Photoredox-Catalyzed Nitroarene C–H Alkylation Using Carboxylic Acids

Nitroarenes are indispensable building blocks in organic chemistry and are embedded in numerous pharmaceuticals. However, their direct C–H functionalization via alkylation is hindered by the strongly electron-withdrawing nature of the nitro group and its tendency to intercept radical species generated under photochemical or other reaction conditions. Here, we report a photocatalytic strategy for the direct C–H alkylation of nitroarenes using readily available carboxylic acids as alkyl radical precursors. This transformation proceeds under mild, visible-light irradiation conditions, exhibits broad functional group tolerance, and is compatible with both aromatic and aliphatic carboxylic acids. Mechanistic studies indicate a decarboxylative radical addition pathway initiated by photoexcitation of an organic photocatalyst. This method enables late-stage functionalization of complex molecules and provides a modular platform for sequential C–H diversification, thereby expanding the synthetic utility of nitroarenes for medicinal chemistry applications.