JEE Main levelSingle correct optionDifficulty 2 of 3o1070
Cyclohexanone is heated with piperidine and a trace of p-toluenesulphonic acid, with removal of water. The main organic product is
Acyclohexanone piperidine oxime
BN-cyclohexylidenepiperidinium chloride isolated as a neutral imine
C1-(cyclohex-1-en-1-yl)piperidine
D1-cyclohexylpiperidine
Answer: C
A secondary amine adds to the ketone to give a carbinolamine, but the resulting iminium ion has no N-H to lose and so loses an alpha proton instead, giving the enamine. The product is 1-(cyclohex-1-en-1-yl)piperidine.