Asymmetric Oxidative Coupling of 2-Naphthols Catalyzed by Chiral Copper–Amino Acid-Derived Ligand Complexes

We developed a [Cu(CH₃CN)₄]⁺BF₄^-/air-mediated asymmetric coupling method using novel l-amino acid-derived aminopyridine-amide ligands to access various C₂/C₁-symmetric BINOLs. This represents the first application of amide-containing ligands in copper-catalyzed asymmetric oxidative coupling of 2-naphthols. Notably, the efficient one-pot integration of the transesterification and coupling processes establishes a novel strategy for synthesizing ester-functionalized BINOLs. The formation of highly active Cu₂O₃ oxides was detected from Cu(I) species under single-crystal X-ray diffraction analysis and is the key determinant for the stereoselective control of the catalytic cycle. Moreover, this method also enables the efficient synthesis of racemic binaphtholone compounds.