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

Previous problemNext problem

3:18 minutes

Problem 39a,b

Textbook Question

Predict the major products of the following reactions, including stereochemistry where appropriate.
(a) (R)-butan-2-ol + TsCl in pyridine
(b) (S)-2-butyl tosylate + NaBr

Verified step by step guidance

Step 1: Analyze the first reaction (a). The reaction involves (R)-butan-2-ol reacting with tosyl chloride (TsCl) in pyridine. This is a tosylation reaction, where the hydroxyl group (-OH) of the alcohol is converted into a tosylate group (-OTs). The pyridine acts as a base to neutralize the HCl byproduct. The stereochemistry of the carbon center remains unchanged during this step, so the product will be (R)-2-butyl tosylate.

Step 2: Write the chemical equation for reaction (a). The structure of (R)-butan-2-ol is CH₃-CH(OH)-CH₂-CH₃, and the product will be CH₃-CH(OTs)-CH₂-CH₃. The stereochemistry at the chiral center (C2) remains (R).

Step 3: Analyze the second reaction (b). The reaction involves (S)-2-butyl tosylate reacting with NaBr. This is a nucleophilic substitution reaction (SN2 mechanism) because the tosylate group (-OTs) is a good leaving group, and bromide ion (Br⁻) is a strong nucleophile. In an SN2 reaction, the nucleophile attacks the electrophilic carbon from the opposite side of the leaving group, resulting in an inversion of configuration at the chiral center.

Step 4: Write the chemical equation for reaction (b). The structure of (S)-2-butyl tosylate is CH₃-CH(OTs)-CH₂-CH₃. The bromide ion (Br⁻) will replace the tosylate group, forming CH₃-CH(Br)-CH₂-CH₃. Due to the inversion of configuration, the product will have the (R)-configuration at the chiral center.

Step 5: Summarize the major products. For reaction (a), the product is (R)-2-butyl tosylate. For reaction (b), the product is (R)-2-bromobutane. Ensure to include stereochemistry in your final answer, as it is critical for understanding the outcome of these reactions.

Verified video answer for a similar problem:

This video solution was recommended by our tutors as helpful for the problem above

Video duration:

Play a video:

Was this helpful?

Key Concepts

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

Tosylation

Tosylation is the process of converting an alcohol into a tosylate using tosyl chloride (TsCl) in the presence of a base like pyridine. This reaction transforms the alcohol into a better leaving group, facilitating subsequent nucleophilic substitution reactions. The resulting tosylate retains the stereochemistry of the original alcohol, which is crucial for predicting the products in further reactions.

Nucleophilic Substitution Reactions

Nucleophilic substitution reactions involve the replacement of a leaving group by a nucleophile. In the case of the reaction between 2-butyl tosylate and NaBr, the bromide ion acts as the nucleophile, attacking the carbon atom bonded to the tosylate group. The mechanism can be either SN1 or SN2, depending on the substrate structure and conditions, which influences the stereochemistry of the product.

Stereochemistry

Stereochemistry refers to the spatial arrangement of atoms in molecules and how this affects their chemical behavior. In reactions involving chiral centers, such as those with butan-2-ol and its derivatives, the stereochemistry of the reactants must be considered to predict the stereochemical outcome of the products. Understanding whether a reaction proceeds via an inversion of configuration or retention is essential for accurate product prediction.

Watch next

Master Learning the mechanism of Sulfonyl Chlorides. with a bite sized video explanation from Johnny

Start learning