Q9 · CSIR-NET Chemistry, June 2014
Paper: CSIR-NET June 2014 · Subject: Organic Chemistry · Chapter: Reagents, Reaction Mechanisms & Named Reactions · Topic: Reagents, Reaction Mechanisms & Named Reactions – General · Marks: 2 · Difficulty: Easy
Under review — part of this question (a structure or an option) is not clear in the source scan. 4AB is checking it against the original book; the answer shown may change.
The major products A and B in the following reaction sequence are: 
A 
B
A B(a)
B = 
B = (b)
B = 
B = (c)
(d)A = 
Answer
Under review — not yet confirmed.
Answer: A
Explanation
PhNCO/Et₃N dehydrates nitroethane to acetonitrile oxide, which adds stereospecifically to trans-2-butene to give the trans-4,5-dimethylisoxazoline A; Raney Ni/H₂ cleaves N–O and hydrolyses the imine to the β-hydroxyketone (a).
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