Problem: The Claisen condensation converts 2 molecules of an ester into a β-keto ester. The reaction starts with the ester in an alkoxide/alcohol solution and is worked up with acid to form the neutral β-keto ester product.Show the curved-arrow mechanism for the Claisen condensation of ethyl ethanoate treated with ethoxide ion. Include all formal charges and nonbonding electrons. In each step, draw only the species that react in that step. If an enolate resonance form is possible, draw only the carbanionic form. If a CHx group is being deprotonated, draw all H's on the reacting site. Tip: always omit ethanol byproducts. Step 1. Add curved arrows.Step 2. Draw the ester-containing intermediate produced from step 1 and draw the next reactant or reagent, if applicable. Add curved arrows. Step 3. Draw the ester-containing intermediate produced from step 2 and draw the next reactant or reagent, if applicable. Add curved arrows. Step 4. Draw the ester-containing intermediate produced from step 3 and draw the next reactant or reagent, if applicable. Add curved arrows. Step 5. Draw the ester-containing intermediate produced from step 4 and draw the final reagent, H3O+. Add curved arrows. 

🤓 Based on our data, we think this question is relevant for Professor Wickenden's class at UBC.

FREE Expert Solution

For this Claisen condensation, the mechanism will follow:

(1) Deprotonation (formation of enolate)

(2) Nucleophilic addition

(3) Elimination

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Problem Details

The Claisen condensation converts 2 molecules of an ester into a β-keto ester. The reaction starts with the ester in an alkoxide/alcohol solution and is worked up with acid to form the neutral β-keto ester product.

Show the curved-arrow mechanism for the Claisen condensation of ethyl ethanoate treated with ethoxide ion. Include all formal charges and nonbonding electrons. In each step, draw only the species that react in that step. If an enolate resonance form is possible, draw only the carbanionic form. If a CHx group is being deprotonated, draw all H's on the reacting site. Tip: always omit ethanol byproducts. 

Step 1. Add curved arrows.

Step 2. Draw the ester-containing intermediate produced from step 1 and draw the next reactant or reagent, if applicable. Add curved arrows. 

Step 3. Draw the ester-containing intermediate produced from step 2 and draw the next reactant or reagent, if applicable. Add curved arrows. 

Step 4. Draw the ester-containing intermediate produced from step 3 and draw the next reactant or reagent, if applicable. Add curved arrows. 

Step 5. Draw the ester-containing intermediate produced from step 4 and draw the final reagent, H3O+. Add curved arrows. 

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What scientific concept do you need to know in order to solve this problem?

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Based on our data, we think this problem is relevant for Professor Wickenden's class at UBC.