Absolute configurations of enantiomeric 1,2-dihydrobenzo[b]fluoranthene-trans-1,2-diols and diastereomeric 1,2,3,3a-tetrahydrobenzo[b]fluoranthene-trans-1,2-diols

Article abstract of DOI:10.1021/jo00377a022

1,2-Dihydrobenzo[b]fluoranthene-trans-1,2-diol (1) was converted by hydrogenation to two diastereomeric 1,2,3,3a-tetrahydrobenzo[b]fluoranthene-trans-1,2-diols (2a and 2e) which differed in the conformational preference of the hydroxyl groups. The diastereomeric 2a had a shorter retention time on both reversed-phase and normal-phase HPLC than 2e. Proton NMR spectral analyses indicated that the hydroxyl groups of 2a and 2e preferentially adopt quasidiaxial and quasidiequatorial conformations, respectively. The diastereomeric conformers 2a and 2e were interconvertible when they were dissolved in some organic solvents at elevated temperatures. The enaintiomers of 1, 2a, and 2e were separated by normal-phase HPLC using a chiral stationary phase (Pirkle type IA) column. The hydroxyl groups of the more strongly retained enantiomers of 1, 2a, and 2e by the chiral stationary phase have identical (1R,2R) absolute stereochemistries which were established by the exciton chirality CD method.