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

10. Addition Reactions

Halohydrin

Organic Chemistry

10. Addition Reactions

Halohydrin

Previous problemNext problem

Problem 47

Textbook Question

When alkenes react with bromine in water, a halohydrin is produced. When water is replaced with methanol in this reaction, a different product is produced. Suggest a mechanism for the formation of this product.

Verified step by step guidance

Step 1: Begin by understanding the reaction conditions. The reaction involves an alkene reacting with bromine (Br₂) in the presence of methanol (CH₃OH) instead of water. Methanol acts as a nucleophile in this case.

Step 2: The first step in the mechanism is the electrophilic addition of bromine to the alkene. The π-electrons of the alkene attack the bromine molecule, leading to the formation of a bromonium ion intermediate. This intermediate is a three-membered ring structure where one bromine atom is positively charged.

Step 3: Methanol, being a nucleophile, attacks the bromonium ion. The attack occurs at the more substituted carbon of the bromonium ion due to steric and electronic factors, leading to the opening of the ring. This step results in the formation of a product where methanol is attached to one carbon and bromine to the other.

Step 4: After the nucleophilic attack, the proton on the methanol group is removed by a base (often the bromide ion, Br⁻, generated in the reaction). This deprotonation step stabilizes the product and completes the reaction.

Step 5: The final product is an ether derivative, specifically a bromomethoxy compound, where the alkene has been converted into a molecule with a bromine atom and a methoxy group (-OCH₃) attached to adjacent carbons.

Verified video answer for a similar problem:

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

Play a video:

Was this helpful?

Key Concepts

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

Electrophilic Addition

Electrophilic addition is a fundamental reaction mechanism for alkenes, where an electrophile reacts with the double bond of the alkene. In the case of bromine reacting with alkenes, the bromine molecule becomes polarized, allowing the bromine cation to add to one carbon of the double bond while the other carbon forms a bond with a nucleophile, such as water or methanol, leading to the formation of a halohydrin or an ether.

Nucleophilic Substitution

Nucleophilic substitution is a reaction where a nucleophile replaces a leaving group in a molecule. In the context of the reaction with methanol, the methanol acts as a nucleophile, attacking the positively charged carbon that results from the electrophilic addition of bromine. This substitution leads to the formation of an ether instead of a halohydrin, showcasing how the solvent can influence the product of the reaction.

Regioselectivity

Regioselectivity refers to the preference of a chemical reaction to yield one structural isomer over others when multiple possibilities exist. In the reaction of alkenes with bromine in different solvents, the regioselectivity is influenced by the nature of the nucleophile (water vs. methanol) and the stability of the carbocation intermediate formed during the reaction. Understanding regioselectivity is crucial for predicting the major product in these reactions.

Watch next

Master General properties of halohydrin formation. with a bite sized video explanation from Johnny

Start learning

Related Videos

Related Practice

Textbook Question

Predict the product(s) that would result when the alkenes are allowed to react under the following conditions: (iv) Cl₂, CH₃OH

(h)

Textbook Question

Predict the product(s) that would result when the alkenes are allowed to react under the following conditions: (iii) Br₂, H₂O

(k)

Textbook Question

Predict the product(s) that would result when the alkenes are allowed to react under the following conditions: (iv) Cl₂, CH₃OH

(k)

Textbook Question

At the beginning of Chapter 9, we stated that after finishing Chapters 8 and 9, we would have the ability to make a large variety of functional groups using related reactions. Show the reagent(s) necessary to convert 1-isobutylcyclohexene into the following molecules.

(c)

Textbook Question

Explain why water attacks the carbon of the bromonium ion as opposed to the bromonium ion itself in the second step of halohydrin formation.

Textbook Question

Suggest an alkene that could be used to make each of the following halohydrins.

(c)

Textbook Question

Predict the product(s) that would result when the alkenes are allowed to react under the following conditions: (iii) Br₂, H₂O ; (iv) Cl₂, CH₃OH.

(e)

Textbook Question

Predict the product of the following haloalkane syntheses.

(e)