Structure and Absolute Configuration of Kessanol and 8-epi-Kessanol

The sesqutierpenoid alcohols, kessanol and 8-epi-kessanol, isolated from certain kinds of Japanese valerian, have been shown to be 2-deoxykessyl glycol (I;R=H) and 2-deoxy-8-epi-kessyl glycol (III;R=H), respectively, by physicochemical studies of the alcohols and their oxidation products, kessan-8-one(II). The mixture of the wwo alcohols (I and III;R=H) has been synthesized from kessyl glycol (IV;R=H, R'=H). The configuration of the hydroxyl at C-8 as being α in kessanol and β in 8-epi-kessanol has been confirmed by application of the dissymmetry rule.