CN107216242A - A kind of method of iron catalysis oxidation alkyl aromatic compound synthesis aromatic aldehyde, arone and aromatic ester - Google Patents

Abstract

The invention discloses a method for synthesizing aromatic aldehydes, aromatic ketones and aromatic esters by iron-catalyzed oxidation of alkyl aromatic compounds, belonging to the technical field of catalytic synthesis. The invention uses a cheap and environment-friendly iron catalyst under normal pressure to oxidize the side chain of aromatic hydrocarbon to carbonyl to generate corresponding aromatic aldehydes, aromatic ketones and aromatic esters under the action of a hydrogen silicon reagent as a promoter and an oxidizing agent. The method for preparing aromatic aldehydes, aromatic ketones, and aromatic esters by catalytic oxidation reaction of the present invention has many advantages: catalysts, reaction raw materials, oxidants, and silicon reagents have a wide range of sources, are cheap, environmentally friendly, and have good stability; alkyl aromatic compounds are metered to participate in the reaction; reaction Mild conditions, functional group compatibility and wide application range; good reaction selectivity, under optimized reaction conditions, the separation yield of the target product can be as high as about 95%.

Description

An iron-catalyzed oxidation of alkylaromatic compounds to synthesize aromatic aldehydes, aromatic ketones, and aromatic esters method

technical field

The invention belongs to the technical field of catalytic synthesis, and more specifically relates to a method for iron-catalyzed synthesis of aromatic aldehydes, aromatic ketones and aromatic esters. Methods for aryl aldehydes, aryl ketones and aryl esters.

Background technique

Aromatic aldehydes, aryl ketones and aryl esters are organic synthesis intermediates with high added value, which are widely used in the synthesis of medicines, pesticides, dyes and fragrances. Among the current methods for the synthesis of aromatic aldehydes, aromatic ketones, and aromatic esters, the liquid-phase catalytic oxidation of benzylic carbon-hydrogen reactions with alkylaromatics as substrates using iron catalysts has attracted widespread attention because of the cheap catalysts and environmental friendliness of the method; Wide, stable and cheap material sources; advantages of high atom economy and low emissions. However, there are some challenging problems in this method: the reaction requires complex catalysts, the catalytic efficiency is not high, and most of the substrates are active compounds with benzylic carbon-hydrogen acidity; inert substrates such as methylbenzene compounds participate in the reaction Low efficiency, poor selectivity and the amount of solvent involved in the reaction hinder the widespread application of iron-catalyzed benzylic carbon-hydrogen oxidation in practical organic synthesis (Jian-Bo Feng, Xiao-Feng Wu, Appl.Organometal.Chem.2015 ,29,63–86).

Contents of the invention

Purpose of the invention: In view of the fact that the existing synthetic methods of aromatic aldehydes, aromatic ketones and aromatic esters through the iron-catalyzed oxidation of alkyl aromatics benzylic carbon-hydrogen bonds need to use complex ligands, resulting in high reaction costs, low reaction efficiency, and poor selectivity (especially It is the problem of peroxidation and overreduction in oxidized methylbenzene compounds, which has not been solved) the amount of solvent participating in the reaction and/or the challenging problem of poor compatibility of functional groups and narrow scope of application. The present invention provides a simple and easy-to-use and Inexpensive iron catalysts, cheap and environmentally friendly oxidants, under the action of safe and stable accelerators, efficiently and selectively catalyze the oxidation of benzylic carbon-hydrogen bonds in alkylaromatics to synthesize aromatic aldehydes, aromatic ketones, and aromatic esters. The method has good versatility, compatibility of sensitive functional groups and can effectively realize the post-stage oxidative carbonylation of complex molecules.

Technical solution: In order to solve the above problems, the technical solution adopted in the present invention is as follows:

A method for the synthesis of aromatic aldehydes, aryl ketones and aryl esters by iron-catalyzed oxidation of alkyl aromatic compounds, the method uses iron as a catalyst, and under the combined action of hydrosilane as a promoter and an oxidizing agent, oxidizes a measured amount of alkyl aromatic compounds , to prepare aromatic aldehydes, aromatic ketones and aromatic esters, the general reaction formula is as follows:

The general structural formula of the synthesized aromatic aldehyde, aromatic ketone and aromatic ester product of the method of the present invention is:

In the formula, the aryl represented by Ar is substituted or unsubstituted phenyl, biphenyl, naphthyl, anthracenyl, phenanthrenyl or pyrenyl; the heteroaryl represented by Ar is five to ten containing N, O or S A three-membered heteroaryl. R represents hydrogen, aryl, heteroaryl, alkyl, alkoxy or aryloxy.

Further, the heteroaryl represented by Ar is substituted or unsubstituted furyl, benzofuryl, thienyl, pyrrolyl, indolyl, pyridyl, isoxazolyl, pyrazolyl, imidazolyl, Oxazolyl or Thiazolyl.

