Indoles Oxidative Ring-Opening/Cyclization Cascade with the 1,2-Diaminoarenes: Direct Synthesis of 2-Aryl-3-(2-aminoaryl)quinoxalines

A mild oxidative sequential tandem reaction wasdeveloped to rapidly generate 2-aryl-3-(2-aminoaryl) quinoxalines.This method exploited 2-substituted indoles as substrate to formquinoxalines in a one-pot reaction. The key to this tandem reactionwas the formation of 3-iodoindoles, which underwent Kornblum-type oxidation with DMSO to generate active imine 2-substitued3H-indol-3-ones. The active imines were captured in situ by 1,2-diaminobenzenes to construct diverse quinoxalines. Thetransformation can be accomplished at room temperature with excellent functional group tolerance

Automated summary

A mild oxidative sequential tandem reaction was developed for the rapid synthesis of diverse 2-aryl-3-(2-aminoaryl) quinoxalines. This method utilized 2-substituted indoles as substrates to form quinoxalines in a one-pot reaction. The key step in this tandem reaction was the formation of 3-iodoindoles, which were oxidized with DMSO to generate active imine 2-substitued 3H-indol-3-ones. The active imines were then captured in situ by 1,2-diaminobenzenes to construct diverse quinoxalines. This transformation could be conducted at room temperature and exhibited excellent tolerance towards various functional groups.