Synthesis of (+)-ginnol, a type R(long)-CH(OH)-R'(long) alcohol, by an asymmetric β,γ-unsaturated ester→γ-butyrolactone conversion

Article abstract of DOI:10.1016/S0040-4020(98)00688-7

An enantioselective synthesis of (+)-ginnol (17) illustrates how Sharpless' asymmetric dihydroxylation may be used for the asymmetric synthesis of monoalcohols. The dihydroxylation was perfomed with AD mix α and the unsaturated ester trans-9. The resulting lactone cis-13 was dehydrated giving butenolide 13 (96.2% ee) from where we proceeded to the title compound 17 in three steps. Butenolide 13 showed 88-94%ee when ester trans-9 contained cis-isomer due to too forcing reaction condition on the way to the precursor acids trans- and cis-7.