The major product of the following reaction is
Correct Answer :
Solution :
The correct option is Option 1.
Step-by-Step Explanation:
1. Analysis of the Reactant and Reagents:
The starting material shown in the image (image_0.webp) is 4-oxo-4-phenylbutanenitrile:
This compound contains two distinct electrophilic functional groups:
(a) A ketone group () adjacent to the phenyl ring.
(b) A nitrile group () at the terminal position.
The reaction utilizes excess methylmagnesium bromide (), which is a strong nucleophile (source of ).
2. Reaction at the Ketone Carbonyl Group:
Ketones are highly electrophilic and react readily with Grignard reagents. One equivalent of attacks the ketone carbonyl carbon:
3. Reaction at the Nitrile Group:
Because the Grignard reagent is in excess, a second equivalent reacts with the nitrile group (). The nucleophilic methyl group attacks the cyano carbon, forming an imine magnesium salt:
4. Acidic Hydrolysis:
Upon adding aqueous acid ():
• The magnesium alkoxide intermediate is protonated to form a tertiary alcohol ().
• The imine magnesium salt is hydrolyzed to yield a methyl ketone ().
This matches the structure shown in Option 1 (image_1.webp).
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