Selective Catalytic Aerobic Photooxidation of Thioethers to Sulfoxides

A convenient visible-light-promoted oxidation of thioethers to sulfoxides was developed, utilizing Eosin Y as the photocatalyst and molecular oxygen from air as the oxidant. This photochemical protocol features good functional-group tolerance and exquisite chemoselectivity. Under the mild conditions, a wide variety of sulfides were converted into the corresponding sulfoxides in excellent yield (up to 93%). Moreover, this protocol also can easily be scaled-up to gram scale, showing good practical value.