Enantioseparation properties of (1-->6)-alpha-D-glucopyranan and (1-->6)-alpha-D-mannopyranan tris(phenylcarbamate)s as chiral stationary phases in HPLC

Synthetic polysaccharides, (1-->6)-alpha-D-glucopyranan (3a) and (1-->6)-alpha-D-mannopyranan (3b), were prepared by the cationic ring-opening polymerization of 1,6-anhydro-2,3,4-tri-O-allyl-beta-D-glucopyranose (1a) and 1,6-anhydro-2,3,4-O-6-allyl-beta-D-mannopyranose (1b), followed by the cleavage of the allyl ether linkage of 2,3,4-tri-O-allyl-(1-->6)-alpha-D-glucopyranan (2a) and 2,3,4-tri-O-allyl-(1-->6)-alpha-D-mannopyranan (2b), respectively. 2,3,4-Tris-O-(3,5-dimethylphenylcarbamoyl)- and 2,3,4-tris-O-(3,5-dichlorophenylcarbamoyl)-(1-->6)-alpha-D-glucopyranan (CSP-1 and CSP-2, respectively) and 2,3,4-tris-O-(3,5-dimethylphenylcarbamoyl)- and 2,3,4-tris-O-(3,5-dichlorophenylcarbamoyl)-(1-->6)-alpha-D-mannopyranan (CSP-3 and CSP-4, respectively) were prepared by the reaction of 3 with the corresponding 3,5-disubstituted phenylisocyanates and the chiral recognition abilities of CSP-1-4 as chiral stationary phases (CSPs) in high-performance liquid chromatography (HPLC) were evaluated. Racemic compounds such as trans-cyclopropanedicarboxylic acid dianilide (9), 1,2,2,2-tetraphenylethanol (10), flavanone (11), Tr?ger's base (12), benzoin (13), and cobalt(III) tris(acetylacetonate) (14) were efficiently resolved using CSP-1-4. For comparison among CSPs, the chiral recognition properties of the (1-->6)-alpha-D-glucopyranan CSPs were different from that of the (1-->6)-alpha-D-mannopyranan CSPs, and CSP-4 exhibited the highest chiral recognition ability among the CSPs. The resolution factors of 12 and 14 were 0.42 and 0.56 for CSP-1, 0.32 and 2.16 for CSP-2, 1.80 and 0.84 for CSP-3, and 2.31 and 8.26 for CSP-4, respectively.