Establishing the Trifluoromethylthio Radical Donating Abilities of Electrophilic SCF₃-Transfer Reagents

Abstract

The recent recognition of the novel application of a few traditional electrophilic trifluoromethylthiolating reagents as SCF₃ radical sources offers a remarkable new opportunity for the development of radical trifluoromethylthiolation reactions. Herein, the first trifluoromethylthio radical donating ability (Tt^•DA) scale of electrophilic SCF₃-transfer reagents has been developed. This scale is based on Y-SCF₃ bond dissociation energies, which were obtained by density functional calculations (M06-2X). Single electron transfer is revealed to exhibit a substantial Y-SCF₃ bond-weakening effect, thus significantly facilitating the SCF₃ radical (^•SCF₃) release. The results may aid in future novel radical SCF₃-transfer reagent design and new reaction development.