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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3:26 minutes

Problem 31b

Textbook Question

In the following allylic radicals, identify the carbon where the new C― Br bond is most likely to form in the second propagation step.
(b)

Verified step by step guidance

Identify the structure of the allylic radical. An allylic radical is a radical located at the carbon atom adjacent to a double bond. This radical is stabilized by resonance.

Draw the resonance structures of the allylic radical. Resonance structures are different ways of arranging the electrons in a molecule that can help visualize the distribution of electron density.

Examine the resonance structures to determine which carbon atoms have the highest electron density. The carbon with the highest electron density is the most likely site for the formation of a new bond.

Consider the stability of the potential new C―Br bond. The bond is more likely to form at the carbon that results in the most stable product, often the one with the most substituted carbon.

Select the carbon atom where the new C―Br bond is most likely to form based on the resonance structures and stability considerations. This is typically the carbon that is most substituted or has the highest electron density in the resonance structures.

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Key Concepts

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

Allylic Radical Stability

Allylic radicals are stabilized by resonance, which allows the unpaired electron to be delocalized over multiple atoms. This delocalization increases the stability of the radical, making allylic positions more reactive in radical reactions. Understanding this stability is crucial for predicting where new bonds will form.

Resonance Structures

Resonance structures are different ways of drawing the same molecule, showing the delocalization of electrons. In allylic radicals, resonance allows the radical to be spread over several carbon atoms, influencing the site of reactivity. Identifying resonance structures helps determine the most stable and reactive positions for bond formation.

Radical Propagation Steps

Radical reactions proceed through initiation, propagation, and termination steps. In the propagation step, radicals react with other molecules to form new radicals and products. Understanding the mechanism of propagation, especially in allylic systems, is essential for predicting where new bonds, such as C-Br, will form.

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