Q20 · CSIR NET Chemistry, June 2013
Paper: CSIR NET June 2013 · Subject: Organic Chemistry · Chapter: Reagents, Reaction Mechanisms & Named Reactions · Topic: Named Reactions · Marks: 2 · Difficulty: Medium
The major product formed in the following reaction is: 
1. NaH, $\mathrm{CS_2}$, MeI 
1. NaH, $\mathrm{CS_2}$, MeI (a)
(b)
(c)
(d)
Answer
Answer: A ✓ checked by 4AB · confidence high
Explanation
Chugaev syn-elimination of the xanthate needs a cis β-hydrogen. The methyl is cis to the O, so its carbon offers no syn H and elimination occurs toward the CH₂, giving the cyclohexene with the methyl on an sp³ carbon (a).
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