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

Abstract

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 α-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.