Photodriven Iron-Catalyzed C(sp ² )–N Coupling of <i>α-</i> Keto Acids with Nitroarenes for the Synthesis of Aryl Amides

Herein, we report a photodriven C(sp²)-N coupling reaction between nitroarenes as the nitrogen source and α-keto acids via a ligand-to-metal iron charge transfer (Fe-LMCT) mechanism, utilizing bulk chemicals like nitroarenes as the nitrogen source. This transformation proceeds without the need for reductants, oxidants, or additives under mild conditions that accommodate a broad range of nitroarenes and α-keto acids, demonstrating a wide substrate scope and offering a new strategy for the efficient construction of C(sp²)-N bonds. Detailed mechanistic studies suggest that a plausible reaction pathway has been proposed, where the iron catalyst and α-keto acid form an iron-carboxylate complex in situ, generating a sp²-carbon radical upon light irradiation. The formation of a nitrosobenzene intermediate from nitrobenzene under light conditions is critical for the success of C(sp²)-N coupling.