Microwave-Enhanced Cadogan Cyclization: An Easy Access to the 2-Substituted Carbazoles and other Fused Heterocyclic Systems

A microwave-enhanced Suzuki-Miyaura cross-coupling reaction in combination with a microwave-assisted Cadogan reductive cyclization is presented as an easy access to a variety of 2-substituted carbazoles and other fused heterocyclic systems. Microwave irradiation was found very useful in minimizing the proto-deboronation issues in the cross-coupling reaction, and enhances the rate of reductive cyclization in a dramatic manner.