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 an aryllithium (Ar'Li) at temperatures around -125 o C leads to higher order reagents Ar(Ar')Cu(CN)Li 2 . 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 ( 13 C NMR) have been obtained on three different cuprates at -130 o C and at higher temperatures to determine if their kinetic nature, as illustrated by their synthetic chemistry, can be substantiated by physical means