Predict the product from claisen condensation of the following pair of esters.
`Ph-CH_(2)-underset(O)underset(||)(C)-OCH_(3)+Ph-underset(O)underset(||)(C)-OCH_(3)overset(EtO^(Theta))to`

Answer

To predict the product from the Claisen condensation of the given pair of esters, we will follow these steps:

### Step 1: Identify the Reactants
The two esters provided in the question are:
1. **Ethyl benzoate**: Ph-CH₂-C(=O)-OCH₃
2. **Methyl benzoate**: Ph-C(=O)-OCH₃

### Step 2: Understand the Claisen Condensation Reaction
Claisen condensation involves the reaction of two esters (or one ester and a carbonyl compound) in the presence of a strong base (like sodium ethoxide, EtO⁻) to form a β-keto ester or a β-diketone. The reaction proceeds through the formation of an enolate ion from one of the esters, which then attacks the carbonyl carbon of the other ester.

### Step 3: Form the Enolate Ion
Using sodium ethoxide (EtO⁻) as the base, it will deprotonate the α-hydrogen of the first ester (ethyl benzoate) to form an enolate ion. The structure of the enolate ion will be:
- **Enolate Ion**: Ph-CH=C(=O)-OCH₃

### Step 4: Nucleophilic Attack
The enolate ion will then act as a nucleophile and attack the carbonyl carbon of the second ester (methyl benzoate). This will lead to the formation of a tetrahedral intermediate.

### Step 5: Collapse of the Tetrahedral Intermediate
The tetrahedral intermediate will collapse, leading to the formation of the new carbon-carbon bond and the release of the methoxide ion (CH₃O⁻).

### Step 6: Final Product Formation
The final product of the Claisen condensation will be:
- **Product**: Ph-CH(CO)-OCH₃ (which is a β-keto ester)

### Summary of the Reaction
The overall reaction can be summarized as:
\[ \text{Ph-CH}_2\text{-C(=O)-OCH}_3 + \text{Ph-C(=O)-OCH}_3 \xrightarrow{\text{EtO}^-} \text{Ph-CH(CO)-OCH}_3 + \text{CH}_3\text{O}^- \]

### Final Answer
The product of the Claisen condensation of the given pair of esters is:
**Ph-CH(CO)-OCH₃** (a β-keto ester) and methoxide ion (CH₃O⁻).

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