Studies on the zirconium-mediated alkyne–aldehyde coupling reactions: a facile synthesis of stereodefined allylic alcohols and (Z)-2-en-4-yn-1-ols

An improved zirconium-mediated alkyne–aldehyde cross-coupling reaction has been achieved to afford the stereodefined (Z)-allylic alcohols or 3-iodinated allylic alcohols selectively via protonolysis or iodinolysis of the corresponding five-membered oxazirconacycles. This method has also been successfully applied to the synthesis of (Z)-enynols through cross-coupling reactions of three different components involving alkyne, aldehyde, and alkynyl bromide in a one-pot procedure.