Synthesis of maleimide fused benzocarbazoles and imidazo[1,2-a]pyridines via rhodium(iii)-catalyzed [4+2] oxidative cycloaddition

In this paper, an efficient and sustainable synthesis of the synthetically and pharmaceutically significant maleimide-fused benzocarbazoles/imidazo[1,2-a]pyridines from the reaction of 2-arylindoles/2-arylimidazo[1,2-a]pyridines with maleimides through rhodium-catalyzed oxidative [4 + 2] annulation is presented. This method features easily obtainable substrates, high atom-efficiency and good functional group tolerance. Notably, by using this method a bioactive agent was smoothly synthesized in an excellent yield.