Rhodium-catalyzed formal [4 + 3] annulation reaction of N-methoxybenzamides with gem‑difluorocyclopropenes: A combination of experimental and theoretical studies

A rhodium-catalyzed [4 + 3] cycloaddition reaction between N-methoxybenzamides and gem‑difluorocyclopropenes is described. The reaction offers a mild and efficient approach towards the synthesis of fluorinated 2H-azepin-2-ones with broad substrate scope. A consecutive HOAc-assisted CN bond formation and fluorine elimination are involved as key steps for success as illustrated by detailed DFT studies.