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

14. Synthetic Techniques

Alkynide Alkylation

Organic Chemistry

14. Synthetic Techniques

Alkynide Alkylation

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7: minutes

Problem 28b

Textbook Question

How could the following compounds be synthesized from acetylene?
b.

Verified step by step guidance

Step 1: Begin by understanding the structure of acetylene (C₂H₂), which is a simple alkyne with a triple bond between two carbon atoms. Acetylene is a versatile starting material in organic synthesis due to its reactivity.

Step 2: Identify the target compound (b) and analyze its functional groups and carbon skeleton. Determine the transformations required to convert acetylene into the desired compound, such as chain elongation, addition reactions, or functional group modifications.

Step 3: Use acetylene's reactivity with electrophiles to introduce new groups. For example, acetylene can undergo hydrohalogenation (addition of HX) to form haloalkenes or halides, or hydration (addition of H₂O in the presence of HgSO₄ and H₂SO₄) to form ketones.

Step 4: If chain elongation is required, consider reactions such as alkylation. Acetylene can be deprotonated using a strong base (e.g., NaNH₂) to form an acetylide ion, which can then react with alkyl halides to extend the carbon chain.

Step 5: Perform additional functional group transformations as needed. For example, reduction (using H₂ and a catalyst) can convert triple bonds to double or single bonds, and oxidation reactions can introduce oxygen-containing groups. Tailor the sequence of reactions to achieve the desired compound.

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Key Concepts

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

Acetylene Reactivity

Acetylene (C2H2) is a highly reactive alkyne that can undergo various reactions, including addition reactions with electrophiles. Understanding its reactivity is crucial for synthesizing more complex compounds. The triple bond in acetylene makes it a good nucleophile, allowing it to react with halogens, hydrogen halides, and other reagents to form different functional groups.

Functional Group Transformations

Functional group transformations involve converting one functional group into another through chemical reactions. In the context of synthesizing compounds from acetylene, it is essential to know how to manipulate the existing functional groups or introduce new ones. This includes reactions like hydrogenation, halogenation, and hydroboration, which can modify the structure and reactivity of the starting material.

Synthetic Pathways

Synthetic pathways refer to the step-by-step sequences of reactions used to convert starting materials into desired products. For synthesizing compounds from acetylene, it is important to outline a logical pathway that includes all necessary reactions and intermediates. This involves selecting appropriate reagents and conditions to achieve the desired transformations efficiently and effectively.

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Related Practice

Textbook Question

Show how each of the following compounds can be synthesized from the given starting materials:

Textbook Question

Predict the products formed when CH₃CH₂–C≡C:^–Na⁺ reacts with the following compounds.

(d) cyclohexanone

(e) CH₃CH₂CH₂CHO

Textbook Question

The application box in the margin of states, “The addition of an acetylide ion to a carbonyl group is used in the synthesis of ethchlorvynol, a drug used to cause drowsiness and induce sleep.” Show how you would accomplish this synthesis from acetylene and a carbonyl compound.

Textbook Question

Show how the following compounds can be prepared, using ethyne as one of the starting materials:

1. 1-pentyn-3-ol

Textbook Question

Reaction of the acetylide with the epoxide shown will not form the desired product. What side reaction occurs instead? Why?

Textbook Question

Beginning with the molecules on the left of each chemical equation, synthesize the molecules shown. While there can be multiple ways of doing each synthesis, the minimum number of steps necessary is indicated over each reaction arrow.

(b)

Textbook Question

Beginning with the molecules on the left, provide a synthesis of the molecule on the right. The ideal number of steps is indicated over the reaction arrow, although there may be alternate routes worth considering.

(b)

Textbook Question

Synthesize the following molecules beginning with only organic molecules containing three carbons or fewer.

(b)

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