Resolution of enantiomers using sugar-carrying polyisocyanides as chiral stationary phases for HPLC

3,5-Dimethylphenylcarbamate derivatives of alpha-/beta-glucose and alpha-/beta-galactose-carrying helical poly(phenyl isocyanide)s were used as chiral stationary phases (CSPs) for HPLC to estimate their chiral recognition abilities. CD spectroscopy suggested that the helix sense in these rigid helical polymers may be regulated by the chirality of the alpha- or beta-anomeric center of the sugar moieties. Some 10 different types of racemates with functional groups were completely or partially resolved depending on the stereostructure of the pendant sugars. The enhanced chiral recognition ability is attributable to the three-dimensionally regulated sugar arrays along the helical backbone; that is, the CSP of the a-glucose-carrying helical poly(phenyl isocyanide) exhibited more effective enantioseparation than that of the corresponding flexible poly(N-phenylacrylamide). The CSPs of the galactose-carrying poly(phenyl isocyanide)s showed the resolving ability for broader racemates than those of the glucose-type poly(phenyl isocyanide)s. Especially, the CSP of the a-galactose-carrying poly(phenyl isocyanide) separated the largest number of racemates.