One‐Pot Synthesis of Pyrrolo[1,2‐f]phenanthridines From 1‐Arylpyrroles via Successive Palladium‐Catalyzed Direct Arylations

Abstract

A Pd-catalyzed annulative π-extension reaction of 1-arylpyrroles using 1,2-dihalobenzenes as the coupling partners was investigated. The higher reactivity of pyrrole C2À H bond compared to CÀ H bonds of the aryl unit of 1-arylpyrroles allows selective synthesis of pyrrolo[1,2-f]phenanthridines via successive palladium-catalyzed direct intermolecular followed by intramolecular direct arylation steps. From 1-bromo-2-iodobenzenes bearing substituents at C4-or C5-positions and ortho-, meta-or parasubstituted 1-arylpyrroles, the access to pyrrolo[1,2-f] phenanthridines containing substituents at C5, C6, C7, C8, C10 and/or C11 positions is possible.