JEE Main · 2024 · 09 Apr 2024 · Shift 2 · Aldehydes Ketones and Carboxylic Acids

Grignard reagents react preferentially with the more electrophilic ester carbonyl over the nitrile group under these conditions. Excess CH${}_3$MgBr adds twice to the ester group ($-{\text{CO}}_2{\text{CH}}_3$), first giving a ketone (after loss of methoxide) and then a second addition giving, after aqueous acidic workup, a tertiary alcohol bearing two methyl groups: $-{\text{C(CH}}_3{)}_2\text{OH}$. The nitrile group is left intact under these conditions.

The major product therefore retains the –CN group with the ester carbon converted to $-{\text{C(CH}}_3{)}_2\text{OH}$, corresponding to option (2).