Question

Which reagent is used in the Stephen reaction to reduce nitriles to imines?

• A. \(LiAlH_4\)
• B. \(SnCl_2/HCl\)
• C. \(NaBH_4\)
• D. \(Zn/HCl\)

Hint:

Remember: The Stephen reaction converts nitriles into aldehydes through an intermediate imine using \(SnCl_2/HCl\) as the reducing agent.

Answer 1

The Correct Option is B

The Stephen reaction is a well-known chemical reaction that involves the reduction of nitriles to aldehydes using a specific reducing agent, which in turn forms an imine intermediate. The reagent used in this reaction is crucial for the transformation.

1. \(Nitriles\): Compounds containing the \(-C \equiv N\) group.
2. An \(imine\) is an intermediate formed during the reduction process in the Stephen reaction.
3. The correct reagent for this reduction, according to the question, is \(SnCl_2\) in the presence of \(HCl\).

Explanation:

• \(SnCl_2/HCl\): In the Stephen reaction, stannous chloride (\(SnCl_2\)) acts as a reducing agent in the presence of hydrochloric acid (\(HCl\)). This combination effectively reduces nitriles to imines, which can further undergo hydrolysis to form aldehydes.
• \(LiAlH_4\), \(NaBH_4\), and \(Zn/HCl\): These reagents are also reducing agents but are not specifically used for the Stephen reaction mechanism.

Thus, the reagent \(SnCl_2/HCl\) is specifically used for reducing nitriles to imines as part of the Stephen reaction, which can be concluded as the correct answer.