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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3:15 minutes

Problem 24g

Textbook Question

Show how each of the following compounds can be synthesized from benzene:
g. 2-phenylpropene

Verified step by step guidance

Step 1: Begin with benzene as the starting material. To introduce a methyl group onto the benzene ring, perform a Friedel-Crafts alkylation reaction. React benzene with methyl chloride (CH₃Cl) in the presence of a Lewis acid catalyst such as aluminum chloride (AlCl₃) to form toluene (methylbenzene).

Step 2: Oxidize the methyl group on toluene to a carboxylic acid group to form benzoic acid. This can be achieved using a strong oxidizing agent such as potassium permanganate (KMnO₄) under basic conditions, followed by acidification.

Step 3: Reduce the carboxylic acid group on benzoic acid to a methyl group to form ethylbenzene. This can be done using a reducing agent such as lithium aluminum hydride (LiAlH₄) or by catalytic hydrogenation.

Step 4: Perform a halogenation reaction on ethylbenzene to introduce a halogen atom (e.g., bromine) at the benzylic position. This can be achieved using N-bromosuccinimide (NBS) in the presence of light or a radical initiator to form 1-bromo-2-phenylethane.

Step 5: Eliminate the halogen atom from 1-bromo-2-phenylethane to form 2-phenylpropene. Use a strong base such as potassium tert-butoxide (KOtBu) to perform an E2 elimination reaction, resulting in the formation of the desired alkene product.

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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, such as benzene. This reaction is crucial for synthesizing various aromatic compounds, including derivatives of benzene. Understanding EAS mechanisms, including the role of catalysts and the stability of intermediates, is essential for predicting the products formed during the synthesis of compounds like 2-phenylpropene.

Alkylation of Aromatic Compounds

Alkylation involves adding an alkyl group to an aromatic compound, which can be achieved through reactions like Friedel-Crafts alkylation. This process typically uses alkyl halides and a Lewis acid catalyst to facilitate the formation of a new carbon-carbon bond. In the synthesis of 2-phenylpropene from benzene, understanding how to effectively introduce the propene group is vital for achieving the desired product.

Rearrangement Reactions

Rearrangement reactions involve the structural reorganization of a molecule, often leading to more stable or reactive forms. In the context of synthesizing 2-phenylpropene, recognizing how intermediates can rearrange during the reaction process is important. This concept helps in understanding how to manipulate reaction conditions to favor the formation of the target compound from benzene.

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