Abstract: Contrary to implications in the literature, polyfluorovinyl ethers have been shown to form unstable sultones with sul-fur trioxide. Near 25 OC these sultones isomerize easily to P- carbonylsulfonate esters. A fluorovinyl diether was found to lead preferentially to cyclic sulfate, a convenient precursor to a perfluoro a-diketone. Mechanisms for these transformations are proposed. These reactions offer superior routes to the two classes of ...