title: N-Methyl-Benzothiazolium Salts as Carbon Lewis Acids for Si-H σ-Bond Activation and Catalytic (De)hydrosilylation.
abstract: 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.
authors: School of Chemistry, University of Manchester, Manchester, M13 9PL, UK.
authors: Valerio
authors: V
authors: Fasano
authors: School of Chemistry, University of Manchester, Manchester, M13 9PL, UK.
authors: James E
authors: JE
authors: Radcliffe
authors: School of Chemistry, University of Manchester, Manchester, M13 9PL, UK.
authors: Liam D
authors: LD
authors: Curless
authors: School of Chemistry, University of Manchester, Manchester, M13 9PL, UK.
authors: Michael J
authors: 0000-0001-9975-8302
authors: MJ
authors: Ingleson
keywords: Lewis acids; benzothiazolium salts; frustrated Lewis pairs; hydrosilylation; organocatalysis