Preparation and reactions of triarylsilylmethylmetallic reagents

Triarylsilylmethylmetallic reagents have been prepared by several routes: metalation; addition of phenyllithium to vinyltriphenylsilane; direct synthesis; and by halogen–metal exchange. The latter method is highly superior as regards both generality of application and yields. Dibromomethylsilanes undergo halogen-metal exchange at −78°, and reaction of the product with hydrogen bromide serves as a valuable way of converting geminal dibromides to monobromides. The organometallic reagents have been characterized in several ways, in particular by carbonation to give the related carboxylic acid.