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.