In the following reaction (i) 2 eq. n-BuLi (ii) DMF [X] the major product [X] is: · ABC26OR0677
Subject: Organic Chemistry · Chapter: Reagents, Reaction Mechanisms & Named Reactions · Topic: Reagents, Reaction Mechanisms & Named Reactions – General · Exam: GATE 2000-2022 · Marks: 2 · Difficulty: Medium
In the following reaction 
(i) 2 eq. n-BuLi 
(ii) DMF $[\mathrm{X}]$ the major product $[\mathrm{X}]$ is:
(i) 2 eq. n-BuLi (ii) DMF $[\mathrm{X}]$ the major product $[\mathrm{X}]$ is:(a)
(b)
(c)
(d)
Answer
Answer: C ✓ checked by 4AB · confidence high
Explanation
Shapiro reaction: 2 equiv n-BuLi remove the N–H and then an α-H at the less substituted α-carbon (C-5, CH₂). Loss of Ts⁻ and N₂ gives the vinyllithium at C-1 with a C1=C5 double bond, and DMF formylates it. The product is 5-methylcyclopent-1-ene-1-carbaldehyde, with the methyl on the sp³ carbon next to the CHO-bearing alkene carbon. Answer (c).
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