METHYL (3R)-3-HYDROXYHEX-5-ENOATE AS A PRECURSOR TO CHIRAL MEVINIC ACID ANALOGS

Baker's yeast reduction of methyl 3-oxohex-5-enoate 14b provides methyl (3R)-3-hydroxyhex-5-enoate 15b with 78% enantiomeric enrichment. Subsequent seleno- and iodo-lactonization of derived hex-5-enoic acids leads to valerolactones 18, 19, 25 and 26 which are suitable for the subsequent elaboration of a variety of mevinic acid analogues. The absolute configuration of the major enantiomer produced in the initial yeast reduction was determined by correlation with natural (S)-(+)-parasorbic acid 23.