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

Abstract

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 (AASO2Cl, 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, α‐trifluoromethyl ketones and so on.

Photocatalysis with organic dyes: facile access to reactive intermediates for synthesis

“…Sulfonyl radicals show a good reactivity with π-systems, allowing the synthesis of nonsymmetrical sulfones [172]. However, they are also prone to fragmentations, resulting in the desulfonylation of the substrate and the generation of the corresponding C-centered radical.…”

“…The SET oxidation of sulfinic acids and sulfinates for the generation of sulfonyl radicals has been thoroughly explored over the past decades [172]. These oxidations occur under mildly oxidative conditions, and eosin Y (OD13) stands out as an efficient photocatalyst for these steps [175][176][177].…”

Visible Light as the Key for the Formation of Carbon–Sulfur Bonds in Sulfones, Thioethers, and Sulfonamides: An Update

“…Radical intermediates formation from sulfonyl chlorides has been extensively reviewed by Natarajan. 30 Nevertheless, two photo-mediated protocols to obtain sulfonyl chlorides deserve to be cited. In 2015, Reiser reported an unprecedented reaction using alkenes as the starting materials to synthetize βtrifluoromethylsulfonyl chlorides 58 (Scheme 20a).…”

Metal‐Free Visible‐Light Photocatalytic Tandem Radical Addition–Cyclization Strategy for the Synthesis of Sulfonyl‐Containing Isoquinolinediones

“…Visible‐light photoredox catalysis provides a powerful and versatile tool for the formation of free radical species . The precursors which are currently capable of producing sulfonyl radicals include sulfinic acids, sodium sulfinates, sulfonyl chlorides, sulfonyl hydrazides, SO 2 and so on . Sodium sulfinates are stable, non‐irritating and commercially available at low cost when used as a source of sulfonyl radicals in photoredox reactions, which has attracted our interest.…”