Indian Forest Service (Mains), Chemistry optional · 2024 · Paper II
Q4(b). Stobbe condensation
Question
Give the product and mechanism of cyclohexanone with diethyl succinate in strong base followed by aqueous acid.
Answer in brief
The Stobbe product is the alkylidenesuccinic half-ester EtOOC–C(=C₆H₁₀)–CH₂–COOH, with the exocyclic double bond attached to a cyclohexane ring.
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CoversStobbe condensationdiethyl succinatehalf-esterγ-lactone intermediatealkylidenesuccinic acid
All parts of Question 4
- 4(a) Grignard addition and competing reduction10 marks
- 4(b) Stobbe condensation10 marks
- 4(c)(i) Benzoin exchange in cyanide10 marks
- 4(c)(ii) Bischler–Napieralski cyclization10 marks