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Preparation of the Enantiomers of 19-Epoxy Docosahexaenoic Acids and Their 4-Hydroxy Derivatives.-The preparation of epoxide (V), lactone (VII), and 4-hydroxy derivative (IX) (and their enantiomers) is based on the resolution of ester (II) by lipase PS and vinyl acetate in the presence of thiacrown ether TCT to give resolved ester (II) and acetate (IV), which are each converted by similar procedures to the above compounds. -(KATO,

Preparation of Optically Active 15-Epoxy-α-linolenic Acids and TheirAnti-Rice Blast Fungus Activities.-NBS-Bromination of α-linolenic acid methyl ester (I) in aqueous solution gives two bromohydrins (II) and (III). The latter can be easily resolved by lipase-catalyzed acetylation. Conversion of both resolved compounds to the corresponding target epoxy acid ester (VI) and comparison with the natural material shows that the natural epoxide has the configuration of (VI) with 10% e.e. Interestingly, the activity of the unnatural epoxide concerning the inhibition of spore germination of the rice blast fungus is stronger than the natural isomer. -(KATO, TADAHIRO