Palladium‐Catalyzed Efficient Synthesis of Benzofuro[3,2‐ b ]Pyrroles and Pyrrolo[3,2‐ b ]Indoles: Access to Nitrilo Substituted Benzofuro[3,2‐ b ]Indoles and Indolo[3,2‐ b ]Indoles Using DDQ

Abstract We report an elegant method for the construction of fused pyrrole rings via palladium‐catalyzed reactions of aryl iodides with N ‐prop‐2‐ynylated 3‐aminobenzofurans/3‐aminoindoles leading to the general synthesis of benzofuro[3,2‐ b ]pyrroles/pyrrolo[3,2‐ b ]indoles via 3‐(arylidene)‐2,3‐dihydro intermediates. Exposing the intermediates to 2,3‐Dichloro‐5,6‐dicyano‐1,4‐benzoquinone (DDQ) delivered benzofuro[3,2‐ b ]indoles (BFIs) and indolo[3,2‐ b ]indoles (IIs) containing vicinal cyano groups. These transformations constitute a rapid intermolecular assembly through several carbon − carbon bond forming reactions, involving a single electron transfer (SET) process in the crucial steps. Photophysical studies of selected products identified promising candidates for future applications.