Tischenko reaction yields ester in the presence of catalyst which is `:`

Options

A. `LiAlH_(4)`
B. N-bromosuccinimide
C. `Al(OC_(2)H_(5))_(3)`
D. `Zn-Hg//HCl`

Answer

To solve the question regarding the Tischenko reaction and the catalyst used, we will break down the process step by step.

### Step-by-Step Solution:

1. **Understanding the Tischenko Reaction**:
- The Tischenko reaction involves the reaction of aldehydes in the presence of a catalyst to yield esters. It typically results in the formation of an ester from two molecules of an aldehyde.

2. **Identifying the Catalyst**:
- The catalyst used in the Tischenko reaction is aluminum alkoxide, specifically triethylaluminum (Al(OC2H5)3). This compound is essential for facilitating the reaction.

3. **Mechanism of the Reaction**:
- The reaction begins with the coordination of the aldehyde to the aluminum atom of the aluminum alkoxide catalyst.
- The aluminum has empty 3d orbitals which can accept electron density from the oxygen of the aldehyde, forming a complex.

4. **Formation of the Ester**:
- As the reaction proceeds, the aldehyde undergoes a series of steps including the formation of a cyclic intermediate, leading to the rearrangement and ultimately the formation of the ester.
- The final product is an ester, which is characterized by the presence of the ester functional group (–COOR).

5. **Conclusion**:
- The Tischenko reaction yields an ester in the presence of triethylaluminum (Al(OC2H5)3) as the catalyst.

### Final Answer:
The catalyst used in the Tischenko reaction is **triethylaluminum (Al(OC2H5)3)**.

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