Lewis Acid Catalyzed Domino Ring-Opening Cyclization (DROC) of Azetidines with Alkynes: Synthesis of Tetrahydropyridines

A simple strategy for the synthesis of a variety of tetrahydropyridines in good to excellent yields via a Cu(OTf)2 catalyzed quaternary ammonium salt mediated ring-opening of activated azetidines followed by cyclization with alkynes in a domino fashion (DROC) was described. The formation of the products has been explained by an SN2-type ring-opening of azetidines with alkynes.