10-I-3 Iodanes based on the benziodoxole structure and bearing a perfluoroalkyl group on iodine � typically trifluoromethyl � have been extensively used in electrophilic perfluoroalkylation reactions of a variety of substrates, such as e.g. (hetero)arenes, olefins, enols, secondary and primary phosphines, thiols, azoles, etc. The reactivity of these reagents may be influenced by Br�nsted and Lewis acids as well as by transition-metal ions or complexes, in order to achieve chemoselective transformations. Thus, protonation of 1-trifluoromethyl-1,3-dihydro-3,3-dimethyl-1,2-benziodoxole (1 ) leads to an isolable species with a pKa of 5.04 that is more reactive than the parent species. Analogously, 1-trifluoromethyl-1,2-benziodoxol-3-(1H)-one (2 ) coordinates to Zn(II) ions and is thereby able to O-trifluoromethylate alkanols. Protonation of 2  is also a key preequilibrium in the formation of trifluoromethyl sulfonates from sulfonic acids and this reaction shows an inverse equilibrium deuterium isotope effect. Structure/reactivity relationships have been used to elucidate mechanistic features of several reactions involving reagents 1  and 2 . Selected examples will be presented.

Structural and mechanistic aspects of hypervalent iodine reagent for perfluoroalkylation

248th National Meeting (2014)

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