TFAA-Catalyzed Annulation Synthesis of Spiro Pyrrolo[1,2-a]quinoxaline Derivatives from 1-(2-Aminophenyl)pyrroles and Benzoquinones/Ketones.

A metal-free trifluorosulfonate anhydride (TFAA)-catalyzed strategy for the synthesis of spiro pyrrolo[1,2-a]quinoxalines from 1-(2-aminophenyl)pyrroles and benzoquinones/ketones has been developed. With this general method, spiro pyrrolo[1,2-a]quinoxalines have been accessed via nucleophilic addition and cyclization. This reaction exhibits good functional group tolerance, and a wide range of products are obtained in moderate to good yields.