 mL) were added DABCO (5.07 g, 23.03 mmol), HCOOH (635 mg, 13.81 mmol) and RuCl[(S,S- TsDPEN)](p-cymene) (146 mg, 0.23 mmol) at 0 °C. The resulting mixture was stirred at room temperature for 16 h. The resulting mixture was quenched with water and extracted with EtOAc. The organic layer was dried over anhydrous Na2SC>4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-70% ethyl acetate in petroleum ether to afford a 1:1 mixture of tert-butyl (2S,3S,5R)-2-(2-chloro-6-(difluoromethoxy)pyridin-3-yl)-3-hydroxy-5- methylpiperidine-1 -carboxylate and tert-butyl (2S,3S,5S)-2-(2-chloro-6- (difluoromethoxy)pyridin-3-yl)-3-hydroxy-5-methylpiperidine-l-carboxylate (1.02 g, 56%) as a yellow oil. MS ESI calculated for C17H23CIF2N2O4 [M+H]⁺, 393.13; found, 393.10.

Step-5:

[1626] A solution of a 1:1 mixture of tert-butyl (2S,3S,5R)-2-(2-chloro-6- (difluoromethoxy)pyridin-3-yl)-3-hydroxy-5-methylpiperidine-l-carboxylate and tert-butyl (2S,3S,5S)-2-(2-chloro-6-(difluoromethoxy)pyridin-3-yl)-3-hydroxy-5-methylpiperidine-l- carboxylate (1.0 g, 2.54 mmol) and t-BuOK (428 mg, 3.81 mmol) in THF (20 mL) was stirred at 70 °C for 2 h under nitrogen atmosphere. The mixture was allowed to cool down to room temperature and concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0^10% ethyl acetate in petroleum ether to afford a 1:1 mixture of tert-butyl (3R,4aS,9bS)-7-(difluoromethoxy)-3-methyl-3,4,4a,9b- tetrahydrofuro[2,3-b:4,5-b']dipyridine-l(2H)-carboxylate and tert-butyl (3S,4aS,9bS)-7- (difluoromethoxy)-3-methyl-3,4,4a,9b-tetrahydrofuro[2,3-b:4,5-b']dipyridine-l(2H)- carboxylate (586 mg, 64%) as a white solid.

[1627] The 1 :1 mixture of tert-butyl (3R,4aS,9bS)-7-(difluoromethoxy)-3-methyl- 3,4,4a,9b-tetrahydrofuro[2,3-b:4,5-b']dipyridine-l(2H)-carboxylate and tert-butyl (3S,4aS,9bS)-7-(difluoromethoxy)-3-methyl-3,4,4a,9b-tetrahydrofuro[2,3-b:4,5- b']dipyridine-l(2H)-carboxylate (580 mg) was separated by prep-chiral HPLC with the following conditions [Column: CHIRALPAK IF, 2*25 cm, 5 pm; Mobile Phase A: Hex(0.5% 2M NH₃-MeOH)— HPLC, Mobile Phase B: MeOH: DCM=1: 1-HPLC; Flow rate: 20 mL/min; Gradient (B%): isocratic 10% B to 10% in lOmin; Wave Length: 220/254 nm; RTl(min): 5.56; RT2(min): 7.35; Sample Solvent: MeOH: DCM=1: 1-HPLC] to afford tertbutyl (3R,4aS,9bS)-7-(difhioromethoxy)-3-methyl-3,4,4a,9b-tetrahydrofuro[2,3-b:4,5- b']dipyridine-l(2H)-carboxylate, isomer 1 (230 mg, 39%) as a white solid as the first peak on chiral HPLC. MS ESI calculated for C17H22F2N2O4 [M+H]⁺, 357.15; found, 357.15.

[1628] The separation also afford tert-butyl (3S,4aS,9bS)-7-(difluoromethoxy)-3-methyl- 3,4,4a,9b-tetrahydrofuro[2,3-b:4,5-b']dipyridine-l(2H)-carboxylate, isomer 2 (220 mg, 38%) as a colorless oil as the second peak on chiral HPLC. MS ESI calculated for C17H22F2N2O4 [M+H]⁺, 357.15; found, 357.15.

Step-6:

A99 isomer 1

[1629] To a mixture of tert-butyl (3R,4aS,9bS)-7-(difluoromethoxy)-3-methyl-3,4,4a,9b- tetrahydrofuro[2,3-b:4,5-b']dipyridine-l(2H)-carboxylate (230 mg, 0.64 mmol) in ethyl acetate (2 mL) was added HC1 (4.0 M in 1,4-dioxane) (2 mL). The mixture was stirred at room temperature for 16 h. The resulting mixture was concentrated under vacuum to afford (3R,4aS,9bS)-7-(difluoromethoxy)-3-methyl-l,2,3,4,4a,9b-hexahydrofuro[2,3-b:4,5- b']dipyridine, hydrochloride (A99, isomer 1) (220 mg, crude) as a white solid. MS ESI calculated for C12H14F2N2O2 [M+H]⁺, 257.10; found, 257.10. ¹H NMR (400 MHz, DMSO- d₆) 5 10.29 (s, 1H), 9.21 (s, 1H), 8.12 (d, J = 8.0 Hz, 1H), 7.65 (t, J = 72.4 Hz, 1H), 6.73 (d, J = 8.0 Hz, 1H), 5.18 - 4.92 (m, 2H), 3.26 - 3.17 (m, 1H), 2.68 - 2.58 (m, 1H), 2.36 - 2.20 (m, 1H), 2.07 - 2.00 (m, 1H), 1.74 - 1.63 (m, 1H), 1.02 (d, J= 6.8 Hz, 3H).

Step-7:

A99 isomer 2

[1630] To a solution of teit-butyl (3S,4aS,9bS)-7-(difluoromethoxy)-3-methyl-3,4,4a,9b- tetrahydrofuro[2,3-b:4,5-b']dipyridine-l(2H)-carboxylate isomer 2 (220 mg, 0.61 mmol) in ethyl acetate (2 mL) was added HC1 (4.0 M in 1,4-dioxane) (2 mL). The mixture was stirred at room temperature for 16 h. The resulting mixture was concentrated under vacuum to afford (3S,4aS,9bS)-7-(difhioromethoxy)-3-methyl-l,2,3,4,4a,9b-hexahydrofuro[2,3-b:4,5- b']dipyridine, hydrochloride (A99, isomer 2) (145 mg, crude) as a white solid. MS ESI calculated for C12H14F2N2O2 [M+H]⁺, 257.10; found, 257.10. 'H NMR (400 MHz, DMSO- d₆) 5 10.58 (s, 1H), 8.69 (s, 1H), 8.06 (d, J = 8.0 Hz, 1H), 7.65 (t, J = 72.4 Hz, 1H), 6.74 ( d, J = 8.0 Hz, 1H), 5.01 - 4.72 (m, 2H), 3.10 - 2.91 (m, 1H), 2.68 - 2.56 (m, 1H), 2.36 - 2.24 (m, 1H), 2.04 - 1.90 (m, 1H), 1.77 - 1.66 (m, 1H), 0.98 (d, J = 6.8 Hz, 3H).

Intermediate A100: rel-(4aR,10bR)-2,3,4,4a,6,10b-hexahydro-lH-pyrano[3,2-b:5,4- b']dipyridine-8-carbonitrile

[1631] To a stirred solution of rel-(4aR,10bR)-8-chloro-2,3,4,4a,6,10b-hexahydro-lH- pyrano[3,2-b:5,4-b']dipyridine (500 mg, 2.22 mmol), Zn(CN)2 (496 mg, 4.22 mmol) and XPhos (106 mg, 0.22 mmol) in DMF (10 mL) were added XPhos Pd G3 (188 mg, 0.22 mmol) and Zinc (581 mg, 8.90 mmol) at room temperature under nitrogen atmosphere. The resulting mixture was stirred at 130 °C for overnight under nitrogen atmosphere. The mixture was allowed to cool down to room temperature. The mixture was quenched with water and extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous NaaSCU After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by reversed-phase flash column chromatography with 5%~95%MeCN in Water (10 mmol/L NH4HCO3) to afford rel-(4aR,10bR)-2,3,4,4a,6,10b-hexahydro-lH- pyranofS^-biS^-b'Jdipyridine-S-carbonitrile (A100) (110 mg, 22% yield) as a colorless semi-solid. MS ESI calculated for C12H13N3O [M+H]⁺, 216.11; found, 216.10. 'H NMR (400 MHz, DMSO-J₆) 5 7.96 (d, J = 7.8 Hz, 1H), 7.90 (d, J = 7.8 Hz, 1H), 4.94 - 4.55 (m, 2H),

3.73 - 3.62 (m, 2H), 2.97 - 2.80 (m, 1H), 2.67 - 2.63 (m, 1H), 2.04 - 1.87 (m, 1H), 1.79 -

1.74 (m, 1H), 1.59 - 1.54 (m, 1H), 1.37 - 1.31 (m, 1H).

Intermediate A101: 7:2 mixture of rel-(3R,4aS,9bS)-6-fluoro-7-methoxy-3-methyl- l,2,3,4,4a,9b-hexahydrobenzofuro[3,2-b]pyridine isomer 1 and rel-(3R,4aS,9bS)-6-fhioro-7- methoxy-3-methyl-l,2,3,4,4a,9b-hexahydrobenzofuro[3,2-b]pyridine isomer 2

[1632] To a stirred solution of l-bromo-2,3-difluoro-4-methoxybenzene (3 g, 13.452 mmol) and tert-butyl 3-methyl-5-oxopiperidine-l -carboxylate (2.87 g, 13.452 mmol) in Toluene (60 mL) were added K3PO4 (6.85 g, 32.285 mmol) and P(t-Bu)s Pd G3 (0.48 g, 0.942 mmol) at room temperature under nitrogen atmosphere. The resulting mixture was stirred at 60°C for 16h. The resulting mixture was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with PE / EtOAc (2:1) to afford a 1 :1 : 1 : 1 mixture of tert-butyl (2S,5R)-2-(2,3-difluoro-4-methoxyphenyl)-5-methyl-3- oxopiperidine-1 -carboxylate and tert-butyl (2R,5S)-2-(2,3-difluoro-4-methoxyphenyl)-5- methyl-3-oxopiperidine-l-carboxylate and tert-butyl (2R,5R)-2-(2,3-difhioro-4- methoxyphenyl)-5-methyl-3-oxopiperidine-l-carboxylate and tert-butyl (2S,5S)-2-(2,3- difluoro-4-methoxyphenyl)-5-methyl-3-oxopiperidine-l-carboxylate (1.3 g, 27.19%yield, 85%purity) as a yellow oil. MS ESI calculated for C18H23F2NO4 [M+H]⁺, 356.16; found, 356.05.

Step 2: [1633] To a stirred solution of 1 : 1 : 1 : 1 mixture of tert-butyl (2S,5R)-2-(2,3-difluoro-4- methoxyphenyl)-5-methyl-3-oxopiperidine-l-carboxylate and tert-butyl (2R,5S)-2-(2,3- difluoro-4-methoxyphenyl)-5-methyl-3-oxopiperidine-l-carboxylate and tert-butyl (2R,5R)- 2-(2,3-difhioro-4-methoxyphenyl)-5-methyl-3-oxopiperidine- 1-carboxylate and tert-butyl (2S,5S)-2-(2,3-difluoro-4-methoxyphenyl)-5-methyl-3-oxopiperidine- 1 -carboxylate (1.3 g, 3.658 mmol,) and DABCO (4.43 g, 20.119 mmol) in MeCN (20 mL) were added RuCl[(S,S- TsDPEN)](p-cymene) (0.06 g, 0.091 mmol) and HCOOH (0.51 g, 10.974 mmol) at 0°C under nitrogen atmosphere. The resulting mixture was stirred at room temperature for 16 h. The mixture was basified with saturated NaHCCL (aq.) to pH 8 and extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SO4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with PE / EtOAc (1:1) to afford a 7:2 mixture of rel-tert-butyl (2R,3R,5S)-2-(2,3-difhioro-4-methoxyphenyl)-3-hydroxy-5-methylpiperidine- 1 - carboxylate isomer 1 and rel-tert-butyl (2R,3R,5S)-2-(2,3-difluoro-4-methoxyphenyl)-3- hydroxy-5-methylpiperidine- 1-carboxylate isomer 2 (700 mg, 53%) as a yellow oil. MS ESI calculated for C18H25F2NO4 [M+H]⁺, 358.18; found, 358.20. isomer 1 isomer 2 isomer 1 isomer 2

[1634] A solution of 7:2 mixture of rel-tert-butyl (2R,3R,5S)-2-(2,3-difluoro-4- methoxyphenyl)-3-hydroxy-5-methylpiperidine- 1-carboxylate isomer 1 and rel-tert-butyl (2R,3R,5S)-2-(2,3-difluoro-4-methoxyphenyl)-3-hydroxy-5-methylpiperidine-l-carboxylate isomer 2 (700 mg, 1.959 mmol) and t-BuOK (439 mg, 3.91 mmol) in THF (6 mL) was stirred at 70 °C overnight under nitrogen atmosphere. The resulting mixture was concentrated under vacuum. The residue was purified by silica gel column chromatography, eluted with PE / EtOAc (5:1) to afford a 7:2 mixture of rel-tert-butyl (3R,4aS,9bS)-6-fluoro-7-methoxy-3- methyl-3,4,4a,9b-tetrahydrobenzofuro[3,2-b]pyridine-l(2H)-carboxylate isomer 1 and rel- tert-butyl (3R,4aS,9bS)-6-fhioro-7-methoxy-3-methyl-3,4,4a,9b-tetrahydrobenzofuro[3,2- b]pyridine-l(2H)-carboxylate isomer 2 (300 mg, 45% yield) as a yellow oil. MS ESI calculated for C18H24FNO4 [M+H]⁺, 338.17; found, 338.35.

Step 4:

A101

[1635] A solution of 7 :2 mixture of rel-tert-butyl (3R,4aS,9bS)-6-fluoro-7-methoxy-3- methyl-3,4,4a,9b-tetrahydrobenzofuro[3,2-b]pyridine-l(2H)-carboxylate isomer 1 and rel- tert-butyl (3R,4aS,9bS)-6-fluoro-7-methoxy-3-methyl-3,4,4a,9b-tetrahydrobenzofuro[3,2- b]pyridine-l(2H)-carboxylate isomer 2 (300 mg, 0.84 mmol) and HC1 (4M in dioxane) (5 mL) was stirred at room temperature for 3 h. The resulting mixture was concentrated under vacuum to afford a 7:2 mixture of rel-(3R,4aS,9bS)-6-fluoro-7-methoxy-3-methyl- l,2,3,4,4a,9b-hexahydrobenzofuro[3,2-b]pyridine isomer 1 and rel-(3R,4aS,9bS)-6-fluoro-7- methoxy-3-methyl-l,2,3,4,4a,9b-hexahydrobenzofuro[3,2-b]pyridine hydrochloride isomer 2 (A101) (320 mg, crude) MS ESI calculated for C13H16FNO2 [M+H]⁺, 238.12; found, 238.15. 'H NMR (400 MHz, DMSG ?) 5 10.73 (s, 1H), 9.21 (s, 1H), 7.48 - 7.37 (m, 1H), 6.87 - 6.74 (m, 1H), 4.97 - 4.86 (m, 1H), 4.85 - 4.57 (m, 1H), 3.86 (s, 3H), 3.26 - 3.10 (m, 1H), 2.61 - 2.54 and 2.39 - 2.29 (m, 1H), 2.28 - 2.16 (m, 1H), 2.07 - 1.88 (m, 1H), 1.81 - 1.60 (m, 1H), 1.08 - 0.98 (m, 3H).

Intermediate A101 isomer 1: rel-(3R,4aS,9bS)-6-fluoro-7-methoxy-3-methyl-l,2,3,4,4a,9b- hexahydrobenzofuro[3,2-b]pyridine isomer 1

A101 isomer 1 Intermediate A101 isomer 2: rel-(3R,4aS,9bS)-6-fluoro-7-methoxy-3-methyl-l,2,3,4,4a,9b- hexahydrobenzofuro[3,2-b]pyridine isomer 2

A101 isomer 2

[1636] A 7:2 mixture of rel-(3R,4aS,9bS)-6-fluoro-7-methoxy-3-methyl-l,2,3,4,4a,9b- hexahydrobenzofuro[3,2-b]pyridine isomer 1 and rel-(3R,4aS,9bS)-6-fluoro-7-methoxy-3- methyl-l,2,3,4,4a,9b-hexahydrobenzofuro[3,2-b]pyridine hydrochloride isomer 2 (A101) (270 mg) by prep-Chiral HPLC with the following conditions: [Column: CHIRALPAK IF, 2*25 cm, 5 pm; Mobile Phase A: Hex (0.5% 2M NH3-MeOH)-HPLC, Mobile Phase B: EtOH: DCM=1: 1— HPLC; Flow rate: 20 mL/min; Gradient (B%): isocratic 10% B to 10% in 21min% B; Wave Length: 220/254 nm; RTl(min): 10.49; RT2(min): 14.08; Sample Solvent: MeOH: DCM=1: 1-HPLC] to afford rel-(3R,4aS,9bS)-6-fhioro-7-methoxy-3-methyL l,2,3,4,4a,9b-hexahydrobenzofuro[3,2-b]pyridine isomer 1 (A101 isomer 1) (77 mg, 38% yield) as a white solid and rel-(3R,4aS,9bS)-6-fluoro-7-methoxy-3-methyl-l,2,3,4,4a,9b- hexahydrobenzofuro[3,2-b]pyridine isomer 2 (A101 isomer 2) (29 mg, 14% yield) as a white solid. [1637] rel-(3R,4aS,9bS)-6-fluoro-7-methoxy-3-methyl-l,2,3,4,4a,9b- hexahydrobenzofuro[3,2-b]pyridine isomer 1 (A101 isomer 1): MS ESI calculated for C13H16FNO2 [M+H]⁺, 238.12; found, 238.15. 'H NMR (300 MHz, DMSO-Jd) 8 7.03 - 6.89 (m, 1H), 6.71 - 6.52 (m, 1H), 4.75 - 4.65 (m, 1H), 4.48 (d, J = 8.0 Hz, 1H), 3.80 (s, 3H), 2.81 - 2.61 (m, 2H), 2.10 - 1.91 (m, 2H), 1.58 - 1.42 (m, 1H), 1.33 - 1.12 (m, 2H), 0.80 (d, J = 8.0 Hz, 3H). Absolute stereochemistry was not determined.

[1638] rel-(3R,4aS,9bS)-6-fluoro-7-methoxy-3-methyl-l,2,3,4,4a,9b- hexahydrobenzofuro[3,2-b]pyridine isomer 2 (A101 isomer 2): MS ESI calculated for C13H16FNO2 [M+H]⁺, 238.12; found, 238.15. 'H NMR (300 MHz, DMSO- ₆) 8 7.03 - 6.96 (m, 1H), 6.65 - 6.50 (m, 1H), 4.51 - 4.47 (m, 1H), 4.06 - 3.93 (m, 1H), 3.81 (s, 3H), 2.75 - 2.61 (m, 1H), 2.29 - 2.04 (m, 2H), 1.69 - 1.42 (m, 2H), 0.81 (d, J = 8.0 Hz, 3H). Absolute stereochemistry was not determined.

Intermediate A102 (2R,3R,4aS,9bS)-3-methoxy-2-methyl-7-(trifluoromethyl)- 1 , 2, 3, 4, 4a, 9b- hexahydrobenzofuro[3,2-b]pyridine

Step 1:

[1639] To a stirred solution of (R,E)-tert-butyl((2-methoxy-5-(4,4,5,5-tetramethyl-l,3,2- dioxaborolan-2-yl)pent-4-en-l-yI)oxy)dimethylsilane(20 g, 56.11 mmol) and l-bromo-2- fhioro-4-(trifluoromethyl)benzene (15.00 g, 61.73 mmol) in Dioxane (100 mL) and H2O (10 mL) were added K2CO3 (23.27 g, 168.35 mmol) and Pd(dppf)Ch (4.11 g, 5.61 mmol) at room temperature under nitrogen atmosphere. The resulting mixture was stirred at 100 °C overnight. The mixture was allowed to cool down to room temperature. The resulting mixture was diluted with water and extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SO4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-30% ethyl acetate in petroleum ether to afford (R,E)-tert-butyl(5-(2-fhioro-4- (trifhioromethyl)phenyl)-2-methoxypent-4-enyloxy)dimethylsilane (10 g, 45%) as a brown oil. MS ESI calculated for CuJ^ChSi [M+H]⁺, 393.18; found, 393.15.

Step 2:

[1640] To a stirred solution of (R,E)-tert-butyl(5-(2-fluoro-4-(trifluoromethyl)phenyl)-2- methoxypent-4-enyloxy)dimethylsilane (10 g, 25.47 mmol) in DMSO (30 mL) were added Dess-Martin periodinane (16.21 g, 38.21 mmol) and TsOH (0.44 g, 2.54 mmol) at room temperature under nitrogen atmosphere. The resulting mixture was stirred at 50 °C for 2 h. The mixture was allowed to cool down to room temperature. The resulting mixture was diluted with water and extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SO4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-30% ethyl acetate in petroleum ether to afford (R,E)-5-(2-fluoro-4- (trifhioromethyl)phenyl)-2-methoxypent-4-enal (5.7 g, 80%) as a brown oil. MS ESI calculated for C13H12F4O2 [M+H]⁺, 277.08; found, 277.05.

Step 3:

[1641] To a stirred solution of (R,E)-5-(2-fhioro-4-(trifluoromethyl)phenyl)-2- methoxypent-4-enal (5.7 g, 20.63 mmol) in THF (10 mL) was added MeMgBr (IM in THF) (80 mL, 80 mmol) dropwise at -78 °C under nitrogen atmosphere. The resulting mixture was stirred at room temperature overnight. The reaction was quenched with NH4CI (sat.) at 0 °C and extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous NazSCL. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-30% ethyl acetate in petroleum ether to afford a 1:1 mixture of (2S,3R,E)-6-(2-fhioro-4-(trifluoromethyl)phenyl)- 3-methoxyhex-5-en-2-ol and (2R,3R,E)-6-(2-fhioro-4-(trifluoromethyl)phenyl)-3- methoxyhex-5-en-2-ol (2 g, 33%) as a colorless oil. MS ESI calculated for C14H16F4O2 [M+H]⁺, 293.11; found, 293.10.

Step 4:

[1642] To a solution of (2S,3R,E)-6-(2-fluoro-4-(trifluoromethyl)phenyl)-3-methoxyhex-5- en-2-ol (2 g, 6.84 mmol) in DCM (10 mL) was added Dess-Martin periodinane (4.35 g, 10.26 mmol) at room temperature. The mixture was stirred at room temperature overnight. The reation mixture was quenched by water and extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous NazSO4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-30% ethyl acetate in petroleum ether to afford (R,E)-6-(2- fluoro-4-(trifluoromethyl)phenyl)-3-methoxyhex-5-en-2-one (1 g, 50%) as a yellow oil. MS ESI calculated for C14H14F4O2 [M+H]⁺, 291.09; found, 291.10.

Step 5:

[1643] To a stirred solution of NaOH (0.28 g, 6.88 mmol) in H2O (400 mL) was added a solution of tert-butyl carbamate (0.93 g, 7.90 mmol) in propan- l-ol (400 mL), thne 1,3- dichloro-5,5-dimethylimidazolidine-2, 4-dione (1.00 g, 5.09 mmol) was added in portions at room temperature. After stirring at room temperature for 0.5 h, this was followed by the addition of a solution of (DHQ)2PHAL (supplier: Shanghai Accela ChemBio Co., Ltd. CAS# 140924-50-1) (0.20 g, 0.25 mmol) in propan-l-ol (400 mL), a solution of (R,E)-6-(2-fluoro- 4-(trifluoromethyl)phenyl)-3-methoxyhex-5-en-2-one (1 g, 2.54 mmol) in propan-l-ol (400 mL) and a mixture of Potassium osmate(VI) dihydrate (0.09 g, 0.25 mmol) in NaOH (aq, 0.4 M, 1 mL) at 0 °C. The resulting mixture was stirred at room temperature for additional 16 h. The resulting mixture was concentrated under reduced pressure. The residue was dissolved in H2O (400 mL) and extracted with DCM. The organic layer was dried over anhydrous Na2SO4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-30% ethyl acetate in petroleum ether to afford (lS,2S,4R)-l-(2-fluoro-4-(trifluoromethyl)phenyl)-2-hydroxy-4- methoxy-5-oxohexylcarbamate (1 g, 92%) as a yellow oil. MS ESI calculated for C19H25F4NO5 [M+H]⁺, 434.17; found, 434.17.

Step 6:

[1644] To a solution of tert-butyl (lS,2S,4R)-l-(2-fhioro-4-(trifluoromethyl)phenyl)-2- hydroxy-4-methoxy-5-oxohexylcarbamate (1 g, 2.36 mmol) in DCM (10 mL) was added TFA (5 mL) at room temperature. The mixture was stirred at room temperature for 2 h. The residue was basified with saturated NaOH (aq.) to pH 8 and extracted with DCM. The combined organic layers were washed with brine, dried over anhydrous NaiSCh. After filtration, the filtrate was concentrated under reduced pressure. The residue was dissolved in i-PrOH (10 mL), then Pd/C (500 mg, 10% active on carbon) was added at room temperature. The mixture was stirred at room temperature for 2 h under hydrogen atmosphere. The resulting mixture was filtered, the filter cake was washed with i-PrOH (10 mL). The filtrate was concentrated under reduced pressure to afford (2S,3S,5R,6R)-2-(2-fluoro-4- (trifhioromethyl)phenyl)-5-methoxy-6-methylpiperidin-3-ol (400 mg, 55%) as a colorless oil. MS ESI calculated for C14H17F4NO2 [M+H]⁺, 308.12; found, 308.10.

Step 7:

[1645] To a solution of (2S,3S,5R,6R)-2-(2-fluoro-4-(trifluoromethyl)phenyl)-5-methoxy- 6-methylpiperidin-3-ol (400 mg, 1.30 mmol) in tert- Amyl alcohol (4 mL) was added t-BuOK (292 mg, 2.60 mmol) at room temperature. The mixture was stirred at 60 °C for 16 h. The reaction was quenched by water and extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SO4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 50-80% ethyl acetate in petroleum ether to afford (2R,3R,4aS,9bS)-3-methoxy-2-methyl-7-(trifluoromethyl)-l,2,3,4,4a,9b- hexahydrobenzofuro[3,2-b]pyridine (A102) (100 mg, 26%) as a yellow oil. MS ESI calculated for C14H16F3NO2 [M+H]⁺, 288.11; found, 288.10. ’H NMR (400 MHz, DMSO) 5 7.53 (d, J = 7.6 Hz, 1H), 7.21 (d, J = 8.0 Hz, 1H), 7.15 (d, J= 1.6 Hz, 1H), 4.40 (t, J = 5.2 Hz, 1H), 4.27 - 4.16 (m, 1H), 3.30 (s, 3H), 3.15 (t, J = 3.2 Hz, 1H), 2.80 (d, J = 7.2 Hz, 1H), 2.61 (d, J = 16.0 Hz, 1H), 1.97 (d, J = 15.6 Hz, 1H), 1.04 - 0.93 (m, 3H). Absolute stereochemistry was determined by NOESY.

Intermediate A103 (2R,3R,4aS,9bS)-7-chloro-3-methoxy-2-methyl-l,2,3,4,4a,9b- hexahydrobenzofuro[3,2-b]pyridine

Step-1:

[1646] To a solution of (R, E)-tert-butyl((2-methoxy-5-(4, 4,5, 5-tetramethyl- 1,3,2- dioxaborolan-2-yl)pent-4-en-l-yl)oxy)dimethylsilane (20.00 g, 56.12 mmol), l-bromo-4- chloro-2-fluorobenzene (10.68 g, 51.02 mmol) and K2CO3 (21.15 g, 153.05 mmol) in 1,4- dioxane (200 mL) and H2O (20 mL) were added Pd(dppf)C12-CH2C12 (4.17 g, 5.10 mmol). The mixture was stirred at 100 °C for 16 h. The mixture was allowed to cool down to room temperature and concentrated under vacuum. The residue was purified by silica gel column chromatography, eluted with 0-10% ethyl acetate in petroleum ether to afford (R,E)-tert- butyl((5-(4-chloro-2-fluorophenyl)-2-methoxypent-4-en- 1 -yl)oxy)dimethylsilane ( 16.00 g, 87%) as a yellow oil. MS ESI calculated for CisI^sClFChSi [M+H]⁺, 359.15; found, 359.15.

Step-2:

[1647] To a solution of (R,E)-tert-butyl((5-(4-chloro-2-fluorophenyl)-2-methoxypent-4-en- l-yl)oxy)dimethylsilane (16.00 g, 44.57 mmol) in DMSO (160 mL) were added Dess-Martin periodinane (28.36 g, 66.86 mmol) and 4-methylbenzene-l -sulfonic acid hydrate (850 mg, 4.45 mmol). The mixture was stirred at room temperature for 16 h. The reaction was quenched by the addition of water at 0 °C. The resulting mixture was extracted with EtOAc. The combined organic layers were dried over anhydrous NaiSC After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-17% ethyl acetate in petroleum ether to afford (R,E)-5-(4- chloro-2-fhiorophenyl)-2-methoxypent-4-enal (10.20 g, 94%) as a colorless oil. MS ESI calculated for C12H12CIFO2 [M+H]⁺, 243.05; found, 243.10.

Step-3:

[1648] To a solution of (R,E)-5-(4-chloro-2-fluorophenyl)-2-methoxypent-4-enal (10.50 g, 43.27 mmol) in THF (100 mL) was added methylmagnesium bromide (1.0 M in THF, 130 mL) dropwise at -78 °C. The mixture was stirred at room temperature for 16 h under nitrogen atmosphere. The reaction was quenched by the addition of NH4CI (sat.) at 0 °C. The resulting mixture was extracted with EtOAc. The combined organic layers were washed with water, dried over anhydrous Na2SO4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-20% ethyl acetate in petroleum ether to afford a 1:1 mixture of (2S,3R,E)-6-(4-chloro-2- fluorophenyl)-3-methoxyhex-5-en-2-ol and (2R,3R,E)-6-(4-chloro-2-fluorophenyl)-3- methoxyhex-5-en-2-ol (5.80 g, 52%) as a yellow oil. MS ESI calculated for C13H16CIFO2 [M+H]⁺, 259.08; found, 259.10.

Step-4:

[1649] To a solution of 1: 1 mixture of (2S,3R,E)-6-(4-chloro-2-fluorophenyl)-3- methoxyhex-5-en-2-ol and (2R,3R,E)-6-(4-chloro-2-fluorophenyl)-3-methoxyhex-5-en-2-ol (5.80 g, 22.42 mmol) in DCM (60 mL) was added Dess-Martin periodinane (14.26 g, 33.63 mmol). The mixture was stirred at room temperature for 16 h. The reaction was quenched by the addition of water at 0 °C and extracted with EtOAc. The combined organic layers were dried over anhydrous Na2SO4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-10% ethyl acetate in petroleum ether to afford (R,E)-6-(4-chloro-2-fluorophenyl)-3-methoxyhex-5- en-2-one (4.80 g, 83%) as a yellow oil. MS ESI calculated for C13H14CIFO2 [M+H]⁺, 257.07; found, 257.05.

Step-5:

[1650] To a solution of NH2B0C (6.89 g, 58.81 mmol) in propan-l-ol (145 mL) was added

NaOH (4 M in H20, 126 mL). The mixture was stirred at room temperature for 10 min. Then DCDMH (5.61 g, 28.46 mmol) was added, the mixture was stirred at room temperature for 30 min. This was followed by the addition of a solution of (DHQ)2PHAL (supplier: Shanghai Accela ChemBio Co., Ltd. CAS# 140924-50-1) (1.48 g, 1.90 mmol) in propan-l-ol (19 mL), a solution of (R,E)-6-(4-chloro-2-fluorophenyl)-3-methoxyhex-5-en-2-one (4.87 g, 18.97 mmol) in propan-l-ol (19 mL) and Potassium osmate(VI) dihydrate (0.70 g, 1.90 mmol) at 0 °C. The mixture was stirred at room temperature for 16 h. The resulting mixture was diluted with water. The aqueous layer was extracted with EtOAc. The residue was purified by silica gel column chromatography, eluted with 0-35% ethyl acetate in petroleum ether to afford tert-butyl ((IS ,2S,4R)- 1 -(4-chloro-2-fluorophenyl)-2-hydroxy-4-methoxy-5- oxohexyl)carbamate (4.90 g, 66%) as a colorless oil. MS ESI calculated for C18H25CIFNO5 [M+H]⁺, 390.14; found, 390.10.

Step-6:

[1651] To a solution of tert-butyl ((lS,2S,4R)-l-(4-chloro-2-fhiorophenyl)-2-hydroxy-4- methoxy-5-oxohexyl)carbamate (4.90 g, 12.57 mmol) in DCM (50 mL) was added TFA (15 mL, 0.13 mmol). The mixture was stirred at room temperature for 1 h. The resulting mixture was concentrated under vacuum. The residue was dissolved in i-PrOH (80 mL), then Pt/C (5% active on carbon) (3.05 g) was added. The mixture was stirred at room temperature for 16 h under hydrogen atmosphere. The mixture was filtered. The filtrate was diluted by Na2HCC>3 (aq.) and extracted with EtOAc. The organic layer was dried over anhydrous Na2SO4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by reverse phase flash column chromatography with 5% to 50% MeCN in Water (10 mmol/L NH4HCO3) to afford (2S,3S,5R,6R)-2-(4-chloro-2-fluorophenyl)-5-methoxy-6- methylpiperidin-3-ol (620 mg, 6%) as a colorless oil. MS ESI calculated for C13H17CIFNO2 [M+H]⁺, 274.09; found, 274.10.

Step-7:

[1652] To a solution of (2S,3S,5R,6R)-2-(4-chloro-2-fluorophenyl)-5-methoxy-6- methylpiperidin-3-ol (587 mg, 2.14 mmol) in THF (2 mL) was added t-BuOK (481 mg, 4.29 mmol). The mixture was stirred at 70 °C for 5 h. The resulting mixture was diluted with water and extracted with EtOAc. The combined organic layers dried over anhydrous Na2SC>4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by reverse phase flash column chromatography with 5% to 50% MeCN in Water (10 mmol/L NH4HCO3) to afford (2R,3R,4aS,9bS)-7-chloro-3-methoxy-2-methyl-l,2,3,4,4a,9b- hexahydrobenzofuro[3,2-b]pyridine (A103) (240 mg, 44%) as a yellow oil. MS ESI calculated for CI₃HI₆C1NO₂ [M+H]⁺, 254.09; found, 254.10. 'H NMR (400 MHz, DMSO-d₆) 6 7.30 (d, J= 7.6 Hz, IH), 6.96 - 6.83 (m, 2H), 4.61 (q, 7 = 4.8 Hz, 1H), 4.10 (d, J= 5.2 Hz, 1H), 3.28 (s, 3H), 2.99 - 2.91 (m, IH), 2.49 - 2.39 (m, IH), 2.07 - 1.92 (m, 1H), 1.85 - 1.72 (m, IH), 1.01 (d, J = 6.4 Hz, 3H). Absolute stereochemistry was determined by NOESY.

Intermediate A104: (3R,4aR*,9bR*)-7-(difluoromethoxy)-3-methoxy- 1,2, 3, 4, 4a, 9b- hexahydrofuro[2,3-b:4,5-b']dipyridine

Step 1:

[1653] To a stirred solution of (R,E)-tert-butyl((2-methoxy-5-(4,4,5,5-tetramethyl-l,3,2- dioxaborolan-2-yl)pent-4-en-l-yl)oxy)dimethylsilane (8.04 g, 30.87 mmol) in Dioxane (200 mL) and H2O (20 mL) were added K2CO3 (23.27 g, 168.35 mmol), 3-bromo-2-chloro-6- (difluoromethoxy)pyridine (7.93 g, 30.87 mmol) and Pd(dppf)Ch (4.11 g, 5.62 mmol) at room temperature under nitrogen atmosphere. The resulting mixture was heated to 100 °C with stirring for 16 h. The mixture was allowed to cool down to room temperature. The resulting mixture was diluted with water. The resulting mixture was extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SC>4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-20% ethyl acetate in petroleum ether to afford (R,E)-3-(5-((tert-butyldimethylsilyl)oxy)-4-methoxypent- 1 -en- 1 -yl)-2-chloro-6- (difluoromethoxy)pyridine (21.00 g, 99%) as a brown oil. MS ESI calculated for Ci₈H28ClF2NO₃Si [M+H]⁺, 408.15 ; found, 408.10.

Step 2:

[1654] To a stirred solution of NaOH (5.45 g, 1 6.34 mmol) in H2O (340 mL) was added a solution of tert-butyl carbamate (18.34 g, 156.54 mmol) in propan-l-ol (391 mL), then 1,3- dichloro-5,5-dimethylimidazolidine-2, 4-dione (19.90 g, 100.99 mmol) was added in portions at room temperature under nitrogen atmosphere.After stirring at room temperature for 0.5 hour, this was followed by the addition of a solution of (DHQ)2PHAL (supplier: Shanghai Accela ChemBio Co., Ltd. CAS# 140924-50-1) (3.93 g, 5.05 mmol) in propan-l-ol (51 mL), a solution of (R,E)-3-(5-((tert-butyldimethylsilyl)oxy)-4-methoxypent-l-en-l-yl)-2-chloro-6- (difluoromethoxy)pyridine (20.60 g, 50.25 mmol) in propan-l-ol (51 mL) and Potassium osmate(VI) dihydrate (1.86 g, 5.05 mmol) at 0 °C. The resulting mixture was stirred at room temperature overnight. The resulting mixture was concentrated under reduced pressure. The residue was dissolved in H2O and extracted with DCM. The combined organic layers were washed with brine, dried over anhydrous Na2SC>4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-10% ethyl acetate in petroleum ether to afford tert-butyl ((lS*,2S*,4R)-5-((tert-butyldimethylsilyl)oxy)-l-(2-chloro-6-(difluoromethoxy)pyridin-3- yl)-2-hydroxy-4-methoxypentyl)carbamate (13.00 g, 45%) as a yellow oil. MS ESI calculated for C23H39ClF₂N2O₆Si [M+H]⁺, 541.22 ; found, 541.20.

Step 3:

[1655] To a solution of tert-butyl ((lS*,2S*,4R)-5-((tert-butyldimethylsilyl)oxy)-l-(2- chloro-6-(difluoromethoxy)pyridin-3-yl)-2-hydroxy-4-methoxypentyl)carbamate (13.00 g, 24.02 mmol) in Toluene (150 mL) were added Pd(OAc)2 (1.08 g, 4.80 mmol), JohnPhos (1.43 g, 4.81 mmol) and CS2CO3 (23.48 g, 72.07 mmol) at room temperature. The resulting mixture was stirred at 100 °C for 16 h under nitrogen atmosphere. The resulting mixture was concentrated under reduced pressure. The residue was dissolved in H2O and extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SO4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-10% ethyl acetate in petroleum ether to afford tert-butyl ((2S*,3S*)-2-((R)-3-((tert-butyldimethylsilyl)oxy)-2-methoxypropyl)-6- (difhioromethoxy)-2,3-dihydrofuro[2,3-b]pyridin-3-yl)carbamate (8.7 g, 71%) as a yellow oil. MS ESI calculated for C23H₃₈F2N2O6Si [M+H]⁺, 505.25 ; found, 505.20.

[1656] To a solution of tert-butyl ((2S*,3S*)-2-((R)-3-((tert-butyldimethylsilyl)oxy)-2- methoxypropyl)-6-(difhioromethoxy)-2,3-dihydrofuro[2,3-b]pyridin-3-yl)carbamate (8.7 g, 17.24 mmol) in THF (100 mL) was added TBAF (9.02 g, 34.48 mmol). The mixture was stirred at room temperature for 2 hours. The reaction was quenched by water and extracted with EtOAc. The resulting mixture was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-10% MeOH in CH2CI2 to afford tert-butyl ((2S*,3S*)-6-(difluoromethoxy)-2-((R)-3-hydroxy-2-methoxypropyl)-2,3- dihydrofuro[2,3-b]pyridin-3-yl)carbamate (5.8 g, 86%) as a pink solid. MS ESI calculated for C17H24F2N2O6 [M+H]⁺, 391.16 ; found, 391.10.

Step 5:

[1657] A solution of tert-butyl ((2S*,3S*)-6-(difluoromethoxy)-2-((R)-3-hydroxy-2- methoxypropyl)-2,3-dihydrofuro[2,3-b]pyridin-3-yl)carbamate (5.8 g, 14.86 mmol) and CMBP (7.17 g, 29.71 mmol) in Toluene (60 mL) was stirred at 100°C for 16 h under nitrogen atmosphere. The resulting mixture was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-30% ethyl acetate in petroleum ether to afford tert-butyl (3R,4aS*,9bS*)-7-(difluoromethoxy)-3-methoxy-3,4,4a,9b- tetrahydrofuro[2,3-b:4,5-b']dipyridine-l(2H)-carboxylate (4.3 g, 61%) as a yellow oil. MS ESI calculated for C17H22F2N2O5 [M+H]⁺, 373.15 ; found, 373.10.

[1658] A mixture of tert-butyl (3R,4aS*,9bS*)-7-(difluoromethoxy)-3-methoxy-3,4,4a,9b- tetrahydrofuro[2,3-b:4,5-b']dipyridine-l(2H)-carboxylate (4.3 g, 11.55 mmol) and HCl (g) (4M in 1,4-dioxane, 50 mL) was stirred at room temperature for 1 hours. The resulting mixture was concentrated under reduced pressure. The residue was dissolved with DCM (50 mL) and MeOH (5 mL), then K2CO3 (4.78 g, 34.65 mmol) as added. The resulting mixture was stirred at room temperature for 1 hours. The resulting mixture was filtered, the filter cake was washed with DCM (50 mL). The filtrate was concentrated under reduced pressure and afford (3R,4aS*,9bS*)-7-(difluoromethoxy)-3-methoxy-l,2,3,4,4a,9b-hexahydrofuro[2,3- b:4,5-b']dipyridine (A104) (3.4 g, 97%) as a brown oil. MS ESI calculated for C12H14F2N2O3 [M+H]⁺, 273.10; found, 275.05. 'H NMR (300 MHz, DMSO) 57.88 - 7.29 (m, 2H), 6.56- 6.49 (m, 1H), 4.98 - 4.63 (m, 1H), 4.40 - 4.30 (m, 1H), 3.31 - 3.25 (m, 1H), 3.21 (d, J = 3.2 Hz, 3H), 2.97 - 2.77 (m, 1H), 2.44 - 2.08 (m, 2H), 2.05 - 1.40 (m, 2H). Absolute stereochemistry was not determined.

Intermediate A106 isomer 1: (3R,4aS,9bS)-3-methyl-7-(trifluoromethyl)-l ,2,3,4,4a,9b- hexahydrofuro[2,3-b:4,5-b']dipyridine isomerl

Intermediate A106 isomer 2: (3S,4aS,9bS)-3-methyl-7-(trifluoromethyl)-l,2,3,4,4a,9b- hexahydrofuro[2,3-b:4,5-b']dipyridine

[1659] To a stirred solution of 3-bromo-2-chloro-6-(trifluoromethyl)pyridine (5.0 g, 19.20 mmol) in toluene (50 mL) were added tert-butyl 3-methyl-5-oxopiperidine-l-carboxylate (8.19 g, 38.40 mmol), P(t-Bu)₃Pd G3 (981 mg, 1.92 mmol) and K3PO4 (10.19 g, 47.99 mmol) at 25 °C. The resulting solution was stirred at 90 °C for 1 h under nitrogen atmosphere. The reaction was quenched with water and extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered through paper, and concentrated under vacuum. The residue was purified by silica gel column chromatography, eluted with 0 - 40% EtOAc in petroleum ether to afford a 1 : 1 : 1 : 1 mixture of tert-butyl (2S,5R)-2-(2-chloro-6-(trifluoromethyl)pyridin-3-yl)-5-methyl-3-oxopiperidine-l- carboxylate and tert-butyl (2R,5S)-2-(2-chloro-6-(trifhioromethyl)pyridin-3-yl)-5-methyl-3- oxopiperidine-1 -carboxylate and tert-butyl (2S,5S)-2-(2-chloro-6-(trifluoromethyl)pyridin-3- yl)-5-methyl-3-oxopiperidine-l -carboxylate and tert-butyl (2R,5R)-2-(2-chloro-6- (trifhioromethyl)pyridin-3-yl)-5-methyl-3-oxopiperidine-l-carboxylate (3.50 g, 19%) as a yellow oil. MS ESI calculated for C17H20CIF3N2O3 [M+H]⁺, 393.11; found, 393.05.

Step-2: [1660] To a stirred solution of 1 : 1 : 1 : 1 mixture of tert-butyl (2S,5R)-2-(2-chloro-6- (trifhioromethyl)pyridin-3-yl)-5-methyl-3-oxopiperidine- 1 -carboxylate and tert-butyl (2R,5S)-2-(2-chloro-6-(trifluoromethyl)pyridin-3-yl)-5-methyl-3-oxopiperidine-l- carboxylate and tert-butyl (2S,5S)-2-(2-chloro-6-(trifluoromethyl)pyridin-3-yl)-5-methyl-3- oxopiperidine-1 -carboxylate and tert-butyl (2R,5R)-2-(2-chloro-6-(trifluoromethyl)pyridin-3- yl)-5-methyl-3-oxopiperidine-l -carboxylate (3.52 g, 8.91 mmol) in MeCN (40 mL) were added RuCl[(S,S-TsDPEN)](p-cymene) (142 mg, 0.22 mmol), HCOOH (1.24 g, 26.73 mmol) and DABCO (5.53 g, 49.00 mmol) at 0 °C. The resulting solution was stirred at 25 °C for 16 h. The resulting mixture was quenched by the addition of NaHCCh (sat.) and extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered and concentrated under vacuum. The residue was purified by silica gel column chromatography, eluted with 0 - 20% EtOAc in petroleum ether to afford a 1 : 1 mixture of tert-butyl (2S,3S,5R)-2-(2-chloro-6-(trifluoromethyl)pyridin-3-yl)-3-hydroxy-5- methylpiperidine-1 -carboxylate and tert-butyl (2S,3S,5S)-2-(2-chloro-6- (trifhioromethyl)pyridin-3-yl)-3-hydroxy-5-methylpiperidine-l-carboxylate (1.50 g, 50%) as a white solid. MS ESI calculated for C17H22CIF3N2O3 [M+H]⁺, 395.13 ;found, 395.20.

Step-3:

[1661] To a stirred solution of 1 : 1 mixture of tert-butyl (2S,3S,5R)-2-(2-chloro-6- (trifluoromethyl)pyridin-3-yl)-3-hydroxy-5-methylpiperidine- 1 -carboxylate and tert-butyl (2S,3S,5S)-2-(2-chloro-6-(trifluoromethyl)pyridin-3-yl)-3-hydroxy-5-methylpiperidine-l- carboxylate (1.50 g, 3.80 mmol) in THF (20 mL) was added t-BuOK (639 mg, 5.70 mmol) at 25 °C. The resulting solution was stirred at 25 °C for 16 h. The reaction mixture was quenched by the addition of water and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered through paper, and concentrated under vacuum. The residue was purified by silica gel column chromatography, eluted with 0 - 30% EtOAc in petroleum ether, then purified by prep-chiral SFC with the following conditions: [Column: CHIRALPAK IF 3*25 cm, 5 pm; Mobile Phase A: CO2, Mobile Phase B: MeOH; Flow rate: 100 mL/min; Gradient (B%): isocratic 20% B; RTl(min): 2.5; RT2(min): 4; Sample Solvent: MEOH; Injection Volume: 2 mL; Number Of Runs: 15] to afford tert-butyl (3R,4aS,9bS)-3-methyl-7-(trifluoromethyl)-3,4,4a,9b- tetrahydrofuro[2,3-b:4,5-b']dipyridine-l(2H)-carboxylate isomer 1 (420 mg, 43%) as a yellow solid with retention time at 4.0 minutes. MS ESI calculated for C17H21CIF3N2O3 [M+H]⁺, 359.15 ; found, 359.10.

[1662] The chiral resolution also affords tert-butyl (3S,4aS,9bS)-3-methyl-7- (trifhioromethyl)-3,4,4a,9b-tetrahydrofuro[2,3-b:4,5-b']dipyridine-l(2H)-carboxylate isomer 2 (410 mg, 45%) as a yellow solid with retention time at 2.5 minutes. ESI calculated for C17H21CIF3N2O3 [M+H]⁺, 359.15;found, 359.10.

Step-5:

[1663] A mixture of tert-butyl (3R,4aS,9bS)-3-methyl-7-(trifluoromethyl)-3,4,4a,9b- tetrahydrofuro[2,3-b:4,5-b']dipyridine-l(2H)-carboxylate (420 mg, 1.17 mmol) and hydrogen chloride (4.0 M in ethyl acetate) (5 mL) was stirred at room temperature for 1 h. The resulting mixture was concentrated under vacuum to afford (3R,4aS,9bS)-3-methyl-7- (trifhioromethyl)-l,2,3,4,4a,9b-hexahydrofuro[2,3-b:4,5-b']dipyridine hydrochloride isomer 1 (A106 isomerl) (400 mg, crude) as a yellow solid. MS ESI calculated for C12H13F3N2O [M+H]⁺, 259.10; found, 259.05. NMR (300 MHz, DMSO) 5 10.81 (s, 1H), 9.65 (s, 1H), 8.38 (d, J = 7.5 Hz, 1H), 7.60 (d, J = 7.5 Hz, 1H), 5.29 - 4.94 (m, 2H), 3.30 - 3.17 (m, 1H), 2.75 - 2.58 (m, 1H), 2.36 - 2.21 (m, 1H), 2.10 - 1.95 (m, 2H), 1.79 - 1.54 (m, 1H), 1.01 (d, J - 6.6 Hz, 3H). Absolute stereochemistry was determined by NOESY. Step-6:

[1664] A mixture of tert-butyl (3S,4aS,9bS)-3-methyl-7-(trifluoromethyl)-3,4,4a,9b- tetrahydrofuro[2,3-b:4,5-b']dipyridine-l(2H)-carboxylate (400 mg, 1.12 mmol) and hydrogen chloride(4.0 M in ethyl acetate) (4 mL) was stirred at room temperature for 1 h. The resulting mixture was concentrated under vacuum to afford (3S,4aS,9bS)-3-methyl-7- (trifhioromethyl)-l,2,3,4,4a,9b-hexahydrofuro[2,3-b:4,5-b']dipyridine hydrochloride isomer 2 (A106, isomer2) (350 mg, crude) as a yellow solid. MS ESI calculated for C12H13F3N2O [M+H]⁺, 259.10; found, 259.05. 'H NMR (300 MHz, DMSO) 8 11.04 (s, 1H), 8.91 (s, 1H), 8.26 (d, J = 7.5 Hz, 1H), 7.61 (d, J= 7.5 Hz, 1H), 5.03 - 4.80 (m, 2H), 3.08 (d, J= 12.6 Hz, 1H), 2.63 - 2.62 (m, 1H), 2.36 (d, J = 15.0 Hz, 1H), 2.09 - 1.52 (m, 2H), 0.99 (d, J= 6.6 Hz, 3H). Absolute stereochemistry was determined by NOESY.

Intermediate A107: (4aS ,6R, 10bS)-8-(difluoromethoxy)-6-methyl-2,3 ,4, 4a, 6, 1 Ob- hexahydro- 1 H-pyrano [3 ,2-b : 5 ,4-b '] dipyridine

Step-1:

[1665] To a stirred solution of tert-butyl (4aS,6R,10bS)-8-chloro-6-methyl-2,3,4,4a,6,10b- hexahydro-lH-pyrano[3,2-b:5,4-b']dipyridine-l-carboxylate (from A78) (300 mg, 0.89 mmol) and KOH (99 mg, 1.77 mmol) in Dioxane (5 mL) and H2O (1 mL) were added t- BuXPhos (38 mg, 0.09 mmol) and Pd2(dba)s (81 mg, 0.09 mmol) at room temperature under nitrogen atmosphere. The resulting mixture was stirred at 100 °C for 16 h. The resulting mixture was concentrated under vacuum. The residue was purified by normal phase flash column chromatography which applied to 40 g silica gel column eluted with 0-15% methanol in dichloromethane to afford tert-butyl (4aS,6R,10bS)-8-hydroxy-6-methyl-2,3,4,4a,6,10b- hexahydro-lH-pyrano[3,2-b:5,4-b']dipyridine-l-carboxylate (254 mg, 90% yield) as a yellow solid. MS ESI calculated for C17H24N2O4 [M+H]⁺, 321.17; found, 321.15.

Step-2:

[1666] To a stirred solution of tert-butyl (4aS,6R,10bS)-8-hydroxy-6-methyl- 2,3,4,4a,6,10b-hexahydro-lH-pyrano[3,2-b:5,4-b']dipyridine-l-carboxylate (250 mg, 0.78 mmol) and K2CO3 (129 mg, 0.94 mmol) in DMF (5 mL) was added sodium chlorodifluoroacetate (238 mg, 1.56 mmol) at room temperature. The resulting mixture was stirred at 90 °C for 2 h. The reaction mixture was quenched by the addition of water and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under vacuum. The resulting residue was purified by normal phase flash column chromatography which applied to 25 g silica gel column eluted with 0-15% ethyl acetate in petroleum ether to afford tert-butyl (4aS,6R,10bS)-8-(difluoromethoxy)-6-methyl-2,3,4,4a,6,10b-hexahydro-lH-pyrano[3,2- b:5,4-b']dipyridine-l-carboxylate (160 mg, 55% yield) as a light yellow oil. MS ESI calculated for C18H24F2N2O4 [M+H]⁺, 371.17; found, 371.20.

Step-3:

[1667] A solution of tert-butyl (4aS,6R,10bS)-8-(difluoromethoxy)-6-methyl- 2,3,4,4a,6,10b-hexahydro-lH-pyrano[3,2-b:5,4-b^,]dipyridine-l-carboxylate (160 mg, 0.43 mmol) and HC1 (4.0 M in 1,4-dioxane) (2 mL) was stirred at room temperature for 2 h. The resulting mixture was concentrated under vacuum to afford (4aS,6R,10bS)-8- (difluoromethoxy)-6-methyl-2,3 ,4, 4a, 6, 1 Ob-hexahydro- IH-pyrano [3 ,2-b:5 ,4-b'] dipyridine hydrochloride (A107) (crude, 103 mg) as a white solid. MS ESI calculated for C13H16F2N2O2 (M+H]⁺, 271.12; found, 271.15. 'H NMR (400 MHz, DMSO) 5 10.52 (s, 1H), 8.63 (br, 1H), 8.23 (dd, J= 8.8, 1.6 Hz, 1H), 7.96 - 7.58 (m, 1H), 7.10 (d, J = 8.4 Hz, 1H), 4.85 - 4.75 (m, 1H), 4.37 (d, J = 10.4 Hz, 1H), 4.06 (d, J = 2.4 Hz,lH), 3.20 (d, J= 12.4 Hz, 1H), 3.02 (d, J = 11.4 Hz, 1H), 2.09 - 1.77 (m, 3H), 1.73 - 1.39 (m, 4H).

Intermediate A108: (3R,4aR*,10bR*)-8-(difluoromethoxy)-3-methoxy-2,3,4,4a,6,10b- hexahydro- 1 H-pyrano [3 ,2-b : 5 ,4-b '] dipyridine

Step-1:

[1668] To a stirred solution of methyl 3-bromo-6-(difhioromethoxy)picolinate (17.20 g, 61.98 mmol) in 1,4-dioxane (200 mL) and H2O (20 mL) were added (R,E)-tert-butyl((2- methoxy-5-(4,4,5,5-tetramethyl-l,3,2-dioxaborolan-2-yl)pent-4-en-l-yl)oxy)dimethylsilane (23.91 g, 67.08 mmol), Pd(dppf)Cl₂-CH₂C12 (4.98 g, 6.10 mmol) and K2CO3 (25.28 g, 182.95 mmol) at room temperature. The resulting mixture was stirred at 100 °C for 16 h. The resulting mixture was diluted with water and extracted with EtOAc. The combined organic layers were dried over anhydrous Na2SC>4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-20% ethyl acetate in petroleum ether to afford methyl (R,E)-3-(5-((tert- butyldimethylsilyl)oxy)-4-methoxypent- 1 -en- 1 -yl)-6-(difluoromethoxy)picolinate (4.50 g, 45%) as a brown oil. MS ESI calculated for C2oH3iF2NOsSi [M+H]⁺, 432.19; found 432.20.

Step-2:

[1669] To a mixture of B0CNH2 (3.79 g, 32.32 mmol) in n-PrOH (40 mL) were added a solution of NaOH (1.13g, 24.29mmol) in H2O (34 mL). After stirring at room temperature for 10 minutes, l,3-dichloro-5,5-dimethylimidazolidine-2, 4-dione (3.08 g, 15.64 mmol) was added at room temperature. The resulting mixture was stirred at room temperature for additional 30 min. This was followed by the addition of a solution of (DHQ)2PHAL (supplier: Shanghai Accela ChemBio Co., Ltd. CAS# 140924-50-1) (0.81 g, 1.04 mmol) in n- PrOH (9 mL), a solution of methyl (R,E)-3-(5-((tert-butyldimethylsilyl)oxy)-4-methoxypent- l-en-l-yl)-6-(difluoromethoxy)picolinate (4.50 g, 10.43 mmol) in propan-l-ol (45 mL) and Potassium osmate(VI) dihydrate (0.38 g, 1.04 mmol) at 0 °C. The resulting mixture was stirred at room temperature for 16 h. The mixture was diluted with water and extracted with EtOAc. The combined organic layers were dried over anhydrous NazSCL. After filtration, the filtrate was concentrated under reduced pressure.

[1670] The residue was dissolved in DCM (65mL), then DCC (6.43 g, 31.16 mmol) and DMAP (6.92 g, 56.66 mmol) were added at room temperature. The resulting mixture was stirred at room temperature for 16 h. The resulting mixture was diluted with water and extracted with DCM. The combined organic layers were dried over anhydrous NazSCL. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0 - 30% EtOAc in petroleum ether to afford tert-butyl ((5R*,6R*)-6-((R)-3-((tert-butyldimethylsilyl)oxy)-2-methoxypropyl)-2- (difhjoromethoxy)-8-oxo-5,8-dihydro-6H-pyrano[3,4-b]pyridin-5-yl)carbamate (3.0 g, 22%) as a yellow solid. MS ESI calculated for (Cz^asFzNzOzSi) [M+H]⁺, 533.24; found: 533.25.

