UPSC Civil Services (Mains), Chemistry optional · 2023 · Paper II
Q4(a)(iii). Hydroboration–oxidation of a tetrasubstituted alkene
Question
Complete the above reactions and give suitable mechanism. [alkene treated with BH₃·THF to give (A), then H₂O₂, ⁻OH to give (B); structure given in the paper]
Model answer
The free solution for 2023 answers questions 1, 2, 3, 5 and 8, the ones picked in its time plan. Question 4 is answered in full in the Chemistry Paper II, 2021 to 2025 book, with every part of every paper.
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UPSC Civil Services (Main) Chemistry Paper II: Model Answers 2021 to 2025
- All eight questions of each paper, with the question printed above its answer
- Mechanisms drawn out and labelled on the scheme
- Topic-wise weightage and a topic-wise index
Covershydroboration–oxidationBH₃·THFanti-Markovnikov additionsyn additionorganoborane
All parts of Question 4
- 4(a)(i) Norbornene with D–Br5 marks
- 4(a)(ii) Relative rates of bromination in methanol5 marks
- 4(a)(iii) Hydroboration–oxidation of a tetrasubstituted alkene10 marks
- 4(b) Cyclic benzylammonium salt with NaNH₂ / NH₃10 marks
- 4(c)(i) Crossed aldol: butanone and acetaldehyde10 marks
- 4(c)(ii) Benzonitrile from benzene10 marks