`PhCOOC_(2)H_(5)+C_(2)H_(5)-COOC_(2)H_(5) overset(NaNH_(2))(to)` Number of condensated products (including stereoisomer)

Explanation

To solve the problem of determining the number of condensed products (including stereoisomers) formed from the reaction of two esters in the presence of a base, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Reactants**:
The reactants are two esters:
- Ethyl benzoate (PhCOOC₂H₅)
- Ethyl acetate (C₂H₅COOC₂H₅)

2. **Understand the Reaction Type**:
The reaction involves a condensation reaction facilitated by a base (NaNH₂). This will lead to the formation of beta-keto esters.

3. **Mechanism Overview**:
The base will deprotonate the acidic hydrogen from one of the esters, generating a nucleophilic species (a carbanion). This carbanion will then attack the carbonyl carbon of the other ester, leading to the formation of a beta-keto ester.

4. **Formation of the First Condensed Product**:
- When the carbanion generated from ethyl acetate attacks the carbonyl carbon of ethyl benzoate, the first beta-keto ester is formed.
- The structure of the product will be:
\[ CH₃C(=O)C(=O)OEt \]
- This product has a chiral center at the alpha carbon, making it optically active.

5. **Stereoisomers from the First Product**:
- Since the product has one chiral center, it can exist as two stereoisomers (D and L forms).

6. **Formation of the Second Condensed Product**:
- The carbanion can also react with itself (the same ester), leading to another beta-keto ester.
- The structure of this product will be:
\[ CH₃C(=O)C(=O)OEt \]
- This product also has a chiral center, making it optically active.

7. **Stereoisomers from the Second Product**:
- Similar to the first product, this second product also has one chiral center, which means it can also exist as two stereoisomers (D and L forms).

8. **Total Count of Condensed Products**:
- From the first product, we have 2 stereoisomers.
- From the second product, we also have 2 stereoisomers.
- Therefore, the total number of condensed products (including stereoisomers) is:
\[ 2 + 2 = 4 \]

### Final Answer:
The total number of condensed products, including stereoisomers, is **4**.

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