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

16. Conjugated Systems

Conjugated Hydrohalogenation (1,2 vs 1,4 addition)

Organic Chemistry

16. Conjugated Systems

Conjugated Hydrohalogenation (1,2 vs 1,4 addition)

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4:47 minutes

Problem 28c

Textbook Question

What are the products of the following reactions, assuming that one equivalent of each reagent is used in each reaction?
c.

Verified step by step guidance

Analyze the structure of the starting material: The molecule is a substituted benzene ring with an isopropyl group attached to the aromatic ring. This is known as isopropylbenzene or cumene.

Identify the reagent: Chlorine (Cl₂) is used in the reaction, and the absence of light or heat suggests that this is an electrophilic aromatic substitution reaction rather than a free radical halogenation.

Understand the mechanism: In electrophilic aromatic substitution, the chlorine molecule reacts with the aromatic ring, and one hydrogen atom is replaced by a chlorine atom. The isopropyl group is an electron-donating group, which activates the aromatic ring and directs substitution to the ortho and para positions relative to the isopropyl group.

Predict the products: Since one equivalent of chlorine is used, the reaction will yield a mixture of ortho-chlorocumene and para-chlorocumene as the major products. The meta position is less favored due to the electron-donating effect of the isopropyl group.

Consider regioselectivity: The para product is typically favored over the ortho product due to steric hindrance at the ortho position caused by the bulky isopropyl group.

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Key Concepts

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

Conjugated Systems

Conjugated systems consist of alternating single and double bonds, allowing for delocalization of π electrons. This delocalization stabilizes the molecule and can influence its reactivity. In the context of the reaction shown, the conjugated diene can undergo electrophilic addition, where reagents like Cl2 can add across the double bonds.

Electrophilic Addition

Electrophilic addition is a reaction mechanism where an electrophile reacts with a nucleophile, resulting in the addition of atoms or groups to a molecule. In this case, Cl2 acts as an electrophile that adds to the double bonds of the conjugated system, leading to the formation of vicinal dihalides. Understanding this mechanism is crucial for predicting the products 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 with Cl2, the regioselectivity will determine which carbon atoms in the conjugated system will bond with chlorine, influencing the final product's structure. This concept is essential for accurately predicting the outcome of the reaction.

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