Palladium (II)-Catalyzed Decarboxylative Cross-Dehydrogenative Coupling: Direct Synthesis of meta-Substituted Biaryls from Aromatic Acids

A palladium-catalyzed tandem process of simple aromatic acids has been achieved to afford meta-substituted biaryls in moderate to good yields. The reaction proceeds via carboxyl-directed intermolecular cross-dehydrogenative coupling and subsequent decarboxylation. The new C-C bonds in this transformation are formed in the ortho position of carboxyl and the reaction tolerates electron-rich acids. Both symmetrical and unsymmetrical meta-substituted biaryls can be directly synthesized via this method.