Question

Self-condensation of two moles of ethyl acetate in presence of Sodium ethoxide yields:

• A. ethyl propionate
• B. ethyl butyrate
• C. acetoacetic ester
• D. methyl acetoacetate

Answer 1

The correct option is C

acetoacetic ester

To write the self-condensation product, we start with the ester and get to its enolate form (this is promoted by a strong base):


Once we get to the enolate, the carban ion nucleophile (another resonance form of the enolate) attacks the electrophilic carbonyl carbon in an acyl substitution that expels the ethoxide ion fo forge a new carbon - carbon bond. The major product is ethyl acetoacetate - also known as acetoacetic ester. This is the Claisen condensation.