Water‐Mediated C−H Cyanation of Quinoxalin‐2(1H)‐ones and Quinoxalines Under Visible‐Light Conditions

Abstract

AbstractRegioselective cyanation of quinoxalin‐2(1H)‐ones and quinoxalines with acetone cyanohydrin under aqueous aerobic visible‐light conditions at room temperature is described. Acetone cyanohydrin is utilized as a safe source for cyanation. In both cases, good functional group tolerance was observed with very good to quantitative yields of products under metal/base/ligand‐free conditions. Several control experiments revealed that, water and oxygen from air are crucial for the efficiency of the present transformation. These reactions proceed through a radical pathway as confirmed by radical scavengers. To validate the feasibility of the process for commercial syntheses, three products were synthesized at gram scale under the optimized conditions. The conversion of cyanated products into corresponding amides and acid was also performed and the pure products were obtained without column chromatographic separation.