JEE Main 2022 · 27 Jul · Shift 2 · Chemistry Q72 · Dronacharya Exams

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ChemistrySingle correct+4 / -1Question 72 of 90

The structure of A in the given reaction is :

A methyl ketone R-CO-CH3 treated with NaOH and ethyl bromide (CH3CH2Br) gives A, the major product.

A

R-C(OH)(CH₃)-CH(CH₃)Br

R-C(OH)(CH3)-CH(CH3)Br.

B

R-C(OH)(CH₃)-CH₂CH₃

R-C(OH)(CH3)-CH2CH3.

C

R-CO-CH₂CH₂CH₃

R-CO-CH2CH2CH3 (α-ethylated ketone).

D

R-CO-CH₂CH₂CH₂OH

Ketone R-CO-CH2CH2CH2OH with a terminal hydroxyl.

Answer and worked solution

Official answer: C

Enolate alkylation. NaOH forms the enolate at the methyl group, which is alkylated by ethyl bromide: $\mathrm{R{-}CO{-}CH_2CH_2CH_3}$ .

(C)

Topics:Aldol and related condensations SN1 and SN2

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