The first practical synthesis and isolation of trifluoromethylthiophosphonium salts were achieved from an unprecedented reaction of allyl trifluoromethyl sulfoxide and phosphines in the presence of TMSOTf through Mislow-Evans-type rearrangement. The resulting trifluoromethylthio triphenylphosphonium salt exhibited versatile reactivities with a variety of nucleophiles, electrophiles, carboxylic acids, and unactivated alkenes.

Comprehensive Summary

This article described an unprecedented synthesis of trifluoromethylthiophosphonium salts from allyl trifluoromethyl sulfoxide and phosphines in the presence of trimethylsilyl trifluoromethanesulfonate (TMSOTf) through Mislow-Evans-type rearrangement. The resulting trifluoromethylthiophosphonium salts were firstly isolated and fully characterized. These fluoroalkylphosphonium salts, as exemplified by trifluoromethylthio triphenylphosphonium salt (6a), exhibited unique and versatile reaction with nucleophiles and deoxygenative trifluoromethylthiolation reaction of carboxylic acids. Furthermore, the photoredox catalytic tunable radical hydrotrifluoromethylation and hydrotrifluoromethythiolation of unactivated alkenes with 6a was successfully developed.