Which of the following reactions leads to the formation of a product containing a carbon-carbon double bond (assuming the carbonyl compounds possess at least one -hydrogen)?

Step-by-step solution

The reaction of a primary amine with an aldehyde or ketone yields an imine, which contains a carbon-nitrogen double bond ( C=N ). The reaction of a secondary amine with an aldehyde or ketone possessing at least one -hydrogen yields an enamine. The mechanism involves the initial formation of a carbinolamine, which undergoes dehydration. Since there is no proton on the nitrogen atom to be lost, a proton is removed from the -carbon, resulting in the formation of a carbon-carbon double bond ( C=C ). Therefore, both 2^