Step-3:

[1671] To a stirred solution of tert-butyl ((5R*,6R*)-6-((R)-3-((tert- butyldimethylsilyl)oxy)-2-methoxypropyl)-2-(difluoromethoxy)-8-oxo-5,8-dihydro-6H- pyrano[3,4-b]pyridin-5-yl)carbamate (3.0 g, 5.63 mmol) in THF (30 mL) was added NaBFL (320 mg, 8.45 mmol) at 0 °C. The resulting mixture was stirred at room temperature for 16 h. The reaction was quenched with water and extracted with EtOAc. The combined organic layers were dried over anhydrous NazSO^ After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0 ~ 40% EtOAc in petroleum ether to afford tert-butyl ((lS*,2S*,4R)-5-((tert- butyldimethylsilyl)oxy)-l-(6-(difluoromethoxy)-2-(hydroxymethyl)pyridin-3-yl)-2-hydroxy- 4-methoxypentyl)carbamate (1.10 g, 48%) as a colorless oil. MS ESI calculated for (C24H42F₂N2O₇Si) [M+H]⁺, 537.27; found: 537.35.

Step-4:

[1672] To a stirred solution of tert-butyl ((lS*,2S*,4R)-5-((tert-butyldimethylsilyl)oxy)-l- (6-(difluoromethoxy)-2-(hydroxymethyl)pyridin-3-yl)-2-hydroxy-4- methoxypentyl)carbamate (1.0 g, 1.86 mmol) in toluene (15 mL) was added CMBP (899 mg, 3.72 mmol) at 25 °C. The resulting solution was stirred at 100 °C for 16 h. The resulting mixture was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-10% EtOAc in petroleum ether to afford tert-butyl ((5S*,6S*)-6-((R)-3-((tert-butyldimethylsilyl)oxy)-2-methoxypropyl)-2-(difluoromethoxy)- 5,8-dihydro-6H-pyrano[3,4-b]pyridin-5-yl)carbamate (420 mg, 48%) as a yellow oil. MS ESI calculated for C24H4oF2N2C>6Si [M+H]⁺, 519.26; found: 519.25.

Step-5:

[1673] To a stirred solution of tert-butyl ((5S*,6S*)-6-((R)-3-((tert- butyldimethylsilyl)oxy)-2-methoxypropyl)-2-(difluoromethoxy)-5,8-dihydro-6H-pyrano[3,4- b]pyridin-5-yl)carbamate (420 mg, 0.81 mmol) in THF (5 mL) was added TBAF (423 mg, 1.62 mmol) at 25 °C. The resulting mixture was stirred at room temperature for 1 h. The reaction was quenched with water and extracted with EtOAc. The combined organic layers were dried over anhydrous Na2SC>4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-50% EtOAc in petroleum ether to afford tert-butyl ((5S*,6S*)-2-(difhioromethoxy)-6-((R)- 3-hydroxy-2-methoxypropyl)-5,8-dihydro-6H-pyrano[3,4-b]pyridin-5-yl)carbamate (220 mg, 89%) as a yellow solid. MS ESI calculated for C18H26F2N2O6 [M+H]⁺, 405.18; found:405.15.

Step-6:

[1674] To a stirred solution of tert-butyl ((5S*,6S*)-2-(difhioromethoxy)-6-((R)-3- hydroxy-2-methoxypropyl)-5,8-dihydro-6H-pyrano[3,4-b]pyridin-5-yl)carbamate (220 mg, 0.54 mmol) in toluene (3 mL) was added 2-(tributyl-X⁵-phosphaneylidene)acetonitrile (CAS No. 157141-27-0) (197 mg, 0.82 mmol) at 25 °C. The resulting solution was stirred at 100 °C for 16 h. The resulting mixture was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-10% EtOAc in petroleum ether to afford tert-butyl (3R,4aS*,10bS*)-8-(difluoromethoxy)-3-methoxy-2,3,4,4a,6,10b- hexahydro-lH-pyrano[3,2-b:5,4-b']dipyridine-l-carboxylate (140 mg, 76%) as a yellow oil. MS ESI calculated for C18H24F2N2O5 [M+H]⁺, 387.17; found: 387.20.

Step-7: [1675] A mixture of tert-butyl (3R,4aS*,10bS*)-8-(difluoromethoxy)-3-methoxy- 2,3,4,4a,6,10b-hexahydro-lH-pyrano[3,2-b:5,4-b']dipyridine-l-carboxylate (130 mg, 0.34 mmol) and hydrogen chloride (4.0 M in ethyl acetate) (2 mL) was stirred at room temperature for 1 h. The resulting mixture was concentrated under vacuum to afford (3R,4aS*,10bS*)-8-(difluoromethoxy)-3-methoxy-2,3,4,4a,6,10b-hexahydro-lH-pyrano[3,2- b:5,4-b']dipyridine hydrochloride (A108) (120 mg, crude) as a yellow solid. MS ESI calculated for C13H16F2N2O3 [M+H]⁺, 287.11; found, 287.15. 'H NMR (300 MHz, DMSO) 5 10.13 (br, 1H), 8.81 (br, 1H), 8.23 (d, 7 = 8.4 Hz, 1H), 7.69 (t, J = 72.6 Hz, 1H), 7.10 (d, J = 8.4 Hz, 1H), 4.69 (s, 2H), 4.40 - 4.39 (m, 1H), 4.06 - 4.05 (m, 1H), 3.69 - 3.68 (m, 1H), 3.39 - 3.16 (m, 5H), 2.36 (d, J - 15.6 Hz, 1H), 2.17 - 1.86 (m, 1H). Absolute stereochemistry at two “orl” centers was not determined.

Intermediate A109: (4aS,6R, 10bS)-6-methyl-2,3,4,4a,6, 1 Ob-hexahydro- 1 H-pyrano[3,2- b:5,4-b']dipyridine-8-carbonitrile

A109

Step-1:

[1676] To a stirred solution of tert-butyl (4aS,6R,10bS)-8-chloro-6-methyl-2,3,4,4a,6,10b- hexahydro-lH-pyrano[3,2-b:5,4-b']dipyridine-l-carboxylate (from A78) (150 mg, 0.44 mmol) and Zn(CN)2 (155 mg, 1.32 mmol) in THF (1 mL) and H2O (1 mL)were added t- BuXPhos Pd G3 (52 mg, 0.06 mmol) at 25°C under nitrogen atmosphere. The resulting mixture was stirred at 50 °C for 2 h. The resulting mixture was concentrated under reduced pressure. The residue was purified by normal phase flash column chromatography which applied to 25 g silica gel column eluted with 0-55% ethyl acetate in petroleum ether to afford tert-butyl (4aS,6R,10bS)-8-cyano-6-methyl-2,3,4,4a,6,10b-hexahydro-lH-pyrano[3,2-b:5,4- b']dipyridine-l -carboxylate (120 mg, 82% yield) as a white solid. MS ESI calculated for C18H23N3O3 [M+H]⁺, 330.17; found, 330.15.

Step-2:

[1677] To a solution of tert-butyl (4aS,6R,10bS)-8-cyano-6-methyl-2,3,4,4a,6,10b- hexahydro-lH-pyrano[3,2-b:5,4-b']dipyridine-l-carboxylate (120 mg, 0.36 mmol) in 1,4- dioxane (2 mL) was added HC1 (4.0 M in 1,4-dioxane) (2 mL) at 25 °C under nitrogen atmosphere. The resulting mixture was stirred at 25°C for 1 h. The resulting mixture was concentrated under vacuum to afford (4aS,6R,10bS)-6-methyl-2,3,4,4a,6,10b-hexahydro-lH- pyrano[3,2-b:5,4-b']dipyridine-8-carbonitrile hydrochloride (A109) (crude, 100 mg) as a white solid. MS ESI calculated for C13H15N3O [M+H]⁺, 230.12; found, 230.15. 'H NMR (300 MHz, DMSC 5) 8 10.20 (s, 1H), 8.74 (br, 1H), 8.29 (d, J= 8.1 Hz, 1H), 8.09 (d, J = 8.1 Hz, 1H), 4.92 (q, J= 6.6 Hz, 1H), 4.53 - 4.52 (m, 1H), 4.14 - 4.13 (m, 1H), 3.17 - 3.07 (m, 2H), 1.87 - 1.82 (m, 2H), 1.62 (d, J = 6.6 Hz, 3H), 1.29 - 1.07 (m, 2H).

Intermediate A110 isomer 1: (2R,4aR,9bS)-7-(difluoromethoxy)-2-methyl-l,2,3,4a,5,9b- hexahydropyrido[3',2':3,4]cyclopenta[l,2-b][l,4]oxazine

A110 isomer 1 _an(j

Intermediate A110 isomer 2: (2R,4aS,9bR)-7-(difluoromethoxy)-2-methyl-l,2,3,4a,5,9b- hexahydropyrido[3',2':3,4]cyclopenta[l,2-b][l,4]oxazine

Step-1:

[1678] A mixture of 2-(difluoromethoxy)-6,7-dihydro-5H-cyclopenta[b]pyridin-5-one (6.20 g, 31.13 mmol) and CuBr2 (10.43 g, 46.69 mmol) in EtOAc (120 mL) was stirred at 80 °C for 3 h. The mixture was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with PE I EtOAc (5 : 1 ) to afford a 1 : 1 mixture of (R)-6-bromo-2-(difluoromethoxy)-6,7-dihydro-5H-cyclopenta[b]pyridin-5-one and (S)-6-bromo-2-(difluoromethoxy)-6,7-dihydro-5H-cyclopenta[b]pyridin-5-one (5.00 g, 57%) as a white solid. MS ESI calculated for C9H₆BrF₂NO2 [M+H]⁺, 277.95, 279.95; found, 278.00, 280.00.

Step-2:

[1679] To a stirred solution of 1:1 mixture of (R)-6-bromo-2-(difluoromethoxy)-6,7- dihydro-5H-cyclopenta[b]pyridin-5-one and (S)-6-bromo-2-(difluoromethoxy)-6,7-dihydro- 5H-cyclopenta[b]pyridin-5-one (5.00 g, 17.98 mmol) in MeOH (50 mL) was added NaBtL (1.36 g, 35.96 mmol) in portions at 0 °C. The resulting mixture was stirred at 25 °C for 4 h. The reaction was quenched with water at 0 °C. The resulting mixture was extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous NazSC . After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with PE / EtOAc (1:1) to afford a 1:1 mixture of (5S,6R)-6-bromo-2-(difluoromethoxy)-6,7-dihydro-5H-cyclopenta[b]pyridin-5-ol and (5R,6S)-6-bromo-2-(difluoromethoxy)-6,7-dihydro-5H-cyclopenta[b]pyridin-5-ol (4.40 g, 87%) as a white solid. MS ESI calculated for C9H₈BrF₂NO2 [M+H] ⁺, 279.97, 281.97; found, 280.00, 282.00.

Step-3:

[1680] To a stirred a 1:1 mixture of (5S,6R)-6-bromo-2-(difluoromethoxy)-6,7-dihydro- 5H-cyclopenta[b]pyridin-5-ol and (5R,6S)-6-bromo-2-(difluoromethoxy)-6,7-dihydro-5H- cyclopenta[b]pyridin-5-ol (3.30 g, 11.78 mmol) in MeCN (40 mL) was added H2SO4 (1.73 g, 17.67 mmol) dropwise at 0 °C. The resulting mixture was stirred at 70 °C for 3 h. The reaction mixture was diluted by H2O (40 mL) and the resulting mixture was stirred at 70 °C for 16 h. The resulting mixture was basified to with NaOH (aq., 30%) to pH 11-12. The mixture was extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SO4. After filtration, the filtrate was concentrated under reduced pressure to afford a 1:1 mixture of (5S,6R)-5-amino-2-(difhioromethoxy)-6,7-dihydro-5H- cyclopenta[b]pyridin-6-ol and (5R,6S)-5-amino-2-(difluoromethoxy)-6,7-dihydro-5H- cyclopenta[b]pyridin-6-ol (2.20 g, crude) as a brown solid. MS ESI calculated for C9H10F2N2O2 [M+H]⁺, 217.07; found, 217.20.

Step-4:

[1681] To a stirred a 1:1 mixture of (5S,6R)-5-amino-2-(difhioromethoxy)-6,7-dihydro-5H- cyclopenta[b]pyridin-6-ol and (5R,6S)-5-amino-2-(difluoromethoxy)-6,7-dihydro-5H- cyclopenta[b]pyridin-6-ol (2.00 g, 9.25 mmol) in methanol (5 mL) were added EtsN (1.87 g, 18.50 mmol) and BOC2O (3.03 g, 13.87 mmol) at room temperature. The resulting mixture was stirred at 25 °C for 2 h. The mixture was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with PE / EtOAc (1:1) to afford a 1:1 mixture of tert-butyl ((5S,6R)-2-(difluoromethoxy)-6-hydroxy-6,7-dihydro-5H- cyclopenta[b]pyridin-5-yl)carbamate and tert-butyl ((5R,6S)-2-(difhioromethoxy)-6-hydroxy- 6,7-dihydro-5H-cyclopenta[b]pyridin-5-yl)carbamate (2.00 g, 68%) as an off-white solid. MS ESI calculated for Ci₄Hi8F2N₂O₄. [M+H]⁺, 317.12; found, 317.15.

Step-5:

[1682] To a stirred a 1:1 mixture of tert-butyl ((5S,6R)-2-(difluoromethoxy)-6-hydroxy- 6,7-dihydro-5H-cyclopenta[b]pyridin-5-yl)carbamate and tert-butyl ((5R,6S)-2- (difluoromethoxy)-6-hydroxy-6,7-dihydro-5H-cyclopenta[b]pyridin-5-yl)carbamate (2.00 g, 6.32 mmol) in DCM (30 mL) were sequentially added NaOH (1.78 g, 44.26 mmol), (BU₄N)HSO₄ (429 mg, 1.26 mmol) and (S)-4-methyl-l,3,2-dioxathiolane 2,2-dioxide (supplier: Suzhou spark Biotechnology Co., Ltd. CAS# 174953-30-1) (1.14 g, 8.22 mmol) at 0 °C. The resulting mixture was stirred at room temperature for 2 h. The mixture was concentrated under reduced pressure. The residue was dissolved in 2-methoxy-2- methylpropane (140 mL) and H2O (4.4 mL), then a solution of TsOH (544 mg, 3.16 mmol) in 1,4-dioxane (25.5 mL) was added. The resulting mixture was stirred at 40 °C for 16 h. The reaction was quenched with NaHCCh (aq., 20%) and extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SC>4. After filtration, the filtrate was concentrated under reduced pressure to afford a 1:1 mixture of tert-butyl ((5S,6R)-2-(difluoromethoxy)-6-((S)-2-hydroxypropoxy)-6,7-dihydro-5H- cyclopenta[b]pyridin-5-yl)carbamate and tert-butyl ((5R,6S)-2-(difluoromethoxy)-6-((S)-2- hydroxypropoxy)-6,7-dihydro-5H-cyclopenta[b]pyridin-5-yl)carbamate (2.00 g, crude) as a light brown solid. MS ESI calculated for C17H24F2N2O5. [M+H]⁺, 375.17; found, 375.25.

Step-6:

[1683] To a stirred a 1:1 mixture of tert-butyl ((5S,6R)-2-(difluoromethoxy)-6-((S)-2- hydroxypropoxy)-6,7-dihydro-5H-cyclopenta[b]pyridin-5-yl)carbamate and tert-butyl ((5R,6S)-2-(difluoromethoxy)-6-((S)-2-hydroxypropoxy)-6,7-dihydro-5H- cyclopenta[b]pyridin-5-yl)carbamate (500 mg, 1.33 mmol) in toluene (10 mL) was added 2- (tributyl-A,⁵-phosphaneylidene)acetonitrile (CAS No. 157141-27-0) (644 mg, 2.67 mmol) at room temperature. The resulting mixture was stirred at 100 °C for 16 h. The resulting mixture was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with PE / EtOAc (5:1) to afford tert-butyl (2R,4aS,9bR)-7- (difluoromethoxy)-2-methyl-2,3 ,5 ,9b-tetrahydropyrido[3 ',2': 3 ,4] cyclopenta[ 1 ,2- b][ 1,4] oxazine- l(4aH)-carboxylate (150 mg, 31%) as a light yellow oil as the first eluting peak and tert-butyl (2R,4aR,9bS)-7-(difluoromethoxy)-2-methyl-2,3,5,9b- tetrahydropyrido[3',2':3,4]cyclopenta[l,2-b][l,4]oxazine-l(4aH)-carboxylate (170 mg, 35%) as a light brown oil as the second eluting peak. MS ESI calculated for C17H22F2N2O4 [M+H]⁺, 357.15; found, 357.10.

Step-7:

[1684] To a stirred solution of tert-butyl (2R,4aR,9bS)-7-(difluoromethoxy)-2-methyl- 2,3,5 ,9b-tetrahydropyrido [3 ',2': 3,4] cyclopenta[ 1 ,2-b] [ 1 ,4]oxazine- 1 (4aH)-carboxylate (170 mg, 0.47 mmol) in DCM (2 mL) was added Zinc bromide (214 mg, 0.95 mmol) at room temperature. The resulting mixture was stirred at 40 °C for 4 h. The reaction was diluted with water at room temperature and extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SO4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with PE / EtOAc (1 :1) to afford (2R,4aR,9bS)-7-(difluoromethoxy)- 2-methyl-l,2,3,4a,5,9b-hexahydropyrido[3',2':3,4]cyclopenta[l,2-b][l,4]oxazine isomer 2 (Al 10 isomer 1) (100 mg, 81%) as a light brown oil. MS ESI calculated for C12H14F2N2O2 [M+H]⁺, 256.10; found, 257.15. 'H NMR (400 MHz, DMSO-d₆) 8 7.86 - 7.48 (m, 2H), 6.89 - 6.48 (m, 1H), 4.29 - 4.22 (m, 1H), 4.05 (t, J = 4.8 Hz, 1H), 3.53 (dd, J = 10.8, 2.8 Hz, 1H), 3.27 (dd, J= 10.8, 7.2 Hz, 1H), 3.19 (dd, 7 = 16.4, 6.4 Hz, 1H), 2.87 - 2.76 (m, 2H), 0.84 (d, J = 6.4 Hz, 3H). Absolute stereochemistry was determined by NOESY.

Step-8:

[1685] To a stirred solution of tert-butyl (2R,4aS,9bR)-7-(difluoromethoxy)-2-methyl- 2,3,5 ,9b-tetrahydropyrido [3 ',2': 3,4] cyclopenta[ 1 ,2-b] [ 1 ,4]oxazine- 1 (4aH)-carboxylate (150 mg, 0.42 mmol) in DCM (2 mL) was added ZnB (189 mg, 0.84 mmol) at room temperature. The resulting mixture was stirred at 40 °C for 4 h. The reaction was diluted with water at room temperature and extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SO4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with PE / EtOAc (1:1) to afford (2R,4aS,9bR)-7-(difluoromethoxy)-2-methyl-l,2,3,4a,5,9b- hexahydropyrido[3',2':3,4]cyclopenta[l,2-b][l,4]oxazine (Al 10 isomer 2) (80 mg, 74%) as a fight brown oil. MS ESI calculated for CI₂HI₄F₂N₂O₂ [M+H]⁺, 257.10; found, 257.15.

NMR (400 MHz, DMSO-J₆) 8 7.87 - 7.49 (m, 2H), 6.87 (d, J = 8.0, 4.0 Hz, 1H), 4.24 - 4.20 (m, 1H), 4.17 - 4.13 (m, 1H), 3.43 (dd, J = 10.8, 2.8 Hz, 1H), 3.05 (dd, J= 16.8, 4.0 Hz, 1H), 3.00 - 2.93 (m, 2H), 2.58 - 2.53 (m, 1H), 0.85 (d, J= 6.4 Hz, 3H). Absolute stereochemistry was determined by NOESY.

Intermediate Alli: rel-(4R,4aS,9bR)-7-(trifluoromethyl)-l,2,3,4,4a,9b-hexahydrofuro[2,3- b:4,5-b']dipyridin-4-ol

Step-1:

[1686] To a stirred solution of rel-(4S,4aR,9bS)-4-methoxy-7-(trifluoromethyl)- l,2,3,4,4a,9b-hexahydrofuro[2,3-b:4,5-b']dipyridine hydrochloride (200 mg, 0.64 mmol) in MeOH (2 mL) and DCM (0.2 mL) was added K2CO3 (267 mg, 1.93 mmol) at room temperature. The resulting mixture was stirred at 25 °C for 30 min. The suspension was filtered. The filtrate was collected and concentrated under vacuum.

[1687] The residue was dissolved in DCM (1 mL), Then BBrs (1.5 mL, 1.50 mmol, IM in DCM) was added at 0 °C under nitrogen atmosphere. The resulting mixture was stirred at 40 °C for 16 h. The reaction was quenched by the addition of ice water at 0 °C. The resulting mixture was concentrated under reduced pressure to afford (4S,4aR,9bS)-7-(trifhioromethyl)- l,2,3,4,4a,9b-hexahydrofuro[2,3-b:4,5-b']dipyridin-4-ol (Al li) (120 mg, crude) as a yellow oh. MS ESI calculated for C11H11F3N2O2 [M+H]⁺, 261.08; found, 261.15.

Final Compound Synthesis

Example 1: rel-((R)-4-amino-l,3,6,7,8,9-hexahydrofuro[3,4-c]quinolin-8-yl)((4aR,10bR)-8- (trifluoromethyl)-2,3,4a, 1 Ob-tetrahydrochromeno [3,4-b] [ 1 ,4] oxazin- 1 (5H)-yl)methanone, isomer 3, and

Example 2: rel-((R)-4-amino-l,3,6,7,8,9-hexahydrofuro[3,4-c]quinolin-8-yl)((4aR,10bR)-8- (trifluoromethyl)-2,3,4a, 1 Ob-tetrahydrochromeno [3,4-b] [ 1 ,4] oxazin- 1 (5H)-yl)methanone, isomer 1

Step 1: 1:1:1:1 mixture of rel-((R)-4-amino-l, 3, 6,7,8, 9-hexahydrofuro[3,4-c]quinolin-8- yl)((4aR,10bR)-8-(trifhioromethyl)-2,3,4a,10b-tetrahydrochromeno[3,4-b][l,4]oxazin-l(5H)- yl)methanone, isomer 1 and rel-((R)-4-amino-l,3,6,7,8,9-hexahydrofuro[3,4-c]quinolin-8- yl)((4aR, 10bR)-8-(trifhioromethyl)-2,3,4a, 10b-tetrahydrochromeno[3,4-b] [ 1 ,4]oxazin- 1 (5H)- yl)methanone, isomer 2 and rel-((R)-4-amino-l,3,6,7,8,9-hexahydrofuro[3,4-c]quinolin-8- yl)((4aR,10bR)-8-(trifhioromethyl)-2,3,4a,10b-tetrahydrochromeno[3,4-b][l,4]oxazin-l(5H)- yl)methanone, isomer 3 and rel-((R)-4-amino-l,3,6,7,8,9-hexahydrofuro[3,4-c]quinolin-8- yl)((4aR, 10bR)-8-(trifluoromethyl)-2,3,4a, 10b-tetrahydrochromeno[3,4-b] [ 1 ,4]oxazin- 1 (5H)- yl)methanone, isomer 4

Isomer 1 Isomer 2 Isomer 3 Isomer 4

[1688] To a mixture of intermediate CAI (135 mg, 0.57 mmol), intermediate A4 (150 mg, 0.57 mmol) and TEA (175 mg, 1.73 mmol) in DMAc (2 mL) was added BOPCI (23 mg, 0.63 mmol) at 25 °C. The mixture was stirred at 25 °C for 1 h. The mixture was quenched with water and extracted with DCM. The combined organic layers were washed with brine, dried over anhydrous Na2SO4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with DCM/MeOH (5:1) to afford 1 : 1: 1 : 1 mixture of rel-((R)-4-amino-l,3,6,7,8,9-hexahydrofuro[3,4-c]quinolin- 8-yl)((4aR,10bR)-8-(trifhioromethyl)-2,3,4a,10b-tetrahydrochromeno[3,4-b][l,4]oxazin- l(5H)-yl)methanone, isomer 1 and rel-((R)-4-amino-l,3,6,7,8,9-hexahydrofuro[3,4- c]quinolin-8-yl)((4aR, 10bR)-8-(trifhioromethyl)-2,3,4a, 10b-tetrahydrochromeno[3,4- b][ 1,4] oxazin- l(5H)-yl)methanone, isomer 2 and rel-((R)-4-amino-l,3,6,7,8,9- hexahydrofuro[3,4-c]quinolin-8-yl)((4aR, 10bR)-8-(trifluoromethyl)-2,3,4a, 10b- tetrahydrochromeno[3,4-b][l,4]oxazin-l(5H)-yl)methanone, isomer 3 and rel-((R)-4-amino- l,3,6,7,8,9-hexahydrofuro[3,4-c]quinolin-8-yl)((4aR,10bR)-8-(trifluoromethyl)-2,3,4a,10b- tetrahydrochromeno[3,4-b][l,4]oxazin-l(5H)-yl)methanone, isomer 4 (50 mg, 18%) as an off-white solid. MS ESI calculated for C24H24F3N3O4 [M+H]⁺,476.17; found, 476.15.

Step 2: rel-((R)-4-amino-l ,3,6,7,8,9-hexahydrofuro[3,4-c]quinolin-8-yl)((4aR,10bR)-8- (trifluoromethyl)-2,3,4a, 1 Ob-tetrahydrochromeno [3,4-b] [ 1 ,4] oxazin- 1 (5H)-yl)methanone, isomer 3, and rel-((R)-4-amino-l,3,6,7,8,9-hexahydrofuro[3,4-c]quinolin-8-yl)((4aR,10bR)-8- (trifhioromethyl)-2,3,4a, 1 Ob-tetrahydrochromeno [3,4-b] [ 1 ,4] oxazin- 1 (5H)-yl)methanone, isomer 1

[1689] The 1:1:1:1 mixture of rel-((R)-4-amino-l,3,6,7,8,9-hexahydrofuro[3,4-c]quinolin- 8-yl)((4aR,10bR)-8-(trifluoromethyl)-2,3,4a,10b-tetrahydrochromeno[3,4-b][l,4]oxazin- 1 (5H)-yl)methanone, isomer 1 and rel-((R)-4-amino-l,3,6,7,8,9-hexahydrofuro[3,4- c]quinolin-8-yl)((4aR, 10bR)-8-(trifluoromethyl)-2,3,4a, 10b-tetrahydrochromeno[3,4- b][ 1,4] oxazin- l(5H)-yl)methanone, isomer 2 and rel-((R)-4-amino-l,3,6,7,8,9- hexahydrofuro[3,4-c]quinolin-8-yl)((4aR,10bR)-8-(trifluoromethyl)-2,3,4a,10b- tetrahydrochromeno[3,4-b][l,4]oxazin-l(5H)-yl)methanone, isomer 3 and rel-((R)-4-amino- l,3,6,7,8,9-hexahydrofuro[3,4-c]quinolin-8-yl)((4aR,10bR)-8-(trifluoromethyl)-2,3,4a,10b- tetrahydrochromeno[3,4-b][l,4]oxazin-l(5H)-yl)methanone, isomer 4 (50 mg) was separated by prep-chiral HPLC with the following conditions: [Column: CHIRALPAK IC, 2*25 cm, 5 pm; Mobile Phase A: Hex(0.3% IPAMIN), Mobile Phase B: EtOH: DCM=1: 1-HPLC; Flow rate: 20 rnL/min; Gradient: 40% B to 40% B in 21 min; Wave Length: 220/254 nm;

RTl(min): 8.04; RT2(min): 10.29; RT3(min): 16.46; Sample Solvent: EtOH: DCM=1: 1- HPLC; Injection Volume: 0.35 mL; Number Of Runs: 6] to afford rel-((R)-4-amino- l,3,6,7,8,9-hexahydrofuro[3,4-c]quinolin-8-yl)((4aR,10bR)-8-(trifluoromethyl)-2,3,4a,10b- tetrahydrochromeno[3,4-b][l,4]oxazin-l(5H)-yl)methanone, isomer 1 (5.6 mg, 3%) as an off- white solid with retention time at 8.04 minute and rel-((R)-4-amino-l,3,6,7,8,9- hexahydrofuro[3,4-c]quinolin-8-yl)((4aR,10bR)-8-(trifluoromethyl)-2,3,4a,10b- tetrahydrochromeno[3,4-b][l,4]oxazin-l(5H)-yl)methanone, isomer 2 (4.0 mg, 2%) as an off- white solid with retention time at 10.2 minute. The chiral resolution also afforded a mixture A (14 mg) with retention time at 16.46 minute.

[1690] The mixture A (14 mg) was separated by prep-chiral HPLC with the following conditions: [Column: CHIRAL ART Cellulose-SB, 2*25 cm, 5 pm; Mobile Phase A: Hex(0.2% IPAMine)— HPLC, Mobile Phase B: EtOH: DCM=1: 1-HPLC; Flow rate: 20 mL/min; Gradient: 40% B to 40% B in 20 min; Wave Length: 220/254 nm; RTl(min): 9.1; RT2(min): 16.59; Sample Solvent: EtOH: DCM=1: 1— HPLC; Injection Volume: 0.9 mL; Number Of Runs: 2] to afford rel-((R)-4-amino-l,3,6,7,8,9-hexahydrofuro[3,4-c]quinolin-8- yl)((4aR,10bR)-8-(trifluoromethyl)-2,3,4a,10b-tetrahydrochromeno[3,4-b][l,4]oxazin-l(5H)- yl)methanone, isomer 3 (3.9 mg, 28%) with retention time at 9.1 minute and rel-((R)-4- amino-l,3,6,7,8,9-hexahydrofuro[3,4-c]quinolin-8-yl)((4aR,10bR)-8-(trifluoromethyl)- 2,3,4a,10b-tetrahydrochromeno[3,4-b][l,4]oxazin-l(5H)-yl)methanone, isomer 4 (3.3 mg, 23%) with retention time at 16.59 minute.

[1691] rel-((R)-4-amino-l,3,6,7,8,9-hexahydrofuro[3,4-c]quinolin-8-yl)((4aR,10bR)-8- (trifluoromethyl)-2,3,4a, 1 Ob-tetrahydrochromeno [3,4-b] [ 1 ,4] oxazin- 1 (5H)-yl)methanone, isomer 1: MS (ESI) calculated for C24H24F3N3O4 [M+H]⁺, 476.17; found, 476.25. ¹H NMR (400 MHz, DMSO-de) 57.37 - 7.23 (m, 1H), 7.20 - 6.95 (m, 2H), 5.89 - 5.51 (m, 3H), 5.06

- 4.72 (m, 4H), 4.55 - 4.11 (m, 2H), 4.04 - 3.89 (m, 1H), 3.86 - 3.72 (m, 2H), 3.69 - 3.49 (m, 1H), 3.20 - 2.99 (m, 1H), 2.93 - 2.55 (m, 4H), 2.48 - 2.25 (m, 1H), 2.13 - 1.71 (m, 2H).

[1692] rel-((R)-4-amino-l,3,6,7,8,9-hexahydrofuro[3,4-c]quinolin-8-yl)((4aR,10bR)-8- (trifluoromethyl)-2,3,4a, 1 Ob-tetrahydrochromeno [3,4-b] [ 1 ,4] oxazin- 1 (5H)-yl)methanone, isomer 2: MS (ESI) calculated for C24H24F3N3O4 [M+H]⁺, 476.17; found, 476.25. NMR (400 MHz, DMSC >) 5 7.35 - 7.22 (m, 1H), 7.16 - 6.99 (m, 2H), 5.87 - 5.40 (m, 3H), 5.06

- 4.71 (m, 4H), 4.50 - 4.40 (m, 1H), 4.39 - 4.29 (m, 1H), 4.24 - 3.76 (m, 3H), 3.70 - 3.46 (m, 1H), 3.24 - 2.99 (m, 1H), 2.97 - 2.54 (m, 4H), 2.44 - 2.32 (m, 1H), 2.11 - 1.98 (m, 1H), 1.90 - 1.70 (m, 1H).

[1693] rel-((R)-4-amino-l,3,6,7,8,9-hexahydrofuro[3,4-c]quinolin-8-yl)((4aR,10bR)-8- (trifhioromethyl)-2,3,4a, 1 Ob-tetrahydrochromeno [3,4-b] [ 1 ,4] oxazin- 1 (5H)-yl)methanone, isomer 3: MS (ESI) calculated for C24H24F3N3O4 [M+H]⁺, 476.17; found, 476.15. 'H NMR (400 MHz, DMSO- fe) 5 7.37 - 7.23 (m, 1H), 7.20 - 6.95 (m, 2H), 5.89 - 5.51 (m, 3H), 5.06

[1694] rel-((R)-4-amino-l,3,6,7,8,9-hexahydrofuro[3,4-c]quinolin-8-yl)((4aR,10bR)-8- (trifhioromethyl)-2,3,4a, 1 Ob-tetrahydrochromeno [3,4-b] [ 1 ,4] oxazin- 1 (5H)-yl)methanone, isomer 4: MS (ESI) calculated for C24H24F3N3O4 [M+H]⁺, 476.17; found, 476.15. ¹H NMR (400 MHz, DMSO-de) 57.35 - 7.22 (m, 1H), 7.16 - 6.99 (m, 2H), 5.87 - 5.40 (m, 3H), 5.06

- 4.71 (m, 4H), 4.50 - 4.40 (m, 1H), 4.39 - 4.29 (m, 1H), 4.24 - 3.76 (m, 3H), 3.70 - 3.46 (m, 1H), 3.24 - 2.99 (m, 1H), 2.97 - 2.54 (m, 4H), 2.44 - 2.32 (m, 1H), 2.11 - 1.98 (m, 1H), 1.90 - 1.70 (m, 1H). Example 3: rel-((R)-4-amino-l,3,6,7,8,9-hexahydrofuro[3,4-c]quinolin-8-yl)((4aR,9bR)-7- (trifluoromethyl)-3,4,4a,9b-tetrahydrobenzofuro[3,2-b]pyridin-l(2H)-yl)methanone, isomer 3

Step 1: 1:1:1:1 mixture of rel-((R)-4-amino-l,3,6,7,8,9-hexahydrofuro[3,4-c]quinolin-8- yl)((4aR,9bR)-7-(trifhioromethyl)-3,4,4a,9b-tetrahydrobenzofuro[3,2-b]pyridin-l(2H)- yl)methanone, isomer 1 and rel-((R)-4-amino-l,3,6,7,8,9-hexahydrofuro[3,4-c]quinolin-8- yl)((4aR,9bR)-7-(trifluoromethyl)-3,4,4a,9b-tetrahydrobenzofuro[3,2-b]pyridin-l(2H)- yl)methanone, isomer 2 and rel-((R)-4-amino-l,3,6,7,8,9-hexahydrofuro[3,4-c]quinolin-8- yl)((4aR,9bR)-7-(trifhioromethyl)-3,4,4a,9b-tetrahydrobenzofuro[3,2-b]pyridin-l(2H)- yl)methanone, isomer 3 and rel-((R)-4-amino-l,3,6,7,8,9-hexahydrofuro[3,4-c]quinolin-8- yl)((4aR,9bR)-7-(trifhioromethyl)-3,4,4a,9b-tetrahydrobenzofuro[3,2-b]pyridin-l(2H)- yl)methanone, isomer 4

[1695] To a stirred solution of intermediate A10 (70 mg, 0.28 mmol) and intermediate CA3 (67 mg, 0.28 mmol) in DMAC (1 mL) were added bis(2-oxo-l,3-oxazolidin-3- yl)phosphinoyl chloride (109 mg, 0.43 mmol) and TEA (87 mg, 0.86 mmol) at 0 °C. The resulting mixture was stirred at room temperature for 1 h. The reaction mixture was quenched by the addition of water and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under vacuum. The residue was dissolved in DMF (2 mL) and was purified by prep-HPLC with the following conditions: [Column: XSelect CSH Prep C18 OBD Column, 19*250 mm, 5 pm; Mobile Phase A: Water (lOmmol/L NH4HCO3), Mobile Phase B: ACN; Flow rate: 20 mL/min; Gradient: 50% B to 60% B in 10 min; Wave Length: 254/220 nm] to afford 1:1:1: 1 mixture of rel-((R)-4-amino-l,3,6,7,8,9-hexahydrofuro[3,4-c]quinolin-8-yl)((4aR,9bR)-7- (trifluoromethyl)-3,4,4a,9b-tetrahydrobenzofuro[3,2-b]pyridin-l(2H)-yl)methanone, isomer 1 and rel-((R)-4-amino-l,3,6,7,8,9-hexahydrofuro[3,4-c]quinohn-8-yl)((4aR,9bR)-7- (trifluoromethyl)-3,4,4a,9b-tetrahydrobenzofuro[3,2-b]pyridin-l(2H)-yl)methanone, isomer 2 and rel-((R)-4-amino-l,3,6,7,8,9-hexahydrofuro[3,4-c]quinohn-8-yl)((4aR,9bR)-7- (trifluoromethyl)-3,4,4a,9b-tetrahydrobenzofuro[3,2-b]pyridin-l(2H)-yl)methanone, isomer 3 and rel-((R)-4-amino-l,3,6,7,8,9-hexahydrofuro[3,4-c]quinohn-8-yl)((4aR,9bR)-7- (trifluoromethyl)-3,4,4a,9b-tetrahydrobenzofuro[3,2-b]pyridin-l(2H)-yl)methanone, isomer 4 (50 mg, 37%) as an off-white solid. MS ESI calculated for C24H24F3N3O3 [M+H]⁺, 460.18; found, 460.20. 'H NMR (400 MHz, DMSO-d₆) 57.46 - 7.16 (m, 3H), 6.27 - 6.02 (m, 1H), 5.86 - 5.57 (m, 2H), 5.21 - 5.02 (m, 1H), 4.99 - 4.73 (m, 4H), 4.19 - 3.84 (m, 1H), 3.22 - 3.01 (m, 1H), 2.94 - 2.57 (m, 4H), 2.46 - 2.31 (m, 1H), 2.10 - 1.64 (m, 5H), 1.64 - 1.48 (m, 1H).

Step 2: rel-((R)-4-amino- 1 ,3,6,7,8,9-hexahydrofuro[3,4-c]quinolin-8-yl)((4aR,9bR)-7- (trifhioromethyl)-3,4,4a,9b-tetrahydrobenzofuro[3,2-b]pyridin-l(2H)-yl)methanone, isomer 3

[1696] The 1:1:1:1 mixture ofrel-((R)-4-amino-l,3,6,7,8,9-hexahydrofuro[3,4-c]quinolin- 8-yl)((4aR,9bR)-7-(trifhioromethyl)-3,4,4a,9b-tetrahydrobenzofuro[3,2-b]pyridin-l(2H)- yl)methanone, isomer 1 and rel-((R)-4-amino-l,3,6,7,8,9-hexahydrofuro[3,4-c]quinolin-8- yl)((4aR,9bR)-7-(trifhioromethyl)-3,4,4a,9b-tetrahydrobenzofuro[3,2-b]pyridin-l(2H)- yl)methanone, isomer 2 and rel-((R)-4-amino-l,3,6,7,8,9-hexahydrofuro[3,4-c]quinolin-8- yl)((4aR,9bR)-7-(trifhioromethyl)-3,4,4a,9b-tetrahydrobenzofuro[3,2-b]pyridin-l(2H)- yl)methanone, isomer 3 and rel-((R)-4-amino-l,3,6,7,8,9-hexahydrofuro[3,4-c]quinolin-8- yl)((4aR,9bR)-7-(trifhioromethyl)-3,4,4a,9b-tetrahydrobenzofuro[3,2-b]pyridin-l(2H)- yl)methanone, isomer 4 (50 mg, 0.10 mmol) was separated by prep-Chiral-HPLC with the following conditions; [Column: CHIRAL ART Cellulose-SC, 2*25 cm, 5 pm; Mobile Phase A: Hex (0.2% IPAMine)-HPLC, Mobile Phase B: EtOH: DCM=1: 1-HPLC; Flow rate: 20 mL/min; Gradient: 50% B to 50% B in 11.5 min; Wave Length: 220/254 nm; RT1 (min): 5.68; RT2 (min): 7.71; RT3 (min): 10.15; Sample Solvent: EtOH: DCM=1: L-HPLC; Injection Volume: 0.85 mL; Number of Runs: 3] to afford Fraction A (isomer 1 and isomer 2) as a white solid with the first peak on chiral HPLC with retention time at 5.68 minute and rel-((R)-4-amino-l,3,6,7,8,9-hexahydrofuro[3,4-c]quinolin-8-yl)((4aR,9bR)-7- (trifluoromethyl)-3,4,4a,9b-tetrahydrobenzofuro[3,2-b]pyridin-l(2H)-yl)methanone, isomer 3 (3.8 mg, 7%) as a white solid with the second peak on chiral HPLC with retention time at 7.71 minute and rel-((R)-4-amino-l,3,6,7,8,9-hexahydrofuro[3,4-c]quinolin-8-yl)((4aR,9bR)- 7 -(trifluoromethyl)-3 ,4,4a,9b-tetrahydrobenzofuro [3 ,2-b]pyridin- 1 (2H)-yl)methanone, isomer 4 (6.3 mg, 12%) as a white solid with the third peak on chiral HPLC with retention time at 10.15 minute.

[1697] The racemic product Fraction A was further separated by prep-chiral HPLC with the following conditions Column: [Column: CHIRALPAK IF, 2*25 cm, 5 pm; Mobile Phase A: Hex(0.3% IPAMIN), Mobile Phase B: EtOH: DCM=1: 1-HPLC; Flow rate: 20 mL/min;

Gradient: 30% B to 30% B in 21 min; Wave Length: 220/254 nm; RTl(min): 13.52; RT2(min): 17.85; Sample Solvent: EtOH: DCM=1: 1— HPLC; Injection Volume: 0.4 mL; Number Of Runs: 4] to afford rel-((R)-4-amino-l,3,6,7,8,9-hexahydrofuro[3,4-c]quinolin-8- yl)((4aR,9bR)-7-(trifhioromethyl)-3,4,4a,9b-tetrahydrobenzofuro[3,2-b]pyridin-l(2H)- yl)methanone, isomer 1 (3.9 mg, 7.29%) as a white solid with the first peak on chiral HPLC with retention time at 13.52 minute and rel-((R)-4-amino-l,3,6,7,8,9-hexahydrofuro[3,4- c]quinolin-8-yl)((4aR,9bR)-7-(trifluoromethyl)-3,4,4a,9b-tetrahydrobenzofuro[3,2-b]pyridin- l(2H)-yl)methanone, isomer 2 (7.1 mg, 13.93%) as a white solid with the second peak on chiral HPLC with retention time at 17.85 minute.

[1698] rel-((R)-4-amino-l ,3,6,7,8,9-hexahydrofuro[3,4-c]quinolin-8-yl)((4aR,9bR)-7- (trifhioromethyl)-3,4,4a,9b-tetrahydrobenzofuro[3,2-b]pyridin-l(2H)-yl)methanone, isomer 1: MS (ESI) calc’d for (C24H24F3N3O3) [M+H]⁺, 460.18; found, 460.20. 'H NMR (400 MHz, DMSO-d₆) 6 7.45 - 7.16 (m, 3H), 6.27 - 6.04 (m, 1H), 5.68 (s, 2H), 5.17 - 5.07 (m, 1H), 4.97 - 4.76 (m, 4H), 4.27 - 3.76 (m, 1H), 3.08 - 3.01 (m, 1H), 2.95 - 2.85 (m, 1H), 2.77 - 2.61 (m, 3H), 2.48 - 2.35 (m, 1H), 2.01 - 1.95 (m, 1H), 1.92 - 1.67 (m, 4H), 1.63 - 1.48 (m, 1H).

[1699] rel-((R)-4-amino-l,3,6,7,8,9-hexahydrofuro[3,4-c]quinolin-8-yl)((4aR,9bR)-7- (trifhioromethyl)-3,4,4a,9b-tetrahydrobenzofuro[3,2-b]pyridin-l(2H)-yl)methanone, isomer 2: MS (ESI) calc’d for (C24H24F3N3O3) [M+H]⁺, 460.18; found, 460.20. ’H NMR (400 MHz, DMSO-Je) 8 7.45 - 7.14 (m, 3H), 6.28 - 6.08 (m, 1H), 5.68 (s, 2H), 5.22 - 5.07 (m, 1H), 4.97 - 4.78 (m, 4H), 4.24 - 3.83 (m, 1H), 3.21 - 3.02 (m, 1H), 2.96 - 2.81 (m, 1H), 2.77

- 2.58 (m, 3H), 2.40 - 2.29 (m, 1H), 2.07 - 1.99 (m, 1H), 1.94 - 1.80 (m, 2H), 1.77 - 1.66 (m, 2H), 1.62 - 1.50 (m, 1H).

[1700] rel-((R)-4-amino-l ,3,6,7,8,9-hexahydrofuro[3,4-c]quinolin-8-yl)((4aR,9bR)-7- (trifluoromethyl)-3,4,4a,9b-tetrahydrobenzofuro[3,2-b]pyridin-l(2H)-yl)methanone, isomer 3: MS (ESI) calc’d for (C24H24F3N3O3) [M+H]⁺, 460.18; found, 460.20. ’H NMR (400 MHz, DMSG ?) 6 7.45 - 7.16 (m, 3H), 6.28 - 6.06 (m, 1H), 5.72 (s, 2H), 5.18 - 5.03 (m, 1H), 4.99 - 4.61 (m, 4H), 4.23 - 3.80 (m, 1H), 3.06 - 3.04 (m, 1H), 2.96 - 2.81 (m, 1H), 2.77 - 2.58 (m, 3H), 2.48 - 2.31 (m, 1H), 2.07 - 1.99 (m, 1H), 1.94 - 1.80 (m, 4H), 1.64 - 1.39 (m, 1H).

[1701] rel-((R)-4-amino-l,3,6,7,8,9-hexahydrofuro[3,4-c]quinolin-8-yl)((4aR,9bR)-7- (trifluoromethyl)-3,4,4a,9b-tetrahydrobenzofuro[3,2-b]pyridin-l(2H)-yl)methanone, isomer 4: MS (ESI) calc’d for (C24H24F3N3O3) [M+H]⁺, 460.18; found, 460.20 'H NMR (400 MHz, DMSO-d₆) 57.46 - 7.13 (m, 3H), 6.23 - 6.02 (m, 1H), 5.74 (s, 2H), 5.23 - 5.06 (m, 1H), 5.02 - 4.64 (m, 4H), 4.23 - 3.83 (m, 1H), 3.06 - 3.04 (m, 1H), 2.94 - 2.79 (m, 1H), 2.78 - 2.54 (m, 3H), 2.48 - 2.33 (m, 1H), 2.08 - 1.90 (m, 1H), 1.90 - 1.78 (m, 2H), 1.77 - 1.45 (m, 3H).

Example 4: 1:1 mixture of ((R)-2-amino-6,7,8,9-tetrahydro-5H-cyclohepta[b]pyridin-6- yl)((2R* ,4aS * , 10bR*)-2-methyl-8-(trifluoromethyl)-3 ,4,4a, 10b-tetrahydro-2H-chromeno [4,3- b]pyridin-l(5H)-yl)methanone and ((S)-2-amino-6,7,8,9-tetrahydro-5H-cyclohepta[b]pyridin- 6-yl)((2R* ,4aS* , 10bR*)-2-methyl-8-(trifluoromethyl)-3 ,4,4a, 10b-tetrahydro-2H- chromeno[4,3-b]pyridin- 1 (5H)-yl)methanone

Step 1 : 1 :1 mixture of ((R)-2-(tert-butylamino)-6,7,8,9-tetrahydro-5H-cyclohepta[b]pyridin-

6-yl)((2R* ,4aS* , 10bR*)-2-methyl-8-(trifluoromethyl)-3 ,4,4a, 10b-tetrahydro-2H- chromeno[4,3-b]pyridin- 1 (5H)-yl)methanone and ((S)-2-(tert-butylamino)-6,7,8,9-tetrahydro- 5H-cyclohepta[b]pyridin-6-yl)((2R*,4aS*,10bR*)-2-methyl-8-(trifluoromethyl)-3,4,4a,10b- tetrahydro-2H-chromeno[4,3-b]pyridin-l(5H)-yl)methanone

[1702] To a stirred solution of CA2 (50 mg, 0.19 mmol) and DMF (1 drop) in DCM (1 mL) was added oxalic dichloride (49 mg, 0.38 mmol) dropwise at 0 °C. The resulting mixture was stirred at room temperature for 0.5 h. To the above mixture were added intermediate A6 isomer 1 (51 mg, 0.19 mmol) and TEA (58 mg, 0.57 mmol) at room temperature. The resulting mixture was stirred at room temperature for another 1 h. The resulting mixture was concentrated under reduced pressure. The residue was purified by reverse phase flash column chromatography with 5% ~ 80% MeCN in water (10 mmol/L NH4HCO3) to afford 1 :1 mixture of ((R)-2-(tert-butylamino)-6,7,8,9-tetrahydro-5H-cyclohepta[b]pyridin-6- yl)((2R* ,4aS * , 10bR*)-2-methyl-8-(trifluoromethyl)-3 ,4,4a, 10b-tetrahydro-2H-chromeno [4,3- b]pyridin- 1 (5H)-yl)methanone and ((S)-2-(tert-butylamino)-6,7,8,9-tetrahydro-5H- cyclohepta[b]pyridin-6-yl)((2R*,4aS *, 10bR*)-2-methyl-8-(trifluoromethyl)-3,4,4a, 10b- tetrahydro-2H-chromeno[4,3-b]pyridin-l(5H)-yl)methanone (15 mg, 9%) as a yellow solid. MS ESI calculated for C29H36F3N3O2 [M+H]⁺, 516.28; found, 516.25.

Step 2: 1:1 mixture of ((R)-2-amino-6,7,8,9-tetrahydro-5H-cyclohepta[b]pyridin-6- yl)((2R* ,4aS * , 10bR*)-2-methyl-8-(trifhioromethyl)-3 ,4,4a, 10b-tetrahydro-2H-chromeno [4,3- b]pyridin- 1 (5H)-yl)methanone and ((S)-2-amino-6,7,8,9-tetrahydro-5H-cyclohepta[b]pyridin-

6-yl)((2R* ,4aS* , 10bR*)-2-methyl-8-(trifluoromethyl)-3 ,4,4a, 10b-tetrahydro-2H- chromeno[4,3-b]pyridin- 1 (5H)-yl)methanone [1703] A 1:1 mixture of ((R)-2-(tert-butylamino)-6,7,8,9-tetrahydro-5H- cyclohepta[b]pyridin-6-yl)((2S,4aR,10bS)-2-methyl-8-(trifluoromethyl)-3,4,4a,10b- tetrahydro-2H-chromeno[4,3-b]pyridin-l(5H)-yl)methanone, isomer 1 and ((R)-2-(tert- butylamino)-6,7,8,9-tetrahydro-5H-cyclohepta[b]pyridin-6-yl)((2S,4aR,10bS)-2-methyl-8- (trifluoromethyl)-3,4,4a,10b-tetrahydro-2H-chromeno[4,3-b]pyridin-l(5H)-yl)methanone, isomer 2 (13 mg, 0.03 mmol) in TFA (2 mL) was stirred at 70 °C for 1 h. The resulting mixture was concentrated under reduced pressure. The residue was basified to pH 8 with saturated sodium bicarbonate aqueous solution and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered and concentrated under vacuum. The crude product was purified by Prep-HPLC with the following conditions [Column: Xselect CSH C18 OBD Column 30* 150mm 5pm;

Mobile Phase A: Water (0.1% FA), Mobile Phase B: ACN; Flow rate: 60 mL/min; Gradient: 5% B to 5% B in 2 min, 15% B to 35% B in 15 min; Wave Length: 254/220 nm; RTl(min): 13.5] to afford 1:1 mixture of ((R)-2-amino-6,7,8,9-tetrahydro-5H-cyclohepta[b]pyridin-6- yl)((2R* ,4aS * , 10bR*)-2-methyl-8-(trifhioromethyl)-3 ,4,4a, 10b-tetrahydro-2H-chromeno [4,3- b]pyridin-l(5H)-yl)methanone and ((S)-2-amino-6,7,8,9-tetrahydro-5H-cyclohepta[b]pyridin- 6-yl)((2R* ,4aS* , 10bR*)-2-methyl-8-(trifluoromethyl)-3 ,4,4a, 10b-tetrahydro-2H- chromeno[4,3-b]pyridin-l(5H)-yl)methanone (1.3 mg, 11%) as a white solid. MS ESI calculated for C25H28F3N3O2 [M+H]⁺, 460.21; found, 460.15. 'H NMR (400 MHz, Methanoldi 6 7.47 - 7.34 (m, 1H), 7.29 - 7.11 (m, 2H), 7.10 - 7.04 (m, 1H), 6.54 - 6.38 (m, 1H), 6.16 - 5.31 (m, 1H), 4.40 - 4.24 (m, 3H), 3.25 - 3.12 (m, 1H), 3.11 - 2.93 (m, 1H), 2.92 - 2.65 (m, 3H), 2.28 - 2.06 (m, 3H), 2.05 - 1.81 (m, 3H), 1.80 - 1.46 (m, 3H), 0.87 - 0.68 (m, 3H).

Example 5: rel-((R)-4-amino-l,3,6,7,8,9-hexahydrofuro[3,4-c]quinolin-8-yl)((4aR,9aS)-7- (difhioromethoxy)-2,3 ,9,9a-tetrahydroindeno [2, 1 -b] [ 1 ,4] oxazin-4(4aH)-yl)methanone, isomer 4

Step 1: 1:1:1:1 mixture of rel-((R)-4-amino-l, 3, 6,7,8, 9-hexahydrofuro[3,4-c]quinolin-8- yl)((4aR,9aS)-7-(difluoromethoxy)-2,3,9,9a-tetrahydroindeno[2, 1 -b] [1 ,4]oxazin-4(4aH)- yl)methanone, isomer 1 and rel-((R)-4-amino-l,3,6,7,8,9-hexahydrofuro[3,4-c]quinolin-8- yl)((4aR,9aS)-7-(difluoromethoxy)-2,3,9,9a-tetrahydroindeno[2,l-b][l,4]oxazin-4(4aH)- yl)methanone, isomer 2 and rel-((R)-4-amino-l,3,6,7,8,9-hexahydrofuro[3,4-c]quinolin-8- yl)((4aR,9aS)-7-(difluoromethoxy)-2,3,9,9a-tetrahydroindeno[2,l-b][l,4]oxazin-4(4aH)- yl)methanone, isomer 3 and rel-((R)-4-amino-l,3,6,7,8,9-hexahydrofuro[3,4-c]quinolin-8- yl)((4aR,9aS)-7-(difluoromethoxy)-2,3,9,9a-tetrahydroindeno[2,l-b][l,4]oxazin-4(4aH)- yl)methanone, isomer 4

[1704] To a stirred solution/mixture of intermediate A13 (150 mg, 0.52mmol) and TEA (315 mg, 3.13 mmol) in DMF (2 mL) were added TBTU (299 mg, 0.93 mmol) and intermediate CAI (145 mg, 0.62 mmol). The mixture was stirred at 25 °C for 16 h. The reaction mixture was purified by reverse phase flash column chromatography with 5-70% MeCN in water (0.1% fromic acid) to afford 1:1: 1:1 mixture of rel-((R)-4-amino-l,3,6,7,8,9- hexahydrofuro[3,4-c]quinolin-8-yl)((4aR,9aS)-7-(difluoromethoxy)-2,3,9,9a- tetrahydroindeno[2,l-b][l,4]oxazin-4(4aH)-yl)methanone, isomer 1 and rel-((R)-4-amino-

1,3, 6,7,8, 9-hexahydrofuro[3,4-c]quinolin-8-yl)((4aR,9aS)-7-(difluoromethoxy)-2, 3, 9,9a- tetrahydroindeno[2,l-b][l,4]oxazin-4(4aH)-yl)methanone, isomer 2 and rel-((R)-4-amino-

1,3, 6,7,8, 9-hexahydrofuro[3,4-c]quinolin-8-yl)((4aR,9aS)-7-(difluoromethoxy)-2, 3, 9,9a- tetrahydroindeno[2,l-b][l,4]oxazin-4(4aH)-yl)methanone, isomer 3 and rel-((R)-4-amino-

1,3, 6,7,8, 9-hexahydrofuro[3,4-c]quinolin-8-yl)((4aR,9aS)-7-(difluoromethoxy)-2, 3, 9,9a- tetrahydroindeno[2,l-b][l,4]oxazin-4(4aH)-yl)methanone, isomer 4 formate (31.9 mg, ) as a white solid. MS ESI calculated for C24H25F2N3O4 [M+H]⁺, 458.18; found, 458.25. 'H NMR (400 MHz, DMSO-d₆) 6 8.15 (s, 1H), 7.37 - 6.92 (m, 4H), 5.77 (s, 2H), 5.63 - 5.35 (m, 1H), 5.06 - 4.81 (m, 4H), 4.30 - 4.28 (m, 1H), 4.20 - 3.84 (m, 1H), 3.75 - 3.72 (m, 1H), 3.57 - 3.39 (m, 1H), 3.15 - 2.99 (m, 3H), 2.83 - 2.55 (m, 5H), 2.18 - 2.05 (m, 1H), 1.85 - 1.71 (m, 1H). Step 2: rel-((R)-4-amino-l,3,6,7,8,9-hexahydrofuro[3,4-c]quinolin-8-yl)((4aR,9aS)-7- (difluoromethoxy)-2,3 ,9,9a-tetrahydroindeno [2, 1 -b] [ 1 ,4] oxazin-4(4aH)-yl)methanone, isomer 4

[1705] The 1:1:1:1 mixture of rel-((R)-4-amino-l,3,6,7,8,9-hexahydrofuro[3,4-c]quinolin- 8-yl)((4aR,9aS)-7-(difluoromethoxy)-2,3,9,9a-tetrahydroindeno[2,l-b][l,4]oxazin-4(4aH)- yl)methanone, isomer 1 and rel-((R)-4-amino-l ,3,6,7,8,9-hexahydrofuro[3,4-c]quinolin-8- yl)((4aR,9aS)-7-(difluoromethoxy)-2,3,9,9a-tetrahydroindeno[2,l-b][l,4]oxazin-4(4aH)- yl)methanone, isomer 2 and rel-((R)-4-amino-l,3,6,7,8,9-hexahydrofuro[3,4-c]quinolin-8- yl)((4aR,9aS)-7-(difluoromethoxy)-2,3,9,9a-tetrahydroindeno[2,l-b][l,4]oxazin-4(4aH)- yl)methanone, isomer 3 and rel-((R)-4-amino-1 ,3,6,7,8,9-hexahydrofuro[3,4-c]quinolin-8- yl)((4aR,9aS)-7-(difluoromethoxy)-2,3,9,9a-tetrahydroindeno[2,l-b][l,4]oxazin-4(4aH)- yl)methanone, isomer 4 formate (30 mg) was separated by prep-chiral HPLC with the following conditions: [Column: CHIRALPAK IC, 2*25 cm, 5 pm; Mobile Phase A: Hex (0.3% IPAMIN), Mobile Phase B: EtOH: DCM=1: 1-HPLC; How rate: 20 mL/min;

Gradient: 50% B to 50% B in 19 min; Wave Length: 220/254 nm; RTl(min): 7.77;

RT2(min): 8.84; RT3(min): 12.77; RT4(min): 17.26; Sample Solvent: EtOH: DCM=1 : 1- HPLC; Injection Volume: 0.25 mL; Number Of Runs: 4] to afford rel-((R)-4-amino- 1,3, 6,7,8, 9-hexahydrofuro[3,4-c]quinolin-8-yl)((4aR,9aS)-7-(difluoromethoxy)-2, 3, 9,9a- tetrahydroindeno[2,l-b][l,4]oxazin-4(4aH)-yl)methanone, isomer 1) (2.8 mg, 10%) as a white solid with retention time at 7.77 minute and rel-((R)-4-amino-l,3,6,7,8,9- hexahydrofuro[3,4-c]quinolin-8-yl)((4aR,9aS)-7-(difluoromethoxy)-2,3,9,9a- tetrahydroindeno[2,l-b][l,4]oxazin-4(4aH)-yl)methanone, isomer 2) (2.5 mg, 9%) as a white solid with retention time at 8.84 minute.

