Iron-Catalyzed Intramolecular Alkyne–Carbonyl Metathesis: A New Cyclization Strategy for the Synthesis of Benzocarbazole and Azepino[1,2-a]indole Derivatives

Abstract

An efficient synthesis of benzocarbazoles and benzo[3,4]azepino[1,2-a]indole derivatives through an FeCl3-catalyzed alkyne–aldehyde metathesis reaction is described. Structurally diverse benzo[a]carbazoles, benzo[c]carbazoles, and benzo[3,4]azepino[1,2-a]indoles have been achieved in good yields with high regio- and chemoselectivity in the presence of catalytic, inexpensive, and environmentally friendly FeCl3­ as a catalyst.