From <i>S</i>-Fluoroalkylation to Fluoroalkylation–Thiolation: Difunctionalization of Alkenes with Fluoroalkyl Phenyl Sulfones and Thiophenols Enabled by Photoredox Copper Catalysis
Xiao Lin, Zhiqiang Wei, Chuanfa Ni, Alexander D. Dilman, Jinbo Hu
Abstract
Molecules containing fluoroalkyl and arylthio groups play a pivotal role in pharmaceutical and agrochemical development. The simultaneous introduction of these functional groups through the 1,2-difunctionalization of alkenes is an efficient strategy. Fluoroalkyl phenyl sulfones serve as accessible fluoroalkyl radical precursors; however, their tendency to interact with thiophenol via the electron donor-acceptor interaction mechanism can impede the desired transformation. Through meticulous selection of solvent and base, we successfully utilized copper catalysis to facilitate an alkene-involved three-component reaction. Our work unveils a photoredox copper-catalyzed fluoroalkylation-thiolation of alkenes using various fluoroalkyl phenyl sulfones (such as perfluoroethyl, tetrafluoroethyl, trifluoromethyl, difluoromethyl, difluoroalkyl, and difluorobenzyl). The efficacy of this approach is exemplified by the synthesis of Kengreal derivatives.