Chiroptical and conformational properties of ketohexoses

Abstract

Circular dichroism of acyclic forms of D-fructose, L-sorbose, D-tagatose, and four deoxy derivatives of D-fructose has been interpreted from the point of view of the equilibrium of rotamers around the bond of the chromophore and chiral residue of the molecule. The conformational equilibrium manifested by the double-sign dichroic curve changes with constitutional, solvation, and temperature conditions. It can be characterized as a syn ⇌ anti equilibrium according to mutual orientation of the carbonyl and vicinal hydroxyl groups.