First asymmetric total syntheses and determination of absolute configurations of (+)-eudesmadiene-12,6-olide and (+)-frullanolide.

The first asymmetric total syntheses of sesquiterpene lactones (+)-eudesmadiene-12,6-olide (1) and (+)-frullanolide (2) have been accomplished from 4-bromo-2-methoxyphenol (5) in 12 and 13 synthetic steps, respectively, and the absolute configurations of these two natural products were determined.