Organocatalyzed-Aerobic Oxidation of Arylboronic Acids toward the Synthesis of Phenolic Derivatives

An effective organocatalyzed ipso-hydroxylation of arylboronic acids for the preparation of phenol derivatives has been demonstrated. The elucidated phenomenon relies on the catalytic performance of 3-nitropyridine under the influence of sub-stoichiometric quantities of KO^tBu employing aerobic conditions in DMSO solvent. This method excludes the excess usage of oxidizing agents and bases by providing a user-friendly synthetic tool for the preparation of phenols. It was acclaimed that the 3-nitropyridine acts as an oxygen transferring agent from in situ generated hydrogen peroxide to boronic acid derivatives to furnish the desired molecules. The required hydrogen peroxide was in situ generated from aerial oxygen by the KO^tBu-mediated single electron transfer process. The described process is applicable to a variety of arylboronic acids for the preparation of phenols in good yields with considerable resistance of functional moiety.