Baker's yeast mediated enantioselective synthesis of the bisabolene sesquiterpenes (+)-epijuvabione and (-)-juvabione

Fermenting baker's yeast converts the unsaturated aldehydes 7 and 11 into the saturated alcohols 8 and 12, respectively. The microbial saturation of the double bond proceeds in high chemical yields and the stereoselectivity of the reduction is strongly influenced by the E:Z ratio of the substrate. Enantiopure 8 and 12 are chiral building blocks for the synthesis of bisabolene sesquiterpenes and their usefulness is shown in the preparation of (+)-epijuvabione 1 and (-)-juvabione 3.