The graphite-catalyzed ipso-functionalization of arylboronic acids in an aqueous medium: metal-free access to phenols, anilines, nitroarenes, and haloarenes

Abstract

An efficient, metal-free, and sustainable strategy has been described for the ipso-functionalization of phenylboronic acids using air as an oxidant in an aqueous medium.

Surface Nanoarchitectonics of Boron Nitride Nanosheets for Highly Efficient and Sustainableipso-Hydroxylation of Arylboronic Acids

“…The direct hydroxylation of aromatic compounds to its corresponding phenols is a challenging task in synthetic organic chemistry. Phenols constitute an important class of biologically active compounds owing to their antibacterial, antihyperglycemic, antitumor, antiviral, antitumor, antimutagenicity, pro-oxidant, and cardioprotective properties. , Phenols and their derivatives are commonly used in industries and companies for the synthesis of fine chemicals, pharmaceuticals, and agrochemicals. , Phenolic motifs are also present in various natural products, such as terpenoids, macrolides, quinines, alkaloids, and aryl steroids. , Due to their prevalent importance, dedicated efforts have been put forward to ease the synthesis of phenols. To date, different approaches have been utilized for the synthesis of phenolic compounds like nucleophilic substitution of aryl halides by hydroxyl group, C–H aryl ring oxidation and hydrolysis of diazonium salts, hydroxylation of aryl halides using hydroxide salts, hydroxylation of aryl halides, and so on. − However, the use of toxic solvents, homogeneous catalysts, harsh reaction conditions, and expensive metal-based catalysts, tedious reaction workups, and longer reaction time made these processes undesirable for large scale applications. , …”

Copper(II) NHC Catalyst for the Formation of Phenol from Arylboronic Acid

“…This detailed study is focused on optimizing C—O bond generation from aryl boronic acids and solvent through a CEL-like mechanism, where the resulting phenols are well-used chemical intermediates having high economic value in chemical as well as in biological applications [ 23 , 24 ]. Phenol derivatives are often value-added intermediates in the preparation of many pharmaceutical and therapeutic molecules [ 25 ]. Due to their widespread utility, many efforts have been made to advance phenol preparation, including the conversion of phenylboronic acids to phenols [ 25 , 26 ].…”

“…Phenol derivatives are often value-added intermediates in the preparation of many pharmaceutical and therapeutic molecules [ 25 ]. Due to their widespread utility, many efforts have been made to advance phenol preparation, including the conversion of phenylboronic acids to phenols [ 25 , 26 ]. Moreover, identifying conditions that favor C—O bond formation in water (and renewable solvents like methanol) also provide insight into conditions that limit C—O bond forming reactions.…”