Q. Which of the following will react with cyclo pentanone to form an enamine?
Amines
Solution:
It is an example of Stork Enamine reaction $2^{\circ}$ amine, react with carbonyl compounds with at least one $\alpha$-H-atom and form enamine. (c) and (d) both are $2^{\circ}$ amine but in (c), lone pair $\bar{e}$ 's on $N$-atom are delocalised by resonance (LP $\bar{e}$ 's are in conjugation with (C=O) group). Hence in (3), basic character decreases as compound to (4).
