An improved method for the fluorination of arylsulfur chlorotetrafluorides to arylsulfur pentafluorides

A new method for the fluorination of arylsulfur chlorotetrafluorides to arylsulfur pentafluorides is described. The reaction is promoted by hydrogen fluoride generated from potassium hydrogen fluoride and trifluoroacetic acid which also serves as a solvent. The reaction is performed under mild conditions and uses substochiometric amounts of potassium hydrogen fluorides in certain cases. Recovery and reuse of trifluoroacetic acid was successfully demonstrated which makes this method safe, simple to use, and atom- and cost-effective.