Further, the aryl represented by R is substituted or unsubstituted phenyl, biphenyl, naphthyl, anthracenyl, phenanthrenyl or pyrenyl; the heteroaryl represented by R is substituted or unsubstituted furyl, benzo Furyl, thienyl, pyrrolyl, indolyl, pyridyl, isoxazolyl, pyrazolyl, imidazolyl, oxazolyl or thiazolyl; the alkyl represented by R is C1～C20 straight chain or branched Alkyl group; the alkoxy group represented by R is C1～C20 straight chain or branched chain alkoxy group; the aryloxy group represented by R is substituted or unsubstituted phenoxy group, biphenyloxy group, naphthyl group, anthracene group Base, phenanthryloxy, pyreneoxy, furyloxy, benzofuryloxy, thienyloxy, pyrroleoxy, indyloxy, pyridyloxy, isoxazolyloxy, pyrazolyloxy, imidazoleoxy group, oxazolyloxy or thiazolyloxy.

Further, when the aryl group represented by Ar or R is a substituted aryl group, the substituents on it are monosubstituted or multi-substituted hydrogen on the aromatic ring, and the substituents are arbitrarily selected from hydrogen, C1-C20 straight chain or Branched hydrocarbon group, C1~C30 straight chain or branched alkoxyl group, C1~C30 straight chain or branched chain alkylmercapto group, aryl group, heteroaryl group, hydroxyl group, carboxyl group, -B(OH) ₂ , fluorine, Chlorine, bromine, iodine, alkanoyloxy or aroyloxy.

Further, when the heteroaryl group represented by Ar or R is pyrrolyl, imidazolyl, indolyl and pyrazolyl, the substituent on the nitrogen atom is arbitrarily selected from hydrogen, C1～C12 straight chain or branched chain Alkyl, C3-C12 cycloalkyl, aryl, p-toluenesulfonyl, acetyl, benzoyl or tert-butoxyacyl.

Further, the iron catalyst is selected from iron powder, ferrous trifluoromethanesulfonate, ferric trifluoromethanesulfonate, ferrous chloride, ferrous acetylacetonate, iron acetylacetonate, 2,2,6,6-tetrafluoromethanesulfonate Methyl-3,5-heptanedionate ferrous, 2,2,6,6-tetramethyl-3,5-heptanedionate ferrous, 1,3-diphenylpropanedione ferrous, 1,3 -Iron diphenylpropanedione, ferrous benzoylacetonate, ferric benzoylacetonate, ferric ferricyanide, ferric ferricyanide, ferrous acetate, ferrous sulfate, ammonium ferrous sulfate, ferric sulfate, phthalein Ferrocyanine, ferrocene, ferrous fluoride, ferric fluoride, ferrous bromide, ferric bromide, ferrous iodide, ferric iodide, ferric chloride, ferric oxide, or ferric oxide.

Further, the hydrosilane is triethylsilane, triethoxysilane, polymethylhydrosiloxane, triisopropylsilane, dimethylphenylsilane, monophenylsilane, diphenylsilane , triphenylsilane or 1,1,3,3-tetramethyldisiloxane, dimethylethoxysilane, dimethylethylsilane, benzyldimethylsilane, diethylsilane, two Chlorophenyl silane, dimethyl monochlorosilane, diisopropyl chlorosilane, chloromethyl (dimethyl) silane, di-tert-butyl chlorosilane, diphenyl chlorosilane, ethyl dichlorosilane, di tert-butylsilane, methyldiphenylsilane, methyldichlorosilane, tert-butyldimethylsilane, 1,4-bis(dimethylsilyl)benzene, isopropoxyphenylsilane, methyl Diethoxysilane, Dimethoxy(methyl)silane, Dimethylmethylhydrogen (siloxane and polysiloxane), 1,1,3,3-Tetraisopropyldisiloxane , Tris(trimethylsilyl)silane, methylphenyl silicone oil, pentamethyldisiloxane, tetrakis(dimethylsilyl)silane, 1,3-bis(3,3,3-trifluoropropyl)- 1,1,3,3-Tetramethyldisiloxane, tetrakis(dimethylsiloxy)silane, phenyltris(dimethylsiloxy)silane or 1,1,2,2- Tetraphenyldisilane.

Further, the oxidant is oxygen, hydrogen peroxide, peracetic acid, potassium peroxodisulfate compound salt, potassium peroxosulfate, ammonium peroxosulfate or sodium peroxosulfate; when oxygen is the oxidant, the gas pressure is 0.5-2.0 Atmospheric pressure, preferably 1 atmospheric pressure.

Further, the reaction medium used in the method is an aqueous solution of acetonitrile, an aqueous solution of benzonitrile, an aqueous solution of acetone, an aqueous solution of ethanol, an aqueous solution of tert-butanol, an aqueous solution of 1,2-dichloroethane, and an aqueous solution of ethyl acetate. Aqueous solution, aqueous solution of tetrahydrofuran or aqueous solution of dimethyl sulfoxide, wherein the volume ratio of organic solvent to water is 1:(0.5-100), preferably 1:(1-10).

Further, the molar ratio of alkylaromatic compound, hydrosilane, oxidizing agent and iron catalyst is 1:(1～10):(1～10):(0.005～0.5), preferably 1:(3-6):( 1-3): (0.01-0.11), the weight ratio of the alkylaromatic compound to the reaction medium is 1: (5-1000). In the method, the reaction temperature is 20-180°C, preferably 25-80°C, and the reaction time is 0.5-60 hours, preferably 3-25h.

