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

Hofmann Elimination

Organic Chemistry

26. Amines

Hofmann Elimination

Previous problemNext problem

3:05 minutes

Problem 22a

Textbook Question

When the (R,R) isomer of the amine shown is treated with an excess of methyl iodide, then silver oxide, then heated, the major product is the Hofmann product.
(a) Draw the structure of the major (Hofmann) product.

Verified step by step guidance

Step 1: Recognize that the reaction involves the Hofmann elimination process, which occurs when an amine is treated with excess methyl iodide, followed by silver oxide and heat. This process converts the amine into a quaternary ammonium salt, which undergoes elimination to form an alkene.

Step 2: Analyze the starting amine structure. The given amine is a tertiary amine with two methyl groups and a bulky isopropyl group attached to the nitrogen. The elimination will occur to form the least substituted alkene (Hofmann product) due to steric hindrance.

Step 3: Treat the amine with excess methyl iodide. This step methylates the nitrogen, forming a quaternary ammonium iodide salt. The nitrogen now has a positive charge, and the iodide acts as a counterion.

Step 4: Add silver oxide (Ag2O) and water. This step replaces the iodide ion with a hydroxide ion, forming a quaternary ammonium hydroxide salt. The hydroxide ion acts as a base in the elimination reaction.

Step 5: Heat the quaternary ammonium hydroxide salt. The elimination reaction occurs, and the least substituted alkene (Hofmann product) is formed as the major product. In this case, the major product is the terminal alkene, as shown in the diagram.

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.

Hofmann Rearrangement

The Hofmann rearrangement is a chemical reaction that converts primary amides into primary amines with the loss of one carbon atom. This reaction involves the treatment of the amide with halogens and a base, leading to the formation of an isocyanate intermediate, which is then hydrolyzed to yield the amine. Understanding this mechanism is crucial for predicting the products when an amine is treated with methyl iodide and silver oxide.

Methylation of Amines

Methylation of amines involves the introduction of a methyl group into the amine structure, typically using methyl iodide as a methylating agent. This process can lead to the formation of N-methylated products, which can further react under certain conditions. Recognizing how methylation affects the structure and reactivity of amines is essential for determining the final product in the given reaction sequence.

Sterics and Reactivity in Organic Chemistry

Sterics refers to the spatial arrangement of atoms in a molecule and how this affects its reactivity. In the context of the (R,R) isomer of the amine, steric hindrance can influence the outcome of reactions, such as the Hofmann rearrangement and subsequent methylation. Understanding steric effects is vital for predicting which products will be favored in a reaction, especially when multiple pathways are possible.

Watch next

Master General Reaction with a bite sized video explanation from Johnny

Start learning