Peterson Olefination

The lithio product of the present reagent 1, i.e. α-silylcarbaninon, reacts with a ketone or an aldehyde to give ketenethioacetal 2 in high yield. The ketenethioacetal 2 is a useful intermediate convertible to various compounds. The carbanion 1 is used in the synthesis of cyclopropane from oxirane^2a), diastereoselective alkylation of an α,β-unsaturated ester^2b), etc. The present reagent is so versatile ones that it can be employed not only in conversion of ketone and aldehyde but also in many other fields.