Chapter 23.11, Problem 23.33P

The Wohl degradation, an alternative to the Ruff degradation, is nearly the reverse of the Kiliani—Fischer synthesis. The aldose carbonyl group is converted to the oxime, which is dehydrated by acetic anhydride to the nitrile (a cyanohydrin). Cyanohydrin formation is reversible, and a basic hydrolysis allows the cyanohydrin to lose HCN. Using the following sequence of reagents, give equations for the individual reactions in the Wohl degradation of D-arabinose to D-erythrose. Mechanisms are not required.

1. a. hydroxylamine hydrochloride
2. b. acetic anhydride
3. c. ⁻OH, H₂O