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

4. Alkanes and Cycloalkanes

Naming Alkenes

Organic Chemistry

4. Alkanes and Cycloalkanes

Naming Alkenes

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6:02 minutes

Problem 44a,b

Textbook Question

Which of the following names are correct? Correct those that are not correct.
a. 4-heptyne
b. 2-ethyl-3-hexyne

Verified step by step guidance

Step 1: Recall the IUPAC rules for naming alkynes. The parent chain must be the longest continuous chain containing the triple bond, and the triple bond should receive the lowest possible locant (position number). Substituents are named and numbered based on their position relative to the parent chain.

Step 2: Analyze the name '4-heptyne'. The parent chain 'hept-' indicates seven carbons, and the '-yne' suffix indicates a triple bond. The number '4' suggests the triple bond starts at the fourth carbon. Verify if this numbering gives the lowest locant for the triple bond. If not, correct the name.

Step 3: Analyze the name '2-ethyl-3-hexyne'. The parent chain 'hex-' indicates six carbons, and the '-yne' suffix indicates a triple bond. The substituent 'ethyl' is attached at the second carbon, and the triple bond starts at the third carbon. Verify if the numbering of the parent chain gives the lowest locant for the triple bond. If not, correct the name.

Step 4: For both names, ensure that the substituents are correctly named and positioned according to IUPAC rules. If the numbering of the parent chain or substituents is incorrect, adjust the name accordingly.

Step 5: Write the corrected names (if necessary) based on the analysis above, ensuring that the triple bond and substituents are properly numbered and named according to IUPAC conventions.

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Key Concepts

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

Nomenclature of Alkynes

Alkynes are hydrocarbons that contain at least one carbon-carbon triple bond. The IUPAC naming system for alkynes involves identifying the longest carbon chain that includes the triple bond, numbering the chain to give the triple bond the lowest possible number, and using the suffix '-yne' to indicate the presence of the triple bond. Correct nomenclature is essential for clear communication in organic chemistry.

Locants in Organic Chemistry

Locants are numbers assigned to the carbon atoms in a molecule to indicate the position of functional groups or multiple bonds. In the case of alkynes, locants must be assigned to the carbon atoms involved in the triple bond, ensuring that the lowest possible numbers are used. This is crucial for accurately conveying the structure of the compound and avoiding ambiguity in its name.

Substituents in Organic Compounds

Substituents are groups of atoms that replace hydrogen atoms in a hydrocarbon chain. When naming organic compounds, substituents must be identified and named according to their position on the main carbon chain. The correct identification and naming of substituents are vital for the proper nomenclature of complex organic molecules, ensuring that the name reflects the actual structure.

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