Michael-type addition of O-ethyl- C,O-bis(trimethylsilyl)ketene acetal and its application to the synthesis of α-ylidene-δ-lactones

Abstract

O-Ethyl- C, O-bis(trimethylsilyl)ketene acetal behaves as an active C 2 chain-lenghtening unit when treated with α,β-unsaturated ketones yielding δ-keto-α-trimethylsilylesters with the aid of titanium tetrachloride. The products readily form α-ylidene-δ-lactone derivatives after selective reduction of the ketone carbonyl and subsequent Peterson type olefination.