Rongalite-Promoted One-Pot Reductive Cyclization Strategy for the Construction of Pyrrolo[1,2-α]quinoxalines from 1-(2-Nitrophenyl)pyrroles

Abstract

A transition-metal-free strategy for the synthesis of pyrrolo[1,2-α]quinoxalines and 7-methylindolo[1,2-α]quinoxaline from 1-(2-nitrophenyl)-1H-pyrrole or 3-methyl-1-(2-nitrophenyl)-1H-indole using rongalite have been developed. In this transformation, rongalite serves a dual function, acting as both a reducing agent and a one-carbon (C1) synthon. The method offers an alternative approach to C–N bond formation. Furthermore, to investigate the reaction mechanism, several control experiments were performed, including radical scavenger studies, formaldehyde detection experiments, and reduction studies. The method is readily scalable and enables further modification.