Metal Catalyst‐Free Oxidative Cleavage of Aryl C(OH)−C Bonds

KOtBu was found to be able to transform aryl alcohols and ketones to the desired benzoic acids without any other additives using 4 MPa O₂ in mesitylene. All aryl C(OH)−C bond in substrates with either electron-donating or electron-withdrawing groups could be transformed to the according benzoic acids in moderate to excellent yields. All findings indicated that the oxidation of aryl secondary C(OH)−C bonds might proceed through a radical mechanism.

Abstract

A simple and efficient protocol for oxidative cleavage of aryl C(OH)−C bonds to acids was reported. In this protocol, KOtBu was found to be able to transform aryl alcohols and ketones to the desired benzoic acids without any other additives using 4 MPa O₂ in mesitylene. Substrates with either electron-donating or electron-withdrawing groups could be transformed to the according benzoic acids in moderate to excellent yield. All these findings indicated that this oxidation of aryl secondary C(OH)−C bonds might proceed through a radical mechanism. And the represent lignin dimer model compound was successfully transformed to the benzoic acid, which indicated this protocol might has the potential to transform nature lignin.

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