Rhodium-Catalyzed Carbon-Silicon Bond Activation for Synthesis of Benzosilole Derivatives
Rhodium-Catalyzed Carbon-Silicon Bond Activation for Synthesis of Benzosilole Derivatives
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DOI：
10.1021/ja3096174
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发表时间：
2012-11-28
影响因子：
15
通讯作者：
Chatani, Naoto
中科院分区：
文献类型：
--
作者：
Onoe, Masahiro;Baba, Katsuaki;Chatani, Naoto
采用铑催化2-三甲基硅基苯硼酸与内炔的偶联反应，合成了2,3-二取代苯甲硅酮衍生物。一系列官能团，包括酮、酯、胺、芳基溴和杂环芳烃，是相容的，这提供了快速获取各种苯并唑的途径。顺序的2倍耦合使得不对称取代1,5-二氢-1,5-二硅氧烷的模块化合成成为可能，这是一种有机电子学中感兴趣的pi扩展分子。从机理上讲，该反应涉及到三烷基硅基中C（烷基）-Si键的断裂，通常需要极其苛刻的激活条件。机制研究，包括取代基的影响，揭示了C-Si的键裂解不是通过超配硅物种进行的，而是通过铑介导的活化过程进行的。并证明了该反应在催化不对称合成硅手性苯甲硅酮中的潜在应用。
A rhodium-catalyzed coupling reaction of 2-trimethylsilylphenylboronic acid with internal alkynes is developed for the synthesis of 2,3-disubstituted benzosilole derivatives. A range of functional groups, encompassing ketones, esters, amines, aryl bromides, and heteroarenes, are compatible, which provides rapid access to diverse benzosiloles. Sequential 2-fold coupling enables modular synthesis of asymmetrically substituted 1,5-dihydro-1,5-disila-s-indacene, a pi-extended molecule of interest in organic electronics. In terms of the mechanism, the reaction involves cleavage of a C(alkyl)-Si bond in a trialkylsilyl group, which normally requires extremely harsh conditions for activation. Mechanistic studies, including effects of substituents, reveal C-Si that bond cleavage does not proceed through a hypercoordinated silicon species, but rather through a rhodium-mediated-activation process. The potential use of the reaction in catalytic asymmetric synthesis of Si-chiral benzosiloles is also, demonstrated.