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

19. Reactions of Aromatics: EAS and Beyond

EAS:Retrosynthesis

Organic Chemistry

19. Reactions of Aromatics: EAS and Beyond

EAS:Retrosynthesis

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4:54 minutes

Problem 78a

Textbook Question

a. Describe three ways the following reaction can be carried out:

Verified step by step guidance

Step 1: Analyze the reaction. The starting material is an aromatic ketone (acetophenone derivative), and the product is an alkylated aromatic compound. This suggests that the reaction involves the reduction of the carbonyl group followed by alkylation.

Step 2: Method 1 - Use Clemmensen reduction. The Clemmensen reduction involves treating the ketone with zinc amalgam (Zn(Hg)) and concentrated hydrochloric acid (HCl). This reduces the carbonyl group to a methylene (-CH2-) group, followed by Friedel-Crafts alkylation using an alkyl halide and a Lewis acid catalyst like AlCl3.

Step 3: Method 2 - Use Wolff-Kishner reduction. The Wolff-Kishner reduction involves treating the ketone with hydrazine (N2H4) and a strong base like KOH under high heat. This reduces the carbonyl group to a methylene (-CH2-) group. After reduction, Friedel-Crafts alkylation can be performed using an alkyl halide and a Lewis acid catalyst.

Step 4: Method 3 - Direct alkylation after reduction. First, reduce the ketone using catalytic hydrogenation (H2 gas with a metal catalyst like Pd/C or Ni) to convert the carbonyl group to a methylene (-CH2-) group. Then, perform Friedel-Crafts alkylation using an alkyl halide and a Lewis acid catalyst.

Step 5: Summarize the reaction pathways. All three methods involve reducing the ketone to a methylene group followed by Friedel-Crafts alkylation to introduce the alkyl chain onto the aromatic ring. The choice of method depends on the reagents available and reaction conditions.

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Key Concepts

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

Electrophilic Aromatic Substitution (EAS)

Electrophilic Aromatic Substitution is a fundamental reaction in organic chemistry where an electrophile replaces a hydrogen atom on an aromatic ring. This process is crucial for synthesizing various aromatic compounds and involves the formation of a sigma complex, where the aromaticity is temporarily lost. Understanding the mechanism and the role of the electrophile is essential for predicting the outcome of the reaction.

Retrosynthetic Analysis

Retrosynthetic analysis is a strategy used in organic synthesis to deconstruct a target molecule into simpler precursor structures. This approach helps chemists identify potential synthetic routes by working backward from the desired product. It is particularly useful in planning multi-step syntheses and understanding how different reactions can be combined to achieve complex molecules.

Reaction Conditions and Reagents

The choice of reaction conditions and reagents significantly influences the outcome of organic reactions. Factors such as temperature, solvent, and the presence of catalysts can affect reaction rates and selectivity. In the context of EAS, different electrophiles and conditions can lead to varying substitution patterns on the aromatic ring, making it essential to understand how these variables interact in a synthetic pathway.

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