Theoretical Study of Enantiomer Recognition of β-Butyrolactone by Acetyl Cyclodextrins

Abstract

Cyclodextrins and their derivatives are widely used in chromatographic chiral seperation. Molecular mechanics was applied to study the enantiomer recognition of a chiral model, β-butyrolactone, by several acetyl derivatives of α-and β-cyclodextrins. At 0 K, β-butyrolactone bound near the wider rim of cyclodextrin rings. The stabilization energy of the complex formation, in vacuo, was in the range of -6 to -19 kcal/mol. It was found that van der Waals interaction was the major contribution for the hostguest complex formation. From this study, per(6-O-acetyl-2,3-di-O-methyl)-β-cyclodextrin (bcd-A) and per(6-O-dichloroacetyl-2,3-di-O-methyl)-β-cyclodextrin (bcd-2Cl) were found to be good chiral selectivity reagents with enantiomer differentiation energy of 4-5 kcal/mol.