Q8(c). Cyclohexane-1,2-dione and NaOH: benzilic acid ring contraction
While proposing a suitable mechanism, write down the product(s) obtained in the following dicarbonyl compound on treatment with base: cyclohexane-1,2-dione, NaOH → ? [structure given in the paper]
Model answer
The free solution for 2021 answers questions 1, 2, 5, 6, 7 and 10, the ones picked in its time plan. Question 8 is answered in full in the Geo-Scientist Chemistry Paper III, 2021 to 2025 book, with every part of every paper.
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UPSC Combined Geo-Scientist (Main) Chemistry Paper III: Model Answers 2021 to 2025
- All ten questions of each paper, with the question printed above its answer
- Instruments drawn as labelled diagrams, numericals worked with units
- Topic-wise weightage and a topic-wise index
Topic notes: molecular rearrangements, with every Civil Services, IFoS and Geo-Scientist PYQ →
Coversbenzilic acid rearrangementring contraction1,2-diketonecyclohexane-1,2-dione
All parts of Question 8
- 8(a) Cyclohexanone: Wolff–Kishner reduction and Reformatsky reaction10 marks
- 8(b) Eucarvone and light: 4π electrocyclic ring closure8 marks
- 8(c) Cyclohexane-1,2-dione and NaOH: benzilic acid ring contraction4 marks
- 8(d) 2-Butenes: anti addition of bromine, syn hydroxylation8 marks