An Expedient New Synthesis of Substituted Carbazoles via α-Oxoketene Acetals through Heteroaromatic Annelation Methodology

Abstract A new general method for substituted carbazoles 4a-x has been developed involving base induced conjugate addition-elimination sequence of indole-3-acetonitriles 1 to various α-oxoketene S,S-,O,S- and N,S-acetals 2a-x followed by cyclization of the intermediates 3 with p -toluenesulfonic acid in refluxing benzene. © 1997 Published by Elsevier Science Ltd.