Gold(I)-Catalyzed Tandem Cyclization/Hydroarylation of <i>o</i>-Alkynylphenols with Haloalkynes

Abstract

A convenient and mild protocol for the gold-catalyzed intermolecular coupling of <i>o</i>-alkynylphenols with haloalkynes to give vinyl benzofurans is reported. In this work, the gold catalyst SIPrAuCl and the co-catalyst NaBARF would corporately promote the intramolecular cyclization of the <i>o</i>-alkynylphenol to benzofuran, and then a selective hydroarylation of benzofuran to haloalkyne was catalyzed by the same catalysts. Computational studies suggest that the hydroarylation process takes place via a concerted nucleophilic attack pathway of the benzofuran to the C2 carbon of the activated haloalkyne, and reveal the original driving force of this hydroarylation process.