Beneficial effect

Compared with the prior art, the beneficial effects of the present invention are:

(1) The present invention provides a new method for the preparation of aromatic aldehydes, aromatic ketones and aromatic esters by iron-catalyzed benzylic oxidative carbonylation of side chains of alkyl aromatic hydrocarbons in an aqueous solution of an organic solvent. The advantage of being simple and easy to obtain; the oxidants and accelerators required by the method are widely sourced and environmentally friendly; the reaction selectivity is good and the yield is high; the functional group compatibility is good and the scope of application is wide; it is suitable for the post-oxidative carbonylation of complex molecules, This has important application value in the fields of medicine and biochemistry;

(2) In the synthetic method of aromatic aldehyde, aromatic ketone and aromatic ester provided by the invention, the source of substrate is extensive, stable and cheap, and method is simple and easy, and one-step method directly obtains aromatic aldehyde, aromatic ketone and aromatic ester, and in optimized reaction Under the conditions, the separation yield of the target product is as high as 95%, which is a general, efficient, economical and environmentally friendly method for synthesizing aromatic aldehydes, aromatic ketones and aromatic esters;

(3) The key that the method of the present invention can obtain ideal catalytic effect is that the organic catalytic system "aqueous solution of organic solvent-iron catalyst-oxidant-promoter" has been found. The organocatalytic combination ensures the in-situ formation of highly active catalytic species, ensuring the high efficiency of the reaction; while the reaction proceeds efficiently, it suppresses the problems of overoxidation and overreduction, ensuring high selectivity and functional group compatibility of the reaction Good and wide range of advantages.

detailed description

The present invention will be further described below in conjunction with specific embodiments.

In order to further explain the technical means and effects adopted by the present invention to achieve the intended invention purpose, the specific implementation methods, features and effects of the technical solutions proposed according to the present invention are described in detail below.

Example 1

Compound 1: Add ferrous acetylacetonate (0.025mmol), polymethylhydrogensiloxane (0.75mmol), potassium persulfate (0.25mmol), 1a (0.25mmol), acetonitrile (1mL), water to a 25mL reaction flask in sequence (1 mL), the reaction mixture was reacted at 80°C for 6h. After the reaction, add ammonia water (2 mL) to remove polymethylhydrogen siloxane, add 10 mL of saturated saline, and extract with ether (10 mL×3), combine the organic phases, evaporate the solvent under reduced pressure, and separate by column chromatography to obtain a yield of 80%. .

Example 2

Compound 2: Iron acetylacetonate (0.025mmol), polymethylhydrogensiloxane (0.75mmol), potassium persulfate (0.25mmol), 1b (0.25mmol), acetonitrile (1mL), water ( 1 mL), the reaction mixture was reacted at 80°C for 3h. After the reaction, add ammonia water (2 mL) to remove polymethylhydrogen siloxane, add 10 mL of saturated saline, and extract with ether (10 mL×3), combine the organic phases, evaporate the solvent under reduced pressure, and separate by column chromatography to obtain a yield of 80%. .

Example 3

Compound 3: Add ferrous acetylacetonate (0.025mmol), polymethylhydrogensiloxane (0.75mmol), potassium persulfate (0.25mmol), 1c (0.25mmol), acetonitrile (1mL), water to a 25mL reaction flask in sequence (1 mL), the reaction mixture was reacted at 80° C. for 3 h. After the reaction, add ammonia water (2 mL) to remove polymethylhydrogen siloxane, add 10 mL of saturated saline, and extract with ether (10 mL×3), combine the organic phases, evaporate the solvent under reduced pressure, and separate by column chromatography to obtain a yield of 80%. .

Example 4

Compound 4: Add ferrous acetylacetonate (0.025mmol), polymethylhydrogensiloxane (0.75mmol), potassium persulfate (0.25mmol), 1d (0.25mmol), acetonitrile (1mL), water to a 25mL reaction flask in sequence (1 mL), the reaction mixture was reacted at 80°C for 6h. After the reaction, add ammonia water (2 mL) to remove polymethylhydrogen siloxane, add 10 mL of saturated saline, and extract with ether (10 mL×3), combine the organic phases, evaporate the solvent under reduced pressure, and separate by column chromatography to obtain a yield of 87%. .

Example 5

Compound 5: Add ferrous acetylacetonate (0.025mmol), polymethylhydrogensiloxane (0.75mmol), potassium persulfate (0.25mmol), 1e (0.25mmol), acetonitrile (1mL), water to a 25mL reaction flask in sequence (1 mL), the reaction mixture was reacted at 80° C. for 3 h. After the reaction, add ammonia (2 mL) to remove polymethylhydrogen siloxane, add 10 mL of saturated saline, and extract with ether (10 mL×3), combine the organic phases, evaporate the solvent under reduced pressure, and separate by column chromatography to obtain a yield of 85%. .

Example 6

Compound 6: Add ferrous acetylacetonate (0.025mmol), 1,1,3,3-tetramethyldisiloxane (0.75mmol), potassium persulfate (0.25mmol), 1f (0.25mmol ), 1,2-dichloroethane (1 mL), water (1 mL), and the reaction mixture was reacted at 80° C. for 3 h. After the reaction, add ammonia (2 mL) to remove polymethylhydrogen siloxane, add 10 mL of saturated saline, and extract with ether (10 mL×3), combine the organic phases, evaporate the solvent under reduced pressure, and separate by column chromatography to obtain a yield of 70%. .

