A Shelf-Stable Reagent for Photocatalytic Radical Pentafluorosulfanylation of Styrene Derivatives

We have developed the first family of air- and moisture-stable pentafluorosulfanylation (SF₅) reagents. Although the SF₅ group is a bioisostere of the trifluoromethyl group (CF₃)—exhibiting even greater electronegativity and lipophilicity, attributes that have earned it the nickname "super trifluoromethyl group"—the development of shelf-stable, non-toxic, and easy-to-handle SF₅-incorporating reagents had remained elusive for over 70 years since its discovery. Our discovery enables the synthesis of per- and polyfluoroalkyl substances (PFAS)-free fluorinated compounds, offering significant advantages over traditional CF₃ analogs. These new reagents exhibit promising reactivity under photochemical conditions, efficiently facilitating the formation of novel SF₅-containing molecules. Moreover, our approach is compatible with the late-stage functionalization of complex molecules. Mechanistic studies have provided valuable insights into the underlying reaction pathways.