Regioselective Synthesis of 1‐Cyano‐3‐arylindolizines: Construction of Pyrroles via DDQ‐Mediated Ring Closure of Cyclopropyl Pyridines

Abstract

A modular approach to a wide range of 1‐cyano‐3‐(hetero)arylindolizines through aldol‐cyclopropanation‐oxidative cycloisomerization is described where DDQ was utilized for the regioselective synthesis of the pyrrole units from cyclopropyl pyridines for the first time. A key to success is regioselective oxidation of benzylic position by DDQ, which enabled us to access to one regioisomer out of two possible ones. Homo‐dimerization at the C2, C5, or C7 sites of indolizines in the presence of DDQ has been discovered for the first time as well.