Method for synthesizing allyl reagent by using alkali to promote silanization of 1, 3-diene
The synthesis of allylsilane reagents is achieved under non-metal catalytic conditions through alkali-promoted methods, which solves the problems of environmental pollution, high cost and insufficient regional selectivity in traditional methods, and achieves efficient C-Si bond construction and regional selectivity control.
Patent Information
- Application Number
- CN202510327709.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-19
- Publication Date
- 2025-06-24
AI Technical Summary
The existing allyl silane reagent synthesis methods rely on traditional transition metal catalysis, and there are problems of environmental pollution, high costs and insufficient regional selective control.
Using a base-promoting method, a composite was formed by activating the triethylsilane boric acid pinenol ester with sodium tert-butoxide. After two silanizations, a bisilicon compound was formed, and finally a protonation was performed in water to form a target product.
Efficient construction of C-Si bonds under non-metal catalytic conditions to achieve 1,3-diene silanization, solving the environmental pollution and cost problems in traditional methods, and improving regional selective control.
Smart Images
Figure CN120192339A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of organic compound synthesis, and particularly relates to a method for synthesizing allyl reagents by base-promoted 1,3-diene silylation. Background Art
[0002] Allylsilanes are a class of organosilicon compounds known for their versatility, low toxicity, chemical stability, and various reactivity. Their molecular structure combines an alkene and a silylallyl group, making them an integral part of many organic synthesis processes.
[0003] Various synthetic methods for preparing allylsilanes have been designed, including the silylation of allyl organometallic compounds, hydrosilylation of 1,3-dienes and alkenes, and Silyl-Heck cross-coupling. However, the existing synthetic methods for allylsilane reagents rely on traditional transition metal catalysis, which have problems such as environmental pollution and high costs. At the same time, there are also problems with insufficient regioselectivity control. Traditional allyl reagents usually substitute in the α-region of the alkene, and it is difficult to achieve functional group substitution in the β and γ regions. Therefore, we envision whether a multifunctional allyl reagent can be synthesized to synthesize compounds with different substitutions in the α, β, and γ regions through subsequent transformations. Summary of the Invention
[0004] To solve the above technical problems, the object of the present invention is to provide a method for synthesizing allyl reagents by base-promoted 1,3-diene silylation. This method provides a technology for realizing the synthesis of allyl reagents by base-promoted 1,3-diene silylation under the condition of non-metal catalysis for the first time, and solves the problems of environmental pollution and high costs existing in the synthesis of existing allylsilane reagents using traditional transition metal catalysis.
[0005] The technical solution for the present invention to solve the above technical problems is as follows: Provide a method for synthesizing allyl reagents by base-promoted 1,3-diene silylation, including the following steps: (1) Under an argon atmosphere, mix bis(methylthio)trimethylsilane and tetrahydrofuran, dropwise add n-butyllithium at a temperature of -65°C to -85°C, then dropwise add a cinnamaldehyde compound and stir, and then stir overnight at room temperature. After extraction, rotary evaporation concentration, and purification by silica gel column chromatography in sequence, 1,3-butadiene methyl sulfide is obtained; (2) Under an argon atmosphere, mix bis(pinacolato)diboron, platinum on carbon catalyst, cyclohexane, and triethylsilane, stir and react under an oil bath condition. After the reaction is completed, cool to room temperature, obtain a colorless oily liquid after rotary evaporation concentration and purification by silica gel column chromatography, and then perform vacuum distillation to obtain triethylsilylborate pinacol ester; (3) Mix sodium tert-butoxide, the methyl sulfide of 1,3-butadiene obtained in step (1), and the triethylsilyl borate pinacol ester obtained in step (2) with tetrahydrofuran, then heat for reaction, cool to room temperature, quench the reaction with saturated ammonium chloride solution, add ethyl acetate for dilution, concentrate by rotary evaporation of the organic phase and purify by silica gel column chromatography to obtain the disilylated allyl compound.
[0006] Furthermore, in step (1), the chemical structural formula of the cinnamaldehyde compound is as follows: ; wherein, R is one of hydrogen, methyl, methoxy, ethoxy, dimethylamino, dimethylaniline, and phenyl.
[0007] Furthermore, in step (1), the molar volume ratio of bis(methylthio)trimethylsilane, tetrahydrofuran, n-butyllithium, and the cinnamaldehyde compound is 8 - 12 mmol: 20 - 30 mL: 10 - 15 mmol: 8 - 12 mmol.
[0008] Furthermore, the molar volume ratio of bis(methylthio)trimethylsilane, tetrahydrofuran, n-butyllithium, and the cinnamaldehyde compound is 10 mmol: 25 mL: 12 mmol: 10 mmol.
[0009] Furthermore, in step (1), extraction is carried out using ethyl acetate.
[0010] Furthermore, in step (2), the molar volume ratio of bis(pinacolato)diboron, platinum-carbon catalyst, cyclohexane, and triethylsilane is 10 - 15 mmol: 0.1 mmol: 4 - 6 mL: 4 - 6 mmol.
[0011] Furthermore, the molar volume ratio of bis(pinacolato)diboron, platinum-carbon catalyst, cyclohexane, and triethylsilane is 12.5 mmol: 0.1 mmol: 5.0 mL: 5.0 mmol.
[0012] Furthermore, in step (2), at 70 o °C ~ 90 o °C, stir and react for 10 - 15 h under an oil bath condition.
[0013] Furthermore, in step (3), the molar volume ratio of sodium tert-butoxide, the methyl sulfide of 1,3-butadiene, the triethylsilyl borate pinacol ester, and tetrahydrofuran is 0.5 - 0.8 mmol: 0.2 mmol: 0.8 - 1.2 mmol: 3 - 5 mL.
[0014] Further, the molar volume ratio of sodium tert-butoxide, methyl sulfide of 1,3-butadiene, triethylsilylboronic acid pinacol ester, and tetrahydrofuran is 0.7 mmol: 0.2 mmol: 1.0 mmol: 4.0 mL.
[0015] Further, in step (3), the reaction is heated at 60 °C to 80 °C for 20 to 30 h.
[0016] Further, the eluent for silica gel column chromatography is petroleum ether.
[0017] Further, tetrahydrofuran needs to be pre-dried with sodium.
[0018] The present invention also discloses a disilylated allyl compound prepared by the method for synthesizing an allyl reagent by alkali-promoted 1,3-diene silylation as described above.
[0019] Further, the chemical structure of the disilylated allyl compound is shown as follows: .
[0020] The present invention has the following beneficial effects: 1. In the method of the present invention, 1,3-diene reacts with sodium tert-butoxide to activate triethylsilylboronic acid pinacol ester to form a complex, which undergoes two silylation reactions to generate a disilicon compound with a carbanion, and is protonated by water during post-treatment to generate the target product. Using this method, C-Si bonds can be efficiently constructed, and 1,3-diene silylation can be achieved, having great application prospects.
[0021] 2. The method of the present invention provides the first technology for realizing the synthesis of an allyl reagent by 1,3-diene silylation under the condition of non-metal catalysis using an alkali (sodium tert-butoxide), solving the problems of environmental pollution and high cost existing in the synthesis of allyl silanes using traditional transition metal catalysis. BRIEF DESCRIPTION OF THE DRAWINGS
[0022] Figure 1 It is the reaction schematic diagram of step (1) in Example 1; Figure 2 It is the reaction schematic diagram of step (2) in Example 1; Figure 3 It is the reaction schematic diagram of step (3) in Example 1; Figure 4 It is the 1 1H NMR spectrum of the disilylated allyl compound prepared in Example 1; Figure 5 It is the 13 13C NMR spectrum of the disilylated allyl compound prepared in Example 1. DETAILED DESCRIPTION OF THE INVENTION
[0023] The principles and features of the present invention are described below. The examples given are only used to explain the present invention and are not intended to limit the scope of the present invention. For those without specific conditions noted in the examples, they are carried out according to conventional conditions or the conditions recommended by the manufacturer. For reagents or instruments without the manufacturer noted, they are all conventional products that can be obtained through commercial purchase.
[0024] Example 1 A method for synthesizing allyl reagents by base-promoted 1,3-diene silylation, comprising the following steps: (1) Under an argon atmosphere, 10 mmol of bis(methylthio)trimethylsilane and 25 mL of tetrahydrofuran were mixed, 12 mmol of n-butyllithium was added dropwise at -78 °C, then 10 mmol of cinnamaldehyde was added dropwise and stirred, and then stirred overnight at room temperature. It was successively extracted with ethyl acetate, concentrated by rotary evaporation, and purified by silica gel column chromatography (the eluent was petroleum ether) to obtain the methyl sulfide of 1,3-butadiene (the reaction process is as Figure 1 shown); (2) Under an argon atmosphere, 12.5 mmol of bis(pinacolato)diboron, 0.1 mmol of platinum-carbon catalyst, 5 mL of cyclohexane, and 5 mmol of triethylsilane were mixed, and stirred and reacted for 12 h under an 80 o °C oil bath condition. After the reaction was completed, it was cooled to room temperature, concentrated by rotary evaporation, and purified by silica gel column chromatography to obtain a colorless oily liquid, and then distilled under reduced pressure to obtain triethylsilyl pinacol borate Et3Si-Bpin (the reaction process is as Figure 2 shown); (3) 0.7 mmol of sodium tert-butoxide, 0.2 mmol of the methyl sulfide of 1,3-butadiene obtained in step (1), 1 mmol of triethylsilyl pinacol borate obtained in step (2) were mixed with 4 mL of tetrahydrofuran, and then heated and reacted at 70 °C for 24 h. Then it was cooled to room temperature, the reaction was quenched with saturated ammonium chloride solution, diluted with ethyl acetate, the organic phase was concentrated by rotary evaporation and purified by silica gel column chromatography to obtain the disilylated allyl compound (the reaction process is as Figure 3 shown).
