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

10. Addition Reactions

Epoxide Reactions

Organic Chemistry

10. Addition Reactions

Epoxide Reactions

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3:43 minutes

Problem 60d

Textbook Question

What is the major product obtained from the reaction of 2-ethyloxirane with each of the following reagents?
d. CH₃OH/CH₃O^-

Verified step by step guidance

Identify the structure of 2-ethyloxirane. It is a three-membered cyclic ether (epoxide) with an ethyl group attached to one of the carbons in the ring.

Understand the reactivity of epoxides. Epoxides are highly strained and reactive, and they undergo ring-opening reactions in the presence of nucleophiles. The reaction can proceed under basic or acidic conditions. In this case, CH3O- (methoxide) is a strong nucleophile, and the reaction occurs under basic conditions.

Determine the regioselectivity of the reaction. Under basic conditions, the nucleophile (CH3O-) attacks the less substituted carbon of the epoxide due to steric hindrance. This results in the opening of the epoxide ring.

Write the mechanism of the reaction. The methoxide ion (CH3O-) attacks the less substituted carbon of the epoxide, breaking the C-O bond and forming an alkoxide intermediate. The intermediate is then protonated by CH3OH (methanol), yielding the final product.

Draw the major product. The product will be a molecule where the methoxy group (-OCH3) is attached to the less substituted carbon of the original epoxide, and the hydroxyl group (-OH) is attached to the more substituted carbon.

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Key Concepts

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

Epoxide Reactivity

Epoxides, or oxiranes, are three-membered cyclic ethers that are highly reactive due to the strain in their ring structure. They can undergo nucleophilic ring-opening reactions, where a nucleophile attacks one of the carbon atoms in the epoxide, leading to the formation of a more stable product. The nature of the nucleophile and the reaction conditions can significantly influence the regioselectivity and stereochemistry of the resulting product.

Nucleophilic Substitution

Nucleophilic substitution is a fundamental reaction mechanism in organic chemistry where a nucleophile replaces a leaving group in a molecule. In the case of epoxides, the nucleophile attacks the less hindered carbon atom, leading to the opening of the epoxide ring. The choice of nucleophile, such as methanol (CH3OH) in this question, determines the nature of the product formed, often resulting in the formation of an alcohol.

Regioselectivity

Regioselectivity refers to the preference of a chemical reaction to yield one structural isomer over others when multiple possibilities exist. In the context of epoxide reactions, the regioselectivity is influenced by steric and electronic factors, which dictate which carbon atom in the epoxide is attacked by the nucleophile. Understanding regioselectivity is crucial for predicting the major product in reactions involving epoxides and various nucleophiles.

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