Flavin/I2-Catalyzed Aerobic Oxidative C–H Sulfenylation of Aryl-Fused Cyclic Amines

Graphical A metal-free aerobic oxidative C–H sulfenylation of aryl-fused cyclic amines with various thiols was developed with excellent functional compatibility. While flavin I catalyzed the C–H sulfenylation of indolines to afford 3-sulfenylindoles, flavin II enabled transformations resulting in substitution at the position para to the N atom on the aryl ring to obtain 6-sulfenylquinolines. We report an aerobic oxidative C–H sulfenylation of aryl-fused cyclic amines with various thiols catalyzed by flavin/I 2 for the first time. While flavin I catalyzed the C–H sulfenylation of indolines to afford 3-sulfenylindoles, flavin II enabled transformations resulted in substitution at the position para to the N atom on the aryl ring to obtain 6-sulfenylquinolines. The advantages of this metal-free oxidative C–S coupling approach utilizing ambient oxygen as the terminal oxidant were that it was conducted under mild conditions with good atom-efficiency and excellent functional compatibility.