Zinc‐Chloride‐Promoted Domino Reaction of Phenols with Terminal Alkynes under Solvent‐Free Conditions: An Efficient Synthesis of Chromenes

Abstract

A domino one‐pot synthesis of 2 H ‐chromenes and 4 H ‐chromenes starting from phenols and terminal acetylenes in an atom economical reaction under solvent‐free conditions is described. This annulation reaction between phenols with alkynes is promoted by the simple Lewis acid ZnCl 2 . Significantly, to the best of our knowledge, the synthesis of 2 H ‐chromenes is the first of its kind, as it is based on the use of terminal alkyl acetylenes. The described method shows a broad substrate scope and good functional group tolerance.