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

Options

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

Explanation

To determine which of the given compounds will yield a tertiary alcohol upon reaction with `CH₃MgBr` (a Grignard reagent), we will analyze each option step by step.

### Step-by-Step Solution:

1. **Understanding the Grignard Reagent**:
Grignard reagents, such as `CH₃MgBr`, are nucleophiles that can react with electrophilic carbon atoms, typically in carbonyl compounds or compounds with good leaving groups.

2. **Option A: C₆H₅CHO (Benzaldehyde)**:
- When `C₆H₅CHO` reacts with `CH₃MgBr`, the nucleophilic `CH₃` attacks the carbonyl carbon.
- The reaction produces `C₆H₅CH(OH)CH₃`, which is a secondary alcohol (not tertiary).
- **Conclusion**: This option does not yield a tertiary alcohol.

3. **Option B: C₂H₅C(=O)OCH₃ (Ethyl Methoxyacetate)**:
- Here, the methoxy group (`OCH₃`) is a good leaving group.
- The Grignard reagent will first attack the carbonyl carbon, leading to the formation of an intermediate.
- The intermediate can then lose the methoxy group, yielding a ketone.
- A second reaction with `CH₃MgBr` will yield `C₂H₅C(CH₃)₂OH`, which is a tertiary alcohol.
- **Conclusion**: This option yields a tertiary alcohol.

4. **Option C: C₂H₅C(=O)OH (Ethyl Hydroxyacetate)**:
- In this case, the hydroxyl group is a poor leaving group.
- The Grignard reagent will not effectively react with this compound because the `OH` group does not leave easily.
- The product formed will not be a tertiary alcohol.
- **Conclusion**: This option does not yield a tertiary alcohol.

5. **Option D: CH₃CH(OH)CH₂CH₃ (Isopropanol)**:
- The Grignard reagent will attack the carbon adjacent to the `OH` group.
- This reaction will produce `CH₃C(CH₃)(OH)CH₂CH₃`, which is a secondary alcohol.
- **Conclusion**: This option does not yield a tertiary alcohol.

### Final Answer:
Based on the analysis, the compound that will give a tertiary alcohol upon reaction with `CH₃MgBr` is **Option B: C₂H₅C(=O)OCH₃**.

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