Enantioselective synthesis of methyl (5Z,8S)-8,9-epoxynon-5-enoate, an eicosanoid synthon

A six-step synthesis of methyl (5Z,8S)-8,9-epoxynon-5-enoate, a known synthon of constanolactones and hepoxilins, from 5-hexynoic ester was developed. The enantiomeric purity of the synthon was attained by S-enantiodirected dihydroxylation of a double bond in the intermediate methyl non-8-en-5-ynoate with subsequent enantioselective hydrolysis of the epoxide group in the admixture of the minor R-enantiomer. Dedicated to Academician V. A. Tartakovsky on his 75th birthday. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1586–1592, August, 2007.