Synthesis of thioethers, arenes and arylated benzoxazoles by transformation of the C(aryl)–C bond of aryl alcohols

Abstract

Transformation of aryl alcohols into high-value functionalized aromatic compounds by selective cleavage and functionalization of the C(aryl)-C(OH) bond is of crucial importance, but very challenging by far. Herein, for the first time, we report a novel and versatile strategy for activation and functionalization of C(aryl)-C(OH) bonds by the cooperation of oxygenation and decarboxylative functionalization. A diverse range of aryl alcohol substrates were employed as arylation reagents via the cleavage of C(aryl)-C(OH) bonds and effectively converted into corresponding thioether, arene, and arylated benzoxazole products in excellent yields, in a Cu based catalytic system using O 2 as the oxidant. This study offers a new way for aryl alcohol conversion and potentially offers a new opportunity to produce high-value functionalized aromatics from renewable feedstocks such as lignin which features abundant C(aryl)-C(OH) bonds in its linkages.

Decarboxylation‐Initiated Intermolecular Carbon‐Heteroatom Bond Formation

“…Han et al. found that benzyl alcohols could be used as alternative arylation sources [301] . Under a similar Cu/Phen catalytic system, the alcohol substrate is in situ oxidized to the corresponding aromatic acid, which is the actual substrate of decarboxylative thioetherification reactions with diaryl disulfides.…”

Catalytic Conversion of Lignin into Valuable Chemicals: Full Utilization of Aromatic Nuclei and Side Chains

“…Furthermore, we pioneered a novel, versatile approach involving oxygenation and decarboxylative functionalization for activating and functionalizing C aryl –C­(OH) bonds. A diverse range of aryl alcohol substrates underwent effective C aryl –C­(OH) bond activation, transforming into arene, thioether, and arylated benzoxazole products with remarkable yields with Cu-based catalysts …”

Recent Metal-Catalyzed Methods for Thioether Synthesis

“…103 Similar reaction conditions were applied to convert benzylic alcohols to thioethers via oxidative cleavage of the CAr-C(OH) bond and subsequent decarboxylation. 104 Other reported achievements include couplings of alkynyl carboxylic acids, 105 methylthiolations using DMSO, 106 and syntheses of perfluoroalkyl thioethers. 107…”

“…cleavage of the C Ar -C(OH) bond and subsequent decarboxylation. 104 Other reported achievements include couplings of alkynyl carboxylic acids, 105 methylthiolations using DMSO, 106 and syntheses of perfluoroalkyl thioethers. 107 Scheme 26 Cu-catalyzed decarboxylative coupling of benzoic acids 102 The approach towards thioethers via decarbonylation and decarboxylation is promising, also due to the availability of carboxylic acid derivatives.…”