Acetate groups as probes of the stereochemistry of carbohydrates: a vibrational circular dichroism study

Vibrational absorption and circular dichroism spectra of five different mon osaccharide pentaacetates were measured. These spectra were found to be dom inated by the contributions from the acetate groups. In the carbonyl region , alpha- and beta-D-glucose pentaacetates do not show measurable vibrationa l circular dichroism (VCD), but alpha- and beta-D-galactose pentaacetates a nd alpha-D-mannose pentaacetate show significant VCD, with mannose pentaace tate giving opposite signs to those of alpha- and beta-D-galactose pentaace tates. These observed features are interpreted to reflect the orientation o f carbonyl groups around the carbohydrate ring. (C) 1999 Elsevier Science L td. All rights reserved.