Example 7

Compound 7: Add ferrocene (0.025mmol), ferrous phthalocyanine (0.0025mmol), polymethylhydrogensiloxane (0.75mmol), potassium persulfate (0.75mmol), 1g (0.25mmol) to a 25mL reaction flask in sequence , acetonitrile (1 mL), water (1 mL), and the reaction mixture was reacted at 80° C. for 3 h. After the reaction, add ammonia (2 mL) to remove polymethylhydrogen siloxane, add 10 mL of saturated saline, and extract with ether (10 mL×3), combine the organic phases, distill off the solvent under reduced pressure and separate by column chromatography to obtain a yield of 78%. .

Example 8

Compound 8: Add ferrous acetylacetonate (0.025mmol), triethylsilane (0.75mmol), potassium persulfate (0.25mmol), 1h (0.25mmol), tert-butanol (1mL), water ( 1 mL), the reaction mixture was reacted at 80°C for 9h. After the reaction, add ammonia water (2mL) to remove polymethylhydrogensiloxane, add 10mL of saturated saline, and extract with ether (10mL×3), combine the organic phases, distill off the solvent under reduced pressure and separate by column chromatography to obtain a yield of 72% .

Example 9

Compound 9: Add ferrous trifluoromethanesulfonate (0.025mmol), ferrous phthalocyanine (0.0025mmol), polymethylhydrogensiloxane (0.75mmol), potassium persulfate (0.75mmol), 1i (0.25mmol), acetonitrile (1mL), water (1mL), and the reaction mixture was reacted at 80°C for 16h. After the reaction, add ammonia (2 mL) to remove polymethylhydrogen siloxane, add 10 mL of saturated saline, and extract with ether (10 mL×3), combine the organic phases, evaporate the solvent under reduced pressure, and separate by column chromatography to obtain a yield of 70%. .

Example 10

Compound 10: Iron iodide (0.025mmol), polymethylhydrogensiloxane (0.75mmol), potassium persulfate (0.25mmol), 1j (0.25mmol), acetonitrile (1mL), water ( 1 mL), the reaction mixture was reacted at 80°C for 3h. Add ammonia water (2mL) to remove polymethylhydrosiloxane at the end of the reaction, add saturated brine 10mL, and extract with ether (10mL×3), combine the organic phases, distill off the solvent under reduced pressure and separate by column chromatography to obtain a yield of 60% .

Example 11

Compound 11: Add ferrous acetylacetonate (0.025mmol), polymethylhydrogensiloxane (0.75mmol), potassium persulfate (0.25mmol), 1k (0.25mmol), acetonitrile (1mL), water to a 25mL reaction flask in sequence (1 mL), the reaction mixture was reacted at 80° C. for 3 h. After the reaction, add ammonia (2 mL) to remove polymethylhydrogen siloxane, add 10 mL of saturated saline, and extract with ether (10 mL×3), combine the organic phases, evaporate the solvent under reduced pressure, and separate by column chromatography to obtain a yield of 95%. .

Example 12

Compound 12: Add ferrocene (0.025mmol), ferrous phthalocyanine (0.0025mmol), polymethylhydrogensiloxane (0.75mmol), potassium persulfate (0.75mmol), 1L (0.25mmol) to a 25mL reaction flask in sequence , acetonitrile (1 mL), water (1 mL), and the reaction mixture was reacted at 80° C. for 6 h. After the reaction, add ammonia water (2 mL) to remove polymethylhydrogen siloxane, add 10 mL of saturated saline, and extract with ether (10 mL×3), combine the organic phases, evaporate the solvent under reduced pressure, and separate by column chromatography to obtain a yield of 92%. .

Example 13

Compound 13: Add ferrocene (0.025mmol), ferrous phthalocyanine (0.0025mmol), polymethylhydrosiloxane (0.75mmol), potassium persulfate (0.75mmol), 1m (0.25mmol) to a 25mL reaction flask in sequence , acetonitrile (1 mL), water (1 mL), and the reaction mixture was reacted at 80° C. for 9 h. After the reaction, add ammonia water (2 mL) to remove polymethylhydrogen siloxane, add 10 mL of saturated saline, and extract with ether (10 mL×3), combine the organic phases, evaporate the solvent under reduced pressure, and separate by column chromatography to obtain a yield of 80%. .

Example 14

Compound 14: Add iron 1,3-diphenylpropanedione (0.025mmol), ferrous phthalocyanine (0.0025mmol), triethoxysilane (1.5mmol), sodium persulfate (0.75mmol) to a 25mL reaction flask in sequence ), 1n (0.25mmol), acetonitrile (1mL), water (1mL), and the reaction mixture was reacted at 80°C for 17h. Add ammonia water (2mL) to remove polymethylhydrosiloxane at the end of the reaction, add saturated brine 10mL, and extract with ether (10mL×3), combine the organic phases, distill off the solvent under reduced pressure and separate by column chromatography to obtain a yield of 60% .

Example 15

Compound 15: Add ferrocene (0.025mmol), ferrous phthalocyanine (0.0025mmol), polymethylhydrogensiloxane (0.75mmol), potassium persulfate (0.75mmol), 1o (0.25mmol) to a 25mL reaction flask in sequence , acetonitrile (1 mL), water (1 mL), and the reaction mixture was reacted at 80° C. for 3 h. After the reaction, add ammonia (2 mL) to remove polymethylhydrogen siloxane, add 10 mL of saturated saline, and extract with ether (10 mL×3), combine the organic phases, evaporate the solvent under reduced pressure, and separate by column chromatography to obtain a yield of 95%. .

