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.
The synthesis of β- and γ-hydroxy- and keto-silanes is described, together with that of their carbon analogues. Unlike the α-isomers, the hydroxysilanes do not rearrange to silyl ethers, and the ultraviolet spectra of the silyl ketones is essentially the same as those of the carbon analogues, and unlike that of α-silyl ketones.β-Silyl ketones have a carbonyl-stretching frequency midway between that of ordinary ketones and α-silyl ketones. These effects are discussed.