Chiral discrimination of permethylated gluco-oligosaccharide toward amino acid ester salts

The chiral discrimination ability of permethylated glucopyrano-oligosaccharides toward amino acid 2-propyl ester hydrochlorides was evaluated using FAB mass spectrometry. In the given permethylated homo-oligosaccharides, permethylated β-cello-oligosaccharide series (II) showed remarkably higher S-selectivity toward tryptophan ester salts (Trp-O-iPr+) independent of the numbers (n) of the glucopyranose unit (n=2–5). The hexamer and heptamer of the permethylated β-malto-oligosaccharide series (I) showed the very similar enantioselectivity to permethylated α- and β-cyclodextrin.