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

A convenient and mild protocol for the gold-catalyzed intermolecular coupling of o-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 o-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.

Automated summary

A convenient and mild gold-catalyzed protocol for the intermolecular coupling of o-alkynylphenols with haloalkynes to yield vinyl benzofurans has been reported. The reaction involves the intramolecular cyclization of the o-alkynylphenol to benzofuran, followed by a selective hydroarylation of the benzofuran to haloalkyne. Computational studies have provided insights into the reaction mechanism.