Synthesis and Absolute Configuration of Axially Chiral Binaphthoquinones

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.