Metal-Catalyzed Approaches toward the Oxindole Core
Austin D. Marchese, Egor M. Larin, Bijan Mirabi, Mark Lautens
Abstract
)-X bond, followed by a migratory insertion, yielding a neopentyl species amenable to a variety of subsequent functionalizations. From this reactive neopentyl metal species, we have reported C-X reductive eliminations, anionic capture cascade reactions, and intramolecular C-H functionalization processes. The second section of this Account summarizes our group's findings on 1,2-insertions of a metal-nucleophile species across an unsaturation, generating a reactive organometallic intermediate; subsequent reactions with tethered electrophiles form the desired heterocyclic core. We have explored a wide array of transition metal-catalyzed strategies using this approach, including rhodium-catalyzed conjugate additions, an asymmetric copper-catalyzed borylcupration, and a palladium(II)-catalyzed chloropalladation protocol. The final section of this Account details the use of dual-metal catalysis to perform a cyclization through a C-H functionalization-allylation domino reaction. Throughout this Account, we provide details of mechanistic studies that better enabled our understanding of the domino processes.Overall, our group has developed methods exploiting the unique reactivity of palladium, nickel, copper, rhodium, and ruthenium catalysts to develop methods toward a wide array of oxindole scaffolds. On the basis of the utility, diversity, and applicability of the strategies developed, we believe that they will prove to be highly useful in the syntheses of other important targets and inspire further development and mechanistic understanding of various metal-catalyzed processes.