The synthesis of (+)-(S)-1′,4-dihydroxy-2,3′-dimethyl-1,2′-binaphthalene-5,5′,8,8′-tetrone (62) and (+)-(S)-4,5′,8′-trihydroxy-2,3′-dimethyl-1,2′-binaphthalene-1′,4′,5,8-tetrone (55), compounds which are atrop-isomeric with the naturally occurring binaphthoquinones (–)-isodiospyrin and (–)-8′-hydroxyisodiospyrin, respectively, is described. The binaphthyl linkages in these compounds were stereoselectively constructed by using oxazoline chemistry. The stereochemical assignments were based on X-ray crystal structure determination and circular dichroic spectroscopy.
The regioselectivity of the lithiation of 1,4,5,8-tetramethoxynaphthalene-2-carbaldehyde (7) with butyllithium or phenyllithium in the presence of N,N,N′-trimethylethylenediamine and the subsequent bromination of the lithiated species so generated with 1,2-dibromotetrafluoroethane were investigated. Similar investigations with butyllithium as base in the presence of N,N,N′,N′-tetramethylethylenediamine or potassium t-butoxide were carried out on 1,4,5,8-tetramethoxynaphthalene-2-methanol (14). These studies were extended to 1,5,8-trimethoxynaphthalene-3-methanol (25), 3-methoxybenzenemethanol (29) and 3,5-dimethoxybenzenemethanol (32). The X-ray crystal structure of 6-bromo-1,4,5,8-tetramethoxynaphthalene-2-methanol (17) is described.