The direct arylation of benzo[b]furan, benzo[b]thiophene, and indole has been studied by using aromatic bromides as the aryl source. The protocol employing common reagents and a Pd catalyst has led to the regioselective arylation of these heterocycles at the 2-position. A range of functional groups were tolerated, providing quick access to a variety of arylated benzo-fused heterocycles that would be accessible more elaborately using classical synthetic strategies. This is the first systematic study of the direct arylation of benzo[b]furan.
Keywords: Arylation; Concerted metal deprotonation; C–H activation; Fused-ring systems; Palladium; Regioselectivity; Synthetic methods.