Enediol theory

Scheme I illustrates the interesting position of n-fructose in the sugar series, and the widely differing products obtained in the past few years by treatment with acid or alkali. Only intermediates and end products are given the reaction conditions are described in the text. Emphasis is placed on D-fructose because of its abundant occurrence in Nature and its rapid conversion into other isomers. The 1,2-enediol (c) and its ionized form (f) have central positions, indispensable to explaining hexose interconversions in alkaline media. The enediolate ion was mentioned for the first time during work on the saccharinic acids, and, in 1944, IsbeU used this same mechanism during development of his electron-displacement theory. ...

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