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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6:17 minutes

Problem 63e

Textbook Question

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

Verified step by step guidance

Step 1: Identify the reaction type. This is a Claisen condensation, which involves the reaction of an ester with a base to form a β-keto ester or a β-diketone.

Step 2: Analyze the structure of the reactant. The molecule contains two ester groups: one with a methoxy group (-OCH3) and another with a methyl group (-CH3). The base used is sodium methoxide (NaOCH3), which will deprotonate the α-hydrogen (hydrogen adjacent to the carbonyl group) of the ester.

Step 3: Deprotonation occurs at the α-carbon of the ester group with the methoxy substituent. This generates an enolate ion, which is nucleophilic and can attack the carbonyl carbon of the other ester group.

Step 4: The enolate ion attacks the carbonyl carbon of the second ester group, leading to the formation of a new C-C bond. This results in the formation of a tetrahedral intermediate, which subsequently collapses to expel the methoxy group (-OCH3) as a leaving group.

Step 5: The final product is a β-diketone structure, where the two carbonyl groups are separated by a single carbon atom. This is the typical product of a Claisen condensation 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 base deprotonates the alpha hydrogen of the ester, generating a nucleophile that attacks the carbonyl carbon of another ester, leading to the formation of a new carbon-carbon bond.

Enolate Ion

An enolate ion is a resonance-stabilized anion formed when a hydrogen atom is removed from the alpha carbon of a carbonyl compound, such as an ester or ketone. This ion acts as a nucleophile in various organic reactions, including Claisen condensation. The stability of the enolate ion is crucial for the reaction's success, as it determines the reactivity and the products formed during the condensation.

Reaction Conditions

The reaction conditions for Claisen condensation typically involve the use of a strong base, such as sodium ethoxide or sodium hydride, and a solvent like ethanol or methanol. These conditions facilitate the deprotonation of the ester and the subsequent nucleophilic attack on the carbonyl carbon. The choice of base and solvent can influence the reaction's efficiency and the stability of the intermediates formed during the process.

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

Key Concepts

Claisen Condensation

Enolate Ion

Reaction Conditions

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