Question

The reagent used in the Stephen reaction is:

• A. \(\mathrm{Pd-BaSO_4 + H_2}\)
• B. \(\mathrm{SnCl_2 + HCl}\)
• C. \(\mathrm{AlH(i-Bu)_2 + H_2O}\)
• D. DIBAL-H \(+\mathrm{H_2O}\)

Hint:

Stephen Reduction: Nitrile \(\rightarrow\) Aldehyde using \(\mathrm{SnCl_2/HCl}\). Rosenmund Reduction: Acid chloride \(\rightarrow\) Aldehyde using \(\mathrm{Pd/BaSO_4}\).

Answer 1

The Correct Option is B

Step 1: Recall the Stephen reaction.
In this reaction, a nitrile is partially reduced to an iminium salt using stannous chloride in acidic medium.

Step 2: Hydrolysis of the intermediate.
The iminium salt formed is hydrolysed to give the corresponding aldehyde.

Step 3: Identify the reagent.
The characteristic reagent used is: \[ {\mathrm{SnCl_2 + HCl}} \]

Step 4: Eliminate the remaining options.
Option (A) corresponds to Rosenmund reduction. Options (C) and (D) correspond to DIBAL-H reductions. Therefore option (B) is correct.