Benzofuran Derivatives from Alkynyl-Substituted Benzynes and Aryl Halides

A palladium(0)-catalyzed cascade reaction for the efficient synthesis of 2,3-disubstituted benzofuran derivatives <b>3</b> containing a 3-trisubstituted alkene functional group in moderate yields from alkynyl-substituted benzynes <b>1</b> and aryl halides <b>2</b> has been developed. This method provides an efficient and alternative approach to benzofurans which are very useful heterocyclic compounds with biological and pharmacological potentials. A plausible mechanism involving intramolecular ene reaction, intermolecular insertion, and β-H elimination is proposed