The direct introduction of a carboxylic group into an aromatic carboxylic acid has been considered difficult theoretically. Recently, the regioselective syntheses of terephthalic acid, 4,4'-biphenyldicarboxylic acid and 2,6-naphthalene-dicarboxylic acid have been achieved by the carboxylation of benzoic acid, 4-biphenylearboxylic acid and 2-naphthalenecarboxylic acid, respectively, with carbon tetrachloride and copper powder in aqueous alkali, using beta-cyclodextrin (beta-CyD) as mediator under mild conditions. The one-pot syntheses of terephthalic acid, 4,4'-biphenyldicarboxylic acid and 2,6-naphthalene-dicarboxylic acid have been attained by the carboxylation of benzene, biphenyl and naphthalene, respectively, with carbon tetrachloride and copper powder in aqueous alkali, using beta-CyD as mediator. The essential factor of the carboxylation by the use of beta-Cyl) is the inclusion complex formations of beta-CyD with aromatic hydrocarbon, beta-CyD with aromatic monocarboxylate and beta-CyD with carbon tetrachloride, respectively, in the reaction mixture. The conformations of CyD-aromatic monocarboxylate inclusion complexes in aqueous alkali have been determined by the nuclear magnetic resonance spectroscopy using H-1 homonuclear Overhauser enhancement on the rotating frame. The high selectivity is ascribed to the conformation of the beta-CyD-aromatic monocarboxylate inclusion complex. The reaction mechanism is discussed on the basis of inclusion complex formation. (c) 2007 Elsevier Ltd. All rights reserved.