unit (S)-7 gave bicyclic ketones 8 and 9, which were easily converted into vinyl sulfide 11. Stereoselective construction of the A-ring was achieved by the second [3+2] cycloaddition reaction of the BC-ring unit. New methods for introduction of the oxygen functional groups to the triquinane skeleton were also developed for the last stages of the total synthesis. Thus, the C7 hydroxyl group was introduced
The first totalsynthesis of (±)-coriolin from the tricyclo 6-4-5-fused ring photo-adduct through the key tricyclo 5-5-5-fused ring intermediate, 7,8,11 - trihydroxy - 1,4,4 - trimethyltricyclo[6.3.0.02,6]undecan - 3 - one, is described.