Example 16

Compound 16: Add ferrous sulfate (0.025mmol), ferrous phthalocyanine (0.0025mmol)-phenylsilane (0.75mmol), potassium hydrogen peroxosulfate complex salt (0.75mmol), 1p (0.25mmol ), acetonitrile (1 mL), water (1 mL), and the reaction mixture was reacted at 80° C. for 9 h. Add ammonia water (2mL) to remove polymethylhydrosiloxane at the end of the reaction, add saturated brine 10mL, and extract with ether (10mL×3), combine the organic phases, distill off the solvent under reduced pressure and separate by column chromatography to obtain a yield of 60% .

Example 17

Compound 17: Add ferrocene (0.025mmol), ferrous phthalocyanine (0.0025mmol), diphenylchlorosilane (1.5mmol), potassium persulfate (0.75mmol), 1q (0.25mmol), acetonitrile to a 25mL reaction flask in sequence (1 mL), water (1 mL), and the reaction mixture was reacted at 80° C. for 6 h. After the reaction, add ammonia water (2mL) to remove polymethylhydrogensiloxane, add 10mL of saturated saline, and extract with ether (10mL×3), combine the organic phases, distill off the solvent under reduced pressure and separate by column chromatography to obtain a yield of 72% .

Example 18

Compound 18: Add ferric oxide (0.025mmol), ferrous phthalocyanine (0.0025mmol), polymethylhydrogensiloxane (0.75mmol), oxygen (1atm), 1r (0.25mmol), acetonitrile to a 25mL reaction flask in sequence (1 mL), water (1 mL), and the reaction mixture was reacted at 80° C. for 12 h. Add ammonia water (2mL) to remove polymethylhydrogensiloxane at the end of the reaction, add saturated brine 10mL, and extract with ether (10mL×3), combine the organic phases, distill off the solvent under reduced pressure and separate by column chromatography to obtain a yield of 50% .

Example 19

Compound 19: Add ferrocene (0.025mmol), ferrous phthalocyanine (0.0025mmol), polymethylhydrogensiloxane (0.75mmol), potassium persulfate (0.75mmol), 1s (0.25mmol) to a 25mL reaction flask in sequence , acetonitrile (1 mL), water (1 mL), and the reaction mixture was reacted at 80° C. for 6 h. After the reaction, add ammonia water (2 mL) to remove polymethylhydrogen siloxane, add 10 mL of saturated saline, and extract with ether (10 mL×3), combine the organic phases, evaporate the solvent under reduced pressure, and separate by column chromatography to obtain a yield of 92%. .

Example 20

Compound 20: Add ferrous acetylacetonate (0.025mmol), polymethylhydrogensiloxane (0.75mmol), potassium persulfate (0.25mmol), 1t (0.25mmol), acetonitrile (1mL), water to a 25mL reaction flask in sequence (1 mL), the reaction mixture was reacted at 80°C for 8h. After the reaction, add ammonia (2 mL) to remove polymethylhydrogen siloxane, add 10 mL of saturated saline, and extract with ether (10 mL×3), combine the organic phases, evaporate the solvent under reduced pressure, and separate by column chromatography to obtain a yield of 95%. .

Example 21

Compound 21: Add iron acetylacetonate (0.025mmol), ferrous phthalocyanine (0.0025mmol), isopropoxyphenylsilane (0.75mmol), hydrogen peroxide (0.75mmol), 1u (0.25mmol), acetonitrile to a 25mL reaction flask in sequence (1 mL), water (1 mL), and the reaction mixture was reacted at 80° C. for 3 h. Add ammonia water (2mL) to remove polymethylhydrogensiloxane at the end of the reaction, add saturated brine 10mL, and extract with ether (10mL×3), combine the organic phases, distill off the solvent under reduced pressure and separate by column chromatography to obtain a yield of 65% .

Example 22

Compound 22: Ferrocene (0.025mmol), polymethylhydrogensiloxane (0.75mmol), potassium persulfate (0.25mmol), 1v (0.25mmol), acetonitrile (1mL), water ( 1 mL), the reaction mixture was reacted at 50°C for 3h. After the reaction, add ammonia water (2 mL) to remove polymethylhydrogen siloxane, add 10 mL of saturated saline, and extract with ether (10 mL×3), combine the organic phases, evaporate the solvent under reduced pressure, and separate by column chromatography to obtain a yield of 67%. .

Example 23

Compound 23: Add ferrous benzoylacetonate (0.025mmol), ferrous phthalocyanine (0.0025mmol), polymethylhydrogensiloxane (0.75mmol), peracetic acid (0.75mmol), 1w( 0.25mmol), benzonitrile (1mL), water (1mL), and the reaction mixture was reacted at 80°C for 12h. Add ammonia water (2mL) to remove polymethylhydrogensiloxane at the end of the reaction, add saturated brine 10mL, and extract with ether (10mL×3), combine the organic phases, distill off the solvent under reduced pressure and separate by column chromatography to obtain a yield of 65% .

Example 24

Compound 24: Add ferrous chloride (0.025mmol), polymethylhydrogensiloxane (0.75mmol), potassium persulfate (0.25mmol), 1x (0.25mmol), acetonitrile (1mL), water to a 25mL reaction flask in sequence (1 mL), the reaction mixture was reacted at 80° C. for 18 h. Add ammonia water (2mL) to remove polymethylhydrosiloxane at the end of the reaction, add 10mL of saturated saline, and extract with ether (10mL×3), combine the organic phases, distill off the solvent under reduced pressure and separate by column chromatography to obtain a yield of 68% .

