Q27 · CSIR-NET Chemistry, December 2013
Paper: CSIR-NET December 2013 · Subject: Organic Chemistry · Chapter: Reagents, Reaction Mechanisms & Named Reactions · Topic: Reagents, Reaction Mechanisms & Named Reactions – General · Marks: 2 · Difficulty: Medium
The major product formed in the following reaction sequence is: 1. $\mathrm{BH}_{3}, \mathrm{THF} ; \mathrm{H}_{2} \mathrm{O}_{2} / \mathrm{NaOH}$ 2. $\mathrm{Ph}_{3} \mathrm{P}, \mathrm{DEAD}, 4$-nitrobenzoic acid 3. $\mathrm{K}_{2} \mathrm{CO}_{3}, \mathrm{MeOH}$ 
(a)
(b)
(c)
(d)
Answer
Answer: A ✓ checked by 4AB · confidence medium
Explanation
Hydroboration of α-pinene from the face opposite the gem-dimethyl bridge gives isopinocampheol (OH trans to the C-2 methyl); Mitsunobu with p-nitrobenzoic acid inverts C-3 and K₂CO₃/MeOH cleaves the ester, giving neoisopinocampheol with OH cis to the methyl (a).
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