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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2:14 minutes

Problem 40c,d

Textbook Question

Some (but not all) of the following keto esters can be formed by Dieckmann condensations. Determine which ones are possible, and draw the starting diesters.
(c)
(d)

Verified step by step guidance

Step 1: Understand the Dieckmann condensation reaction. It is an intramolecular reaction where a diester undergoes base-catalyzed cyclization to form a β-keto ester. This reaction requires the diester to have two ester groups separated by a suitable number of carbons to form a stable ring.

Step 2: Analyze structure (A). The product shown is a bicyclic β-keto ester. To form this structure via Dieckmann condensation, the starting diester must have two ester groups positioned such that cyclization forms the bicyclic ring system. Verify if the ester groups are appropriately spaced for cyclization.

Step 3: Analyze structure (B). The product shown is a monocyclic β-keto ester. To form this structure via Dieckmann condensation, the starting diester must have two ester groups positioned such that cyclization forms the six-membered ring. Check if the ester groups are appropriately spaced for cyclization.

Step 4: Draw the starting diesters for both (A) and (B). For (A), the diester should have ester groups on carbons that allow formation of the bicyclic system. For (B), the diester should have ester groups on carbons that allow formation of the six-membered ring.

Step 5: Confirm the feasibility of the Dieckmann condensation for each structure. Ensure that the reaction conditions (base and solvent) would favor cyclization and that the resulting rings are stable (e.g., five- or six-membered rings are preferred).

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Key Concepts

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

Dieckmann Condensation

Dieckmann condensation is a type of intramolecular Claisen condensation that occurs between two ester groups in the presence of a strong base. This reaction typically leads to the formation of a β-keto ester or a cyclic compound. Understanding the conditions and mechanisms of this reaction is crucial for determining which keto esters can be synthesized from given diesters.

Keto Esters

Keto esters are organic compounds that contain both a ketone and an ester functional group. They are characterized by the presence of a carbonyl group (C=O) adjacent to an ester group (RCOOR'). The structure and reactivity of keto esters are important in organic synthesis, particularly in reactions like Dieckmann condensation, where they can serve as intermediates or products.

Starting Diesters

Starting diesters are the initial compounds used in the Dieckmann condensation process. They typically contain two ester functional groups that can react under basic conditions to form a cyclic product. Identifying the correct starting diesters is essential for predicting the possible keto esters that can be formed, as the structure and arrangement of these diesters influence the outcome of the reaction.

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