ABSTRACT
The synthesis of biaryl products from aryl halides continues to draw attention from both academic and industrial investigators as these compounds have found applications in wide variety of pharmaceuticals and specialty chemicals. Recent publications in the patent literature have demonstrated a new use for substituted biaryls as precursors for phosphine ligands utilized in transition metal catalyzed processes. The formation of substituted biaryl compounds from aryl halides has been the subject of much investigation for many years. The reductive dimerization reaction promoted by external secondary reducing agents represents only one of several approaches to maintaining the nickel catalyst in the active, lower oxidation state. The bipyridine ligand was found to be essential in the reaction mixture to attain high yields. A search was undertaken to see if other nitrogen containing ligands could be substituted for the bipyridine ligand.
