UPSC Combined Geo-Scientist, Mains · 2020 · Mains Paper III
Q6(f). Diene reactivity in Diels–Alder reactions
Question
Order the depicted dienes: I 2,3-dimethylbutadiene, II 1-methylenecyclopent-2-ene, III (Z,Z)-hexa-2,4-diene and IV cyclopentadiene.
Answer in brief
The usual order is IV > I > III > II.
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CoversDiene reactivity in Diels–Alder reactionsConformational control
All parts of Question 6
- 6(a) Dichlorocarbene ring expansion4 marks
- 6(b) Anionic polymerisation of substituted styrenes4 marks
- 6(c) Cyanohydrin formation and hydrolysis4 marks
- 6(d) Doebner condensation4 marks
- 6(e) Hydration with skeletal rearrangement4 marks
- 6(f) Diene reactivity in Diels–Alder reactions4 marks
- 6(g) Norrish II reactivity4 marks
- 6(h) UV maximum of a dienone4 marks
- 6(i) Carbonyl stretching frequencies4 marks
- 6(j) Distinguishing three carbonyl compounds by proton NMR4 marks