Scalable Preparation and Application of Ar ₂ S ⁺ -CF ₃ TfO –

S -Trifluoromethyl sulfonium salt Ph 2 S + CF 3 TfO – has emerged as a powerful reagent for trifluoromethylation. However, a scalable synthesis of this salt has not been reported to date, and its preparation traditionally relies on highly toxic benzene, which raises significant safety and environmental concerns. In this work, we first achieved a practical tens-of-gram-scale synthesis of Ph 2 S + CF 3 TfO –, and then, we realized a >100 g-scale preparation of an analogue, S -trifluoromethyl bis(4-fluorophenyl)sulfonium triflate (F-Sul). The synthesis of this salt avoids the use of benzene and streamlines the purification (no chromatography required). Comprehensive evaluation revealed that F-Sul exhibits nearly identical reactivity to Ph 2 S + CF 3 TfO – in diverse trifluoromethylation reactions. Furthermore, we demonstrated the scalability and synthetic utility of F-Sul by achieving the hundred-gram-scale synthesis of nonafluorobutyl trifluoromethyl sulfonate ( n C 4 F 9 SO 3 CF 3, TFNf), a valuable trifluoromethoxylation reagent and an electrolyte additive for lithium-ion batteries.