Q6(f). Cope rearrangement of a 1,5-diene
Predict the structure of the product and name the reaction. [1,5-diene given in the paper; Δ, THF, C₆H₆ → ?]
Answer in brief
Cope rearrangement. Product: 2-(but-3-en-1-yl)cyclohex-2-en-1-one, C₁₀H₁₄O, an isomer of the reactant.
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Topic notes: pericyclic reactions, with every Civil Services, IFoS and Geo-Scientist PYQ →
CoversCope rearrangement[3,3]-sigmatropic shift1,5-dienechair transition statepericyclic reaction
All parts of Question 6
- 6(a) Singlet and triplet carbenes; fluorenylidene with cis-but-2-ene4 marks
- 6(b) Bromine addition: styrene reacts faster than propene4 marks
- 6(c) Addition of HCl to an α,β-unsaturated acid4 marks
- 6(d) Michael addition of a cyclic 1,3-dione to cyclohex-2-enone4 marks
- 6(e) Hydroboration–oxidation of 1-methylcyclohexene4 marks
- 6(f) Cope rearrangement of a 1,5-diene4 marks
- 6(g) Diels–Alder reaction: product and reactants4 marks
- 6(h) IR distinction: hydrogen bonding and ring strain4 marks
- 6(i) McLafferty rearrangement: 2-pentanone and 3-pentanone4 marks
- 6(j) NMR assignment of 4-methylpent-1-yne4 marks