Silyl-substituted α,β-Unsaturated Ketones from the Reaction of Silylvinylmetallic Reagents with Acid Anhydrides

The reactions of a series of silyl-substituted vinylmetallic reagents with acetic and benzoic anhydride have been investigated as a general route to α,β-unsaturated ketones having a silyl group attached to the carbon–carbon double bond. The reaction has been found to be generally applicable for acetyl derivatives provided low temperatures are used but the reaction with benzoic anhydride gives poorer results. The i.r. and u.v. spectra of the ketones are discussed. The characterization of novel 1,4-dienes obtained as by-products in the syntheses is also described.