B(C6F5)3 catalyzed hydrosilation of enones and silyl enol ethers

被引：146

作者：

Blackwell, JM ^{[1
]}

Morrison, DJ ^{[1
]}

Piers, WE ^{[1
]}

机构：

[1] Univ Calgary, Dept Chem, Calgary, AB T2N 1N4, Canada

来源：

TETRAHEDRON | 2002年 / 58卷 / 41期

基金：

加拿大自然科学与工程研究理事会;

关键词：

Lewis acid catalysis; hydrosilation; enones; silylenol ethers; tris-(pentafluorophenyl)borane;

D O I：

10.1016/S0040-4020(02)00974-2

中图分类号：

O62 [有机化学];

学科分类号：

070303 ; 081704 ;

摘要：

The 1,4 hydrosilation of a variety of simple alpha,beta-unsaturated enones as catalyzed by B(C6F5)(3) (1-2%) is described. For substrates with no steric hindrance near the beta-carbon, 1,4 addition of silane is very clean; in other instances, 1,2 hydrosilation is competitive. The reaction is facile with five commercially available silane reagents. For two examples, a novel hydrosilation of the resulting silylenol ethers was also observed. The net trans stereochemistry of H-Si addition to the silylenol ether C=C bond was established and points to a stepwise mechanism for this reaction. This was supported by the observation and full spectroscopic characterization of a silylcarboxonium ion intermediate with an [HB(C6F5)(3)](-) counteranion in the hydrosilation of the silylenol ether derived from 4,4-dimethyl-2-cyclohexen-1-one and PhMe2SiH. (C) 2002 Elsevier Science Ltd. All rights reserved.

引用

页码：8247 / 8254

页数：8

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