Which can be cleaved by `HIO_4` ?

Options

A. `CH_3CH_2overset(O)overset(||)C"" CH_2overset(O)overset(||)C"" CH_3`
B. `CH_3"" overset(OH)overset(|)Choverset(O)overset(||)C""CH_2CH_3`
C.
D. `CH_3overset(O)overset(||)C""CH_2underset(OH)underset(|)CHCH_2overset(O)overset(||)C""CH_3`

Answer

To determine which compound can be cleaved by periodic acid (HIO₄), we need to identify if the compound contains a cis-diol structure. Periodic acid is known to cleave cis-diols and convert them into ketones. Let's analyze the given options step by step.

### Step 1: Identify the structure of each compound

1. **Option 1: CH₃CH₂C(=C)CH₂CH₃**
- This compound does not contain a cis-diol structure. It has a double bond but lacks the necessary hydroxyl groups on adjacent carbons to form a cis-diol.

2. **Option 2: CH₃COH(COOCH₂CH₃)**
- This compound can be represented as CH₃C(OH)(COOCH₂CH₃). Here, we can see that it has a hydroxyl group (OH) and a carbon chain that can form a cis-diol structure. Thus, it can be cleaved by HIO₄.

3. **Option 3: CH₃C(=C)C(=O)CH₃**
- This compound has a trans configuration due to the arrangement of the substituents around the double bond. It does not form a cis-diol, so it cannot be cleaved by HIO₄.

4. **Option 4: CH₃C(=O)CH₂C(=O)CH₃**
- This compound does not contain any hydroxyl groups that would allow it to form a cis-diol. Therefore, it cannot be cleaved by HIO₄.

### Conclusion
Based on the analysis, **Option 2 (CH₃COH(COOCH₂CH₃))** is the only compound that can be cleaved by HIO₄ due to the presence of a cis-diol structure.

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