Total syntheses of the sesquiterpenoids (+)-trans-dracunculifoliol and (+)-4-hydroxyoppositan-7-one

Sesquiterpenoids (+)-trans-dracuncuflifoliol (1) and (+)-4-hydroxyoppositan-7-one (2) were prepared stereoselectively from enantiomerically pure (7aR)-7a-methyl-1,2,5,6,7,7a-hexahydro-4H-inden-4-one ((-)-6), whose synthesis was described herein. Conjugate addition of the organocopper (1) reagent 10 to (-)-6, followed by epimerization of the ring junction, generated 3 of the 4 contiguous chiral centers of both natural products. (c) 2005 Elsevier Ltd. All rights reserved.