The Kiliani-Fischer synthesis lengthens an aldose carbon chain by adding one carbon atom to the aldehyde end of the aldose. The result of this process is a chain lengthened sugar with a new carbon atom at the `C_1` and the former aldehyde group now at `C_(2)`. This synthesis is useful both for determining the structure of existing sugars and for synthesizing new sugars. The most common method used to shorten sugar chains is the Ruff degradation. The Ruff degradation is used mainly for structure determination and synthesis of new sugars. The Wohl degradation, an alternative to the Ruff degradation, is nearly the reverse of Kiliani-Fischer synthesis. The aldose carbonyl group is converted to the oxime, which is dehydratred by acetic anhydride to the nitrile. Cyanahydrin formation is reversible, and a basic hydrolysis allows the cyanohydrin to lose HCN. Show how Wohl degradation of D-arabinose happens.

Explanation

To demonstrate the Wohl degradation of D-arabinose, we will follow a series of steps that involve the conversion of the aldose to an oxime, followed by acylation, dehydration, and hydrolysis. Here’s a step-by-step breakdown of the process:

### Step 1: Structure of D-arabinose
D-arabinose is a five-carbon aldose sugar with the following structure:
- **Structure**:
- CH2OH
- H-C(OH)-C(OH)-C(OH)-CHO

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