K2S2O8-mediated direct C–H heteroarylation/hydroxylation of indolin-2-ones with quinoxalin-2(1H)-ones

Abstract

Herein, a K₂S₂O₈-mediated direct heteroarylation and hydroxylation reaction between quinoxalin-2(1H)-ones with a C(sp²)–H bond and indolin-2-ones with a C(sp³)–H bond via an oxidative cross-coupling reaction has been reported. We have successfully established a feasible and concise reaction system that represents the first example of free-radical-promoted heteroarylation and hydroxylation reaction on the C-3 position of oxindole. A series of 3-substituted 3-hydroxyoxindoles are obtained in 0–83% yield using this methodology.