Self-condensation of iodosylbenzene. Formation of a (p-phenylene) type of bisiodine(III) reagents

Article abstract of DOI:10.1016/0040-4020(95)00280-L

Reaction of iodosylbenzene (PhIO) with H₂SO₄ was reexamined. When PhIO was treated with excess H₂SO₄, followed by reaction with aromatic substrates such as benzene, toluene, and bromobenzene, aryl(phenyl)(p-phenylene)bisiodonium salts were obtained in good to high yields. In stead of aromatic substrates, treatment of the reagent prepared from PhIO and H₂SO₄ with KI afforded (p-iodophenyl)(phenyl)iodonium iodide. Similarly, the (p-phenylene) type of bisiodonium salts were obtained with a fairly strong acid (-H(o) > 8.0) such as chlorosulfonic acid and trifluoromethanesulfonic acid. These results indicate that the reaction of PhIO with a strong acid gives rise to the formation of (p-phenylene)bisiodine(III) type of reagent, which leads to (p-iodophenyl)(phenyl)iodonium salt by the decomposition or to (p-phenylene)bis(aryliodonium) salts by the reaction with aromatic substrates. The self-condensation of iodosylbenzene to (p-phenylene)bisiodine(III) type of reagents is discussed.