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

Reducing Agent

Organic Chemistry

13. Alcohols and Carbonyl Compounds

Reducing Agent

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3:41 minutes

Problem 102a

Textbook Question

Propose a mechanism for the following reaction:

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Step 1: Analyze the reaction. The starting material is a ketone (2,6-dimethylcyclohex-2-enone), and the product is a phenol (2,6-dimethylphenol). The reaction involves acid-catalyzed aromatization, facilitated by H₂SO₄.

Step 2: Protonation of the ketone. The sulfuric acid (H₂SO₄) donates a proton (H⁺) to the carbonyl oxygen of the ketone, forming a protonated intermediate. This increases the electrophilicity of the carbonyl carbon.

Step 3: Enol formation. A tautomerization occurs where the protonated ketone undergoes enolization. The α-hydrogen adjacent to the carbonyl group is removed, and the double bond shifts to form an enol intermediate.

Step 4: Aromatization. The enol intermediate undergoes a series of proton transfers and elimination reactions to form the aromatic ring. This involves the loss of water and the formation of a conjugated π-system, resulting in the phenol structure.

Step 5: Deprotonation. The final step involves the removal of the proton from the hydroxyl group by the conjugate base of H₂SO₄, yielding the neutral phenol product (2,6-dimethylphenol).

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Key Concepts

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

Reaction Mechanism

A reaction mechanism is a step-by-step description of how a chemical reaction occurs at the molecular level. It outlines the sequence of elementary steps, including bond breaking and formation, and the intermediates formed during the reaction. Understanding the mechanism is crucial for predicting the products and the conditions under which the reaction occurs.

Nucleophiles and Electrophiles

Nucleophiles are species that donate an electron pair to form a chemical bond, while electrophiles are electron-deficient species that accept an electron pair. Identifying these species in a reaction is essential for proposing a mechanism, as it helps to determine the direction of electron flow and the nature of the reaction intermediates.

Transition States and Intermediates

Transition states are high-energy states that occur during the transformation of reactants to products, representing the point of maximum energy along the reaction pathway. Intermediates are species that are formed and consumed during the reaction but are not present in the final products. Understanding these concepts is vital for accurately depicting the mechanism and predicting the reaction's rate and outcome.

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Related Practice

Textbook Question

Both NaBH₄ and NaBD₄ are commercially available, and D₂O is common and inexpensive. Show how you would synthesize the following labeled compounds, starting with butan-2-one.

(a)

Textbook Question

Suggest the most appropriate reagent for each synthesis, and explain your choice.

(c)

Textbook Question

Sodium triacetoxyborohydride, NaBH(OAc)₃, is a mild reducing agent that reduces aldehydes much more quickly than ketones. It can be used to reduce aldehydes in the presence of ketones, such as in the following reaction:

(a) Draw a complete Lewis structure for sodium triacetoxyborohydride.

Textbook Question

Draw the products of the following reactions. Indicate whether each reaction is an oxidation or a reduction.

Textbook Question

Predict the product of the following reaction sequences.

(c)

Textbook Question

Show how you would synthesize the following compounds from the appropriate carboxylic acids or acid derivatives.

Textbook Question

How can the following compounds be prepared from the given starting materials?

Multiple Choice

What is the product of the reaction?