Question

Claisen Condensations Claisen condensations involve the enolate anion of an ester which acts as a nucleophile attacking another molecule of ester. The resulting product of this reaction is a Beta-ketoester. Draw the enolate anion which serves as the nucleophile in the reaction above. Draw the resonance structure of this enolate. Look at the mechanism of this reaction in your textbook (7^th edition), pages 773-774. What type of reaction does this resemble, S_N1,S_N2, E1, or E2? Ethanol is one of the products in the reaction shown above. How did it form? Consider the two p-ketoesters shown below. Indicate the new C-C bond in each compound. Provide the esters that each compound was formed from.

Answer 1

Solution :-

Followingn image shows the mechanism steps and the formation of the enol and resonance of the enol. Also shows the mechanism steps for the fomation of the ethanol

the Base first takes the acidic proton from the estyer and produces the enolate ion then enolate ion reacts with another ester molecule and replace the alcoxy part of the ester and forms beta keto ester product.

The new C-C bonds for the given structures are also marked in the image