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

9. Alkenes and Alkynes

Hydrogenation of Alkynes

Organic Chemistry

9. Alkenes and Alkynes

Hydrogenation of Alkynes

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2:22 minutes

Problem 34a

Textbook Question

What reagents should be used to carry out the following syntheses?

Verified step by step guidance

To convert an alkyne (RC≡CH) to an alkane (RCH₂CH₃), use hydrogen gas (H₂) with a palladium catalyst (Pd/C) for complete hydrogenation.

To convert an alkyne (RC≡CH) to an alkene (RCH=CH₂), use hydrogen gas (H₂) with a Lindlar's catalyst to achieve syn-addition and stop at the alkene stage.

To convert an alkyne (RC≡CH) to a bromoalkene (RCH=CHBr), use hydrogen bromide (HBr) in the presence of a peroxide to achieve anti-Markovnikov addition.

To convert an alkyne (RC≡CH) to a ketone (RCCH₃), use water (H₂O) with a mercury(II) sulfate (HgSO₄) catalyst in an acidic medium (H₂SO₄) for hydration via Markovnikov addition.

To convert an alkyne (RC≡CH) to an aldehyde (RCH₂CHO), use hydroboration-oxidation with reagents such as disiamylborane followed by hydrogen peroxide (H₂O₂) and sodium hydroxide (NaOH) for anti-Markovnikov addition.

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Key Concepts

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

Alkyne Reactivity

Alkynes, characterized by a carbon-carbon triple bond, exhibit unique reactivity patterns. They can undergo various reactions such as hydrogenation, halogenation, and hydration. Understanding these reactions is crucial for predicting the products formed when specific reagents are applied to alkynes in synthetic pathways.

Electrophilic Addition Reactions

Electrophilic addition reactions involve the addition of electrophiles to nucleophilic sites in unsaturated hydrocarbons like alkenes and alkynes. In the context of the question, recognizing how reagents such as bromine or water can add across the triple bond of an alkyne is essential for determining the correct synthetic route and products.

Functional Group Transformations

Functional group transformations refer to the chemical reactions that convert one functional group into another. In organic synthesis, this concept is vital for understanding how to manipulate starting materials to achieve desired products, such as converting alkynes into alcohols or carbonyl compounds through specific reagents and reaction conditions.

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