Q23 · CSIR-NET Chemistry, December 2019

Paper: CSIR-NET December 2019 · Subject: Organic Chemistry · Chapter: Reagents, Reaction Mechanisms & Named Reactions · Topic: Carbonyl Chemistry · Marks: 2 · Difficulty: Hard

E1cb mechanism is followed in the reaction of:
(a)2-bromopentane with t-BuOK to give pent-2-ene.
(b)Nitromethane with benzaldehyde in the presence of KOH to give $\beta$-styrene.
(c)Bromobenzene with NaNH₂ to give aniline.
(d)P-chloronitrobenzene with NaOMe to give p-nitroanisole.
Answer
Answer: B ✓ checked by 4AB · confidence high
Explanation
Dehydration of the nitroaldol (Henry) product goes through the stabilised nitronate carbanion — E1cB (b).

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