Rh(III)-Catalyzed Divergent Ring Remodeling of Oxindole with Diazo Compounds via Amide and C–H Bond Activation

An efficient and versatile Rh(III)-catalyzed divergent
ring-remodeling
strategy that transforms readily accessible oxindoles using suitable
diazo compounds into highly substituted indoles and unsymmetrically
2,6-dialkylated anilines via amide bond activation and subsequent
C–H bond activation is reported. This unified platform enables
rapid scaffold diversification, including effective late-stage modification
of complex substrates. Mechanistic investigations, supported by control
experiments, indicate a pathway involving Rh(III)-catalyzed oxindole
solvolysis, formation of cyclometalated species, metal–carbene
formation, migratory insertion, protodemetalation, and final intramolecular
dehydration of the resulting enol–amine intermediates.