Manganese-Catalyzed N-Formylation of Anilines Using Oxalic Acid as CO Surrogate

Formanilides are valuable synthetic intermediates and additives in the rubber industry. Manganese-catalyzed N-formylation of aniline using (COOH)₂·2H₂O represents a significant advancement in the synthesis of formanilides. This novel approach offers a safe and efficient alternative to traditional carbon monoxide (CO) gas-based formylation reactions, addressing safety concerns and overcoming the challenges associated with handling gaseous CO. By employing (COOH)₂·2H₂O as a readily available and environmentally benign CO surrogate, this method also demonstrates the versatility of manganese catalysts in facilitating selective C–N bond formation. This study presents the first manganese-catalyzed synthesis of formanilides via the N-formylation of anilines using (COOH)₂·2H₂O, providing a range of formanilides in moderate to excellent yields.