CYCLODEXTRIN DERIVATIVES AS CHIRAL SELECTORS - INVESTIGATION OF THE INTERACTION WITH (R,S)-METHYL-2-CHLOROPROPIONATE BY ENANTIOSELECTIVE GAS-CHROMATOGRAPHY, NMR-SPECTROSCOPY, AND MOLECULAR-DYNAMICS SIMULATION

The greater stability of the complex of methyl (S)-2-chloropropionate ((S)-1) and the hydrophobic cyclodextrin derivative 2, is deduced from its characterization by gas chromatography and NMR spectroscopy as well as from molecular dynamics simulations of the (R,S)-1/2, (R)-1/2, and (S)-1/2 systems: on complexation the H-1 NMR signals of the (S) enantiomer undergo a downfield shift of up to DELTA-delta = 0.5 relative to those of the (R) enantiomer. Thus, cyclodextrins can be used not only for enantiomeric separations, but also as chiral shift reagents. R2 = R6 = n-pentyl, R3 = acetyl.