Harnessing (Phenylsulfonyl)difluoromethyl Sulfonium Salt: A Radical Approach to Photoredox-Catalyzed Functionalization of Unsaturated Compounds with the PhSO2CF2 Group

A photoredox-catalyzed, modular method for the synthesis of versatile (phenylsulfonyl)-difluoromethylated compounds is presented. The key step in this transformation is the light-driven generation of a fluoroalkyl radical from our in-house-designed (phenylsulfonyl)-difluoromethyl sulfonium salt. Tuning the reactivity of this fluorinated sulfonium salt under photocatalysis provided an efficient tool for the direct functionalization of readily available olefins. Notably, the photocatalyzed difunctionalization of alkenes, as well as three- or four-component reactions, were studied, providing efficient access to an array of difluoroalkylated linear or cyclic products. Mechanistic studies have been conducted to provide a better understanding of the reaction mechanism for the synthesis of (phenylsulfonyl)-difluoromethylated alkenes. Exploring the reactivity of the (phenylsulfonyl)-difluoromethyl salt under photocatalysis has led to a straightforward, versatile strategyakin to a "Swiss army knife"for accessing a wide range of (phenylsulfonyl)-difluoromethyl-containing molecules.