Indian Forest Service (Mains), Chemistry optional · 2021 · Paper II
Q3(b)(ii). Intramolecular aldol condensation
Question
Predict the product of CH₃CO(CH₂)₄CHO with KOH in methanol on heating and give the mechanism.
Answer in brief
The favourable cyclization gives 1-acetylcyclopent-1-ene after aldol addition and dehydration.
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Coversintramolecular aldol condensation1-acetylcyclopentenefive-membered ring formationE1cb dehydrationenolate
All parts of Question 3
- 3(a)(i) Hydrogen exchange in cyclopropyl ketones5 marks
- 3(a)(ii) Strongly shielded internal methyl groups5 marks
- 3(b)(i) Carbon–carbon bond formation from a bromoester5 marks
- 3(b)(ii) Intramolecular aldol condensation5 marks
- 3(c)(i) ESR resonance field5 marks
- 3(c)(ii) Aromaticity of five-membered heterocycles5 marks
- 3(d)(i) Haworth synthesis of a methoxytetralone5 marks
- 3(d)(ii) Cyanide substitution on a nitroaryl halide5 marks