Visible Light Photoredox Activation of Sulfonyl Chlorides: Applications in Organic Synthesis

Since the seminal studies from the groups of MacMillan, Stephenson and Yoon, visible light (400-700 nm) photoredox catalysis has been established as a powerful strategy to facilitate activation of organic molecules and invention of novel synthetic methodologies. Indeed, recent days, this protocol enables the syntheses of diversely functionalized organic molecules such as coerulescines, pseudotabersonines, drugs, agro chemicals, etc. Generally, activation of the redox-active functional groups of the radical precursors including diazonium salts, iodoniumsalts, sulfoniumsalts, phosphate esters, amines and sulfonyl chlorides is achieved via single-electron transfer from a photocatalyst excited by visible light irradiation sources. To date, some important reviews are available that summarize the visible light photoredox catalyses of various classes of organic compounds. To the best of our knowledge, however, there is still no review article exclusively discourses about the visible light induced productions and applications of radical species of sulfonyl chlorides (AASO(2)Cl, AA=alkyl/aryl). Therefore, in this review, we provide an overview on the visible light assisted procedures employed for the production of radical intermediates from sulfonyl chlorides. In addition, here we account the applications of these radical species in the syntheses of bi(hetero)aryls, difluoromethyl lactones, difluoromethyl pyrrolidines, polycyclic aromatic compounds, sulfones, trifluoromethyl (hetero)aryls, alpha-trifluoromethyl ketones and so on.