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

13. Alcohols and Carbonyl Compounds

Oxidizing Agent

Organic Chemistry

13. Alcohols and Carbonyl Compounds

Oxidizing Agent

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4:33 minutes

Problem 39e,f,g

Textbook Question

Predict the major products of the following reactions, including stereochemistry where appropriate.
(e) cyclopentylmethanol + Na₂Cr₂O₇/H₂SO₄
(f) cyclopentanol + HCl/ZnCl₂
(g) n-butanol + HBr

Verified step by step guidance

Step 1: For reaction (e), cyclopentylmethanol + Na₂Cr₂O₇/H₂SO₄, recognize that this is an oxidation reaction. Sodium dichromate (Na₂Cr₂O₇) in acidic conditions (H₂SO₄) is a strong oxidizing agent. Primary alcohols like cyclopentylmethanol are oxidized to carboxylic acids. Write the structure of cyclopentylmethanol and identify the hydroxyl (-OH) group attached to the carbon atom.

Step 2: In reaction (e), replace the hydrogen atoms on the carbon attached to the hydroxyl group with oxygen atoms to form a carboxylic acid. The product will be cyclopentane carboxylic acid. Ensure to maintain the cyclopentane ring structure in the product.

Step 3: For reaction (f), cyclopentanol + HCl/ZnCl₂, recognize that this is a Lucas test reaction. ZnCl₂ acts as a Lewis acid catalyst, and HCl provides the chloride ion. Secondary alcohols like cyclopentanol undergo substitution reactions to form alkyl halides. Write the structure of cyclopentanol and identify the hydroxyl (-OH) group.

Step 4: In reaction (f), the hydroxyl group (-OH) is replaced by a chloride ion (Cl⁻) to form cyclopentyl chloride. This is an SN1 reaction, so consider the formation of a carbocation intermediate. Since cyclopentanol forms a stable secondary carbocation, the reaction proceeds efficiently.

Step 5: For reaction (g), n-butanol + HBr, recognize that this is a substitution reaction where the hydroxyl group (-OH) of the primary alcohol is replaced by a bromide ion (Br⁻). Write the structure of n-butanol and identify the hydroxyl group. The reaction proceeds via an SN2 mechanism because n-butanol is a primary alcohol. Replace the -OH group with Br to form 1-bromobutane as the product.

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Key Concepts

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

Oxidation and Reduction Reactions

In organic chemistry, oxidation refers to the loss of electrons or an increase in oxidation state, often involving the addition of oxygen or the removal of hydrogen. In the context of cyclopentylmethanol reacting with Na2Cr2O7/H2SO4, this reaction leads to the oxidation of the alcohol to a ketone or carboxylic acid, depending on the conditions. Understanding the principles of oxidation is crucial for predicting the products of such reactions.

Acid-Catalyzed Reactions

Acid-catalyzed reactions, such as the reaction of cyclopentanol with HCl/ZnCl2, involve the protonation of the alcohol, making it a better leaving group. This process facilitates the conversion of alcohols to alkyl halides through nucleophilic substitution. Recognizing the role of acids in enhancing reactivity is essential for predicting the major products and their stereochemistry in these reactions.

Nucleophilic Substitution Mechanisms

Nucleophilic substitution mechanisms, such as SN1 and SN2, describe how nucleophiles replace leaving groups in organic compounds. For example, in the reaction of n-butanol with HBr, the mechanism can vary based on the substrate and conditions, leading to different products. Understanding these mechanisms is vital for predicting the outcome of reactions involving alcohols and halogen acids.