VIBRATIONAL RAMAN OPTICAL-ACTIVITY OF KETOSE MONOSACCHARIDES

The vibrational Raman optical activity (ROA) spectra of the four ketos e sugars D-fructose, L-sorbose, D-tagatose and D-psicose in aqueous so lution, which have been measured in backscattering in the range approx imate to 250-1500 cm(-1), are reported. These results are combined wit h those from a previous ROA study of aldose and pentose sugars in an a ttempt to establish new vibrational assignments and to verify old ones . The high information content of these spectra provides a new perspec tive on all the central features of monosaccharide stereochemistry inc luding dominant anomeric configuration, ring conformation, exocyclic C H2OH group conformation and relative disposition of the hydroxyl group s around the ring.