Thermal N-O bond heterolysis of TEMPO-CF₂CF₃ towards trifluoroacetylation of alcohols and amines

We herein report the gram-scale synthesis of TEMPO-CF2CF3, which belongs to the class of perfluoroalkoxyamines, and its unique properties and reactivities towards nucleophiles under thermal conditions. When heated in acetonitrile, TEMPO-CF2CF3 undergoes unusual N-O bond heterolytic cleavage, instead of C-O bond homolytic cleavage that is common to other alkoxyamines. The resulting pentafluoroethoxy anion proceeds through alpha-F elimination generating trifluoroacetyl fluoride that can be trapped by a nucleophile such as alcohol or amine. Overall, TEMPO-CF2CF3 acts as an effective trifluoroacetylating reagent in neutral conditions. Computational studies were employed to provide insights on this compound's propensity for N-O bond heterolysis under mild thermal conditions.