β-Trifluorosulfinylesters: tuneable reagents for switchable trifluoromethylsulfinylation and C–H trifluoromethylthiolation

Abstract

β-Trifluorosulfinylesters, a family of novel reagents for direct trifluoromethylthiolation and trifluoromethylsulfinylation, were developed. The reagents were easily prepared in three steps without column purification from inexpensive commercially available starting materials. The switchable reactivity of the reagents could be precisely controlled based on different activators (base or acid) and the establishment of two activation models was studied. It was found that fluorinated sulfenate anions could be easily generated under basic reaction conditions and further trapped by electrophiles such as diaryliodonium salts. Meanwhile, fluorinated sulfonium salts, which were formed in the presence of Tf₂O from β-trifluorosulfinylesters, can serve as an electrophilic synthon for the transition-metal-free C–H trifluoromethylthiolation of electron-rich arenes and alkenes.