A Direct Access to Thiocyano-Thioesters from Cyclic Thioacetals via Photoredox Catalysis: An Introduction of Two Functional groups in One-Pot

The cyanation of organic compounds is an important and useful process as it directly provides nitriles which in turn can be utilized for different transformations. Although, thiocyanate salt has emerged as a very mild and environmentally friendly “source of CN” alternative to toxic and metal based cyanating reagents; its synthetic utility for the cyanation is highly limited to very few types of organic compounds. We have explored the reactivity of sodium thiocyanate for directly cyanating cyclic thioacetals for accessing thiocayano-thioesters with two different functional groups in one pot using photoredox catalysis under mild reaction conditions. Based on the reactivity of thiocyanate radical, the protocol has been further extended for the direct cyanation of disulfides and diselenides to access aryl thiocyanates and aryl selenocyanate. A series of control experiments and Stern-Volmer studies have been carried out to validate the mechanistic pathways.