A Coupling of Benzamides and Donor/Acceptor Diazo Compounds To Form γ‑Lactams via Rh(III)-Catalyzed C–H Activation

The coupling of O-pivaloyl benzhydroxamic acids with donor/acceptor diazo compounds provides isoindolones in high yield. The reaction tolerates a broad range of benzhydroxamic acids and diazo compounds, including substituted 2,2,2-trifluorodiazoethanes. Mechanistic experiments suggested that C–H activation is turnover-limiting and irreversible and that insertion of the diazo compound favors electron-deficient substrates.