[1706] The chiral resolution also afforded rel-((R)-4-amino-l,3,6,7,8,9-hexahydrofuro[3,4- c]quinolin-8-yl)((4aR,9aS)-7-(difluoromethoxy)-2,3,9,9a-tetrahydroindeno[2,l- b][l,4]oxazin-4(4aH)-yl)methanone, isomer 3 (3.4 mg, 12%) as a white solid with retention time at 12.77 minute and rel-((R)-4-amino-l,3,6,7,8,9-hexahydrofuro[3,4-c]quinolin-8- yl)((4aR,9aS)-7-(difluoromethoxy)-2,3,9,9a-tetrahydroindeno[2,l-b][l,4]oxazin-4(4aH)- yl)methanone, isomer 4 (2.3 mg, 8%) as a white solid with retention time at 17.26 minute.

[1707] rel-((R)-4-amino-l ,3,6,7,8,9-hexahydrofuro[3,4-c]quinolin-8-yl)((4aR,9aS)-7- (difluoromethoxy)-2,3 ,9,9a-tetrahydroindeno [2, 1 -b] [ 1 ,4] oxazin-4(4aH)-yl)methanone, isomer 1: MS ESI calculated for C24H25F2N3O4 [M+H]⁺, 458.18; found, 458.25. 'H NMR (400 MHz, DMSO-de) 5 7.37 - 6.93 (m, 4H), 5.77 (s, 2H), 5.63 - 5.45 (m, 1H), 4.94 - 4.81 (m, 4H), 4.33 - 4.30 (m, 1H), 4.28 - 3.80 (m, 1H), 3.69 - 3.67 (m, 1H), 3.46 - 3.39 (m, 1H),

3.15 - 2.98 (m, 3H), 2.82 - 2.55 (m, 5H), 2.03 - 1.75 (m, 2H).

[1708] rel-((R)-4-amino-l ,3,6,7,8,9-hexahydrofuro[3,4-c]quinolin-8-yl)((4aR,9aS)-7- (difluoromethoxy)-2,3 ,9,9a-tetrahydroindeno [2, 1 -b] [ 1 ,4] oxazin-4(4aH)-yl)methanone, isomer 2: MS ESI calculated for C24H25F2N3O4 [M+H]⁺, 458.18; found, 458.25. 'H NMR (400 MHz, DMSO-cfc) 6 7.37 - 6.90 (m, 4H), 5.74 (s, 2H), 5.63 - 5.40 (m, 1H), 4.92 - 4.81 (m, 4H), 4.35 - 4.30 (m, 1H), 4.20 - 3.68 (m, 1H), 3.65 - 3.62 (m, 1H), 3.51 - 3.42 (m, 2H),

3.16 - 3.14 (m, 2H), 3.11 - 2.74 (m, 5H), 2.09 -2.08 (m, 1H), 1.81 -1.78 (m, 1H).

[1709] rel-((R)-4-amino-l,3,6,7,8,9-hexahydrofuro[3,4-c]quinolin-8-yl)((4aR,9aS)-7- (difluoromethoxy)-2,3 ,9,9a-tetrahydroindeno [2, 1 -b] [ 1 ,4] oxazin-4(4aH)-yl)methanone, isomer 3: MS ESI calculated for C24H25F2N3O4 [M+H]⁺, 458.18; found, 458.25. 'H NMR (400 MHz, DMSO- ₆) 5 7.37 - 6.90 (m, 4H), 5.74 (s, 2H), 5.63 - 5.40 (m, 1H), 4.92 - 4.81 (m, 4H), 4.35 - 4.30 (m, 1H), 4.20 - 3.68 (m, 1H), 3.65 - 3.62 (m, 1H), 3.51 - 3.42 (m, 2H),

[1710] rel-((R)-4-amino-l,3,6,7,8,9-hexahydrofuro[3,4-c]quinolin-8-yl)((4aR,9aS)-7- (difluoromethoxy)-2,3 ,9,9a-tetrahydroindeno [2, 1 -b] [ 1 ,4] oxazin-4(4aH)-yl)methanone, isomer 4: MS ESI calculated for C24H25F2N3O4 [M+H]⁺, 458.18; found, 458.25. 'H NMR (400 MHz, DMSO- fc) 57.37 - 6.93 (m, 4H), 5.77 (s, 2H), 5.63 - 5.45 (m, 1H), 4.94 - 4.81 (m, 4H), 4.33 - 4.30 (m, 1H), 4.28 - 3.80 (m, 1H), 3.69 - 3.67 (m, 1H), 3.46 - 3.39 (m, 1H), 3.15 - 2.98 (m, 3H), 2.82 - 2.55 (m, 5H), 2.03 - 1.75 (m, 2H).

Example 6: rel-((R)-4-amino-l,3,6,7,8,9-hexahydrofuro[3,4-c]quinolin-8-yl)((4aR,9bR)-7- (difluoromethoxy)-3,4,4a,9b-tetrahydrobenzofuro[3,2-b]pyridin- 1 (2H)-yl)methanone, isomer 3

Step 1: 1: 1:1:1 mixture of rel-((R)-4-amino-l,3,6,7,8,9-hexahydrofuro[3,4-c]quinolin-8- yl)((4aR,9bR)-7-(difluoromethoxy)-3,4,4a,9b-tetrahydrobenzofuro[3,2-b]pyridin-l(2H)- yl)methanone, isomer 1 and rel-((R)-4-amino-l,3,6,7,8,9-hexahydrofuro[3,4-c]quinolin-8- yl)((4aR,9bR)-7-(difluoromethoxy)-3,4,4a,9b-tetrahydrobenzofuro[3,2-b]pyridin-l(2H)- yl)methanone, isomer 2 and rel-((R)-4-amino-l,3,6,7,8,9-hexahydrofuro[3,4-c]quinolin-8- yl)((4aR,9bR)-7-(difluoromethoxy)-3,4,4a,9b-tetrahydrobenzofuro[3,2-b]pyridin-l(2H)- yl)methanone, isomer 3 and rel-((R)-4-amino-l,3,6,7,8,9-hexahydrofuro[3,4-c]quinolin-8- yl)((4aR,9bR)-7-(difluoromethoxy)-3,4,4a,9b-tetrahydrobenzofuro[3,2-b]pyridin-l(2H)- yl)methanone, isomer 4

[1711] To a stirred solution of intermediate Al 1 (110 mg, 0.46 mmol) and intermediate CAI (107 mg, 0.46 mmol) in DMAC (1.5 mL) were added TEA (138 mg, 1.37 mmol) and bis(2-oxo-l,3-oxazolidin-3-yl)phosphinoyl chloride (174 mg, 0.68 mmol) at room temperature. The resulting mixture was stirred at room temperature for 2 h. The reaction mixture was quenched by water and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under vacuum. The residue was purified by prep-HPLC with the following conditions: [Column: XSelect CSH Prep C18 OBD Column, 19*250 mm, 5pm; Mobile Phase A: Water (10 mmol/L NH4HCO3), Mobile Phase B: MeOH; Flow rate: 20 mL/min; Gradient: 55% B to 65% B in 10 min; Wave Length: 254/220 nm] to afford 1: 1: 1: 1 mixture of rel-((R)- 4-amino-l,3,6,7,8,9-hexahydrofuro[3,4-c]quinolin-8-yl)((4aR,9bR)-7-(difhioromethoxy)- 3,4,4a,9b-tetrahydrobenzofuro[3,2-b]pyridin-l(2H)-yl)methanone, isomer 1 and rel-((R)-4- amino-l,3,6,7,8,9-hexahydrofuro[3,4-c]quinolin-8-yl)((4aR,9bR)-7-(difluoromethoxy)- 3,4,4a,9b-tetrahydrobenzofuro[3,2-b]pyridin-l(2H)-yl)methanone, isomer 2 and rel-((R)-4- amino-l,3,6,7,8,9-hexahydrofuro[3,4-c]quinolin-8-yl)((4aR,9bR)-7-(difluoromethoxy)- 3,4,4a,9b-tetrahydrobenzofuro[3,2-b]pyridin-l(2H)-yl)methanone, isomer 3 and rel-((R)-4- amino-l,3,6,7,8,9-hexahydrofuro[3,4-c]quinolin-8-yl)((4aR,9bR)-7-(difluoromethoxy)- 3,4,4a,9b-tetrahydrobenzofuro[3,2-b]pyridin-l(2H)-yl)methanone, isomer 4 (95 mg, 45%) as a white solid. MS ESI calculated for C24H25F2N3O4 [M+H]⁺, 458.18; found, 458.20. 'H NMR (400 MHz, DMSO- fe) 5 7.50 - 6.96 (m, 2H), 6.80 - 6.60 (m, 2H), 6.23 - 5.82 (m, 1H), 5.67 (s, 2H), 5.26 - 4.99 (m, 1H), 5.02 - 4.85 (m, 2H), 4.83 - 4.82 (m, 2H), 4.29 - 3.70 (m, 1H), 3.28 - 2.96 (m, 1H), 2.97 - 2.54 (m, 4H), 2.47 - 2.28 (m, 1H), 1.92 - 1.87 (m, 2H), 1.82 - 1.71 (m, 3H), 1.66 - 1.43 (m, 1H).

Step 2: rel-((R)-4-amino-l,3,6,7,8,9-hexahydrofuro[3,4-c]quinolin-8-yl)((4aR,9bR)-7- (difhioromethoxy)-3,4,4a,9b-tetrahydrobenzofuro[3,2-b]pyridin- 1 (2H)-yl)methanone, isomer 3

[1712] To the 1 : 1 : 1 : 1 mixture of rel-((R)-4-amino- 1 ,3,6,7,8,9-hexahydrofuro[3,4- c]quinolin-8-yl)((4aR,9bR)-7-(difluoromethoxy)-3,4,4a,9b-tetrahydrobenzofuro[3,2- b]pyridin-l(2H)-yl)methanone, isomer 1 and rel-((R)-4-amino-l,3,6,7,8,9- hexahydrofuro[3,4-c]quinolin-8-yl)((4aR,9bR)-7-(difluoromethoxy)-3,4,4a,9b- tetrahydrobenzofuro[3,2-b]pyridin-l(2H)-yl)methanone, isomer 2 and rel-((R)-4-amino- l,3,6,7,8,9-hexahydrofuro[3,4-c]quinolin-8-yl)((4aR,9bR)-7-(difluoromethoxy)-3,4,4a,9b- tetrahydrobenzofuro[3,2-b]pyridin-l(2H)-yl)methanone, isomer 3 and rel-((R)-4-amino- l,3,6,7,8,9-hexahydrofuro[3,4-c]quinolin-8-yl)((4aR,9bR)-7-(difluoromethoxy)-3,4,4a,9b- tetrahydrobenzofuro[3,2-b]pyridin-l(2H)-yl)methanone, isomer 4 (85 mg) was separated by Prep-Chiral-HPLC with the following conditions: [Column: CHIRALPAK IC, 2*25 cm, 5 pm; Mobile Phase A: Hex (0.3% IPAMIN), Mobile Phase B: EtOH: DCM=1: 1-HPLC; Flow rate: 20 mL/min; Gradient: 60% B to 60% B in 18 min; Wave Length: 220/254 nm; RTl(min): 5.95; RT2(min): 9.07; RT3(min): 14.51; Sample Solvent: EtOH: DCM=1: 1- HPLC; Injection Volume: 0.7 mL; Number Of Runs: 6] to afford fraction A (35 mg) with the retention time at 5.95 minute. The chiral resolution also afford rel-((R)-4-amino-l , 3, 6, 7,8,9- hexahydrofuro[3,4-c]quinolin-8-yl)((4aR,9bR)-7-(difluoromethoxy)-3,4,4a,9b- tetrahydrobenzofuro[3,2-b]pyridin-l(2H)-yl)methanone, isomer 3 (9.2 mg, 11%) as a white solid with the retention time at 9.07 minute and rel-((R)-4-amino-l,3,6,7,8,9- hexahydrofuro[3,4-c]quinolin-8-yl)((4aR,9bR)-7-(difluoromethoxy)-3,4,4a,9b- tetrahydrobenzofuro[3,2-b]pyridin-l(2H)-yl)methanone, isomer 4) (21.6 mg, 25%) as a white solid with the retention time at 14.54 minute.

[1713] The fraction A (35 mg) was further separated by Prep-Chiral-HPLC with the following conditions: [Column: CHIRALPAK IF, 2*25 cm, 5 pm; Mobile Phase A: Hex (0.2% IPAMine)— HPLC, Mobile Phase B: EtOH: DCM=1: 1-HPLC; Flow rate: 20 mL/min; Gradient: 35% B to 35% B in 19 min; Wave Length: 220/254 nm; RTl(min): 12.61;

RT2(min): 15.16; Sample Solvent: EtOH: DCM=1: 1— HPLC; Injection Volume: 0.7 mL; Number Of Runs: 4] to afford rel-((R)-4-amino-l,3,6,7,8,9-hexahydrofuro[3,4-c]quinolin-8- yl)((4aR,9bR)-7-(difhioromethoxy)-3,4,4a,9b-tetrahydrobenzofuro[3,2-b]pyridin-l(2H)- yl)methanone, isomer 1 (8.9 mg, 10%) as a white solid with the retention time at 12.61 minute and rel-((R)-4-amino- 1,3, 6,7,8, 9-hexahydrofuro[3,4-c]quinolin-8-yl)((4aR,9bR)-7- (difluoromethoxy)-3,4,4a,9b-tetrahydrobenzofuro[3,2-b]pyridin- 1 (2H)-yl)methanone, isomer 2 (18.2 mg, 21%) as a white solid with the retention time at 15.16 minute. The chirality of four isomers were arbitrarily assigned.

[1714] rel-((R)-4-amino-l,3,6,7,8,9-hexahydrofuro[3,4-c]quinolin-8-yl)((4aR,9bR)-7- (difhioromethoxy)-3,4,4a,9b-tetrahydrobenzofuro[3,2-b]pyridin- 1 (2H)-yl)methanone, isomer 1: MS ESI calculated for C24H25F2N3O4 [M+H]⁺, 458.18; found, 458.25. 'H NMR (400 MHz, DMSO-J₆) 8 'IA'1 - 7.00 (m, 2H), 6.80 - 6.65 (m, 2H), 6.12 - 5.94 (m, 1H), 5.73 (s, 2H), 5.08 - 5.04 (m, 1H), 4.99 - 4.71 (m, 4H), 4.17 - 3.74 (m, 1H), 3.28 - 3.02 (m, 1H), 2.92 - 2.85 (m, 1H), 2.83 - 2.57 (m, 3H), 2.48 - 2.34 (m, 1H), 2.11 - 1.86 (m, 2H), 1.81 - 1.76 (m, 3H), 1.60 - 1.58 (m, 1H).

[1715] rel-((R)-4-amino-l,3,6,7,8,9-hexahydrofuro[3,4-c]quinolin-8-yl)((4aR,9bR)-7- (difluoromethoxy)-3,4,4a,9b-tetrahydrobenzofuro[3,2-b]pyridin- 1 (2H)-yl)methanone, isomer 2: MS ESI calculated for C24H25F2N3O4 [M+H]⁺, 458.18; found, 458.20. 'H NMR (400 MHz, DMSO-d₆) 8 7.46 - 6.99 (m, 2H), 6.78 - 6.61 (m, 2H), 6.13 - 5.93 (m, 1H), 5.70 (s, 2H), 5.15 - 5.03 (m, 1H), 4.99 - 4.73 (m, 4H), 4.25 - 3.76 (m, 1H), 3.25 - 2.98 (m, 1H), 2.97 - 2.78 (m, 1H), 2.78 - 2.54 (m, 3H), 2.48 - 2.34 (m, 1H), 2.07 - 1.85 (m, 2H), 1.85 - 1.65 (m, 3H), 1.65 - 1.44 (m, 1H). [1716] rel-((R)-4-amino-l,3,6,7,8,9-hexahydrofuro[3,4-c]quinolin-8-yl)((4aR,9bR)-7- (difluoromethoxy)-3,4,4a,9b-tetrahydrobenzofuro[3,2-b]pyridin- 1 (2H)-yl)methanone, isomer 3: MS ESI calculated for C24H25F2N3O4 [M+H]⁺, 458.18; found, 458.20. 'H NMR (400 MHz, DMSO-de) 57.47 - 7.00 (m, 2H), 6.80 - 6.65 (m, 2H), 6.12 - 5.94 (m, 1H), 5.73 (s, 2H), 5.08 - 5.04 (m, 1H), 4.99 - 4.71 (m, 4H), 4.17 - 3.74 (m, 1H), 3.28 - 3.02 (m, 1H), 2.92 - 2.85 (m, 1H), 2.83 - 2.57 (m, 3H), 2.48 - 2.34 (m, 1H), 2.11 - 1.86 (m, 2H), 1.81 - 1.76 (m, 3H), 1.60 - 1.58 (m, 1H).

[1717] rel-((R)-4-amino-l,3,6,7,8,9-hexahydrofuro[3,4-c]quinolin-8-yl)((4aR,9bR)-7- (difluoromethoxy)-3,4,4a,9b-tetrahydrobenzofuro[3,2-b]pyridin- 1 (2H)-yl)methanone, isomer 4: MS ESI calculated for C24H25F2N3O4 [M+H]⁺, 458.18; found, 458.20. 'H NMR (400 MHz, DMSO-cfc) 5 7.46 - 6.99 (m, 2H), 6.78 - 6.61 (m, 2H), 6.13 - 5.93 (m, 1H), 5.70 (s, 2H), 5.15 - 5.03 (m, 1H), 4.99 - 4.73 (m, 4H), 4.25 - 3.76 (m, 1H), 3.25 - 2.98 (m, 1H), 2.97 - 2.78 (m, 1H), 2.78 - 2.54 (m, 3H), 2.48 - 2.34 (m, 1H), 2.07 - 1.85 (m, 2H), 1.85 - 1.65 (m, 3H), 1.65 - 1.44 (m, 1H).

Example 7: rel-((R)-4-amino-l,3,6,7,8,9-hexahydrofuro[3,4-c]quinolin-8-yl)((4aS,9bS)-7- (difluoromethoxy)-2,3 ,4, 4a, 5 ,9b-hexahydro- 1 H-indeno [ 1 ,2-b]pyridin- 1 -yl)methanone, isomer 4

Step 1: 1:1:1:1 mixture of rel-((R)-4-amino-l, 3, 6,7,8, 9-hexahydrofuro[3,4-c]quinolin-8- yl)((4aS ,9bS)-7-(difluoromethoxy)-2,3 ,4, 4a, 5 ,9b-hexahydro- 1 H-indeno [ 1 ,2-b]pyridin- 1 - yl)methanone, isomer 1 and rel-((R)-4-amino-l,3,6,7,8,9-hexahydrofuro[3,4-c]quinolin-8- yl)((4aS ,9bS)-7-(difluoromethoxy)-2,3 ,4, 4a, 5 ,9b-hexahydro- 1 H-indeno [ 1 ,2-b]pyridin- 1 - yl)methanone, isomer 2 and rel-((R)-4-amino-l,3,6,7,8,9-hexahydrofuro[3,4-c]quinolin-8- yl)((4aS ,9bS)-7-(difluoromethoxy)-2,3 ,4, 4a, 5 ,9b-hexahydro- 1 H-indeno [ 1 ,2-b]pyridin- 1 - yl)methanone, isomer 3 and rel-((R)-4-amino-l,3,6,7,8,9-hexahydrofuro[3,4-c]quinolin-8- yl)((4aS ,9bS)-7-(difluoromethoxy)-2,3 ,4, 4a, 5 ,9b-hexahydro- 1 H-indeno [ 1 ,2-b]pyridin- 1 - yl)methanone, isomer 4

[1718] To a stirred solution of intermediate A12 (100 mg, 0.42 mmol) in DMF (5 mL) were added intermediate CAI (98 mg, 0.42 mmol), HATU (238 mg, 0.63 mmol) and DIEA (162 mg, 1.26 mmol) at 25 °C. The resulting mixture was stirred at room temperature for 1 h. The reaction mixture was quenched with water and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered through paper, and concentrated under vacuum. The residue was purified by prep- HPLC with the following conditions: [Column: YMC- Actus Triart C18 20 *250 mm, 5 pm, 12nm; Mobile Phase A: Water (10 nunol/L NH4HCO3), Mobile Phase B: ACN; Flow rate: 60 mL/min; Gradient: 40% B to 55% B in 10 min; Wave Length: 254/220 nm] to afford rac-8- [(4aR,9bR)-7-(difluoromethoxy)-2H,3H,4H,4aH,5H,9bH-indeno[ 1 ,2-b]pyridine- 1 -carbonyl]- lH,3H,6H,7H,8H,9H-furo[3,4-c]quinolin-4-amine (40 mg, 23%) as a white solid. MS (ESI) calc’d for (C25H27F2N3O3) [M+H]⁺, 456.20; found 456.20.

Step 2: rel-((R)-4-amino-l,3,6,7,8,9-hexahydrofuro[3,4-c]quinofin-8-yl)((4aS,9bS)-7- (difluoromethoxy)-2,3 ,4, 4a, 5 ,9b-hexahydro- 1 H-indeno [ 1 ,2-b]pyridin- 1 -yl)methanone, isomer 4

[1719] To a 1 : 1 : 1: 1 mixture of rel-((R)-4-amino-l,3,6,7,8,9-hexahydrofuro[3,4-c]quinolin- 8-yl)((4aS,9bS)-7-(difhioromethoxy)-2,3,4,4a,5,9b-hexahydro-lH-indeno[l,2-b]pyridin-l- yl)methanone, isomer 1 and rel-((R)-4-amino-l,3,6,7,8,9-hexahydrofuro[3,4-c]quinolin-8- yl)((4aS ,9bS)-7-(difluoromethoxy)-2,3 ,4, 4a, 5 ,9b-hexahydro- 1 H-indeno [ 1 ,2-b]pyridin- 1 - yl)methanone, isomer 2 and rel-((R)-4-amino-l,3,6,7,8,9-hexahydrofuro[3,4-c]quinolin-8- yl)((4aS ,9bS)-7-(difluoromethoxy)-2,3 ,4, 4a, 5 ,9b-hexahydro- 1 H-indeno [ 1 ,2-b]pyridin- 1 - yl)methanone, isomer 3 and rel-((R)-4-amino-l,3,6,7,8,9-hexahydrofuro[3,4-c]quinolin-8- yl)((4aS ,9bS)-7-(difluoromethoxy)-2,3 ,4, 4a, 5 ,9b-hexahydro- 1 H-indeno [ 1 ,2-b]pyridin- 1 - yl)methanone, isomer 4 (43 mg) was separated by prep-chiral HPLC with the following conditions: [Column: CHIRAL ART Cellulose-SC, 2*25 cm, 5 pm; Mobile Phase A: Hex (0.2% IPAMine)— HPLC, Mobile Phase B: EtOH: DCM= 1: 1-HPLC; Flow rate: 20 mL/min; Gradient: 50% B to 50% B in 9.5 min; Wave Length: 220/254 nm; RT1 (min): 6.92; RT2 (min): 7.68; RT3 (min): 10.23; RT4 (min): 14.34; Sample Solvent: EtOH: DCM= 1: 1- HPLC; Injection Volume: 0.6 mL; Number Of Runs: 4] to afford rel-((R)-4-amino- l,3,6,7,8,9-hexahydrofuro[3,4-c]quinolin-8-yl)((4aS,9bS)-7-(difluoromethoxy)-2,3,4,4a,5,9b- hexahydro-lH-indeno[l,2-b]pyridin-l-yl)methanone, isomer 1 (6.4 mg, 15%) as a white solid with retention time at 6.92 minute and rel-((R)-4-amino-l,3,6,7,8,9-hexahydrofuro[3,4- c]quinolin-8-yl)((4aS,9bS)-7-(difluoromethoxy)-2,3,4,4a,5,9b-hexahydro-lH-indeno[l,2- b]pyridin-l-yl)methanone, isomer 2 (9.1 mg, 22%) as a white solid with retention time at 7.68 minute.

[1720] The chiral separation also afforded rel-((R)-4-amino-l,3,6,7,8,9-hexahydrofuro[3,4- c]quinolin-8-yl)((4aS,9bS)-7-(difluoromethoxy)-2,3,4,4a,5,9b-hexahydro-lH-indeno[l,2- b]pyridin-l-yl)methanone, isomer 3 (9.7 mg, 24%) as a white solid with retention time at 10.23 minute and rel-((R)-4-amino-l,3,6,7,8,9-hexahydrofuro[3,4-c]quinolin-8- yl)((4aS ,9bS)-7-(difluoromethoxy)-2,3 ,4, 4a, 5 ,9b-hexahydro- 1 H-indeno [ 1 ,2-b]pyridin- 1 - yl)methanone, isomer 4 (6.3 mg, 15%) as a white solid with retention time at 14.34 minute. The chiral centers were assigned arbitrarily.

[1721] rel-((R)-4-amino-l,3,6,7,8,9-hexahydrofuro[3,4-c]quinolin-8-yl)((4aS,9bS)-7- (difluoromethoxy)-2,3 ,4, 4a, 5 ,9b-hexahydro- 1 H-indeno [ 1 ,2-b]pyridin- 1 -yl)methanone, i somer 1: MS ESI calculated for (C25H27F2N3O3) [M+H]⁺, 456.20; found 456.20. 'H NMR (400 MHz, DMSO-J₆) 8 7.44 - 7.17 (m, 1H), 7.12 (d, J= 9.2 Hz, 1H), 7.06 - 6.86 (m, 2H), 6.03 - 5.44 (m, 3H), 5.00 - 4.73 (m, 4H), 4.49 - 3.79 (m, 1H), 3.20 - 2.96 (m, 2H), 2.82 - 2.51 (m, 5H), 2.38 - 2.15 (m, 1H), 2.03 - 1.92 (m, 1H), 1.91 - 1.66 (m, 2H), 1.60 - 1.34 (m, 2H), 1.31 - 1.16 (m, 1H), 1.06 - 0.89 (m, 1H).

[1722] rel-((R)-4-amino-l,3,6,7,8,9-hexahydrofuro[3,4-c]quinolin-8-yl)((4aS,9bS)-7- (difluoromethoxy)-2,3 ,4, 4a, 5 ,9b-hexahydro- 1 H-indeno [ 1 ,2-b]pyridin- 1 -yl)methanone, isomer 2: MS ESI calculated for (C25H27F2N3O3) [M+H]⁺, 456.20; found 456.20. 'H NMR (400 MHz, DMSO-J₆) 8 7.42 - 7.16 (m, 1H), 7.15 - 7.09 (m, 1H), 7.05 - 6.79 (m, 2H), 5.94 - 5.46 (m, 3H), 4.97 - 4.69 (m, 4H), 4.51 - 3.88 (m, 1H), 3.22 - 2.96 (m, 2H), 2.88 - 2.51 (m, 6H), 2.27 - 1.96 (m, 2H), 1.86 - 1.62 (m, 2H), 1.58 - 1.50 (m, 1H), 1.47 - 1.20 (m, 1H), 1.11 - 0.89 (m, 1H).

[1723] rel-((R)-4-amino-l,3,6,7,8,9-hexahydrofuro[3,4-c]quinolin-8-yl)((4aS,9bS)-7- (difluoromethoxy)-2,3 ,4, 4a, 5 ,9b-hexahydro- 1 H-indeno [ 1 ,2-b]pyridin- 1 -yl)methanone, i somer 3: MS ESI calculated for (C25H27F2N3O3) [M+H]⁺, 456.20; found 456.20. 'H NMR (400 MHz, DMSO-de) 8 7.42 - 7.16 (m, 1H), 7.15 - 7.09 (m, 1H), 7.05 - 6.79 (m, 2H), 5.94 - 5.46 (m, 3H), 4.97 - 4.69 (m, 4H), 4.51 - 3.88 (m, 1H), 3.22 - 2.96 (m, 2H), 2.88 - 2.51 (m, 6H), 2.27 - 1.96 (m, 2H), 1.86 - 1.62 (m, 2H), 1.58 - 1.50 (m, 1H), 1.47 - 1.20 (m, 1H), 1.11 - 0.89 (m, 1H).

[1724] rel-((R)-4-amino-l,3,6,7,8,9-hexahydrofuro[3,4-c]quinolin-8-yl)((4aS,9bS)-7- (difluoromethoxy)-2,3 ,4, 4a, 5 ,9b-hexahydro- 1 H-indeno [ 1 ,2-b]pyridin- 1 -yl)methanone, isomer 4 : MS ESI calculated for (C25H27F2N3O3) [M+H]⁺, 456.20; found 456.25. 'H NMR (400 MHz, DMSO- ₆) 8 7.44 - 7.17 (m, 1H), 7.12 (d, J= 9.2 Hz, 1H), 7.06 - 6.86 (m, 2H), 6.03 - 5.44 (m, 3H), 5.00 - 4.73 (m, 4H), 4.49 - 3.79 (m, 1H), 3.20 - 2.96 (m, 2H), 2.82 - 2.51 (m, 5H), 2.38 - 2.15 (m, 1H), 2.03 - 1.92 (m, 1H), 1.91 - 1.66 (m, 2H), 1.60 - 1.34 (m, 2H), 1.31 - 1.16 (m, 1H), 1.06 - 0.89 (m, 1H).

Example 8: rel-((R)-4-amino-l,3,6,7,8,9-hexahydrofuro[3,4-c]quinolin-8-yl)((4aR,10bR)-8- (trifluoromethyl)-2,3,4,4a,6,10b-hexahydro-lH-isochromeno[4,3-b]pyridin-l-yl)methanone, isomer 3

Step 1: 1:1:1:1 mixture of rel-((R)-4-amino-l,3,6,7,8,9-hexahydrofuro[3,4-c]quinolin-8- yl)((4aR,10bR)-8-(trifluoromethyl)-2,3,4,4a,6,10b-hexahydro-lH-isochromeno[4,3- b]pyridin-l-yl)methanone, isomer 1 and rel-((R)-4-amino-l,3,6,7,8,9-hexahydrofuro[3,4- c]quinolin-8-yl)((4aR,10bR)-8-(trifluoromethyl)-2,3,4,4a,6,10b-hexahydro-lH- isochromeno[4,3-b]pyridin-l-yl)methanone, isomer 2 and rel-((R)-4-amino-l,3,6,7,8,9- hexahydrofuro[3,4-c]quinolin-8-yl)((4aR,10bR)-8-(trifluoromethyl)-2,3,4,4a,6,10b- hexahydro-lH-isochromeno[4,3-b]pyridin-l-yl)methanone, isomer 3 and rel-((R)-4-amino- l,3,6,7,8,9-hexahydrofuro[3,4-c]quinolin-8-yl)((4aR,10bR)-8-(trifluoromethyl)-

2, 3, 4, 4a, 6, 1 Ob-hexahydro- lH-isochromeno[4,3-b]pyridin- 1 -yl)methanone, isomer 4

[1725] To a solution of intermediate CAI (100 mg, 0.43 mmol) and intermediate A2 (116 mg, 0.43 mmol) in DMF (2 mL) were added TEA (345 mg, 3.42 mmol) and TBTU (165 mg, 0.51 mmol) at room temperature. The mixture was stirred at room temperature for 16 h. The reaction mixture was quenched by the addition of water and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under vacuum. The residue was purified by Prep-HPLC with the following conditions: [Column: Xselect CSH C18 OBD Column 30*150 mm 5pm; Mobile Phase A: Water (0.1% FA), Mobile Phase B: ACN; Flow rate: 60 mL/min; Gradient: 5% B to 5% B in 2 min, 10% B to 28% B in 15 min; Wave Length: 254/220 nm; RTl(min): 13.5] to afford 1: 1:1:1 mixture of rel-((R)-4-amino-l,3,6,7,8,9-hexahydrofuro[3,4-c]quinolin-8- yl)((4aR,10bR)-8-(trifhioromethyl)-2,3,4,4a,6,10b-hexahydro-lH-isochromeno[4,3- b]pyridin-l-yl)methanone, isomer 1 and rel-((R)-4-amino-l,3,6,7,8,9-hexahydrofuro[3,4- c]quinolin-8-yl)((4aR,10bR)-8-(trifluoromethyl)-2,3,4,4a,6,10b-hexahydro-lH- isochromeno[4,3-b]pyridin-l-yl)methanone, isomer 2 and rel-((R)-4-amino-l,3,6,7,8,9- hexahydrofuro[3,4-c]quinolin-8-yl)((4aR,10bR)-8-(trifluoromethyl)-2,3,4,4a,6,10b- hexahydro- lH-isochromeno[4,3-b]pyridin-l-yl)methanone, isomer 3 and rel-((R)-4-amino- l,3,6,7,8,9-hexahydrofuro[3,4-c]quinolin-8-yl)((4aR,10bR)-8-(trifluoromethyl)- 2,3,4,4a,6,10b-hexahydro-lH-isochromeno[4,3-b]pyridin-l-yl)methanone, isomer 4 formate (52.0 mg, 22%) as a white solid. MS ESI calculated for C25H26F3N3O3 [M+H]⁺, 474.19; found, 474.20. 'H NMR (400 MHz, DMSO-J₆) 8 8.16 (s, 1H), 7.74 - 7.49 (m, 2H), 7.39 - 7.10 (m, 1H), 5.92 - 5.37 (m, 3H), 5.00 - 4.68 (m, 6H), 4.41 - 3.78 (m, 2H), 3.22 - 3.12 (m, 1H), 2.94 - 2.45 (m, 5H), 2.18 - 1.91 (m, 1H), 1.91 - 1.72 (m, 2H), 1.72 - 1.33 (m, 3H).

Step 2: rel-((R)-4-amino-l,3,6,7,8,9-hexahydrofuro[3,4-c]quinolin-8-yl)((4aR,10bR)-8- (trifluoromethyl)-2,3,4,4a,6,10b-hexahydro-lH-isochromeno[4,3-b]pyridin-l-yl)methanone, isomer 3

[1726] To a 1 : 1 : 1: 1 mixture of rel-((R)-4-amino-l,3,6,7,8,9-hexahydrofuro[3,4-c]quinolin- 8-yl)((4aR,10bR)-8-(trifluoromethyl)-2,3,4,4a,6,10b-hexahydro-lH-isochromeno[4,3- b]pyridin-l-yl)methanone, isomer 1 and rel-((R)-4-amino-l,3,6,7,8,9-hexahydrofuro[3,4- c]quinolin-8-yl)((4aR, 10bR)-8-(trifluoromethyl)-2,3,4,4a,6, 1 Ob-hexahydro- 1 H- isochromeno[4,3-b]pyridin-l-yl)methanone, isomer 2 and rel-((R)-4-amino-1 ,3,6,7,8,9- hexahydrofuro[3,4-c]quinolin-8-yl)((4aR,10bR)-8-(trifluoromethyl)-2,3,4,4a,6,10b- hexahydro-lH-isochromeno[4,3-b]pyridin-l-yl)methanone, isomer 3 and rel-((R)-4-amino-

1.3.6.7.8.9-hexahydrofuro[3,4-c]quinolin-8-yl)((4aR,10bR)-8-(trifluoromethyl)- 2,3,4,4a,6,10b-hexahydro-lH-isochromeno[4,3-b]pyridin-l-yl)methanone, isomer 4 formate (50 mg) was separated by Prep-chiral HPLC with the following conditions: [Column: CHIRAL ART Cellulose-SZ 2*25 cm, 5 pm; Mobile Phase A: Hex(0.3% IPAMIN), Mobile Phase B: EtOH: DCM=1: 1— HPLC; Flow rate: 20 mL/min; Gradient: 40% B to 40% B in 20 min; Wave Length: 220/254 nm; RTl(min): 9.2; RT2(min): 12.06; RT3(min): 14.87; RT4(min): 17.04; Sample Solvent: EtOH: DCM=1: 1— HPLC; Injection Volume: 0.35 mL; Number Of Runs: 6] to afford rel-((R)-4-amino-l,3,6,7,8,9-hexahydrofuro[3,4-c]quinolin-8- yl)((4aR,10bR)-8-(trifhioromethyl)-2,3,4,4a,6,10b-hexahydro-lH-isochromeno[4,3- b]pyridin-l-yl)methanone, isomer 1 (5.3 mg) as a white solid with retention time at 9.2 minute. The chiral separation also afford rel-((R)-4-amino-l,3,6,7,8,9-hexahydrofuro[3,4- c]quinolin-8-yl)((4aR, 10bR)-8-(trifhioromethyl)-2,3,4,4a,6, 1 Ob-hexahydro- 1H- isochromeno[4,3-b]pyridin-l-yl)methanone, isomer 2 as a white solid with retention time at 12.06 minute. The chiral separation also afford rel-((R)-4-amino-l,3,6,7,8,9- hexahydrofuro[3,4-c]quinolin-8-yl)((4aR,10bR)-8-(trifluoromethyl)-2,3,4,4a,6,10b- hexahydro-lH-isochromeno[4,3-b]pyridin-l-yl)methanone, isomer 3 (6.0 mg) as a white solid with retention time at 14.87 minute. The chiral separation also afford rel-((R)-4-amino-

1 .3.6.7.8.9-hexahydrofuro[3,4-c]quinolin-8-yl)((4aR, 10bR)-8-(trifluoromethyl)- 2,3,4,4a,6,10b-hexahydro-lH-isochromeno[4,3-b]pyridin-l-yl)methanone, isomer 4 (7.0 mg) as a white solid with retention time at 17.04 minute. The chiral centers were assigned arbitrarily. [1727] rel-((R)-4-amino-l,3,6,7,8,9-hexahydrofuro[3,4-c]quinolin-8-yl)((4aR,10bR)-8- (trifluoromethyl)-2,3,4,4a,6,10b-hexahydro-lH-isochromeno[4,3-b]pyridin-l-yl)methanone, isomer 1: MS ESI calculated for C25H26F3N3O3 [M+H]⁺, 474.19; found, 474.20. NMR (400 MHz, DMSO-de) 57.68 - 7.61 (m, 1H), 7.58 - 7.53 (m, 1H), 7.31 - 7.15 (m, 1H), 5.89 - 5.34 (m, 3H), 4.97 - 4.74 (m, 6H), 4.42 - 3.81 (m, 2H), 3.21 - 3.05 (m, 1H), 2.92 - 2.55 (m, 4H), 2.49 - 2.45 (m, 1H), 2.20 - 1.96 (m, 1H), 1.89 - 1.74 (m, 2H), 1.73 - 1.62 (m, 2H), 1.61 - 1.35 (m, 1H).

[1728] rel-((R)-4-amino-l,3,6,7,8,9-hexahydrofuro[3,4-c]quinobn-8-yl)((4aR,10bR)-8- (trifhioromethyl)-2,3,4,4a,6,10b-hexahydro-lH-isochromeno[4,3-b]pyridin-l-yl)methanone, isomer 2: MS ESI calculated for C25H26F3N3O3 [M+H]⁺, 474.19; found, 474.20. 'H NMR (400 MHz, DMSO-cfc) 8 7.73 - 7.52 (m, 2H), 7.33 - 7.15 (m, 1H), 5.86 - 5.38 (m, 3H), 4.95 - 4.76 (m, 6H), 4.39 - 3.82 (m, 2H), 3.20 - 3.11 (m, 1H), 2.83 - 2.55 (m, 5H), 2.15 - 1.92 (m, 1H), 1.89 - 1.72 (m, 2H), 1.70 - 1.33 (m, 3H).

[1729] rel-((R)-4-amino-l,3,6,7,8,9-hexahydrofuro[3,4-c]quinolin-8-yl)((4aR,10bR)-8- (trifluoromethyl)-2,3,4,4a,6,10b-hexahydro-lH-isochromeno[4,3-b]pyridin-l-yl)methanone, isomer 3: MS ESI calculated for C25H26F3N3O3 [M+H]⁺, 474.19; found, 474.20.' H NMR (400 MHz, DMSO- fc) 8 7.74 - 7.50 (m, 2H), 7.34 - 7.17 (m, 1H), 5.87 - 5.35 (m, 3H), 4.95 - 4.76 (m, 6H), 4.38 - 3.81 (m, 2H), 3.21 - 3.13 (m, 1H), 2.89 - 2.52 (m, 5H), 2.13 - 1.91 (m, 1H), 1.89 - 1.71 (m, 2H), 1.70 - 1.36 (m, 3H).

[1730] The absolute stereochemistry of isomer 3 was confirmed by single crystal X-ray crystallography, now represented by the structure: having the name of ((R)-4-amino-l,3,6,7,8,9-hexahydrofuro[3,4-c]quinolin-8-yl)((4aS,10bS)- 8-(trifluoromethyl)-2,3,4,4a,6,10b-hexahydro-lH-isochromeno[4,3-b]pyridin-l- yl)methanone.

[1731] rel-((R)-4-amino-l,3,6,7,8,9-hexahydrofuro[3,4-c]quinolin-8-yl)((4aR,10bR)-8- (trifluoromethyl)-2,3,4,4a,6,10b-hexahydro-lH-isochromeno[4,3-b]pyridin-l-yl)methanone, isomer 4: MS ESI calculated for C25H26F3N3O3 [M+H]⁺, 474.19; found, 474.20. NMR (400 MHz, DMSO-d₆) 6 7.68 - 7.61 (m, 1H), 7.58 - 7.53 (m, 1H), 7.31 - 7.16 (m, 1H), 5.90

- 5.35 (m, 3H), 4.93 - 4.75 (m, 6H), 4.40 - 3.82 (m, 2H), 3.21 - 3.02 (m, 1H), 2.89 - 2.45 (m, 5H), 2.20 - 1.98 (m, 1H), 1.88 - 1.72 (m, 2H), 1.71 - 1.35 (m, 3H).

Example 9: rel-((R)-4-amino-3,6,8,9-tetrahydro-lH-furo[3,4-d]pyrano[3,4-b]pyridin-8- yl)((4aS,9bS)-7-(trifluoromethyl)-3,4,4a,9b-tetrahydrobenzofuro[3,2-b]pyridin-l(2H)- yl)methanone isomer 1

Example 10: rel-((R)-4-amino-3,6,8,9-tetrahydro- lH-furo[3,4-d]pyrano[3,4-b]pyridin-8- yl)((4aS,9bS)-7-(trifluoromethyl)-3,4,4a,9b-tetrahydrobenzofuro[3,2-b]pyridin-l(2H)- yl)methanone isomer 2

[1732] To a stirred solution of intermediate A10 isomer 2 (52 mg, 0.21 mmol) and intermediate CA3 (71 mg, 0.21 mmol) in DMF (0.5 mL) were added DIEA (82 mg, 0.64 mmol) and HATU (179 mg, 0.47 mmol) at room temperature. The mixture was stirred at room temperature for 1 h. The reaction mixture was purified directly by reverse phase flash column chromatography with 5% ~ 80% MeCN in Water (0.5% FA) to afford a 1 : 1 mixture of rel-tert-butyl ((S)-8-((4aR*,9bR*)-7-(trifluoromethyl)-l,2,3,4,4a,9b- hexahydrobenzofuro[3,2-b]pyridine-l-carbonyl)-3,6,8,9-tetrahydro-lH-furo[3,4- d]pyrano[3,4-b]pyridin-4-yl)carbamate and rel-tert-butyl ((R)-8-((4aR*,9bR*)-7- (trifluoromethyl)-l,2,3,4,4a,9b-hexahydrobenzofuro[3,2-b]pyridine-l-carbonyl)-3,6,8,9- tetrahydro-lH-furo[3,4-d]pyrano[3,4-b]pyridin-4-yl)carbamate (70 mg, 58%) as a yellow solid. MS ESI calculated for C28H30F3N3O6 [M+H]⁺, 562.21; found, 562.25.

Step 2:

[1733] A mixture of 1:1 mixture of rel-tert-butyl ((S)-8-((4aR*,9bR*)-7-(trifluoromethyl)- l,2,3,4,4a,9b-hexahydrobenzofuro[3,2-b]pyridine-l-carbonyl)-3,6,8,9-tetrahydro-lH- furo[3,4-d]pyrano[3,4-b]pyridin-4-yl)carbamate and rel-tert-butyl ((R)-8-((4aR*,9bR*)-7- (trifluoromethyl)-l,2,3,4,4a,9b-hexahydrobenzofuro[3,2-b]pyridine-l-carbonyl)-3,6,8,9- tetrahydro-lH-furo[3,4-d]pyrano[3,4-b]pyridin-4-yl)carbamate (64 mg, 0.11 mmol) in HFIP (1 mL) was stirred at 80 °C for 16 h. The reaction mixture was directly purified by reverse phase flash column chromatography with 5% ~ 80% MeCN in Water (10 mmol/L NH4HCO3) to afford a 1:1 mixture of rel-((S)-4-amino-3,6,8,9-tetrahydro-lH-furo[3,4-d]pyrano[3,4- b]pyridin-8-yl)((4aR*,9bR*)-7-(trifluoromethyl)-3,4,4a,9b-tetrahydrobenzofuro[3,2- b]pyridin-l (2H)-yl)methanone and rel-((R)-4-amino-3,6,8,9-tetrahydro-lH-furo[3,4- d]pyrano[3,4-b]pyridin-8-yl)((4aR*,9bR*)-7-(trifluoromethyl)-3,4,4a,9b- tetrahydrobenzofuro[3,2-b]pyridin-l(2H)-yl)methanone (37.4 mg, 71%) as an off-white solid. MS ESI calculated for C23H22F3N3O4 [M+H]⁺, 462.16; found, 462.15.

Step-3:

[1734] A 1:1 mixture of rel-((S)-4-amino-3,6,8,9-tetrahydro-lH-furo[3,4-d]pyrano[3,4- b]pyridin-8-yl)((4aR*,9bR*)-7-(trifluoromethyl)-3,4,4a,9b-tetrahydrobenzofuro[3,2- b]pyridin-l (2H)-yl)methanone and rel-((R)-4-amino-3,6,8,9-tetrahydro-lH-furo[3,4- d]pyrano[3,4-b]pyridin-8-yl)((4aR*,9bR*)-7-(trifluoromethyl)-3,4,4a,9b- tetrahydrobenzofuro[3,2-b]pyridin-l(2H)-yl)methanone (30 mg) was separated by Prep-chiral HPLC with the following conditions: [Column: CHIRALPAK IG, 2*25 cm, 5 pm; Mobile Phase A: Hex (0.3% IP AMIN), Mobile Phase B: MEOH: DCM=1: 1-HPLC; How rate: 20 mL/min; Gradient: 40% B to 40% B in 28 min; Wave Length: 220/254 nm; RTl(min): 9.79; RT2(min): 21.78; Sample Solvent: EtOH: DCM=1: 1— HPLC] to afford rel-((R)-4-amino- 3,6,8,9-tetrahydro-lH-furo[3,4-d]pyrano[3,4-b]pyridin-8-yl)((4aS,9bS)-7-(trifluoromethyl)- 3,4,4a,9b-tetrahydrobenzofuro[3,2-b]pyridin-l(2H)-yl)methanone isomer 1 (Example 9) (5.7 mg) as an off-white solid with retention time at 9.79 minute. MS ESI calculated for C23H22F3N3O4 [M+H]⁺, 462.16; found, 462.15. ’H NMR (400 MHz, DMSO-d₆) 87.57 - 7.18 (m, 3H), 6.21 - 6.05 (m, 1H), 5.85 (s, 2H), 5.24 - 5.07 (m, 1H), 5.03 - 4.73 (m, 4H), 4.71 - 4.61 (m, 1H), 4.58 - 4.47 (m, 1H), 4.18 - 3.81 (m, 1H), 3.09 - 2.83 (m, 2H), 2.60 - 2.54 (m, 1H), 2.50 - 2.42 (m, 1H), 1.97 - 1.70 (m, 3H), 1.69 - 1.47 (m, 1H).

[1735] The chiral resolution also afforded rel-((R)-4-amino-3,6,8,9-tetrahydro-lH-furo[3,4- d]pyrano[3,4-b]pyridin-8-yl)((4aS,9bS)-7-(trifluoromethyl)-3,4,4a,9b- tetrahydrobenzofuro[3,2-b]pyridin-l(2H)-yl)methanone isomer 2 (Example 10) (7.5 mg) as an off-white solid with retention time at 21.78 minute. MS ESI calculated for C23H22F3N3O4 [M+H]⁺, 462.16; found, 462.15. 'H NMR (400 MHz, DMSO- ₆) 87.61 - 7.20 (m, 3H), 6.15

- 5.82 (m, 3H), 5.16 - 5.08 (m, 1H), 5.03 - 4.90 (m, 2H), 4.89 - 4.78 (m, 2H), 4.78 - 4.65 (m, 1H), 4.65 - 4.53 (m, 1H), 4.18 - 3.81 (m, 1H), 3.04 - 2.75 (m, 2H), 2.55 - 2.51 (m, 1H), 2.45 - 2.30 (m, 1H), 2.01 - 1.49 (m, 4H). Example 11: rel-((S)-4-amino-l,3,6,7,8,9-hexahydrofuro[3,4-c][l,7]naphthyridin-8- yl)((4aS,9bS)-7-(trifluoromethyl)-3,4,4a,9b-tetrahydrobenzofuro[3,2-b]pyridin-l(2H)- yl)methanone isomer 1

Isomer 1

[1736] To a stirred solution of intermediate A10 isomer 2 (10 mg, 0.04 mmol), intermediate CA4 isomer 1 (13 mg, 0.04 mmol) and DIEA (16 mg, 0.12 mmol) in DMF (1 mL) was added HATU (23 mg, 0.06 mmol). The resulting mixture was stirred at room temperature for 1 h. The reaction mixture was quenched by water and was extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under vacuum to afford rel-tert-butyl (S)-4-amino- 8-((4aS,9bS)-7-(trifluoromethyl)-l,2,3,4,4a,9b-hexahydrobenzofuro[3,2-b]pyridine-l- carbonyl)-3,6,8,9-tetrahydrofuro[3,4-c][l,7]naphthyridine-7(lH)-carboxylate isomer 1 (20 mg, crude) as a yellow solid.

[1737] The crude product was dissolved in DCM (1 mL), then TFA (0.3 mL) was added. The resulting mixture was stirred at room temperature for 30 min. The mixture was concentrated under vacuum. The residue was purified by prep-HPLC with the following conditions: [Column: XBridge Prep OBD Cl 8 Column 30*150 mm; Mobile Phase A: Water (10 mmol/L NH4HCO3), Mobile Phase B: ACN; Flow rate: 60 mL/min; Gradient (B%): 5% B to 5% B in 2 min, 28% B to 48% B in 10 min; Wave Length: 254/220 nm; RTl(min): 9.2] to afford rel-((S)-4-amino- 1 ,3,6,7,8,9-hexahydrofuro[3,4-c] [ 1 ,7]naphthyridin-8- yl)((4aS,9bS)-7-(trifhioromethyl)-3,4,4a,9b-tetrahydrobenzofuro[3,2-b]pyridin-l(2H)- yl)methanone isomer 1 (Example 11) (2.4 mg, 29%) as a white solid. MS ESI calculated for C23H23F3N4O3 [M+H]⁺, 461.17; found, 461.15. 'H NMR (400 MHz, DMSO-d₆) 87.53 - 7.30 (m, 1H), 7.30 - 7.23 (m, 1H), 7.21 (s, 1H), 6.25 (m, 1H), 5.71 (s, 2H), 5.19 - 5.07 (m, 1H), 4.97 - 4.83 (m, 4H), 4.19 - 3.99 (m, 1H), 3.93 - 3.80 (m, 2H), 3.79 - 3.63 (m, 2H), 2.98 - 2.81 (m, 1H), 2.81 - 2.64 (m, 1H), 2.49 - 2.35 (m, 1H), 1.85 - 1.78 (m, 2H), 1.78 - 1.66 (m, 1H), 1.63 - 1.54 (m, 1H). Example 12: ((R)-4-amino-l,3,6,7,8,9-hexahydrofuro[3,4-c][l,7]naphthyridin-8- yl)((4aS,9bS)-7-(trifluoromethyl)-3,4,4a,9b-tetrahydrobenzofuro[3,2-b]pyridin-l(2H)- yl)methanone isomer 2

Isomer 2

[1738] To a stirred solution of intermediate A10 isomer 2 (10 mg, 0.04 mmol) and intermediate CA4 isomer 2 (14 mg, 0.04 mmol) and DIEA (16 mg, 0.12 mmol) in DMF (1 mL) was added HATU (23 mg, 0.06 mmol). The resulting mixture was stirred at room temperature for 1 h. The reaction mixture was quenched by water and was extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under vacuum to afford rel-tert-butyl (R)-4-amino- 8-((4aS,9bS)-7-(trifluoromethyl)-l,2,3,4,4a,9b-hexahydrobenzofuro[3,2-b]pyridine-l- carbonyl)-3,6,8,9-tetrahydrofuro[3,4-c][l,7]naphthyridine-7(lH)-carboxylate isomer 2 (22 mg, crude) as a yellow solid.

[1739] The crude product was dissolved in DCM (1 mL), then TFA (0.3 mL) was added. The resulting mixture was stirred at room temperature for 30 min. The mixture was concentrated under vacuum. The residue was purified by prep-HPLC with the following conditions: [Column: XBridge Prep OBD Cl 8 Column30*150 mm; Mobile Phase A: Water (10 mmol/L NH4HCO3), Mobile Phase B: ACN; Flow rate: 60 mL/min; Gradient (B%): 5% B to 5% B in 2 min, 28% B to 48% B in 10 min; Wave Length: 254/220 nm; RTl(min): 9.2] to afford rel-((R)-4-amino-l,3,6,7,8,9-hexahydrofuro[3,4-c][l,7]naphthyridin-8- yl)((4aS,9bS)-7-(trifhioromethyl)-3,4,4a,9b-tetrahydrobenzofuro[3,2-b]pyridin-l(2H)- yl)methanone isomer 2 (Example 12) (1.1 mg, 13%) as a white solid. MS ESI calculated for C23H23F3N4O3 [M+H]⁺, 461.17; found, 461.10. ’H NMR (400 MHz, DMSO-d₆) 87.68 - 7.25 (m, 2H), 7.21 (d, J = 5.4 Hz, 1H), 6.22 - 6.19 (m, 1H), 5.76 (s, 2H), 5.13 - 5.10 (m, 1H), 5.00 - 4.79 (m, 4H), 4.23 - 4.09 (m, 1H), 4.07 - 3.92 (m, 1H), 3.91 - 3.70 (m, 2H), 2.90 - 2.63 (m, 2H), 2.44 - 2.28 (m, 1H), 1.96 - 1.70 (m, 3H), 1.62 - 1.53 (m, 1H). Example 13: rel-((3R,8R)-4-amino-3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4-c]quinolin-8- yl)((4aS, 10bS)-8-(trifluoromethyl)-2,3,4,4a,6, 1 Ob-hexahydro- 1 H-isochromeno[4,3-b]pyridin- l-yl)methanone isomer 1

Isomer 1

[1740] A mixture of intermediate CA5 isomer 1 (46 mg, 0.18 mmol), intermediate A2 isomer 1 (40 mg, 0.15 mmol), TBTU (99 mg, 0.31 mmol) and EtsN (125 mg, 1.24 mmol) in DMF (2 mL) was stirred at room temperature for 16 h. The reaction mixture was quenched with water and extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered and concentrated under reduced pressure. The residue was purified by Prep-HPLC with the following conditions: [Column: XBridge Prep OBD C18 Column, 30*150 mm, 5pm; Mobile Phase A: Water (10 mmol/L NH4HCO3), Mobile Phase B: ACN; Flow rate: 60 mL/min; Gradient: 36% B to 46% B in 12 min; Wave Length: 254/220 nm; RTl(min): 10.23] to afford rel-((3R,8R)-4-amino-3-methyl-l,3,6,7,8,9- hexahydrofuro[3,4-c]quinolin-8-yl)((4aS,10bS)-8-(trifluoromethyl)-2,3,4,4a,6,10b- hexahydro-lH-isochromeno[4,3-b]pyridin-l-yl)methanone isomer 1 (Example 13) (25.2 mg, 33%) as an off-white solid. MS ESI calculated for C26H28F3N3O3 [M+H]⁺, 488.21; found, 488.25. NMR (400 MHz, DMSO-d₆) 8 (ppm) 7.77 - 7.48 (m, 2H), 7.32 - 7.15 (m, 1H), 5.91 - 5.37 (m, 3H), 5.33 - 5.15 (m, 1H), 5.02 - 4.66 (m, 4H), 4.42 - 3.81 (m, 2H), 3.24 - 3.06 (m, 1H), 2.90 - 2.43 (m, 5H), 2.18 - 1.95 (m, 1H), 1.92 - 1.74 (m, 2H), 1.72 - 1.60 (m, 2H), 1.59 - 1.47 (m, 1H), 1.44 - 1.22 (m, 3H).

