Q9(b). Dieckmann condensation, then hydrolysis and decarboxylation
In the following reactions, identify the products A and B. Explain the mechanism of formation of A: [structure of the aromatic diester given in the paper], CH₃ONa/CH₃OH → A; 48% HBr, Δ → B.
Answer in brief
A = methyl 1-oxo-1,2,3,4-tetrahydronaphthalene-2-carboxylate (cyclic β-keto ester). B = α-tetralone, 3,4-dihydronaphthalen-1(2H)-one.
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CoversDieckmann condensationintramolecular Claisenβ-keto esterdecarboxylationα-tetralone
All parts of Question 9
- 9(a) Structure from UV, IR, NMR and mass data: C₇H₈BrN10 marks
- 9(b) Dieckmann condensation, then hydrolysis and decarboxylation5 marks
- 9(c) Beer’s law for camphor; λmax of the methyl halides5 marks
- 9(d)(i) Birch reduction with ring closure: a spiro acid5 marks
- 9(d)(ii) Robinson annulation to a spiro enone5 marks