Synthesis of the perfluoroacetyldiisopropylmethyl radical
摘要:
A stable trifluoroacetylperfluorodiisopropylmethyl radical has been prepared by interaction of the (alpha-fluomsulfonyloxytetrafluoroethyl)perfluorodiisopropylmethyl radical with anhydrous CsF. This reaction is the first example of a chemical transformation of a C-centered radical which is not resonance-stabilized with retention of the radical center.
beta-Fluorosulphatoperfluoroalkyl radicals (3, 7 and 8) are obtained by the reaction of fluoroolefins (HFP trimer and dimer, and perfluoro-4,4-dimethylpent-2-ene, respectively) with (FSO3)(2). The pure beta-fluorosulphatotetrafluoroethylperfluorodiisopropylmethyl radical (3) has been isolated and converted to the perfluoroacetyldiisopropylmethyl radical (4) under the action of CsF. The reaction of radicals 3, 7 and 8 with SbF5 leads to the replacement of the FSO3 group by a fluorine atom. The ability of the FSO3 group in beta-fluorosulphatoperfluoroalkyl radicals to play the role of a leaving group is explained by the stabilizing effect of the unshared electron on the adjacent carbocation centre.