Which of the following reactions is expected to give a fairalyt good yield of `(CH_(3))_(3)C-CH=CH_(2)?

Options

A.
B.
C.
D.

Explanation

To determine which reaction is expected to give a fairly good yield of the alkene `(CH₃)₃C-CH=CH₂`, we need to analyze the given options step by step.

### Step-by-Step Solution:

1. **Identify the Alkene Structure**:
The target alkene is `(CH₃)₃C-CH=CH₂`, which is a branched alkene with a double bond between the last two carbon atoms.

2. **Evaluate Each Option**:
We have four options (A, B, C, and D) to analyze.

- **Option A**:
- The reaction involves protonation of an alcohol followed by carbocation formation.
- The carbocation formed is a secondary carbocation, which can rearrange to a more stable tertiary carbocation.
- However, the final product after deprotonation leads to a more stable alkene, which does not match our target alkene.
- **Conclusion**: Option A does not yield the desired alkene.

- **Option B**:
- This option also involves a similar mechanism where a bromine atom leaves, forming a carbocation.
- The carbocation can rearrange to a more stable tertiary carbocation.
- The final product after deprotonation is again a more stable alkene, which is not the target alkene.
- **Conclusion**: Option B does not yield the desired alkene.

- **Option C**:
- This reaction involves a nitrogen-containing compound that can also form a carbocation.
- Similar to the previous options, the carbocation rearranges to a more stable tertiary carbocation.
- The product after deprotonation is again a more stable alkene, which does not match the target alkene.
- **Conclusion**: Option C does not yield the desired alkene.

- **Option D**:
- The reaction involves a bulky base (Me₃CO⁻) reacting with a suitable substrate.
- The bulky base abstracts a proton from the less hindered carbon, leading to the formation of the desired alkene.
- The final product after this reaction matches our target alkene `(CH₃)₃C-CH=CH₂`.
- **Conclusion**: Option D yields the desired alkene.

3. **Final Answer**:
The reaction expected to give a fairly good yield of `(CH₃)₃C-CH=CH₂` is **Option D**.