Ethyl 3-oxobutanoate is treated with 1 equiv of CH3MgBr in dry ether at 0 degC, followed by a quick H3O+ work-up. The result is

the starting ester is recovered and methane is evolved

ethyl 3-hydroxy-3-methylbutanoate

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JEE Advanced levelSingle correct optionDifficulty 3 of 3o1200

Ethyl 3-oxobutanoate is treated with 1 equiv of $CH X_{3} MgBr$ in dry ether at $0\,^\circ\mathrm{C}$ , followed by a quick $H X_{3} O X^{+}$ work-up. The result is

A2,4-dimethylpentane-2,4-diol
Bethyl 3-methylbut-2-enoate
Cthe starting ester is recovered and methane is evolved
Dethyl 3-hydroxy-3-methylbutanoate

Answer: C

The

CH X_{2}

between the two carbonyls is far more acidic (pKa about 11) than any carbon acid reactive towards addition, so the Grignard, a strong base, deprotonates it (

CH X_{4}

evolves) giving a stabilised enolate. The enolate is not electrophilic, so no addition occurs, and work-up regenerates the starting ester.

Practice Organic Reaction Mechanisms I: Nucleophiles and Carbonyl Addition More on Nucleophilic acyl substitution of carboxylic acid derivatives

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Ethyl 3-oxobutanoate is treated with 1 equiv of CHX3​MgBr in dry ether at 0\,^\circ\mathrm{C}, followed by a quick HX3​OX+ work-up. The result is

Answer: C

More questions on Nucleophilic acyl substitution of carboxylic acid derivatives

Ethyl 3-oxobutanoate is treated with 1 equiv of $CH X_{3} MgBr$ in dry ether at $0\,^\circ\mathrm{C}$ , followed by a quick $H X_{3} O X^{+}$ work-up. The result is