`?underset(2.H_(2)O)overset(1.Delta//DIBAL-H)(to)CH_(3)-CH=CH-CH_(2)-CH_(2)-CH_3`

Options

A. `CH_(3)(CH_(2))_(4)CN`
B. `CH_(3)(CH_(2))_(5)NH_(2)`
C. `CH_(3)-CH=CH-CH_(2)-CH_(2)-CHO`
D. `CH_(3)(CH_(2))_(3)-CH_(2)-CHO`

Answer

To solve the question, we need to identify the correct starting material that will react with DIBAL-H (Diisobutylaluminum hydride) and water (H₂O) to yield the specified product, which is a hydrocarbon chain with 6 carbon atoms. The product is CH₃-CH=CH-CH₂-CH₂-CH₃.

### Step-by-Step Solution:

1. **Identify the Product Structure**:
The product is CH₃-CH=CH-CH₂-CH₂-CH₃, which is a 6-carbon alkene. The presence of the double bond indicates that the starting material must be an unsaturated aldehyde.

2. **Determine the Required Functional Group**:
Since we are using DIBAL-H, which is a reducing agent, we need to start with an unsaturated aldehyde. The aldehyde will be reduced to an alkane without affecting the double bond.

3. **Construct the Unsaturated Aldehyde**:
To create a 6-carbon chain with an aldehyde functional group, we can represent the aldehyde as:
- CH₃-CH=CH-CH₂-CHO
This structure has 6 carbons (5 from the chain and 1 from the aldehyde) and a double bond between the second and third carbons.

4. **Apply the Reaction**:
When DIBAL-H is used on the unsaturated aldehyde, it will reduce the aldehyde group (CHO) to a primary alcohol (CH₂OH) and subsequently, upon hydrolysis with water, it will yield the corresponding alkane:
- CH₃-CH=CH-CH₂-CH₂-CH₃ (the desired product).

5. **Final Product Confirmation**:
The final product after the reaction will be CH₃-CH=CH-CH₂-CH₂-CH₃, confirming that we have successfully converted the unsaturated aldehyde to the desired alkene without affecting the existing double bond.