Example 14: rel-((3R,8R)-4-amino-3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4-c]quinolin-8- yl)((4aS,10bS)-8-(trifluoromethyl)-2,3,4,4a,6,10b-hexahydro-lH-isochromeno[4,3-b]pyridin- l-yl)methanone isomer 2

Isomer 2

[1741] To a solution of intermediate CA5 isomer 2 (40 mg, 0.16 mmol) in DMF (4 mL) were added TEA (130 mg, 1.29 mmol), TBTU (103 mg, 0.32 mmol) and intermediate A2 isomer 1 (41 mg, 0.16 mmol) at room temperature. The mixture was stirred at room temperature for 2 h. The reaction mixture was quenched with water and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered and concentrated under vacuum. The crude product was purified by Prep- HPLC with the following conditions: (Column: XBridge Prep OBD C18 Column, 30*150 mm, 5pm; Mobile Phase A: Water (10 mmol/L NH4HCO3), Mobile Phase B: ACN; Flow rate: 60 mL/min; Gradient (B%): 38% B to 48% B in 12 min; Wave Length: 254/220 nm; RTl(min): 10.23) to afford rel-((3R,8R)-4-amino-3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4- c]quinolin-8-yl)((4aS, 10bS)-8-(trifhioromethyl)-2,3,4,4a,6, 1 Ob-hexahydro- 1H- isochromeno[4,3-b]pyridin-l-yl)methanone isomer 2 (Example 14) (17.2 mg, 21%) as a white solid. MS ESI calculated for C26H28F3N3O3 [M+H]⁺, 488.21; found, 488.25. 'H NMR (400 MHz, DMSO-ffc) 5 (ppm) 7.70 - 7.50 (m, 2H), 7.33 - 7.16 (m, 1H), 5.87 - 5.38 (m, 3H), 5.26 - 5.18 (m, 1H), 4.98 - 4.74 (m, 4H), 4.39 - 3.80 (m, 2H), 3.20 - 3.09 (m, 1H), 2.87 - 2.54 (m, 5H), 2.16 - 1.92 (m, 1H), 1.91 - 1.73 (m, 2H), 1.72 - 1.47 (m, 3H), 1.37 - 1.30 (m, 3H).

Example 15: rel-((3R,8R)-4-amino-3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4-c]quinolin-8- yl)((4aS,10bS)-8-(trifluoromethyl)-2,3,4,4a,6,10b-hexahydro-lH-isochromeno[4,3-b]pyridin- l-yl)methanone isomer 3

Isomer 3

[1742] To a stirred solution of intermediate CA5 isomer 3 (46 mg, 0.18 mmol) and intermediate A2 isomer 1 (40 mg, 0.16 mmol) in DMF (2 mL) were added TBTU (100 mg, 0.31 mmol) and EtsN (126 mg, 1.24 mmol) at room temperature. The resulting mixture was stirred at room temperature for Ih. The reaction mixture was quenched with water and extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered and concentrated under reduced pressure. The residue was purified by Prep-HPLC with the following conditions: [Column: XBridge Prep OBD Cl 8 Column, 30*150 mm, 5pm; Mobile Phase A: Water (10 mmol/L NH4HCO3), Mobile Phase B: ACN; Flow rate: 60 mL/min; Gradient: 35% B to 50% B in 12 min; Wave Length: 254/220 nm; RTl(min): 7.5] to afford rel-((3R,8R)-4-amino-3-methyl-l,3,6,7,8,9- hexahydrofuro[3,4-c]quinolin-8-yl)((4aS,10bS)-8-(trifluoromethyl)-2,3,4,4a,6,10b- hexahydro- lH-isochromeno[4,3-b]pyridin-l-yl)methanone isomer 3 (Example 15) (22.4 mg, 29%) as an off-white solid. MS ESI calculated for C26H28F3N3O3 [M+H]⁺, 488.21; found, 488.25. 'H NMR (400 MHz, DMSO-d₆) 8 (ppm) 7.70 - 7.50 (m, 2H), 7.31 - 7.15 (m, IH), 5.95 - 5.36 (m, 3H), 5.26 - 5.17 (m, IH), 4.99 - 4.67 (m, 4H), 4.42 - 3.81 (m, 2H), 3.20 - 3.04 (m, IH), 2.91 - 2.44 (m, 5H), 2.16 - 1.96 (m, IH), 1.91 - 1.50 (m, 5H), 1.40 - 1.22 (m, 3H).

Example 16: rel-((3R,8R)-4-amino-3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4-c]quinolin-8- yl)((4aS,10bS)-8-(trifluoromethyl)-2,3,4,4a,6,10b-hexahydro-lH-isochromeno[4,3-b]pyridin- l-yl)methanone isomer 4

Isomer 4

[1743] A mixture of intermediate CA5 isomer 4 (46 mg, 0.19 mmol), intermediate A2 isomer 1 (40 mg, 0.16 mmol), TBTU (100 mg, 0.31 mmol) and TEA (126 mg, 1.24 mmol) in DMF (2 mL) was stirred at room temperature for 16 h. The reaction mixture was quenched with water and extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered and concentrated under reduced pressure. The residue was purified by Prep-HPLC with the following conditions: [Column: XSelect CSH Prep C18 OBD Column, 19*250 mm, 5pm; Mobile Phase A: Water (10 mmol/L NH4HCO3), Mobile Phase B: ACN; Flow rate: 20 mL/min; Gradient: 35% B to 45% B in 10 min, 45% B to 45% B in 20 min; Wave Length: 254/220 nm; RTl(min): 14.9] to afford rel-((3R,8R)-4- amino-3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4-c]quinolin-8-yl)((4aS,10bS)-8- (trifhioromethyl)-2,3,4,4a,6, 1 Ob-hexahydro- 1 H-isochromeno [4,3-b]pyridin- 1 -yl)methanone isomer 4 (Example 16) (22.4 mg, 29%) as a white solid. MS ESI calculated for C26H28F3N3O3 [M+H]⁺, 488.21; found, 488.20. ’H NMR (400 MHz, DMSO-d₆) 8 (ppm) 7.73 - 7.49 (m, 2H), 7.34 - 7.17 (m, 1H), 5.90 - 5.38 (m, 3H), 5.27 - 5.18 (m, 1H), 5.01 - 4.69 (m, 4H), 4.41 - 3.82 (m, 2H), 3.22 - 3.12 (m, 1H), 2.86 - 2.53 (m, 5H), 2.16 - 1.94 (m, 1H), 1.90 - 1.73 (m, 2H), 1.72 - 1.47 (m, 3H), 1.45 - 1.23 (m, 3H).

Example 17: rel-((R)-4-amino-3,6,8,9-tetrahydro-lH-furo[3,4-d]pyrano[3,4-b]pyridin-8- yl)((4aS,10bS)-8-(trifluoromethyl)-2,3,4,4a,6,10b-hexahydro-lH-isochromeno[4,3-b]pyridin- l-yl)methanone Step 1:

[1744] To a solution of intermediate CA3 isomer 1 (60 mg, 0.18 mmol) and intermediate A2 isomer 1 (46 mg, 0.18 mmol) in DMF (3 mL) were sequentially added DIEA (115 mg, 0.89 mmol) and HATU (136 mg, 0.36 mmol) at room temperature. The resulting solution was stirred at room temperature for 2 h. The reaction mixture was directly purified by reverse phase flash column chromatography with 5% ~ 100% MeCN in Water (10 mmol/L NH4HCO3) to afford rel-tert-butyl ((R)-8-((4aS,10bS)-8-(trifluoromethyl)-2,3,4,4a,6,10b- hexahydro-lH-isochromeno[4,3-b]pyridine-l-carbonyl)-3,6,8,9-tetrahydro-lH-furo[3,4- d]pyrano[3,4-b]pyridin-4-yl)carbamate (25 mg, 24%) as a colorless semi-solid. MS ESI calculated for C29H32F3N3O6 [M+H]⁺, 576.22; found, 576.25.

Step 2:

[1745] A mixture of rel-tert-butyl ((R)-8-((4aS,10bS)-8-(trifluoromethyl)-2,3,4,4a,6,10b- hexahydro-lH-isochromeno[4,3-b]pyridine-l-carbonyl)-3,6,8,9-tetrahydro-lH-furo[3,4- d]pyrano[3,4-b]pyridin-4-yl)carbamate (25 mg, 0.04 mmol) in HFIP (2 mL) was stirred at 80 °C for 16 h. The resulting mixture was concentrated under reduced pressure. The residue was purified by Prep-HPLC with the following conditions: [Column: XBridge Prep Phenyl OBD Column 19*250 mm, 5 m; Mobile Phase A: Water (10 mmol/L NH4HCO3), Mobile Phase B: ACN; Flow rate: 20 mL/min; Gradient: 30% B to 40% B in 10 min, 40% B to 40% B in 20 min; Wave Length: 254/220 rnn; RTl(min): 15.3] to afford rel-((R)-4-amino-3,6,8,9- tetrahydro-lH-furo[3,4-d]pyrano[3,4-b]pyridin-8-yl)((4aS,10bS)-8-(trifluoromethyl)- 2,3,4,4a,6,10b-hexahydro-lH-isochromeno[4,3-b]pyridin-l-yl)methanone (Example 17) (8.1 mg, 39%) as a white solid. MS ESI calculated for C24H24F3N3O4 [M+H]⁺, 476.17; found, 476.20. NMR (400 MHz, DMSO-d₆) 8 (ppm) 7.73 - 7.14 (m, 3H), 5.92 - 5.41 (m, 3H), 5.04 - 4.47 (m, 9H), 4.31 - 3.82 (m, 2H), 3.07 - 2.98 (m, 1H), 2.68 - 2.44 (m, 2H), 1.84 - 1.74 (m, 1H), 1.73 - 1.33 (m, 3H).

[1746] Based on the absolute stereochemistry of CA3 isomer 1, Example 17 is now represented by the structure:

Example 18: rel-((3R*,8R*)-4-amino-3-methyl- 1 ,3,6,7,8,9-hexahydrofuro[3,4- c] [ 1 ,7]naphthyridin-8-yl)((4aS, 10bS)-8-(difluoromethoxy)-2,3,4,4a,6, 1 Ob-hexahydro- 1 H- pyrano[3,2-b:5,4-b']dipyridin-l-yl)methanone isomer 1

Step 1:

[1747] To a stirred solution of intermediate A19 (60 mg, 0.23 mmol) and intermediate CA6 isomer 1 (90 mg, 0.26 mmol) in DMF (10 mL) were added DIEA (121 mg, 0.94 mmol) and HATU (133 mg, 0.35 mmol) at room temperature. The resulting mixture was stirred at room temperature for 16 h. The reaction mixture was quenched with water and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered and concentrated under reduced pressure. The residue was purified by flash column chromatography with 0 ~ 50% ethyl acetate in petroleum ether to afford rel-tert-butyl (3R*,8R*)-4-amino-8-((4aS, 10bS)-8-(difluoromethoxy)-2,3,4,4a,6, 1 Ob-hexahydro- 1 H- pyrano[3,2-b:5,4-b']dipyridine-l-carbonyl)-3-methyl-3,6,8,9-tetrahydrofuro[3,4- c][l,7]naphthyridine-7(lH)-carboxylate isomer 1 (120 mg, 87%) as a yellow semi-solid. MS ESI calculated for C29H35F2N5O6 [M+H]⁺, 588.26; found, 588.30.

Step 2:

[1748] A mixture of rel-tert-butyl (3R*,8R*)-4-amino-8-((4aS,10bS)-8-(difluoromethoxy)- 2,3,4,4a,6,10b-hexahydro-lH-pyrano[3,2-b:5,4-b']dipyridine-l-carbonyl)-3-methyl-3,6,8,9- tetrahydrofuro[3,4-c][l,7]naphthyridine-7(lH)-carboxylate isomer 1 (120 mg, 0.20 mmol) and hydrogen chloride (3 mL, 4.0 M in ethyl acetate) was stirred at room temperature forl6 h. The reaction mixture was concentrated under reduced pressure. The residue was purified by Prep-HPLC with the following conditions: [Column: XSelect CSH Prep C18 OBD Column, 19*250 mm; Mobile Phase A: Water (0.05% HC1), Mobile Phase B: ACN; Flow rate: 25 mL/min; Gradient: 10% B to 20% B in 10 min; Wave Length: 254/220 nm; RTl(min): 9.2] to affordrel-((3R*,8R*)-4-amino-3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4- c][l,7]naphthyridin-8-yl)((4aS,10bS)-8-(difluoromethoxy)-2,3,4,4a,6,10b-hexahydro-lH- pyrano[3,2-b:5,4-b']dipyridin-l-yl)methanone isomer 1 (Example 18) (52.4 mg, 48%) as a yellow solid. MS ESI calculated for C24H27F2N5O4 [M+H]⁺, 488.20; found, 488.25. 'H NMR (400 MHz, DMSO-6?6 + D₂O) 5 (ppm) 8.11 - 7.42 (m, 2H), 7.05 (d, J = 8.4 Hz, 1H), 5.77 - 5.34 (m, 2H), 5.28 - 5.01 (m, 2H), 4.92 - 4.54 (m, 3H), 4.47 - 4.05 (m, 3H), 3.70 - 3.62 (m, 2H), 3.14 - 3.03 (m, 1H), 2.94 - 2.72 (m, 2H), 2.25 - 1.60 (m, 4H), 1.48 - 1.32 (m, 3H).

Example 19: rel-((3R*,8R*)-4-amino-3-methyl- 1 ,3,6,7,8,9-hexahydrofuro[3,4- c] [l,7]naphthyridin-8-yl)((4aS, 10bS)-8-(difluoromethoxy)-2,3,4,4a,6, 1 Ob-hexahydro- 1H- pyrano[3,2-b:5,4-b']dipyridin-l-yl)methanone isomer 2

Step-1: [1749] To a stirred mixture of intermediate CA6 isomer 2 (70 mg, 0.200 mmol) and intermediate A19 (47 mg, 0.18 mmol) in N,N-dimethylacetamide (10 mL) were added bis(2- oxo-l,3-oxazolidin-3-yl)phosphinoyl chloride (60 mg, 0.24 mmol) and EtaN (55 mg, 0.55 mmol). The resulting mixture was stirred at room temperature for 1 h. The resulting mixture was quenched with water and extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous NaiSO4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by reversed-phase flash chromatography with the following conditions: column, Cl 8 silica gel; mobile phase, MeCN in Water (10 mmol/L NH4HCO3), 5% to 95% gradient in 30 min to afford rel- tert-butyl (3R*,8R*)-4-amino-8-((4aS, 10bS)-8-(difluoromethoxy)-2,3,4,4a,6, lOb-hexahydro- lH-pyrano[3,2-b:5,4-b']dipyridine-l-carbonyl)-3-methyl-3,6,8,9-tetrahydrofuro[3,4- c][l,7]naphthyridine-7(lH)-carboxylate isomer 2 (15 mg, 14%) as a white solid. MS ESI calculated for C29H35F2N5O6 [M+H]⁺, 588.26; found, 588.30.

Step-2: somer

[1750] A mixture of rel-tert-butyl (3R*,8R*)-4-amino-8-((4aS,10bS)-8-(difluoromethoxy)- 2,3,4,4a,6,10b-hexahydro-lH-pyrano[3,2-b:5,4-b']dipyridine-l-carbonyl)-3-methyl-3,6,8,9- tetrahydrofuro[3,4-c][l,7]naphthyridine-7(lH)-carboxylate isomer 2 (15 mg, 0.026 mmol) and HC1 (4.0 M in ethyl acetate) (1 mL) was stirred at room temperature for 1 h. The resulting mixture was concentrated under reduced pressure. The residue was purified by reversed-phase flash chromatography with 5% to 80% MeCN in Water (10 mmol/L NH4HCO3) to afford rel-((3R*,8R*)-4-amino-3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4- c][l,7]naphthyridin-8-yl)((4aS,10bS)-8-(difluoromethoxy)-2,3,4,4a,6,10b-hexahydro-lH- pyrano[3,2-b:5,4-b']dipyridin-l-yl)methanone isomer 2 (Example 19) (1.5 mg, 12%) as a white solid. MS ESI calculated for C24H27F2N5O4 [M+H]⁺, 488.20; found, 488.20. ^JH NMR (400 MHz, DMSO-de) 5 8.11 - 7.36 (m, 2H), 7.01 (dd, J= 8.4, 4.4 Hz, 1H), 5.93 - 5.42 (m, 3H), 5.23 - 5.19 (m, 1H), 5.00 - 4.85 (m, 1H), 4.82 - 4.49 (m, 3H), 4.28 - 3.63 (m, 5H), 2.95

- 2.76 (m, 1H), 2.71 - 2.54 (m, 1H), 2.48 - 2.33 (m, 2H), 1.79 - 1.45 (m, 4H), 1.35 - 1.27 (m, 3H).

Example 20: ((3R,8R)-4-amino-3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4-c][l,7]naphthyridin-

8-yl)((4aS,10bS)-8-(difluoromethoxy)-2,3,4,4a,6,10b-hexahydro-lH-pyrano[3,2-b:5,4- b']dipyridin-l-yl)methanone isomer 3

Step-1:

[1751] A solution of intermediate CA6 isomer 3 (100 mg, 0.29 mmol) and intermediate A19 (67 mg, 0.26 mmol) in DMF (10 mL) was treated with DIEA (101 mg, 0.78 mmol) at room temperature for 5 min followed by the addition of HATU (199 mg, 0.52 mmol) at room temperature. The resulting mixture was stirred at room temperature for 1 h. The reaction was quenched with water and extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SO4. After filtration, the filtrate was concentrated under reduced pressure. The residue was dissolved in DMF (2 mL) and was purified by prep-HPLC with the following conditions: [Column: XBridge Prep OBD C18 Column, 30*150 mm, 5 pm; Mobile Phase A: Water (10 mmol/L NH4HCO3), Mobile Phase B: ACN; Flow rate: 60 mL/min; Gradient: 39B to 59B in 10 min; Wave Length: 254/220 nm; RTl(min): 8.9) to afford tert-butyl (3R,8R)-4-amino-8-((4aS, 10bS)-8-(difluoromethoxy)-2,3,4,4a,6, 10b- hexahydro- lH-pyrano[3,2-b:5,4-b']dipyridine- 1 -carbonyl)-3-methyl-3, 6,8,9- tetrahydrofuro[3,4-c][l,7]naphthyridine-7(lH)-carboxylate isomer 3 (35 mg, 22%) as a white solid. MS ESI calculated for C29H35F2N5O6 [M+H]⁺, 588.26; found, 588.30.

Step-2:

[1752] The product of tert-butyl (3R,8R)-4-amino-8-((4aS,10bS)-8-(difluoromethoxy)- 2,3,4,4a,6,10b-hexahydro-lH-pyrano[3,2-b:5,4-b']dipyridine-l-carbonyl)-3-methyl-3,6,8,9- tetrahydrofuro[3,4-c][l,7]naphthyridine-7(lH)-carboxylate isomer 3 (35 mg, 0.060 mmol) was dissolved in HC1 (4.0 M in ethyl acetate) (1 mL), and then the mixture was stirred at room temperature for 1 h. The resulting mixture was concentrated under reduced pressure. The residue was purified by reversed-phase flash chromatography with the following conditions: [column, C18 silica gel; mobile phase, MeCN in Water (10 mmol/L NH4HCO3), 5% to 50% gradient in 30 min] to afford ((3R,8R)-4-amino-3-methyl-l,3,6,7,8,9- hexahydrofuro[3,4-c][l,7]naphthyridin-8-yl)((4aS,10bS)-8-(difluoromethoxy)-2,3,4,4a,6,10b- hexahydro-lH-pyrano[3,2-b:5,4-b']dipyridin-l-yl)methanone isomer 3 (Example 20) (27.3 mg, 94%) as a white solid. MS ESI calculated for C24H27F2N5O4 [M+H]⁺, 488.20 found, 488.20. ’H NMR (400 MHz, DMSO-d₆) 87.97 - 7.35 (m, 2H), 7.15 - 6.90 (m, 1H), 5.93 - 5.39 (m, 3H), 5.24 (d, J = 7.2 Hz, 1H), 5.04 - 4.89 (m, 1H), 4.87 - 4.76 (m, 1H), 4.74 - 4.65 (m, 1H), 4.64 - 4.56 (m, 1H), 4.33 - 4.13 (m, 1H), 4.11 - 3.89 (m, 2H), 3.83 - 3.57 (m, 2H), 2.81 - 2.64 (m, 1H), 2.63 - 2.54 (m, 1H), 2.49 - 2.43 (m, 1H), 2.15 - 1.55 (m, 4H), 1.37 - 1.27 (m, 3H).

Example 21: rel-((3R*,8R*)-4-amino-3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4- c] [ 1 ,7]naphthyridin-8-yl)((4aS, 10bS)-8-(difluoromethoxy)-2,3,4,4a,6, 1 Ob-hexahydro- 1H- pyrano[3,2-b:5,4-b']dipyridin-l-yl)methanone isomer 4

Step-1:

[1753] To a stirred solution of intermediate A19 (60 mg, 0.24 mmol) and intermediate CA6 isomer 4 (90 mg, 0.26 mmol) in DMF (9 mL) were added DIEA (121 mg, 0.94 mmol) and HATU (134 mg, 0.35 mmol). The resulting mixture was stirred at room temperature for 1 h. The reaction was quenched with water and extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SC>4. After filtration, the filtrate was concentrated under reduced pressure. The resulting residue was purified by Combi Flash (Biotage Isolera Prime) which applied to a 25 g silica gel column that was eluted with 0-90% ethyl acetate in petroleum ether within 30 min to afford rel-tert-butyl (3R*,8R*)-4-amino-8- ((4aS,10bS)-8-(difluoromethoxy)-2,3,4,4a,6,10b-hexahydro-lH-pyrano[3,2-b:5,4- b']dipyridine-l -carbonyl)-3-methyl-3,6,8,9-tetrahydrofuro[3,4-c] [1 ,7]naphthyridine-7(lH)- carboxylate isomer 4 (70 mg, 50%) as a colorless oil. MS ESI calculated for C29H35F2N5O6 [M+H]⁺, 588.26; found, 588.30.

Step-2:

[1754] A mixture of rel-tert-butyl (3R*,8R*)-4-amino-8-((4aS,10bS)-8-(difluoromethoxy)- 2,3,4,4a,6,10b-hexahydro-lH-pyrano[3,2-b:5,4-b']dipyridine-l-carbonyl)-3-methyl-3,6,8,9- tetrahydrofuro[3,4-c][l,7]naphthyridine-7(lH)-carboxylate isomer 4 (65 mg, 0.11 mmol) and hydrogen chloride (4.0 M in ethyl acetate) (2 mL) and then was stirred at room temperature for 1 h. The resulting mixture was concentrated under vacuum. The resulting residue was purified by Combi Flash (Biotage Isolera Prime) with a 25 g C18 column, eluted with 5-45% acetonitrile in water to afford rel-((3R*,8R*)-4-amino-3-methyl-l,3,6,7,8,9- hexahydrofuro[3,4-c][l,7]naphthyridin-8-yl)((4aS,10bS)-8-(difluoromethoxy)-2,3,4,4a,6,10b- hexahydro-lH-pyrano[3,2-b:5,4-b']dipyridin-l-yl)methanone isomer 4 (Example 21) (23.2 mg, 43%) as a white solid. MS ESI calculated for C24H27F2N5O4 [M+H]⁺, 488.20; found, 488.20. ¹H NMR (400 MHz, DMSO-d₆) 5 8.06 - 7.32 (m, 2H), 7.11 - 6.86 (m, 1H), 5.94 - 5.68 (m, 1H), 5.66 - 5.53 (m, 2H), 5.23 (d, J = 6.0 Hz, 1H), 5.01 - 4.53 (m, 4H), 4.33 - 4.01 (m, 1H), 4.00 - 3.58 (m, 4H), 3.01 - 2.72 (m, 1H), 2.70 - 2.52 (m, 1H), 2.46 - 2.38 (m, 1H), 2.15 - 1.46 (m, 4H), 1.40 - 1.29 (m, 3H).

Example 22: rel-((3R*,8R*)-4-amino-3-methyl-3,6,8,9-tetrahydro-lH-furo[3,4- d]pyrano[3,4-b]pyridin-8-yl)((4aS,10bS)-8-(difluoromethoxy)-2,3,4,4a,6,10b-hexahydro-lH- pyrano[3,2-b:5,4-b']dipyridin-l-yl)methanone isomer 1 Example 23: rel-((3R*,8R*)-4-amino-3-methyl-3,6,8,9-tetrahydro-lH-furo[3,4- d]pyrano[3,4-b]pyridin-8-yl)((4aS,10bS)-8-(difluoromethoxy)-2,3,4,4a,6,10b-hexahydro-lH- pyrano[3,2-b:5,4-b']dipyridin-l-yl)methanone isomer 2

Example 24: rel-((3R*,8R*)-4-amino-3-methyl-3,6,8,9-tetrahydro-lH-furo[3,4- d]pyrano[3,4-b]pyridin-8-yl)((4aS,10bS)-8-(difluoromethoxy)-2,3,4,4a,6,10b-hexahydro-lH- pyrano[3,2-b:5,4-b']dipyridin-l-yl)methanone isomer 3

Example 25: rel-((3R*,8R*)-4-amino-3-methyl-3,6,8,9-tetrahydro-lH-furo[3,4- d]pyrano[3,4-b]pyridin-8-yl)((4aS,10bS)-8-(difluoromethoxy)-2,3,4,4a,6,10b-hexahydro-lH- pyrano[3,2-b:5,4-b']dipyridin-l-yl)methanone isomer 4 [1755] To a stirred mixture of 1:8 mixture of intermediate CA7 and intermediate CA8 (100 mg, 0.26 mmol) and intermediate Al 9 (73 mg, 0.26 mmol) in DMAc (5 mL) were added DIEA (111 mg, 0.86 mmol) and HATU (163 mg, 0.43 mmol) at room temperature under nitrogen atmosphere. The resulting mixture was stirred at room temperature for 2 h. The resulting mixture was quenched with water and extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous NaiSt After filtration, the filtrate was concentrated under reduced pressure. The filtrate was concentrated under reduced pressure. The resulting residue was purified by silica gel column chromatography, eluted with 0-65% EtOAc in petroleum ether to afford a 1:8 mixture of tert-butyl (8-((4aS,10bS)-8- (difluoromethoxy)-2,3,4,4a,6,10b-hexahydro-lH-pyrano[3,2-b:5,4-b']dipyridine-l-carbonyl)- 3-methyl-3,6,8,9-tetrahydro-lH-furo[3,4-d]pyrano[3,4-b]pyridin-4-yl)carbamate and tertbutyl (8-((4aS,10bS)-8-(difluoromethoxy)-2,3,4,4a,6,10b-hexahydro-lH-pyrano[3,2-b:5,4- b']dipyridine-l-carbonyl)-l-methyl-3,6,8,9-tetrahydro-lH-furo[3,4-d]pyrano[3,4-b]pyridin-4- yl)carbamate (60 mg, 65%) as a white solid. MS ESI calculated for C29H34F2N4O7 [M+H]⁺, 589.24; found, 589.20.

Step-2:

[1756] To a stirred solution of 1:8 mixture of tert-butyl (8-((4aS,10bS)-8- (difluoromethoxy)-2,3,4,4a,6,10b-hexahydro-lH-pyrano[3,2-b:5,4-b']dipyridine-l-carbonyl)- 3-methyl-3,6,8,9-tetrahydro-lH-furo[3,4-d]pyrano[3,4-b]pyridin-4-yl)carbamate and tertbutyl (8-((4aS,10bS)-8-(difluoromethoxy)-2,3,4,4a,6,10b-hexahydro-lH-pyrano[3,2-b:5,4- b']dipyridine-l-carbonyl)-l-methyl-3,6,8,9-tetrahydro-lH-furo[3,4-d]pyrano[3,4-b]pyridin-4- yl)carbamate (400 mg, 0.68 mmol) in DCM (5 mL) was added HC1 (5 mL, 4 M in 1,4- dioxane). The resulting mixture was stirred at room temperature for 16 h. The reaction solution was concentrated under vacuum to afford a 1:8 mixture of (4-amino-3-methyl- 3,6,8,9-tetrahydro-lH-furo[3,4-d]pyrano[3,4-b]pyridin-8-yl)((4aS,10bS)-8- (difluoromethoxy)-2,3,4,4a,6,10b-hexahydro-lH-pyrano[3,2-b:5,4-b']dipyridin-l- yl)methanone and (4-amino-l-methyl-3,6,8,9-tetrahydro-lH-furo[3,4-d]pyrano[3,4- b]pyridin-8-yl)((4aS,10bS)-8-(difluoromethoxy)-2,3,4,4a,6,10b-hexahydro-lH-pyrano[3,2- b:5,4-b']dipyridin-l-yl)methanone (350 mg, crude) as a white solid. MS ESI calculated for C24H26F2N4O5 [M+H]⁺, 489.19; found, 489.25.

[1757] The 1:8 mixture of (4-amino-3-methyl-3,6,8,9-tetrahydro-lH-furo[3,4- d]pyrano[3,4-b]pyridin-8-yl)((4aS,10bS)-8-(difluoromethoxy)-2,3,4,4a,6,10b-hexahydro-lH- pyrano[3,2-b:5,4-b']dipyridin- 1 -yl)methanone and (4-amino- 1 -methyl-3,6,8,9-tetrahydro-lH- furo[3,4-d]pyrano[3,4-b]pyridin-8-yl)((4aS,10bS)-8-(difhioromethoxy)-2,3,4,4a,6,10b- hexahydro-lH-pyrano[3,2-b:5,4-b']dipyridin-l-yl)methanone (430 mg) was separated by Prep-Chiral HPLC with the following conditions: [Column: CHIRALPAK IE, 2*25 cm, 5 pm; Mobile Phase A: Hex (0.5% 2 M NH₃-MeOH), Mobile Phase B: MeOH: DCM=1: 1- HPLC; Flow rate: 20 mL/min; Gradient (B%): 50% B to 50% B in 31 min; Wave Length: 220/254 nm; RTl(min): 8.85; RT2(min): 9.54; RT3 (min): 10.29; RT4 (min): 21.08; RT5 (min): 25.24; Sample Solvent: MeOH: EtOH=l: 1— HPLC] to afford fraction A (50 mg) as the first eluting peak, fraction B (65 mg) as the second eluting peak, fraction C (75 mg) as the third eluting peak, fraction D (39.5 mg) as the fourth eluting peak and fraction E (18 mg) as the fifth eluting peak.

[1758] The fraction B was further separated by Prep-Chiral HPLC with following condition: [Column: CHIRALPAK IF, 2*25 cm, 5 pm; Mobile Phase A: Hex (0.5% 2 M NHs-MeOH), Mobile Phase B: MeOH: DCM=1 : 1— HPLC; Flow rate: 20 mL/min; Gradient (B%): 40% B to 40% B in 27 min; Wave Length: 220/254 nm; RT1 (min): 10.70; RT2 (min): 12.39; Sample Solvent: MeOH: EtOH=l: 1-HPLC] to afford rel-((3R*,8R*)-4-amino-3- methyl-3,6,8,9-tetrahydro-lH-furo[3,4-d]pyrano[3,4-b]pyridin-8-yl)((4aS,10bS)-8- (difluoromethoxy)-2,3,4,4a,6,10b-hexahydro-lH-pyrano[3,2-b:5,4-b']dipyridin-l- yl)methanone isomer 1 (Example 22) (1.9 mg, 0.4%) as a white solid with retention time at

12.39 minute. MS ESI calculated for C24H26F2N4O5 [M+H]⁺, 489.19; found, 489.15. 'H NMR (400 MHz, CD3OD) 57.81 - 7.30 (m, 2H), 6.99 - 6.85 (m, 1H), 6.00 - 5.51 (m, 1H), 5.43 - 5.28 (m, 1H), 5.14 - 5.05 (m, 1H), 5.04 - 4.94 (m, 1H), 4.85 - 4.80 (m, 1H), 4.80 - 4.71 (m, 2H), 4.71 - 4.58 (m, 2H), 4.42 - 3.78 (m, 2H), 3.18 - 3.04 (m, 1H), 2.89 - 2.77 (m, 1H), 2.71

- 2.51 (m, 1H), 1.98 - 1.78 (m, 3H), 1.76 - 1.57 (m, 1H), 1.49 - 1.41 (m, 3H).

[1759] The fraction C was further separated by Prep-Chiral HPLC with following condition [Column: CHIRALPAK IF, 2*25 cm, 5 pm; Mobile Phase A: Hex(0.5% 2M NH₃-MeOH), Mobile Phase B: MEOH: DCM=1: 1— HPLC; Flow rate: 20 mL/min; Gradient (B%): 40% B to 40% B in 30 min; Wave Length: 220/254 nm; RTl(min): 15.77; RT2(min): 23.84;

RT3(min): 25.64. Sample Solvent: MeOH: EtOH=l: 1-HPLC] to affordrel-((3R*,8R*)-4- amino-3-methyl-3,6,8,9-tetrahydro-lH-furo[3,4-d]pyrano[3,4-b]pyridin-8-yl)((4aS,10bS)-8- (difhioromethoxy)-2,3,4,4a,6,10b-hexahydro-lH-pyrano[3,2-b:5,4-b']dipyridin-l- yl)methanone isomer 2 (Example 23) (4.1 mg, 0.9%) as a white solid with the retention time at 15.77 minute. MS ESI calculated for C24H26F2N4O5 [M+H]⁺, 489.19; found, 489.15. 'H NMR (400 MHz, CD3OD) 57.87 - 7.29 (m, 2H), 6.98 - 6.83 (m, 1H), 5.91 - 5.39 (m, 1H),

5.39 - 5.29 (m, 1H), 5.14 - 5.04 (m, 1H), 5.03 - 4.95 (m, 1H), 4.85 - 4.81 (m, 1H), 4.80 - 4.73 (m, 2H), 4.73 - 4.66 (m, 1H), 4.66 - 4.55 (m, 1H), 4.55 - 3.79 (m, 2H), 3.17 - 2.99 (m, 1H), 2.90 - 2.14 (m, 2H), 1.97 - 1.51 (m, 4H), 1.50 - 1.40 (m, 3H).

[1760] This chiral resolution of fraction C also afforded rel-((3R*,8R*)-4-amino-3-methyl- 3,6,8,9-tetrahydro-lH-furo[3,4-d]pyrano[3,4-b]pyridin-8-yl)((4aS,10bS)-8- (difluoromethoxy)-2,3,4,4a,6,10b-hexahydro-lH-pyrano[3,2-b:5,4-b']dipyridin-l- yl)methanone isomer 3 (Example 24) (3.2 mg, 0.7%) as a white solid with retention time at 25.64 minute. MS ESI calculated for C24H26F2N4O5 [M+H]⁺, 489.19; found, 489.20. 'H NMR (400 MHz, CD3OD) 37.77 - 7.29 (m, 2H), 6.97 - 6.85 (m, 1H), 5.97 - 5.50 (m, 1H), 5.41 - 5.30 (m, 1H), 5.17 - 5.03 (m, 1H), 5.00 - 4.92 (m, 2H), 4.82 - 4.70 (m, 3H), 4.71 - 4.59 (m, 1H), 4.23 - 3.81 (m, 2H), 3.18 - 2.03 (m, 1H), 2.92 - 2.76 (m, 1H), 2.72 - 2.53 (m, 1H), 1.97

- 1.76 (m, 3H), 1.76 - 1.50 (m, 1H), 1.50 - 1.38 (m, 3H).

[1761] The fraction E was further purified by Prep-Chiral HPLC with following condition: [Column: Lux 5um Celhilose-4, 2.12*25 cm, 5 pm; Mobile Phase A: Hex (0.5% 2M NH3- MeOH), Mobile Phase B: EtOH: MeOH=l: 1— HPLC; Flow rate: 20 mL/min; Gradient (B%): 50% B to 50% B in 22 min; Wave Length: 220/254 nm; RTl(min): 8.509; RT2(min): 14.741; Sample Solvent: ETOH: DCM=1: 1— HPLC] to afford rel-((3R*,8R*)-4-amino-3-methyl- 3,6,8,9-tetrahydro-lH-furo[3,4-d]pyrano[3,4-b]pyridin-8-yl)((4aS,10bS)-8- (difluoromethoxy)-2,3,4,4a,6,10b-hexahydro-lH-pyrano[3,2-b:5,4-b']dipyridin-l- yl)methanone isomer 4 (Example 25) (5.6 mg, 1%) as a white solid with retention time at 8.509 minute. MS ESI calculated for C24H26F2N4O5 [M+H]⁺, 489.19; found, 489.20. ¹H NMR (400 MHz, CD3OD) 3 7.87 - 7.29 (m, 2H), 6.98 - 6.83 (m, 1H), 5.91 - 5.39 (m, 1H), 5.39 - 5.29 (m, 1H), 5.14 - 5.04 (m, 1H), 5.03 - 4.95 (m, 1H), 4.85 - 4.81 (m, 1H), 4.80 - 4.73 (m, 2H), 4.73 - 4.66 (m, 1H), 4.66 - 4.55 (m, 1H), 4.55 - 3.79 (m, 2H), 3.17 - 2.99 (m, 1H), 2.90 - 2.14 (m, 2H), 1.97 - 1.51 (m, 4H), 1.50 - 1.40 (m, 3H).

Example 26: rel-((R)-4-amino-l,3,6,7,8,9-hexahydrofuro[3,4-c]quinotin-8-yl)((4aS,10bS)-8- chloro-2,3,4,4a,6,10b-hexahydro-lH-pyrano[3,2-b:5,4-b']dipyridin-l-yl)methanone

[1762] To a stirred solution of intermediate A40 (50 mg, 0.22 mmol) in DMF (1 mL) were added intermediate CAI isomer 2 (62 mg, 0.27 mmol), HATU (127 mg, 0.33 mmol) and DIEA (115 mg, 0.89 mmol). The resulting solution was stirred at 25 °C for 1 h. The reaction mixture was quenched with water and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered and concentrated under vacuum. The residue was purified by prep-HPLC with the following conditions: [Column: XBridge Prep Phenyl OBD Column 19*250 mm, 5 pm; Mobile Phase A: Water (10 mmol/L NH4HCO3), Mobile Phase B: ACN; Flow rate: 20 mL/min; Gradient (B%): 27% B to 37% B in 10 min; Wave Length: 254/220 nm] to afford rel-((R)-4-amino- l,3,6,7,8,9-hexahydrofuro[3,4-c]quinolin-8-yl)((4aS,10bS)-8-chloro-2,3,4,4a,6,10b- hexahydro-lH-pyrano[3,2-b:5,4-b']dipyridin-l-yl)methanone (Example 26) (22.8 mg, 54%) as a white solid. MS ESI calculated for C23H25CIN4O3 [M+H]⁺, 441.16; found, 441.10. 'H NMR (400 MHz, DMSO-d₆) 8 7.62 - 7.37 (m, 2H), 5.99 - 5.41 (m, 3H), 5.02 - 4.59 (m, 6H), 4.37 - 3.74 (m, 2H), 3.14 - 3.08 (m, 1H), 2.88 - 2.62 (m, 2H), 2.63 - 2.54 (m, 3H), 2.07 - 1.90 (m, 1H), 1.88 - 1.48 (m, 5H). [1763] Absolute stereochemistry of Example 26 was determined based on the absolute stereochemistry of A40. Accordingly, Example 26 is represented by the structure: having the chemical name of ((R)-4-amino-l,3,6,7,8,9-hexahydrofuro[3,4-c]quinohn-8- yl)((4aS,10bS)-8-chloro-2,3,4,4a,6,10b-hexahydro-lH-pyrano[3,2-b:5,4-b']dipyridin-l- yl)methanone.

Example 27: rel-((R)-4-amino-l,3,6,7,8,9-hexahydrofuro[3,4-c]quinohn-8- yl)((4aR*,6S*, 10bR*)-8-(difluoromethoxy)-6-methyl-2,3,4,4a,6, 1 Ob-hexahydro- 1H- isochromeno [4,3-b]pyridin- 1 -yl)methanone

[1764] To a stirred solution of intermediate A41 isomer 3 (60 mg, 0.22 mmol) and intermediate CAI isomer 2 (73 mg, 0.31 mmol) in DMF (3 mL) were added DIEA (86 mg, 0.67 mmol) and HATU (127 mg, 0.34 mmol) at room temperature. The resulting mixture was stirred at room temperature for 2 h. The reaction mixture was purified by prep-HPLC with the following conditions: [Column: XB ridge Prep Phenyl OBD Column 19*250 mm, 5 pm; Mobile Phase A: Water (10 mmol/L NH4HCO3), Mobile Phase B: MeOH; Flow rate: 20 mL/min; Gradient (B%): 66% B to 76% B in 10 min; Wave Length: 254/220 nm] to afford rel-((R)-4-amino-l,3,6,7,8,9-hexahydrofuro[3,4-c]quinolin-8-yl)((4aR*,6S*,10bR*)-8- (difluoromethoxy )-6-methyl-2, 3, 4, 4a, 6, 10b-hexahydro-lH-isochromeno[4,3-b]pyridin-l- yl)methanone (Example 27) (36.6 mg, 34%) as a white solid. MS ESI calculated for C26H29F2N3O4 [M+H]⁺, 486.21; found, 486.10. 'H NMR (400 MHz, DMSO-J₆) 87.56 - 7.22 (m, 2H), 7.21 - 6.90 (m, 2H), 5.66 (s, 2H), 5.59 - 5.21 (m, 1H), 5.01 - 4.59 (m, 5H), 4.11 - 4.02 (m, 2H), 3.80 - 3.76 (m, 1H), 3.07 - 3.03 (m, 2H), 2.83 - 2.61 (m, 3H), 2.05 - 1.77 (m, 2H), 1.76 - 1.22 (m, 7H).

Example 28: rel-((R)-4-amino-l,3,6,7,8,9-hexahydrofuro[3,4-c]quinohn-8- yl)((2R*,4aR*,9bR*)-2-methyl-7-(trifluoromethyl)-2,3,4,4a,5,9b-hexahydro-lH-indeno[l,2- b]pyridin- 1 -yl)methanone

Step 1:

[1765] To a stirred solution of intermediate A42 isomer 1 (50 mg, 0.20 mmol) and intermediate CA11 (81 mg, 0.29 mmol) in N,N-dimethylacetamide (1.5 mL) were added bis(2-oxo-l,3-oxazolidin-3-yl)phosphinoyl chloride (75 mg, 0.29 mmol) and EtaN (40 mg, 0.39 mmol) at room temperature. The resulting mixture was stirred at room temperature for 2 h. The reaction mixture was quenched by the addition of water and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under vacuum. The resulting residue was purified by normal phase flash column chromatography with a 25 g silica gel column and eluted with 0- 15% methanol in dichloromethane to afford rel-N-((R)-8-((2R*,4aR*,9bR*)-2-methyl-7- (trifhioromethyl)-2,3,4,4a,5,9b-hexahydro- lH-indeno[ 1 ,2-b]pyridine- 1 -carbonyl)- 1 ,3, 6, 7, 8, 9- hexahydrofuro[3,4-c]quinolin-4-yl)acetamide (27 mg, 27%) as a white solid. MS ESI calculated for C28H30F3N3O3 [M+H]⁺, 514.22; found, 514.20.

Step 2:

[1766] To a stirred solution of rel-N-((R)-8-((2R*,4aR*,9bR*)-2-methyl-7- (trifluoromethyl)-2,3,4,4a,5,9b-hexahydro-lH-indeno[l,2-b]pyridine-l-carbonyl)-l,3,6,7,8,9- hexahydrofuro[3,4-c]quinolin-4-yl)acetamide (20 mg, 0.04 mmol) in methanol (1 mL) was added K2CO3 (11 mg, 0.08 mmol) at room temperature. The resulting mixture was stirred at 80 °C for 2 h. The resulting mixture was concentrated under vacuum. The residue was filtered, the filter cake was washed with DCM/MeOH (5/1). The filtrate was concentrated under reduced pressure. The residue was purified by Prep-HPLC with the following conditions: [Column: XBridge Prep OBD Cl 8 Column 30 *150 mm, 5 pm; Mobile Phase A: Water (10 mmol/L NH4HCO3), Mobile Phase B: ACN; Flow rate: 60 mL/min; Gradient (B%): 30% B to 75% B in 12 min; Wave Length: 254/220 nm; RTl(min): 12] to afford 12 mg white solid, which was further purified by Prep-Chiral-HPLC with the following conditions: [Column: CHIRALPAK IB, 2*25 cm, 5 pm; Mobile Phase A: Hex(0.5% 2M NH₃-MeOH)— HPLC, Mobile Phase B: MeOH: DCM=1: 1-HPLC; Flow rate: 20 mL/min; Gradient (B%): isocratic 30; Wave Length: 220/254 nm; RTl(min): 5.52; RT2(min): 6.77; Sample Solvent: MeOH: DCM=1: 1-HPLC; Injection Volume: 1.5 mL; Number Of Runs: 1] to afford rel-((R)-4-amino-l, 3, 6,7,8, 9-hexahydrofuro[3,4-c]quinolin-8-yl)((2R*,4aR*,9bR*)- 2-methyl-7 -(trifhioromethyl)-2,3 ,4, 4a, 5 ,9b-hexahydro- IH-indeno [ 1 ,2-b]pyridin- 1 - yl)methanone (Example 28) (5.2 mg, 28%) as a white solid with retention time at 6.77 minute. MS ESI calculated for C26H28F3N3O2 [M+H]⁺, 472.21; found, 472.10. 'H NMR (400 MHz, DMSO-tfc) 8 7.74 - 7.45 (m, 2H), 7.22 - 7.19 (m, 1H), 5.97 - 5.43 (m, 3H), 5.10 - 4.76 (m, 4H), 4.74 - 4.18 (m, 1H), 3.23 - 3.06 (m, 2H), 3.04 - 2.79 (m, 2H), 2.70 - 2.67 (m, 2H), 2.64 - 2.53 (m, 2H), 2.10 - 2.02 (m, 1H), 1.85 - 1.65 (m, 1H), 1.65 - 1.47 (m, 2H), 1.47 - 1 .18 (m, 2H), 0.86 and 0.76 (d, J = 6.8 Hz, 3H). Example 29: rel-((R)-4-amino-l,3,6,7,8,9-hexahydrofuro[3,4-c]quinohn-8- yl)((4aR*,10bR*)-8-(trifluoromethyl)-3,4,4a,10b-tetrahydro-2H-chromeno[3,4-b]pyrazin- 1 (5H)-yl)methanone

Step-1:

[1767] To a stirred mixture of intermediate CAI isomer 2 (34 mg, 0.15 mmol) and DIEA (72 mg, 0.56 mmol) in DMF (1 mL) were added intermediate A32 isomer 1 (50 mg, 0.14 mmol) and 2-chloro-l-methylpyridin-l-ium iodide (46 mg, 0.18 mmol) at 0 °C under nitrogen atmosphere. The resulting mixture was stirred for additional 1 h at 0 °C. The mixture was quenched with water and extracted with EtOAc. The combined organic layers were washed with water, dried over anhydrous NaiSCX After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by flash column chromatography with 0-15% methyl alcohol in dichloromethane to afford rel-tert-butyl (4aR*,10bR*)-l-((R)-4-amino-l,3,6,7,8,9-hexahydrofuro[3,4-c]quinoline-8-carbonyl)-8- (trifluoromethyl)-l,2,3,4a,5,10b-hexahydro-4H-chromeno[3,4-b]pyrazine-4-carboxylate (30 mg, 37%) as a yellow oil. MS ESI calculated for C29H33F3N4O5 [M+H]⁺, 575.24; found, 575.25.

Step-2:

[1768] A mixture of rel-tert-butyl (4aR*,10bR*)-l-((R)-4-amino-l,3,6,7,8,9- hexahydrofuro[3,4-c]quinoline-8-carbonyl)-8-(trifluoromethyl)-l,2,3,4a,5,10b-hexahydro- 4H-chromeno[3,4-b]pyrazine-4-carboxylate (30 mg, 0.05 mmol) and HC1 in 1,4-dioxane (4.0 M) (1 mL) was stirred at 0 °C for 0.5 h. The resulting mixture was concentrated under vacuum. The crude residue was purified by Prep-HPLC with the following conditions: (Column: Xselect CSH OBD Column 30*150 mm, 5 pm; Mobile Phase A: Water (0.1% FA), Mobile Phase B: ACN; Flow rate: 60 mL/min; Gradient (B%): 5% B to 5% B in 2 min, 5% B tol5 % B in 10 min; Wave Length: 254/220 nm; RTl(min): 8) to afford rel-((R)-4-amino- l,3,6,7,8,9-hexahydrofuro[3,4-c]quinolin-8-yl)((4aR*,10bR*)-8-(trifluoromethyl)-3,4,4a,10b- tetrahydro-2H-chromeno[3,4-b]pyrazin-l(5H)-yl)methanone formate (Example 29) (5.2 mg, 19%) as a white solid. MS ESI calculated for (C24H25F3N4O3) [M+H]⁺, 475.19; found, 475.15. ¹H NMR (400 MHz, DMSO-d₆) 5 (ppm) 8.21 (s, 1H), 7.29 - 7.19 (m, 1H), 7.16 - 6.90 (m, 2H), 5.85 - 5.64 (m, 3H), 4.96 - 4.76 (m, 4H), 4.46 - 4.14 (m, 3H), 3.81 - 3.79 (m, 1H), 3.20 - 3.16 (m, 1H), 3.06 - 2.96 (m, 1H), 2.96 - 2.53 (m, 6H), 2.49 - 2.43 (m, 1H), 2.14 - 1.99 (m, 1H), 1.85 - 1.74 (m, 1H).

Example 30: ((R)-4-amino-l,3,6,7,8,9-hexahydrofuro[3,4-c][l,7]naphthyridin-8- yl)((4aS,10bS)-8-(trifluoromethyl)-2,3,4,4a,6,10b-hexahydro-lH-pyrano[3,2-b:5,4- b']dipyridin- l-yl)methanone

Step-1:

CA4 isomer 2

[1769] To a stirred solution of intermediate A29 (50 mg, 0.19 mmol), intermediate CA4 isomer 2 (65 mg, 0.19 mmol), DIEA (75 mg, 0.58 mmol) in N,N-dimethylacetamide (2 mL) was added 2-chloro-l-methylpyridin-l-ium iodide (74 mg, 0.29 mmol) at 0°C. The resulting mixture was stirred at room temperature for 2 h. The reaction mixture was quenched with water and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered and concentrated under vacuum to afford tertbutyl (R)-4-amino-8-((4aS,10bS)-8-(trifhioromethyl)-2,3,4,4a,6,10b-hexahydro-lH- pyrano[3,2-b:5,4-b']dipyridine-l-carbonyl)-3,6,8,9-tetrahydrofuro[3,4-c][l,7]naphthyridine- 7(lH)-carboxylate (60 mg, crude) as a yellow oil. MS ESI calculated for C28H32F3N5O5 [M+H]⁺, 576.24; found, 576.20.

[1770] To a solution of tert-butyl (R)-4-amino-8-((4aS,10bS)-8-(trifluoromethyl)- 2,3,4,4a,6,10b-hexahydro-lH-pyrano[3,2-b:5,4-b']dipyridine-l-carbonyl)-3,6,8,9- tetrahydrofuro[3,4-c][l,7]naphthyridine-7(lH)-carboxylate (60 mg, crude) in DCM (3 mL) was added TFA (1 mL), and the resulting mixture was stirred at room temperature for 30 min. The mixture was concentrated under vacuum. The crude product was purified by Prep-HPLC with the following conditions: [Column: XBridge Prep OBD C18 Column 30*150 mm; Mobile Phase A: Water (10 mmol/L NH4HCO3), Mobile Phase B: ACN; Flow rate: 60 mL/min; Gradient (B%): 5% B to 5% B in 2 min, 20% B to 40% B in 10 min; Wave Length: 254/220 nm; RTl(min): 9.8] to afford ((R)-4-amino-l,3,6,7,8,9-hexahydrofuro[3,4- c] [ 1 ,7]naphthyridin-8-yl)((4aS, 10bS)-8-(trifluoromethyl)-2,3,4,4a,6, 1 Ob-hexahydro- 1H- pyrano[3,2-b:5,4-b']dipyridin-l-yl)methanone (Example 30) (4.1 mg, 10%) as a white solid. MS ESI calculated for C23H24F3N5O3 [M+H]⁺, 476.18; found, 476.15. 'H NMR (400 MHz, DMSO-J₆) 87.99 - 7.67 (m, 2H), 5.88 (d, J = 6.0 Hz, 1H), 5.80 - 5.63 (m, 2H), 5.11 - 4.68 (m, 6H), 4.39 - 3.93 (m, 3H), 3.88 - 3.57 (m, 2H), 2.85 - 2.71 (m, 1H), 2.64 - 2.53 (m, 2H), 2.36 - 2.28 (m, 1H), 1.87 - 1.56 (m, 3H).

Example 31: ((R)-4-amino-l,3,6,7,8,9-hexahydrofuro[3,4-c][l,7]naphthyridin-8- yl)((4aS,9bS)-7-(trifluoromethyl)-3,4,4a,9b-tetrahydrofuro[2,3-b:4,5-b']dipyridin-l(2H)- yl)methanone

[1771] To a stirred solution of intermediate A26 isomer 2 (36 mg, 0.14 mmol), intermediate CA4 isomer 2 (50 mg, 0.14 mmol) and DIEA (57 mg, 0.44 mmol) in DMF (1 mL) was added HATU (85 mg, 0.22 mmol). The resulting mixture was stirred at room temperature for 2 h. The reaction mixture was quenched with water and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered and concentrated under vacuum to afford tert-butyl (R)-4-amino-8- ((4aS,9bS)-7-(trifhioromethyl)-l,2,3,4,4a,9b-hexahydrofuro[2,3-b:4,5-b']dipyridine-l- carbonyl)-3,6,8,9-tetrahydrofuro[3,4-c][l,7]naphthyridine-7(lH)-carboxylate (90 mg, crdue) as a yellow oil. MS ESI calculated for C27H30F3N5O5 [M+H]⁺, 562.22; found, 562.15.

Step-2:

[1772] To a solution of tert-butyl (R)-4-amino-8-((4aS,9bS)-7-(trifluoromethyl)- l,2,3,4,4a,9b-hexahydrofuro[2,3-b:4,5-b']dipyridine-l-carbonyl)-3,6,8,9-tetrahydrofuro[3,4- c][l,7]naphthyridine-7(lH)-carboxylate (80 mg, 0.14 mmol) in DCM (1 mL) was added TFA (0.3 mL), and then the mixture was stirred at room temperature for 30 min. The mixture was concentrated under vacuum. The residue was purified by prep-HPLC with the following conditions: [Column: XSelect CSH Prep Cl 8 OBD Column, 19*250 mm, 5 pm; Mobile Phase A: Water (10 mmol/L NH4HCO3), Mobile Phase B: MeOH; Flow rate: 20 mL/min; Gradient (B%): 47% B to 57% B in 10 min; Wave Length: 254/220 nm] to afford ((R)-4- amino- 1 ,3,6,7,8,9-hexahydrofuro[3,4-c] [1 ,7]naphthyridin-8-yl)((4aS,9bS)-7- (trifluoromethyl)-3,4,4a,9b-tetrahydrofuro[2,3-b:4,5-b']dipyridin-l(2H)-yl)methanone (Example 31) (15.0 mg, 22%) as a white solid. MS ESI calculated for C22H22F3N5O3 [M+H]⁺, 462.17; found, 462.15. 'H NMR (400 MHz, DMSO-J₆) 5 8.11 - 7.72 (m, 1H), 7.53 - 7.41 (m, 1H), 6.24 (d, J = 9.6 Hz, 1H), 5.71 (br, 2H), 5.27 - 5.17 (m, 1H), 5.01 - 4.78 (m, 4H), 4.22 - 3.96 (m, 1H), 3.95 - 3.60 (m, 3H), 3.01 - 2.90 (m, 1H), 2.85 - 2.65 (m, 2H), 2.49 - 2.35 (m, 1H), 1.97 - 1.41 (m, 4H).

Example 32: ((3R,8R)-4-amino-3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4-c][l,7]naphthyridin- 8-yl)((4aS,10bS)-8-(trifluoromethyl)-2,3,4,4a,6,10b-hexahydro-lH-pyrano[3,2-b:5,4- b']dipyridin- l-yl)methanone

Step 1:

CA6 isomer 3

[1773] To a stirred solution of intermediate CA6 isomer 3 (100 mg, 0.29 mmol) and intermediate A29 (88 mg, 0.34 mmol) in DMF (1 mL) were added DIEA (109 mg, 0.85 mmol) and HATU (163 mg, 0.43 mmol). The resulting mixture was stirred at room temperature 2 h. The reaction mixture was quenched with water and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under vacuum. The resulting residue was purified by normal phase flash column chromatography with a 25 g silica gel column and eluted with 0- 20% methanol in dichloromethane to afford tert-butyl (3R,8R)-4-amino-3-methyl-8- ((4aS,10bS)-8-(trifluoromethyl)-2,3,4,4a,6,10b-hexahydro-lH-pyrano[3,2-b:5,4- b']dipyridine-l-carbonyl)-3,6,8,9-tetrahydrofuro[3,4-c][l,7]naphthyridine-7(lH)-carboxylate (90 mg, 21%) as a white solid. MS ESI calculated for C29H34F3N5O5 [M+H]⁺, 590.25 found, 590.30.

Step-2:

[1774] To a stirred solution of tert-butyl (3R,8R)-4-amino-3-methyl-8-((4aS,10bS)-8- (trifluoromethyl)-2,3,4,4a,6, 1 Ob-hexahydro- 1 H-pyrano [3 ,2-b :5 ,4-b'] dipyridine- 1 -carbonyl)- 3,6,8,9-tetrahydrofuro[3,4-c][l,7]naphthyridine-7(lH)-carboxylate (85 mg, 0.14 mmol) in ethyl acetate (1 mL) was added hydrogen chloride (4.0 M in ethyl acetate) (2 mL). The resulting mixture was stirred at room temperature for 1 h. The solvents were removed under vacuum. The resultant residue was purified by Prep-HPLC with the following conditions: (Column: XBridge Prep OBD C18 Column30*150 mm; Mobile Phase A: Water (10 mmol/L NH4HCO3), Mobile Phase B: ACN; Flow rate: 60 mL/min; Gradient (B%): 5% B to 5% B in 2 min, 22% B to 42% B in 10 min; Wave Length: 254/220 nm; RTl(min): 9.5) to afford ((3R,8R)-4-amino-3-methyl-l ,3,6,7,8,9-hexahydrofuro[3,4-c] [1 ,7]naphthyridin-8- yl)((4aS,10bS)-8-(trifluoromethyl)-2,3,4,4a,6,10b-hexahydro-lH-pyrano[3,2-b:5,4- b']dipyridin-l-yl)methanone (Example 32) (22.1 mg, 33%) as a white solid. MS ESI calculated for C24H26F3N5O3 [M+H]⁺, 490.20 found, 490.15. 'H NMR (400 MHz, DMSO-d₆) 6 (ppm) 8.01 - 7.65 (m, 2H), 5.95 - 5.65 (m, 1H), 5.63 - 5.55 (m, 2H), 5.28 - 5.16 (m, 1H), 4.96 (dd, J= 13.6, 3.0 Hz, 1H), 4.91 -4.72 (m, 3H), 4.35 -4.20 (m, 1H), 4.17 - 3.92 (m, 2H), 3.84 - 3.60 (m 2H), 2.86 - 2.66 (m, 1H), 2.64 - 2.53 (m, 3H), 2.17 - 1.57 (m, 4H), 1.36 - 1.28 (m, 3H).

