Ethyl acetoacetate reacts with acetaldehyde ( CH ₃ CHO ) in the presence of a base and heat. The resulting intermediate is then subjected to acidic hydrolysis followed by heating. The major product formed is:

Step-by-step solution

The reaction between ethyl acetoacetate and acetaldehyde in the presence of a base proceeds via a Knoevenagel condensation followed by a Michael addition of a second molecule of ethyl acetoacetate. This forms a bis-adduct: CH₃CHO + 2 CH₃COCH₂COOC₂H₅ Base CH₃CH(CH(COCH₃)COOC₂H₅)₂ Under the basic conditions and heat, this intermediate undergoes an intramolecular aldol condensation. The enolate formed at one of the acetyl methyl groups attacks the carbonyl carbon of the other acetyl group, forming a six-membered ring.