[0025] Example 2 A method for synthesizing allyl reagents by base-promoted 1,3-diene silylation, comprising the following steps: (1) Under an argon atmosphere, 8 mmol of bis(methylthio)trimethylsilane and 20 mL of tetrahydrofuran were mixed, 10 mmol of n-butyllithium was added dropwise at -65 °C, then 8 mmol of p-methylcinnamaldehyde was added dropwise and stirred, and then stirred overnight at room temperature. It was successively extracted with ethyl acetate, concentrated by rotary evaporation, and purified by silica gel column chromatography (the eluent was petroleum ether) to obtain the methyl sulfide of 1,3-butadiene; (2) Under an argon atmosphere, 10 mmol of bis(pinacolato)diboron, 0.1 mmol of platinum on carbon catalyst, 4 mL of cyclohexane, and 4 mmol of triethylsilane were mixed, and stirred at 70 o °C in an oil bath for 10 h. After the reaction was completed, it was cooled to room temperature, concentrated by rotary evaporation, purified by silica gel column chromatography to obtain a colorless oily liquid, and then distilled under reduced pressure to obtain triethylsilyl pinacol borate; (3) 0.5 mmol of sodium tert-butoxide, 0.2 mmol of the methyl sulfide of 1,3-butadiene obtained in step (1), 0.8 mmol of triethylsilyl pinacol borate obtained in step (2) were mixed with 3 mL of tetrahydrofuran, and then heated and reacted at 60 °C for 20 h. Then it was cooled to room temperature, the reaction was quenched with saturated ammonium chloride solution, diluted with ethyl acetate, and the organic phase was concentrated by rotary evaporation and purified by silica gel column chromatography to obtain a disilylated allyl compound.
[0026] Example 3 A method for synthesizing an allyl reagent by alkali-promoted 1,3-diene silylation, comprising the following steps: (1) Under an argon atmosphere, 12 mmol of bis(methylthio)trimethylsilane and 30 mL of tetrahydrofuran were mixed, 15 mmol of n-butyllithium was added dropwise at -85 °C, then 12 mmol of p-methoxycinnamaldehyde was added dropwise and stirred, and then stirred overnight at room temperature. It was successively extracted with ethyl acetate, concentrated by rotary evaporation, and purified by silica gel column chromatography (the eluent was petroleum ether) to obtain the methyl sulfide of 1,3-butadiene; (2) Under an argon atmosphere, 15 mmol of bis(pinacolato)diboron, 0.1 mmol of platinum on carbon catalyst, 6 mL of cyclohexane, and 6 mmol of triethylsilane were mixed, and stirred at 90 o °C in an oil bath for 15 h. After the reaction was completed, it was cooled to room temperature, concentrated by rotary evaporation, purified by silica gel column chromatography to obtain a colorless oily liquid, and then distilled under reduced pressure to obtain triethylsilyl pinacol borate; (3) 0.8 mmol of sodium tert-butoxide, 0.2 mmol of the methyl sulfide of 1,3-butadiene obtained in step (1), 1.2 mmol of triethylsilyl pinacol borate obtained in step (2) were mixed with 5 mL of tetrahydrofuran, and then heated and reacted at 80 °C for 30 h. Then it was cooled to room temperature, the reaction was quenched with saturated ammonium chloride solution, diluted with ethyl acetate, and the organic phase was concentrated by rotary evaporation and purified by silica gel column chromatography to obtain a disilylated allyl compound.
