UPSC Civil Services (Mains), Chemistry optional · 2024 · Paper II
Q7(b). X, Y and Z from an N-Boc piperidine aldehyde
Question
Predict the structures of X, Y and Z in the following sequence of reactions: [N-Boc piperidine aldehyde] —LiAlH₄, THF, 0 °C→ X —1) BH₃/THF, 2) HO⁻, H₂O₂, H₂O→ Y —CrO₃, H₂SO₄→ Z. [starting structure given in the paper]
Model answer
The free solution for 2024 answers questions 1, 3, 5, 6 and 8, the ones picked in its time plan. Question 7 is answered in full in the Chemistry Paper II, 2021 to 2025 book, with every part of every paper.
Part of VKC Basic
Read the key points and the full model answer with VKC Basic
VKC Basic (₹999 for 6 months) opens every solved answer, the notes, the handbook and the daily answer archive. Every Mains test series includes it.
Printed copy and Kindle
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
CoversLiAlH₄ reductionhydroboration–oxidationJones oxidationN-Boc protecting groupchemoselectivity
All parts of Question 7
- 7(a) λmax of three dienones by Woodward–Fieser rules15 marks
- 7(b) X, Y and Z from an N-Boc piperidine aldehyde15 marks
- 7(c)(i) Two isomeric esters C₁₀H₁₂O₂10 marks
- 7(c)(ii) Fragment ions m/z 58 and m/z 9210 marks