Example 33: rel-((R)-4-amino-3,6,8,9-tetrahydro- lH-furo[3,4-d]pyrano[3,4-b]pyridin-8- yl)((4aS,10bS)-8-(trifluoromethyl)-2,3,4,4a,6,10b-hexahydro-lH-pyrano[3,2-b:5,4- b']dipyridin- l-yl)methanone Step 1:

[1775] To a stirred solution of intermediate A29 (50 mg, 0.19 mmol) and intermediate CA3 isomer 1 (65 mg, 0.19 mmol) in DMAC (1 mL) were added DIEA (75 mg, 0.58 mmol) and 2- chloro-1 -methylpyridinium iodide (74 mg, 0.29 mmol). The resulting mixture was stirred at room temperature for 2 h. The resulting mixture was quenched with water and extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SC>4, filtered, and concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0 ~ 10% methanol in dichloromethane to afford rel-tert- butyl ((R)-8-((4aS,10bS)-8-(trifluoromethyl)-2,3,4,4a,6,10b-hexahydro-lH-pyrano[3,2-b:5,4- b']dipyridine-l-carbonyl)-3,6,8,9-tetrahydro-lH-furo[3,4-d]pyrano[3,4-b]pyridin-4- yl)carbamate (80 mg, 72%) as a yellow oil. MS ESI calculated for C28H31F3N4O6 [M+H]⁺, 577.22; found, 577.25.

Step 2:

[1776] To a solution of rel-tert-butyl ((R)-8-((4aS,10bS)-8-(trifluoromethyl)- 2,3,4,4a,6,10b-hexahydro-lH-pyrano[3,2-b:5,4-b']dipyridine-l-carbonyl)-3,6,8,9-tetrahydro- lH-furo[3,4-d]pyrano[3,4-b]pyridin-4-yl)carbamate (60 mg, 0.19 mmol) in DCM (0.8 mL) was added HC1 in 1,4-dioxane (4.0 M) (0.2 mL). The mixture was stirred at room temperature for 1 h. The resulting mixture was concentrated under reduced pressure. The residue was purified by Prep-HPLC with the following conditions (Column: XBridge Prep OBD C18 Column30*150 mm; Mobile Phase A: Water (10 mmol/L NH4HCO3), Mobile Phase B: ACN; Flow rate: 60 mL/min; Gradient (B%): 5% B to 5% B in 2 min, 24% B to 44% B in 10 min; Wave Length: 254/220 nm; RTl(min): 9.7 ) to afford rel-((R)-4-amino- 3,6,8,9-tetrahydro-lH-furo[3,4-d]pyrano[3,4-b]pyridin-8-yl)((4aS,10bS)-8-(trifluoromethyl)- 2,3 ,4, 4a, 6, 1 Ob-hexahydro- IH-pyrano [3 ,2-b:5 ,4-b'] dipyridin- 1 -yl)methanone (Example 33) (24.1 mg, 27%) as a white solid. MS ESI calculated for C23H23F3N4O4 [M+H]⁺, 477.17; found, 477.10. 'H NMR (400 MHz, DMSO- fc) 57.90 - 7.60 (m, 2H), 5.93 - 5.58 (m, 3H), 5.00 - 4.90 (m, 2H), 4.86 - 4.82 (m, 4H), 4.77 - 4.67 (m, 2H), 4.61 - 4.50 (m, 1H), 4.30 - 3.82 (m, 2H), 3.03 - 3.00 (m, 1H), 2.70 - 2.64 and 2.19 - 2.08 (m, 1H), 2.56 - 2.51 and 2.48 - 2.47 (m, 1H), 1.82 - 1.58 (m, 4H).

[1777] Absolute stereochemistry of Example 33 was determined by single crystal crystallography, and Example 33 is now represented by the structure: having the chemical name of ((S)-4-amino-3,6,8,9-tetrahydro-lH-furo[3,4-d]pyrano[3,4- b]pyridin-8-yl)((4aS,10bS)-8-(trifluoromethyl)-2,3,4,4a,6,10b-hexahydro-lH-pyrano[3,2- b :5 ,4-b'] dipyridin- 1 -yl)methanone.

Example 34: rel-((R)-4-amino-3,6,8,9-tetrahydro- lH-furo[3,4-d]pyrano[3,4-b]pyridin-8- yl)((4aS,9bS)-7-(trifluoromethyl)-3,4,4a,9b-tetrahydrofuro[2,3-b:4,5-b']dipyridin-l(2H)- yl)methanone

[1778] To a stirred solution of intermediate A26 isomer 2, intermediate CA3 isomer 1 (97 mg, 0.41 mmol) in DMF (2 mL) were added DIEA (159 mg, 1.23 mmol) and HATU (234 mg, 0.61 mmol). The resulting mixture was stirred at room temperature for 1 h. The mixture was quenched with water and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered and concentrated under vacuum. The crude product was treated with HC1 (4M in dioxane) (3 mL) and stirred at room temperature for 30 minute. The reaction was quenched by NaHCCh (sat.) and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered and concentrated under vacuum. The residue was purified by reversed phase flash column chromatography with 10-80% MeCN in Water, and then further purified by Prep-HPLC with the following conditions: [Column: Xselect CSH OBD Column 30*150 mm, 5 pm; Mobile Phase A: Water (0.1 % FA), Mobile Phase B: ACN; Flow rate: 60 mL/min; Gradient (B%): 5% B to 5% B in 2 min, 7% B to 27% B in 10 min; Wave Length: 254/220 nm; RTl(min): 10] to afford rel-((R)-4-amino-3,6,8,9-tetrahydro-lH-furo[3,4- d]pyrano[3,4-b]pyridin-8-yl)((4aS,9bS)-7-(trifhioromethyl)-3,4,4a,9b-tetrahydrofuro[2,3- b:4,5-b']dipyridin-l(2H)-yl)methanone (Example 34) (6 mg, 3%) as a white solid. MS ESI calculated for (C22H21F3N4O4) [M+H]⁺, 463.15; found, 463.15. 'H NMR (400 MHz, DMSO- d₆) 5 8.06 - 7.66 (m, 1H), 7.51 - 7.41 (m, 1H), 6.26 - 6.10 (m, 1H), 5.82 (s, 2H), 5.32 - 5.17 (m, 1H), 5.03 - 4.90 (m, 2H), 4.88 - 4.78 (m, 2H), 4.77 - 4.62 (m, 2H), 4.58 - 4.48 (m, 1H), 4.20 - 3.81 (m, 1H), 3.09 - 2.91 (m, 2H), 2.43 - 2.33 (m, 1H), 1.91 - 1.41 (m, 4H).

[1779] Based on the absolute stereochemistry of CA3 isomer 1, Example 34 is now represented by the structure:

having the chemical name of ((S)-4-amino-3,6,8,9-tetrahydro-lH-furo[3,4-d]pyrano[3,4- b]pyridin-8-yl)((4aS,9bS)-7-(trifluoromethyl)-3,4,4a,9b-tetrahydrofuro[2,3-b:4,5- b']dipyridin- 1 (2H)-yl)methanone.

Example 35: rel-((3R,8R)-4-amino-3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4- c][l,7]naphthyridin-8-yl)((4aS,10bS)-8-isopropyl-2,3,4,4a,6,10b-hexahydro-lH-pyrano[3,2- b :5 ,4-b']dipyridin- 1 -yl)methanone

Step 1:

CA6 isomer 3

[1780] To a stirred solution of intermediate A43 (50 mg, 0.18 mmol) and intermediate CA6 isomer 3 (65 mg, 0.18 mmol) in DMAC (2 mL) were added 2-chloro-l-methylpyridin-l-ium iodide (71 mg, 0.28 mmol) and DIEA (72 mg, 0.55 mmol) at room temperature. The resulting mixture was stirred at room temperature for 16 h. The resulting mixture was quenched with water and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous Na2SO4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-15% methanol in dichloromethane to afford rel-tert-butyl (3R,8R)-4-amino-8-((4aS,10bS)-8- isopropyl-2,3,4,4a,6,10b-hexahydro-lH-pyrano[3,2-b:5,4-b']dipyridine-l-carbonyl)-3- methyl-3,6,8,9-tetrahydrofuro[3,4-c][l,7]naphthyridine-7(lH)-carboxylate (21 mg, 20%) as a colorless oil. MS ESI calculated for C31H41N5O5 [M+H]⁺, 564.31; found, 564.25.

Step 2:

[1781] A mixture of rel-tert-butyl (3R,8R)-4-amino-8-((4aS,10bS)-8-isopropyl- 2,3,4,4a,6,10b-hexahydro-lH-pyrano[3,2-b:5,4-b']dipyridine-l-carbonyl)-3-methyl-3,6,8,9- tetrahydrofuro[3,4-c][l,7]naphthyridine-7(lH)-carboxylate (21 mg, 0.04 mmol) and HC1 (4.0 M in 1,4-dioxane) (1 mL) was stirred at room temperature for 16 h. The resulting mixture was concentrated under vacuum. The residue was purified by Prep-HPLC with the following conditions (Column: XBridge Prep OBD C18 Column 30*150 mm; Mobile Phase A: Water (10 mmol/L NH4HCO3), Mobile Phase B: ACN; Flow rate: 60 mL/min; Gradient (B%): 5% B to 5% B in 2 min, 18% B to 38% B in 10 min; Wave Length: 254/220 nm; RTl(min): 9.8) to afford rel-((3R,8R)-4-amino-3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4-c][l ,7]naphthyridin- 8-yl)((4aS,10bS)-8-isopropyl-2,3,4,4a,6,10b-hexahydro-lH-pyrano[3,2-b:5,4-b']dipyridin-l- yl)methanone (Example 35) (7.8 mg, 45%) as a white solid. MS ESI calculated for C26H33N5O3 [M+H]⁺, 464.26; found, 464.25. 'H NMR (400 MHz, DMSO-tfc) 87.65 - 7.09 (m, 2H), 5.83 - 5.48 (m, 3H), 5.27 - 5.19 (m, 1H), 4.99 - 4.93 (m, 1H), 4.86 - 4.57 (m, 3H), 4.34 - 3.88 (m, 3H), 3.76 and 3.66 (s, 2H), 3.02 - 2.94 (m, 1H), 2.78 - 2.57 (m, 3H), 1.80 - 1.57 (m, 4H), 1.34 - 1.30 (m, 3H), 1.25 - 1.21 (m, 7H).

[1782] Absolute stereochemistry of Example 35 was determined based on the absolute stereochemistry of A43. Accordingly, Example 35 is represented by the structure: having the chemical name of ((3R,8R)-4-amino-3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4- c][l,7]naphthyridin-8-yl)((4aS,10bS)-8-isopropyl-2,3,4,4a,6,10b-hexahydro-lH-pyrano[3,2- b:5,4-b']dipyridin- 1 -yl)methanone.

Example 36: rel-((3R,8R)-4-amino-3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4- c][l,7]naphthyridin-8-yl)((4aS,10bS)-8-cyclopropyl-2,3,4,4a,6,10b-hexahydro-lH- pyrano[3,2-b:5,4-b']dipyridin- 1 -yl)methanone

Step 1:

CA6 isomer 3

[1783] A mixture of intermediate A44 (50 mg, 0.22 mmol), intermediate CA6 isomer 3 (76 mg, 0.22 mmol), 2-chloro-l-methylpyridin-l-ium iodide (83 mg, 0.33 mmol) and DIEA (85 mg, 0.65 mmol) in N,N-dimethylacetamide (1 mL) was stirred at room temperature for 16 h. The resulting mixture was quenched with water and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous Na2SO4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-15% methanol in dichloromethane to afford rel-tert-butyl (3R,8R)-4-amino-8-((4aS,10bS)-8-cyclopropyl-2,3,4,4a,6,10b-hexahydro-lH- pyrano[3,2-b:5,4-b']dipyridine-l-carbonyl)-3-methyl-3,6,8,9-tetrahydrofuro[3,4- c][l,7]naphthyridine-7(lH)-carboxylate (29 mg, 24%) as a colorless oil. MS ESI calculated for C31H39N5O5 [M+H]⁺, 562.30; found, 562.25.

Step 2:

[1784] To a solution of rel-tert-butyl (3R,8R)-4-amino-8-((4aS,10bS)-8-cyclopropyl- 2,3,4,4a,6,10b-hexahydro-lH-pyrano[3,2-b:5,4-b^,]dipyridine-l-carbonyl)-3-methyl-3,6,8,9- tetrahydrofuro[3,4-c][l,7]naphthyridine-7(lH)-carboxylate (29 mg, 0.05 mmol) in EtOAc (1 mL) was added HC1 (4.0 M in 1,4-dioxane) (1 rnL). The mixture was stirred at room temperature for 16 h. The resulting mixture was concentrated under vacuum. The crude product was purified by Prep-HPLC with the following conditions (Column: XBridge Prep Phenyl OBD Column 19*250 mm, 5pm; Mobile Phase A: Water (10 mmol/L NH4HCO3), Mobile Phase B: ACN; Flow rate: 20 mL/min; Gradient (B%): 25% B to 35% B in 15 min; Wave Length: 254/220 nm; RTl(min): 13.5) to afford rel-((3R,8R)-4-amino-3-methyl- l,3,6,7,8,9-hexahydrofuro[3,4-c][l,7]naphthyridin-8-yl)((4aS,10bS)-8-cyclopropyl- 2,3,4,4a,6,10b-hexahydro-lH-pyrano[3,2-b:5,4-b']dipyridin-l-yl)methanone (Example 36) (3.5 mg, 15%) as a white solid. MS ESI calculated for C26H31N5O3 [M+H]⁺, 462.24; found, 462.25. ^XH NMR (400 MHz, DMSO-d₆) 57.54 - 7.13 (m, 2H), 5.80 - 5.46 (m, 3H), 5.27 - 5.18 (m, 1H), 5.01 - 4.51 (m, 4H), 4.30 - 3.90 (m, 3H), 3.76 and 3.66 (s, 2H), 2.79 - 2.58 (m, 2H), 2.10 - 2.00 (m, 1H), 1.78 - 1.58 (m, 4H), 1.35 - 1.49 (m, 3H), 1.00 - 0.73 (m, 5H).

[1785] Absolute stereochemistry of Example 36 was determined based on the absolute stereochemistry of A44. Accordingly, Example 36 is represented by the structure: having the chemical name of ((3R,8R)-4-amino-3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4- c][l,7]naphthyridin-8-yl)((4aS,10bS)-8-cyclopropyl-2,3,4,4a,6,10b-hexahydro-lH- pyranofS^-biS^-b'Jdipyridin- 1 -yl)methanone.

Example 37: rel-((3R,8R)-4-amino-3-methyl-l ,3,6,7,8,9-hexahydrofuro[3,4- c] [ 1 ,7]naphthyridin-8-yl)((4aS, 10bS)-8-chloro-2,3,4,4a,6, lOb-hexahydro- 1 H-pyrano[3,2- b:5,4-b']dipyridin- l-yl)methanone

Step 1:

CA6 isomer 3

[1786] To a stirred solution of intermediate A40 (50 mg, 0.22 mmol) and intermediate CA6 isomer 3 (78 mg, 0.22 mmol) in DMF (3 rnL) were added DIEA (86 mg, 0.67 mmol) and HATU (127 mg, 0.34 mmol). The resulting mixture was stirred at room temperature for 1 h.

The resulting mixture was quenched with water and extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous NazStX After filtration, the filtrate was concentrated under reduced pressure The residue was purified by Combi Flash (Biotage Isolera Prime) with a 40 g silica gel column and eluted with 0-10% methanol in dichloromethane to afford rel-tert-butyl (3R,8R)-4-amino-8-((4aS,10bS)-8-chloro- 2,3,4,4a,6,10b-hexahydro-lH-pyrano[3,2-b:5,4-b']dipyridine-l-carbonyl)-3-methyl-3,6,8,9- tetrahydrofuro[3,4-c][l,7]naphthyridine-7(lH)-carboxylate (100 mg, 81%) as a yellow oil. MS ESI calculated for C28H34CIN5O5 [M+H]⁺, 556.22; found, 556.20.

Step 2:

[1787] A solution of rel-tert-butyl (3R,8R)-4-amino-8-((4aS,10bS)-8-chloro- 2,3,4,4a,6,10b-hexahydro-lH-pyrano[3,2-b:5,4-b']dipyridine-l-carbonyl)-3-methyl-3,6,8,9- tetrahydrofuro[3,4-c][l,7]naphthyridine-7(lH)-carboxylate (100 mg, 0.18 mmol) and hydrogen chloride (4.0 M in EtOAc) (2 mL) was stirred at room temperature for 1 h. The resulting mixture was concentrated under vacuum. The residue was purified by prep-HPLC with the following conditions: [Column: XBridge Prep OBD C18 Column 30*150 mm; Mobile Phase A: Water (10 mmol/L NH4HCO3), Mobile Phase B: ACN; Flow rate: 60 mL/min; Gradient (B%): 5% B to 5% B in 2 min, 14% B to 34% B in 10 min; Wave Length: 254/220 nm; RTl(min): 9.4] to afford rel-((3R,8R)-4-amino-3-methyl-l,3,6,7,8,9- hexahydrofuro[3,4-c][l,7]naphthyridin-8-yl)((4aS,10bS)-8-chloro-2,3,4,4a,6,10b-hexahydro- lH-pyrano[3,2-b:5,4-b']dipyridin-l-yl)methanone (Example 37) (12.6 mg, 15%) as a white solid. MS (ESI) calculated for (C23H26CIN5O3) [M+H]⁺, 456.17; found, 456.15. ’H NMR (400 MHz, DMSO-cfc) 6 7.88 - 7.22 (m, 2H), 5.86 - 5.49 (m, 3H), 5.24 (d, J= 8.0 Hz, 1H), 5.07 - 4.89 (m, 1H), 4.89 - 4.57 (m, 3H), 4.34 - 3.92 (m, 3H), 3.82 - 3.57 (m, 2H), 2.81 - 2.58 (m, 2H), 2.12 - 1.93 (m, 1H), 1.89 - 1.52 (m, 4H), 1.42 - 1.27 (m, 3H).

[1788] Absolute stereochemistry of Example 37 was determined based on the absolute stereochemistry of A40. Accordingly, Example 37 is represented by the structure: having the chemical name of ((3R,8R)-4-amino-3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4- c][l,7]naphthyridin-8-yl)((4aS,10bS)-8-chloro-2,3,4,4a,6,10b-hexahydro-lH-pyrano[3,2- b:5,4-b']dipyridin- l-yl)methanone.

Example 38: ((3R,8R)-4-amino-3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4-c][l,7]naphthyridin- 8-yl)((4aS,9bS)-7-(trifluoromcthyl)-3,4,4a,9b-tctrahydrofuro[2,3-b:4,5-b']dipyridin-l(2H)- yl)methanone

Step 1:

CA6 isomer 3

[1789] To a stirred solution of intermediate A26 isomer 2 (50 mg, 0.20 mmol) in N,N- dimethylacetamide (1 mL) were added intermediate CA6 isomer 3 (71 mg, 0.20 mmol), 2- chloro-l-methylpyridin-l-ium iodide (63 mg, 0.25 mmol) and DIEA (79 mg, 0.61 mmol) at 25 °C. The resulting solution was stirred at 25 °C for 1 h. The reaction mixture was quenched with water and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered through paper, and concentrated under vacuum. The residue was purified by silica gel column chromatography, eluted with 1-10% MeOH in DCM to afford tert-butyl (3R,8R)-4-amino-3-methyl-8-((4aS,9bS)-7- (trifluoromethyl)-l,2,3,4,4a,9b-hexahydrofuro[2,3-b:4,5-b']dipyridine-l-carbonyl)-3,6,8,9- tetrahydrofuro[3,4-c][l,7]naphthyridine-7(lH)-carboxylate (70 mg, 56%) as a yellow oil. MS ESI calculated for (C28H32F3N5O5) [M+H]⁺, 576.18; found, 576.47.

Step 2:

[1790] A mixture of tert-butyl (3R,8R)-4-amino-3-methyl-8-((4aS,9bS)-7- (trifluoromethyl)-l,2,3,4,4a,9b-hexahydrofuro[2,3-b:4,5-b']dipyridine-l-carbonyl)-3,6,8,9- tetrahydrofuro[3,4-c][l,7]naphthyridine-7(lH)-carboxylate (70 mg, 0.12 mmol) and HC1 (4.0 M in EtOAc) (1 mL) was stirred at 25 °C for 1 h. The resulting mixture was concentrated under reduced pressure. The residue was purified by prep-HPLC with the following conditions: [Column: XBridge Prep OBD C18 Column 30*150 mm; Mobile Phase A: Water (10 mmol/L NH4HCO3), Mobile Phase B: ACN; Flow rate: 60 mL/min; Gradient (B%): 5% B to 5% B in 2 min, 21% B to 41% B in 10 min; Wave Length: 254/220 nm; RTl(min): 9.3] to afford ((3R,8R)-4-amino-3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4-c][l,7]naphthyridin-8- yl)((4aS,9bS)-7-(trifhioromethyl)-3,4,4a,9b-tetrahydrofuro[2,3-b:4,5-b']dipyridin-l(2H)- yl)methanone (Example 38) (20.9 mg, 76%) as a white solid. MS ESI calculated for C23H24F3N5O3 [M+H]⁺, 476.18; found, 476.47. 'H NMR (400 MHz, DMSO-d₆) 8 8.06 and 7.75 (d, J = 7.2 Hz, 1H), 7.51 and 7.44 (d, J = 7.2 Hz, 1H), 6.31 - 6.14 (m, 1H), 5.63 (s, 2H), 5.35 - 5.16 (m, 2H), 5.03 - 4.89 (m, 1H), 4.86 - 4.73 (m, 1H), 4.26 - 3.88 (m, 2H), 3.84 - 3.62 (m, 2H), 3.01 - 2.61 (m, 2H), 2.50 - 2.40 (m, 2H), 1.97 - 1.71 (m, 3H), 1.68 - 1.41 (m, 1H), 1.37 - 1.21 (m, 3H). Absolute stereochemistry was confirmed by single crystal X-ray crystallography.

Example 39: ((3R,8R)-4-amino-3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4-c][l,7]naphthyridin- 8-yl)((4aS,6R, 10bS)-6-methyl-8-(trifluoromethyl)-2,3,4,4a,6, lOb-hexahydro- 1 H-pyrano[3,2- b :5 ,4-b']dipyridin- 1 -yl)methanone

Step 1:

CA6 isomer 3

[1791] To a stirred solution of intermediate A45 isomer 1 (50 mg, 0.16 mmol) in DMF (2 mL) were added intermediate CA6 isomer 3 (57 mg, 0.16 mmol), HATU (92 mg, 0.24 mmol) and DIEA (63 mg, 0.49 mmol). The resulting solution was stirred at 25 °C for 1 h. The reaction mixture was quenched with water and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered through paper, and concentrated under vacuum. The residue was purified by Combi Flash (Biotage Isolera Prime) with a 25 g silica gel column that was eluted with 0-12% methanol in dichloromethane to afford tert-butyl (3R,8R)-4-amino-3-methyl-8-((4aS,6R,10bS)-6-methyl- 8-(trifluoromethyl)-2,3,4,4a,6, 1 Ob-hexahydro- 1 H-pyrano [3 ,2-b:5 ,4-b'] dipyridine- 1 -carbonyl)- 3,6,8,9-tetrahydrofuro[3,4-c][l,7]naphthyridine-7(lH)-carboxylate (100 mg, 61%) as yellow od. MS ESI calculated for C30H36F3N5O5 [M+H]⁺, 604.27; found, 604.25.

Step 2:

[1792] A mixture of tert-butyl (3R,8R)-4-amino-3-methyl-8-((4aS,6R,10bS)-6-methyl-8- (trifluoromethyl)-2,3,4,4a,6, 1 Ob-hexahydro- 1 H-pyrano [3 ,2-b :5 ,4-b'] dipyridine- 1 -carbonyl)- 3,6,8,9-tetrahydrofuro[3,4-c][l,7]naphthyridine-7(lH)-carboxylate (100 mg, 0.17 mmol) and HC1 (4.0 M in ethyl acetate) (1 mL) was stirred at 25 °C for 1 h. The solvents were removed under vacuum. The residue was purified by prep-HPLC with the following conditions: [Column: XSelect CSH Prep C18 OBD Column, 19*250 mm, 5 pm; Mobile Phase A: Water (10 mmol/L NH4HCO3), Mobile Phase B: MeOH; Flow rate: 20 mL/min; Gradient (B%): 74% B to 84% B in 10 min; Wave Length: 254/220 nm] to afford ((3R,8R)-4-amino-3- methyl-l,3,6,7,8,9-hexahydrofuro[3,4-c][l,7]naphthyridin-8-yl)((4aS,6R,10bS)-6-methyl-8- (trifhioromethyl)-2,3,4,4a,6, 1 Ob-hexahydro- 1 H-pyrano [3 ,2-b :5 ,4-b'] dipyridin- 1 - yl)methanone (Example 39) (5.5 mg, 6%) as a white solid. MS ESI calculated for C25H28F3N5O3 [M+H]⁺, 504.21; found, 504.20. 'H NMR (400 MHz, DMSO-d₆) 57.96 (d, J = 8.0 Hz, 1H), 7.85 (d, J= 8.0 Hz, 1H), 5.77 - 5.47 (m, 3H), 5.37 - 5.10 (m, 1H), 4.99 - 4.89 (m, 1H), 4.85 - 4.66 (m, 2H), 4.39 - 4.16 (m, 1H), 4.10 - 3.95 (m, 1H), 3.92 - 3.80 (m, 1H), 3.80 - 3.58 (m, 2H), 3.03 (t, J= 11.6 Hz, 1H), 2.77 - 2.62 (m, 2H), 2.50 - 2.39 (m, 2H), 1.94 - 1.72 (m, 2H), 1.58 (d, J = 6.4 Hz, 4H), 1.31 (d, J = 6.8 Hz, 3H).

Example 40: ((3R,8R)-4-amino-3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4- c][l,7]naphthyridin-8-yl)((4S,4aR,10bS)-4-fluoro-8-(trifhioromethyl)-2,3,4,4a,6,10b- hexahydro- 1 H-pyrano [3 ,2-b : 5 ,4-b '] dipyridin- 1 -yl)methanone

Step 1:

[1793] To a stirred solution of intermediate A46 isomer 1 (50 mg, 0.18 mmol) in N,N- dimethylacetamide (2 mL) were added intermediate CA6 isomer 3 (63 mg, 0.18 mmol), chloro- 1-methylpyridin-l-ium iodide (55 mg, 0.22 mmol) and DIEA (70 mg, 0.54 mmol). The resulting solution was stirred at 25 °C for 1 h. The reaction mixture was quenched with water and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered through paper, and concentrated under vacuum. The residue was purified by Combi Flash (Biotage Isolera Prime) with a 25 g silica gel column that was eluted with 0-12% methanol in dichloromethane to afford tert-butyl (3R,8R)-4-amino-8-((4S,4aR,10bS)-4-fluoro-8-(trifluoromethyl)-2,3,4,4a,6,10b-hexahydro- lH-pyrano[3,2-b:5,4-b']dipyridine-l-carbonyl)-3-methyl-3,6,8,9-tetrahydrofuro[3,4- c][l,7]naphthyridine-7(lH)-carboxylate (60 mg, 24%) as yellow oil. MS ESI calculated for C29H33F4N5O5 [M+H]⁺, 608.24; found, 608.20.

Step 2:

[1794] A mixture of tert-butyl (3R,8R)-4-amino-8-((4S,4aR, 10bS)-4-fhioro-8- (trifluoromethyl)-2,3,4,4a,6,10b-hexahydro-lH-pyrano[3,2-b:5,4-b']dipyridine-l-carbonyl)-3- methyl-3,6,8,9-tetrahydrofuro[3,4-c][l,7]naphthyridine-7(lH)-carboxylate (60 mg, 0.099 mmol) and hydrogen chloride (4.0 M in ethyl acetate) (1 mL) was stirred at 25 °C for 1 h. The solvents were removed under vacuum. The residue was purified by prep-HPLC with the following conditions: [Column: Xcelect CSH F-pheny OBD Column 19*250 mm, 5 pm; Mobile Phase A: Water (0.1% FA), Mobile Phase B: ACN; Flow rate: 25 mL/min; Gradient (B%): 5% B to 15% B in 10 min; Wave Length: 254/220 nm; RTl(min): 9.8] to afford ((3R,8R)-4-amino-3-methyl-l ,3,6,7,8,9-hexahydrofuro[3,4-c] [1 ,7]naphthyridin-8- yl)((4S,4aR,10bS)-4-fluoro-8-(trifluoromethyl)-2,3,4,4a,6,10b-hexahydro-lH-pyrano[3,2- b:5,4-b']dipyridin-l-yl)methanone (Example 40) (1.1 mg, 2%) as a white solid. MS ESI calculated for C24H25F4N5O3 [M+H]⁺, 508.19; found, 508.20. ¹H NMR (400 MHz, CD3OD) 8 8.06 - 7.59 (m, 2H), 6.25 - 5.55 (m, 1H), 5.44 - 5.07 (m, 4H), 5.02 - 4.91 (m, 2H), 4.62 - 4.38 (m, 1H), 4.36 - 4.18 (m, 1H), 4.13 (s, 1H), 4.04 - 3.82 (m, 1H), 3.24 (t, J= 12.4 Hz, 1H), 3.00 - 2.61 (m, 2H), 2.29 - 1.88 (m, 2H), 1.48 - 1.40 (m, 3H), 1.31 - 1.28 (m, 1H), 0.97 - 0.84 (m, 1H).

Example 41: ((3R,8R)-4-amino-3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4-c][l,7]naphthyridin-

8-yl)((4R,4aR,10bS)-4-fluoro-8-(trifluoromethyl)-2,3,4,4a,6,10b-hexahydro-lH-pyrano[3,2- b :5 ,4-b']dipyridin- 1 -yl)methanone

Step 1: [1795] To a stirred solution of intermediate A46 isomer 2 (30 mg, 0.11 mmol) in DMF (1 mL) were added intermediate CA6 isomer 3 (38 mg, 0.11 mmol), chloro- 1-methylpyridin-l- ium iodide (42 mg, 0.16 mmol) and DIEA (42 mg, 0.33 mmol). The resulting solution was stirred at room temperature for 16 h. The reaction mixture was quenched with water and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under vacuum. The residue was purified by silica gel column chromatography, eluted with MeOH/DCM (1/10) to afford tert-butyl (3R,8R)-4-amino-8-((4R,4aR,10bS)-4-fluoro-8-(trifluoromethyl)-2,3,4,4a,6,10b-hexahydro- lH-pyrano[3,2-b:5,4-b']dipyridine-l-carbonyl)-3-methyl-3,6,8,9-tetrahydrofuro[3,4- c][l,7]naphthyridine-7(lH)-carboxylate (60 mg, 60%) as yellow oil. MS ESI calculated for C29H33F4N5O5 [M+H]⁺, 608.24; found, 608.25.

Step 2:

[1796] A mixture of tert-butyl (3R,8R)-4-amino-8-((4R,4aR, 10bS)-4-fluoro-8- (trifluoromethyl)-2,3,4,4a,6, 1 Ob-hexahydro- 1 H-pyrano [3,2-b :5 ,4-b'] dipyridine- 1 -carbonyl)-3- methyl-3,6,8,9-tetrahydrofuro[3,4-c][l,7]naphthyridine-7(lH)-carboxylate (60 mg, 0.12 mmol) and HC1 (4.0 M in EtOAc) (1 mL) was stirred at 25 °C for 1 h. The resulting mixture was concentrated under reduced pressure. The residue was purified by prep-HPLC with the following conditions: [Column: XSelect CSH Prep C18 OBD Column, 19*250 mm, 5 pm; Mobile Phase A: Water (10 mmol/L NH4HCO3), Mobile Phase B: MeOH; Flow rate: 20 mL/min; Gradient (B%): 61% B to 71% B in 10 min; Wave Length: 254/220 nm] to afford ((3R,8R)-4-amino-3-methyl-l ,3,6,7,8,9-hexahydrofuro[3,4-c] [1 ,7]naphthyridin-8- yl)((4R,4aR,10bS)-4-fluoro-8-(trifluoromethyl)-2,3,4,4a,6,10b-hexahydro-lH-pyrano[3,2- b:5,4-b']dipyridin-l-yl)methanone (Example 41) (8.4 mg, 65%) as a white solid. MS ESI calculated for C24H25F4N5O3 [M+H]⁺, 508.19; found, 508.25. 'H NMR (400 MHz, DMSO- d₆) 5 8.07 - 7.55 (m, 2H), 6.16 - 5.84 (m, 1H), 5.72 - 5.56 (m, 2H), 5.24 - 5.18 (m, 1H), 5.12 - 5.08 (m, 1H), 5.01 - 4.90 (m, 3H), 4.87 - 4.77 (m, 1H), 4.47 - 4.32 (m, 1H), 4.21 - 4.02 (m, 2H), 3.85 - 3.56 (m, 2H), 2.90 - 2.64 (m, 3H), 2.36 - 2.28 (m, 1H), 2.07 - 2.04 (m, 1H), 1.89 - 1.48 (m, 1H), 1.43 - 1.30 (m, 3H).

Example 42: ((3R,8R)-4-amino-3-methyl-l ,3,6,7,8,9-hexahydrofuro[3,4-c] [1 ,7]naphthyridin- 8-yl)((4R,4aR,l0bS)-8-chloro-4-fluoro-2,3,4,4a,6,l0b-hexahydro-1H-pyrano[3,2-b:5,4- b']dipyridin- l-yl)methanone

Step-1:

CA6 isomer 3

[1797] A solution of intermediate A47 isomer 2 (30 mg, 0.12 mmol) and intermediate CA6 isomer 3 (56 mg, 0.16 mmol) in DMF (5 mL) were added DIEA (79 mg, 0.62 mmol) and HATU (235 mg, 0.62 mmol) at room temperature. The resulting mixture was stirred at room temperature for 16 h. The reaction mixture was quenched with water and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered and concentrated under reduced pressure. The residue was purified by flash column chromatography with 0-85% EtOAc in petroleum ether to afford tert-butyl (3R,8)-4- amino-8-((4R,4aR,10bS)-8-chloro-4-fluoro-2,3,4,4a,6,10b-hexahydro-lH-pyrano[3,2-b:5,4- b']dipyridine-l-carbonyl)-3-methyl-3,6,8,9-tetrahydrofuro[3,4-c][l,7]naphthyridine-7(lH)- carboxylate (50 mg, 70%) as a white solid. MS ESI calculated for C28H33CIFN5O5 [M+H]⁺, 574.22; found, 574.25.

Step-2:

[1798] A mixture of tert-butyl (3R,8R)-4-amino-8-((4R,4aR, 10bS)-8-chloro-4-fluoro- 2,3,4,4a,6,10b-hexahydro-lH-pyrano[3,2-b:5,4-b']dipyridine-l-carbonyl)-3-methyl-3,6,8,9- tetrahydrofuro[3,4-c][l,7]naphthyridine-7(lH)-carboxylate (50 mg, 0.08 mmol) and hydrogen chloride (4.0 M in ethyl acetate) (5.0 mL) was stirred at room temperature for 30 min. The reaction mixture was concentrated under reduced pressure. The residue was purified by Prep-HPLC with the following conditions: (Column: XBridge Prep OBD C18 Column30*150 mm; Mobile Phase A: Water (10 mmol/L NH4HCO3), Mobile Phase B: ACN; Flow rate: 60 mL/min; Gradient (B%): 5% B to 5% B in 2 min, 25% B to 45% B in 10 min; Wave Length: 254/220 nm; RTl(min): 9.3) to afford ((3R,8R)-4-amino-3-methyl- l,3,6,7,8,9-hexahydrofuro[3,4-c][l,7]naphthyridin-8-yl)((4R,4aR,10bS)-8-chloro-4-fluoro- 2,3 ,4, 4a, 6, 1 Ob-hexahydro- IH-pyrano [3 ,2-b:5 ,4-b'] dipyridin- 1 -yl)methanone (Example 42) (12.7 mg, 30%) as a white solid. MS ESI calculated for C23H25CIFN5O3 [M+H]⁺, 474.16; found, 474.15. 'H NMR (400 MHz, DMSO-d₆) 5 (ppm) 7.78 - 7.37 (m, 2H), 5.98 - 5.76 (m, 1H), 5.67 - 5.62 (m, 2H), 5.27 - 5.19 (m, 1H), 5.13 - 4.91 (m, 2H), 4.91 - 4.72 (m, 3H), 4.43 - 4.23 (m, 1H), 4.21 - 4.00 (m, 2H), 3.83 - 3.54 (m, 2H), 2.82 - 2.60 (m, 3H), 2.35 - 2.00 (m, 2H), 1.85 - 1.44 (m, 1H), 1.34 - 1.30 (m, 3H).

Example 43: ((3R,8R)-4-amino-3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4- c][l ,7]naphthyridin-8-yl)((4aS,6R,10bS)-8-chloro-6-methyl-2,3,4,4a,6,10b-hexahydro- lH-pyrano[3,2-b:5,4-b']dipyridin- l-yl)methanone hydrochloride

A78

[1799] To a stirred solution of intermediate A78 (60 mg, 0.22 mmol) and intermediate CA6, isomer 3 (76 mg, 0.22 mmol) in DMF (2 mL) were added DIEA (113 mg, 0.87 mmol) and HATU (124 mg, 0.33 mmol) at 0 °C. The resulting mixture was stirred at room temperature for 1 h. The resulting mixture was quenched with water and extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SC>4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0~8% methanol in dichloromethane ether to afford tert-butyl (3R,8R)-4-amino-8-((4aS,6R,10bS)-8-chloro-6-methyl-2,3,4,4a,6,10b- hexahydro- lH-pyrano[3,2-b:5,4-b']dipyridine- 1 -carbonyl)-3-methyl-3, 6,8,9- tetrahydrofuro[3,4-c][l,7]naphthyridine-7(lH)-carboxylate (90 mg, 72%) as a yellow oil.

[1800] A mixture of tert-butyl (3R,8R)-4-amino-8-((4aS,6R, 10bS)-8-chloro-6-methyl- 2,3,4,4a,6,10b-hexahydro-lH-pyrano[3,2-b:5,4-b^,]dipyridine-l-carbonyl)-3-methyl-3,6,8,9- tetrahydrofuro[3,4-c][l,7]naphthyridine-7(lH)-carboxylate (80 mg, 0.14 mmol) and hydrogen chloride (4.0 M in EtOAc) (2 mL) was stirred at room temperature for 1 h. The resulting mixture was concentrated under vacuum. The residue was purified by prep-HPLC with the following conditions: [Column: XSelect CSH Prep C18 OBD Column, 19*250 mm; Mobile Phase A: Water (0.05% HC1), Mobile Phase B: ACN; Flow rate: 25 mL/min;

Gradient (B%): 10% B to 20% B in 13 min; Wave Length: 254/220 nm; RTl(min): 12] to afford ((3R,8R)-4-amino-3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4-c][l,7]naphthyridin-8- yl)((4aS ,6R, 10bS)-8-chloro-6-methyl-2,3 ,4, 4a, 6, 1 Ob-hexahydro- 1 H-pyrano [3 ,2-b :5 ,4- b']dipyridin-l-yl)methanone hydrochloride (Example 43) (5.1 mg, 8%) as a yellow solid. MS (ESI) calculated for C24H28CIN5O3 [M+H]⁺, 470.19; found, 470.20. 'H NMR (400 MHz, DMSO-rfe) 8 10.74 - 9.45 (m, 2H), 7.73 (d, J = 8.4 Hz, 1H), 7.55 - 7.45 (m, 1H), 5.53 - 5.33 (m, 2H), 5.22 - 4.88 (m, 3H), 4.81 - 4.70 (m, 2H), 4.49 - 4.21 (m, 4H), 3.69 - 3.53 (m, 1H), 3.06 - 2.92 (m, 1H), 3.33 - 3.17 (m, 1H), 2.83 - 2.65 (m, 1H), 2.06 - 1.87 (m, 2H), 1.76 - 1.47 (m, 6H), 1.42 - 1.31 (m, 3H). Example 44: ((3R,8R)-4-amino-3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4-c][l,7]naphthyridin- 8-yl)((4R*,4aR*,10bR*)-4-methyl-8-(trifluoromethyl)-2,3,4,4a,6,10b-hexahydro-lH- pyrano[3,2-b:5,4-b']dipyridin-l-yl)methanone

A80, isomer 2

[1801] Followed the procedure of Example 39 with intermediate A80, isomer 2 (20 mg, 0.073 mmol) and intermediate CA6, isomer 3 (26 mg, 0.073 mmol) to afford ((3R,8R)-4- amino-3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4-c][l,7]naphthyridin-8-yl)((4R*,4aR*,10bR*)- 4-methyl-8-(trifhioromethyl)-2,3,4,4a,6,10b-hexahydro-lH-pyrano[3,2-b:5,4-b']dipyridin-l- yl)methanone (Example 44) (2.9 mg, 17%) as a white solid. MS ESI calculated for C25H28F3N5O3 [M+H]⁺, 504.21; found, 504.20. 'H NMR (300 MHz, DMSO-d₆) 8 8.08 (d, J = 8.1 Hz, 1H), 7.84 (d, J = 8.1 Hz, 1H), 5.60 (s, 2H), 5.47 (s, 1H), 5.22 (d, J = 6.9 Hz, 1H), 4.98 - 4.83 (m, 2H), 4.78 - 4.57 (m, 2H), 4.11 - 3.93 (m, 2H), 3.77 (s, 3H), 3.16 - 2.93 (m, 1H), 2.78 - 2.60 (m, 1H), 2.47 - 2.34 (m, 1H), 2.32 - 2.06 (m, 1H), 1.80 - 1.60 (m, 1H), 1.37 - 1.21 (m, 4H), 1.11 (d, 7 = 6.6 Hz, 3H).

Example 45: ((3R,8R)-4-amino-3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4-c][l,7]naphthyridin- 8-yl)((4R*,4aS*,9bR*)-4-fluoro-7-(trifluoromethyl)-3,4,4a,9b-tetrahydrofuro[2,3-b:4,5- b']dipyridin- 1 (2H)-yl)methanone

A79, isomer 1

[1802] Followed the procedure of Example 39 with intermediate A79, isomer 1 (10 mg, 0.04 mmol) and intermediate CA6, isomer 3 (14 mg, 0.04 mmol) to afford ((3R,8R)-4-amino- 3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4-c][l,7]naphthyridin-8-yl)((4R*,4aS*,9bR*)-4- fhioro-7-(trifhioromethyl)-3,4,4a,9b-tetrahydrofuro[2,3-b:4,5-b']dipyridin-l(2H)- yl)methanone (Example 45) (1.8 mg, 10%) as a white solid. MS (ESI) calculated for C23H23F4N5O3 [M+H]⁺, 494.17; found,494.20. 'H NMR (400 MHz, DMSO-d₆) 8 8.02 - 7.64 (m, 1H), 7.60 - 7.47 (m, 1H), 6.50 - 6.40 (m, 1H), 5.68 - 5.59 (m, 2H), 5.23 - 5.21 (m, 1H), 5.17 - 5.05 (m, 1H), 4.99 - 4.75 (m, 3H), 4.48 - 4.25 (m, 1H), 4.03 - 4.01 (m, 1H), 3.79 - 3.59 (m, 2H), 3.06 - 2.66 (m, 2H), 2.53 - 2.57 and 2.48 - 2.44 (m, 2H), 2.09 - 1.92 (m, 1H), 1.91 - 1.58 (m, 1H), 1.35 - 1.28 (m, 3H).

Example 46: ((3R,8R)-4-amino-3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4-c][l,7]naphthyridin- 8-yl)((4R*,4aS*,9bS*)-7-chloro-4-methyl-3,4,4a,9b-tetrahydrofuro[2,3-b:4,5-b']dipyridin- 1 (2H)-yl)methanone

[1803] Followed the procedure of Example 38 with intermediate A84 (10 mg, 0.04 mmol) and intermediate CA6, isomer 3 (15 mg, 0.04 mmol) and separated by Prep-Chiral-HPLC with the following conditions: [Column: CHIRALPAK IB, 2*25 cm, 5 pm; Mobile Phase A: Hex (0.5% 2M NH₃-MeOH)-HPLC, Mobile Phase B: ETOH: DCM=1: 1-HPLC; Flow rate: 20 mL/min; Gradient (B%): isocratic 35% B to 35% in 17min; Wave Length: 220/254 nm; RT1 (min): 11.85; RT2 (min): 14.17; Sample Solvent: MeOH: DCM=1: 1-HPLC; Injection Volume: 2.0 mL; Number Of Runs: 1] to afford ((3R,8R)-4-amino-3-methyl-l,3,6,7,8,9- hexahydrofuro[3,4-c][l,7]naphthyridin-8-yl)((4R*,4aS*,9bS*)-7-chloro-4-methyl-3,4,4a,9b- tetrahydrofuro[2,3-b:4,5-b']dipyridin-l(2H)-yl)methanone (Example 46) (0.7 mg, 4%) as a white solid with retention time at 14.17 minute. MS ESI calculated for C23H26CIN5O3 [M+H]⁺, 456.17; found, 456.15. 'H NMR (400 MHz, CD3OD) 57.90 - 7.45 (m, 1H), 7.12 - 6.89 (m, 1H), 6.34 - 5.95 (m, 1H), 5.42 - 5.28 (m, 1H), 5.15 - 5.05 (m, 1H), 4.97 - 4.89 (m, 1H), 4.75 - 4.60 (m, 1H), 4.25 -4.12 (m, 1H), 4.11 -4.02 (m, 1H), 3.99 - 3.81 (m, 2H), 3.15 - 3.02 (m, 1H), 2.82 - 2.55 (m, 2H), 1.92 - 1.69 (m, 2H), 1.52 - 1.39 (m, 4H), 1.25 - 1.15 (m, 3H).

Example 47: ((3R,8R)-4-amino-3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4-c][l,7]naphthyridin- 8-yl)((4R*,4aS*,9bR*)-4-methoxy-7-(trifluoromethyl)-3,4,4a,9b-tetrahydrofuro[2,3-b:4,5- b']dipyridin- 1 (2H)-yl)methanone

A81 isomer 2

[1804] Followed the procedure of Example 38 with intermediate A81, isomer 2 (27 mg, 0.10 mmol) and intermediate CA6, isomer 3 (35 mg, 0.10 mmol) afford ((3R,8R)-4-amino-3- methyl-l,3,6,7,8,9-hexahydrofuro[3,4-c][l,7]naphthyridin-8-yl)((4R*,4aS*,9bR*)-4- methoxy-7-(trifluoromethyl)-3,4,4a,9b-tetrahydrofuro[2,3-b:4,5-b']dipyridin-l(2H)- yl)methanone (Example 47) (6.9 mg, 10%) as a white solid. MS ESI calculated for C24H26F3N5O4 [M+H]⁺, 506.19; found, 506.20. 1H NMR (400 MHz, DMSO-d₆) 8 8.13 - 7.68 (m, 1H), 7.54 - 7.40 (m, 1H), 6.29 - 6.20 (m, 1H), 5.69 - 5.59 (m, 2H), 5.30 (dd, J = 9.2, 3.2 Hz, 1H), 5.27 - 5.19 (m, 1H), 4.99 - 4.72 (m, 1H), 4.85 - 4.71 (m, 1H), 4.27 - 3.86 (m, 2H), 3.86 - 3.62 (m, 3H), 3.32 - 3.31 (m, 3H), 3.07 - 2.73 (m, 1H), 2.71 - 2.52 (m, 2H), 2.49 - 2.38 (m, 1H), 2.15 - 1.89 (m, 1H), 1.73 - 1.50 (m, 1H), 1.35 - 1.29 (m, 3H).

Example 48: ((3R,8R)-4-amino-3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4-c][l,7]naphthyridin- 8-yl)((4R*,4aR*,9bS*)-4-methoxy-7-(trifluoromethyl)-3,4,4a,9b-tetrahydrofuro[2,3-b:4,5- b']dipyridin- 1 (2H)-yl)methanone [1805] Followed the procedure of Example 38 with intermediate A81 isomer 1 (50 mg, 0.16 mmol) and intermediate CA6, isomer 3 (56 mg, 0.16 mmol) to afford ((3R,8R)-4-amino- 3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4-c][l,7]naphthyridin-8-yl)((4R,4aR,9bS)-4-methoxy- 7-(trifluoromethyl)-3,4,4a,9b-tetrahydrofuro[2,3-b:4,5-b']dipyridin-l (2H)-yl)methanone (Example 48) (11.0 mg, 66%) as a white solid. MS ESI calculated for C24H26F3N5O4 [M+H]⁺, 506.19; found, 506.20. 'H NMR (400 MHz, DMSO-d₆) 3 7.98 - 7.62 (m, 1H), 7.57 - 7.43 (m, 1H), 6.36 - 6.31 (m, 1H), 5.67 - 5.59 (m, 2H), 5.27 - 5.18 (m, 1H), 5.00 - 4.89 (m, 2H), 4.83 - 4.75 (m, 1H), 4.37 - 4.20 (m, 1H), 4.01 (d, J = 6.8 Hz, 1H), 3.80 - 3.59 (m, 2H), 3.52 - 3.43 (m, 1H), 3.36 (d, J = 9.2 Hz, 3H), 3.01 - 2.68 (m, 2H), 2.49 - 2.42 (m, 2H), 1.96 - 1.85 (m, 1H), 1.54 - 1.37 (m, 1H), 1.33 - 1.30 (m, 3H).

Example 49: ((3R,8R)-4-amino-3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4-c][l,7]naphthyridin- 8-yl)((4aR*,9bR*)-7-chloro-3,4,4a,9b-tetrahydrofuro[2,3-b:4,5-b']dipyridin-l(2H)- yl)methanone

A90

[1806] Followed the procedure of Example 38 with intermediate A90 (50 mg, 0.202 mmol) and intermediate CA6, isomer 3 (70.69 mg, 0.202 mmol) to afford ((3R,8R)-4-amino-3- methyl-l,3,6,7,8,9-hexahydrofuro[3,4-c][l,7]naphthyridin-8-yl)((4aR*,9bR*)-7-chloro- 3,4,4a,9b-tetrahydrofuro[2,3-b:4,5-b']dipyridin-l(2H)-yl)methanone (Example 49) (18.9 mg, 46%) as a white solid. MS ESI calculated for C22H24CIN5O3 [M+H]⁺, 442.16; found, 442.16. 'H NMR (400 MHz, DMSO-d₆) 87.87 and 7.55 (s, 1H), 7.11 - 7.07 (m, 1H), 6.15 - 6.10 (m, 1H), 5.63 (br, 2H), 5.25 - 5.19 (m, 2H), 4.94 - 4.88 (m, 1H), 4.78 (t, J = 13.2 Hz, 1H), 4.28 - 3.64 (m, 4H), 2.94 - 2.92 (m, 1H), 2.77 - 65 (m, 2H), 2.43 - 2.32 (m, 2H), 1.95 - 1.90 (m, 1H), 1.80 - 1.74 (m, 1H), 1.69 - 1.46 (m, 1H), 1.35 - 1.22 (m, 3H).

Example 50: ((3R,8R)-4-amino-3-methyl-l ,3,6,7,8,9-hexahydrofuro[3,4-c] [1 ,7]naphthyridin- 8-yl)((4R* ,4aS* , 1 ObS *)-4-methyl-8-(trifluoromethyl)-2,3 ,4, 4a, 6, 1 Ob-hexahydro- 1 H- pyrano[3,2-b:5,4-b']dipyridin- 1 -yl)methanone

A80 isomer 1

[1807] Followed the procedure of Example 39 with intermediate A80, isomer 1 (50 mg, 0.18 mmol) and intermediate CA6, isomer 3 (64 mg, 0.18 mmol) to afford ((3R,8R)-4-amino- 3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4-c][l,7]naphthyridin-8-yl)((4R*,4aS*,10bS*)-4- methyl-8-(trifluoromethyl)-2,3,4,4a,6,10b-hexahydro-lH-pyrano[3,2-b:5,4-b']dipyridin-l- yl)methanone (Example 50) (7.4 mg, 35%) as a white solid. MS ESI calculated for C25H28F3N5O3 [M+H]⁺, 504.21; found, 504.20. 1H NMR (400 MHz, DMSO-d₆) 87.96 - 7.82 (m, 1H), 7.81 - 7.60 (m, 1H), 5.94 - 5.62 (m, 3H), 5.28 - 5.18 (m, 1H), 4.99 - 4.92 (m, 1H), 4.89 - 4.69 (m, 3H), 4.35 - 3.94 (m, 2H), 3.88 - 3.69 (m, 3H), 2.83 - 2.53 and 2.47 - 2.40 (m, 5H), 1.83 - 1.72 (m, 1H), 1.63 (t, J= 12.8 Hz, 1H), 1.35 - 1.27 (m, 3H), 1.06 - 0.98 (m, 3H).

Example 51: ((3R,8R)-4-amino-3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4-c][l,7]naphthyridin- 8-yl)((2R*,4aS*,9bS*)-2-methyl-7-(trifluoromethyl)-3,4,4a,9b-tetrahydrofuro[2,3-b:4,5- b']dipyridin- 1 (2H)-yl)methanone

[1808] To a stirred solution of intermediate A82 (100 mg, 0.38 mmol) in THF (2 mL) were sequentially added intermediate CA6, isomer 3 (135 mg, 0.38 mmol), TEA (117 mg, 1.16 mmol) and bis(2-oxo-l,3-oxazolidin-3-yl)phosphinoyl chloride (147 mg, 0.58 mmol). The resulting solution was stirred at room temperature for 16 h. The resulting mixture was quenched with water and the mixture was extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SO4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-20% MeOH in DCM to afford tert-butyl (3R,8R)-4-amino-3- methyl-8-((2R*,4aS*,9bS*)-2-methyl-7-(trifluoromethyl)-l,2,3,4,4a,9b-hexahydrofuro[2,3- b:4,5-b']dipyridine-l-carbonyl)-3,6,8,9-tetrahydrofuro[3,4-c][l,7]naphthyridine-7(lH)- carboxylate (80 mg, 35%) as a yellow solid.

[1809] To mixture of tert-butyl (3R,8R)-4-amino-3-methyl-8-((2R*,4aS*,9bS*)-2-methyl- 7-(trifluoromethyl)-l,2,3,4,4a,9b-hexahydrofuro[2,3-b:4,5-b']dipyridine-l-carbonyl)-3,6,8,9- tetrahydrofuro[3,4-c][l,7]naphthyridine-7(lH)-carboxylate (80 mg, 0.13 mmol) in ethyl acetate (1 mL) was added hydrochloric acid (4.0 M solution in ethyl acetate) (1 mL). The mixture was stirred at room temperature for 1 h. The resulting mixture was concentrated under reduced pressure. The crude product was purified by Prep-HPLC with the following conditions (Column: Xselect CSH OBD Column 30* 150mm, 5pm; Mobile Phase A: Water (0.1% FA), Mobile Phase B: ACN; Flow rate: 60 mL/min; Gradient (B%): 5% B to 5% B in 2 min, 5% B to 25% B in 10 min; Wave Length: 254/220 nm; RTl(min): 9) to afford ((3R,8R)-4-amino-3-methyl-l ,3,6,7,8,9-hexahydrofuro[3,4-c][l,7]naphthyridin-8- yl)((2R*,4aS*,9bS*)-2-methyl-7-(trifluoromethyl)-3,4,4a,9b-tetrahydrofuro[2,3-b:4,5- b']dipyridin-l(2H)-yl)methanone formate (Example 51) (7.3 mg, 10%) as a white solid. MS ESI calculated for C24H26F3N5O3 [M+H]⁺, 490.19; found, 490.10. 'H NMR (400 MHz, DMSO-de) 8 8.19 (s, 1H), 8.09 and 7.75 (d, J = 8.0 Hz, 1H), 7.48 and 7.41 (d, J = 8.0 Hz, 1H), 6.48 and 6.33 (d, J = 8.0 Hz, 1H), 5.66 (s, 2H), 5.37 - 5.19 (m, 2H), 4.98 and 4.95 (d, J = 4.0 Hz, 1H), 4.87 - .T1 (m, 1H), 4.59 - 3.88 (m, 3H), 3.80 (d, J= 16.0 Hz, 1H), 3.76 - 3.66 (m, 1H), 2.99 - 2.76 (m, 1H), 2.43 (d, J = 14.6 Hz, 1H), 2.06 - 1.39 (m, 3H), 1.39 - 1.26 (m, 3H), 1.25 - 0.99 (m, 1H), 0.91 and 0.82 (d, J= 8.0 Hz, 3H).

Example 52: ((3R,8R)-4-amino-3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4-c][l,7]naphthyridin- 8-yl)((3R*,4aS*,9bS*)-3-fluoro-7-(trifluoromethyl)-3,4,4a,9b-tetrahydrofuro[2,3-b:4,5- b']dipyridin- 1 (2H)-yl)methanone

A91 isomer 1

[1810] Followed the procedure of Example 39 with intermediate A91 isomer 1 (50 mg, 0.19 mmol) and intermediate CA6, isomer 3 (67 mg, 0.19 mmol) to afford ((3R,8R)-4-amino- 3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4-c][l,7]naphthyridin-8-yl)((3R*,4aS*,9bS*)-3-fluoro- 7-(trifluoromethyl)-3,4,4a,9b-tetrahydrofuro[2,3-b:4,5-b']dipyridin-l (2H)-yl)methanone (Example 52) (22 mg, 68%) as a white solid. MS ESI calculated for C23H23F4N5O3 [M+H]⁺, 494.17; found, 494.20. *H NMR (400 MHz, DMSO-d₆) 8 8.26 - 7.80 (m, 1H), 7.59 - 7.45 (m, 1H), 6.20 - 6.16 (m, 1H), 5.65 (s, 2H), 5.31 - 5.16 (m, 2H), 5.13 - 4.89 (m, 2H), 4.83 - 4.72 (m, 1H), 4.57 - 4.30 (m, 1H), 4.26 - 3.70 (m, 3H), 3.17 - 2.76 (m, 2H), 2.63 - 2.59 (m, 1H), 2.47 - 2.44 (m, 1H), 2.33 - 2.31 (m 2H), 1.33 - 1.30 (m, 3H).

