Table of contents

1. A Review of General Chemistry5h 5m
2. Molecular Representations1h 14m
3. Acids and Bases2h 46m
4. Alkanes and Cycloalkanes4h 17m
5. Chirality3h 39m
6. Thermodynamics and Kinetics1h 22m
7. Substitution Reactions1h 48m
8. Elimination Reactions2h 30m
9. Alkenes and Alkynes2h 9m
10. Addition Reactions3h 19m
11. Radical Reactions1h 58m
12. Alcohols, Ethers, Epoxides and Thiols2h 42m
13. Alcohols and Carbonyl Compounds2h 17m
14. Synthetic Techniques1h 26m
15. Analytical Techniques:IR, NMR, Mass Spect7h 3m
16. Conjugated Systems6h 13m
17. Ultraviolet Spectroscopy51m
18. Aromaticity2h 34m
19. Reactions of Aromatics: EAS and Beyond5h 1m
20. Phenols55m
21. Aldehydes and Ketones: Nucleophilic Addition4h 56m
22. Carboxylic Acid Derivatives: NAS2h 51m
23. The Chemistry of Thioesters, Phophate Ester and Phosphate Anhydrides1h 10m
24. Enolate Chemistry: Reactions at the Alpha-Carbon1h 53m
25. Condensation Chemistry2h 9m
26. Amines1h 43m
27. Heterocycles2h 0m
28. Carbohydrates5h 53m
29. Amino Acids4h 20m
30. Peptides and Proteins2h 42m
31. Catalysis in Organic Reactions1h 30m
32. Lipids 2h 50m
33. The Organic Chemistry of Metabolic Pathways2h 52m
34. Nucleic Acids1h 32m
35. Transition Metals6h 14m
36. Synthetic Polymers1h 49m

25. Condensation Chemistry

Claisen Condensation

Organic Chemistry

25. Condensation Chemistry

Claisen Condensation

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6:05 minutes

Problem 63d

Textbook Question

Predict the products of the following Claisen condensations.
(d)

Verified step by step guidance

Step 1: Identify the reactants involved in the Claisen condensation. The reaction involves cyclohexanone (a ketone) and methyl acetoacetate (an ester) in the presence of sodium methoxide (NaOCH3) as the base and methanol (CH3OH) as the solvent.

Step 2: Understand the mechanism of Claisen condensation. The base (NaOCH3) deprotonates the alpha-hydrogen of the ester (methyl acetoacetate), forming an enolate ion. This enolate ion is nucleophilic and will attack the electrophilic carbonyl carbon of the ketone (cyclohexanone).

Step 3: Write the nucleophilic attack step. The enolate ion formed from methyl acetoacetate attacks the carbonyl carbon of cyclohexanone, leading to the formation of a tetrahedral intermediate. This intermediate will rearrange to form a new carbon-carbon bond.

Step 4: Eliminate the leaving group. The tetrahedral intermediate collapses, expelling the methoxide ion (CH3O⁻) as the leaving group. This results in the formation of a β-keto ester product.

Step 5: Analyze the final product. The product of the reaction is a β-keto ester, where the new carbon-carbon bond connects the alpha-carbon of methyl acetoacetate to the carbonyl carbon of cyclohexanone. The structure of the product can be deduced by combining the fragments formed during the reaction.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Claisen Condensation

Claisen condensation is a reaction between two esters or an ester and a carbonyl compound in the presence of a strong base, typically an alkoxide. This reaction results in the formation of a β-keto ester or a β-diketone. The mechanism involves the deprotonation of an alpha hydrogen, followed by nucleophilic attack on the carbonyl carbon of another ester, leading to the formation of a new carbon-carbon bond.

Enolate Ion Formation

In Claisen condensation, the formation of an enolate ion is a crucial step. An enolate ion is generated when a strong base abstracts an alpha hydrogen from an ester, creating a resonance-stabilized anion. This enolate ion acts as a nucleophile, attacking the carbonyl carbon of another ester, which is essential for the condensation process to occur.

Product Prediction

Predicting the products of a Claisen condensation involves understanding the structure of the reactants and the regioselectivity of the reaction. The final product typically features a β-keto ester or β-diketone, depending on the starting materials. Additionally, the reaction conditions, such as the choice of base and solvent, can influence the outcome, including the possibility of side reactions or further condensation.

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Predict the products of the following Claisen condensations. (d)

Key Concepts

Claisen Condensation

Enolate Ion Formation

Product Prediction

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Predict the products of the following Claisen condensations.
(d)