Copper-catalyzed reductive cross-coupling reaction of aryl chlorides and aryl bromides

Abstract

In this work, We report a Cu-catalyzed reductive cross-electrophile coupling that enables the direct formation of C-C bonds between aryl chlorides and aryl bromides under reductive conditions. In contrast to classical cross-coupling reactions that rely on preformed organometallic reagents, this method employs a Cu(OTFA)₂ and (4R,4'R)-2,2'-methylenebis[4,5-dihydro-4-(phenylmethyl)-Oxazole (BOX) catalytic system in combination with MeMgBr as the reductant.The catalytic cycle is initiated by the formation of a Cu-BOX complex and proceeds through fundamental steps involving oxidative addition, transmetalation, and reductive elimination. Modulation of the electronic properties of the copper center by the chiral BOX ligand enables efficient and selective cross-reductive coupling between two electrophilic aryl partners.This transformation operates under mild reaction conditions and exhibits high chemoselectivity along with broad substrate scope. The corresponding biaryl products are obtained in yields of up to 93%. This study provides a new and sustainable approach for the construction of C(sp²)-C(sp²) bonds and expands the synthetic toolbox for accessing structurally diverse biaryl motifs relevant to materials science and pharmaceutical research.