Example 53: (4aR*, 1 ObR*)- 1 -((3R,8R)-4-amino-3-methyl- 1 ,3,6,7,8,9-hexahydrofuro[3,4- c][l,7]naphthyridine-8-carbonyl)-2,3,4,4a,6,10b-hexahydro-lH-pyrano[3,2-b:5,4- b']dipyridine-8-carbonitrile

[1811] Followed the procedure of Example 39 with intermediate A100 (40 mg, 0.19 mmol) and intermediate CA6, isomer 3 (77 mg, 0.22 mmol) to afford (4aR*,10bR*)-l- ((3R,8R)-4-amino-3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4-c][l,7]naphthyridine-8-carbonyl)- 2,3,4,4a,6,10b-hexahydro-lH-pyrano[3,2-b:5,4-b']dipyridine-8-carbonitrile (Example 53) (4.3 mg, 30%) as a white solid. MS ESI calculated for C24H26N6O3 [M+H]⁺, 447.21; found, 447.20. 'H NMR (400 MHz, DMSO-d₆) 5 8.15 - 7.58 (m, 2H), 5.93 - 5.51 (m, 3H), 5.23 (s, 1H), 4.99 - 4.87 (m, 1H), 4.85 - 4.66 (m, 3H), 4.35 - 3.98 (m, 3H), 3.83 - 3.56 (m, 2H), 2.84 - 2.69 (m, 1H), 2.48 - 2.39 (m, 1H), 2.15 - 1.50 (m, 5H), 1.40 - 1.19 (m, 4H).

Example 54: ((3R,8R)-4-amino-3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4-c][l,7]naphthyridin- 8-yl)((4R*,4aR*,10bR*)-8-chloro-4-methyl-2,3,4,4a,6,10b-hexahydro-lH-pyrano[3,2-b:5,4- b']dipyridin- l-yl)methanone

A83 isomer 2

[1812] Followed the procedure of Example 38 with intermediate CA6, isomer 3 (34 mg, 0.14 mmol) and intermediate A83, isomer 2 (50 mg, 0.14 mmol) to afford ((3R,8R)-4-amino- 3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4-c][l,7]naphthyridin-8-yl)((4R*,4aR*,10bR*)-8- chloro-4-methyl-2,3 ,4, 4a, 6, 1 Ob-hexahydro- 1 H-pyrano[3 ,2-b :5 ,4-b']dipyridin- 1 -yl)methanone (Example 54) (12.7 mg, 85%) as a white solid. MS ESI calculated for C24H28CIN5O3 [M+H]⁺, 470.19; found, 470.25. 'H NMR (400 MHz, DMSO-rf₆) 8 7.75 - 7.27 (m, 2H), 5.88 - 5.53 (m, 3H), 5.28 - 5.18 (m, 1H), 5.00 - 4.88 (m, 1H), 4.86 - 4.77 (m, 1H), 4.70 - 4.59 (m, 2H), 4.35 - 3.95 (m, 2H), 3.82 - 3.48 (m, 3H), 2.82 - 2.62 (m, 1H), 2.63 - 2.57 (m, 1H), 2.46 - 2.27 (m, 2H), 2.19 - 2.02 (m, 1H), 1.87 - 1.71 (m, 1H), 1.70 - 1.54 (m, 1H), 1.36 - 1.27 (m, 3H), 1.05 - 0.82 (m, 3H).

Example 55: ((3R,8R)-4-amino-3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4-c][l,7]naphthyridin- 8-yl)((4R*,4aS*,9bR*)-7-chloro-4-methoxy-3,4,4a,9b-tetrahydrofuro[2,3-b:4,5-b']dipyridin- 1 (2H)-yl)methanone

A92 Isomer 1

[1813] Followed the procedure of Example 38 with intermediate A92 isomer 1 (48 mg, 0.2 mmol) and intermediate CA6, isomer 3 (70 mg, 0.2 mmol) to afford ((3R,8R)-4-amino-3- methyl-l,3,6,7,8,9-hexahydrofuro[3,4-c][l,7]naphthyridin-8-yl)((4R*,4aS*,9bR*)-7-chloro- 4-methoxy-3,4,4a,9b-tetrahydrofuro[2,3-b:4,5-b']dipyridin-l(2H)-yl)methanone (Example 55) (10.9 mg, 16.5%) as a white solid. MS ESI calculated for C23H26CIN5O4 [M+H]⁺, 472.17; found, 472.10. 'H NMR (400 MHz, DMSO-d₆) 67.49 - 7.98 (m, 1H), 7.14 - 7.14 (m, 1H), 6.15 (dd, 7= 9.1, 3.0 Hz, 1H), 5.64 (d, J = 7.1 Hz, 2H), 5.30 - 5.17 (m, 2H), 4.99 - 4.88 (m, 1H), 4.84 - 4.71 (m, 1H), 4.27 - 3.94 (m, 2H), 3.93 - 3.58 (m, 3H), 3.33 (s, 3H), 3.02 - 2.71 (m, 2H), 2.69 - 2.54 (m, 1H), 2.47 - 2.30 (m, 1H), 2.18 - 1.94 (m, 1H), 1.71 - 1.47 (m, 1H), 1.39 - 1.26 (m, 3H).

Example 56: ((3R,8R)-4-amino-3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4- c][l,7]naphthyridin-8-yl)((3aR*,8bR*)-6-(trifluoromethyl)-2,3,3a,8b-tetrahydro-lH- benzofuro[3,2-b]pyrrol-l-yl)methanone, isomer 1

[1814] Followed the procedure of Example 38 with intermediate A93 isomer 1 (30 mg, 0.13 mmol) and intermediate CA6, isomer 3 (69 mg, 0.19 mmol) to afford ((3R,8R)-4-amino- 3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4-c][l,7]naphthyridin-8-yl)((3aR*,8bR*)-6- (trifhioromethyl)-2,3,3a,8b-tetrahydro- lH-benzofuro[3,2-b]pyrrol- l-yl)methanone, isomer 1 (Example 56) (14.5 mg, 39%) as a white solid. MS ESI calculated for C23H23F3N4O3 [M+H]⁺, 461.17; found 461.20. ^JH NMR (400 MHz, DMSO-d₆) 8 7.73 (d, J = 7.6 Hz, 1H), 7.36 - 7.22 (m, 1H), 7.18 (d, J = 1.6 Hz, 1H), 5.68 (d, J = 6.4 Hz, 1H), 5.61 (s, 2H), 5.52 - 5.45 (m, 1H), 5.26 - 5.14 (m, 1H), 4.93 - 4.83 (m, 1H), 4.70 (d, J = 13.2 Hz, 1H), 4.27 - 4.09 (m, 1H), 3.73 (s, 3H), 3.32 - 3.24 (m, 2H), 2.60 - 2.53 (m, 1H), 2.38 - 2.18 (m, 3H), 1.29 (d, J = 6.0 Hz, 3H).

Example 57: ((3R,8R)-4-amino-3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4-c][l,7]naphthyridin-

S-yl)((4aR*,9bR*)-7-(difluoromethoxy)-3,4,4a,9b-tetrahydrofuro[2,3-b:4,5-b']dipyridin-

1 (2H)-yl)methanone

[1815] Followed the procedure of Example 39 with intermediate A71 (50 mg, 0.21 mmol) and intermediate CA6, isomer 3 (72 mg, 0.21 mmol) to afford ((3R,8R)-4-amino-3-methyl- l,3,6,7,8,9-hexahydrofuro[3,4-c][l,7]naphthyridin-8-yl)((4aR*,9bR*)-7-(difluoromethoxy)- 3,4,4a,9b-tetrahydrofuro[2,3-b:4,5-b']dipyridin-l(2H)-yl)methanone (Example 57) (9.5 mg, 57%) as a white solid. MS ESI calculated for C23H25F2N5O4 [M+H]⁺, 473.19; found, 473.15. 'H NMR (400 MHz, DMSO- ₆) 87.98 - 7.42 (m, 2H), 6.64 - 6.60 (m, 1H), 6.09 - 6.01 (m, 1H), 5.69 (s, 2H), 5.23 - 5.18 (m, 2H), 4.99 - 4.91 (m, 1H), 4.78 (t, J = 14.8 Hz, 1H), 4.25 - 3.87 (m, 2H), 3.86 - 3.74 (m, 2H), 2.97 - 2.71 (m, 1H), 2.70 - 2.58 (m, 1H), 2.44 - 2.31 (m, 2H), 1.95 - 1.48 (m, 4H), 1.35 - 1.30 (m, 3H).

Example 58: ((3R,8R)-4-amino-3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4-c][l,7]naphthyridin- 8-yl)((3R,4aR*,9bR*)-7-(difluoromethoxy)-3-methoxy-3,4,4a,9b-tetrahydrofuro[2,3-b:4,5- b']dipyridin- 1 (2H)-yl)methanone

[1816] Followed the procedure of Example 51 with intermediate A104 (60 mg, 0.22 mmol) and intermediate CA6, isomer 3 (77 mg, 0.22 mmol) to afford ((3R,8R)-4-amino-3-methyl- l,3,6,7,8,9-hexahydrofuro[3,4-c][l,7]naphthyridin-8-yl)((3R,4aR*,9bR*)-7- (difhjoromethoxy)-3-methoxy-3,4,4a,9b-tetrahydrofuro[2,3-b:4,5-b']dipyridin-l(2H)- yl)methanone (Example 58) (11.7 mg, 14%) as a white solid. MS ESI calculated for C24H27F2N5O5 [M+H]⁺, 504.20; found, 504.20. ¹H NMR (300 MHz, DMSO) 5 8.10 - 7.33 (m, 2H), 6.66 - 6.57 (m, 1H), 5.98 (d, J = 8.8 Hz, 1H), 5.60 - 5.59 (m, 2H), 5.34 - 5.08 (m, 2H), 5.02 - 4.87 (m, 1H), 4.78 (t, J = 11.8 Hz, 1H), 4.53 - 4.24 (m, 1H), 4.05 - 3.99 (m, 1H), 3.88 - 3.51 (m, 3H), 3.23 (s, 3H), 2.80 - 2.62 (m, 2H), 2.50 - 2.26 (m, 2H), 2.19 - 1.96 (m, 2H), 1.32 (d, J = 6.2 Hz, 3H).

Example 59: ((3R,8R)-4-amino-3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4-c][l,7]naphthyridin- 8-yl)((4R*,4aS*,9bR*)-4-fluoro-7-(trifluoromethyl)-3,4,4a,9b-tetrahydrofuro[2,3-b:4,5- b']dipyridin- 1 (2H)-yl)methanone

A79, isomer 2

[1817] Followed the procedure of Example 39 with intermediate A79, isomer 2 (40 mg, 0.17 mmol) and intermediate CA6, isomer 3 (49 mg, 0.17 mmol) to afford ((3R,8R)-4-amino- 3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4-c][l,7]naphthyridin-8-yl)((4R*,4aS*,9bR*)-4- fhioro-7-(trifhioromethyl)-3,4,4a,9b-tetrahydrofuro[2,3-b:4,5-b']dipyridin-l(2H)- yl)methanone (Example 59) (3.4 mg, 22%) as a white solid. MS (ESI) calculated for C23H23F4N5O3 [M+H]⁺, 494.17; found, 494.25. 'H NMR (400 MHz, DMSO-rf₆) 8 8.06 - 7.63 (m 1H), 7.56 - 7.42 (m, 1H), 6.32 (d, J = 9.2 Hz, 1H), 5.64 (s, 2H), 5.30 - 5.07 (m, 3H), 4.83 - 4.75 (m, 1H), 4.82 - 4.77 (m, 1H), 4.34 - 4.14 (m, 1H), 4.06 - 4.00 (m, 1H), 3.76 - 3.65 (m, 2H), 3.13 - 2.70 (m, 2H), 2.60 - 2.55 and 2.48 - 2.44 (m, 2H), 2.08 - 1.91 (m, 2H), 1.33 - 1.31 (m, 3H).

Example 60: ((3R,8R)-4-amino-3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4-c][l,7]naphthyridin- 8-yl)((3R*,4aR*,9bR*)-3-fluoro-7-(trifluoromethyl)-3,4,4a,9b-tetrahydrofuro[2,3-b:4,5- b']dipyridin- 1 (2H)-yl)methanone

A91 isomer 2

[1818] Followed the procedure of Example 39 with intermediate A91 isomer 2 (50 mg, 0.19 mmol) and intermediate CA6, isomer 3 (67 mg, 0.19 mmol) to afford ((3R,8R)-4-amino- 3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4-c][l,7]naphthyridin-8-yl)((3R*,4aR*,9bR*)-3- fhioro-7-(trifhioromethyl)-3,4,4a,9b-tetrahydrofuro[2,3-b:4,5-b']dipyridin-l(2H)- yl)methanone (Example 60) (5.3 mg, 21%) as a white solid. MS ESI calculated for C23H23F4N5O3 [M+H]⁺, 494.17; found, 494.20. 'H NMR (400 MHz, CD3OD) 8 8.20 - 7.85 (m, 1H), 7.44 - 7.40 (m, 1H), 6.34 - 6.21 (m, 1H), 5.34 - 5.12 (m, 3H), 5.09 - 5.05 (m, 1H), 4.94 - 4.89 (m, 1H), 4.72 - 4.37 (m, 1H), 4.27 - 4.06 (m, 1H), 3.96 - 3.93 (m, 2H), 3.06 - 2.40 (m, 4H), 2.36 - 2.18 (m, 1H), 1.43 - 1.42 (m, 3H).

Example 61: ((3R,8R)-4-amino-3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4- c][l,7]naphthyridin-8-yl)((3R,4aS,9bS)-3-methoxy-7-(trifluoromethyl)-3,4,4a,9b- tetrahydrofuro[2,3-b:4,5-b']dipyridin-l(2H)-yl)methanone

[1819] Followed the procedure of Example 38 with intermediate A94 and intermediate CA6, isomer 3 (102 mg, 0.29 mmol) to afford ((3R,8R)-4-amino-3-methyl-l,3,6,7,8,9- hexahydrofuro[3,4-c][l,7]naphthyridin-8-yl)((3R,4aS,9bS)-3-methoxy-7-(trifluoromethyl)- 3,4,4a,9b-tetrahydrofuro[2,3-b:4,5-b']dipyridin-l(2H)-yl)methanone (Example 61) (12.4 mg, 9%) as a white solid. MS ESI calculated for C24H26F3N5O4 [M+H]⁺, 506.19; found, 506.25. 'H NMR (300 MHz, DMSO-d₆) 5 8.1 1 - 7.75 (m, 1H), 7.51 - 7.43 (m, 1H), 6.15 (d, J= 9.0 Hz, 1H), 5.64 (d, J = 5.4 Hz, 2H), 5.24 - 5.19 (m, 2H), 4.98 - 4.92 (m, 1H), 4.82 - 4.75 (m, 1H), 4.53 - 4.28 (m, 1H), 4.17 - 3.90 (m, 1H), 3.87 - 3.45 (m, 3H), 3.22 - 3.18 (m, 3H), 2.93 - 2.69 (m, 1H), 2.64 - 2.54 (m, 1H), 2.42 (d, J = 4.4 Hz, 1H), 2.20 - 1.76 (m, 3H), 1.31 (d, J = 6.1 Hz, 3H).

Example 62: ((3R,8R)-4-amino-3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4-c][l,7]naphthyridin- 8-yl)((3R*,4aS*,9bS*)-7-(difluoromethoxy)-3-fluoro-3,4,4a,9b-tetrahydrobenzofuro[3,2- b]pyridin- 1 (2H)-yl)methanone A 39, isomer 2

[1820] Followed the procedure of Example 51 with intermediate A39, isomer 2 (62 mg, 0.239 mmol) and intermediate CA6, isomer 3 (100 mg, 0.287 mmol) to afford ((3R,8R)-4- amino-3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4-c][l,7]naphthyridin-8-yl)((3R*,4aS*,9bS*)- 7-(difluoromethoxy)-3-fluoro-3,4,4a,9b-tetrahydrobenzofuro[3,2-b]pyridin-l(2H)- yl)methanone (Example 62) (7.9 mg, 15%) as a white solid. MS ESI calculated for C24H25F3N4O4. [M+H]⁺, 491.18 found, 491.25. ’H NMR (400 MHz, CD3OD) 8 7.61 - 7.23 (m, 1H), 7.09 - 6.82 (m, 1H), 6.81 - 6.43 (m, 2H), 6.16 - 5.82 (m, 1H), 5.33 - 5.28 (m, 1H), 5.20 - 4.90 (m, 3H), 4.62 - 4.58 (m, 1H), 4.42 - 4.22 (m, 1H), 4.16 - 4.02 (m,lH), 3.97 - 3.92 (m, 2H), 3.19 - 2.69 (m, 2H), 2.69 - 2.32 (m, 2H), 2.30 - 2.04 (m, 1H), 1.43 (t, J= 5.6 Hz, 3H).

Example 63: ((3R,8R)-4-amino-3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4-c][l,7]naphthyridin- 8-yl)((4R*,4aR*,10bR*)-8-chloro-4-methyl-2,3,4,4a,6,10b-hexahydro-lH-pyrano[3,2-b:5,4- b']dipyridin- l-yl)methanone [1821] Followed the procedure of Example 38 with intermediate A83 isomer 1(50 mg, 0.20 mmol) and intermediate CA6, isomer 3 (73 mg, 0.20 mmol) to afford ((3R,8R)-4-amino-3- methyl-l,3,6,7,8,9-hexahydrofuro[3,4-c][l,7]naphthyridin-8-yl)((4R*,4aR*,10bR*)-8-chloro- 4-methyl-2,3,4,4a,6,10b-hexahydro-lH-pyrano[3,2-b:5,4-b']dipyridin-l-yl)methanone (Example 63) (5.0 mg, 99.3%) as a white solid. MS ESI calculated for C24H28CIN5O3 [M+H]⁺, 470.19; found, 470.20. 'H NMR (400 MHz, DMSO-d₆) 3 7.86 (d, J= 8.4 Hz, 1H), 7.45 (d, J = 8.0 Hz, 1H), 5.62 (s, 2H), 5.36 (d, J = 5.6 Hz, 1H), 5.22 (d, J= 6.0 Hz, 1H), 5.00 - 4.90 (m, 1H), 4.84 - 4.68 (m, 2H), 4.59 - 4.52 (m, 1H), 4.00 - 3.90 (m, 2H), 3.82 - 3.68 (m, 3H), 3.11 - 3.01 (m, 1H), 2.74 - 2.63 (m, 1H), 2.48 - 2.33 (m, 1H), 2.20 - 2.05 (m, 1H), 1.76 - 1.68 (m, 1H), 1.39 - 1.19 (m, 5H), 1.09 (d, J = 6.8 Hz, 3H).

Example 64: (4aR*,9bR*)- l-((3R,8R)-4-amino-3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4- c][l,7]naphthyridine-8-carbonyl)-l,2,3,4,4a,9b-hexahydrobenzofuro[3,2-b]pyridine-7- carbonitrile, isomer 1

[1822] Followed the procedure of Example 38 with intermediate CA6, isomer 3 (50 mg, 0.14 mmol) and intermediate A27, isomer 1 (29 mg, 0.14 mmol) to afford (4aR*,9bR*)-l- ((3R,8R)-4-amino-3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4-c][l,7]naphthyridine-8-carbonyl)- l,2,3,4,4a,9b-hexahydrobenzofuro[3,2-b]pyridine-7-carbonitrile, isomer 1 (Example 64) (15 mg, 36%) as a white solid. MS ESI calculated for C24H25N5O3 [M+H] ⁺, 432.20; found, 432.20. ¹H NMR (400 MHz, DMSO-d₆) 57.51 - 7.24 (m, 3H), 6.36 - 6.13 (m, 1H), 5.63 (s, 2H), 5.28 - 5.19 (m, 1H), 5.19 - 5.06 (m, 1H), 5.00 -4.86 (m, 1H), 4.80 (t, 7 = 12.8 Hz, 1H), 4.18 - 3.80 (m, 2H), 3.80 - 3.63 (m, 2H), 2.99 - 2.63 (m, 2H), 2.49 - 2.26 (m, 2H), 1.91 - 1.44 (m, 4H), 3.12 (d, J= 6.0 Hz, 3H).

Example 65: (4aR*,9bR*)- l-((3R,8R)-4-amino-3-methyl- l,3,6,7,8,9-hexahydrofuro[3,4- c] [ 1 ,7]naphthyridine- 8-carbonyl)- 1 ,2,3 ,4,4a, 9b-hexahydrobenzofuro [3 ,2-b]pyridine-7 - carbonitrile, isomer 2

[1823] Followed the procedure of Example 38 with intermediate CA6, isomer 3 (40 mg, 0.11 mmol) and intermediate A27, isomer 2 (23 mg, 0.11 mmol) to afford (4aR*,9bR*)-l- ((3R,8R)-4-amino-3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4-c][l,7]naphthyridine-8-carbonyl)- l,2,3,4,4a,9b-hexahydrobenzofuro[3,2-b]pyridine-7-carbonitrile, isomer 2 (Example 65) (25.2 mg, 44%) as a white solid. MS ESI calculated for C24H25N5O3 [M+H]⁺, 432.20; found, 432.25. ^JH NMR (400 MHz, DMSO-d₆) 87.82 - 7.14 (m, 3H), 6.25 - 6.12 (m, 1H), 5.70 - 5.55 (m, 2H), 5.30 - 5.17 (m, 1H), 5.15 - 5.05 (m, 1H), 5.00 - 4.88 (m, 1H), 4.84 - 4.70 (m, 1H), 4.20 - 4.04 (m, 1H), 4.04 - 3.86 (m, 1H), 3.84 - 3.61 (m, 2H), 2.92 - 2.60 (m, 2H), 2.50 - 2.26 (m, 2H), 1.92 - 1.39 (m, 4H), 1.32 (d, J = 6.0 Hz, 3H). Example 66: ((3R,8R)-4-amino-3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4-c][l,7]naphthyridin- 8-yl)((4R*,4aR*,9bS*)-7-chloro-4-methoxy-3,4,4a,9b-tetrahydrofuro[2,3-b:4,5-b']dipyridin- 1 (2H)-yl)methanone

A92 isomer 2

[1824] Followed the procedure of Example 38 with intermediate A92, isomer 2 (48 mg, 0.2 mmol) and intermediate CA6, isomer 3 (70 mg, 0.2 mmol) to afford ((3R,8R)-4-amino-3- methyl-l,3,6,7,8,9-hexahydrofuro[3,4-c][l,7]naphthyridin-8-yl)((4R*,4aR*,9bS*)-7-chloro- 4-methoxy-3,4,4a,9b-tetrahydrofuro[2,3-b:4,5-b']dipyridin-l(2H)-yl)methanone (Example 66) (8.4 mg, 13%) as a white solid. MS ESI calculated for C23H26CIN5O4 [M+H]⁺, 472.17; found, 472.10; 'H NMR (400 MHz, DMSO-d₆) 3 7.83 - 7.41 (m, 1H), 7.17 - 7.08 (m, 1H), 6.29 - 6.13 (m, 1H), 5.63 (d, J= 3.7 Hz, 2H), 5.23 (s, 1H), 5.01 - 4.71 (m, 3H), 4.37 - 4.11 (m, 1H), 4.06 - 3.88 (m, 1H), 3.80 - 3.58 (m, 2H), 3.54 - 3.43 (m, 1H), 3.37 (s, 3H), 3.04 - 2.88 (m, 1H), 2.76 - 2.63 (m, 1H), 2.47 - 2.40 (m, 2H), 1.99 - 1.80 (m, 1H), 1.63 - 1.37 (m, 1H), 1.36 - 1.27 (m, 3H).

Example 67: ((3R,8R)-4-amino-3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4-c][l,7]naphthyridin- 8-yl)((4aR*,9bR*)-7-(difhioromethyl)-3,4,4a,9b-tetrahydrofuro[2,3-b:4,5-b']dipyridin-l(2H)- yl)methanone

[1825] To a stirred mixture of intermediate CA6, isomer 3 (50 mg, 0.14 mmol) and intermediate A95 (39 mg, 0.17 mmol) in N,N-dimethylacetamide (1 mL) were added CMPI (55 mg, 0.21 mmol) and DIEA (56 mg, 0.43 mmol). The resulting mixture was stirred at room temperature for 1 h under nitrogen atmosphere. The resulting mixture was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0 - 10% MeOH in DCM to afford tert-butyl (3R,8R)-4-amino-8-((4aR*,9bR*)-7- (difluoromethyl)-l,2,3,4,4a,9b-hexahydrofuro[2,3-b:4,5-b']dipyridine-l-carbonyl)-3-methyl- 3,6,8,9-tetrahydrofuro[3,4-c][l,7]naphthyridine-7(lH)-carboxylate (50 mg, 62.7%, 80% de) as a fight brown solid.

[1826] A mixture of tert-butyl (3R,8R)-4-amino-8-((4aR*,9bR*)-7-(difluoromethyl)- 1,2, 3, 4,4a, 9b-hexahydrofuro[2,3-b:4,5-b']dipyridine-l-carbonyl)-3-methyl-3, 6,8,9- tetrahydrofuro[3,4-c][l,7]naphthyridine-7(lH)-carboxylate (50 mg, 80% de) and HC1 in dioxane (1 mL) was stirred at room temperature for 1 h under nitrogen atmosphere. The resulting mixture was concentrated under reduced pressure. The crude product was purified by Prep-HPLC with the following conditions: (Column: XB ridge Prep OBD C18 Column30*150 mm; Mobile Phase A: Water (10 mmol/L NH4HCO3), Mobile Phase B: ACN; Flow rate: 60 mL/tnin; Gradient (B%): 5% B to 5% B in 2 min, 15% B to 35% B in 10 min; Wave Length: 254/220 nm; RTl(min): 9.3) and further purified by Prep-Chiral-HPLC with the following conditions: (Column: CHIRAL ART Cellulose-SZ 2*25 cm, 5 pm; Mobile Phase A: Hex (0.5% 2 M NH₃-MeOH)-HPLC, Mobile Phase B: MeOH: DCM=1: 1-HPLC; Flow rate: 20 mL/min; Gradient (B%): isocratic 40% B to 40% in 23 min; Wave Length: 220/254 nm; RTl(min): 10.89; RT2(min): 14.23; Sample Solvent: MeOH: DCM=1: 1-HPLC; Injection Volume: 1.5 mL; Number Of Runs: 1) to afford ((3R,8R)-4-amino-3-methyl- l,3,6,7,8,9-hexahydrofuro[3,4-c][l,7]naphthyridin-8-yl)((4aR*,9bR*)-7-(difluoromethyl)- 3,4,4a,9b-tetrahydrofuro[2,3-b:4,5-b']dipyridin-l(2H)-yl)methanone (Example 67) (10.7 mg, 26% yield) as an off-white solid with retention time at 14.23 min. MS ESI calculated for C23H25F2N5O3 [M+H]⁺, 458.19; found, 458.15. ¹H NMR (400 MHz, DMSO-d₆) 8 8.10 - 7.58 (m, 1H), 7.39 - 7.18 (m, 1H), 7.06 - 6.64 (m, 1H), 6.19 (t, J= 9.2 Hz, 1H), 5.63 (s, 2H), 5.40 - 5.11 (m, 2H), 5.07 - 4.88 (m, 1H), 4.79 (t, J = 12.4 Hz, 1H), 4.26 - 3.88 (m, 2H), 3.86 - 3.61 (m, 2H), 2.98 - 2.66 (m, 2H), 2.50 - 2.34 (m, 2H), 1.95 - 1.68 (m, 3H), 1.68 - 1.44 (m, 1H), 1.32 (d, J = 6.0 Hz, 3H).

Example 68: ((3R,8R)-4-amino-3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4-c][l,7]naphthyridin- 8-yl)((3aR*,8bR*)-6-(trifluoromethyl)-2,3,3a,8b-tetrahydro-lH-benzofuro[3,2-b]pyrrol-l- yl)methanone, isomer 2

[1827] To a stirred solution of intermediate A93, isomer 2 (30 mg, 0.13 mmol) in N,N- dimethylacetamide (2 mL) were added intermediate CA6, isomer 3 (69 mg, 0.20 mmol), CMPI (40 mg, 0.16 mmol) and DIEA (51 mg, 0.40 mmol). The resulting solution was stirred at 25 °C for 1 h. The resulting mixture was quenched with water and extracted with EtOAc. The combined organic layers were dried over anhydrous NaiSC After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0 ~ 10% MeOH in DCM to afford tert-butyl (3R,8R)-4-amino- 3-methyl-8-((3aR*,8bR*)-6-(trifluoromethyl)-2,3,3a,8b-tetrahydro-lH-benzofuro[3,2- b]pyrrole- 1 -carbonyl)-3 ,6,8 ,9-tetrahydrofuro [3 ,4-c] [ 1 ,7]naphthyridine-7 ( 1 H)-carboxylate (50 mg, 43%) as a yellow oil. This product (50 mg, 0.089 mmol) was dissolved in HC1 (4.0 M in EtOAc) (2 mL) and the mixture was stirred at 25 °C for 1 h. The resulting mixture was concentrated under reduced pressure. The residue was dissolved in DMF (0.5 mL) and was purified by prep-HPLC with the following conditions: [Column: XBridge Prep Phenyl OBD Column 19*250 mm, 5 pm; Mobile Phase A: Water (10 mmol/L NH4HCO3), Mobile Phase B: ACN; Flow rate: 20 mL/min; Gradient (B%): 44% B to 54% B in 15 min; Wave Length: 254/220 nm; RTl(min): 13] to afford ((3R,8R)-4-amino-3-methyl-l,3,6,7,8,9- hexahydrofuro[3,4-c][l,7]naphthyridin-8-yl)((3aR*,8bR*)-6-(trifluoromethyl)-2,3,3a,8b- tetrahydro-lH-benzofuro[3,2-b]pyrrol-l-yl)methanone, isomer 2 (Example 68) (13.2 mg, 32%) as a white solid. MS ESI calculated for C23H23F3N4O3 [M+H]⁺, 461.17; found, 461.15. ¹H NMR (400 MHz, DMSO-d₆) 57.72 (d, J = 7.8 Hz, 1H), 7.30 - 7.06 (m, 2H), 5.72 - 5.56 (m, 3H), 5.51 - 5.15 (m, 2H), 5.04 - 4.67 (m, 2H), 4.00 - 3.83 (m, 1H), 3.77 - 3.66 (m, 1H), 3.63 - 3.52 (m, 2H), 3.44 - 3.35 (m, 1H), 2.71 - 2.56 (m, 2H), 2.36 - 2.19 (m, 3H), 1.32 (d, J = 6.4 Hz, 3H).

Example 69: ((3R,8R)-4-amino-3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4- c][l,7]naphthyridin-8-yl)((4aS,9bS)-7-(trifluoromethoxy)-3,4,4a,9b-tetrahydrofuro[2,3- b:4,5-b']dipyridin-l(2H)-yl)methanone

A96

[1828] To a solution of intermediate CA6, isomer 3 (67.13 mg, 0.192 mmol), DIEA (49.67 mg, 0.384 mmol) in N,N-dimethylacetamide (5 mL) were added CMPI (98.18 mg, 0.384 mmol) and intermediate A96 (50 mg, 0.192 mmol). The resulting mixture was stirred at room temperature for Ih. The reaction mixture was quenched with water and the aqueous layer was extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous NaiSCL. After filtration, the filtrate was concentrated under vacuum. The residue was purified by silica gel column chromatography, eluted with 0-30% ethyl acetate in petroleum ether to afford tert-butyl (3R,8R)-4-amino-3-methyl-8-((4aS,9bS)-7- (trifhioromethoxy)-l,2,3,4,4a,9b-hexahydrofuro[2,3-b:4,5-b']dipyridine-l-carbonyl)-3,6,8,9- tetrahydrofuro[3,4-c][l,7]naphthyridine-7(lH)-carboxylate (60 mg, 52%) as a yellow oil. This product (60 mg, 0.101 mmol) was dissolved in HC1 (g) in 1,4-dioxane (4.0 M, 5 mL) and the mixture was stirred at room temperature for 1 h. The resulting mixture was concentrated under vacuum. The crude product was purified by Prep-HPLC with the following conditions: (Column: XBridge Prep OBD C18 Column 30*150 mm; Mobile Phase A: Water (10 mmol/L NH4HCO3), Mobile Phase B: ACN; Flow rate: 60 mL/min; Gradient (B%): 5% B to 5% B in 2 min, 33% B to 53% B in 10 min; Wave Length: 254/220 nm; RTl(min): 9.3) to afford ((3R,8R)-4-amino-3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4- c][l,7]naphthyridin-8-yl)((4aS,9bS)-7-(trifhioromethoxy)-3,4,4a,9b-tetrahydrofuro[2,3-b:4,5- b']dipyridin-l(2H)-yl)methanone (Example 69) (37 mg, 74%) as a white solid. MS ESI calculated for C23H24F₃N5O4 [M+H]⁺, 492.2; found, 492.15. ¹H NMR (400 MHz, DMSO-d₆) 57.71 (d, J = 7.6 Hz, IH), 6.83 (d, 7=7.6 Hz, 1H), 6.13 (t, J = 7.6Hz, 1H), 5.63 (d, J= 4.4 Hz, 2H), 5.22 (d, 7=4.2 Hz, 2H), 4.94 (t, 7 = 12.8Hz, IH), 4.78 (t, 7 = 13.6Hz, IH), 4.18 - 3.68 (m, 4H), 2.99 - 2.67 (m, 2H), 2.49 - 2.37 (m, 2H), 1.93 (t, 7=4.9 Hz, IH), 1.82 - 1.78 (m, IH), 1.72 - 1.42 (m, 2H), 1.31 (d, 7 = 6.4 Hz, 3H). Example 70: ((3R,8R)-4-amino-3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4-c][l,7]naphthyridin- 8-yl)((4aR*,9bR*)-7-isopropyl-3,4,4a,9b-tetrahydrofuro[2,3-b:4,5-b']dipyridin-l(2H)- yl)methanone

[1829] To a stirred solution of intermediate A75 (30 mg, 0.14 mmol) in N,N- dimethylacetamide (3 mL) were added intermediate CA6, isomer 3 (72 mg, 0.21 mmol), CMPI (53 mg, 0.21 mmol) and DIEA (53 mg, 0.41 mmol). The resulting solution was stirred at 25 °C for 1 h. The reaction mixture was quenched with water and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered through paper, and concentrated under vacuum. The residue was purified by silica gel column chromatography, eluted with 0 ~ 10% MeOH in DCM to afford tert-butyl (3R,8R)-4-amino-8-((4aR*,9bR*)-7-isopropyl-l,2,3,4,4a,9b-hexahydrofuro[2,3- b:4,5-b']dipyridine-l-carbonyl)-3-methyl-3,6,8,9-tetrahydrofuro[3,4-c][l,7]naphthyridine- 7(lH)-carboxylate (85 mg, 74%) as a yellow oil.

[1830] A mixture of tert-butyl (3R,8R)-4-amino-8-((4aR*,9bR*)-7-isopropyl-l,2,3,4,4a,9b- hexahydrofuro[2,3-b:4,5-b']dipyridine-l-carbonyl)-3-methyl-3,6,8,9-tetrahydrofuro[3,4- c][l,7]naphthyridine-7(lH)-carboxylate (80 mg, 0.010 mmol) and hydrogen chloride (4.0 M in ethyl acetate) (1 mL) was stirred at 25 °C for 0.5 h. The solvent was removed under vacuum. The crude residue was purified by prep-HPLC with the following conditions: [Column: XBridge Prep Phenyl OBD Column 19*250 mm, 5 pm; Mobile Phase A: Water (10 mmol/L NH4HCO3), Mobile Phase B: MeOH; Flow rate: 20 mL/min; Gradient (B%): 55% B to 65% B in 15 min; Wave Length: 254/220 nm; RTl(min): 15] to afford ((3R,8R)-4-amino- 3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4-c][l,7]naphthyridin-8-yl)((4aR*,9bR*)-7-isopropyl- 3,4,4a,9b-tetrahydrofuro[2,3-b:4,5-b']dipyridin-l(2H)-yl)methanone (Example 70) (22.6 mg, 34%) as a white solid. MS ESI calculated for C25H31N5O3 [M+H]⁺, 450.24; found 450.25. 'H NMR (400 MHz, DMSO-J₆) 8 7.78 - 7.36 (m, 1H), 6.92 - 6.71 (m, 1H), 6.16 - 5.94 (m, 1H), 5.62 (s, 2H), 5.23 - 5.21 (m, 1H), 5.08 - 4.88 (m, 2H), 4.83 - 4.72 (m, 1H), 4.18 - 3.84 (m, 2H), 3.74 - 3.70 (m, 2H), 2.96 - 2.88 (m, 1H), 2.76 - 2.59 (m, 2H), 2.47 - 2.35 (m, 2H), 1.98 - 1.72 (m, 3H), 1.66 - 1.45 (m, 1H), 1.31 (dd, J = 6.4, 1.2 Hz, 3H), 1.25 - 1.12 (m, 6H).

Example 71: ((3R,8R)-4-amino-3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4-c][l,7]naphthyridin- 8-yl)((4R*,4aS*,10bR*)-8-chloro-4-fluoro-2,3,4,4a,6,10b-hexahydro-lH-pyrano[3,2-b:5,4- b']dipyridin- l-yl)methanone

A47 isomer 1

[1831] Followed the procedure of Example 39 with intermediate A47 isomer 1 (40 mg, 0.17 mmol) and intermediate CA6 isomer 3 (75 mg, 0.22 mmol) to afford ((3R,8R)-4-amino- 3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4-c][l,7]naphthyridin-8-yl)((4R*,4aS*,10bR*)-8- chloro-4-fluoro-2,3,4,4a,6, 1 Ob-hexahydro- lH-pyrano[3,2-b:5,4-b']dipyridin- 1 -yl)methanone (Example 71) (14.6 mg, 44%) as a white solid. MS ESI calculated for C23H25CIFN5O3 [M+H]⁺, 474.16; found, 474.20. 'H NMR (400 MHz, DMSO- ₆) 8 (ppm) 7.76 - 7.36 (m, 2H), 5.84 - 5.59 (m, 3H), 5.30 - 5.06 (m, 2H), 5.03 - 4.87 (m, 2H), 4.83 - 4.73 (m, 2H), 4.39 - 3.91 (m, 3H), 3.85 - 3.58 (m, 2H), 3.00 - 2.64 (m, 4H), 2.22 - 2.00 (m, 1H), 1.93 - 1.80 (m, 1H), 1.32 (d, J = 5.6 Hz, 3H). Example 72: ((3R,8R)-4-amino-3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4- c][l,7]naphthyridin-8-yl)((4aS,6R,10bS)-8-(difluoromethoxy)-6-methyl-2,3,4,4a,6,10b- hexahydro- lH-isochromeno[4,3-b]pyridin- l-yl)methanone

A41 , isomer 3

[1832] To a stirred solution of intermediate A41, isomer 3 (70 mg, 0.260 mmol) and intermediate CA6, isomer 3 (91 mg, 0.260 mmol) in N,N-dimethylacetamide (3 mL) were added DIEA (99 mg, 0.766 mmol) and CMPI (126 mg, 0.493 mmol). The resulting mixture was stirred at room temperature for additional 1 h. The reaction mixture was quenched with water and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under vacuum to afford tertbutyl (3R,8R)-4-amino-8-((4aS,6R, 10bS)-8-(difluoromethoxy)-6-methyl-2,3,4,4a,6, 10b- hexahydro-lH-isochromeno[4,3-b]pyridine-l-carbonyl)-3-methyl-3,6,8,9-tetrahydrofuro[3,4- c][l,7]naphthyridine-7(lH)-carboxylate (50 mg, crude) as a yellow oil. This crude product (50 mg, 0.083 mmol) was dissolved in hydrogen chloride (4.0 M in ethyl acetate) (2 mL) and the resulting mixture was stirred at room temperature for 1 h. The solvents were removed under vacuum. The residue was dissolved in MeOH (2 mL) and was purified by prep-HPLC with the following conditions: [Column: XSelect CSH Prep Cl 8 OBD Column, 19*250 mm, 5 pm; Mobile Phase A: Water (lOmmol/L NH4HCO3), Mobile Phase B: MeOH; Flow rate: 20 mL/min; Gradient (B%): 69% B to 79% B in 16 min; Wave Length: 254/220 nm; RTl(min): 15] to afford ((3R,8R)-4-amino-3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4- c] [ 1 ,7]naphthyridin-8-yl)((4aS,6R, 10bS)-8-(difluoromethoxy)-6-methyl-2,3,4,4a,6, 10b- hexahydro-lH-isochromeno[4,3-b]pyridin-l-yl)methanone (Example 72) (5.3 mg, 15.90%) as a white solid. MS ESI calculated for C26H30F2N4O4 [M+H]⁺, 501.22; found, 501.15. ¹H NMR (400 MHz, CD3OD) 87.40 (d, J= 8.6 Hz, 1H), 7.15 - 6.64 (m, 3H), 5.59 (d, J= 6.0 Hz, 1H), 5.43 - 5.30 (m, 1H), 5.15 - 5.12 (m, 1H), 4.77 - 4.69 (m, 1H), 4.61 (s, 1H), 4.23 - 4.11 (m, 2H), 4.07 - 3.85 (m, 2H), 3.81 - 3.71 (m, 1H), 3.30 - 3.24 (m, 1H), 2.78 - 2.61 (m, 2H), 1.99 - 1.70 (m, 4H), 1.62 (d, J = 6.5 Hz, 3H), 1.43 (d, J = 6.2 Hz, 3H).

Example 73: ((3R,8R)-4-amino-3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4-c][l,7]naphthyridin- 8-yl)((3R,4aR*,10bR*)-3-methoxy-8-(trifluoromethyl)-2,3,4,4a,6,10b-hexahydro-lH- pyrano[3,2-b:5,4-b']dipyridin- 1 -yl)methanone

[1833] To a mixture of intermediate A97 (50 mg, 0.15 mmol), DIEA (59.88 mg, 0.46 mmol) and CMPI (78.92 mg, 0.308 mmol) in N,N-dimethylacetamide (0.5 mL) was added intermediate CA6, isomer 3 (64.75 mg, 0.18 mmol) at room temperature. The mixture was stirred at 40°C for 2h. The reaction mixture was quenched with water and the aqueous layer was extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SO4. After filtration, the filtrate was concentrated under vacuum. The residue was purified by silica gel column chromatography, eluted with 0-30% MeOH in CH2CI2 to afford tert-butyl (3R,8R)-4-amino-8-((3R,4aR*,10bR*)-3-methoxy-8-(trifluoromethyl)- 2,3,4,4a,6,10b-hexahydro-lH-pyrano[3,2-b:5,4-b']dipyridine-l-carbonyl)-3-methyl-3,6,8,9- tetrahydrofuro[3,4-c][l,7]naphthyridine-7(lH)-carboxylate (30 mg, 31 %) as a yellow oil. This product (30 mg, 0.04 mmol) was dissolved in HC1 (g) in 1,4-dioxane (4.0 M, 5 mL) and the mixture was stirred at room temperature for additional 1 h. The resulting mixture was concentrated under vacuum. The crude product (60 mg) was purified by Prep-HPLC with the following conditions: (Column: XB ridge Prep Phenyl OBD Column 19*250 mm, 5 pm; Mobile Phase A: Water (10 mmol/L NH4HCO3), Mobile Phase B: ACN; Flow rate: 20 mL/min; Gradient (B%): 53% B to 63% B in 15 min; Wave Length: 254/220 nm; RTl(min): 15) to afford ((3R,8R)-4-amino-3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4-c][l,7]naphthyridin- 8-yl)((3R,4aR*, 10bR*)-3-methoxy-8-(trifluoromethyl)-2,3,4,4a,6, lOb-hexahydro- 1H- pyrano[3,2-b:5,4-b']dipyridin-l-yl)methanone (Example 73) (3.9 mg, 15%) as a yellow solid. MS ESI calculated for C25H28F3N5O4 [M+H]⁺, 520.21; found, 520.21.¹H NMR (400 MHz, DMSO-d₆) 5 8.04 - 7.70 (m, 2H), 5.89 - 5.56 (m, 3H), 5.25 - 5.23 (m, 1H), 5.10 - 4.69 (m, 4H), 4.41 (d, J= 14.8 Hz, 1H), 4.16 (s, 1H), 3.97 - 3.86 (m, 2H), 3.57 - 3.46 (m, 1H), 3.29 - 3.26 (m, 5H), 2.88 - 2.72 (m, 1H), 2.24 - 2.20 (m, 3H), 1.58 - 1.50 (m, 1H), 1.37 - 1.14 (m, 3H).

Example 74: ((3R,8R)-4-amino-3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4-c][l,7]naphthyridin-

8-yl)((4aR*,9bR*)-7-methoxy-3,4,4a,9b-tetrahydrobenzofuro[3,2-b]pyridin-l(2H)- yl)methanone [1834] To a solution of intermediate A58, isomer 1 (50 mg, 0.244 mmol), intermediate CA6, isomer 3 (85.11 mg, 0.244 mmol), DIEA (63 mg, 0.488 mmol) in N,N- dimethylacetamide (3 mL) was added CMPI (125 mg, 0.488 mmol). The resulting mixture was stirred at room temperature for Ih. The reaction mixture was quenched with water and the aqueous layer was extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SC>4. After filtration, the filtrate was concentrated under vacuum. The residue was purified by silica gel column chromatography, eluted with 0-30% ethyl acetate in petroleum ether to afford tert-butyl (3R,8R)-4-amino-8-((4aR*,9bR*)-7- methoxy-l,2,3,4,4a,9b-hexahydrobenzofuro[3,2-b]pyridine-l-carbonyl)-3-methyl-3,6,8,9- tetrahydrofuro[3,4-c][l,7]naphthyridine-7(lH)-carboxylate (60 mg, 45%) as a yellow oil. This product (60 mg, 0.112 mmol) was dissolved in HC1 (g) in dioxane (4 M, 3 mL) and the resulting mixture was stirred at room temperature for Ih. The resulting mixture was concentrated under vacuum. The crude product (35mg) was purified by Prep-HPLC with the following conditions: (Column: XB ridge Prep Phenyl OBD Column 19*250 mm, 5 pm; Mobile Phase A: Water (10 mmol/L NH4HCO3), Mobile Phase B: MeOH; Flow rate: 20 mL/min; Gradient (B%): 62% B to 72% B in 15 min; Wave Length: 254/220 nm; RTl(min): 15) to afford ((3R,8R)-4-amino-3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4-c][l,7]naphthyridin- 8-yl)((4aR*,9bR*)-7-methoxy-3,4,4a,9b-tetrahydrobenzofuro[3,2-b]pyridin-l(2H)- yl)methanone (Example 74) (16.5 mg, 33%) as a white solid. MS ESI calculated for C24H28N4O4 [M+H]⁺, 437.20; found, 437.15. 'H NMR (400 MHz, DMSO-d₆) 6 7.93 (t, J = 5.6 Hz, 1H), 7.39 (d, 7= 8.4 Hz, IH), 7.11 (d, 7= 2.4 Hz, IH), 6.82 (d, J= 8.4Hz, 1H), 6.51 (s, IH), 5.61 (s, 2H), 5.22 - 5.20 (m, IH), 4.96 - 4.92 (m, IH), 4.78 (d, J = 13.6 Hz, IH), 3.78 (s, 3H), 3.72 - 3.68 (m, 2H), 3.43 - 3.33 (m, 2H), 3.25 - 3.14 (m, 2H), 2.74 (t, 7 = 7.6 Hz, 2H), 2.64 - 2.57 (m, 2H), 1.84 - 1.82 (m, 2H), 1.32 (d, 7 = 6.1 Hz, 3H).

Example 75: ((3R,8R)-4-amino-3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4-c][l,7]naphthyridin- 8-yl)((4R* ,4aS* , 10bR*)-4-methoxy-8-(trifluoromethyl)-2,3 ,4, 4a, 6, 1 Ob-hexahydro- 1 H- pyrano[3,2-b:5,4-b']dipyridin- 1 -yl)methanone

[1835] To a stirred solution of intermediate A98 isomer 1 (40 mg, 0.14 mmol) and intermediate CA6, isomer 3 (49 mg, 0.14 mmol) in N,N-dimethylacetamide (1.5 mL) were added DIEA (90 mg, 0.70 mmol) and CMPI (53 mg, 0.21 mmol). The resulting mixture was stirred at room temperature for 4 h under nitrogen atmosphere. The reaction mixture was purified by reverse phase flash column chromatography on a 25 g Cl 8 column with 5-60% acetonitrile in water (10 mM NH4HCO3) to afford tert-butyl (3R,8R)-4-amino-8- ((4R*,4aS*,10bR*)-4-methoxy-8-(trifluoromethyl)-2,3,4,4a,6,10b-hexahydro-lH-pyrano[3,2- b :5 ,4-b']dipyridine- 1 -carbonyl)-3-methyl-3 ,6,8 ,9-tetrahydrofuro [3 ,4-c] [ 1 ,7]naphthyridine- 7(lH)-carboxylate (30 mg, 35%) as a white solid. This product (30 mg, 0.05 mmol) was dissolved in HC1 in 1,4-dioxane (4.0 M) (1 mL) and the resulting mixture was stirred at room temperature for 2 h under nitrogen atmosphere. The resulting mixture was concentrated under vacuum. The residue was dissolved in MeCN (1.5 mL) and was purified by Prep-HPLC with the following conditions: [Column: XBridge Prep Phenyl OBD Column 19*250 mm, 5pm; Mobile Phase A: Water (10 mmol/L NH4HCO3), Mobile Phase B: ACN; Flow rate: 20 mL/min; Gradient (B%): 34% B to 49% B in 12 min; Wave Length: 254/220 nm; RTl(min): 12] to afford ((3R,8R)-4-amino-3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4-c][l,7]naphthyridin- 8-yl)((4R*,4aS*,10bR*)-4-methoxy-8-(trifluoromethyl)-2,3,4,4a,6,10b-hexahydro-lH- pyrano[3,2-b:5,4-b']dipyridin-l-yl)methanone (13.2 mg, 80% de), which was further purified by Prep-Chiral HPLC with the following conditions: [Column: CHIRALPAK IB, 2*25 cm, 5 pm; Mobile Phase A: Hex (0.5% 2M NH₃-MeOH)-HPLC, Mobile Phase B: MeOH: DCM=1: 1— HPLC; Flow rate: 20 mL/min; Gradient (B%): isocratic 35% B to 35% in lOmin; Wave Length: 220/254 nm; RTl(min): 4.74; RT2(min): 8.74; Sample Solvent: MeOH: DCM=1: 1-HPLC; Injection Volume: 1.5 mL; Number Of Runs: 1] to afford ((3R,8R)-4- amino-3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4-c][l,7]naphthyridin-8-yl)((4R*,4aS*,10bR*)- 4-methoxy-8-(trifluoromethyl)-2,3 ,4, 4a, 6, 1 Ob-hexahydro- 1 H-pyrano [3 ,2-b : 5 ,4-b '] dipyridin- l-yl)methanone (Example 75) (7.9 mg, 31%) as a white solid with retention time at 8.74 minute. MS ESI calculated for C25H28F3N5O4 [M+H]⁺, 520.21; found, 520.25. NMR (300 MHz, DMSO-d₆) 87.90 (d, J= 8.1 Hz, 1H), 7.80 (d, J= 8.1 Hz, 1H), 5.61 (s, 3H), 5.23 (d, J = 7.5 Hz, 1H), 5.08 - 4.88 (m, 2H), 4.82 - 4.71 (m, 2H), 4.29 (d, J = 6.0 Hz, 1H), 4.04 - 4.01 (m, 1H), 3.92 - 3.86 (m, 1H), 3.84 - 3.77 (m, 2H), 3.58 - 3.55 (m, 1H), 3.22 - 3.08 (m, 4H), 2.84 - 2.62 (m, 2H), 2.48 - 2.37 (m, 1H), 2.33 - 2.30 (m, 1H), 1.69 - 1.65 (m, 1H), 1.32 (d, J = 6.0 Hz, 3H).

Example 76: ((3R,8R)-4-amino-3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4- c][l,7]naphthyridin-8-yl)((3R,4aS,9bS)-7-(difluoromethoxy)-3-methyl-3,4,4a,9b- tetrahydrofuro[2,3-b:4,5-b']dipyridin- 1 (2H)-yl)methanone

A99, isomer 1

[1836] Followed the procedure of Example 39 with intermediate CA6, isomer 3 (60 mg, 0.17 mmol) and intermediate A99 isomer 1 (53 mg, 0.21 mmol) to afford ((3R,8R)-4-amino- 3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4-c][l,7]naphthyridin-8-yl)((3R,4aS,9bS)-7- (difluoromethoxy )-3-methyl-3, 4,4a, 9b-tetrahydrofuro[2,3-b:4,5-b']dipyridin-l(2H)- yl)methanone (Example 76) (21.9 mg, 27%) as a white solid. MS ESI calculated for C24H27F2N5O4 [M+H]⁺, 488.20; found,488.25. 'H NMR (400 MHz, DMSO-d₆) 87.97 - 7.35 (m, 2H), 6.66 and 6.60 (d, J = 7.9 Hz, 1H), 6.03 and 5.97 (d, J= 8.5 Hz, 1H), 5.63 (s, 2H), 5.27 - 5.17 (m, 1H), 5.14 - 5.03 (m, 1H), 4.99 - 4.89 (m, 1H), 4.83 - 4.71 (m, 1H), 4.35 - 3.91 (m, 2H), 3.85 - 3.63 (m, 2H), 2.79 - 2.61 (m, 1H), 2.49 - 2.30 (m, 2H), 2.16 - 2.02 (m, 1H), 1.96 - 1.85 (m, 1H), 1.78 - 1.65 (m, 1H), 1.54 - 1.37 (m, 1H), 1.35 - 1.27 (m, 3H), 0.95 - 0.85

Example 77: ((3R,8R)-4-amino-3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4- c][l,7]naphthyridin-8-yl)((3S,4aS,9bS)-7-(difluoromethoxy)-3-methyl-3,4,4a,9b- tetrahydrofuro[2,3-b:4,5-b']dipyridin-l(2H)-yl)methanone

A99, isomer 2

[1837] Followed the procedure of Example 39 with intermediate CA6, isomer 3 (50 mg, 0.14 mmol) and intermediate A99 isomer 2 (36 mg, 0.14 mmol) to afford ((3R,8R)-4-amino- 3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4-c][l,7]naphthyridin-8-yl)((3S,4aS,9bS)-7- (difluoromethoxy)-3-methyl-3,4,4a,9b-tetrahydrofuro[2,3-b:4,5-b']dipyridin-l(2H)- yl)methanone formate (Example 77) (8.6 mg, 13%) as a white solid. MS ESI calculated for C24H27F2N5O4 [M+H]⁺, 488.20; found, 488.25. 'H NMR (400 MHz, DMSO-d₆) 88.17 (s, 1H), 8.05 - 7.35 (m, 2H), 6.63 - 6.53 (m, 1H), 6.05 - 6.15 (m, 1H), 5.63 (s, 2H), 5.34 - 5.16 (m, 2H), 5.04 - 4.87 (m, 1H), 4.82 - 4.71 (m, 1H), 4.25 - 3.93 (m, 1H), 3.96 - 3.67 (m, 2H), 3.78 - 3.50 (m, 1H), 3.26 - 3.24 (m, 1H), 2.83 - 2.69 (m, 1H), 2.70 - 2.58 (m, 1H), 2.48 - 2. 44 (m, 1H), 2.09 - 1.92 (m, 1H), 1.87 - 1.75 (m, 1H), 1.58 - 1.36 (m, 1H), 1.39 - 1.32 (m, 3H), 1.18 - 0.89 (m, 3H).

Example 78: ((3R*,8S*)-4-amino-3-methyl-3,6,8,9-tetrahydro-lH-furo[3,4-d]pyrano[3,4- b]pyridin-8-yl)((4aS,9bS)-7-(trifluoromethyl)-3,4,4a,9b-tetrahydrofuro[2,3-b:4,5- b']dipyridin-l(2H)-yl)methanone isomer 1

Example 79: ((3R*,8S*)-4-amino-3-methyl-3,6,8,9-tetrahydro-lH-furo[3,4-d]pyrano[3,4- b]pyridin-8-yl)((4aS,9bS)-7-(trifluoromethyl)-3,4,4a,9b-tetrahydrofuro[2,3-b:4,5- b']dipyridin-l(2H)-yl)methanone isomer 2

Example 80: ((3R*,8S*)-4-amino-3-methyl-3,6,8,9-tetrahydro-lH-furo[3,4-d]pyrano[3,4- b]pyridin-8-yl)((4aS,9bS)-7-(trifluoromethyl)-3,4,4a,9b-tetrahydrofuro[2,3-b:4,5- b']dipyridin-l(2H)-yl)methanone isomer 3 Example 81: ((3R*,8S*)-4-amino-3-methyl-3,6,8,9-tetrahydro-lH-furo[3,4-d]pyrano[3,4- b]pyridin-8-yl)((4aS,9bS)-7-(trifluoromethyl)-3,4,4a,9b-tetrahydrofuro[2,3-b:4,5- b']dipyridin-l(2H)-yl)methanone isomer 4

[1838] To a stirred solution of intermediate CA12 (50 mg, 0.10 mmol) and A26 isomer 1 (31 mg, 0.12 mmol) in DMAC (3 mL) were added DIEA (41 mg, 0.31 mmol) and CMPI (40 mg, 0.15 mmol) at room temperature. The resulting mixture was stirred at room temperature for 1 h. The resulting mixture was diluted with water and extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SO4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-70% ethyl acetate in petroleum ether to afford a 1: 1:1:1 mixture of tert-butyl (4-methoxybenzyl)((3R,8S)-3-methyl-8-((4aS,9bS)-7- (trifhioromethyl)-l,2,3,4,4a,9b-hexahydrofuro[2,3-b:4,5-b']dipyridine-l-carbonyl)-3,6,8,9- tetrahydro-lH-furo[3,4-d]pyrano[3,4-b]pyridin-4-yl)carbamate and tert-butyl (4- methoxybenzyl)((3R,8R)-3-methyl-8-((4aS,9bS)-7-(trifluoromethyl)-l,2,3,4,4a,9b- hexahydrofuro[2,3-b:4,5-b']dipyridine-l-carbonyl)-3,6,8,9-tetrahydro-lH-furo[3,4- d]pyrano[3,4-b]pyridin-4-yl)carbamate and tert-butyl (4-methoxybenzyl)((3S,8S)-3-methyl- 8-((4aS,9bS)-7-(trifluoromethyl)-l,2,3,4,4a,9b-hexahydrofuro[2,3-b:4,5-b']dipyridine-l- carbonyl)-3,6,8,9-tetrahydro- lH-furo[3,4-d]pyrano[3,4-b]pyridin-4-yl)carbamate and tertbutyl (4-methoxybenzyl)((3S,8R)-3-methyl-8-((4aS,9bS)-7-(trifluoromethyl)- 1 ,2,3,4,4a,9b- hexahydrofuro[2,3-b:4,5-b']dipyridine-l-carbonyl)-3,6,8,9-tetrahydro-lH-furo[3,4- d]pyrano[3,4-b]pyridin-4-yl)carbamate (50 mg, 67%) as a colorless oil. MS ESI calculated for C36H39F3N4O7 [M+H]⁺, 697.28; found, 697.15.

