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

12. Alcohols, Ethers, Epoxides and Thiols

Leaving Group Conversions - Sulfonyl Chlorides

Organic Chemistry

12. Alcohols, Ethers, Epoxides and Thiols

Leaving Group Conversions - Sulfonyl Chlorides

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3:16 minutes

Problem 61b

Textbook Question

Write the appropriate reagent over each arrow.

Verified step by step guidance

Step 1: Analyze the first transformation (A). The hydroxyl group (-OH) is converted into a tosylate group (-OTs). This typically involves the use of p-toluenesulfonyl chloride (TsCl) in the presence of a base such as pyridine. The base helps to neutralize the HCl byproduct formed during the reaction.

Step 2: Write the reagent for the first arrow as TsCl and pyridine. This combination facilitates the conversion of the alcohol into a tosylate, which is a good leaving group.

Step 3: Analyze the second transformation (B). The tosylate group (-OTs) is replaced by a methoxy group (-OCH₃). This substitution reaction suggests the use of a nucleophile, such as sodium methoxide (NaOCH₃) or methanol (CH₃OH) under basic conditions.

Step 4: Write the reagent for the second arrow as NaOCH₃ or CH₃OH. The nucleophile attacks the carbon attached to the tosylate group, displacing the tosylate and forming the methoxy group.

Step 5: Ensure the reaction conditions are appropriate for each step. For step A, the reaction should be carried out under mild conditions to avoid side reactions. For step B, the substitution reaction should occur in a polar aprotic solvent to favor the nucleophilic attack.

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Key Concepts

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

Alcohols and Their Reactivity

Alcohols are organic compounds containing a hydroxyl (-OH) group. They can undergo various reactions, including substitution and elimination. Understanding the reactivity of alcohols is crucial for predicting the products of reactions, such as their conversion to sulfonate esters, which are more reactive towards nucleophiles.

Sulfonyl Chlorides

Sulfonyl chlorides, such as tosyl chloride (TsCl), are reagents used to convert alcohols into better leaving groups. This transformation enhances the electrophilicity of the carbon atom bonded to the hydroxyl group, facilitating nucleophilic substitution reactions. Recognizing the role of sulfonyl chlorides is essential for understanding the mechanism of the reactions depicted in the question.

Nucleophilic Substitution Mechanisms

Nucleophilic substitution reactions involve the replacement of a leaving group by a nucleophile. There are two primary mechanisms: SN1, which is unimolecular and involves carbocation formation, and SN2, which is bimolecular and involves a direct attack by the nucleophile. Identifying the appropriate mechanism is key to determining the correct reagents for the reactions shown in the diagram.

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