RU2295528C1 - Method for preparing 1-chloro-3,4-dialkyl-2,5-bis-(trimethylsilyl)-aluminacyclopenta-2,4-dienes - Google Patents

Abstract

FIELD: chemistry of organometallic compounds, chemical technology.

SUBSTANCE: invention relates to metalloorganic synthesis, namely, to a method for synthesis of 1-hloro-3,4-dialkyl-2,5-bis-(trimethylsilyl)-aluminacyclopenta-2,4-dienes of the general formula (1):

wherein R means n-C₃H₇, n-C₄H₉, n-CH₁₃. Method involves interaction of disubstituted acetylenes with AlCl₃ and metallic Mg in the presence of zirconacene dichloride as a catalyst in tetrahydrofuran (TGF) medium, in argon atmosphere, at room temperature for 14-18 h. Synthesized compounds can be used as a component of catalytic system used in processes of oligomerization and polymerization of olefins and diene hydrocarbons, in fine industrial organic and metalloorganic synthesis, and in synthesis of biologically active preparations.

EFFECT: improved method of synthesis.

2 cl, 1 tbl, 1 ex

Description

The present invention relates to the field of organometallic synthesis, specifically to a method for producing 1-chloro-3,4-dialkyl-2,5-bis (trimethylsilyl) aluminaminocyclopenta-2,4-dienes of the general formula (1):

where R = n-C ₃ H ₇ , n-C ₄ H ₉ , n-C ₆ H ₁₃

These compounds can be used as components of catalytic systems in the processes of oligomerization and polymerization of olefins and diene hydrocarbons, in fine, industrial organic and organometallic synthesis, as well as in the synthesis of biologically active preparations.

The known method [Hongyun Fang, Changjia Zhao, Guotao Li and Zhenfeng Xi. Reaction of aluminacyclopentadienes with aldehydes affording cyclopentadiene derivatives. Tetrahedron, 59, (2003), 3779-3786] for the preparation of 1-chloro-2,3,4,5-tetraalkylaluminacyclopenta-2,4-diene (3) by the reaction of 1,4-dilithio-1,3-diene obtained from 1,4-diiod-1,3-butadiene and t-BuLi, with aluminum trichloride according to the scheme:

The known method does not allow to obtain 1-chloro-3,4-dialkyl-2,5-bis (trimethylsilyl) aluminacyclopenta-2,4-diene (1).

The known method [U. M. Dzhemilev, A. G. Ibrahimov, L. O. Khafizova, L. R. Yakupova, L. M. Khalilov. Cycloalumination of acetylenes and 1,4-enins with the participation of Zr-containing catalysts. Journal of Organic Chemistry, 2005, 41, 684] for the preparation of cyclic organoaluminum compounds (3) by the reaction of disubstituted acetylenes with ethyl aluminum dichloride (EtAlCl ₂ ) in the presence of a catalyst of zirconacene dichloride (Cp ₂ ZrCl ₂ ) with stirring for 8 hours according to the scheme:

The known method does not allow to obtain 1-chloro-3,4-dialkyl-2,5-bis (trimethylsilyl) aluminacyclopenta-2,4-diene (1).

Thus, in the literature there is no information on the synthesis of 1-chloro-3,4-dialkyl-2,5-bis (trimethylsilyl) aluminaminocyclopenta-2,4-dienes of the general formula (1).

A new method is proposed for the synthesis of 1-chloro-3,4-dialkyl-2,5-bis (trimethylsilyl) aluminacyclopenta-2,4-dienes (1).

