Photoinduced reduction of nitro(hetero)arenes with earth-abundant FeCl3 promoter.

The reduction of nitroaromatic compounds to aromatic amines is a crucial step in the production of pharmaceuticals, dyes, and other materials. In this study, we used the earth-abundant iron salt FeCl3 as a promoter to efficiently reduce various (hetero)aryl nitro compounds under visible light irradiation at 395 nm and room temperature. This method, with its gentle reaction conditions and wide substrate range, effectively avoids reliance on precious metals and harsh conditions common in traditional methods. Its versatility is demonstrated by its ability to reduce a broad spectrum of nitro compounds, making it a valuable tool for chemists and researchers across multiple fields. Mechanistic studies have confirmed that chlorine radicals formed through photoexcitation are the key active species responsible for reducing nitro groups to amino groups.