SYNTHESIS OF UNSYMMETRICAL BIARYLS VIA KINETIC HIGHER-ORDER CYANOCUPRATES - SCOPE, LIMITATIONS, AND SPECTROSCOPIC INSIGHTS

Treatment of lower order arylcyanocuprates ArCu(CN)Li with 1 equiv of anaryllithium (Ar'Li) at temperatures around -125-degrees-C leads to higher order reagents Ar(Ar')Cu(CN)Li2. Upon exposure of such reagents at this temperature to ground-state molecular oxygen, good yields of the unsymmetrical biaryl Ar-Ar' can be realized. Several different types of aryl ligands have been examined, including naphthalenes, to assess the generality of this method. Spectroscopic data (C-13 NMR) have been obtained on three different cuprates at -130-degrees-C and at higher temperatures to determine if their kinetic nature, as illustrated by their synthetic chemistry, can be substantiated by physical means.