Example 25

Compound 25: Add ferrous 2,2,6,6-tetramethyl-3,5-heptanedionate (0.0025mmol), polymethylhydrogensiloxane (0.75mmol), and potassium persulfate to a 25mL reaction flask in sequence (0.25mmol), 1y (0.25mmol), acetonitrile (1mL), water (1mL), and the reaction mixture was reacted at 25°C for 3h. After the reaction, add ammonia (2 mL) to remove polymethylhydrogen siloxane, add 10 mL of saturated saline, and extract with ether (10 mL×3), combine the organic phases, evaporate the solvent under reduced pressure, and separate by column chromatography to obtain a yield of 74%. .

Example 26

Compound 26: Add ferric ferricyanide (0.05mmol), ferrous phthalocyanine (0.0025mmol), polymethylhydrosiloxane (0.75mmol), potassium persulfate (0.75mmol), 1z (0.25mmol ), dimethylsulfoxide (0.2mL), water (2mL), and the reaction mixture was reacted at 80°C for 6h. Add ammonia water (2mL) to remove polymethylhydrosiloxane at the end of the reaction, add 10mL of saturated saline, and extract with ether (10mL×3), combine the organic phases, distill off the solvent under reduced pressure and separate by column chromatography to obtain a yield of 68% .

Example 27

Compound 27: Add ferrous acetylacetonate (0.025mmol), polymethylhydrogensiloxane (0.75mmol), potassium persulfate (0.25mmol), 1aa (0.25mmol), acetonitrile (1mL), water to a 25mL reaction flask in sequence (1 mL), the reaction mixture was reacted at 80°C for 6h. After the reaction, add ammonia water (2 mL) to remove polymethylhydrogen siloxane, add 10 mL of saturated saline, and extract with ether (10 mL×3), combine the organic phases, evaporate the solvent under reduced pressure, and separate by column chromatography to obtain a yield of 87%. .

Example 28

Compound 28: Add ferrous acetylacetonate (0.025mmol), tris(trimethylsilyl)silane (0.75mmol), potassium persulfate (0.25mmol), 1ab (0.25mmol), tetrahydrofuran (1mL), water to a 25mL reaction flask in sequence (1 mL), the reaction mixture was reacted at 80°C for 8h. After the reaction, add ammonia water (2 mL) to remove polymethylhydrogen siloxane, add 10 mL of saturated saline, and extract with ether (10 mL×3), combine the organic phases, evaporate the solvent under reduced pressure, and separate by column chromatography to obtain a yield of 91%. .

Example 29

Compound 29: Ferric bromide (0.025mmol), dimethylmethylhydrogen (siloxane and polysiloxane) (0.75mmol), potassium persulfate (0.25mmol), 1ac (0.25mmol ), ethyl acetate (1 mL), water (1 mL), and the reaction mixture was reacted at 80° C. for 12 h. After the reaction, add ammonia (2 mL) to remove polymethylhydrogen siloxane, add 10 mL of saturated saline, and extract with ether (10 mL×3), combine the organic phases, evaporate the solvent under reduced pressure, and separate by column chromatography to obtain a yield of 70%. .

Example 30

Compound 30: Add ferrous acetylacetonate (0.025mmol), dimethylethylsilane (1.5mmol), potassium persulfate (0.25mmol), 1ad (0.25mmol), acetonitrile (1mL), water ( 1 mL), the reaction mixture was reacted at 80°C for 5h. Add ammonia water (2mL) to remove polymethylhydrogensiloxane at the end of the reaction, add saturated brine 10mL, and extract with ether (10mL×3), combine the organic phases, distill off the solvent under reduced pressure and separate by column chromatography to obtain a yield of 50% .

Example 31

Compound 31: Add ferrous bromide (0.025mmol), tetrakis(dimethylsiloxy)silane (0.75mmol), potassium persulfate (0.25mmol), 1ae (0.25mmol), tert-butanol to a 25mL reaction flask in sequence (1 mL), water (1 mL), and the reaction mixture was reacted at 80° C. for 20 h. After the reaction, add ammonia water (2 mL) to remove polymethylhydrogen siloxane, add 10 mL of saturated saline, and extract with ether (10 mL×3), combine the organic phases, evaporate the solvent under reduced pressure, and separate by column chromatography to obtain a yield of 40%. .

Example 32

Compound 32: Add ferrous acetylacetonate (0.025mmol), polymethylhydrogensiloxane (0.75mmol), potassium persulfate (0.25mmol), 1af (0.25mmol), acetonitrile (1mL), water to a 25mL reaction flask in sequence (1 mL), the reaction mixture was reacted at 80° C. for 5 h. Add ammonia water (2mL) to remove polymethylhydrosiloxane at the end of the reaction, add saturated brine 10mL, and extract with ether (10mL×3), combine the organic phases, distill off the solvent under reduced pressure and separate by column chromatography to obtain a yield of 60% .

