Facile syntheses of symmetrical diaryliodonium salts from various arenes, with sodium metaperiodate as the coupling reagent in acidic media

An easy, inexpensive, safe, and effective preparative procedure to obtain symmetrical diaryliodonium bromides (in 17-88% crude yields) from various arenes is presented in this paper. A novel method for the in situ preparation of iodosyl sulfate (Chretien's reagent) is given. Eleven exemplary crude diaryliodonium bromides were readily oxidatively metathesized with 40% aqueous tetrafluoroboric acid and 30% aqueous hydrogen peroxide (in boiling acetone, used both as a solvent and 'halogen scavenger') to give pure diaryliodonium tetrafluoroborates in 15-85% yields.