RU2423370C2 - Method for combined synthesis of 1-ethyl-2-alkylidenealuminacyclopentanes and 1-ethyl-2-methylene-3-alkylaluminacyclopentanes - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to a method for combined synthesis of 1-ethyl-2-alkylidenealuminacyclopentanes (1) and 1-ethyl-2-methylene-3-alkylaluminacyclopentanes (2) of general formula:

, where R=n-C₄H₉, n-C₆H₁₃, n-C₈H₁₇. The method involves reaction of 1,2-alkadienes with organoaluminium compounds in the presence of a zirconocene dichloride (Cp₂ZrCl₂) catalyst at room temperature. The organoaluminium compound used is ethylaluminium dichloride (EtAlCl₂). The reaction takes place in the presence of Mg powder in molar ratio R-CH=C=CH₂:EtAlCl₂:Mg:Cp₂ZrCl₂=10:(10-20):(10-14):(0.6-1.0) in an ethylene atmosphere in a tetrahydrofuran (THF) solution for 6-10 hours.

EFFECT: invention enables to obtain 1-ethyl-2-alkylidenealuminacyclopentanes (1) and 1-ethyl-2-methylene-3-alkylaluminacyclopentanes (2) without using initial reagents which are self-inflammable in air.

1 ex, 1 tbl

Description

The present invention relates to the field of organoaluminum synthesis, specifically, to a method for the joint production of 1-ethyl-2-alkylidenealuminacyclopentanes (1) and 1-ethyl-2-methylene-3-alkylaluminium cyclopentanes (2) of the general formula:

, где R=н-C₄H₉, н-C₆H₁₃, н-C₈H₁₇

where R = n-C ₄ H ₉ , n-C ₆ H ₁₃ , n-C ₈ H ₁₇

These compounds can be used as components 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.

The known method ([1]. A. G. Ibrahimov, L. O. Khafizova, G. N. Gilfanova, U. M. Dzhemilev. Synthesis and transformation of metal cycles. The interaction of allens with EtAlCl ₂ and Et ₂ AlCl, catalyzed by complexes of Ti and Zr. Izv. AN SSSR. Ser.chem., 2002, No. 12, 2095-2100) for the joint production of a mixture of cyclic organoaluminum compounds (AOC) consisting of 1-ethyl-2-methylene-3-alkylaluminium cyclopropanes (3), 1- ethyl-2-alkylidenealuminacyclopropanes (4) and 1-ethyl-2,5-dialkylidenealuminacyclopentanes (5) in the ratio (3) :( 4) :( 5) ~ 6: 1: 2 with a total yield of ~ 80%, reaction 1, 2-dienes with ethyl aluminum dichloride (EtAl Cl ₂ ) in the presence of Mg and a Cp ₂ TiCl ₂ catalyst at room temperature for 8-12 hours. The reaction proceeds according to the scheme:

The cyclic AOC of 1-ethyl-2-alkylidenealuminacyclopentanes (1) and 1-ethyl-2-methylene-3-alkylaluminium cyclopentanes (2) cannot be obtained in a known manner.

The known method ([2]. L.O. Khafizova, A.G. Ibrahimov, G.N. Gilfanova, L.M. Khalilov, U.M. Dzhemilev. Synthesis and transformation of metalcycles. Catalyzed Cp ₂ ZrCl ₂ cycloalumination of substituted allens using El ₃ Al. Izv. AN SSSR. Ser. chem., 2001, No. 11, 2089-2093) to obtain a mixture of unsaturated cyclic AOS consisting of 1-ethyl-2-alkylidenealuminacyclopentanes (1) and 1-ethyl-2- methylene-3-alkylaluminium cyclopentanes (2) in the ratio (1) :( 2) ~ (6-7): 1, the interaction of 1,2-alkadiene (R-CH = C = CH ₂ ) with an excess of triethylaluminum (AlEt ₃ ) in tsirkonatsendihlorida presence of a catalyst (Cp ₂ ZrCl ₂₎ in hex are not taken in the molar ratio of R-CH = C = _CH2: AlEt _3: Cp ₂ ZrCl ₂ = 10: 13: 0.5 at a temperature of 20 ° C for 4 hours 85-95% overall yield according to the scheme:

The known method for producing cyclic AOS (1, 2) involves the use of extremely pyrophoric (self-igniting in air) AlEt ₃ as a starting reagent.

A new method is proposed for the joint production of 1-ethyl-2-alkylidenealuminacyclopentanes (1) and 1-ethyl-2-methylene-3-alkylaluminium cyclopentanes (2).

