Question

Question: Draw the product formed when each dicarbonyl compound undergoes an intramolecular aldol reaction followed by dehydration.

Short answer

Answer

Step-by-step solution

Intra-molecular aldol reaction

This reaction produces a five or six-membered ring as the two carbonyl groups tend to make a C-C bond within the same compound.

Aldol product dehydration

Upon dehydration, the $\beta$-hydroxy carbonyl product of the aldol reaction forms an $\alpha ,\beta$-unsaturated aldehyde or ketone.

Product of the given reaction

a. Since the enolizable carbonyl group and the $\alpha$-carbon is 5 carbon atoms apart, the ring formed is five-membered.

Product of a.

b. Since the enolizable carbonyl group and the $\alpha$-carbon is 6 carbon atoms apart, the ring formed is six-membered.

Product of b.

c. Since the enolizable carbonyl group and the $\alpha$-carbon is 6 carbon atoms apart, the ring formed is six-membered.

Product of c.