RU2245885C1 - Method of jointly preparing 2-alkylidenemagnesiumcyclopentanes and 2-alkyl-3-methylidenemagnesiumcyclopentanes - Google Patents

Abstract

FIELD: organic synthesis.

SUBSTANCE: invention relates to preparation of novel organomagnesium compounds, which consists in reaction of alkylallenes with diethylmagnesium in presence of zirconacene dichloride as catalyst used in amount 0.2 to 0.6 mmole based on alkylallene in diethyl ether medium under argon atmosphere, reaction time being 8-12 h.

EFFECT: extended assortment of organomagnesium compounds, which can find use as components of catalytic systems in processes of oligo- and polymerization of olefin, diene, and acetylene hydrocarbons as well as in delicate organic and organometallic syntheses.

1 tbl, 8 ex

Description

The present invention relates to methods for producing new organomagnesium compounds (MOS), specifically to a joint method for producing 2-alkylidene magnesium cyclopentanes (1) and 2-alkyl-3-methylidene magnesium cyclopentanes (2) of the general formula:

, где R=н-С₅Н₁₁, H-C₇H₁₅

where R = nC ₅ H ₁₁ , HC ₇ H ₁₅

The proposed compounds can find application as a component of catalytic systems in the processes of oligo- and polymerization of olefin, diene and acetylene hydrocarbons, as well as in fine organic and organometallic syntheses.

A known method ([1] U. M. Dzhemilev, PM Sultanov, R. G. Gaimaldinov, G. Tolstikov, Izvestiya AN SSSR, 1991, No. 6, p. 1388) for joint production of five-membered and seven-membered cyclic MOS, namely: 2-phenylmagnesium cyclopentane (3) and 2,4-diphenylmagnesium cycloheptane (4) with a yield of 70 and 5%, respectively, by the reaction of unsubstituted magnesium cyclopentane with styrene taken in a 1: 1 ratio in the presence of 2-3 mol% Cp ₂ ZrCl ₂ in a THF solution at 25 ° C (15 h) according to the scheme:

The known method does not allow to obtain MOS (1) and (2).

A known method ([2] U. M. Dzhemilev, PM Sultanov, R. G. Gaimaldinov, PP Muslushev, S. I. Lomakin, G. A. Tolstikov, Izvestia AN, 1992, No. 4, p. 980) for the production of magnesium cyclopentanes, and namely: 2-phenyl-2-ethyl (butyl) magnesium cyclopentanes (5) and 2,4-diphenyl magnesium cyclopentanes (6), the interaction of diethyl (butyl) magnesium with styrene in the presence of 3-5 mol. % Cp ₂ ZrCl ₂ at 20-25 ° С, in THF medium: ether = 1: 1 for 7 hours according to the scheme:

The known method does not allow to obtain MOS (1) and (2).

Thus, in the literature there is no information on the synthesis of 2-alkylidene magnesium cyclopentanes (1) and 2-alkyl-3-methylidene magnesium cyclopentanes (2).

A new method is proposed for the synthesis of 2-alkylidene magnesium cyclopentanes (1) and 2-alkyl-3-methylidene magnesium cyclopentanes (2).

The essence of the method consists in the interaction of alkyl allenes of the general formula R- = • =, where R = n — C ₅ H ₁₁ , n — C ₇ H ₁₅ , with diethyl magnesium (Et ₂ Mg) taken in the ratio R- = • =: Et ₂ Mg = 10: (15-25), preferably 10:20 mmol, in the presence of a catalyst of zirconacene dichloride (Cp ₂ ZrCl ₂ ) in an amount of 0.2-0.6 mmol, preferably 0.4 mmol in an argon atmosphere at 0 ° C and atmospheric pressure in diethyl ether. The reaction time is 8-12 hours, preferably 10 hours. The total yield of 2-alkylidene magnesium cyclopentanes (1) and 2-alkyl-3-methylidene magnesium cyclopentanes (2) is 72-90%, ratio (1) :( 2) = 2: 1. The reaction proceeds according to the scheme:

R = n-C ₅ H ₁₁ , n-C ₇ H ₁₅

2-alkylidene magnesium cyclopentanes (1) and 2-alkyl-3-methylidene magnesium cyclopentanes (2) are formed only with the participation of Et ₂ Mg and the zirconium catalyst Cp ₂ ZrCl ₂ . In the presence of other magnesium compounds (e.g., EtMgBr, Bu ₂ Mg) or another catalyst (e.g., Cp ₂ TiCl ₂ , Zr (acac) ₄ , Pd (acac) ₂ , Ni (acac) ₂ , NiCl ₂ , FeCl ₂ ) target products (1) and (2) are not formed. Carrying out this reaction in the presence of a zirconium catalyst Cp ₂ ZrCl ₂ more than 0.6 mmol does not lead to a significant increase in the target products. The use of a catalyst of less than 0.2 mmol decreases the yield of MOS (1) and (2), which is possibly associated with a decrease in catalytically active sites in the reaction mass. The synthesis was carried out at a temperature of ~ 0 ° C with stirring for 10 hours.

A change in the ratio of the starting reagents in the direction of increasing Et ₂ Mg relative to the starting alkyl allene does not increase the yield of the target products (1) and (2).

