A short note on the epimerization of aldoses

It is postulated that, in the epimerization of glucose in alkaline solution catalyzed by Ca2+ ions (and other cations of similar size), the intermediate is a complex of the cation with O-1, O-2, O-3 and O-4 of the sugar and that the reaction proceeds, like the Bílik reaction, with rearrangement of the carbon chain.