Wohl degradation

The Wohl degradation in carbohydrate chemistry is a chain contraction method for aldoses The classic example is the conversion of glucose to arabinose as shown below.



In one modification, d-glucose is converted to the glucose oxime by reaction with hydroxylamine and sodium methoxide. In the second step the pentaacetyl glycononitrile is formed by reaction with acetic anhydride in acetic acid with sodium acetate. In this reaction strep the oxime is converted into the nitrile with simultaneous conversion of all the alcohol groups to acetate groups.

In the final step sodium methoxide in methanol is added on which the nitrile group is split off as sodium cyanide with formation of a new formyl group.