Phosphonium Chloride-Catalyzed Dehydrochlorinative Coupling Reactions of Alkyl Halides with Hydridochlorosilanes

The dehydrochlorinative Si−C coupling reactions of various primary and secondary alkyl chlorides with hydridochlorosilanes in the presence of tetrabutylphosphonium chloride as catalyst gave the coupling products with elimination of HCl as a gas. Coupling reactions of activated alkyl chlorides such as benzyl chlorides proceeded at 130 °C, while unactivated organic chlorides such as silylalkyl chlorides and secondary alkyl chlorides required higher reaction temperatures of 150 or 170 °C and longer reaction times. Primary alkyl chlorides reacted with trichlorosilane (1) to give coupling products in good to excellent yields, but secondary alkyl chlorides reacted at a slower rate and gave lower yields of products. Coupling reactions with methyldichlorosilane instead of 1 proceeded at slower rates and gave lower yields of products.