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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4:32 minutes

Problem 80

Textbook Question

Propose a mechanism to explain how dimethyl sulfoxide and oxalyl chloride react to form the dimethylchlorosulfonium ion used as the oxidizing agent in the Swern oxidation.

Verified step by step guidance

Step 1: Begin by recognizing that dimethyl sulfoxide (DMSO) acts as a nucleophile due to the lone pair on the sulfur atom. Oxalyl chloride, a reactive electrophile, reacts with DMSO by allowing the sulfur atom to attack one of the carbonyl carbons of oxalyl chloride, leading to the formation of a tetrahedral intermediate.

Step 2: The tetrahedral intermediate collapses, expelling a molecule of carbon dioxide (CO₂) and a molecule of carbon monoxide (CO). This results in the formation of a chlorodimethylsulfonium ion, where the sulfur atom is now positively charged and bonded to a chlorine atom.

Step 3: The chlorodimethylsulfonium ion is highly electrophilic and serves as the oxidizing agent in the Swern oxidation. It reacts with the alcohol substrate (e.g., propan-2-ol) by facilitating the formation of an alkoxysulfonium intermediate.

Step 4: Triethylamine, a base, is introduced to deprotonate the alkoxysulfonium intermediate, leading to the formation of a ketone (e.g., acetone) and dimethyl sulfide as the final products.

Step 5: The overall reaction mechanism highlights the role of dimethyl sulfoxide and oxalyl chloride in generating the reactive chlorodimethylsulfonium ion, which is essential for the oxidation of alcohols to carbonyl compounds in the Swern oxidation.

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Key Concepts

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

Swern Oxidation

Swern oxidation is a method for converting alcohols into carbonyl compounds using dimethyl sulfoxide (DMSO) and an activating agent, typically oxalyl chloride. The process involves the formation of a chlorosulfide intermediate, which subsequently reacts with the alcohol to yield the desired carbonyl compound. This reaction is notable for its mild conditions and high selectivity.

Dimethyl Sulfoxide (DMSO)

Dimethyl sulfoxide is a polar aprotic solvent widely used in organic synthesis. It acts as a reagent in various reactions, including the Swern oxidation, where it facilitates the formation of reactive intermediates. DMSO can stabilize positive charges, making it effective in promoting nucleophilic attacks and enhancing reaction rates.

Chlorodimethylsulfonium Ion

The chlorodimethylsulfonium ion is a key intermediate in the Swern oxidation mechanism. It is formed when DMSO reacts with oxalyl chloride, resulting in a sulfonium ion that can act as an electrophile. This ion is crucial for the subsequent reaction with alcohols, leading to the formation of the oxidizing agent, dimethylchlorosulfonium, which facilitates the oxidation process.

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