Efficient Synthesis of Spirooxindole Pyrrolones by a Rhodium(III)‐Catalyzed C−H Activation/Carbene Insertion/Lossen Rearrangement Sequence

Abstract A rhodium(III)‐catalyzed domino annulation of simple olefins with diazo oxindoles to give spirooxindole pyrrolone products is described. This reaction can be formally viewed as the result of an anomalous tandem C−H activation, carbene insertion, Lossen rearrangement, and a nucleophilic addition process. The potential utility of this reaction was further demonstrated by the late‐stage diversification of drug molecules.