Which of the following compounds will give tertiary butanol as the major product when treated with excess of MeMgBr?

Options

A.
B.
C.
D. `CH_(3)-overset(O)overset(||)C-NH_(2)`

Answer

To determine which of the given compounds will yield tertiary butanol as the major product when treated with excess methyl magnesium bromide (MeMgBr), we need to analyze the reactivity of each compound with the Grignard reagent.

### Step-by-Step Solution:

1. **Identify the Compounds**:
We have several compounds to analyze. For this solution, let's denote them as Compound 1, Compound 2, Compound 3, and Compound 4.

2. **Understanding Grignard Reagent Reaction**:
The Grignard reagent (MeMgBr) is a strong nucleophile. It will attack electrophilic centers, particularly carbonyl groups (C=O). The reaction typically leads to the formation of an alcohol after hydrolysis.

3. **Analyze Compound 1**:
- Compound 1 is a benzaldehyde derivative (C6H5CHO).
- When treated with MeMgBr, the nucleophilic methyl group attacks the carbonyl carbon, forming an alkoxide intermediate.
- The alkoxide can then undergo protonation to yield a secondary alcohol (not tertiary butanol).

4. **Analyze Compound 2**:
- Compound 2 is an ester (C6H5COOCH3).
- The reaction with MeMgBr will lead to the formation of a tertiary alcohol after two successive nucleophilic attacks.
- The first attack forms a ketone, and the second attack leads to the formation of tertiary butanol.

5. **Analyze Compound 3**:
- Compound 3 is a ketone (C6H5C(=O)CH3).
- The reaction with MeMgBr will also lead to the formation of tertiary butanol after the nucleophilic attack and subsequent hydrolysis.

6. **Analyze Compound 4**:
- Compound 4 has an amine (C6H5C(=O)NH2).
- The nucleophilic attack by MeMgBr will not lead to the formation of tertiary butanol, as the amine is not a good leaving group.

7. **Conclusion**:
- From the analysis, Compound 2 and Compound 3 will yield tertiary butanol as the major product when treated with excess MeMgBr.
- Therefore, the correct options are Compound 2 and Compound 3.

### Final Answer:
The compounds that will give tertiary butanol as the major product when treated with excess MeMgBr are **Compound 2 and Compound 3**.