Example 33

Compound 31: Add ferrous acetylacetonate (0.025mmol), 1,1,2,2-tetraphenyldisilane (0.75mmol), potassium persulfate (0.25mmol), 1ag (0.25mmol), Acetonitrile (1 mL), water (1 mL), and the reaction mixture was reacted at 80° C. for 25 h. Add ammonia water (2mL) to remove polymethylhydrogensiloxane at the end of the reaction, add saturated brine 10mL, and extract with ether (10mL×3), combine the organic phases, distill off the solvent under reduced pressure and separate by column chromatography to obtain a yield of 50% .

Example 34

Compound 31: Add ferrous acetylacetonate (0.025mmol), polymethylhydrogensiloxane (0.75mmol), potassium persulfate (0.25mmol), 1ah (0.25mmol), acetonitrile (1mL), water to a 25mL reaction flask in sequence (1 mL), the reaction mixture was reacted at 80° C. for 12 h. Add ammonia water (2mL) to remove polymethylhydrogensiloxane at the end of the reaction, add 10mL of saturated saline, and extract with ether (10mL×3), combine the organic phases, distill off the solvent under reduced pressure and separate by column chromatography to obtain a yield of 73% .

The experimental results corresponding to the synthetic methods of specific aromatic aldehydes, aromatic ketones and aromatic esters in Examples 1 to 34 are listed in Table 1:

Table 1 Synthesis of aryl aldehydes, aryl ketones and aryl esters by iron-catalyzed oxidation of alkylaromatic side chains ^[a]

[a] See the examples for the reaction conditions; [b] column separation yield.

The above description is only a preferred embodiment of the present invention, and does not limit the present invention in any form. Although the present invention has been disclosed as above with preferred embodiments, it is not intended to limit the present invention. Each of the present invention All kinds of iron catalysts can react with hydrogen silicon reagents to form highly active catalytic active substances, thus ensuring the effective progress of the reaction; hydrogen silicon reagents make the necessary promoters for the effective reaction to use the reducibility of silicon hydrogen, theoretically The various hydrosilanes given have certain reducibility, and should be able to achieve similar effects; the oxidizing agent is the key substance that plays an oxidation role in the reaction process, and in theory, various oxidizing agents with the function of oxygen supply can promote the reaction Occurrence; the chemical bond of the alkyl aromatic compound is the carbon-hydrogen bond on the benzylic carbon, the change of the substituent on the aromatic ring and the change of the alkyl itself affect the electron cloud density of the aromatic ring and the space of the reaction site Steric hindrance, that is, the modification of substituents only affects the reaction to a certain extent, and does not play a decisive role in the reaction itself. It is not difficult for any person familiar with the art to understand that without departing from the scope of the technical solutions of the present invention, when changes or modifications can be made to obtain corresponding embodiments, for example, the substituents described can be replaced and changed within the scope of the present invention Or modification, all can realize the method of the present invention. However, any modifications, modifications, or equivalent and equivalent changes made to the above embodiments according to the present invention shall still fall within the scope of the technical solution of the present invention without departing from the purpose of the technical solution of the present invention.

Claims (10)

