Oxidation of aldoses with bromine

Abstract
Rates of oxidation of aldoses with bromine have been reappraised and interpreted in the light of present concepts of conformation and reaction mechanism. It is suggested that differences in the rates of oxidation of the α and β anomers are largely determined by differences in the free energy required by the reactants for passing from the ground state to the complex in the transition state. Structures for the aldoses in the ground states and in the transition states are postulated, and factors affecting the energy required for reaching the transition states from the ground states are discussed. The relative rates of oxidation are in accordance with the hypothesis that each of the aldoses in the ground state has the conformation predicted by Reeves, and, in the transition state, has a conformation in which the oxygen atom of the C1-hydroxyl group lies in the plane formed by the ring oxygen atom, C1, C2, and C5. Presumably, this conformation is stabilized by resonance involving the oxygen atom of the ring.