A copper-catalyzed reaction between terminal alkynes, acetylenic esters, and oxiranes: efficient synthesis of 2H-pyran-4-carboxylate

摘要

A catalytic reaction between terminal alkynes, acetylenic esters, and oxiranes has been described. This domino transformation serves as a useful sequential and one-pot method for the synthesis of 2H-pyran-4-carboxylate skeletons from the readily available starting materials. In situ-generated copper acetylides treated initially with oxiranes in the presence of copper catalysts and tetrabutylphosphonium salts, followed by addition of propiolates after 60 min to form synthetically important heterocycles.