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

14. Synthetic Techniques

Alkane Halogenation

Organic Chemistry

14. Synthetic Techniques

Alkane Halogenation

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4:17 minutes

Problem 56a,b,c

Textbook Question

Using cyclohexane as your starting material, show how you would synthesize each of the following compounds. (Once you have shown how to synthesize a compound, you may use it as the starting material in any later parts of this problem.)
a. bromocyclohexane
b. cyclohexene
c. ethoxycyclohexane

Verified step by step guidance

Step 1: To synthesize bromocyclohexane (compound a) from cyclohexane, perform a free radical halogenation reaction. Use bromine (Br₂) in the presence of ultraviolet (UV) light or heat to initiate the reaction. This will result in the substitution of one hydrogen atom on cyclohexane with a bromine atom, forming bromocyclohexane.

Step 2: To synthesize cyclohexene (compound b) from bromocyclohexane, perform an elimination reaction. Use a strong base, such as potassium tert-butoxide (KOtBu) or sodium ethoxide (NaOEt), in an alcohol solvent. The base will abstract a β-hydrogen, leading to the formation of a double bond and producing cyclohexene.

Step 3: To synthesize ethoxycyclohexane (compound c) from cyclohexene, perform an electrophilic addition reaction. First, react cyclohexene with ethanol (C₂H₅OH) in the presence of an acid catalyst, such as sulfuric acid (H₂SO₄). This will result in the addition of an ethoxy group (-OCH₂CH₃) to the cyclohexane ring, forming ethoxycyclohexane.

Step 4: Ensure that each reaction is carried out under the appropriate conditions (e.g., temperature, solvent, and catalyst) to maximize yield and minimize side reactions. For example, control the amount of bromine in Step 1 to avoid over-halogenation.

Step 5: Verify the structures of the synthesized compounds using spectroscopic techniques such as NMR or IR spectroscopy to confirm the success of each reaction.

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Key Concepts

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

Electrophilic Substitution

Electrophilic substitution is a fundamental reaction mechanism in organic chemistry where an electrophile replaces a hydrogen atom in an aromatic or aliphatic compound. In the case of synthesizing bromocyclohexane from cyclohexane, bromine acts as the electrophile, and the reaction typically requires a catalyst, such as iron(III) bromide, to facilitate the substitution process.

Elimination Reactions

Elimination reactions involve the removal of atoms or groups from a molecule, resulting in the formation of a double bond. To synthesize cyclohexene from cyclohexane, a common method is dehydrohalogenation, where a halogen and a hydrogen atom are removed, often using a strong base like potassium hydroxide, leading to the formation of the alkene.

Nucleophilic Substitution

Nucleophilic substitution is a reaction where a nucleophile replaces a leaving group in a molecule. In the synthesis of ethoxycyclohexane, cyclohexanol can be reacted with ethyl bromide in the presence of a base, allowing the ethoxy group to substitute for the hydroxyl group, resulting in the formation of the ether.

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