Palladium(0)-Catalyzed Heteroannulations of Allenamides: General Synthesis of δ-Carbolines and Benzofuro[3,2- b ]pyridines.

Palladium(0)-catalyzed reactions between allenamides 3 or 4 and aryl iodides/bromides 5 / 6 provide an easy access to δ-carbolines 1 or benzofuro[3,2- b ]pyridines 2 . The reaction constitutes a fast intermolecular assembly that takes place in one pot, and the choice of the phosphine ligand is critical for success. A plausible reaction mechanism is proposed. The reaction is amenable to the synthesis of bis-heteroannulated products.