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

Crossed Aldol Condensation

Organic Chemistry

25. Condensation Chemistry

Crossed Aldol Condensation

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5:23 minutes

Problem 62e

Textbook Question

Predict the products of the following aldol condensations. Show the products both before and after dehydration.
(e)

Verified step by step guidance

Step 1: Identify the reactants involved in the aldol condensation. The first reactant is cyclohexane-1,3-dione, which has two alpha hydrogens available for enolate formation. The second reactant is furfural, an aldehyde with an aromatic furan ring.

Step 2: Determine the enolate formation. Under basic conditions (-OH), cyclohexane-1,3-dione will form an enolate ion at one of its alpha positions. This enolate will act as a nucleophile.

Step 3: Perform the nucleophilic attack. The enolate ion from cyclohexane-1,3-dione will attack the carbonyl carbon of furfural, forming a β-hydroxy ketone intermediate. This is the product before dehydration.

Step 4: Dehydration step. Under the reaction conditions, the β-hydroxy ketone intermediate will undergo dehydration (loss of water) to form an α,β-unsaturated ketone. This involves the elimination of a hydroxyl group and a hydrogen atom, creating a double bond between the alpha and beta carbons.

Step 5: Draw the final product. The final product after dehydration will be a conjugated system with a double bond between the alpha and beta carbons of the cyclohexane ring, and the furfural group attached to the beta carbon.

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Key Concepts

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

Aldol Condensation

Aldol condensation is a reaction between aldehydes or ketones that contain alpha-hydrogens, leading to the formation of β-hydroxy aldehydes or ketones (aldols). This reaction involves the nucleophilic addition of an enolate ion to a carbonyl compound, followed by dehydration to yield an α,β-unsaturated carbonyl compound. Understanding this process is crucial for predicting the products of the reaction.

Dehydration in Aldol Reactions

Dehydration in aldol reactions refers to the elimination of a water molecule from the β-hydroxy carbonyl compound formed during the aldol condensation. This step is essential as it converts the aldol into a more stable α,β-unsaturated carbonyl compound, which is often the final product of the reaction. Recognizing the conditions that favor dehydration helps in predicting the final products.

Enolate Ion Formation

Enolate ions are key intermediates in aldol reactions, formed by the deprotonation of the alpha-hydrogen of a carbonyl compound. This ion acts as a nucleophile, attacking another carbonyl carbon to initiate the aldol condensation. Understanding how enolate ions are generated and their reactivity is vital for predicting the outcome of the aldol condensation process.

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