Nitrogen-directed ortho-arylation and -heteroarylation of aromatic rings catalyzed by ruthenium complexes

The ruthenium-catalyzed direct ortho-arylation reactions of 2-phenylpyridine and 2-aryloxazolines have been successfully expanded to the direct aryl–heteroaryl coupling reactions using heteroaryl bromides. The reaction mechanism involving the RuII/RuIV intermediates is proposed from the results of the stoichiometric reaction of a divalent ruthenacycle complex of 2-phenylpyridine with bromobenzene.