Gold(I)-Catalyzed Selective Hydroarylation of Indoles with Haloalkynes

A highly regio- and stereoselective synthesis of a Z-alkenyl indole via the gold-catalyzed addition of an indole to a haloalkyne was developed. In the presence of gold catalyst SIPrAuCl and cocatalyst NaBARF, a broad range of indoles react with haloalkynes to afford Z-alkenyl indoles with high selectivity at room temperature. Computational studies suggest that the hydroarylation reaction takes place via a concerted C2 addition pathway of the indole to the activated haloalkyne.