SELECTIVE CROSS-COUPLING OF 2-NAPHTHOL AND 2-NAPHTHYLAMINE DERIVATIVES - A FACILE SYNTHESIS OF 2,2',3-TRISUBSTITUTED AND 2,2',3,3'-TETRASUBSTITUTED 1,1'-BINAPHTHYLS

The novel 1,1'-binaphthyls with OH and/or NHR (R=H or Ph) groups in the 2,2'-positions and with additional methoxycarbonyl group(s) in the 3- or 3,3'-positions (13-18) have been synthesized from their respective precursors 1-5 by the CuCl2/t-BuNH(2)-mediated oxidative cross-coupling. In most cases, the chemoselectivity was good, and the cross-coupled products 11-18 were obtained in fair to excellent yields. Binaphthyls 6-10, resulting from the self-coupling, and carbazoles 19-23 have been identified as byproducts. Ab initio calculations and electrochemical measurements have been employed to account for the observed selectivity.