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

Williamson Ether Synthesis

Organic Chemistry

12. Alcohols, Ethers, Epoxides and Thiols

Williamson Ether Synthesis

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7:30 minutes

Problem 41a

Textbook Question

Design a synthesis for each of the following, using an intramolecular reaction:
a.

Verified step by step guidance

Analyze the target molecule: The structure provided is a six-membered cyclic ether (tetrahydropyran) with two methyl groups attached to the ring. This suggests the use of an intramolecular reaction to form the cyclic ether.

Select a precursor molecule: To form the cyclic ether via an intramolecular reaction, choose a molecule with both an alcohol (-OH) group and a leaving group (e.g., halide or tosylate) positioned appropriately for cyclization.

Plan the intramolecular reaction: The reaction mechanism likely involves nucleophilic substitution (SN2) or elimination followed by ring closure. The alcohol group will act as the nucleophile, attacking the electrophilic carbon attached to the leaving group.

Ensure proper functional group placement: Design the precursor molecule such that the alcohol and leaving group are separated by the correct number of carbons to form a six-membered ring upon cyclization. For example, a 6-carbon chain with an alcohol at one end and a halide at the other end would work.

Propose reaction conditions: Use a base (e.g., NaH or KOH) to deprotonate the alcohol, increasing its nucleophilicity. Heat the reaction mixture to promote cyclization and form the tetrahydropyran ring.

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Key Concepts

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

Intramolecular Reactions

Intramolecular reactions occur when a reaction takes place within a single molecule, leading to the formation of a cyclic structure. This type of reaction often involves the nucleophilic attack of a functional group on another part of the same molecule, resulting in the closure of a ring. Understanding intramolecular reactions is crucial for designing syntheses that yield cyclic compounds, as they can significantly influence the reaction pathway and product formation.

Williamson Ether Synthesis

Williamson Ether Synthesis is a method for creating ethers through the reaction of an alkoxide ion with a primary alkyl halide. This reaction typically involves a nucleophilic substitution mechanism (SN2), where the alkoxide acts as a nucleophile and attacks the electrophilic carbon of the alkyl halide. This concept is essential for the synthesis of cyclic ethers, as it provides a pathway to form ethers that can be further manipulated in intramolecular reactions.

Cyclic Ethers

Cyclic ethers are a class of compounds characterized by a ring structure containing one or more ether linkages (–O–). They are often formed through intramolecular reactions and can exhibit unique chemical properties due to their ring strain and reactivity. Understanding the structure and reactivity of cyclic ethers is vital for predicting the outcomes of synthetic routes and for designing effective synthesis strategies in organic chemistry.

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Related Practice

Textbook Question

Show how you would synthesize the following ethers in good yield from the indicated starting materials and any additional reagents needed.

(b) n-butyl phenyl ether from phenol and butan-1-ol

Textbook Question

Both LiAlH₄ and Grignard reagents react with carbonyl compounds to give alkoxide ion intermediates (that become protonated in an aqueous workup). Those alkoxides can react with 1° or methyl alkyl halides or tosylates to give ethers. Show how the following ethers can be formed in this two-step process. As starting materials you may use any reactants containing 7 carbons or fewer.

(b)

Textbook Question

(c)

Textbook Question

In Chapter 14, we saw that Agent Orange contains (2,4,5-trichlorophenoxy) acetic acid, called 2,4,5-T. This compound is synthesized by the partial reaction of 1,2,4,5-tetrachlorobenzene with sodium hydroxide, followed by reaction with sodium chloroacetate, ClCH₂CO₂Na.

a. Draw the structures of these compounds, and write equations for these reactions.

Textbook Question

Predict the products formed when m-cresol (m-methylphenol) reacts with

(a) NaOH and then ethyl bromide

Multiple Choice

Which synthesis would be best to make the following target?

Multiple Choice

Which of the following will successfully synthesize the given target?

Multiple Choice

Predict the major, organic product for the following reaction.

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