Enantioseparation of chiral epoxides using four new cyclodextrin derivatives as chiral stationary phases of capillary gas chromatography

Four new cyclodextrin derivatives (CDs), 2,6-di-O-benzyl-3-O-heptanonyl-β-cyclodextrin, 2,6-di-O-benzyl-3-O-octanonyl-β-cyclodextrin, 2,3-di-O-benzyl-6-O-heptanonyl-β-cyclodextrin, and 2,3-di-O-benzyl-6-O-octanonyl-β-cyclodextrin, were synthesized and used as chiral stationary phases for capillary gas chromatography (CGC). The four CDs can be divided into two groups by different substitution position of acyl groups in CD. It was found that both CDs with acyl groups in 6-position of CD and CDs with acyl groups in 3-position of CD possessed enantioselectivity to chiral epoxides though more baseline resolving were obtained on CDs with acyl groups in 3-position of CD than on CDs with acyl groups in 6-position of CD. On these CDs, enantiomers of chiral epoxides were successfully separated, and enantiomer excesses (e.e.%) of some chiral epoxides were also determined.