[0027] Test Example 1 The disilylated allyl compound prepared in Example 1 was subjected to nuclear magnetic resonance detection, 1 1H and 13 13C NMR spectra are respectively asFigure 4 and 5 as shown
[0028] 1 1H NMR (400 MHz, CDCl3) δ 7.23 (t, J J = 7.6 Hz, 2 H), 7.07 (t, J J = 9.2 Hz, 3 H), 5.77 (dd, J J = 14.8, 10.0 Hz, 1 H), 5.28 (dd, J J = 14.8, 10.4 Hz, 1 H), 3.10 (d, J J = 10.0 Hz, 1 H), 2.70 (d, J J = 10.4 Hz, 1 H), 2.05 (s, 3 H), 0.90 (q, J J = 7.6 Hz, 18 H), 0.60 - 0.51 (m, 12 H). 13 13C NMR (100 MHz, CDCl3) δ 143.3, 129.7, 128.1, 127.9, 127.3, 124.3, 39.4, 36.5, 16.0, 7.5, 7.5, 2.5, 2.4. HRMS (ESI): Calculated for C 23 H 42 SSi2 [M - H] + : 405.2468; Found: 405.2461.
[0029] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, or improvements made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.
Claims
1. A method for synthesizing an allyl reagent by alkali-promoting 1,3-diene silylation, characterized in that: The following steps are involved: (1) Under an argon atmosphere, bis(methylthio)trimethylsilane and tetrahydrofuran are mixed, n-butyl lithium is added dropwise at a temperature of -65°C to -85°C, and then a cinnamaldehyde compound is added dropwise and stirred, and then stirred at room temperature overnight, and then extracted, concentrated by rotary evaporation, and purified by silica gel column chromatography to obtain methyl sulfide of 1,3-butadiene; (2) In an argon atmosphere, bis(pinacol)diboron, platinum-carbon catalyst, cyclohexane and triethylsilane are mixed, stirred and reacted in an oil bath. After the reaction is completed, the mixture is cooled to room temperature, concentrated by rotary evaporation and purified by silica gel column chromatography to obtain a colorless oily liquid, which is then distilled under reduced pressure to obtain triethylsilylboronic acid pinacol ester; (3) Sodium tert-butoxide, the methyl sulfide of 1,3-butadiene obtained in step (1), and triethylsilylboronic acid pinacol ester obtained in step (2) are mixed with tetrahydrofuran and heated to react, then cooled to room temperature and quenched with saturated ammonium chloride solution, and then diluted with ethyl acetate, and the organic phase is concentrated by rotary evaporation and purified by silica gel column chromatography to obtain a disilylated allyl compound.
2. The method for synthesizing an allyl reagent by alkali-promoted 1,3-diene silylation as claimed in claim 1, characterized in that: In step (1), the chemical structural formula of the cinnamaldehyde compound is as follows: ； Wherein, R is one of hydrogen, methyl, methoxy, ethoxy, dimethylamino, ditoluidine and phenyl.
3. The method for synthesizing an allyl reagent by alkali-promoted 1,3-diene silylation as claimed in claim 1, characterized in that: In step (1), the molar volume ratio of the bis(methylthio)trimethylsilane, tetrahydrofuran, n-butyl lithium and cinnamaldehyde compound is 8-12 mmol: 20-30 mL: 10-15 mmol: 8-12 mmol.
4. The method for synthesizing an allyl reagent by alkali-promoted 1,3-diene silylation as claimed in claim 1, characterized in that: In step (1), ethyl acetate is used for extraction.
5. The method for synthesizing an allyl reagent by alkali-promoted 1,3-diene silylation as claimed in claim 1, characterized in that: In step (2), the molar volume ratio of the bis(pinacol)diboron, the platinum carbon catalyst, cyclohexane and triethylsilane is 10-15 mmol: 0.1 mmol: 4-6 mL: 4-6 mmol.
6. The method for synthesizing an allyl reagent by alkali-promoted 1,3-diene silylation as claimed in claim 1, characterized in that: In step (2), at 70 o C~90 o The reaction was stirred in an oil bath at C for 10-15 h.
7. The method for synthesizing an allyl reagent by alkali-promoted 1,3-diene silylation as claimed in claim 1, characterized in that: In step (3), the molar volume ratio of the sodium tert-butoxide, methyl sulfide of 1,3-butadiene, triethylsilylboronic acid pinacol ester and tetrahydrofuran is 0.5-0.8 mmol: 0.2 mmol: 0.8-1.2 mmol: 3-5 mL.
8. The method for synthesizing an allyl reagent by alkali-promoted 1,3-diene silylation as claimed in claim 1, characterized in that: In step (3), the reaction is heated at 60°C to 80°C for 20 to 30 h.
9. The method for synthesizing an allyl reagent by alkali-promoted 1,3-diene silylation as claimed in claim 1, characterized in that: The eluent for silica gel column chromatography was petroleum ether.
10. A disilylated allyl compound obtained by the method for synthesizing an allyl reagent by silylation of 1,3-diene promoted by a base as claimed in any one of claims 1 to 9.