Absolute Configuration of Benzophenanthrene 5,6-Oxide and Other K-Region Derivatives

Article abstract of DOI:10.1021/jo00354a007

Synthesis of enantiomerically pure benzophenanthrene (+)-(5S,6R)- and (-)-(5R,6S)-oxides is described from diastereomerically pure (-)-(5R,6R)-trans-5-bromo-6-<(menthyloxy)acetyl>- and (+)-(5S,6S)-trans-5 bromo-6-<(menthyloxy)acetyl>-5,6-dihydrobenzophenanthrene derived from (-)-(menthyloxy)acetic acid.Configurational assignment of the enantiomeric arene oxides is based on correlation of the CD spectra of their trans-N-acetyl-L-cysteine adducts as methyl esters with the bis(-)-α-methoxy(trifluoromethyl)phenylacetate) of (+)-(5R,6R)-trans-5,6-dihydroxy-5,6-dihydrobenzophenanthrene of known absolute configuration.Separable major and minor S adducts were obtained from each arene oxide enantiomer.Structures of the major (attack at C-6) and minor (attack at C-5) adducts were established through the use of 5-deuterated arene oxide.Predominant attack (3:1) of the thiolate at C-6 of the arene oxide is consistent with PMO calculations.