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

13. Alcohols and Carbonyl Compounds

Nucleophilic Addition

Organic Chemistry

13. Alcohols and Carbonyl Compounds

Nucleophilic Addition

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Problem 46

Textbook Question

Why is a ketone more reactive/electrophilic than an ester?

Verified step by step guidance

Understand the concept of electrophilicity: Electrophilicity refers to the ability of a molecule to accept electrons. A molecule is more electrophilic if the carbon atom in the carbonyl group (C=O) is more electron-deficient, making it more susceptible to nucleophilic attack.

Analyze the electronic effects in a ketone: In a ketone, the carbonyl carbon is bonded to two alkyl groups. Alkyl groups are electron-donating through inductive effects, but they do not significantly stabilize the partial positive charge on the carbonyl carbon. This makes the carbonyl carbon in a ketone moderately electrophilic.

Analyze the electronic effects in an ester: In an ester, the carbonyl carbon is bonded to an alkoxy group (-OR) in addition to an alkyl group. The alkoxy group has a lone pair of electrons on the oxygen atom, which can delocalize into the carbonyl group through resonance. This resonance effect reduces the partial positive charge on the carbonyl carbon, making it less electrophilic compared to a ketone.

Compare resonance stabilization: The resonance stabilization in an ester (due to the lone pair on the oxygen atom) is stronger than the inductive effects of the alkyl groups in a ketone. This additional stabilization in the ester decreases the reactivity of the carbonyl carbon toward nucleophiles.

Conclude the comparison: Since the carbonyl carbon in a ketone is less stabilized (and thus more electron-deficient) compared to that in an ester, a ketone is more reactive and electrophilic than an ester.

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Key Concepts

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

Electrophilicity

Electrophilicity refers to the tendency of a molecule to accept electrons, making it a key player in chemical reactions. In organic chemistry, electrophiles are often positively charged or have a partial positive charge due to electronegative atoms. The greater the electrophilicity, the more reactive the compound is towards nucleophiles, which donate electrons.

Functional Groups: Ketones vs. Esters

Ketones and esters are both carbonyl-containing functional groups, but they differ in structure and reactivity. Ketones have a carbonyl group (C=O) bonded to two carbon atoms, while esters have a carbonyl group bonded to an oxygen atom, which is further connected to another carbon chain. This structural difference influences their reactivity, with ketones generally being more electrophilic due to less steric hindrance and stronger resonance stabilization in esters.

Resonance Stabilization

Resonance stabilization occurs when a molecule can be represented by multiple valid Lewis structures, distributing electron density across the molecule. In esters, the lone pair on the oxygen can delocalize into the carbonyl, reducing the electrophilicity of the carbonyl carbon. In contrast, ketones lack this resonance effect, making their carbonyl carbon more susceptible to nucleophilic attack, thus increasing their reactivity.

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