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

11. Radical Reactions

Allylic Bromination

Organic Chemistry

11. Radical Reactions

Allylic Bromination

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2:30 minutes

Problem 31a

Textbook Question

What is the major product of the following reactions? Disregard stereoisomers:
a.

Verified step by step guidance

Step 1: Recognize the reagents and reaction conditions. NBS (N-Bromosuccinimide) in the presence of peroxide and heat is commonly used for allylic bromination. This reaction selectively replaces a hydrogen atom at the allylic position (a carbon adjacent to a double bond) with a bromine atom.

Step 2: Identify the allylic positions in the given molecule. The starting material is cyclopentene, which has two allylic positions: one on each carbon adjacent to the double bond.

Step 3: Determine the most reactive allylic position. Both allylic positions in cyclopentene are equivalent due to symmetry, so bromination can occur at either position.

Step 4: Predict the major product. Bromination at the allylic position will result in the formation of 3-bromocyclopentene. Since stereoisomers are disregarded, only the structure of the major product is considered.

Step 5: Understand the mechanism. The reaction proceeds via a radical mechanism initiated by the peroxide and heat. The peroxide generates bromine radicals, which abstract an allylic hydrogen to form an allylic radical. The allylic radical then reacts with bromine to form the brominated product.

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Key Concepts

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

Reaction Mechanisms

Understanding reaction mechanisms is crucial in organic chemistry as they describe the step-by-step process by which reactants transform into products. This includes identifying intermediates, transition states, and the types of bonds formed or broken during the reaction. Familiarity with common mechanisms, such as nucleophilic substitution or elimination, helps predict the major products of a reaction.

Functional Groups

Functional groups are specific groups of atoms within molecules that are responsible for the characteristic chemical reactions of those molecules. Recognizing functional groups allows chemists to predict reactivity and the types of reactions that can occur. For example, alcohols, carboxylic acids, and amines each have distinct behaviors in reactions, influencing the final products formed.

Regioselectivity

Regioselectivity refers to the preference of a chemical reaction to occur at one location over another in a molecule. This concept is essential when predicting the major product of a reaction, as certain pathways may lead to more stable or favorable products based on the structure of the reactants. Understanding regioselectivity helps in determining which isomer will be predominantly formed in a reaction.

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