Formal asymmetric syntheses of (-)-aphanorphine and (-)-eptazocine were done, utilizing asymmetric nitroolefination reaction of alpha-methyl-delta-valerolactone and a new aromatization of Diels-Alder adducts of chiral nitroolefins with the Danishefsky's diene.
NODE, MANABU;HAO, XIAO-JIANG;FUJI, KAORU, CHEM. LETT.,(1991) N, C. 57-60