Significant differences of the proposed method:

1. In the proposed method, alkyl allenes (R- = • =) are used as starting unsaturated compounds, which determine the formation of 2-alkylidene magnesium cyclopentanes (1) and 2-alkyl-3-methylidene magnesium cyclopentanes (2). In the known method, styrene is used as the starting unsaturated compound, which promotes the formation of 2-phenyl-2-ethyl (butyl) magnesium cyclopentanes (5) and 2,4-diphenyl magnesium cyclopentanes (6).

The proposed method has the following advantages:

1. The method allows to obtain with high selectivity 2-alkylidene magnesium cyclopentanes (1) and 2-alkyl-3-methylidene magnesium cyclopentanes (2), the synthesis of which is not described in the literature.

The method is illustrated by the following examples:

Example 1. In a 50 ml glass reactor mounted on a magnetic stirrer in an argon atmosphere, 20 mmol of a solution of Et ₂ Mg in diethyl ether was placed, cooled to 0 ° C and 10 mmol of n-pentylallene, 0.4 mmol of Cp ₂ ZrCl _{2 were} added and stirred within 10 hours.

Get 2-hexylidene magnesium cyclopentane (1) and 2-pentyl-3-methylidene magnesium cyclopentane (2) with a total yield of 85% and the ratio (1) :( 2) ~ 2: 1. The total yield of the target products (1) and (2) was determined by the hydrolysis products. Hydrolysis of the obtained MOC of 2-alkylidene magnesium cyclopentanes (1) and 2-alkyl-3-methylidene magnesium cyclopentanes (2) produces decen-4 (7) and 2-ethylloctene-1 (8), identified by ¹³ C NMR, as well as by comparison with the known samples.

¹³ C NMR spectrum (δ, ppm, CDCl ₃ , TMC) decene-4 (7): 13.77 (C ¹ ), 14.06 (C ¹⁰ ), 22.66 (C ² ), 22.82 (C ⁹ ), 29.30 ( C ⁷ ), 31.0 (C ³ ), 31.62 (C ⁸ ), 32.00 (C ⁶ ), 130.21 (C ⁵ ), 130.82 (C ⁴ ).

¹³ C NMR spectrum (δ, ppm, CDCl ₃ , TMS) 2-ethyl-octene-1 (8): 12.71 (C ¹⁰ ), 14.06 (C ⁸ ), 22.81 (C ⁷ ), 27.21 (C ⁴ ), 29.75 (C ⁵ ), 31.43 (C ⁹ ), 31.96 (C ⁶ ), 36.02 (C ³ ), 107.82 (C ¹ ), 151.82 (C ² ).

During deuterolysis of MOS (1) and (2), 1,4-deuterodecene-4 (9) and 2 (2’-deuteroethyl) -3-deuterooctene-1 (10) were obtained, respectively

¹³ C NMR spectrum (δ, ppm, cdcl ₃ ), TMS) 1,4-dideuterodecene-4 (9): 13.47 (C ¹ , J = 19.05 Hz), 14.06 (C ¹⁰ ), 22.66 (C ² ), 22.82 (С ⁹ ), 29.30 (С ⁷ ), 31.00 (С ³ ), 31.62 (С ⁸ ), 32.00 (С ⁶ ), 130.21 (С ⁵ ), 130.82 (С ⁴ ).

¹³ C NMR spectrum (δ, ppm, CDCl ₃ , TMS) 2 (2'-deuteroethyl) -3-deuteroctene-1 (10): 12.41 (C ¹⁰ , J = 19.05 Hz), 14.06 (C ⁸ ) , 22.81 (C ⁷ ), 27.21 (C ⁴ ), 29.75 (C ⁵ ), 31.43 (C ⁹ ), 31.96 (C ⁶ ), 35.70 (C ³ , J = 19.05 Hz), 107.82 (C ¹ ), 151.82 ( C ² ).

Other examples confirming the method are given in table 1.

Table 1 №№

Исходный терминальный аллен, R-CH=C=CH₂

The original terminal allen, R-CH = C = CH ₂ Ratio: Et ₂ Mg: Cp ₂ ZrCl ₂ , mmol Total reaction time, hour The total yield of target products (1) and (2),% 1. ns₅N_elevenCH = C = CH₂
1- (n-pentylalkylene) 10: 20: 0.4 10 85 2. - 10: 25: 0.4 10 87 3. - 10: 15: 0.4 10 77 4. - 10: 25: 0.6 10 90 5. - 10: 25: 0.2 10 72 6. - 10: 25: 0.4 12 88 7. - 10: 25: 0.4 8 79 8. nc₇H_fifteenCH = C = CH₂
1- (n-heptylallen) 10: 25: 0.4 10 83

The reaction was carried out with stirring at a temperature of 0 ° C.

Claims (1)

A method for the joint production of 2-alkylidene magnesium cyclopentanes and 2-alkyl-3-methylidene magnesium cyclopentanes of the formula (1) and (2):

where R represents n-C ₅ H ₁₁ n-C ₇ H _15, consisting in the interaction of alkyl allenes of the formula R- = · =, where R is nC ₅ H ₁₁ , nC ₇ H ₁₅ , with diethyl magnesium in the presence of a zirconium catalyst Cp ₂ ZrCl ₂ in an amount of 0.2-0.6 mmol in the ratio R- = · =: Et ₂ Mg = 10: (15-25) mmol, and the reaction is carried out in diethyl ether in an argon atmosphere for 8-12 hours