Preparation of Enantiomers of 17-Epoxy Eicosapentaenoic Acis and Their 18-Hydroxy Derivatives

摘要

By the action of NBS in aq DME, dl-17-bromo-18-hydroxy EPA methyl ester 6 was prepared, which was effectively resolved by lipase PS and vinyl acetate in the presence of a thiacrown ether to give the resolved bromoacetate (7) and bromohydrin (8), each being transformed into the corresponding epoxide (3 and 4). The absolute configuration of 8 was established by the Kusumi-Moscher method. Both epoxides were treated with LDA to provide alyl alcohols (5a and b), accompanined with the formation of cyclopropyl derivatives (10a and b).