Visible-light-promoted direct C-H/S-H cross-coupling of quinoxalin-2(1H)-ones with thiols leading to 3-sulfenylated quinoxalin-2(1H)-ones in air

A new and efficient visible-light-mediated strategy has been developed for the synthesis of 3-sulfenylated quinoxalin-2(1H)-ones via direct C-H sulfenylation of quinoxalin-2(1H)-ones with thiols in air at room temperature. Through this photochemical reaction, various 3-sulfenylated quinoxalin-2(1H)-ones can be efficiently and conveniently obtained in excellent yields with good functional group tolerance by simple use of rhodamine B as the cheap photocatalyst and air as the green oxidant.