The essence of the method consists in the interaction of 1,2-dienes of the general formula R-CH = C = CH ₂ , where R = alkyl, for example n-C ₄ H ₉ , n-C ₆ H ₁₃ , n-C ₈ H ₁₇ , with ethyl aluminum dichloride (EtAlCl ₂ ) in the presence of magnesium (Mg, powder) and a Cp ₂ ZrCl ₂ catalyst taken in the molar ratio R-CH = C = CH ₂ : EtAlCl ₂ : Mg: Cp ₂ ZrCl ₂ = 10: (10-20): (10-14) :( 0.6-1.0), preferably 10: 15: 12: 0.8, in an atmosphere of ethylene (C ₂ H ₄ ) in an ether solvent (THF) at room temperature (20-22 ° C). The reaction time is 6-10 hours, preferably 8 hours. The total yield of cyclic AOS (1) and (2) is 60-82%, the ratio (1) :( 2) ~ 9: 1, the yield of by-products (3) - (5) does not exceed 8-12%. The conversion of the starting allen is 68-94%. The reaction proceeds according to the scheme:

Carrying out this reaction in the presence of a catalyst Cp ₂ ZrCl ₂ more than 10% mole on the taken 1,2-diene does not lead to a significant increase in the yield of target products (1) and (2). The use of a catalyst of less than 6% mole on the taken 1,2-diene decreases the yield of AOS (1) and (2), which is associated with a decrease in the catalytically active centers in the reaction mass. The syntheses were carried out at a temperature of 20-22 ° C. At higher temperatures, for example 50 ° C, the selectivity of the reaction decreases. At lower temperatures, for example 0 ° C, the reaction rate decreases. A change in the ratios of the starting reagents in the direction of decreasing the EtAlCl ₂ content with respect to the starting acetylene leads to a decrease in the yield of AOS (1) and (2). The reaction should be carried out in an ethylene atmosphere with the slow addition of 1,2-diene to the reaction mass.

Significant differences of the proposed method.

If in the known method pyrophoric (self-igniting in air) AlEt ₃ is used as a starting reagent, then in the proposed method EtAlCl ₂ (not self-igniting in air) is used as a starting reagent.

The method is illustrated by the following examples.

Example 1. In a glass reactor mounted on a magnetic stirrer, in an argon atmosphere, 5 ml of THF, 12 mg-at. magnesium (Mg, powder), then 0.8 mmol of catalyst Cp ₂ ZrCl ₂ , 15 mmol EtAlCl ₂ are added at ~ 0 ° C, ethylene is fed into the reaction mass with stirring (a slight excess pressure of ethylene is created using a U-shaped oil seal), then at a temperature of 20-22 ° C, 10 mmoles of 1,2-nonadiene in 6 ml of THF are slowly added over 4 hours, the reaction mixture is stirred for another 4 hours. 1-Ethyl-2-heptylidenealuminacyclopentane (1) and 1-ethyl-2-methylene-3-hexylaluminacyclopentane are obtained in a ratio of ~ 9: 1 with a total yield of 70%. The output of AOS (1) and (2) was determined by the products of deuterolysis. During the deuterolysis of 1-ethyl-2-heptylidenealuminium cyclopentane (1) and 1-ethyl-2-methylene-3-hexylaluminium cyclopentane (2), 1,4-dideuterondes-4-ene (6) and 2-deutero-3- (2- deuteroethyl) non-1-ene (7).

¹³ C NMR spectrum (δ, ppm, CDCl ₃ , J / Hz) 1,4-dideuterondec-4-ene (6): 13.69 (C ¹ , J _{C, D} = 19.4 Hz), 22.74 ( C ² ), 29.24 (C ³ ), 129.41 (C ⁴ , J _{C, D} = 23.6 Hz), 130.22 (C ⁵ ), 27.32 (C ⁶ ), 29.77 (C ⁷ ), 29.24 (C ⁸ ), 31.86 (C ⁹ ), 22.91 (C ¹⁰ ), 14.18 (C ¹¹ ).

¹³ C NMR spectrum (δ, ppm, CDCl ₃ , J / Hz) 2-deutero-3- (2-deuteroethyl) non-1-ene (7): 113.98 (C ¹ ), 45.76 (C ³ ) , 34.47 (С ⁴ ), 27.43 (С ⁵ ), 29.36 (С ⁶ ), 31.87 (С ⁷ ), 22.34 (С ⁸ ), 14.36 (С ⁹ ), 27.61 (С ¹⁰ ), 13.98 (С ¹¹ , J _{C, D} = 20.4 Hz).

Other examples confirming the method are given in the table:

Reactions were carried out at room temperature (20-22 ° C) in THF, in an ethylene atmosphere. In all experiments, the ratio of products (1) :( 2) ~ 9: 1.

Claims (1)

A method for the joint production of 1-ethyl-2-alkylidenealuminacyclopentanes (1) and 1-ethyl-2-methylene-3-alkylaluminium cyclopentanes (2) of the general formula:

where R = n-C ₄ H ₉ , n-C ₆ H ₁₃ , n-C ₈ H _{17 by the} interaction of 1,2-alkadienes with organoaluminum compounds in the presence of a catalyst of zirconacene dichloride (Cp ₂ ZrCl ₂ ) at room temperature, characterized in that ethyl aluminum dichloride (EtAlCl ₂ ) is used as the organoaluminum compound, the reaction is carried out in the presence of Mg powder at a molar ratio R-CH = C = CH ₂ : EtAlCl ₂ : Mg: Cp ₂ ZrCl ₂ = 10: (10-20) :( 10- 14) :( 0.6-1.0) in an ethylene atmosphere in a THF solution for 6-10 hours