Step-2:

[1839] A solution of a 1: 1 : 1 : 1 mixture of tert-butyl (4-methoxybenzyl)((3R,8S)-3-methyl-

8-((4aS,9bS)-7-(trifluoromethyl)-l,2,3,4,4a,9b-hexahydrofuro[2,3-b:4,5-b']dipyridine-l- carbonyl)-3,6,8,9-tetrahydro- lH-furo[3,4-d]pyrano[3,4-b]pyridin-4-yl)carbamate and tertbutyl (4-methoxybenzyl)((3R,8R)-3-methyl-8-((4aS,9bS)-7-(trifluoromethyl)-l,2,3,4,4a,9b- hexahydrofuro[2,3-b:4,5-b']dipyridine-l-carbonyl)-3,6,8,9-tetrahydro-lH-furo[3,4- d]pyrano[3,4-b]pyridin-4-yl)carbamate and tert-butyl (4-methoxybenzyl)((3S,8S)-3-methyl- 8-((4aS,9bS)-7-(trifluoromethyl)-l,2,3,4,4a,9b-hexahydrofuro[2,3-b:4,5-b']dipyridine-l- carbonyl)-3,6,8,9-tetrahydro- lH-furo[3,4-d]pyrano[3,4-b]pyridin-4-yl)carbamate and tertbutyl (4-methoxybenzyl)((3S,8R)-3-methyl-8-((4aS,9bS)-7-(trifluoromethyl)- 1 ,2, 3, 4, 4a, 9b- hexahydrofuro[2,3-b:4,5-b']dipyridine-l-carbonyl)-3,6,8,9-tetrahydro-lH-furo[3,4- d]pyrano[3,4-b]pyridin-4-yl)carbamate (50 mg, 0.07 mmol) in TFA (2 mL) was stirred at 50 °C for 1 h. The mixture was allowed to cool down to room temperature and concentrated under vacuum. The reaction solution was purified by reverse phase flash column chromatography with 5% to 60% MeCN in Water (0.1% TFA) to afford a 1 : 1: 1 : 1 mixture of ((3R,8S)-4-amino-3-methyl-3,6,8,9-tetrahydro-lH-furo[3,4-d]pyrano[3,4-b]pyridin-8- yl)((4aS,9bS)-7-(trifluoromethyl)-3,4,4a,9b-tetrahydrofuro[2,3-b:4,5-b^,]dipyridin-l(2H)- yl)methanone, ((3R,8R)-4-amino-3-methyl-3,6,8,9-tetrahydro-lH-furo[3,4-d]pyrano[3,4- b]pyridin-8-yl)((4aS,9bS)-7-(trifhioromethyl)-3,4,4a,9b-tetrahydrofuro[2,3-b:4,5- b']dipyridin-l(2H)-yl)methanone, ((3S,8S)-4-amino-3-methyl-3,6,8,9-tetrahydro-lH- furo[3,4-d]pyrano[3,4-b]pyridin-8-yl)((4aS,9bS)-7-(trifluoromethyl)-3,4,4a,9b- tetrahydrofuro[2,3-b:4,5-b']dipyridin-l(2H)-yl)methanone and ((3S,8R)-4-amino-3-methyl- 3,6,8,9-tetrahydro-lH-furo[3,4-d]pyrano[3,4-b]pyridin-8-yl)((4aS,9bS)-7-(trifluoromethyl)- 3,4,4a,9b-tetrahydrofuro[2,3-b:4,5-b']dipyridin-l(2H)-yl)methanone (32 mg, 93%) as a white solid.

[1840] The mixture (32 mg) was separated by Prep-Chiral-HPLC with the following conditions: [Column: CHIRALPAK IB, 2*25 cm, 5 pm; Mobile Phase A: Hex(0.5% 2M NH₃-MeOH)-HPLC, Mobile Phase B: MeOH: DCM=1: 1-HPLC; Flow rate: 20 mL/min; Gradient (B%): isocratic 35% B to 35% in 10.5min% B; Wave Length: 220/254 nm; RTl(min): 7.31; RT2(min): 7.81; RT3(min): 8.29; RT4(min): 9.28; Sample Solvent: MeOH: DCM=1: 1-HPLC; Injection Volume: 0.3 mL; Number Of Runs: 7] to afford ((3R*,8S*)-4- amino-3-methyl-3,6,8,9-tetrahydro-lH-furo[3,4-d]pyrano[3,4-b]pyridin-8-yl)((4aS,9bS)-7- (trifhioromethyl)-3,4,4a,9b-tetrahydrofuro[2,3-b:4,5-b']dipyridin-l(2H)-yl)methanone isomer 1 (Example 78) (6.0 mg, 18%) as a white solid with retention time at 7.31 minute. MS ESI calculated for C23H23F3N4O4 [M+H]⁺, 477.17; found, 477.25. 'H NMR (400 MHz, DMSO- d₆) 88.02 and 7.71 (d, J = 7.2 Hz, 1H), 7.41 - 7.50 (m, 1H), 6.22 and 6.13 (d, J = 9.2 Hz, 1H), 5.76 (s, 2H), 5.36 - 5.13 (m, 2H), 5.04 - 4.92 (m, 1H), 4.92 - 4.44 (m, 4H), 4.19 - 3.79 (m, 1H), 3.07 - 2.90 (m, 2H), 2.46 - 2.40 (m, 1H), 1.98 - 1.42 (m, 4H), 1.36 - 1.30 (m, 3H).

[1841] The separation also affords ((3R*,8S*)-4-amino-3-methyl-3,6,8,9-tetrahydro-lH- furo[3,4-d]pyrano[3,4-b]pyridin-8-yl)((4aS,9bS)-7-(trifluoromethyl)-3,4,4a,9b- tetrahydrofuro[2,3-b:4,5-b']dipyridin-l(2H)-yl)methanone isomer 2 (Example 79) (6.6 mg, 20%) as a white solid with retention time at 7.81 minute. MS ESI calculated for C23H23F3N4O4 [M+H]⁺, 477.17; found, 477.25. ’H NMR (400 MHz, DMSO-d₆) 87.95 and 7.79 (d, 7 = 7.2 Hz, 1H), 7.50 - 7.42 (m, 1H), 6.16 and 6.03 (d, J = 9.2 Hz, 1H), 5.80 - 5.71 (m, 2H), 5.30 - 5.16 (m, 2H), 5.03 - 4.94 (m, 1H), 4.91 - 4.49 (m, 4H), 4.20 - 3.81 (m, 1H), 3.06 - 2.84 (m, 2H), 2.48 - 2.41 (m, 1H), 2.04 - 1.45 (m, 4H), 1.37 - 1.30 (m, 3H).

[1842] The separation also affords ((3R*,8S*)-4-amino-3-methyl-3,6,8,9-tetrahydro-lH- furo[3,4-d]pyrano[3,4-b]pyridin-8-yl)((4aS,9bS)-7-(trifluoromethyl)-3,4,4a,9b- tetrahydrofuro[2,3-b:4,5-b']dipyridin-l(2H)-yl)methanone isomer 3 (Example 80) (2.2 mg, 6%) as a white solid with retention time at 8.29 minute. MS ESI calculated for C23H23F3N4O4 [M+H]⁺, 477.17; found, 477.15. 'H NMR (400 MHz, DMSO-7₆) 87.94 and 7.79 (d, J = 7.2 Hz, 1H), 7.52 - 7.41 (m, 1H), 6.16 and 6.03 (d, J = 9.2 Hz, 1H), 5.80 - 5.71 (m, 2H), 5.30 - 5.11 (m, 2H), 5.07 - 4.42 (m, 5H), 4.19 - 3.75 (m, 1H), 3.02 - 2.86 (m, 2H), 2.36 - 2.22 (m, 1H), 1.94 - 1.50 (m, 4H), 1.37 - 1.30 (m, 3H).

[1843] The separation also affords ((3R*,8S*)-4-amino-3-methyl-3,6,8,9-tetrahydro-lH- furo[3,4-d]pyrano[3,4-b]pyridin-8-yl)((4aS,9bS)-7-(trifluoromethyl)-3,4,4a,9b- tetrahydrofuro[2,3-b:4,5-b']dipyridin-l(2H)-yl)methanone isomer 4 (Example 81) (2.7 mg, 6%) as a white solid with retention time at 9.28 minute. MS ESI calculated for C23H23F3N4O4 [M+H]⁺, 477.17; found, 477.25. 'H NMR (400 MHz, DMSO- fe) 88.02 and 7.71 (d, J = 7.2 Hz, 1H), 7.41 - 7.50 (m, 1H), 6.22 and 6.14 (d, J = 9.2 Hz, 1H), 5.97 (s, 2H), 5.36 - 5.15 (m, 2H), 5.08 - 4.81 (m, 2H), 4.77 - 4.44 (m, 3H), 4.18 - 3.81 (m, 1H), 3.08 - 2.87 (m, 2H), 2.62

- 2.54 (m, 1H), 1.97 - 1.43 (m, 4H), 1.35 (d, J = 6.4 Hz, 3H).

Example 82: rel-((3R,8S)-4-amino-3-methyl-3,6,8,9-tetrahydro-lH-furo[3,4-d]pyrano[3,4- b]pyridin-8-yl)((4aS,6R,10bS)-6-methyl-8-(trifluoromethyl)-2,3,4,4a,6,10b-hexahydro-lH- pyrano[3,2-b:5,4-b']dipyridin-l-yl)methanone isomer 1 Example 83: rel-((3R,8S)-4-amino-3-methyl-3,6,8,9-tetrahydro-lH-furo[3,4-d]pyrano[3,4- b]pyridin-8-yl)((4aS,6R,10bS)-6-methyl-8-(trifluoromethyl)-2,3,4,4a,6,10b-hexahydro-lH- pyrano[3,2-b:5,4-b']dipyridin-l-yl)methanone isomer 2

Isomer 2 and,

Example 84: rel-((3R,8S)-4-amino-3-methyl-3,6,8,9-tetrahydro-lH-furo[3,4-d]pyrano[3,4- b]pyridin-8-yl)((4aS,6R,10bS)-6-methyl-8-(trifluoromethyl)-2,3,4,4a,6,10b-hexahydro-lH- pyrano[3,2-b:5,4-b']dipyridin-l-yl)methanone isomer 3

Example 85: rel-((3R,8S)-4-amino-3-methyl-3,6,8,9-tetrahydro-lH-furo[3,4-d]pyrano[3,4- b]pyridin-8-yl)((4aS,6R,10bS)-6-methyl-8-(trifluoromethyl)-2,3,4,4a,6,10b-hexahydro-lH- pyrano[3,2-b:5,4-b']dipyridin-l-yl)methanone isomer 4

Isomer 4

Step-1:

[1844] To a stirred solution of intermediate CA12 (85 mg, 0.18 mmol), intermediate A45 isomer 1 (66 mg, 0.21 mmol) and DIEA (93.39 mg, 0.72 mmol) in DMAC (4 mL) was added CMPI (69.23 mg, 0.27 mmol) at room temperature. The resulting mixture was stirred at room temperature for 1 h. The resulting mixture was diluted with water. The resulting mixture was extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous NaiSt After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-38% EtOAc in PE to afford a 1:1:1 :1 mixture of tert-butyl (4-methoxybenzyl)((3R,8S)-3-methyl-8- ((4aS*,6R*,10bS*)-6-methyl-8-(trifluoromethyl)-2,3,4,4a,6,10b-hexahydro-lH-pyrano[3,2- b:5,4-b']dipyridine-l-carbonyl)-3,6,8,9-tetrahydro-lH-furo[3,4-d]pyrano[3,4-b]pyridin-4- yl)carbamate, tert-butyl (4-methoxybenzyl)((3R,8R)-3-methyl-8-((4aS*,6R*,10bS*)-6- methyl-8-(trifluoromethyl)-2,3,4,4a,6,10b-hexahydro-lH-pyrano[3,2-b:5,4-b']dipyridine-l- carbonyl)-3,6,8,9-tetrahydro-lH-furo[3,4-d]pyrano[3,4-b]pyridin-4-yl)carbamate, tert-butyl (4-methoxybenzyl)((3S,8S)-3-methyl-8-((4aS*,6R*,10bS*)-6-methyl-8-(trifluoromethyl)- 2,3,4,4a,6,10b-hexahydro-lH-pyrano[3,2-b:5,4-b']dipyridine-l-carbonyl)-3,6,8,9-tetrahydro- lH-furo[3,4-d]pyrano[3,4-b]pyridin-4-yl)carbamate and tert-butyl (4- methoxybenzyl)((3S,8R)-3-methyl-8-((4aS*,6R*,10bS*)-6-methyl-8-(trifluoromethyl)- 2,3,4,4a,6,10b-hexahydro-lH-pyrano[3,2-b:5,4-b']dipyridine-l-carbonyl)-3,6,8,9-tetrahydro- lH-furo[3,4-d]pyrano[3,4-b]pyridin-4-yl)carbamate (93 mg, 71%) as a white solid. MS ESI calculated for C38H43F3N4O7 [M+H]⁺, 725.31; found, 725.25.

Step-2:

[1845] A solution of 1 : 1 : 1 : 1 mixture of tert-butyl (4-methoxybenzyl)((3R,8S)-3-methyl-8- ((4aS*,6R*,10bS*)-6-methyl-8-(trifluoromethyl)-2,3,4,4a,6,10b-hexahydro-lH-pyrano[3,2- b:5,4-b']dipyridine-l-carbonyl)-3,6,8,9-tetrahydro-lH-furo[3,4-d]pyrano[3,4-b]pyridin-4- yl)carbamate, tert-butyl (4-methoxybenzyl)((3R,8R)-3-methyl-8-((4aS*,6R*,10bS*)-6- methyl-8-(trifluoromethyl)-2,3,4,4a,6,10b-hexahydro-lH-pyrano[3,2-b:5,4-b']dipyridine-l- carbonyl)-3,6,8,9-tetrahydro-lH-furo[3,4-d]pyrano[3,4-b]pyridin-4-yl)carbamate, tert-butyl (4-methoxybenzyl)((3S,8S)-3-methyl-8-((4aS*,6R*,10bS*)-6-methyl-8-(trifluoromethyl)- 2,3,4,4a,6,10b-hexahydro-lH-pyrano[3,2-b:5,4-b']dipyridine-l-carbonyl)-3,6,8,9-tetrahydro- lH-furo[3,4-d]pyrano[3,4-b]pyridin-4-yl)carbamate and tert-butyl (4- methoxybenzyl)((3S,8R)-3-methyl-8-((4aS*,6R*,10bS*)-6-methyl-8-(trifluoromethyl)- 2,3,4,4a,6,10b-hexahydro-lH-pyrano[3,2-b:5,4-b']dipyridine-l-carbonyl)-3,6,8,9-tetrahydro- lH-furo[3,4-d]pyrano[3,4-b]pyridin-4-yl)carbamate (85 mg, 0.11 mmol) in TFA (3 mL) was stirred at 50 °C for 2 h under nitrogen atmosphere. The mixture was allowed to cool down to room temperature. The resulting mixture was concentrated under reduced pressure. The residue was purified by reversed-phase flash column chromatography with 5% to 40% MeCN in Water (0.1% TFA) to afford a 1: 1: 1: 1 mixture of ((3R,8S)-4-amino-3-methyl-3,6,8,9- tetrahydro-lH-furo[3,4-d]pyrano[3,4-b]pyridin-8-yl)((4aS*,6R*,10bS*)-6-methyl-8- (trifluoromethyl)-2,3,4,4a,6, 1 Ob-hexahydro- 1 H-pyrano [3 ,2-b :5 ,4-b'] dipyridin- 1 - yl)methanone and ((3R,8R)-4-amino-3-methyl-3,6,8,9-tetrahydro- lH-furo[3,4-d]pyrano[3,4- b]pyridin-8-yl)((4aS*,6R*,10bS*)-6-methyl-8-(trifluoromethyl)-2,3,4,4a,6,10b-hexahydro- lH-pyrano[3,2-b:5,4-b']dipyridin-l-yl)methanone and ((3S,8S)-4-amino-3-methyl-3,6,8,9- tetrahydro-lH-furo[3,4-d]pyrano[3,4-b]pyridin-8-yl)((4aS*,6R*,10bS*)-6-methyl-8- (trifluoromethyl)-2,3,4,4a,6, 1 Ob-hexahydro- 1 H-pyrano [3 ,2-b :5 ,4-b'] dipyridin- 1 - yl)methanone and ((3S,8R)-4-amino-3-methyl-3,6,8,9-tetrahydro-lH-furo[3,4-d]pyrano[3,4- b]pyridin-8-yl)((4aS*,6R*,10bS*)-6-methyl-8-(trifluoromethyl)-2,3,4,4a,6,10b-hexahydro- lH-pyrano[3,2-b:5,4-b']dipyridin-l-yl)methanone (39 mg, 65%) as a white solid.

[1846] The mixture (39 mg) was separated by Prep-Chiral HPLC with the following conditions:[ Column: CHIRALPAK IG, 2*25 cm, 5 pm; Mobile Phase A: Hex(0.5% 2M NH3-MeOH)— HPLC, Mobile Phase B: MeOH: DCM=1: 1-HPLC; Flow rate: 20 mL/min; Gradient (B%): 30% B to 30% B in 35 min% B; Wave Length: 220/254 nm; RTl(min): 10.37; RT2(min): 12.586; RT3(min): 15.343; RT4(min): 23.63;Sample Solvent: MeOH: DCM=1: 1— HPLC; Injection Volume: 1.0 mL; Number Of Runs: 3] to afford rel-((3R,8S)-4- amino-3-methyl-3,6,8,9-tetrahydro-lH-furo[3,4-d]pyrano[3,4-b]pyridin-8-yl)((4aS,6R,10bS)- 6-methyl-8-(trifluoromethyl)-2,3,4,4a,6,10b-hexahydro-lH-pyrano[3,2-b:5,4-b']dipyridin-l- yl)methanone isomer 1 (Example 82) (4.1 mg, 10%) as a white solid with retention time at 10.37 minute.

[1847] The chiral resolution also affords rel-((3R,8S)-4-amino-3-methyl-3,6,8,9- tetrahydro-lH-furo[3,4-d]pyrano[3,4-b]pyridin-8-yl)((4aS,6R,10bS)-6-methyl-8- (trifhioromethyl)-2,3,4,4a,6, 1 Ob-hexahydro- 1 H-pyrano [3 ,2-b :5 ,4-b'] dipyridin- 1 - yl)methanone isomer 2 (Example 83) (5.2 mg, 13%) as a white solid with retention time at 12.586 minute.

[1848] The chiral resolution also afford rel-((3R,8S)-4-amino-3-methyl-3,6,8,9-tetrahydro- lH-furo[3,4-d]pyrano[3,4-b]pyridin-8-yl)((4aS,6R,10bS)-6-methyl-8-(trifluoromethyl)- 2,3 ,4, 4a, 6, 1 Ob-hexahydro- lH-pyrano [3 ,2-b:5 ,4-b'] dipyridin- 1 -yl)methanone isomer 3 (Example 84) (5.0 mg, 12%) as a white solid with retention time at 15.343 minute.

[1849] The chiral resolution of rel-((3R,8S)-4-amino-3-methyl-3,6,8,9-tetrahydro-lH- furo[3,4-d]pyrano[3,4-b]pyridin-8-yl)((4aS,6R,10bS)-6-methyl-8-(trifluoromethyl)- 2,3,4,4a,6,10b-hexahydro-lH-pyrano[3,2-b:5,4-b']dipyridin-l-yl)methanone isomer 4 (Example 85) (8.6 mg, 22%) as a white solid with retention time at 23.63 minute. [1850] rel-((3R,8S)-4-amino-3-methyl-3,6,8,9-tetrahydro-lH-furo[3,4-d]pyrano[3,4- b]pyridin-8-yl)((4aS,6R,10bS)-6-methyl-8-(trifluoromethyl)-2,3,4,4a,6,10b-hexahydro-lH- pyrano[3,2-b:5,4-b']dipyridin-l-yl)methanone isomer 1 (Example 82): MS ESI calculated for C25H27F3N4O4 [M+H]⁺, 505.20; found, 505.20. 'H NMR (400 MHz, DMSO-d₆) 8 8.10 - 7.94 (m, 1H), 7.94 - 7.77 (m, 1H), 5.77 (s, 2H), 5.64 - 5.16 (m, 2H), 5.05 - 4.88 (m, 2H), 4.88 - 4.78 (m, 1H), 4.77 - 4.63 (m, 2H), 4.63 - 4.48 (m, 1H), 4.37 - 4.19 (m, 1H), 3.71 - 3.83 (m, 1H), 3.14 - 3.00 (m, 1H), 2.99 - 2.90 (m, 1H), 2.45 - 2.22 (m, 1H), 1.97 - 1.75 (m, 2H), 1.75 - 1.40 (m, 5H), 1.34 (d, J = 6.0 Hz, 3H).

[1851] rel-((3R,8S)-4-amino-3-methyl-3,6,8,9-tetrahydro-lH-furo[3,4-d]pyrano[3,4- b]pyridin-8-yl)((4aS,6R,10bS)-6-methyl-8-(trifluoromethyl)-2,3,4,4a,6,10b-hexahydro-lH- pyrano[3,2-b:5,4-b']dipyridin-l-yl)methanone isomer 2 (Example 83): MS ESI calculated for C25H27F3N4O4 [M+H]⁺, 505.20; found, 505.15. 'H NMR (400 MHz, DMSO-d₆) 8 8.04 - 7.84 (m, 2H), 5.77 (s, 2H), 5.64 - 5.54 (m, 1H), 5.20 - 5.28 (m, 1H), 4.98 - 4.86 (m, 3H), 4.74 - 4.65 (m, 2H), 4.59 - 4.50 (m, 1H), 4.35 - 4.20 (m, 1H), 3.83 - 3.72 (m, 1H), 3.22 - 2.88 (m, 2H), 2.48 - 2.43 (m, 1H), 1.77 - 1.48 (m, 7H), 1.39 - 1.31 (m, 3H).

[1852] rel-((3R,8S)-4-amino-3-methyl-3,6,8,9-tetrahydro-lH-furo[3,4-d]pyrano[3,4- b]pyridin-8-yl)((4aS,6R,10bS)-6-methyl-8-(trifluoromethyl)-2,3,4,4a,6,10b-hexahydro-lH- pyrano[3,2-b:5,4-b']dipyridin-l-yl)methanone isomer 3 (Example 84):MS ESI calculated for C25H27F3N4O4 [M+H]⁺, 505.20; found, 505.20. ’H NMR (400 MHz, DMSO-d₆) ’H NMR (400 MHz, DMSO-ifc) 8 7.96 - 7.84 (m, 2H), 5.77 (s, 2H), 5.65 - 5.47 (m, 1H), 5.30 - 5.19 (m, 1H), 5.08 - 4.80 (m, 3H), 4.80 - 4.62 (m, 2H), 4.60 - 4.48 (m, 1H), 4.40 - 4.17 (m, 1H), 3.89 - 3.76 (m, 1H), 3.18 - 3.05 (m, 1H), 3.04 - 2.92 (m, 1H), 2.45 - 2.30 (m, 1H), 1.93 - 1.71 (m, 2H), 1.70 - 1.40 (m, 5H), 1.38 - 1.25 (m, 3H).

[1853] rel-((3R,8S)-4-amino-3-methyl-3,6,8,9-tetrahydro-lH-furo[3,4-d]pyrano[3,4- b]pyridin-8-yl)((4aS,6R,10bS)-6-methyl-8-(trifluoromethyl)-2,3,4,4a,6,10b-hexahydro-lH- pyrano[3,2-b:5,4-b']dipyridin-l-yl)methanone isomer 4 (Example 85): MS ESI calculated for C25H27F3N4O4 [M+H]⁺, 505.20; found, 505.20. 'H NMR (400 MHz, DMSO-d₆) 'H NMR (400 MHz, DMSO- fc) 8 8.11 - 7.78 (m, 2H), 5.78 (s, 2H), 5.64 - 5.17 (m, 2H), 5.09 - 4.92 (m, 1H), 4.91 - 4.78 (m, 2H), 4.77 - 4.64 (m, 2H), 4.63 - 4.48 (m, 1H), 4.44 - 4.14 (m, 1H), 3.70 - 3.82 (m, 1H), 3.16 - 3.01 (m, 1H), 3.01 - 2.87 (m, 1H), 2.48 - 2.30 (m, 1H), 1.95 - 1.76 (m, 2H), 1.75 - 1.43 (m, 5H), 1.41 - 1.29 (m, 3H). Example 86: ((3R,8R)-4-amino-3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4- c][l,7]naphthyridin-8-yl)((4R*,4aR*,10bS*)-4-methoxy-8-(trifluoromethyl)-2,3,4,4a,6,10b- hexahydro- 1 H-pyrano [3 ,2-b :5 ,4-b'] dipyridin- 1 -yl)methanone

CA6 isomer 3

[1854] Followed the procedure of Example 38 with intermediate A98 isomer 2 (50 mg, 0.173 mmol) and intermediate CA6 isomer 3 (66 mg, 0.19 mmol) to afford ((3R,8R)-4- amino-3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4-c][l,7]naphthyridin-8-yl)((4R*,4aR*,10bS*)- 4-methoxy-8-(trifhioromethyl)-2,3 ,4, 4a, 6, 1 Ob-hexahydro- 1 H-pyrano [3 ,2-b : 5,4-b'] dipyridin- l-yl)methanone (Example 86) (1.8 mg, 7% yield) as a white solid. MS ESI calculated for C25H28F3N5O4 [M+H]⁺, 520.21; found, 520.30. ’H NMR (400 MHz, DMSO) 58.41 - 7.46 (m, 2H), 6.09 - 5.74 (m, 1H), 5.63 - 5.61 (m, 2H), 5.24 - 5.23 (m, 1H), 4.96 - 4.90 (m, 1H), 4.88 - 4.76 (m, 3H), 4.10 - 4.08 (m, 2H), 3.88 - 3.78 (m, 1H), 3.76 - 3.75 (m, 1H), 3.68 - 3.55 (m, 2H), 3.36 - 3.35 (m, 3H), 2.77 - 2.68 (m, 1H), 2.62 - 2.55 (m, 2H), 2.23 - 1.96 (m, 2H), 1.48 - 1.38 (m, 1H), 1.33 (d, J = 6.0 Hz, 3H).

Example 87: ((3R,8R)-4-amino-3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4- c][l,7]naphthyridin-8-yl)((4R*,4aR*,9bS*)-4-hydroxy-7-(trifluoromethyl)-3,4,4a,9b- tetrahydrofuro[2,3-b:4,5-b']dipyridin-l(2H)-yl)methanone

Example 48

[1855] To a stirred solution of Example 48 (5 mg, 0.01 mmol) in DCM (1 mL) were added Boron tribromide (1.0 M in DCM) (0.2 mL) at 0 °C under nitrogen atmosphere. The resulting mixture was stirred at 40 °C for 16 h. The reaction was quenched with water at 0 °C and concentrated under vacuum. The crude residue was purified by reversed-phase flash column chromatography with 10% to 50% MeCN in Water (10 mmol/L NH4HCO3), gradient in 40 min; detector, UV 254 nm] to afford ((3R,8R)-4-amino-3-methyl-l,3,6,7,8,9- hexahydrofuro[3,4-c][l,7]naphthyridin-8-yl)((4R*,4aR*,9bS*)-4-hydroxy-7- (trifhioromethyl)-3,4,4a,9b-tetrahydrofuro[2,3-b:4,5-b']dipyridin-l(2H)-yl)methanone (Example 87) (0.9 mg, 18%) as a white solid. MS ESI calculated for C23H24F3N5O4 [M+H]⁺, 492.18; found. 492.20.

Example 88: ((3R,8R)-4-amino-3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4- c][l,7]naphthyridin-8-yl)((3R,4aS,9bS)-3-methyl-7-(trifluoromethyl)-3,4,4a,9b- tetrahydrofuro[2,3-b:4,5-b']dipyridin-l(2H)-yl)methanone

A106 isomer 1

[1856] Followed the procedure of Example 39 with intermediate A106 isomer 1 (30 mg, 0.12 mmol) and intermediate CA6 isomer 3 (41 mg, 0.12 mmol) to afford ((3R,8R)-4-amino- 3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4-c][l,7]naphthyridin-8-yl)((3R,4aS,9bS)-3-methyl-7- (trifhioromethyl)-3,4,4a,9b-tetrahydrofuro[2,3-b:4,5-b']dipyridin-l(2H)-yl)methanone (Example 88) (19.3 mg, 46%) as a white solid. MS ESI calculated for (C24H26F3N5O3) [M+H]⁺, 490.20; found 490.15. *H NMR (400 MHz, DMSO) 5 8.17 - 7.62 (m, 1H), 7.60 - 7.38 (m, 1H), 6.25 - 6.07 (m, 1H), 5.62 (d, J = 3.6 Hz, 2H), 5.23 (d, J = 6.4 Hz, 1H), 5.17 - 5.09 (m, 1H), 5.01 - 4.91 (m, 1H), 4.84 - 4.72 (m, 1H), 4.44 - 3.97 (m, 2H), 3.83 - 3.64 (m, 2H), 2.83 - 2.58 (m, 2H), 2.43 (s, 1H), 2.33 (d, J = 4.8 Hz, 1H), 2.20 - 1.92 (m, 1H), 1.89 - 1.57 (m, 1H), 1.36 - 1.29 (m, 3H), 1.28 - 1.21 (m, 1H), 0.93 - 0.85 (m, 3H).

Example 89: ((3R,8R)-4-amino-3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4- c][l,7]naphthyridin-8-yl)((3S,4aS,9bS)-3-methyl-7-(trifluoromethyl)-3,4,4a,9b- tetrahydrofuro[2,3-b:4,5-b']dipyridin-l(2H)-yl)methanone

Followed the procedure of Example 39 with intermediate A 106 isomer 2 (30 mg, 0.12 mmol) and intermediate CA6 isomer 3 (44 mg, 0.17 mmol) to afford ((3R,8R)-4-amino-3- methyl-l,3,6,7,8,9-hexahydrofuro[3,4-c][l,7]naphthyridin-8-yl)((3S,4aS,9bS)-3-methyl-7- (trifhioromethyl)-3,4,4a,9b-tetrahydrofuro[2,3-b:4,5-b']dipyridin-l(2H)-yl)methanone (Example 89) (20.4 mg, 43%) as a white solid. MS ESI calculated for C24H26F3N5O3 [M+H]⁺, 490.20; found 490.15. 'H NMR (400 MHz, DMSO) 5 8.20 - 7.68 (m, 1H), 7.54 - 7.37 (m, 1H), 6.26 (d, J= 9.6 Hz, 1H), 5.74 - 5.57 (m, 2H), 5.41 - 5.12 (m, 2H), 5.04 - 4.88 (m, 1H), 4.88 - 4.70 (m, 1H), 4.10 (d, J = 9.2 Hz, 1H), 3.95 - 3.67 (m, 2H), 3.62 - 3.48 (m, 1H), 3.33 - 3.23 (m, 1H), 2.88 - 2.77 (m, 1H), 2.76 - 2.57 (m, 1H), 2.48 - 2.25 (m, 1H), 2.09 - 1.90 (m, 1H), 1.74 (d, J = 11.2 Hz, 1H), 1.63 - 1.41 (m, 1H), 1.36 - 1.28 (m, 3H), 1.02 - 0.87 (m, 3H).

Example 90: ((3R,8R)-4-amino-3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4- c] [ 1 ,7]naphthyridin-8-yl)((4aS,6R, 10bS)-8-(difluoromethoxy)-6-methyl-2,3,4,4a,6, 10b- hexahydro- 1 H-pyrano [3 ,2-b : 5 ,4-b '] dipyridin- 1 -yl)methanone

[1857] Followed the procedure of Example 39 with intermediate A107 (40 mg, 0.13 mmol) and intermediate CA6 isomer 3 (59 mg, 0.17 mmol) to afford ((3R,8R)-4-amino-3-methyl- l,3,6,7,8,9-hexahydrofuro[3,4-c][l,7]naphthyridin-8-yl)((4aS,6R,10bS)-8-(difluoromethoxy)- 6-methyl-2,3,4,4a,6,10b-hexahydro-lH-pyrano[3,2-b:5,4-b']dipyridin-l-yl)methanone (Example 90) (31.7 mg, 77% yield) as a white solid. MS ESI calculated for C25H29F2N5O4 [M+H]⁺, 502.22; found, 502.25. 'H NMR (400 MHz, DMSO) 8 7.96 - 7.49 (m, 2H), 7.02 (d, J = 8.4 Hz, 1H), 5.61 (s, 2H), 5.44 (d, J = 5.6 Hz, 1H), 5.22 (d, J= 6.0 Hz, 1H), 4.93 (dd, 7 = 13.6, 3.2 Hz, 1H), 4.84 - 4.58 (m, 2H), 4.17 - 4.16 (m, 1H), 3.97 - 3.96 (m, 1H), 3.87 - 3.50 (m, 3H), 3.07 - 3.06 (m, 1H), 2.80 - 2.59 (m, 1H), 2.47 - 2.23 (m, 1H), 2.04 - 1.80 (m, 2H), 1.74 - 1.40 (m, 6H), 1.31 (d, J = 6.0 Hz, 3H).

Example 91: ((3R,8R)-4-amino-3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4- c][l,7]naphthyridin-8-yl)((3R,4aR*,10bR*)-8-(difluoromethoxy)-3-methoxy-2,3,4,4a,6,10b- hexahydro- 1 H-pyrano [3 ,2-b :5 ,4-b'] dipyridin- 1 -yl)methanone

[1858] Followed the procedure of Example 39 with intermediate A108 (50 mg, 0.17 mmol) and intermediate CA6 isomer 3 (79 mg, 0.23 mmol) to afford ((3R,8R)-4-amino-3-methyl- l,3,6,7,8,9-hexahydrofuro[3,4-c][l,7]naphthyridin-8-yl)((3R,4aR*,10bR*)-8- (difluoromethoxy)-3-methoxy-2,3,4,4a,6,10b-hexahydro-lH-pyrano[3,2-b:5,4-b']dipyridin-l- yl)methanone (Example 91) (22.0 mg, 54%) as an orange solid. MS ESI calculated for C25H29F2N5O5 [M+H]⁺, 518.21; found, 518.30. 'H NMR (400 MHz, DMSO) 87.96 - 7.35 (m, 2H), 7.11 - 6.98 (m, 1H), 5.86 - 5.59 (m, 3H), 5.24 - 5.23 (m, 1H), 5.02 - 4.88 (m, 1H), 4.87 - 4.73 (m, 1H), 4.77 - 4.50 (m, 2H), 4.37 - 4.18 (m, 1H), 4.17 - 3.97 (m, 2H), 3.88 - 3.58 (m, 2H), 3.50 - 3.49 (m, 1H), 3.30 - 3.25 (m, 2H), 2.88 - 2.75 (m, 1H), 2.32 (d, J= 12.4 Hz, 1H), 2.27 - 2.09 (m, 2H), 1.88 - 1.45 (m, 2H), 1.33 - 1.31 (m, 3H).

Example 92: (4aS,6R,10bS)-l-((3R,8R)-4-amino-3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4- c][l,7]naphthyridine-8-carbonyl)-6-methyl-2,3,4,4a,6,10b-hexahydro-lH-pyrano[3,2-b:5,4- b']dipyridine-8-carbonitrile

A109

[1859] Followed the procedure of Example 38 with intermediate A109 (40 mg, 0.17 mmol) and intermediate CA6 isomer 3 (67 mg, 0.19 mmol) to afford (4aS,6R,10bS)-l-((3R,8R)-4- amino-3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4-c][l,7]naphthyridine-8-carbonyl)-6-methyl- 2,3 ,4, 4a, 6, 1 Ob-hexahydro- lH-pyrano [3 ,2-b:5 ,4-b'] dipyridine-8-carbonitrile (Example 92) (17.8 mg, 83% yield) as a white solid. MS ESI calculated for C25H28N6O3 [M+H]⁺, 461.22; found, 461.20. 'H NMR (400 MHz, DMSO) 8 8.01 - 7.86 (m, 2H), 5.63 - 5.61 (m, 3H), 5.23 (d, J = 6.8 Hz, 1H), 4.96 - 4.72 (m, 3H), 4.22 - 4.21 (m, 1H), 4.07 - 3.61 (m, 4H), 2.99 - 2.87 (m, 1H), 2.70 - 2.60 (m, 1H), 2.52 - 2.51 (m, 1H), 2.48 - 2.28 (m, 1H), 1.87 - 1.86 (m, 1H), 1.79 - 1.70 (m, 1H), 1.58 - 1.56 (m, 5H), 1.32 (d, J= 6.2 Hz, 3H).

Example 93: rel-((3R,8S)-4-amino-3-methyl-3,6,8,9-tetrahydro- lH-furo[3,4- d]pyrano[3,4-b]pyridin-8-yl)((4aS,9bS)-7-(difluoromethoxy)-3,4,4a,9b- tetrahydrofuro[2,3-b:4,5-b']dipyridin-l(2H)-yl)methanone, isomer 1 isomer 1 .

Example 94: rel-((3R,8S)-4-amino-3-methyl-3,6,8,9-tetrahydro- lH-furo[3,4- d]pyrano[3,4-b]pyridin-8-yl)((4aS,9bS)-7-(difluoromethoxy)-3,4,4a,9b- tetrahydrofuro[2,3-b:4,5-b']dipyridin-l(2H)-yl)methanone, isomer 2

isomer 2 _{; and}

Example 95: rel-((3R,8S)-4-amino-3-methyl-3,6,8,9-tetrahydro- lH-furo[3,4- d]pyrano[3,4-b]pyridin-8-yl)((4aS,9bS)-7-(difluoromethoxy)-3,4,4a,9b- tetrahydrofuro[2,3-b:4,5-b']dipyridin-l(2H)-yl)methanone, isomer 1

Example 96: rel-((3R,8S)-4-amino-3-methyl-3,6,8,9-tetrahydro- lH-furo[3,4- d]pyrano[3,4-b]pyridin-8-yl)((4aS,9bS)-7-(difluoromethoxy)-3,4,4a,9b- tetrahydrofuro[2,3-b:4,5-b']dipyridin-l(2H)-yl)methanone, isomer 4

Example 97 : rel-((3R,8S)-4-amino-3-methyl-3,6,8,9-tetrahydro- lH-furo[3,4- d]pyrano[3,4-b]pyridin-8-yl)((4aS,9bS)-7-(difluoromethoxy)-3,4,4a,9b- tetrahydrofuro[2,3-b:4,5-b']dipyridin-l(2H)-yl)methanone, isomer 5

isomer 5 _{; and}

Example 98: rel-((3R,8S)-4-amino-3-methyl-3,6,8,9-tetrahydro- lH-furo[3,4- d]pyrano[3,4-b]pyridin-8-yl)((4aS,9bS)-7-(difluoromethoxy)-3,4,4a,9b- tetrahydrofuro[2,3-b:4,5-b']dipyridin-l(2H)-yl)methanone, isomer 6

Example 99: rel-((3R,8S)-4-amino-3-methyl-3,6,8,9-tetrahydro- lH-furo[3,4- d]pyrano[3,4-b]pyridin-8-yl)((4aS,9bS)-7-(difluoromethoxy)-3,4,4a,9b- tetrahydrofuro[2,3-b:4,5-b']dipyridin-l(2H)-yl)methanone, isomer 7

Example 100: rel-((3R,8S)-4-amino-3-methyl-3,6,8,9-tetrahydro-lH-furo[3,4- d]pyrano[3,4-b]pyridin-8-yl)((4aS,9bS)-7-(difluoromethoxy)-3,4,4a,9b- tetrahydrofuro[2,3-b:4,5-b']dipyridin-l(2H)-yl)methanone, isomer 8

Step-1:

[1860] To a stirred solution of intermediate A71 (57 mg, 0.20 mmol) and DIEA (66 mg, 0.51 mmol) in DMAc (3 mL) were added intermediate CA12 (80 mg, 0.17 mmol) and CMPI (65 mg, 0.26 mmol). The resulting mixture was stirred at room temperature for 1 h under nitrogen atmosphere. The resulting mixture was quenched with water and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous Na2SC>4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0 ~ 62% EtOAc in petroleum ether to afford rac-tert-butyl ((3R,8S)-8-((4aS,9bS)-7-(difluoromethoxy)-l,2,3,4,4a,9b- hexahydrofuro[2,3-b:4,5-b']dipyridine-l-carbonyl)-3-methyl-3,6,8,9-tetrahydro-lH-furo[3,4- d]pyrano[3,4-b]pyridin-4-yl)(4-methoxybenzyl)carbamate (110 mg, 93%) as a colorless oil, which is a mixture contained 8 diastereomers. MS ESI calculated for C36H40F2N4O8 [M+H]⁺, 695.28; found, 695.35.

[1861] A solution of rac-tert-butyl ((3R,8S)-8-((4aS,9bS)-7-(difluoromethoxy)- l,2,3,4,4a,9b-hexahydrofuro[2,3-b:4,5-b']dipyridine-l-carbonyl)-3-methyl-3,6,8,9-tetrahydro- lH-furo[3,4-d]pyrano[3,4-b]pyridin-4-yl)(4-methoxybenzyl)carbamate (100 mg, 0.14 mmol) in TFA (5 mL) was stirred at 50 °C for 1 h under nitrogen atmosphere. The mixture was allowed to cool down to room temperature and concentrated under vacuum. The residue was purified by reverse phase column chromatography with the following conditions: [ column, C18 silica gel; mobile phase, MeCN in Water (0.1% TFA), 5% to 41% gradient in 20 min; detector, UV 254 nm] to afford rac-((3R,8S)-4-amino-3-methyl-3,6,8,9-tetrahydro-lH- furo[3,4-d]pyrano[3,4-b]pyridin-8-yl)((4aS,9bS)-7-(difluoromethoxy)-3,4,4a,9b- tetrahydrofuro[2,3-b:4,5-b']dipyridin-l(2H)-yl)methanone (60 mg, 87%) as a colorless oil, which is a mixture of 8 diastereomers.

[1862] This mixture (60 mg) was separated by Perp-Chiral-HPLC with the following conditions: [Column: CHIRALPAK IB, 2*25 cm, 5 pm; Mobile Phase A: Hex (0.5% 2M NH₃-MeOH)— HPLC, Mobile Phase B: MeOH: DCM=1 : 1-HPLC; Flow rate: 20 mL/min; Gradient (B%): isocratic 25% B to 25% in 23min% B; Wave Length: 220/254 nm; RTl(min): 11.843; RT2(min): 13.158; RT3(min): 14.697; RT4(min): 18.18; RT5(min): 19.105; RT6(min): 21.054; Sample Solvent: MeOH: DCM=1: 1-HPLC; Injection Volume: 0.4 mL; Number Of Runs: 7] to afford fraction A (2 mg), fraction B (13 mg), fraction C (7 mg), fraction D (3 mg), fraction E (1.4 mg) and fraction F (4 mg).

[1863] The fraction A was rel-((3R,8S)-4-amino-3-methyl-3,6,8,9-tetrahydro- lH-furo[3,4- d]pyrano[3,4-b]pyridin-8-yl)((4aS,9bS)-7-(difhioromethoxy)-3,4,4a,9b-tetrahydrofuro[2,3- b:4,5-b']dipyridin-l(2H)-yl)methanone, isomer 1 (Example 93) (2.0 mg, 3%) as a white solid with retention time at 11.843 min on prep Chiral HPLC. MS ESI calculated for C23H24F2N4O5 [M+H]⁺, 475.17; found, 475.20. 'H NMR (400 MHz, DMSO-d₆) 3 8.11 (d, J = 8.4 Hz, 1H), 7.96 (t, J = 6.0 Hz, 1H), 7.67 (t, J = 72.8 Hz, 1H), 6.99 (d, J = 8.0 Hz, 1H), 6.72 (s, 1H), 5.75 (s, 2H), 5.28 - 5.17 (m, 1H), 4.94 - 4.80 (m, 2H), 4.69 - 4.47 (m, 2H), 4.17 - 4.08 (m, 1H), 3.22 (q, J = 6.4 Hz, 2H), 2.79 (t, J = 7.2 Hz, 2H), 2.74 - 2.54 (m, 2H), 1.93 - 1.79 (m, 2H), 1.33 (d, 7 = 6.0 Hz, 3H).

[1864] The fraction B with retention time at 13.158 min was further separated by Perp- Chiral-HPLC with the following conditions: [Column: CHIRAL ART Cellulose-SC, 2*25 cm, 5 pm; Mobile Phase A: Hex(0.5% 2M NH₃-MeOH)— HPLC, Mobile Phase B: MeOH: DCM=1: 1— HPLC; Flow rate: 20 mL/min; Gradient (B%): isocratic 25% B to 25% in 21min% B; Wave Length: 220/254 nm; RTl(min): 15.79; RT2(min): 17.34; Sample Solvent: MeOH: DCM=1: 1-HPLC; Injection Volume: 0.4 mL; Number Of Runs: 3] to afford rel- ((3R,8S)-4-amino-3-methyl-3,6,8,9-tetrahydro-lH-furo[3,4-d]pyrano[3,4-b]pyridin-8- yl)((4aS,9bS)-7-(difluoromethoxy)-3,4,4a,9b-tetrahydrofuro[2,3-b:4,5-b']dipyridin-l(2H)- yl)methanone, isomer 2 (Example 94) (4.0 mg, 7%) as a white solid with retention time at 15.79 min on Perp-Chiral-HPLC and rel-((3R,8S)-4-amino-3-methyl-3,6,8,9-tetrahydro-lH- furo[3,4-d]pyrano[3,4-b]pyridin-8-yl)((4aS,9bS)-7-(difluoromethoxy)-3,4,4a,9b- tetrahydrofuro[2,3-b:4,5-b']dipyridin-l(2H)-yl)methanone, isomer 3 (Example 95) (2.5 mg, 4%) as a white solid with retention time at 17.34 min on Perp-Chiral-HPLC.

[1865] rel-((3R,8S)-4-amino-3-methyl-3,6,8,9-tetrahydro-lH-furo[3,4-d]pyrano[3,4- b]pyridin-8-yl)((4aS,9bS)-7-(difluoromethoxy)-3,4,4a,9b-tetrahydrofuro[2,3-b:4,5- b']dipyridin-l(2H)-yl)methanone, isomer 2 (Example 94): MS ESI calculated for C23H24F2N4O5 [M+H]⁺, 475.17; found, 475.15. ’H NMR (400 MHz, DMSO-d₆) 87.90 - 7.38 (m, 2H), 6.65 - 6.55 (m, 1H), 6.09 - 5.64 (m, 3H), 5.32 - 5.10 (m, 2H), 5.06 - 4.47 (m, 5H), 4.17 - 3.77 (m, 1H), 3.04 - 2.78 (m, 2H), 2.47 - 2.31 (m, 1H), 2.06 - 1.45 (m, 4H), 1.36 - 1.28 (m, 3H).

[1866] rel-((3R,8S)-4-amino-3-methyl-3,6,8,9-tetrahydro-lH-furo[3,4-d]pyrano[3,4- b]pyridin-8-yl)((4aS,9bS)-7-(difluoromethoxy)-3,4,4a,9b-tetrahydrofuro[2,3-b:4,5- b']dipyridin-l(2H)-yl)methanone, isomer 3 (Example 95): MS ESI calculated for C23H24F2N4O5 [M+H]⁺, 475.17; found, 475.20. ¹H NMR (400 MHz, DMSO-d₆) 87.95 - 7.41 (m, 2H), 6.64 - 6.53 (m, 1H), 6.10 - 5.94 (m, 1H), 5.83 - 5.71 (m, 2H), 5.29 - 5.11 (m, 2H), 5.02 - 4.43 (m, 5H), 4.15 - 3.75 (m, 1H), 3.04 - 2.85 (m, 2H), 2.47 - 2.30 (m, 1H), 2.01 - 1.44 (m, 4H), 1.34 (d, J = 6.0 Hz, 3H).

[1867] The fraction C with retention time at 14.697 min was further separated by Perp- Chiral-HPLC with the following conditions: [Column: CHIRAL ART Cellulose-SC, 2*25 cm, 5 pm; Mobile Phase A: Hex (0.5% 2M NH₃-MeOH)-HPLC, Mobile Phase B: MeOH: DCM=1: 1— HPLC; Flow rate: 20 mL/min; Gradient (B%): isocratic 25% B to 25% in 22min% B; Wave Length: 220/254 nm; RTl(min): 15.94; RT2(min): 17.83; Sample Solvent: MeOH: DCM=1: 1-HPLC; Injection Volume: 0.8 mL; Number Of Runs: 1] to afford rel- ((3R,8S)-4-amino-3-methyl-3,6,8,9-tetrahydro-lH-furo[3,4-d]pyrano[3,4-b]pyridin-8- yl)((4aS,9bS)-7-(difluoromethoxy)-3,4,4a,9b-tetrahydrofuro[2,3-b:4,5-b']dipyridin-l(2H)- yl)methanone, isomer 4 (Example 96) (1.8 mg, 3%) as a white solid with retention time at 15.94 min on Perp-Chiral-HPLC and rel-((3R,8S)-4-amino-3-methyl-3,6,8,9-tetrahydro-lH- furo[3,4-d]pyrano[3,4-b]pyridin-8-yl)((4aS,9bS)-7-(difluoromethoxy)-3,4,4a,9b- tetrahydrofuro[2,3-b:4,5-b']dipyridin-l(2H)-yl)methanone, isomer 5 (Example 97) (1.8 mg, 3%) as a white solid with retention time at 17.83 min on Perp-Chiral-HPLC.

[1868] rel-((3R,8S)-4-amino-3-methyl-3,6,8,9-tetrahydro-lH-furo[3,4-d]pyrano[3,4- b]pyridin-8-yl)((4aS,9bS)-7-(difluoromethoxy)-3,4,4a,9b-tetrahydrofuro[2,3-b:4,5- b']dipyridin-l(2H)-yl)methanone, isomer 4 (Example 96): MS ESI calculated for C23H24F2N4O5 [M+H]⁺, 475.17; found, 475.20. ’H NMR (400 MHz, DMSO-7₆) 87.88 - 7.39 (m, 2H), 6.66 - 6.55 (m, 1H), 6.07 - 5.66 (m, 3H), 5.30 - 5.08 (m, 2H), 5.02 - 4.46 (m, 5H), 4.17 - 3.76 (m, 1H), 3.01 - 2.82 (m, 2H), 2.47 - 2.28 (m, 1H), 2.05 - 1.45 (m, 4H), 1.41 -

1.27 (m, 3H).

[1869] rel-((3R,8S)-4-amino-3-methyl-3,6,8,9-tetrahydro-lH-furo[3,4-d]pyrano[3,4- b]pyridin-8-yl)((4aS,9bS)-7-(difluoromethoxy)-3,4,4a,9b-tetrahydrofuro[2,3-b:4,5- b']dipyridin-l(2H)-yl)methanone, isomer 5 (Example 97): MS ESI calculated for C23H24F2N4O5 [M+H]⁺, 475.17; found, 475.20. ¹H NMR (400 MHz, DMSO-d₆) 88.11 (d, J = 8.4 Hz, 1H), 7.97 (t, J = 6.0 Hz, 1H), 7.67 (t, J = 72.8 Hz, 1H), 6.99 (d, J = 8.0 Hz, 1H), 6.72 (s, 1H), 5.75 (s, 2H), 5.30 - 5.14 (m, 1H), 5.05 - 4.71 (m, 2H), 4.59 (s, 2H), 4.20 - 4.11 (m, 1H), 3.26 - 3.16 (m, 2H), 2.79 (t, J = 7.2 Hz, 2H), 2.74 - 2.54 (m, 2H), 1.93 - 1.80 (m, 2H), 1.33 (d, J = 6.0 Hz, 3H).

[1870] The fraction D with retention time at 18.18 min on prep Chiral HPLC was rel- ((3R,8S)-4-amino-3-methyl-3,6,8,9-tetrahydro-lH-furo[3,4-d]pyrano[3,4-b]pyridin-8- yl)((4aS,9bS)-7-(difhioromethoxy)-3,4,4a,9b-tetrahydrofuro[2,3-b:4,5-b']dipyridin-l(2H)- yl)methanone, isomer 6 (Example 98) (3 mg, 4%) as a white solid. MS ESI calculated for C23H24F2N4O5 [M+H]⁺, 475.17; found, 475.20. 'H NMR (400 MHz, DMSO-d₆) 87.93 - 7.38 (m, 2H), 6.65 - 6.56 (m, 1H), 6.12 - 5.96 (m, 1H), 5.79 - 5.68 (m, 2H), 5.31 - 5.12 (m, 2H), 5.03 - 4.42 (m, 5H), 4.18 - 3.76 (m, 1H), 3.06 - 2.86 (m, 2H), 2.47 - 2.37 (m, 1H), 2.03 - 1.46 (m, 4H), 1.34 (d, J = 6.0 Hz, 3H).

[1871] The fraction E with retention time at 19.105 min on prep-Chiral HPLC was rel- ((3R,8S)-4-amino-3-methyl-3,6,8,9-tetrahydro-lH-furo[3,4-d]pyrano[3,4-b]pyridin-8- yl)((4aS,9bS)-7-(difluoromethoxy)-3,4,4a,9b-tetrahydrofuro[2,3-b:4,5-b']dipyridin-l(2H)- yl)methanone, isomer 7 (Example 99) (1.4 mg, 2%). MS ESI calculated for C23H24F2N4O5 [M+H]⁺, 475.17; found, 475.20. 'H NMR (400 MHz, DMSO-7₆) 88.11 (d, J = 8.4 Hz, 1H), 7.96 (t, 7= 6.0 Hz, 1H), 7.67 (t, J= 72.8 Hz, 1H), 6.99 (d, J = 8.0 Hz, 1H), 6.72 (s, 1H), 5.74 (s, 2H), 5.30 - 5.15 (m, 1H), 4.93 - 4.81 (m, 2H), 4.66 - 4.48 (m, 2H), 4.17 - 4.07 (m, 1H),

3.27 - 3.17 (m, 2H), 2.79 (t, J = 7.2 Hz, 2H), 2.73 - 2.53 (m, 2H), 1.92 - 1.79 (m, 2H), 1.33 (d, 7 = 6.4 Hz, 3H).

[1872] The fraction F with retention time at 21.054 min on prep Chiral HPLC was rel- ((3R,8S)-4-amino-3-methyl-3,6,8,9-tetrahydro-lH-furo[3,4-d]pyrano[3,4-b]pyridin-8- yl)((4aS,9bS)-7-(difluoromethoxy)-3,4,4a,9b-tetrahydrofuro[2,3-b:4,5-b']dipyridin-l(2H)- yl)methanone, isomer 8 (Example 100) (4 mg, 7%). MS ESI calculated for C23H24F2N4O5 [M+H]⁺, 475.17; found, 475.20. 'H NMR (400 MHz, DMSO-d₆) 3 8.11 (d, J = 8.4 Hz, 1H), 7.97 (t, J = 6.0 Hz, 1H), 7.67 (t, J = 72.8 Hz, 1H), 6.99 (d, J = 8.0 Hz, 1H), 6.72 (s, 1H), 5.74 (s, 2H), 5.30 - 5.15 (m, 1H), 5.03 - 4.72 (m, 2H), 4.59 (s, 2H), 4.20 - 4.11 (m, 1H), 3.26 - 3.16 (m, 2H), 2.79 (t, J = 7.2 Hz, 2H), 2.73 - 2.53 (m, 2H), 1.93 - 1.80 (m, 2H), 1.33 (d, J = 6.0 Hz, 3H).

Example 101: ((3R,8R)-4-amino-3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4- c][l,7]naphthyridin-8-yl)((4R*,4aR*,9bR*)-4-methyl-7-(trifluoromethyl)-3,4,4a,9b- tetrahydrofuro[2,3-b:4,5-b']dipyridin-l(2H)-yl)methanone, isomer 1

Example 103: ((3R,8R)-4-amino-3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4- c][l,7]naphthyridin-8-yl)((4R*,4aR*,9bR*)-4-methyl-7-(trifluoromethyl)-3,4,4a,9b- tetrahydrofuro[2,3-b:4,5-b']dipyridin-l(2H)-yl)methanone, isomer 3

[1873] To a stirred solution of intermediate A68, isomer 1 (60 mg, 0.23 mmol) and intermediate CA6, isomer 3 (97 mg, 0.28 mmol) in DMF (2 mL) were added HATU (131 mg, 0.35 mmol) and DIEA (89 mg, 0.69 mmol). The resulting mixture was stirred at room temperature for 2 h. The resulting mixture was quenched with water and extracted with EtOAc. The combined organic layers were washed with water, dried over anhydrous Na2SC>4. After filtration, the filtrate was concentrated under reduced pressure.The resulting residue was purified by normal phase flash chromatography which applied to 25 g silica gel column and eluted with 0-100% ethyl acetate in petroleum ether within 30 min to afford tert-butyl (3R,8R)-4-amino-3-methyl-8-((4R*,4aR*,9bR*)-4-methyl-7-(trifluoromethyl)-l,2,3,4,4a,9b- hexahydrofuro[2,3-b:4,5-b']dipyridine-l-carbonyl)-3,6,8,9-tetrahydrofuro[3,4- c][l,7]naphthyridine-7(lH)-carboxylate (108 mg, 79%, d.e. 60%) as a yellow oil.

