Ru(II)- or Rh(III)-Catalyzed Difunctionalization of Alkenes by Tandem Cyclization of N‑Aryl Acrylamides with Alkenes

The reaction of N-aryl acrylamides with maleimides in the presence of a ruthenium/rhodium catalyst and Cu­(OAc)2·H2O provided succinimide-substituted oxindole derivatives in good to excellent yields. In the reaction, 3,3′-disubstituted oxindoles are produced via a C–H alkylation and intramolecular oxidative cyclization sequence. The proposed mechanism was supported by competition experiments, deuterium labeling studies, and radical scavenger experiments.