Synthetic route for selective modification of the secondary hydroxyl face of cyclodextrins

The synthesis and characterization of O2-pertosylated cyclodextrins and per-cyclo-α-1,4-manno-2,3-epoxides is described. 1H and 13CNMR spectral analyses are given, showing the existence of strong hydrogen bonding between the tosyl S─O and the cyclodextrin C3-OH groups. Use of the 1H-NMR coupling constants has allowed molecular modelling of cyclo-α-1,4-heptamannoepoxide, confirming a preference for the gauche-trans and gauche-gauche configurations at the primary hydroxy face. Fast atom bombardment mass spectral studies suggest a preferential interaction with K+ rather than Na+ ions.