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

26. Amines

Nitrogenous Nucleophiles

Organic Chemistry

26. Amines

Nitrogenous Nucleophiles

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2:20 minutes

Problem 28

Textbook Question

Provide a mechanism for the protection of the amine as the benzylcarbamate shown in Figure 26.33(a). <IMAGE>

Verified step by step guidance

Identify the amine group in the molecule that needs to be protected. The amine group typically contains a nitrogen atom bonded to hydrogen atoms or alkyl groups.

Select the protecting group for the amine. In this case, the benzylcarbamate group is used, which is derived from benzyl chloroformate.

React the amine with benzyl chloroformate. This reaction typically occurs in the presence of a base, such as triethylamine, to neutralize the hydrochloric acid byproduct and facilitate the formation of the carbamate linkage.

The mechanism involves the nucleophilic attack of the nitrogen atom of the amine on the carbonyl carbon of the benzyl chloroformate, forming a tetrahedral intermediate.

The intermediate collapses, expelling the chloride ion and forming the benzylcarbamate-protected amine. This step completes the protection of the amine group.

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Key Concepts

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

Amine Protection

Amine protection is a strategy used in organic synthesis to temporarily mask the reactivity of an amine group. This is crucial when multiple functional groups are present, and selective reactions are needed. Protecting groups, like benzylcarbamate, are introduced to prevent unwanted reactions at the amine site, allowing for selective transformations elsewhere in the molecule.

Benzylcarbamate Formation

Benzylcarbamate is a common protecting group for amines, formed by reacting an amine with benzyl chloroformate. This reaction typically involves nucleophilic attack by the amine on the carbonyl carbon of benzyl chloroformate, followed by the release of hydrochloric acid. The resulting benzylcarbamate is stable under a variety of conditions, making it a versatile choice for protection.

Reaction Mechanism

Understanding the reaction mechanism involves detailing the step-by-step process by which reactants are converted to products. For amine protection with benzylcarbamate, the mechanism includes nucleophilic attack, formation of a tetrahedral intermediate, and subsequent elimination of a leaving group. This mechanistic insight is essential for predicting reaction outcomes and troubleshooting synthetic challenges.

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