Rhodium(III)-Catalyzed Redox-Neutral 1,1-Cyclization of N-Methoxy Benzamides with Maleimides via C-H/N-H/N-O Activation: Detailed Mechanistic Investigation.

An Rh(III)-catalyzed 1,1-cyclization of N-methoxy benzamides with maleimides providing isoindolinone spirosuccinimides through N-H/C-H/N-O bond activation is described. The detailed mechanistic investigation including isolation of key metalacycle intermediate, deuterium labeling studies, and DFT calculations were performed. The computational study reveals that the AcOH that formed in the reaction medium plays a key role in the N-OMe bond cleavage and the oxidation of Rh(I) to Rh(III).