Method for catalyzing alcohol dehydrogenation silicon alkylation by using azacyclo-cabbeen

A nitrogen-heterocyclic carbene and silylation technology, applied in the field of alcohol catalytic dehydrosilylation, can solve the problems of reduced reaction selectivity, complex synthesis process, low catalytic activity, etc., and achieve easy after-treatment, single reaction product, The effect of high catalytic activity

Inactive Publication Date: 2013-02-13
NANKAI UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

These compounds all require complex synthetic processes, and the catalytic activity is low at room temperature and the use of metals cannot be avoided; at the same time, some metals can also catalyze the coupling reaction of silane itself, reducing the selectivity of the reaction; strong Lewis acids such as tris(pentafluorophenyl ) Boron (B(C 6 f 5 ) 3 ) can also be used as a catalyst for this reaction, but it also has the disadvantages of complex synthesis process and low activity

Method used

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  • Method for catalyzing alcohol dehydrogenation silicon alkylation by using azacyclo-cabbeen
  • Method for catalyzing alcohol dehydrogenation silicon alkylation by using azacyclo-cabbeen

Examples

Experimental program
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Embodiment 1

[0014] Example 1: PhSiH(OEt) 2 Synthesis

[0015] 0.0021g (0.012mmol) isopropyl azacarbene was dissolved in 0.4ml deuterated benzene (C 6 D. 6 ), add 0.051g (0.468mmol) of phenylsilane and 0.043g (0.936mmol) of ethanol successively at room temperature, immediately there are violent bubbles released, and the reaction is monitored by NMR. After 0.5 hours, the reaction ends, the conversion rate exceeds 95%, and the selectivity More than 95%.

[0016] Characterization:

[0017] 1 H NMR (C 6 D. 6 , 400MHz): δ7.65-7.75(m, 2H), 7.22–7.19(m, 3H), 5.20(s, 1H), 3.76(q, 4H), 1.13(t, 6H). 13 C NMR (C 6 D. 6 , 101MHz): δ136.13, 134.51, 130.81, 59.47, 18.48.

Embodiment 2

[0018] Example 2: PhSi(OEt) 3 Synthesis

[0019] Put 0.0084g (0.047mmol) of isopropyl azacarbene into a 10ml Shrek tube, add 0.202g (1.87mmol) of phenylsilane and 0.344g (7.48mmol) of ethanol in turn at room temperature, immediately there will be violent release of bubbles , After 1 hour, the reaction was over, no bubbles escaped, nuclear magnetic monitoring showed that the reaction was complete, the conversion rate exceeded 95%, and the product was only PhSi(OEt) 3 . The product was separated by atmospheric distillation, and the separation yield was 70%.

[0020] Characterization:

[0021] 1 H NMR (CDCl 3 , 400MHz): δ7.55-7.65(m, 2H), 7.32–7.19(m, 3H), 3.80(q, 4H), 1.16(t, 6H). 13 C NMR (CDCl 3 , 101MHz): δ134.88, 131.01, 130.42, 127.93, 58.80, 18.30.

Embodiment 3

[0022] Example 3: PhSiH(O i Pr) 2 Synthesis

[0023] Put 0.0084g (0.047mmol) of isopropyl azacarbene into a 10ml Shrek tube, add 0.202g (1.87mmol) of phenylsilane and 0.224g (3.74mmol) of isopropanol successively at room temperature, and there will be bubbles immediately After 0.5 hours, nuclear magnetic monitoring showed that the reaction was complete, and the conversion rate was 90%. The product was separated by atmospheric distillation, and the separation yield was 80%.

[0024] Characterization:

[0025] 1 H NMR (CDCl 3 , 400MHz): δ7.75-7.65(m, 2H), 7.45–7.35(m, 3H), 5.00(s, 1H), 4.27(sept, 2H), 1.16(m, 12H). 13 C NMR (CDCl 3 , 101MHz): δ135.97, 134.24, 130.51, 128.00, 66.48, 25.61.

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Abstract

Provided is a method for catalyzing alcohol dehydrogenation silicon alkylation by using azacyclo-cabbeen. Catalyst azacyclo-cabbeen is dissolved in an organic solvent or directly placed in a schlenk tube (Schlenk tube) and a nuclear magnetism tube, silane and alcohol are sequentially added, a molar ratio of the silane to the alcohol is 1:1-2, a molar ratio of the catalyst azacyclo-cabbeen to the silane is 0.002-0.05:1, reaction is carried out at the normal temperature for 0.5-24h, then a solvent is extracted under a vacuum condition or distillation or column chromatography purification is directly carried out, and the alcohol dehydrogenation silicon alkylation can be carried out to prepare siloxane. The method has the advantages of using small organic molecule azacyclo-cabbeen to serve as a catalytic agent to replace a metal catalyst, is cheap in raw material, easy to prepare, soft in catalysis condition, high in catalytic activity, good in selectivity, easy in aftertreatment and wide in applicable scope of substrate silane, has good functional group tolerance, is single in reaction product, and can efficiently and selectively obtain the siloxane.

Description

technical field [0001] The invention relates to alcohol catalytic dehydrogenation silylation technology, in particular to a method for catalyzing alcohol dehydrogenation silylation with azacyclic carbene. Background technique [0002] For a long time, the silylation of alcohols has been the main method for the preparation of silyl ethers and the protection of various reactants in organic synthesis. Silicone ethers have important applications in the field of organosilicon chemistry and are the synthetic precursors of functionalized silicon-based nanomaterials. In the field of synthetic organic chemistry, silyl ethers are also the most widely used hydroxyl protecting groups. Typically, silyl ethers are obtained through chlorosilanes (R 4-x SiCl x ) and alcohol in a polar solvent such as N,N-dimethylformamide reaction prepared. The disadvantage of this reaction is that it is necessary to add an organic base such as triethylamine to the system to capture the reaction by-prod...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07F7/18
Inventor 崔春明高东静张建颖
Owner NANKAI UNIV
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