где R=н-С₃Н₇, н-С₄Н₉, н-С₆Н₁₃ с AlCl₃ с металлическим Mg в присутствии катализатора цирконацендихлорида (Cp₂ZrCl₂), взятых в мольном соотношении

: AlCl₃ : Mg : Cp₂ZrCl₂ = 10:(5-10):(5-10):(1.0-1.4), предпочтительно 10:8:8:1.2. Реакцию проводят в атмосфере аргона при комнатной температуре (~20°С) и атмосферном давлении. Время реакции 14-18 часов, выход целевых продуктов 42-64%. В качестве растворителя необходимо использовать ТГФ, в других эфирных растворителях (диэтиловый эфир, диоксан) реакция идет неселективно и выход целевых продуктов (1) значительно снижается.The essence of the method consists in the interaction of silicon-containing acetylenes of the formula

where R = n — C ₃ H ₇ , n — C ₄ H ₉ , n — C ₆ H ₁₃ with AlCl ₃ with metallic Mg in the presence of a catalyst of zirconacene dichloride (Cp ₂ ZrCl ₂ ), taken in molar ratio

: AlCl ₃ : Mg: Cp ₂ ZrCl ₂ = 10: (5-10) :( 5-10) :( 1.0-1.4), preferably 10: 8: 8: 1.2. The reaction is carried out in an argon atmosphere at room temperature (~ 20 ° C) and atmospheric pressure. The reaction time is 14-18 hours, the yield of the target products is 42-64%. As a solvent, it is necessary to use THF; in other ether solvents (diethyl ether, dioxane), the reaction is non-selective and the yield of the target products (1) is significantly reduced.

The reaction proceeds according to the scheme:

The target products (1) are formed only with the participation of disubstituted acetylene, AlCl ₃ , metallic Mg and catalyst Cp ₂ ZrCl ₂ . In the presence of other catalysts based on transition metal complexes (for example, Zr (acac) ₄ , Cp ₂ TiCl ₂ , Pd (acac) ₂ , Ni (acac) ₂ , Fe (acac) ₃ ), the target products (1) are not formed.

Carrying out the reaction in the presence of a Cp ₂ ZrCl ₂ catalyst greater than 1.4 mmol does not lead to a significant increase in the yield of the target products (1). The use of Cp ₂ ZrCl ₂ in the reaction of the catalyst less than 1 mmol reduces the yield of AOS (1), which is associated with a decrease in catalytically active centers in the reaction mass. The experiments were carried out at room temperature ~ 20 ° C. At a higher temperature (for example, 50 ° C), the content of seal products increases, at a lower temperature (for example, 0 ° C) the reaction rate decreases.

A change in the ratio of the starting reagents in the direction of increasing AlCl ₃ content with respect to acetylene does not lead to a significant increase in the yield of the target products (1). A decrease in the amount of AlCl ₃ with respect to acetylene reduces the yield of AOS (1).

Significant differences of the proposed method:

In the proposed method, silicon-containing acetylene and a salt of trichloride aluminum (AlCl ₃ ) are used as starting compounds, and in the known method, an organoaluminum compound ethylaluminium dichloride (EtAlCl ₂ ) and alkyl substituted acetylenes.

The proposed method has the following advantages:

The method allows to obtain with high selectivity 1-chloro-3,4-dialkyl-2,5-bis (trimethylsilyl) aluminacyclopenta-2,4-dienes (1), 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, 10 ml of THF, 1.2 mmol of Cp ₂ ZrCl ₂ , 10 mmol of trimethylsilylhexine-1, 8 mg-at.Mg (powder) and at a temperature of ~ 0 are placed in an argon atmosphere ° C is added 8 mmol AlCl _3. The temperature was brought to room temperature and stirred for 16 hours. Get individual 1-chloro-3,4-di-n-butyl-2,5-bis (trimethylsilyl) aluminaminocyclopenta-2,4-diene (1). The yield of the target product was determined by the hydrolysis product. Upon hydrolysis of AOS (1), [(2-butyl-3- (trimethylsilyl) methylidene) -1-heptenyl] trimethyl-silane (5) is formed in 55% yield, and during deuterolysis, respectively [(2-butyl-3- ( trimethylsilyl) -1-deuteromethylidene) -1-deuterohept-1-enyl] trimethylsilane (6).

