Efficient synthesis of pyrrolo[1,2-]quinoxalines mediated by ethyl 2-(4-nitrophenyl)azocarboxylate

The synthesis of pyrrolo[1,2-alpha]quinoxalines is of importance, because they possess a variety of biological activities, and interesting fluorescence/photophysical properties. Multifarious methods for the construction of pyrrolo[1,2-alpha]quinoxalines have been developed, but there remains no general means to exhibit broad substrate scope with high functional group tolerance under mild conditions. We report herein a practical and efficient oxidative cyclization for pyrrolo[1,2-alpha]quinoxalines using ethyl 2-(4-nitrophenyl)azocarboxylate.