Chiral Epoxides for Leukotriene Syntheses : A D-Xylose Approach

Characterization of SRS-A, an important mediator of asthma and other hypersensitivity processes, was not achieved until 1979 1 . It has been proposed that leukotriene A 4 (LTA 4 ) is the short-lived key biochemical intermediate which can be either converted to LTB 4 by enzymatic hydration or to LTC 4 , a precursor to LTD 4 and LTE 4 , by glutathine transfer 2 . Therefore, in order to mimic the biosynthetic pathway, LTA 4 has been the prime synthetic target 3 . A survey of the various methods described in the literature clearly shows the pivotal status of the key-synthons, methyl 7-hydroxy-5, 6-epoxyheptanoates (e.g. 4 and 6 ).