In Situ Formed I^III‐Based Reagent for the Electrophilic <i>ortho</i>‐Chlorination of Phenols and Phenol Ethers: The Use of PIFA‐AlCl₃ System

Abstract

A new and in situ formed reagent generated by mixing PIFA {bis[(trifluoroacetoxy)iodobenzene]} and AlCl 3 was introduced in the organic synthesis for the direct and highly regioselective ortho ‐chlorination of phenols and phenol ethers. An efficient electrophilic chlorination for these electron‐rich arenes as well as the scope of the reaction are described herein. An easy, practical, and open‐flask reaction allowed us to introduce a chlorine atom, which is a highly important functional group in organic synthesis. The reproducibility of our method has been demonstrated on gram‐scale by carrying out the reaction in 6‐bromo‐2‐naphthol. This halogenation reaction also proceeds in excellent conditions by first preparing the iodine(III)‐based chlorinating reagent. Our new chlorinating reagent can be stored at least for two weeks at 4 °C without losing its reactivity.