Which , if any, of the following pairs of reagents could be used to prepare 2-phenyl-2-butanol ?

Options

A. `CH_(3)CH_(2)MgBr+Ph-overset(O)overset(||)(C)-CH_(3)`
B. `CH_(3)CH_(2)MgBr+C_(6)H_(5)CH_(2)overset(O)overset(||)(C)H`
C. `CH_(3)MgI + C_(6)H_(5)CH_(2)overset(O)overset(||)(C)CH_(3)`
D. `C_(6)H_(5)MgCl + CH_(3)overset(O)overset(||)(C)CH_(2)CH_(2)CH_(3)`

Explanation

To determine which pairs of reagents can be used to prepare 2-phenyl-2-butanol, we need to analyze the given reagents and their reactions step by step.

### Step 1: Identify the structure of 2-phenyl-2-butanol
2-phenyl-2-butanol has the following structure:

```
CH3
|
C - OH
|
CH
|
C6H5
```

This indicates that the compound has a butanol backbone with a phenyl group attached to the second carbon.

### Step 2: Analyze the first pair of reagents: CH3CH2MgBr and PhC(=O)CH3
1. **Reagent 1**: CH3CH2MgBr (ethyl magnesium bromide) is a Grignard reagent.
2. **Reagent 2**: PhC(=O)CH3 (acetophenone) is a ketone.

**Reaction Mechanism**:
- The Grignard reagent (CH3CH2MgBr) acts as a nucleophile and attacks the carbonyl carbon of acetophenone.
- This leads to the formation of a magnesium alkoxide intermediate.

The reaction can be summarized as follows:
1. CH3CH2MgBr + PhC(=O)CH3 → PhC(OH)(CH2CH3)MgBr
2. Hydrolysis of the intermediate will yield 2-phenyl-2-butanol.

### Conclusion for the first pair:
This pair can successfully produce 2-phenyl-2-butanol.

### Step 3: Check other pairs of reagents
You would repeat this process for the other pairs of reagents provided in the question. For each pair, identify whether they can produce the desired product through a similar mechanism.

### Final Answer:
After analyzing all pairs, the first pair (CH3CH2MgBr and PhC(=O)CH3) is confirmed to produce 2-phenyl-2-butanol.

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