Silylketenes under Kulinkovich conditions: alkene/ketene exchange versus nucleophilic addition. Application to the stereoselective preparation of vinylcyclopropanols

Silylketenes react under Kulinkovich conditions through two competitive pathways: alkene/ketene exchange versus nucleophilic addition. In both cases, the organotitanium intermediate reacts with an aldehyde to yield an adduct which can undergo an elimination to yield a vinylcyclopropanol or an α,β-unsaturated carbonyl compound.