Detection of Chiral Discrimination Ability of Chiral Crown Ether by FAB Mass Spectrometry

Abstract

The detection method of chiral discrimination ability of some macrocycles toward amino acid ester hydrochlorides using FAB mass spectrometry has been explained in this paper. The FABMS enantiomer labeled (EL) guest method, which was recently proposed by Sawada et al., was a useful and facile technique to detect chiral discrimination ability of new chiral hosts. A host (H) was complexed with 1 : 1 amino acid guest mixture of an (R)-enantiomer (G_R⁺) and a deuterium labeled (S)-enantiomer (G_S-dn⁺). The enantioselectivity of the host for the guest was quantitatively estimated from the relative peak intensity (I (H-G_R)⁺/I (H-G_S-dn)⁺=IRIS) values of the two host-guest complex ion peaks at a difference of m/z=n.