[1874] This product of tert-butyl (3R,8R)-4-amino-3-methyl-8-((4R*,4aR*,9bR*)-4- methyl-7-(trifluoromethyl)- 1 ,2,3,4,4a,9b-hexahydrofuro[2,3-b:4,5-b']dipyridine- 1-carbonyl)- 3,6,8,9-tetrahydrofuro[3,4-c][l,7]naphthyridine-7(lH)-carboxylate (108 mg, 79%, d.e. 60%) was dissolved in HC1 in 1,4-dioxane (4.0 M) (1 mL) and the mixture was stirred at room temperature for 1 h. The resulting mixture was concentrated under vacuum. The crude product was purified by Prep-HPLC with the following conditions: (Column: XBridge Prep OBD C18 Column30*150 mm; Mobile Phase A: Water (10 mmol/L NH4HCO3), Mobile Phase B: ACN; Flow rate: 60 mL/min; Gradient (B%): 5% B to 5% B in 2 min, 27% B to 47% B in 10 min; Wave Length: 254/220 nm; RTl(min): 9.5) to afford ((3R,8R)-4-amino-3- methyl-l,3,6,7,8,9-hexahydrofuro[3,4-c][l,7]naphthyridin-8-yl)((4R*,4aR*,9bR*)-4-methyl- 7-(trifhioromethyl)-3,4,4a,9b-tetrahydrofuro[2,3-b:4,5-b']dipyridin-l(2H)-yl)methanone (22 mg, 24%) as a white solid, which is a mixture containing a 20% diastereomer. This mixture (22 mg) was separated with the following conditions: [Column: CHIRALPAK IH, 2*25 cm, 5 pm; Mobile Phase A: Hex(0.5% 2M NH3-MeOH)-HPLC, Mobile Phase B: MeOH: ETOH=1: 1— HPLC; Flow rate: 20 mL/min; Gradient (B%): isocratic 15% B to 15% in 32min% B; Wave Length: 220/254 nm; RTl(min): 18.92; RT2(min): 22.87; Sample Solvent: MeOH: DCM=1: 1-HPLC; Injection Volume: 0.5 mL; Number Of Runs: 2] to afford ((3R,8R)-4-amino-3-methyl-l ,3,6,7,8,9-hexahydrofuro[3,4-c] [1 ,7]naphthyridin-8- yl)((4R*,4aR*,9bR*)-4-methyl-7-(trifluoromethyl)-3,4,4a,9b-tetrahydrofuro[2,3-b:4,5- b']dipyridin-l(2H)-yl)methanone, isomer 1 (Example 101) (11.7 mg) as a white solid with retention time at 22.87 min on prep-Chiral HPLC and ((3R,8R)-4-amino-3-methyl- l,3,6,7,8,9-hexahydrofuro[3,4-c][l,7]naphthyridin-8-yl)((4R*,4aR*,9bR*)-4-methyl-7- (trifluoromethyl)-3,4,4a,9b-tetrahydrofuro[2,3-b:4,5-b^,]dipyridin-l(2H)-yl)methanone, isomer 3 (Example 103) (1.4 mg) as a white solid with the rentention time at 18.92 min on prep-Chiral HPLC.

[1875] ((3R,8R)-4-amino-3-methyl-l ,3,6,7,8,9-hexahydrofuro[3,4-c] [1 ,7]naphthyridin-8- yl)((4R*,4aR*,9bR*)-4-methyl-7-(trifluoromethyl)-3,4,4a,9b-tetrahydrofuro[2,3-b:4,5- b']dipyridin-l(2H)-yl)methanone, isomer 1 (Example 101): MS (ESI) calc’ d for C24H26F3N5O3 [M+H]⁺, 490.20; found, 490.10. 'H NMR (400 MHz, DMSO-d₆) 88.17 and 7.83 (d, J = 7.2 Hz, 1H), 7.52 - 7.43 (m, 1H), 6.23 - 6.20 (m, IH), 5.75 - 5.73 (m, 2H), 5.22 (br, IH), 5.13 - 4.78 (m, 3H), 4.23 - 3.75 (m, 5H), 2.92 - 2.67 (m, 3H), 2.35 - 2.28 (m, IH), 1.98 - 1.72 (m, 2 H), 1.42 - 1.35 (m, 3H), 1.16 - 1.08 (m, 3H).

[1876] ((3R,8R)-4-amino-3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4-c][l,7]naphthyridin-8- yl)((4R*,4aR*,9bR*)-4-methyl-7-(trifluoromethyl)-3,4,4a,9b-tetrahydrofuro[2,3-b:4,5- b']dipyridin-l(2H)-yl)methanone, isomer 3 (Example 103): MS (ESI) calc’ d for C24H26F3N5O3 [M+H]⁺, 490.20; found, 490.20. ’H NMR (400 MHz, DMSO-d₆) 88.07 and 7.83 (d, 7 = 7.2 Hz, 1H), 7.45 (d, 7 = 7.2 Hz, 1H), 6.38 - 6.19 (m, 1H), 5.73 (br, 2H), 5.32 (br, 1H), 5.18 - 4.78 (m, 3H), 4.17 - 3.72 (m, 5H), 2.92 - 2.67 (m, 3H), 2.35 - 2.32 (m, 1H), 1.98 - 1.82 (m, 2 H), 1.34 - 1.30 (m, 3H), 1.16 - 1.12 (m, 3H).

Example 102: ((3R,8R)-4-amino-3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4- c][l,7]naphthyridin-8-yl)((4R*,4aR*,9bR*)-4-methyl-7-(trifluoromethyl)-3,4,4a,9b- tetrahydrofuro[2,3-b:4,5-b']dipyridin-l(2H)-yl)methanone, isomer 2

[1877] To a stirred solution of intermediate A68, isomer 2 (30 mg, 0.12 mmol) and intermediate CA6, isomer 3 (49 mg, 0.14 mmol) in DMF (1 mL) were added HATU (68 mg, 0.18 mmol) and DIEA (46 mg, 0.36 mmol). The resulting mixture was stirred at room temperature for 2 h. The resulting mixture was quenched with water and extracted with EtOAc. The combined organic layers were washed with water, dried over anhydrous Na2SC>4. After filtration, the filtrate was concentrated under reduced pressure.The resulting residue was purified by normal phase flash chromatography which applied to 25 g silica gel column and eluted with 0-100% ethyl acetate in petroleum ether within 30 min to afford tert-butyl (3R,8R)-4-amino-3-methyl-8-((4R*,4aR*,9bR*)-4-methyl-7-(trifluoromethyl)-l,2,3,4,4a,9b- hexahydrofuro[2,3-b:4,5-b']dipyridine-l-carbonyl)-3,6,8,9-tetrahydrofuro[3,4- c][l,7]naphthyridine-7(lH)-carboxylate (45 mg, 63%) as a yellow oil.

[1878] This product of tert-butyl (3R,8R)-4-amino-3-methyl-8-((4R*,4aR*,9bR*)-4- methyl-7-(trifluoromethyl)- 1 ,2,3,4,4a,9b-hexahydrofuro[2,3-b:4,5-b']dipyridine- 1-carbonyl)- 3.6.8.9-tetrahydrofuro[3,4-c][l,7]naphthyridine-7(lH)-carboxylate (45 mg, 0.08 mmol) was dissolved in HC1 in 1,4-dioxane (4.0 M) (1 mL) and the mixture was stirred at room temperature for 1 h. The resulting mixture was concentrated under vacuum. The crude product (40 mg) was purified by Prep-HPLC with the following conditions: (Column: XBridge Prep Phenyl OBD Column 19*250 mm, 5 pm; Mobile Phase A: Water (10 mmol/L NH4HCO3), Mobile Phase B: ACN; Flow rate: 20 mL/min; Gradient (B%): 44% B to 54% B in 10 min; Wave Length: 254/220 nm; RTl(min): 10) to afford ((3R,8R)-4-amino-3-methyl-

1.3.6.7.8.9-hexahydrofuro[3,4-c][l,7]naphthyridin-8-yl)((4R*,4aR*,9bR*)-4-methyl-7- (trifhioromethyl)-3,4,4a,9b-tetrahydrofuro[2,3-b:4,5-b']dipyridin-l(2H)-yl)methanone, isomer 2 (Example 102) (9.8 mg, 26%) as a white solid. MS (ESI) calc’d for C24H26F3N5O3 [M+H]⁺, 490.20; found, 490.20. 'H NMR (400 MHz, DMSO-d₆) 57.96 - 7.85 (m, 1H), 7.62 - 7.43 (m, 1H), 6.23 - 6.18 (m, 1H), 5.68 (br, 2H), 5.22 (br, 1H), 4.98 - 4.65 (m, 3H), 4.43 - 3.98 (m, 2H), 3.78 - 3.62 (m, 2H), 2.98 - 2.71 (m, 3H), 2.35 - 2.32 (m, 2H), 1.78 - 1.62 (m, 2 H), 1.35 - 1.32 (m, 3H), 1.11 - 1.08 (m, 3H).

Example 104: ((3R,8R)-4-amino-3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4- c][l,7]naphthyridin-8-yl)((2R*,3S,4aS*,9bS*)-3-methoxy-2-methyl-7-(trifluoromethyl)-

3,4,4a,9b-tetrahydrofuro[2,3-b:4,5-b']dipyridin-l(2H)-yl)methanone, isomer 1

Example 105: ((3R,8R)-4-amino-3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4- c][l,7]naphthyridin-8-yl)((2R*,3S,4aS*,9bS*)-3-methoxy-2-methyl-7-(trifluoromethyl)- 3,4,4a,9b-tetrahydrofuro[2,3-b:4,5-b']dipyridin-l(2H)-yl)methanone, isomer 2

[1879] To a mixture of intermediate A87 (82.5 lmg, 0.29 mmol) and intermediate CA6 isomer 3 (100 mg, 0.29 mmol) in DMAc (2 mL) were added DIEA (73.99 mg, 0.57 mmol) and BOPCI (145.72 mg, 0.57 mmol). The resulting mixture was stirred at room temperature for lh. The residue was purified by reversed-phase flash column chromatography with 30 - 80% MeCN in Water to afford a 1:1 mixture of tert-butyl (3R,8R)-4-amino-8- ((2R*,3S,4aS*,9bS*)-3-methoxy-2-methyl-7-(trifluoromethyl)-l,2,3,4,4a,9b- hexahydrofuro[2,3-b:4,5-b']dipyridine-l-carbonyl)-3-methyl-3,6,8,9-tetrahydrofuro[3,4- c][l,7]naphthyridine-7(lH)-carboxylate isomer 1 and tert-butyl (3R,8R)-4-amino-8- ((2R*,3S,4aS*,9bS*)-3-methoxy-2-methyl-7-(trifluoromethyl)-l,2,3,4,4a,9b- hexahydrofuro[2,3-b:4,5-b']dipyridine-l-carbonyl)-3-methyl-3,6,8,9-tetrahydrofuro[3,4- c][l,7]naphthyridine-7(lH)-carboxylate isomer 2 (20 mg, 11%) as a white solid. [1880] A mixture of 1:1 mixture of tert-butyl (3R,8R)-4-amino-8-((2R*,3S,4aS*,9bS*)-3- methoxy-2-methyl-7-(trifluoromethyl)-l,2,3,4,4a,9b-hexahydrofuro[2,3-b:4,5-b']dipyridine- 1 -carbonyl)-3-methyl-3,6,8,9-tetrahydrofuro[3,4-c] [ l,7]naphthyridine-7(lH)-carboxylate isomer 1 and tert-butyl (3R,8R)-4-amino-8-((2R*,3S,4aS*,9bS*)-3-methoxy-2-methyl-7- (trifluoromethyl)-l,2,3,4,4a,9b-hexahydrofuro[2,3-b:4,5-b']dipyridine-l-carbonyl)-3-methyl- 3,6,8,9-tetrahydrofuro[3,4-c][l,7]naphthyridine-7(lH)-carboxylate isomer 2 (20 mg, 0.03 mmol) and HC1 (g) (4.0 M in 1,4-dioxane, 3 mL) was stirred at room temperature for 1 h. The resulting mixture was concentrated under vacuum. The crude product was purified by Prep- HPLC with the following conditions: (Column: XBridge Prep Phenyl OBD Column 19*250 mm, 5pm; Mobile Phase A: Water (lOmmol/L NH4HCO3), Mobile Phase B: ACN; Flow rate: 20 mL/min; Gradient (B%): 41% B to 51% B in 10 min; Wave Length: 254/220 nm; RTl(min): 15) to afford a 1:1 mixture of mixture of tert-butyl (3R,8R)-4-amino-8- ((2R*,3S,4aS*,9bS*)-3-methoxy-2-methyl-7-(trifluoromethyl)-l,2,3,4,4a,9b- hexahydrofuro[2,3-b:4,5-b']dipyridine-l-carbonyl)-3-methyl-3,6,8,9-tetrahydrofuro[3,4- c][l,7]naphthyridine-7(lH)-carboxylate and tert-butyl (3R,8R)-4-amino-8- ((2R*,3S,4aS*,9bS*)-3-methoxy-2-methyl-7-(trifluoromethyl)-l,2,3,4,4a,9b- hexahydrofuro[2,3-b:4,5-b']dipyridine-l-carbonyl)-3-methyl-3,6,8,9-tetrahydrofuro[3,4- c][l,7]naphthyridine-7(lH)-carboxylate isomer 1 and mixture of tert-butyl (3R,8R)-4-amino- 8-((2R*,3S,4aS*,9bS*)-3-methoxy-2-methyl-7-(trifluoromethyl)-l,2,3,4,4a,9b- hexahydrofuro[2,3-b:4,5-b']dipyridine-l-carbonyl)-3-methyl-3,6,8,9-tetrahydrofuro[3,4- c][l,7]naphthyridine-7(lH)-carboxylate and tert-butyl (3R,8R)-4-amino-8- ((2R*,3S,4aS*,9bS*)-3-methoxy-2-methyl-7-(trifluoromethyl)-l,2,3,4,4a,9b- hexahydrofuro[2,3-b:4,5-b']dipyridine-l-carbonyl)-3-methyl-3,6,8,9-tetrahydrofuro[3,4- c][l,7]naphthyridine-7(lH)-carboxylate isomer 2 (6.3 mg, 37%) as a white solid.

[1881] This 1:1 mixture (6.3 mg) was separated by chiral-Prep-HPLC with the following conditions: (Column: CHIRALPAK IH, 2*25 cm, 5 pm; Mobile Phase A: Hex (0.5% 2M NH₃-MeOH)- HPLC, Mobile Phase B: MeOH: EtOH=l: 1-HPLC; Flow rate: 20 mL/min; Gradient (B%): 20% B to 20% B in 13 min% B; Wave Length: 220/254 nm; RTl(min): 8.317; RT2(min): 11.094; Sample Solvent: MeOH: EtOH=l: 1— HPLC; Injection Volume: 1.0 mL; Number Of Runs: 2) to afford ((3R,8R)-4-amino-3-methyl-l,3,6,7,8,9- hexahydrofuro[3,4-c][l,7]naphthyridin-8-yl)((2R*,3S,4aS*,9bS*)-3-methoxy-2-methyl-7- (trifhioromethyl)-3,4,4a,9b-tetrahydrofuro[2,3-b:4,5-b']dipyridin-l(2H)-yl)methanone, isomer 1 (Example 104) (1.2 mg) as a white solid with retetntion time at 8.317 min on prep- Chiral HPLC and((3R,8R)-4-amino-3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4- c][l,7]naphthyridin-8-yl)((2R*,3S,4aS*,9bS*)-3-methoxy-2-methyl-7-(trifluoromethyl)- 3,4,4a,9b-tetrahydrofuro[2,3-b:4,5-b']dipyridin-l(2H)-yl)methanone, isomer 2 (Example 105) (1.6 mg) as a white solid.

[1882] ((3R,8R)-4-amino-3-methyl-l ,3,6,7,8,9-hexahydrofuro[3,4-c] [1 ,7]naphthyridin-8- yl)((2R*,3S,4aS*,9bS*)-3-methoxy-2-methyl-7-(trifluoromethyl)-3,4,4a,9b- tetrahydrofuro[2,3-b:4,5-b']dipyridin-l(2H)-yl)methanone, isomer 1 (Example 104): MS ESI calculated for C25H28F3N5O4 [M+H]⁺, 520.22; found, 520.20. 'H NMR (400 MHz, DMSO- d₆) 5 8.04 and 7.70 (s, 1H), 7.45 - 7.43 (m, 1H), 6.57 - 6.24 (m, 1H), 5.62 (d, J = 12.0 Hz, 2H), 5.43 - 5.20 (m, 2H), 4.98 - 4.76 (m, 2H), 4.24 (t, J = 6.8 Hz, 1H), 3.98 - 3.92 (m, 1H), 3.79 - 3.77 (s, 1H), 3.69 - 3.50 (m, 1H), 3.33 and 3.26 (s, 3H), 2.15 - 2.07 (m, 1H), 2.89 - 2.87 (m, 1H), 2.62 - 2.60 (m, 1H), 2.26 - 2.12 (m, 1H), 2.04 - 2.93 (m, 1H), 1.79 - 1.68 (m, 1H), 1.33 (d, J = 6.1 Hz, 3H), 1.00 and 0.87 (d, J = 6.8 Hz, 3H).

[1883] ((3R,8R)-4-amino-3-methyl-l ,3,6,7,8,9-hexahydrofuro[3,4-c] [1 ,7]naphthyridin-8- yl)((2R*,3S,4aS*,9bS*)-3-methoxy-2-methyl-7-(trifluoromethyl)-3,4,4a,9b- tetrahydrofuro[2,3-b:4,5-b']dipyridin-l(2H)-yl)methanone, isomer 2 (Example 105): C25H28F3N5O4 [M+H]⁺, 520.22; found, 520.20. 'H NMR (400 MHz, DMSO-d₆) 5 8.13 and 7.78 (s, 1H), 7.52 (d, J = 7.2 Hz, 1H), 6.30 - 6.28 (m, 1H), 5.64 (s, 2H), 5.44 - 5.19 (m, 2H), 5.02 - 4.76 (m, 2H), 4.66 - 4.22 (m, 1H), 4.09 - 3.87 (m, 1H), 3.76 - 3.73 (m, 2H), 3.36 and 3.26 (s, 3H), 3.13 - 3.04 (m, 1H), 2.96 - 2.72 (m, 2H), 2.30 - 1.99 (m, 2H), 1.70 - 1.68 (m, 1H), 1.32 - 1.30 (m, 3H), 0.97 and 0.85 (d, J= 6.8 Hz, 2H).

Example 106: rel-((3R,8S)-4-amino-3-methyl-3,6,8,9-tetrahydro-lH-furo[3,4-d]pyrano[3,4- b]pyridin-8-yl)((3R,4aS,9bS)-3-fluoro-7-(trifluoromethyl)-3,4,4a,9b-tetrahydrofuro[2,3- b:4,5-b']dipyridin-l(2H)-yl)methanone, isomer 1 Example 107: rel-((3R,8S)-4-amino-3-methyl-3,6,8,9-tetrahydro-lH-furo[3,4-d]pyrano[3,4- b]pyridin-8-yl)((3R,4aS,9bS)-3-fluoro-7-(trifluoromethyl)-3,4,4a,9b-tetrahydrofuro[2,3- b:4,5-b']dipyridin-l(2H)-yl)methanone, isomer 2 isomer 2

Example 108: rel-((3R,8S)-4-amino-3-methyl-3,6,8,9-tetrahydro-lH-furo[3,4-d]pyrano[3,4- b]pyridin-8-yl)((3R,4aS,9bS)-3-fluoro-7-(trifluoromethyl)-3,4,4a,9b-tetrahydrofuro[2,3- b:4,5-b']dipyridin-l(2H)-yl)methanone, isomer 3 isomer 3

Example 109: rel-((3R,8S)-4-amino-3-methyl-3,6,8,9-tetrahydro-lH-furo[3,4-d]pyrano[3,4- b]pyridin-8-yl)((3R,4aS,9bS)-3-fluoro-7-(trifluoromethyl)-3,4,4a,9b-tetrahydrofuro[2,3- b:4,5-b']dipyridin-l(2H)-yl)methanone, isomer 4 isomer 4

Step-1:

[1884] To a stirred solution of intermediate A91 isomer 1 (27 mg, 0.10 mmol), intermediate CAI 2 (40 mg, 0.09 mmol) and DIEA (22. mg, 0.17 mmol) in N,N- dimethylacetamide (1 mL) was added bis(2-oxo-l,3-oxazolidin-3-yl)phosphinoyl chloride (33 mg, 0.13 mmol) at room temperature. The resulting mixture was stirred at room temperature for 2 h. The resulting mixture was quenched with water. The resulting mixture was extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SC>4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-100% ethyl acetate in petroleum ether to afford a 1 : 1 : 1: 1 mixture of tert-butyl ((3R,8S)-8-((3R*,4aS*,9bS*)-3- fluoro-7-(trifhioromethyl)-l,2,3,4,4a,9b-hexahydrofuro[2,3-b:4,5-b']dipyridine-l-carbonyl)- 3-methyl-3,6,8,9-tetrahydro-lH-furo[3,4-d]pyrano[3,4-b]pyridin-4-yl)(4- methoxybenzyl)carbamate and tert-butyl ((3S,8R)-8-((3R*,4aS*,9bS*)-3-fluoro-7- (trifhioromethyl)-l,2,3,4,4a,9b-hexahydrofuro[2,3-b:4,5-b']dipyridine-l-carbonyl)-3-methyl- 3,6,8,9-tetrahydro-lH-furo[3,4-d]pyrano[3,4-b]pyridin-4-yl)(4-methoxybenzyl)carbamate and tert-butyl ((3R,8R)-8-((3R*,4aS*,9bS*)-3-fluoro-7-(trifluoromethyl)-l,2,3,4,4a,9b- hexahydrofuro[2,3-b:4,5-b']dipyridine-l-carbonyl)-3-methyl-3,6,8,9-tetrahydro-lH-furo[3,4- d]pyrano[3,4-b]pyridin-4-yl)(4-methoxybenzyl)carbamate and tert-butyl ((3S,8S)-8- ((3R*,4aS*,9bS*)-3-fluoro-7-(trifluoromethyl)-l,2,3,4,4a,9b-hexahydrofuro[2,3-b:4,5- b']dipyridine-l-carbonyl)-3-methyl-3,6,8,9-tetrahydro-lH-furo[3,4-d]pyrano[3,4-b]pyridin-4- yl)(4-methoxybenzyl)carbamate. MS ESI calculated C36H38F4N4O7 [M+H] ⁺, 715.27; found, 715.25. Step-2:

[1885] A solution of 1 : 1 : 1 : 1 mixture of tert-butyl ((3R,8S)-8-((3R*,4aS*,9bS*)-3-fhioro-7- (trifluoromethyl)-l,2,3,4,4a,9b-hexahydrofuro[2,3-b:4,5-b']dipyridine-l-carbonyl)-3-methyl- 3,6,8,9-tetrahydro-lH-furo[3,4-d]pyrano[3,4-b]pyridin-4-yl)(4-methoxybenzyl)carbamate and tert-butyl ((3S,8R)-8-((3R*,4aS*,9bS*)-3-fluoro-7-(trifluoromethyl)-l,2,3,4,4a,9b- hexahydrofuro[2,3-b:4,5-b']dipyridine-l-carbonyl)-3-methyl-3,6,8,9-tetrahydro-lH-furo[3,4- d]pyrano[3,4-b]pyridin-4-yl)(4-methoxybenzyl)carbamate and tert-butyl ((3R,8R)-8- ((3R*,4aS*,9bS*)-3-fluoro-7-(trifluoromethyl)-l,2,3,4,4a,9b-hexahydrofuro[2,3-b:4,5- b']dipyridine-l-carbonyl)-3-methyl-3,6,8,9-tetrahydro-lH-furo[3,4-d]pyrano[3,4-b]pyridin-4- yl)(4-methoxybenzyl)carbamate and tert-butyl ((3S,8S)-8-((3R*,4aS*,9bS*)-3-fluoro-7- (trifluoromethyl)-l,2,3,4,4a,9b-hexahydrofuro[2,3-b:4,5-b']dipyridine-l-carbonyl)-3-methyl- 3,6,8,9-tetrahydro-lH-furo[3,4-d]pyrano[3,4-b]pyridin-4-yl)(4-methoxybenzyl)carbamate (50 mg, 0.07 mmol) in TFA (0.2 mL) was stirred at 50 °C for 16 h. The resulting mixture was concentrated under reduced pressure. The residue was purified by reversed-phase flash column chromatography with 3% to 80% MeCN in Water (0.1% TFA) and then further purified by Prep-Chiral-HPLC with the following conditions (Column: CHIRALPAK ID, 2*25 cm, 5 pm; Mobile Phase A: Hex(0.5% 2M NH₃-MeOH)-HPLC, Mobile Phase B: MeOH: EtOH=l: 1— HPLC; Flow rate: 20 mL/min; Gradient (B%): 20% B to 20% B in 40 min% B; Wave Length: 220/254 nm; RTl(min): 21.36; RT2(min): 24.54; RT3(min): 32.98; RT4(min): 35.26; Sample Solvent: MeOH: EtOH=l: 1— HPLC; Injection Volume: 0.8 mL; Number Of Runs: 4) to afford rel-((3R,8S)-4-amino-3-methyl-3,6,8,9-tetrahydro-lH- furo[3,4-d]pyrano[3,4-b]pyridin-8-yl)((3R,4aS,9bS)-3-fluoro-7-(trifluoromethyl)-3,4,4a,9b- tetrahydrofuro[2,3-b:4,5-b']dipyridin-l(2H)-yl)methanone, isomer 1 (Example 106) (3.9 mg, 13%) as a white solid with retention time at 21.36 min on prep-Chiral HPLC. MS ESI calculated C23H22F4N4O4 [M+H]⁺, 495.16; found, 495.20. ¹H NMR (400 MHz, DMSO-d₆) 5

8.12 - 7.43 (m, 2H), 6.14 - 5.94 (m, 1H), 5.86 (s, 2H), 5.30 - 5.20 (m, 2H), 5.13 - 4.17 (m, 7H), 3.16 - 2.53 (m, 4H), 2.22 - 2.00 (m, 1H), 1.37 - 1.28 (m, 3H).

[1886] This chiral resolution also afforded rel-((3R,8S)-4-amino-3-methyl-3,6,8,9- tetrahydro-lH-furo[3,4-d]pyrano[3,4-b]pyridin-8-yl)((3R,4aS,9bS)-3-fluoro-7- (trifhioromethyl)-3,4,4a,9b-tetrahydrofuro[2,3-b:4,5-b']dipyridin-l(2H)-yl)methanone, isomer 2 (Example 107) (3.2 mg, 11%) as a white solid with the retention time at 24.54 min on prep-Chiral HPLC. MS ESI calculated C23H22F4N4O4 [M+H]⁺, 495.16; found, 495.20. 'H NMR (400 MHz, DMSO-de) 8 8.19 - 7.46 (m, 2H), 6.22 - 6.07 (m, 1H), 5.84 (s, 2H), 5.38 - 5.21 (m, 2H), 5.15 - 4.08 (m, 7H), 3.17 - 2.54 (m, 4H), 2.20 - 1.90 (m, 1H), 1.35 - 1.30 (m, 3H).

[1887] This chiral resolution also afforded rel-((3R,8S)-4-amino-3-methyl-3,6,8,9- tetrahydro-lH-furo[3,4-d]pyrano[3,4-b]pyridin-8-yl)((3R,4aS,9bS)-3-fluoro-7- (trifhioromethyl)-3,4,4a,9b-tetrahydrofuro[2,3-b:4,5-b']dipyridin-l(2H)-yl)methanone, isomer 3 (Example 108) (4.2 mg, 14%) as a white solid with theretention time at 32.98 min on prep-Chiral HPLC. MS ESI calculated C23H22F4N4O4 [M+H]⁺, 495.16; found, 495.20. ¹H NMR (400 MHz, DMSO-d₆) 8 8.09 - 7.44 (m, 2H), 6.36 - 5.56 (m, 3H), 5.31 - 5.21 (m, 2H),

5.12 - 4.12 (m, 7H), 3.14 - 2.52 (m, 4H), 2.26 - 1.91 (m, 1H), 1.39 - 1.28 (m, 3H).

[1888] This chiral resolution also afforded rel-((3R,8S)-4-amino-3-methyl-3,6,8,9- tetrahydro-lH-furo[3,4-d]pyrano[3,4-b]pyridin-8-yl)((3R,4aS,9bS)-3-fluoro-7- (trifhioromethyl)-3,4,4a,9b-tetrahydrofuro[2,3-b:4,5-b']dipyridin-l(2H)-yl)methanone, isomer 4 (Example 109) (6.6 mg, 22%) as a white solid with the retention time at 35.26 min on prep-Chiral HPLC. MS ESI calculated C23H22F4N4O4 [M+H]⁺, 495.16; found, 495.20. ’H NMR (400 MHz, DMSO-rfg) 8 8.23 - 7.45 (m, 2H), 6.24 - 5.87 (m, 3H), 5.40 - 5.22 (m, 2H), 5.14 - 4.10 (m, 7H), 3.18 - 2.53 (m, 4H), 2.20 - 1.95 (m, 1H), 1.39 - 1.28 (m, 3H).

Example 110: ((3R,8R)-4-amino-3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4- c][l,7]naphthyridin-8-yl)((3R,4aS,9bS)-3-hydroxy-7-(trifluoromethyl)-3,4,4a,9b- tetrahydrofuro[2,3-b:4,5-b']dipyridin-l(2H)-yl)methanone

Example 61

[1889] To a stirred solution of Example 61 (5 mg, 0.01 mmol) in DCM (1 mL) was added Boron tribromide (1.0 M in DCM) (0.2 mL) at 0°C under nitrogen atmosphere. The resulting mixture was stirred at 40 °C for 12 h. The reaction was quenched with water at 0 °C and concentrated under vacuum. The crude residue was purified by reversed-phase flash column chromatography with 10% to 60% MeCN in Water (10 mmol/L NH4HCO3) to afford ((3R,8R)-4-amino-3-methyl-l ,3,6,7,8,9-hexahydrofuro[3,4-c] [1 ,7]naphthyridin-8- yl)((3R,4aS,9bS)-3-hydroxy-7-(trifhioromethyl)-3,4,4a,9b-tetrahydrofuro[2,3-b:4,5- b']dipyridin-l(2H)-yl)methanone (Example 110) (0.7 mg, 14%) as a white solid. MS ESI calculated for C23H24F3N5O4 [M+H]⁺, 492.18; found. 492.20.

Example 111: ((3R,8R)-4-amino-3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4- c][l,7]naphthyridin-8-yl)((3R,4aR*,10bR*)-8-(difluoromethoxy)-3-hydroxy-2,3,4,4a,6,10b- hexahydro- 1 H-pyrano [3 ,2-b : 5 ,4-b '] dipyridin- 1 -yl)methanone

Example 91

[1890] To a stirred solution of Example 91 (5 mg, 0.01 mmol) in DCM (1 mL) was added Boron tribromide (1.0 M in DCM) (0.2 mL) at 0 °C under nitrogen atmosphere. The resulting mixture was stirred at 40 °C for 12 h under nitrogen atmosphere. The reaction was quenched with water at 0 °C and concentrated under vacuum. The crude residue was purified by reversed-phase flash column chromatography with 10% to 80% MeCN in Water (10 mmol/L NH4HCO3) to afford ((3R,8R)-4-amino-3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4- c][l,7]naphthyridin-8-yl)((3R,4aR*,10bR*)-8-(difluoromethoxy)-3-hydroxy-2,3,4,4a,6,10b- hexahydro-lH-pyrano[3,2-b:5,4-b']dipyridin-l-yl)methanone (Example 111) (0.7 mg, 13%) as a white solid. MS ESI calculated for C24H27F2N5O5 [M+H]⁺, 504.20; found. 520.20.

Example 112: ((3R,8R)-4-amino-3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4- c][l,7]naphthyridin-8-yl)((3R,4aR*,9bR*)-7-(difluoromethoxy)-3-methoxy-3,4,4a,9b- tetrahydrofuro[2,3-b:4,5-b']dipyridin-l(2H)-yl)methanone

[1891] To a solution of intermediate A104 (60 mg, 0.22 mmol) and intermediate CA6, isomer 3 (77 mg, 0.22 mmol) in DMAc (2 mL) were added BOPCI (84 mg, 0.33 mmol) and EtsN (67 mg, 0.66 mmol). The resulting mixture was stirred at room temperature for overnight. The resulting mixture was quenched with water and extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SO4. After filtration, the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, eluted with 0-20% MeOH in CH2Q2 to afford tert-butyl (3R,8R)-4-amino-8-((3R,4aR*,9bR*)-7-(difluoromethoxy)-3-methoxy-l,2,3,4,4a,9b- hexahydrofuro[2,3-b:4,5-b']dipyridine-l-carbonyl)-3-methyl-3,6,8,9-tetrahydrofuro[3,4- c][l,7]naphthyridine-7(lH)-carboxylate (53 mg, 31%) as a yellow oil.

[1892] A mixture of tert-butyl (3R,8R)-4-amino-8-((3R,4aR*,9bR*)-7-(difluoromethoxy)- 3-methoxy-l,2,3,4,4a,9b-hexahydrofuro[2,3-b:4,5-b']dipyridine-l-carbonyl)-3-methyl- 3,6,8,9-tetrahydrofuro[3,4-c][l,7]naphthyridine-7(lH)-carboxylate (53 mg, 0.133 mmol) and HC1 (g) (4.0 M in 1,4-dioxane, 5 mL) was stirred at room temperature for 2 hours. The mixture was basified with saturated NaHCCh (aq.) to pH 8. The resulting mixture was concentrated under reduced pressure. The residue was purified by reversed-phase flash column chromatography with 30%~50% MeCN in water (10 mmol/L NH4HCO3) to afford ((3R,8R)-4-amino-3-methyl-l,3,6,7,8,9-hexahydrofuro[3,4-c][l,7]naphthyridin-8- yl)((3R,4aR*,9bR*)-7-(difluoromethoxy)-3-methoxy-3,4,4a,9b-tetrahydrofuro[2,3-b:4,5- b']dipyridin-l(2H)-yl)methanone (Example 112) (11.7 mg, 14%) as a white solid. MS ESI calculated for C24H27F2N5O5 [M+H]⁺, 504.20; found, 504.20. 'H NMR (300 MHz, DMSO-d₆) 5 8.10 - 7.33 (m, 2H), 6.66 - 6.57 (m, 1H), 5.98 (d, J = 8.7 Hz, 1H), 5.60 (d, J = 7.3 Hz, 2H), 5.34 - 5.08 (m, 2H), 5.02 - 4.87 (m, 1H), 4.78 (t, J = 11.9 Hz, 1H), 4.53 - 4.24 (m, 1H), 4.O2 - 3.85 (m, 1H), 3.88 - 3.51 (m, 3H), 3.23 - 3.20 (m, 3H), 2.80 - 2.62 (m, 2H), 2.50 - 2.26 (m, 2H), 2.19 - 1.96 (m, 2H), 1.32 (d, J = 6.1 Hz, 3H).

Biological Examples

Biological Example 1: PRMT5 Biochemical Assay

[1893] The PRMT5 biochemical assay was conducted in 384-well, assay-ready compound plates (PerkinElmer, Inc.; catalog number 6007290) with a final enzymatic reaction volume of 16 pL; plates were prepared a priori, starting at 10 pM with 10 concentration points in a 3- fold serial dilution series for test compounds. The controls were defined as Low Control and High Control; Low Control contained all reagents aside from PRMT5 protein, and the High Control contained all reagents plus PRMT5.

[1894] The enzymatic reaction was carried out at a final concentration of PRMT5 (in complex with MEP50, Proteros, GmbH; catalog number PR-0376) of 1.2 nM (equal to the PRMT5 monomer concentration), in a reaction mixture buffer and incubated for 60 minutes at 37 °C, in the presence and absence of 100 nM MTA (EMD Millipore, Inc.; catalog number 260585); the mixture consisted of 2 pM S-adenosyl-methionine (Promega, Inc.; catalog number V7601), 2.3 pM full-length histone H2A (New England Biolabs, Inc.; catalog number M2502) or 1.5 pM full-length histone H2A (Active Motif, Inc.; catalog number 31890) in assay buffer; assay buffer consisted of 50 mM Tris-HCl (pH 8) (ThermoFisher Scientific, Inc.; catalog number AM9856), 50 mM NaCl (ThermoFisher Scientific, Inc.; catalog number AM9759), 1 mM TCEP (Gold Biotechnology, Inc.; catalog number TCEP1), 0.01% Tween-20 (EMD Millipore, Inc.; 655206), 0.01% w/v bovine serum albumin (Perkin- Elmer, Inc.; catalog number CR84-100). After 60 minutes, the reaction was subjected to a detection procedure utilizing the MTase-Glo™ Methyltransferase Assay (Promega, Inc.; catalog number V7601). First, 4 uL of 5X MTase-Glo™ Reagent (Promega, Inc.; catalog number V7601), diluted from the original 10X stock with assay buffer, was added to added to the enzymatic reaction mixture and incubated for 30 minutes at room temperature. Second, 20 uL of 2X MTase-Glo™ Detection Solution (Promega, Inc.; catalog number V7601) was added, and the mixture was incubated for 30 minutes at room temperature. Signal was measured in a plate reader with luminescence capabilities.

[1895] Percent inhibition for each concentration of test compound was determined by calculating the ratio between the test compound, low control, and high control signals; the resulting data was fitted and the IC50 was estimated using Levenberg-Marquardt algorithm.

[1896] The IC50 of a representative number of compounds in Table 1 above are disclosed in above are disclosed in Table 2A below, where 2.3 pM full-length histone H2A (New England Biolabs, Inc.; catalog number M2502) was used:

A <= 0.1 pM; 0.1 pM < B <= 0.25 pM; 0.25 pM < C <= 0.5 pM; 0.5 pM < D <= 1.0 pM; 1.0 pM < E <= 1.5 pM

Table 2: PRMT5 Biochemical Assay Results

[1897] The IC50 of a representative number of compounds in Table 1 above are disclosed in Table 2B below, where 1.5 pM full-length histone H2A (Active Motif, Inc.; catalog number 31890) was used:

A <= 0.1 pM; 0.1 pM < B <= 0.25 pM; 0.25 pM < C <= 0.5 pM; 0.5 pM < D <= 1 .0 pM; 1 .0 pM < E <= 1.5 pM; 1.5 pM < F <= 5 pM; 5 pM < G <= 10 pM; and 10 pM < H

Table 2B: PRMT5 Biochemical Assay Results

Biological Example 2: Cell viability assay in HCT116 WT and HCT116 MTAP ''' cells

[1898] The cell viability was determined by doing cell nuclear counts; cell nuclei were labeled with a fluorescent protein kit using the manufacturer’s protocol (Sartorius).

[1899] HCT116 WT and HCT116 MTAP’⁷’ (ATCC) were cultured in DMEM/F12 with GlutaMAX (Gibco) supplemented with 10% Fetal Bovine Serum (FBS, Gibco) and 2ug/mL puromycin (Gibco). Cells were seeded in 384-well plates, at a density of 166 cells/well in 50pL of cell culture media without puromycin. Cell plates were incubated overnight at 37°C with 5% CO2. After the overnight incubation, cells were imaged in a confocal microscope with nuclear count capabilities for the pre-treatment data set.

[1900] Cells were treated starting at a 20pM in 9-points and 4-fold serial dilutions for test compounds; the negative control was DMSO. All compounds and the negative control had a final DMSO concentration of 0.2%. Cells were incubated for 5 days at 37°C with 5% CO2. On day 5, cells were imaged, and nuclei were counted for the post-treatment data set.

[1901] Percent inhibition for each concentration of test compound was determined by calculating the ratio between the post-treatment and pre-treatment nuclei count, and negative control; the resulting data was fitted and the ECso was estimated using the Levenberg- Marquardt algorithm.

[1902] The ECso of a representative number of compounds in Table 1 above are disclosed in Table 3 below:

A <= 0.1 pM; 0.1 pM < B <= 0.25 pM; 0.25 pM < C <= 0.5 pM; 0.5 pM < D <= 1.0 pM; 1.0 pM < E <= 2.0 pM; 2.0 pM < F <= 5.0 pM; 5.0 pM < G <= 10.0 pM;

10 pM < H <= 20 pM; I > 20 pM

Table 3: Cell Viability Assay Results

[1903] Although the foregoing invention has been described in some detail by way of illustration and example for purposes of clarity of understanding, one of skill in the art will appreciate that certain changes and modifications may be practiced within the scope of the appended claims. In addition, each reference provided herein is incorporated by reference in its entirety to the same extent as if each reference was individually incorporated by reference. Where a conflict exists between the instant application and a reference provided herein, the instant application shall dominate.

Claims

WHAT IS CLAIMED IS:

1. A compound of Formula (la) : or a pharmaceutically acceptable salt thereof, wherein

X¹ is C(R^laR^lb), O, or NR¹;

X² is C(R^2aR^2b), O, or NR²;

X³ is C(R^3aR^3b), O, or NR³;

X⁴ is C(R^4aR^4b), O, NR⁴, S, S(O), or S(O)₂;

X⁵ is C(R^5aR^5b), O, NR⁵, S, S(O), or S(O)₂;

X⁶ is C(R^6aR^6b), O, NR⁶, S, S(O), or S(O)₂;

R¹, R², and R³ are each independently H or Ci-4 alkyl;

R^4a , R^4b, R^5a,R^5b, R^6a, and R^6b are each independently H, C1.4 alkyl, C1-4 haloalkyl, Cu hydroxyalkyl, or C1-4 haloalkyl(OH); ring A is heterocycloalkyl having 4 to 7 ring members with at least 1 nitrogen atom ring vertex, and 0 to 2 additional heteroatoms as ring vertices, wherein each additional heteroatom is independently N, O, or S; ring B isphenyl or heteroaryl having 5 to 6 ring members with 1 to 3 heteroatom ring vertices, wherein each heteroatom is independently N, O, or S; ring C is fused to (a) two adjacent ring vertices of ring A and (b) two adjacent ring vertices of ring B; and ring C is C4-7 cycloalkyl or heterocycloalkyl having 4 to 7 ring members with 1 to 3 heteroatom ring vertices, wherein each heteroatom is independently N, O, or S; p is 0, 1, or 2; q is 0, 1, or 2; each R⁷ is independently C1-6 alkyl, Ci-6 haloalkyl, halo, OH, C1-6 alkoxy, C1.6 haloalkoxy, -C(O)Ci-₆ alkyl, -C(O)Ci-₆ haloalkyl, -C(O)OCi-₆ alkyl, or -C(O)OCi ₆ haloalkyl; each R^7a is independently Ci-4 alkyl, halo, C1-4 haloalkyl, OH, or Ci-4 alkoxy; alternatively, two R^7a groups attached to the same carbon atom combine to form oxo; each R⁸ is independently Ci-6 alkyl, Ci-6 haloalkyl, halo, OH, CN, Ci-6 alkoxy, Ci-6 haloalkoxy, C2-6 alkynyl, -O-C2-6 alkynyl, C3-6 cycloalkyl, -O-C3-6 cycloalkyl, - C(O)Ci-₆ alkyl, -C(O)Ci-₆ haloalkyl, -C(O)OCi-₆ alkyl, -C(O)OCi-₆ haloalkyl, or heterocycloalkyl having 4 to 6 ring members with 1 to 3 heteroatom ring vertices, wherein each heteroatom is independently N, O, or S, and wherein each of the C3-6 cycloalkyl, -O-C3-6 cycloalkyl, and heterocycloalkyl is substituted with 0, 1, or 2 R^8a; each R^8a is independently C1-4 alkyl, halo, C1-4 haloalkyl, CN, OH, or C1-4 alkoxy; and R⁹ is H, C1-4 alkyl, halo, or C1-4 haloalkyl.

2. The compound or a pharmaceutically acceptable salt thereof of claim 1, wherein: each R⁷ is independently Ci-6 alkyl, Ci-6 haloalkyl, halo, Ci-6 alkoxy, Ci-6 haloalkoxy, -C(O)Ci-₆ alkyl, -C(O)Ci-₆ haloalkyl, -C(O)OCi-₆ alkyl, or -C(O)OCi-₆ haloalkyl; each R^7a is independently C1-4 alkyl, halo, or C1-4 haloalkyl; alternatively, two R^7a groups attached to the same carbon atom combine to form oxo; each R⁸ is independently Ci-6 alkyl, Ci-6 haloalkyl, halo, CN, Ci-6 alkoxy, Ci-6 haloalkoxy, C3- 6 cycloalkyl, -O-C3-6 cycloalkyl, -C(O)Ci-6 alkyl, -C(O)Ci-6 haloalkyl, -C(O)OCi-6 alkyl, -C(O)OCi-6 haloalkyl, or heterocycloalkyl having 4 to 6 ring members with 1 to 3 heteroatom ring vertices, wherein each heteroatom is independently N, O, or S, and wherein the heterocycloalkyl is substituted with 0, 1, or 2 R^8a; each R^8a is independently C1-4 alkyl, halo, or C1-4 haloalkyl; and R⁹ is H, Ci-4 alkyl, halo, or CM haloalkyl.

3. The compound or a pharmaceutically acceptable salt thereof of claim 1 or 2, wherein X¹ is CH₂; X² is O, NH, or CH₂; X³ is CH₂; X⁴ is CHR^4a; X⁵ is O; X⁶ is CH₂; and R⁹ is H.

4. The compound or a pharmaceutically acceptable salt thereof of any one of claims 1 to 3, wherein X² is O.

5. The compound or a pharmaceutically acceptable salt thereof of any one of claims 1 to 3, wherein X² is NH.

6. The compound or a pharmaceutically acceptable salt thereof of any one of claims 1 to 3, wherein X² is CH2.

7. The compound or a pharmaceutically acceptable salt thereof of any one of claims 1 to 6, wherein ring A is heterocycloalkyl having 5 to 7 ring members with at least 1 nitrogen atom and 0 to 1 additional heteroatom as ring vertices, wherein each additional heteroatom is independently N or O; ring B is phenyl or heteroaryl having 6 ring members with 1 to 2 nitrogen atom ring vertices; and ring C is C5-6 cycloalkyl or heterocycloalkyl having 5 to 7 ring members with 1 heteroatom ring vertex, wherein the heteroatom is N or O.

8. The compound or a pharmaceutically acceptable salt thereof of any one of claims 1 to 7, wherein ring A is pyrrolidinyl, piperidinyl, piperazinyl, morpholinyl, or oxazepanyl.

9. The compound or a pharmaceutically acceptable salt thereof of any one of claims 1 to 8, wherein ring A is piperidinyl, piperazinyl, or morpholinyl.

10. The compound or a pharmaceutically acceptable salt thereof of any one of claims 1 to 9, wherein ring B is phenyl, pyridyl, pyrazinyl, pyrimidinyl, or pyridazinyl.

11. The compound or a pharmaceutically acceptable salt thereof of any one of claims 1 to 10, wherein ring C is C5-6 cycloalkyl, tetrahydrofuranyl, tetrahydropyranyl, or oxepanyl.

12. The compound or a pharmaceutically acceptable salt thereof of any one of claims 1 to 11, wherein ring C is C5-6 cycloalkyl, tetrahydrofuranyl, or tetrahydropyranyl.

13. The compound or a pharmaceutically acceptable salt thereof of any one of claims 1 to 12, having Formula (Ila):

wherein: ring B is phenyl, pyridyl, pyrazinyl, pyrimidinyl, or pyridazinyl;

X^a is O, NH, NR⁷, CH₂, CHR⁷, or C(R⁷)₂;

X^7a is absent, O, CH₂, or CHR^7a; and

14. The compound or a pharmaceutically acceptable salt thereof of any one of claims 1 to 13, wherein ring B is phenyl or pyridyl.

15. The compound or a pharmaceutically acceptable salt thereof of any one of claims 1 to 14, having Formula (Ila- 1): wherein:

X^a is O, NH, N(CI-₄ alkyl), CH₂, CHR⁷, or C(R⁷)₂;

X^7a is absent, O, CH₂, or CHR^7a; and

16. The compound or a pharmaceutically acceptable salt thereof of any one of claims 1 to 14, having Formula (IIa-2):

wherein:

X^a is O, NH, N(CI-₄ alkyl), CH₂, CHR⁷, or C(R⁷)₂;

X^7a is absent, O, CH₂, or CHR^7a; and

17. The compound or a pharmaceutically acceptable salt thereof of any one of claims 1 to 16, wherein R^4a is H or CM alkyl.

18. The compound or a pharmaceutically acceptable salt thereof of any one of claims 1 to 17, wherein R^4a is H; or R^4a is methyl.

19. The compound or a pharmaceutically acceptable salt thereof of any one of claims 13 to 18, wherein X^a is CH₂, CHR⁷, or C(R⁷)₂.

20. The compound or a pharmaceutically acceptable salt thereof of any one of claims 13 to 18, wherein:

X^a is O, NH, CH₂, or CHR⁷;

X^7a is O, CH₂, or CHR^7a;

X^7b is O, CH₂, or CHR^7a; and p is 0 or 1.

21. The compound or a pharmaceutically acceptable salt thereof of any one of claims 13 to 18, wherein:

X^a is O, NH, or CH₂;

X^7a is O, CH₂, or CHR^7a;

X^7b is O, CH₂, or CHR^7a; and p is 0, 1, or 2.

22. The compound or a pharmaceutically acceptable salt thereof of any one of claims 13 to 18, wherein:

X^a is C(R⁷)₂;

X^7a is O, CH₂, or CHR^7a;

X^7b is O, CH₂, or CHR^7a; and p is 0.

23. The compound or a pharmaceutically acceptable salt thereof of any one of claims 13 to 22, wherein:

X^7a is absent and X^7b is CH₂; or

X^7a is absent and X^7b is O.

24. The compound or a pharmaceutically acceptable salt thereof of any one of claims 1 and 3 to 23, wherein each R⁷ is independently Ci-4 alkyl, halo, OH, or Ci-4 alkoxy.

25. The compound or a pharmaceutically acceptable salt thereof of any one of claims 1 and 3 to 24, wherein each R⁷ is independently methyl, fluoro, OH, or methoxy.

26. The compound or a pharmaceutically acceptable salt thereof of any one of claims 1 to 25, wherein each R⁷ is independently methyl, fluoro, or methoxy.

27. The compound or a pharmaceutically acceptable salt thereof of any one of claims 1 and 3 to 26, wherein each R⁸ is independently Ci-6 alkyl, Ci-6 haloalkyl, halo, OH, Ci-6 alkoxy, Ci-6 haloalkoxy, CN, C₂-6 alkynyl, -O-C₂-6 alkynyl, C₃-6 cycloalkyl, or -O-C₃-6 cycloalkyl, wherein the C₃-6 cycloalkyl and -O-C₃-6 cycloalkyl are each independently substituted with 0 or 1 CN.

28. The compound or a pharmaceutically acceptable salt thereof of any one of claims 1 and 3 to 27, wherein q is 1; and R⁸ is Ci-6 alkyl, Ci-6 haloalkyl, halo, OH, Ci-6 alkoxy, Ci-6 haloalkoxy, CN, C2-6 alkynyl, -O-C2-6 alkynyl, C3-6 cycloalkyl, or -O-C3-6 cycloalkyl, wherein the C3-6 cycloalkyl and -O-C3-6 cycloalkyl are each independently substituted with 0 or 1 CN.

29. The compound or a pharmaceutically acceptable salt thereof of any one of claims 1 and 3 to 28, wherein q is 1; and R⁸ is chloro, CN, isopropyl, methoxy, fluoromethyl, difluoromethyl, trifluoromethyl, fluoromethyl-O-, difluoromethyl-O-, trifluoromethyl-O-, cyclopropyl, NC-cyclopropyl-, cyclopropyl-O-, HC=C-, or HC=C- CH2-O-.

30. The compound or a pharmaceutically acceptable salt thereof of any one of claims 1 to 29, wherein q is 1; and R⁸ is chloro, trifluoromethyl, or difluoromethyl-O-.

31. The compound or a pharmaceutically acceptable salt thereof of any one of claims 1 to 27, wherein q is 2; and each R⁸ is independently fluoro, chloro, methoxy, trifluoromethyl, or difluoromethyl-O-.

32. The compound or a pharmaceutically acceptable salt thereof of any one of claims 1 and 3 to 31, wherein the moiety

wherein:

X^a is O, NH, CH₂, or CHR⁷;

X^7a is O, CH₂, or CHR^7a;

X^7b is O, CH₂, or CHR^7a; each R^7a is independently Ci-4 alkyl; each R⁷ is independently F, OH, Ci-4 alkyl, or Ci-4 alkoxy; and

R⁸ is Ci-4 alkyl, Ci-4 haloalkyl, halo, CN, Ci-4 alkoxy, C haloalkoxy, C₂-4 alkynyl, - O-C₂-4 alkynyl, C₃-6 cycloalkyl, or -O-C₃-6 cycloalkyl, wherein the C₃-6 cycloalkyl and -O- C₃-6 cycloalkyl are each independently unsubstituted or substituted with CN, provided that X^7a and X^7b are not each O.

33. The compound or a pharmaceutically acceptable salt thereof of claim 32, wherein X^a is O, NH, CH₂, CHF, C(CH₃), C(OH), or C(OCH₃); X^7a is O, CH₂, or CH(CH₃); X^7b is O or CH₂; R⁷ is F, CH₃, OH, or OCH₃; and R⁸ is chloro, CN, isopropyl, methoxy, fluoromethyl, difluoromethyl, trifluoromethyl, fluoromethyl-O-, difluoromethyl- O- , trifluoromethyl-O-, cyclopropyl, NC-cyclopropyl-, cyclopropyl-O-, HC=C-, or HC=C-CH₂-O-, provided that X^7a and X⁷¹¹ are not each O.

34. The compound or a pharmaceutically acceptable salt thereof of claim

32 or 34, wherein R⁸ is chloro, trifluoromethyl, or difluoromethyl-O-.

35. The compound or a pharmaceutically acceptable salt thereof of any one of claims 1 to 34, wherein

X₂ is O and R^4a is H;

X₂ is NH and R^4a is H;

X₂ is NH and R^4a is methyl;

X₂ is CH₂ and R^4a is H; or

X₂ is CH₂ and R^4a is methyl.

36. The compound or a pharmaceutically acceptable salt thereof of any one of claims 1 to 35, wherein:

37. The compound or a pharmaceutically acceptable salt thereof of claim

1, represented by any one of the structures of Examples 1 to 3 and 5 to 112 in Table 1.

38. A compound or a pharmaceutically acceptable salt thereof, represented by any one of the structures of Examples 1 to 112.

39. A pharmaceutical composition comprising a compound or a pharmaceutically acceptable salt thereof of any one of claims 1 to 38, and a pharmaceutically acceptable excipient.

40. A method for treating a disease treatable by inhibition of protein arginine N-methyltransferase 5 (PRMT5) in a patient in need thereof, comprising administering to the patient a therapeutically effective amount of a compound or a pharmaceutically acceptable salt thereof of any one of claims 1 to 38, or a pharmaceutical composition of claim 39.

41. The method of claim 40, wherein the disease is cancer.

42. A method of treating an MTAP null cancer in a patient in need thereof, comprising administering to the patient a therapeutically effective amount of a compound or a pharmaceutically acceptable salt thereof of any one of claims 1 to 38, or a pharmaceutical composition of claim 39.

43. A method for treating cancer in a patient in need thereof, wherein the cancer is characterized by a reduction or absence of MTAP gene expression, an absence of the MTAP gene, an absence of MTAP protein, a reduced level of MTAP protein, a reduced function of MTAP protein, or a combination thereof, comprising administering to the patient a therapeutically effective amount of a compound or pharmaceutically acceptable salt thereof of any one of claims 1 to 38, or a pharmaceutical composition of claim 39.

44. A method of treating cancer in a patient in need thereof, comprising administering to the patient a therapeutically effective amount of a compound or a pharmaceutically acceptable salt thereof of any one of claims 1 to 38, or a pharmaceutical composition of claim 39.

45. The method of any one of claims 41 to 44, wherein the cancer is a MTA-accumulating cancer.

46. The method of claim 41 or 45, wherein the cancer is deficient in CDKN2A.

47. The method of any one of claims 41 to 46, wherein the cancer is a solid tumor.

48. The method of claim 47, wherein the solid tumor is malignant.

49. The method of any one of claims 41 to 48, wherein the cancer is biliary tract cancer, glioblastoma, ovarian cancer, malignant peripheral nerve sheath tumors (MPNST), colon cancer, esophageal cancer (e.g., esophageal squamous cell carcinoma or esophageal adenocarcinoma), gastric cancer, bladder cancer (e.g., bladder urothelial carcinoma, gallbladder cancer), pancreatic cancer (e.g., pancreatic adenocarcinoma), mesothelioma, melanoma, lung cancer e.g., non-small cell lung cancer (NSCLC); e.g., lung squamous or lung adenocarcinoma)), astrocytoma, undifferentiated pleiomorphic sarcoma, lymphoma (e.g., diffuse large B-cell lymphoma (DLBCL)), leukemia, head and neck cancer (e.g., head and neck squamous cell carcinoma), stomach adenocarcinoma, myxofibrosarcoma, cholangiosarcoma, cancer of the brain, stomach, kidney, breast, endometrium, urinary tract, liver, soft tissue, pleura and large intestine, or sarcoma.

50. The method of any one of claims 41 to 48, wherein the cancer is selected from the group consisting of leukemia, esophageal cancer, glioma, melanoma, pancreatic, non-small cell lung cancer, bladder cancer, astrocytoma, osteosarcoma, head and neck cancer, myxoid chondrosarcoma, ovarian cancer, endometrial cancer, breast cancer, soft tissue sarcoma, non-Hodgkin lymphoma, and mesothelioma.

51. The method of any one of claims 41 to 48, wherein the cancer is selected from the group consisting of non-small cell lung cancer (squamous and adenocarcinoma), urothelial cancer (bladder and upper urinary tract), esophageal cancer, and gastric cancer.

52. A method of inhibiting protein arginine N-methyltransferase 5 (PRMT5) in vivo in a patient, said method comprising administering to said patient an effective amount of a compound or a pharmaceutically acceptable salt thereof of any one of claims 1 to 38, or a pharmaceutical composition of claim 39.

53. A method of inhibiting cell proliferation, in vitro or in vivo, said method comprising contacting a cell with an effective amount of a compound or a pharmaceutically acceptable salt thereof of any one of claims 1 to 38, or a pharmaceutical composition of claim 39.

54. A method for inhibiting PRMT5 activity in a cell, comprising contacting the cell in which inhibition of PRMT5 activity is desired with an effective amount of a compound or pharmaceutically acceptable salt thereof of any one of claims 1 to 38, or a pharmaceutical composition of claim 39.