Iodine(III)-Mediated, Controlled Di- or Monoiodination of Phenols

An oxidative procedure for the electrophilic iodination of phenols was developed by using iodosylbenzene as a non-toxic iodine(III)-based oxidant and ammonium iodide as a cheap iodine atom source. A totally controlled mono-iodination was achieved by buffering the reaction medium with K3PO4. This protocol proceeds with short reaction times, at mild tempera-tures, in an open flask and generally with high yields. Gram scale reactions, as well as the scope of this protocol, were ex-plored with electron-rich and electron-poor phenols as well as heterocycles. Quantum chemistry calculations revealed PhII(OH)·NH3 to be the most plausible iodinating active species as a reactive “ I+ ” synthon. In light of the relevance of the iodoarene moiety, we present herein a practical, efficient and simple procedure with a broad functional group scope that al-lows access to the iodoarene core unit.