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:Sequence Groups

Organic Chemistry

19. Reactions of Aromatics: EAS and Beyond

EAS:Sequence Groups

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3:52 minutes

Problem 17-20e

Textbook Question

Show how you would use the Friedel–Crafts acylation, Clemmensen reduction, and/or Gatterman–Koch synthesis to prepare the following compounds:
e. 3-methyl-1-phenylbutane

Verified step by step guidance

Step 1: Begin by analyzing the target molecule, 3-methyl-1-phenylbutane. It consists of a benzene ring attached to a butane chain with a methyl group at the 3-position. This suggests that the synthesis will involve introducing a butane chain onto the benzene ring, followed by modifications to achieve the correct branching.

Step 2: Use Friedel–Crafts acylation to introduce a butanoyl group (CH₃CH₂CH₂CO-) onto the benzene ring. This reaction involves reacting benzene with butanoyl chloride (CH₃CH₂CH₂COCl) in the presence of a Lewis acid catalyst, such as AlCl₃. The product will be 1-phenylbutan-1-one.

Step 3: Perform a Clemmensen reduction to reduce the carbonyl group (C=O) in 1-phenylbutan-1-one to a methylene group (-CH₂-). This reaction is carried out using zinc amalgam (Zn(Hg)) and concentrated hydrochloric acid (HCl). The product will be 1-phenylbutane.

Step 4: To introduce the methyl group at the 3-position, perform a free radical halogenation of 1-phenylbutane using bromine (Br₂) and light (hv) to selectively brominate the 3-position. This step will yield 3-bromo-1-phenylbutane.

Step 5: Finally, perform a nucleophilic substitution reaction (SN2) by treating 3-bromo-1-phenylbutane with a methyl nucleophile, such as sodium methoxide (CH₃ONa), to replace the bromine atom with a methyl group. This will yield the target compound, 3-methyl-1-phenylbutane.

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Key Concepts

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

Friedel–Crafts Acylation

Friedel–Crafts acylation is an electrophilic aromatic substitution reaction that introduces an acyl group into an aromatic ring. This reaction typically involves the use of an acyl chloride and a Lewis acid catalyst, such as aluminum chloride. The result is a ketone that can serve as a precursor for further transformations, making it a valuable method for synthesizing substituted aromatic compounds.

Clemmensen Reduction

The Clemmensen reduction is a chemical reaction that reduces carbonyl groups (aldehydes and ketones) to alkanes using zinc amalgam and hydrochloric acid. This method is particularly useful for converting aromatic ketones into their corresponding alkylated products, allowing for the formation of hydrocarbons from more complex structures. It is essential for synthesizing compounds where the carbonyl functionality needs to be removed.

Gatterman–Koch Synthesis

The Gatterman–Koch synthesis is a method for synthesizing aromatic aldehydes through the formylation of aromatic compounds using carbon monoxide and hydrochloric acid in the presence of a Lewis acid catalyst. This reaction is significant for introducing formyl groups into aromatic systems, which can then be further manipulated to create various substituted aromatic compounds, aiding in the construction of complex organic molecules.

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