Q74 · CSIR NET Chemistry, December 2012
Paper: CSIR NET December 2012 · Subject: Organic Chemistry · Chapter: Pericyclic Reactions · Topic: Sigmatropic Shifts · Marks: 2 · Difficulty: Medium
The following transformation involves 
+ 
$\mathrm{H^{+}}$ 
+ $\mathrm{H^{+}}$ (a)an iminium ion, [3, 3]-sigmatropic shift and Mannich reaction.
(b)a nitrenium ion, [3, 3]-sigmatropic shift and Michael reaction.
(c)an iminium ion, [1, 3]-sigmatropic shift and Mannich reaction.
(d)a nitrenium ion, [1,3]-sigmatropic shift and Michael reaction.
Answer
Answer: A ✓ checked by 4AB · confidence high
Explanation
The aldehyde and methylamine form an iminium ion; a cationic 2-aza-Cope ([3,3]) rearrangement then places the enol and the new iminium for an intramolecular Mannich cyclisation (aza-Cope/Mannich).
Study loop for Pericyclic Reactions