Oxidative Coupling of 2-Naphthols and 1-Naphthylamines Using I ₂ /O ₂ Reagent

A facile and simple method has been developed for the synthesis of derivatives of 1,1'-bi-2-naphthols (BINOL) and [1,1'-binaphthalene]-4,4'-diamine (naphthidines) by oxidative homocoupling of 2-naphthols and <i>N</i>-substituted-1-naphthylamines using I₂/O₂ as an oxidant in dichloromethane (DCM) solvent to obtain 63-95% yields. This method works in the presence of I₂/O₂ as the oxidant and does not require a metal catalyst. The radical cation mechanism was proposed by considering the formation of radical cation intermediates, which were detected by electron paramagnetic resonance spectroscopy.