H2O2 in WERSA: an efficient green protocol for ipso-hydroxylation of aryl/heteroarylboronic acid

A mild, green, economic and efficient protocol has been developed for ipso-hydroxylation of aryl/heteroarylboronic acids to phenols using 30% aqueous H2O2 as an oxidant and WERSA (water extract of rice straw ashes) as a neat reaction medium. All reactions were carried out without using metal, ligand, activator or hazardous organic solvent with excellent yield within a very short reaction time at room temperature. Therefore, this appears to be the cleanest and greenest alternative protocol for ipso-hydroxylation of aryl/heteroarylboronic acids.