1. A method for the synthesis of aromatic aldehydes, aryl ketones and aryl esters by iron-catalyzed oxidation of alkyl aromatic compounds, characterized in that: in the method, iron is used as a catalyst, and under the joint action of promotor and oxidizing agent, hydrogen silane is oxidized Metered alkylaromatic compounds, preparation of aryl aldehydes, aryl ketones and aryl esters. The general reaction formula is as follows: In the formula: The aryl represented by Ar is substituted or unsubstituted phenyl, biphenyl, naphthyl, anthracenyl, phenanthrenyl or pyrenyl; the heteroaryl represented by Ar is a five to thirteen-membered ring containing N, O or S R represents hydrogen, aryl, heteroaryl, alkyl, alkoxy or aryloxy. 2. the method for a kind of iron catalytic oxidation alkyl aromatic compound according to claim 1 synthetic aromatic aldehyde, aryl ketone and aryl ester, it is characterized in that: the heteroaryl group that described Ar represents is substituted or unsubstituted furan benzofuryl, thienyl, pyrrolyl, indolyl, pyridyl, isoxazolyl, pyrazolyl, imidazolyl, oxazolyl or thiazolyl. 3. the method for a kind of iron catalytic oxidation alkyl aromatic compound according to claim 1 to synthesize aromatic aldehyde, aryl ketone and aryl ester, it is characterized in that: the aryl group represented by R is substituted or unsubstituted phenyl, bis Phenyl, naphthyl, anthracenyl, phenanthrenyl or pyrenyl; heteroaryl represented by R is substituted or unsubstituted furyl, benzofuryl, thienyl, pyrrolyl, indolyl, pyridyl, isoxa Azolyl, pyrazolyl, imidazolyl, oxazolyl or thiazolyl; the alkyl group represented by R is C1-C20 straight chain or branched chain alkyl; the alkoxy group represented by R is C1-C20 straight chain or branched chain The alkoxy group represented by R; the aryloxy group represented by R is substituted or unsubstituted phenoxy, biphenyloxy, naphthyloxy, anthracenyloxy, phenanthrenyloxy, pyreneoxy, furanyloxy, benzofuryloxy thienyloxy, pyrroleoxy, indoxyl, pyridyloxy, isoxazolyloxy, pyrazolyloxy, imidazolyloxy, oxazolyloxy or thiazolyloxy. 4. the method for a kind of iron catalytic oxidation alkyl aromatic compound according to claim 1 synthetic aromatic aldehyde, aryl ketone and aryl ester, it is characterized in that: when the aryl group represented by described Ar or R is a substituted aryl group, The substituents on it are monosubstituted or multi-substituted hydrogen on the aromatic ring, and the substituents are arbitrarily selected from hydrogen, C1~C20 straight chain or branched chain hydrocarbon groups, C1~C30 straight chain or branched chain alkoxy groups, C1-C30 linear or branched alkylmercapto, aryl, heteroaryl, hydroxyl, carboxyl, -B(OH) ₂ , fluorine, chlorine, bromine, iodine, alkanoyloxy or aroyloxy. 5. the method for a kind of iron catalytic oxidation alkyl aromatic compound according to claim 1 synthetic aromatic aldehyde, aryl ketone and aryl ester, it is characterized in that: the heteroaryl represented by described Ar or R is pyrrolyl, imidazole In the case of radical, indolyl and pyrazolyl, the substituents on the nitrogen atom are arbitrarily selected from hydrogen, C1-C12 linear or branched alkyl, C3-C12 cycloalkyl, aryl, p-toluenesulfonyl , acetyl, benzoyl or tert-butoxyyl. 6. according to the method for a kind of iron catalytic oxidation alkyl aromatic compound described in any one of claim 1-5 synthetic aromatic aldehyde, aromatic ketone and aromatic ester, it is characterized in that: described iron catalyst is selected from iron powder, three Ferrous fluoromethanesulfonate, ferric trifluoromethanesulfonate, ferrous chloride, ferrous acetylacetonate, ferrous acetylacetonate, ferrous 2,2,6,6-tetramethyl-3,5-heptanedionate, 2,2,6,6-tetramethyl-3,5-heptanedionate iron, 1,3-diphenylpropanedione ferrous, 1,3-diphenylpropanedione iron, benzoylacetone Ferrous, ferric benzoylacetonate, ferric ferricyanide, ferric ferricyanide, ferrous acetate, ferrous sulfate, ammonium ferrous sulfate, ferric sulfate, ferrous phthalocyanine, ferrocene, ferrous fluoride, Ferric fluoride, ferrous bromide, ferric bromide, ferrous iodide, ferric iodide, ferric chloride, ferric oxide, or ferric oxide. 7. according to the method for a kind of iron catalysis oxidation alkyl aromatic compound described in any one of claim 1-5 synthetic aromatic aldehyde, aromatic ketone and aromatic ester, it is characterized in that: described hydrosilane is triethylsilane , triethoxysilane, polymethylhydrogensiloxane, triisopropylsilane, dimethylphenylsilane, monophenylsilane, diphenylsilane, triphenylsilane or 1,1,3,3 - Tetramethyldisiloxane, dimethylethoxysilane, dimethylethylsilane, benzyldimethylsilane, diethylsilane, dichlorophenylsilane, dimethylmonochlorosilane, di Isopropyl chlorosilane, chloromethyl (dimethyl) silane, di-tert-butyl chlorosilane, diphenyl chlorosilane, ethyl dichlorosilane, di-tert-butyl silane, methyl diphenyl silane, methyl Dichlorosilane, tert-butyldimethylsilane, 1,4-bis(dimethylsilyl)benzene, isopropoxyphenylsilane, methyldiethoxysilane, dimethoxy(methylsilyl) base) silane, dimethylmethylhydrogen (siloxane and polysiloxane), 1,1,3,3-tetraisopropyldisiloxane, tris(trimethylsilyl)silane, methylphenyl Silicone oil, pentamethyldisiloxane, tetrakis(dimethylsilyl)silane, 1,3-bis(3,3,3-trifluoropropyl)-1,1,3,3-tetramethyldisilazane oxyoxane, tetrakis(dimethylsiloxy)silane, phenyltris(dimethylsiloxy)silane or 1,1,2,2-tetraphenyldisilane. 8. according to the method for a kind of iron catalytic oxidation alkyl aromatic compound described in any one of claim 1-5 synthetic aromatic aldehyde, aromatic ketone and aromatic ester, it is characterized in that: described oxygenant is oxygen, hydrogen peroxide, peroxide Oxyacetic acid, potassium peroxodisulfate compound salt, potassium peroxosulfate, ammonium peroxosulfate or sodium peroxosulfate; when oxygen is the oxidizing agent, the gas pressure is 0.5-2.0 atmospheres. 9. according to the method for a kind of iron catalytic oxidation alkyl aromatic compound described in any one of claim 1-5 synthetic aromatic aldehyde, aromatic ketone and aromatic ester, it is characterized in that: the reaction medium that adopts in the described method is acetonitrile aqueous solution of benzonitrile, acetone, ethanol, tert-butanol, 1,2-dichloroethane, ethyl acetate, tetrahydrofuran or dimethyl sulfoxide, Wherein the volume ratio of organic solvent and water is 1:(0.5～100). 10. according to the method for a kind of iron catalytic oxidation alkyl aromatic compound described in any one of claim 1-5 synthetic aromatic aldehyde, aryl ketone and aryl ester, it is characterized in that: described alkyl aromatic compound, hydrosilane , the mol ratio of oxidizing agent and iron catalyst is 1:(1～10):(1～10):(0.005～0.5), the weight ratio of alkyl aromatic compound and reaction medium is 1:(5～1000); In the above method, the reaction temperature is 20-180° C., and the reaction time is 0.5-60 hours.