Iron-Catalyzed Hydrogen Transfer Reduction of Nitroarenes with Alcohols: Synthesis of Imines and Aza Heterocycles

A straightforward and selective reduction of nitroarenes with various alcohols was efficiently developed using an iron catalyst via a hydrogen transfer methodology. This protocol led specifically to imines in 30-91% yields, with a good functional group tolerance. Noticeably, starting from o-nitroaniline derivatives, in the presence of alcohols, benzimidazoles can be obtained in 64-72% yields when the reaction was performed with an additional oxidant, DDQ, and quinoxalines were prepared from 1,2-diols in 28-96% yields. This methodology, unprecedented at iron for imines, also provides a sustainable alternative for the preparation of quinoxalines and benzimidazoles.

Automated summary

A novel method for the selective reduction of nitroarenes with various alcohols using an iron catalyst via hydrogen transfer has been efficiently developed. This methodology leads to imines with good functional group tolerance in yields ranging from 30-91%, and also provides a sustainable alternative for the preparation of quinoxalines and benzimidazoles.