Question

Identify product ‘A’ in the following reaction.
\[ \text{R - C} \equiv \text{N} \xrightarrow{\text{DIBAL-H}} \xrightarrow{\text{H}_3\text{O}^+} A \]

• A. R - CONH\(_2\)
• B. R - COOH
• C. R - CHO
• D. R - CH\(_2\)NH\(_2\)

Hint:

DIBAL-H reduces nitriles to aldehydes, and hydrolysis with H\(_3\)O\(^+\) further helps in the reaction.

Answer 1

The Correct Option is C

Step 1: Understanding the reaction.
The reaction involves the reduction of a nitrile group (C≡N) using DIBAL-H (diisobutylaluminum hydride), followed by hydrolysis with H\(_3\)O\(^+\) to produce an aldehyde. The nitrile group is reduced to an aldehyde, as seen in the product R - CHO.

Step 2: Analyzing the options.
(A) R - CONH\(_2\): This is an amide, not the correct product of the reaction.
(B) R - COOH: This is a carboxylic acid, which is not formed in this reaction.
(C) R - CHO: Correct — The reduction of nitriles with DIBAL-H followed by hydrolysis forms an aldehyde.
(D) R - CH\(_2\)NH\(_2\): Incorrect — This is an amine, not an aldehyde.

Step 3: Conclusion.
The correct answer is (C) R - CHO, which is the aldehyde product formed.