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

We report an aerobic oxidative C–H sulfenylation of aryl‐fused cyclic amines with various thiols catalyzed by flavin/I2 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. 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.