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

22. Carboxylic Acid Derivatives: NAS

Nucleophilic Acyl Substitution

Organic Chemistry

22. Carboxylic Acid Derivatives: NAS

Nucleophilic Acyl Substitution

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8:45 minutes

Problem 30

Textbook Question

Which compound forms an anhydride more rapidly?

Verified step by step guidance

Step 1: Analyze the chemical structures of Ion A and Ion B. Ion A has two carboxylate groups adjacent to each other, while Ion B has a carboxylate group separated by a methylene (-CH2-) group from another carboxylate group.

Step 2: Recall that anhydride formation typically occurs when two carboxylic acid groups or their derivatives are close enough to interact and form a cyclic or linear anhydride. The proximity of the functional groups is crucial for the reaction to proceed rapidly.

Step 3: Consider steric and electronic factors. In Ion A, the carboxylate groups are directly adjacent, which facilitates intramolecular anhydride formation. In Ion B, the methylene group introduces a spatial separation, making the interaction between the carboxylate groups less favorable.

Step 4: Evaluate the resonance stabilization and reactivity. Ion A's structure allows for better alignment of the reactive groups, while Ion B's structure is less conducive to rapid anhydride formation due to the increased distance and reduced interaction.

Step 5: Conclude that Ion A forms an anhydride more rapidly due to the closer proximity of its carboxylate groups, which facilitates intramolecular reaction and minimizes steric hindrance.

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Key Concepts

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

Anhydride Formation

Anhydrides are formed through the condensation of two carboxylic acids or a carboxylic acid and an acid chloride, resulting in the loss of water. The rate of anhydride formation can be influenced by the stability of the intermediates and the leaving groups involved in the reaction. Understanding the mechanism of this reaction is crucial for predicting which compound will form an anhydride more rapidly.

Electrophilicity

Electrophilicity refers to the tendency of a compound to attract electrons, making it more reactive in nucleophilic reactions. In the context of anhydride formation, the presence of electron-withdrawing groups can enhance the electrophilicity of the carbonyl carbon, facilitating the reaction. Analyzing the structures of Ion A and Ion B helps determine which compound has a more electrophilic carbonyl, thus influencing the rate of anhydride formation.

Resonance Stabilization

Resonance stabilization occurs when a molecule can be represented by multiple valid Lewis structures, distributing electron density and lowering the overall energy of the molecule. In the case of Ion A and Ion B, the presence of resonance structures can affect the stability of the intermediates formed during anhydride formation. A more stable intermediate will lead to a faster reaction rate, making resonance an important factor in determining which compound forms an anhydride more rapidly.

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Related Practice

Textbook Question

Predict the product of the following reaction sequences.

(a)

Textbook Question

How can the following compounds be prepared from the given starting materials?

Textbook Question

Show how you would synthesize each compound, starting with an ester containing no more than eight carbon atoms. Any other necessary reagents may be used.

(a) Ph₃C–OH

(b) (PhCH₂)₂CHOH

Textbook Question

Show how to synthesize the following amines from the indicated starting materials by acylation–reduction.

(a) N-butylpiperidine from piperidine

(b) N-benzylaniline from aniline

Textbook Question

b. What is the product of the reaction of acetamide with HO⁻? The pK_a of NH₃ is 36; the pK_a of H₂O is 15.7.

Textbook Question

What is the product of an acyl substitution reaction—a new carboxylic acid derivative, a mixture of two carboxylic acid derivatives, or no reaction—if the new group in the tetrahedral intermediate is the following? a. a stronger base than the substituent that is attached to the acyl group

Textbook Question

What is the product of an acyl substitution reaction—a new carboxylic acid derivative, a mixture of two carboxylic acid derivatives, or no reaction—if the new group in the tetrahedral intermediate is the following? b. a weaker base than the substituent that is attached to the acyl group

Textbook Question

Using the pK_a values listed in [TABLE 15.1], predict the products of the following reactions:

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