Acyclic/cyclic perfluoroalkylamino-substituted beta-fluorosultones, R(f)(CFCF2SO2O [R(f) = (CF3)2N (I), CF2CF2CF2CF2N (II), and CF2CF2OCF2CF2N (III)], comprise a new class of compounds which can be prepared by reacting gamma-SO3 with the corresponding perfluorovinylamine at room temperature (I) or at 75-80-degrees-C for approximately 36 h. Sultone I is thermally unstable at 80-90-degrees-C and isomerizes to form (CF3)2NC(O)CF2SO2F. The reaction of II and III with fluoride ion and the formation of methyl (fluorosulfonyl)-difluoroacetate upon methanolysis support the structure where SO3 adds to the perfluorovinylamine in a reverse order as compared to fluoroolefins.