A one-step strategy for synthesizing -formanilide benzamide activation and oxalic acid-driven reduction.

A one-step synthetic strategy for directly converting benzamides into -formanilide derivatives has been developed using oxalic acid as a hydride source. This strategy involves the selective cleavage of the amide C-N bond through a reaction with sodium azide, generating a benzyl azide intermediate. This intermediate subsequently undergoes Curtius rearrangement to form an isocyanate species, which is then reduced by thermally decomposed oxalic acid, yielding the final -formylated product. This strategy demonstrates a broad substrate scope, including various substituted benzamides and heterocyclic amides, achieving yields of up to 95%.