Influence of the nature and substitution of chiral 2,3-epoxy alcohol derivatives on the enantiomeric elution order on chiralcel OD column

A number of 2,3-epoxy alcohol derivatives (1-16), obtained either as racemates or through the Sharpless asymmetric epoxidation reaction, were studied on a Chiralcel OD column. Nearly all compounds exhibit good enantioselective resolution on this chiral support. The order of elution of enantiomers is reversed between nerol and geraniol compounds. For 2,3-epoxy alcohols bearing a remote alkoxy (or silyloxy) group, the order of the enantiomeric elution alternates with the number n (n = 1-3) of methylenic groups present between the epoxide ring and the terminal OR (R = p - BrBn or OSitBuPh₂) functionality. In the case of <i>trans</i> 2,3-epoxy alcohols for the same number n, the order of elution is reversed when changing the terminal group -OSi to -OR. The latter group greatly improves the separation of the two enantiomers.