K₂S₂O₈-mediated direct C-H functionalization to synthesize quinoxalin-2(1H)-one derivatives in water

A K2S2O8-mediated direct C(sp(2))-C(sp(3)) bond formation through quinoxalin-2(1H)-ones with oxindoles has been developed. An efficient and feasible strategy for direct C-H functionalization between quinoxalin-2(1H)-ones and oxindoles based on a radical coupling reaction is presented. This methodology provides a concise protocol to obtain 3-(2-oxoindolin-3-yl)quinoxalin-2(1H)-ones in water under mild conditions in moderate to good yields.