Analysis of an unprecedented mechanism for the catalytic hydrosilylation of carbonyl compounds
Analysis of an unprecedented mechanism for the catalytic hydrosilylation of carbonyl compounds
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DOI：
10.1021/ja074477n
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发表时间：
2007-11-28
影响因子：
15
通讯作者：
Toste, F. Dean
中科院分区：
文献类型：
--
作者：
Nolin, Kristine A.;Krumper, Jennifer R.;Toste, F. Dean
本文详细研究了（PPh 3）（2）Re（O）（2）I催化羰基化合物硅氢加成反应的机理。所提出的机理涉及在一个铼-氧代键上添加硅烷Si-H键以形成铼氢化物中间体2，其与羰基底物反应以生成铼醇盐4，其进而提供甲硅烷基醚产物。这一途径运作的有力证据包括：（a）通过X-射线衍射分离和结构表征氢化铼中间体2，（B）证明中间体2在氢化硅烷化反应中的催化能力，（c）H-1和31 P {H-1} NMR和ESI-MS证明2单次转化为1，（d）在工作催化剂体系中观察中间体2，和（e）通过1催化羰基化合物氢化硅烷化的动力学分析。
This work details an in-depth evaluation of an unprecedented mechanism for the hydrosilylation of carbonyl compounds catalyzed by (PPh3)(2)Re(O)(2)I. The proposed mechanism involves addition of a silane Si-H bond across one of the rhenium-oxo bonds to form siloxyrhenium hydride intermediate 2 that reacts with a carbonyl substrate to generate siloxyrhenium alkoxide 4, which, in turn, affords the silyl ether product. Compelling evidence for the operation of this pathway includes the following: (a) isolation and structural characterization by X-ray diffraction of siloxyrhenium hydricle intermediate 2, (b) demonstration of the catalytic competence of intermediate 2 in the hydrosilylation reaction, (c) H-1 and 31P{H-1} NMR and ESI-MS evidence for single-turnover conversion of 2 into 1, (d) observation of intermediate 2 in the working catalyst system, and (e) kinetic analysis of the catalytic hydrosilylation of carbonyl compounds by 1.