For the preparation of the key synthetic intermediate I of leukotriene A4, some asym. epoxidn. methods for 7-chiral 5-heptenoic acid derivatives have been evaluated. The cis-olefin II prepared from D-gluceraldehyde could be selectively hydroxylactonized. The mesylate of the 6-hydroxy compound III was treated with NaOMe to afford the desired (5S,6R)-epoxide IV. Deprotection of the diol group and cleavage with sodium periodate in one pot gave I.

Key words: INTERMEDIATE, EPOXIDATION REACTION, ESTERIFICATION, CARBOXYLIC ACID ESTER, STEREOSELECTIVITY, EPOXIDE, EPOXIDE, ALDEHYDES, HEPTANOIC ACID P, EICOSATETRAENOIC ACID P