N-Methyl-Benzothiazolium Salts as Carbon Lewis Acids for Si-H σ-Bond Activation and Catalytic (De)hydrosilylation.
N-Methyl-Benzothiazolium Salts as Carbon Lewis Acids for Si-H σ-Bond Activation and Catalytic (De)hydrosilylation.
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DOI：
10.1002/chem.201604613
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发表时间：
2017-01-01
期刊：
影响因子：
--
通讯作者：
Ingleson MJ
中科院分区：
文献类型：
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作者：
Fasano V;Radcliffe JE;Curless LD;Ingleson MJ
N-−Me-苯并噻唑盐是一类能够激活Si-−-H-σ键的新型路易斯酸类化合物。这些以碳为中心的路易斯酸对氢化物的路易斯酸度与广泛用于Si−Hσ-键活化的三芳基硼烷的刘易斯酸度相当。然而，与三芳基硼烷相比，它们对Et3PO和H2O等硬Lewis碱表现出较低的Lewis酸度。N-−-Me-苯并噻唑盐是一系列硅氢加成反应和硅氢脱氢反应的有效催化剂。在这些阳离子中明智地选择C2芳基取代基，能够调节亲电中心周围的空间和电子环境，以产生更活跃的催化剂。最后，相关的苯并恶唑和苯并咪唑盐也被发现对Si−氢键的活化和亚胺的硅氢化反应具有催化活性。
N−Me‐Benzothiazolium salts are introduced as a new family of Lewis acids able to activate Si−H σ bonds. These carbon‐centred Lewis acids were demonstrated to have comparable Lewis acidity towards hydride as found for the triarylboranes widely used in Si−H σ‐bond activation. However, they display low Lewis acidity towards hard Lewis bases such as Et3PO and H2O in contrast to triarylboranes. The N−Me‐benzothiazolium salts are effective catalysts for a range of hydrosilylation and dehydrosilylation reactions. Judicious selection of the C2 aryl substituent in these cations enables tuning of the steric and electronic environment around the electrophilic centre to generate more active catalysts. Finally, related benzoxazolium and benzimidazolium salts were found also to be active for Si−H bond activation and as catalysts for the hydrosilylation of imines.