Which of the following methods would not serve to prepare 1-phenylpropan -2-ol.

Options

A. Addition of benzyl grignard reagent to ethanal
B. Addition of phenyllithium to methyloxirane
C. Addition of methyl grignard reagent to phenyl acetaldehyde.
D. Addition of phenyl magnesium bromide with ethanal.

Explanation

To determine which method would not serve to prepare 1-phenylpropan-2-ol, we need to analyze each of the given options.

### Step-by-Step Solution:

1. **Understanding the Target Compound**:
- The target compound is 1-phenylpropan-2-ol, which has the structure:
\[ \text{C}_6\text{H}_5\text{CH(CH}_3\text{)OH} \]
- This indicates that we need a phenyl group (C6H5) attached to a carbon that is also attached to a hydroxyl (-OH) group, and that carbon must be connected to another carbon (the propan part).

2. **Analyzing the First Option**:
- **Benzyl Grignard Reagent**: This reagent can be represented as C6H5CH2MgBr. When it reacts with a carbonyl compound (like acetone), it can form the desired alcohol after hydrolysis.
- The reaction would yield 1-phenylpropan-2-ol.
- **Conclusion**: This method works.

3. **Analyzing the Second Option**:
- **Addition of Phenyl Lithium to Methyl Oxyrene**:
- Phenyl lithium (C6H5Li) can add to methyl oxyrene (C6H5OCH3), resulting in a compound that can be hydrolyzed to form 1-phenylpropan-2-ol.
- **Conclusion**: This method works.

4. **Analyzing the Third Option**:
- **Addition of Methyl Grignard Reagent to Phenyl Acetaldehyde**:
- Methyl Grignard (CH3MgBr) will react with phenyl acetaldehyde (C6H5CHO) to form a secondary alcohol after hydrolysis.
- The product will be 1-phenylpropan-2-ol.
- **Conclusion**: This method works.

5. **Analyzing the Fourth Option**:
- **Addition of Phenyl Magnesium Bromide with Ethanol**:
- Phenyl magnesium bromide (C6H5MgBr) is a Grignard reagent. If it reacts with ethanol, it would not form the desired product. Instead, it would lead to an unstable intermediate and likely yield a different alcohol (like 1-phenylethanol).
- **Conclusion**: This method does NOT work.

### Final Answer:
The method that would not serve to prepare 1-phenylpropan-2-ol is **Option D: Addition of Phenyl Magnesium Bromide with Ethanol**.

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