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 - SOCl2 and PBr3

Organic Chemistry

12. Alcohols, Ethers, Epoxides and Thiols

Leaving Group Conversions - SOCl2 and PBr3

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Problem 106a(i,ii)

Textbook Question

Predict the product(s) that would result when molecules (a)–(p) are allowed to react under the following conditions: (i) SOCl₂ ; (ii) PBr₃. If no reaction occurs, write 'no reaction.'
(a)

Verified step by step guidance

Identify the functional group in the given molecule. The structure shown is benzyl alcohol, which contains a hydroxyl group (-OH) attached to a benzyl group.

Consider the reaction with thionyl chloride (SOCl₂). Thionyl chloride is commonly used to convert alcohols into alkyl chlorides. The hydroxyl group will be replaced by a chlorine atom.

Write the mechanism for the reaction with SOCl₂. The reaction typically involves the formation of an intermediate chlorosulfite ester, followed by the release of sulfur dioxide (SO₂) and hydrogen chloride (HCl), resulting in the formation of benzyl chloride.

Consider the reaction with phosphorus tribromide (PBr₃). PBr₃ is used to convert alcohols into alkyl bromides. The hydroxyl group will be replaced by a bromine atom.

Write the mechanism for the reaction with PBr₃. The reaction involves the formation of an intermediate dibromophosphite ester, followed by the release of phosphorous acid (H₃PO₃), resulting in the formation of benzyl bromide.

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Key Concepts

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

Thionyl Chloride (SOCl₂) Reactivity

Thionyl chloride is a reagent commonly used for converting alcohols into alkyl chlorides. The reaction proceeds through the formation of an intermediate that facilitates the substitution of the hydroxyl group with a chlorine atom. Understanding the mechanism of this reaction, including the role of the leaving group and the formation of byproducts like sulfur dioxide and hydrochloric acid, is essential for predicting the products.

Phosphorus Tribromide (PBr₃) Reactivity

Phosphorus tribromide is another reagent used to convert alcohols into alkyl bromides. The mechanism involves the formation of an intermediate that allows for the substitution of the hydroxyl group with a bromine atom. Recognizing the conditions under which PBr₃ operates, including its preference for primary and secondary alcohols, is crucial for determining the expected products of the reaction.

Substitution Reactions

Substitution reactions are fundamental organic reactions where one functional group is replaced by another. In the context of alcohols reacting with SOCl₂ and PBr₃, the hydroxyl group is substituted by a halogen. Understanding the types of substitution mechanisms, such as SN1 and SN2, helps in predicting the outcome of reactions based on the structure of the starting materials and the conditions provided.

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