FeCl₃·6H₂O-Catalyzed Alkenylation of Indoles with Aldehydes

Abstract

FeCl(3)·6H(2)O-catalyzed efficient C3-alkenylation of indoles was realized through the condensation of aldehydes and indole derivatives in the presence of 2 equiv of ethanol at ambient temperature, forming 3-vinylindoles in up to 93% yields. Ethanol promoted formation of the desired products. An obvious solvent effect was observed, and bisindoles were identified as the reaction intermediates.