Q53E

Question

Treatment of the minor product formed in the intramolecular aldol cyclization of 2,5-heptanedione (Problems 23-51 and 23-52) with aqueous NaOH converts it into the major product. Propose a mechanism to account for this base-catalyzed isomerization.

Step-by-Step Solution

Verified
Answer

The mechanism for the minor product formed in the intramolecular aldol cyclization of 2,5-heptanedione is reversible aldol condensation.

1Mechanism

In this reaction mechanism all steps are reversible aldol condensation hence stable compounds are formed at equilibrium.

The reaction starts with the addition of the -OH group and ends with aldol condensation and dehydration.

2The mechanism to convert the minor product into major: