Rh(III)-Catalyzed C–H Activation/Cyclization of Benzamides and Diazonaphthalen-2(1H)‑ones for Synthesis of Lactones

A Rh­(III)-catalyzed C–H activation/cyclization of benzamides and diazonaphthalen-2­(1H)-ones for synthesis of lactones has been developed. In the presence of Rh­(III) catalysis, the benzamides would form rhodacycle species and could be trapped by diazonaphthalen-2­(1H)-ones for arylation, and the following intramolecular lactonization would rapidly furnish the products. Thus, the diazonaphthalen-2­(1H)-ones were first revealed as a lactonization component in Rh­(III)-catalysis, while the kinetic isotope effect study was conducted and a plausible reaction mechanism was proposed.