Regioselective Silylations of Propargyl and Allyl Pivalates through Ca-Promoted Reductive C(sp3)–O Bond Cleavage

Abstract

A practical protocol for the regioselective preparation of 3-phenylpropargylsilanes and 3-phenylallylsilanes in yields of 36–77 and 48–86%, respectively, from readily accessible 3-phenylpropargyl and 1-phenylallyl pivalates was developed through reductive C(sp³)–O bond cleavage. This method represents the first example of the direct application of vastly abundant calcium granules to a reductive coupling reaction. A broad range of propargylsilanes and allylsilanes are simply prepared using easy-to-handle pivalates and chlorotrimethylsilane under mild catalyst-free and additive-free conditions.