Which of the following conversion is known as Stefen's reduction?

Options

A.
B.
C.
D.

Answer

**Step-by-Step Text Solution:**

1. **Understanding Steffen's Reduction**: Steffen's reduction is a chemical reaction where cyanides and nitriles are converted into aldehydes. This process requires specific reagents, namely tin(II) chloride (SnCl2) and dilute hydrochloric acid (HCl), followed by the addition of water.

2. **Identifying the Reactants**: In this reaction, the starting materials are cyanides (which have the functional group C≡N) or nitriles. The goal is to reduce these compounds to aldehydes (RCHO).

3. **Analyzing the Options**:
- **Option 1**: LiAlH4 is a strong reducing agent that reduces aldehydes, ketones, and esters to alcohols, but it does not correspond to Steffen's reduction. Therefore, this option is eliminated.
- **Option 2**: SnCl2 and HCl are the correct reagents for Steffen's reduction, making this option a strong candidate for the correct answer.
- **Option 3**: The presence of sodium in ethanol and water suggests a different reaction, not Steffen's reduction. This option is eliminated.
- **Option 4**: Acyl chloride with Pd/BaSO4 and H2 refers to Rosenmund's reduction, which is also not Steffen's reduction. This option is eliminated.

4. **Conclusion**: Based on the analysis of the options, the correct conversion known as Steffen's reduction is the one involving **SnCl2 and HCl**.

5. **Mechanism of Steffen's Reduction**: The mechanism involves the formation of an imine intermediate when a cyanide reacts with SnCl2 and HCl. Upon heating and subsequent addition of water, the imine is hydrolyzed to yield the corresponding aldehyde and ammonium chloride.

**Final Answer**: The conversion known as Steffen's reduction is the one that uses **SnCl2 and dilute HCl** to convert cyanides and nitriles into aldehydes.

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