Which of the following compounds on reaction with `CH_(3)MgBr` will give a tertairy alcohol ?

Options

A. `C_(6)H_(5)CHO`
B. `C_(2)H_(5)CO_(2)CH_(3)`
C. `C_(2)H_(5)COOH`
D.

Answer

To solve the question of which compound will yield a tertiary alcohol when reacted with `CH₃MgBr` (methyl magnesium bromide), we need to analyze each compound provided in the options.

### Step-by-Step Solution:

1. **Understanding Grignard Reagents**:
- Grignard reagents like `CH₃MgBr` act as strong nucleophiles. The methyl group (`CH₃⁻`) will attack electron-deficient carbon atoms in the compounds.

2. **Analyzing Compound A**:
- Compound A is a benzaldehyde (C₆H₅CHO). The carbonyl carbon (C=O) is electron-deficient.
- When `CH₃⁻` attacks the carbonyl carbon, it forms a secondary alcohol after protonation.
- **Conclusion**: Compound A gives a secondary alcohol, not a tertiary alcohol.

3. **Analyzing Compound B**:
- Compound B is an ester (RCOOR').
- The nucleophile `CH₃⁻` will attack the carbonyl carbon, leading to the formation of a ketone intermediate.
- The remaining alkoxy group (R') will leave, and then another `CH₃⁻` can attack the ketone, resulting in a tertiary alcohol after protonation.
- **Conclusion**: Compound B gives a tertiary alcohol.

4. **Analyzing Compound C**:
- Compound C is propanoic acid (CH₃COOH).
- The Grignard reagent will act as a base and deprotonate the acid, resulting in the formation of methane gas (CH₄) and not an alcohol.
- **Conclusion**: Compound C does not yield an alcohol.

5. **Analyzing Compound D**:
- Compound D is an epoxide.
- The `CH₃⁻` can attack either carbon of the epoxide, leading to the opening of the ring and forming a secondary alcohol after protonation.
- **Conclusion**: Compound D gives a secondary alcohol.

### Final Answer:
- The compound that will yield a tertiary alcohol upon reaction with `CH₃MgBr` is **Compound B** (the ester).