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

24. Enolate Chemistry: Reactions at the Alpha-Carbon

Enolate

Organic Chemistry

24. Enolate Chemistry: Reactions at the Alpha-Carbon

Enolate

Previous problemNext problem

2:02 minutes

Problem 3e

Textbook Question

Give the important resonance forms for the possible enolate ions of the following:
(e)

Verified step by step guidance

Step 1: Identify the alpha-hydrogens in the molecule. Alpha-hydrogens are hydrogens attached to the carbon atoms adjacent to the carbonyl group. In this molecule, there are alpha-hydrogens on both sides of the ketone group.

Step 2: Determine the possible enolate ions that can form. Deprotonation of the alpha-hydrogens by a base will result in the formation of enolate ions. The enolate ion can form on either side of the ketone group, leading to two possible enolate structures.

Step 3: Draw the resonance forms for the enolate ions. For each enolate ion, the negative charge on the alpha-carbon can delocalize onto the oxygen atom of the carbonyl group, forming resonance structures. Use curved arrows to show the movement of electrons.

Step 4: Analyze the stability of the resonance forms. Resonance structures where the negative charge is on the oxygen atom are generally more stable due to oxygen's higher electronegativity. This contributes to the overall stability of the enolate ion.

Step 5: Consider the conjugation with the double bonds in the cyclohexene ring. The enolate ion formed on the side closer to the cyclohexene ring may have additional resonance stabilization due to conjugation with the double bonds in the ring system.

Verified video answer for a similar problem:

This video solution was recommended by our tutors as helpful for the problem above

Video duration:

Play a video:

Was this helpful?

Key Concepts

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

Enolate Ions

Enolate ions are reactive intermediates formed from the deprotonation of an alpha-hydrogen adjacent to a carbonyl group. They play a crucial role in various organic reactions, particularly in nucleophilic addition and condensation reactions. The stability of enolate ions is influenced by resonance, which allows the negative charge to be delocalized between the alpha-carbon and the carbonyl oxygen.

Resonance Structures

Resonance structures are different Lewis structures for the same molecule that illustrate the delocalization of electrons. In the case of enolate ions, resonance forms show how the negative charge can be shared between the alpha-carbon and the carbonyl oxygen, enhancing the stability of the ion. Understanding these structures is essential for predicting reactivity and stability in organic reactions.

Alpha-Carbon Chemistry

The alpha-carbon is the first carbon atom attached to a functional group, such as a carbonyl. In enolate chemistry, the alpha-carbon is significant because it is where deprotonation occurs to form the enolate ion. The reactivity of the alpha-carbon is influenced by the presence of electron-withdrawing groups, which can stabilize the negative charge of the enolate through resonance.

Watch next

Master Formation of Enolates with a bite sized video explanation from Johnny

Start learning

Related Videos

Related Practice

Textbook Question

For each molecule shown below,

1. indicate the most acidic hydrogens.

2. draw the important resonance contributors of the anion that results from removal of the most acidic hydrogen.

(g)

Textbook Question

For each molecule shown below,

1. indicate the most acidic hydrogens.

2. draw the important resonance contributors of the anion that results from removal of the most acidic hydrogen.

(h)

Textbook Question

Give the important resonance forms for the possible enolate ions of the following:

Textbook Question

Give the important resonance forms for the possible enolate ions of the following:

(d)

Textbook Question

Give the important resonance forms for the possible enolate ions of the following:

(f)

Textbook Question

Show the resonance forms for the enolate ions that result when the following compounds are treated with a strong base.

(a) ethyl acetoacetate

(b) pentane-2,4-dione

Textbook Question

When cis-2,4-dimethylcyclohexanone is dissolved in aqueous ethanol containing a trace of NaOH, a mixture of cis and trans isomers results. Propose a mechanism for this isomerization.

Textbook Question

For each molecule shown below,

1. indicate the most acidic hydrogens.

2. draw the important resonance contributors of the anion that results from removal of the most acidic hydrogen.

(d)

Show more practices