A versatile palladium-mediated three-component reaction for the one-pot synthesis of stereodefined 3-arylidene-(or 3-alkenylidene-)tetrahydrofurans

A one-pot reaction between equimolecular amounts of various propargyl alcoh ols, Michael acceptors, and unsaturated halides (or triflates) in the prese nce of a palladium(0) catalyst provides :a simple and flexible entry into h ighly substituted 3-arylidene(or 3-alkenylidene)-tetrahydrofurans. The effi ciency of this palladium-mediated three-component reaction has been shown t o be strongly influenced by the nature of the catalyst system, and in this regard, a palladium(0) catalyst generated in situ by reduction of PdCl2(PPh 3)(2) with n-butyllithium has been found particularly effective.