Synthesis of Chiral and Modifiable Hexahydroxydiphenoyl Compounds

A reliable method for synthesizing each enantiomer of the hexahydroxydiphenoyl (HHDP) compounds has been developed. The synthesis involved atropselective construction of the aryl–aryl bond of the HHDP compounds. This construction relied on the CuCl2·n-BuNH2-mediated intramolecular coupling of bis­(4-O-benzylgallate) on two simple chiral auxiliaries, both of which were derived from l-(+)-tartaric acid. The coupling reaction realized complete or near-perfect atropselectivity. The two auxiliaries induced opposite axial chirality despite their identical origin. The diastereoselectivities of these couplings were probably controlled kinetically. Modifications of the free phenolic hydroxy groups and the carbonyl groups in the resulting HHDP compounds demonstrated the potential derivatization of a wide variety of HHDP analogues.