Spectral characteristics of the products of hydrolysis (5) and deuterolysis (6).

¹ H NMR Spectrum (CDCl ₃ , δ, ppm) [(2-butyl-3- (trimethylsilyl) methylidene) -1-heptenyl] trimethylsilane (5): 0.30-0.42 (18H, -C-Si- ( С Н ₃ ) ₃ ), 0.85-0.95 m (6Н, СН ₃ ), 1.1-1.5 m (8Н, СН ₂ ), 1.95-2.10 m (4Н, = С-CH ₂ ), 5.52-5.83 m (2Н, -C = CH-).

¹³ C NMR Spectrum (δ, ppm) [(2-butyl-3- (trimethylsilyl) methylidene) -1-heptenyl] trimethylsilane (5): 0.28 (C ^{13, 14, 15, 16, 17, 18} ) 14.15 (C ^{7, 11} ), 23.21 (C ^{6, 10} ), 31.82 (C ^{5, 9} ), 33.93 (C ^{4, 8} ), 125.32 (C ^{2, 3} ), 161.08 (C ^{1, 12} ).

¹ H NMR Spectrum (CDCl ₃ , δ, ppm) [(2-butyl-3- (trimethylsilyl) -1-deuteromethylidene) -1-deuterohept-1-enyl] trimethylsilane (6): 0.3 0-0.46 ( 18H, -С-Si- (С Н ₃ ) ₃ ), 0.85-0.94 m (6Н, СН ₃ ), 1.15-1.51 m (8Н, СН ₃ ), 1.93-2.10 m (4Н, = C-CH ₂ ) .

¹³ C NMR (δ, ppm) [(2-butyl-3- (trimethylsilyl) -1-deyterometiliden) -1-deyterogept-1-enyl] trimethylsilane (6): 0.22 (C ^{13, 14, 15 , 16, 17, 18} ), 14.13 (С ^{7, 11} ), 23.15 (С ^{6, 10} ), 31.78 (С ^{5, 9} ), 33.89 (С ^{4, 8} ), ^* (С ^{1, 12} ) (signal is not observed), 160.76 t (C ^{2, 3} ).

Other examples confirming the method are shown in table 1.

Table 1. №№

Molar ratio

: AlCl ₃ : Mg: Cp ₂ ZrCl ₂ , mmol Reaction time, hour Yield (1),% one Trimethylsilylhexine-1 10: 8: 8: 1.2 16 55 2 - 10: 10: 10: 1.2 16 60 3 - 10: 5: 5: 1.2 16 45 four - 10: 8: 8: 1.4 16 64 5 - 10: 8: 8: 1.0 16 42 6 - 10: 8: 8: 1.2 eighteen 58 7 - 10: 8: 8: 1.2 fourteen 52 8 - 10: 8: 8: 1.2 16 49 9 Trimethylsilylpentin-1 10: 8: 8: 1.2 16 57 10 Trimethylsilyloctin-1 10: 8: 8: 1.2 16 fifty

All experiments were carried out at room temperature (~ 20 ° C) in THF.

Claims (1)

The method of obtaining 1-chloro-3,4-dialkyl-2,5-bis (trimethylsilyl) aluminaminocyclopenta-2,4-dienes of the General formula (I)

where R is n-C ₃ H ₇ , n-C ₄ H ₉ , n-C ₆ H ₁₃ , characterized in that the disubstituted acetylene of the general formula

where R is n-C ₃ H ₇ , n-C ₄ H ₉ , n-C ₆ H ₁₃ , interacts with AlCl ₃ and metallic Mg in the presence of a catalyst of zirconacene dichloride (Cp ₂ ZrCl ₂ ) in a molar ratio

AlCl ₃ : Mg: Cp ₂ ZrCl ₂ = 10: (5-10) :( 5-10) :( 1.0-1.4) in an argon atmosphere at normal pressure in THF for 14-18 hours.