Q7(b). Ketone with diethyl carbonate: crossed Claisen condensation
Identify the product in the following reaction and justify your answer: [a methyl ketone with diethyl carbonate; i) EtO⁻, EtOH; ii) CH₃COOH; structures given in the paper]
Answer in brief
Ethyl 4-methyl-3-oxopentanoate, (CH₃)₂CH–CO–CH₂–CO₂C₂H₅: the ketone is acylated on its CH₃ side by diethyl carbonate (crossed Claisen condensation).
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Coverscrossed Claisen condensationdiethyl carbonateβ-keto esterenolate acylation3-methylbutan-2-one
All parts of Question 7
- 7(a) Acetylene on a Ziegler–Natta catalyst: polyacetylene10 marks
- 7(b) Ketone with diethyl carbonate: crossed Claisen condensation5 marks
- 7(c) Lactic acid from ethanal through the cyanohydrin5 marks
- 7(d) Phenyl acetate to A, B, C, D: Reimer–Tiemann and Wittig reactions10 marks