Abstract
Highly reactive hypervalent organoiodine reagents were prepared from iodosylbenzene (PhIO) or iodobenzene diacetate [PhIO(OAc)2] by using the activating agents such trifluoromethanesulfonic acid or the anhydride. The reagents [PhIO-TfOH] and [PhI(OAc)2-2 TfOH] showed a high reactivity toward unsaturated substrates : aromatics, alkenes, and alkynes. Reaction of PhIO with double the molar quantity of TfOH gave a (p-phenylene) bisiodine (III) reagent, 1-[(hydroxy)(trifyloxy)iodo]-4-[(phenyl)(trifyloxy)iodo] benzene, which also indicated an excellent reactivity toward unsaturated substrates. ο-Iodosylbenzoic acid was activated by TfOH to afford a reactive iodine (III) reagent. The high reactivity of the present organoiodine (III) reagents was useful in organic synthesis, specially preparation of functionalized iodonium salts. The prepared alkynyliodonium salts and [ο-(trimethylsilyl)phenyl] iodonium salts were found to be especially accessible to organic synthesis.
