The oxidative cross-coupling of substituted 2-naphthols. Part II: Sensitivity as a mechanistic probe

Article abstract of DOI:10.1016/S0040-4020(01)88319-8

Mechanistic study of Cu(II)-mediated coupling revealed that the model reaction between 2-naphthol and 3-carbomethoxy 2-naphthol can be controlled to give either the cross-coupled product (4) or a non-selective/approximately 1:1/mixture of the cross- and homo-coupled products (4) and (5), respectively, the alternative homo-product (3) being virtually absent in both instances. The copper/ligand ratio has been found to be the main controlling factor and operation of two active copper species differing greatly in selectivity as well as reactivity has been suggested. Plausible model of a binuclear Cu(II) complex explaining the preferential cross-coupling has been devised and possible relevance to the oxidative polymerization of 2,6-dimethylphenol has been considered.