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

Cis vs Trans

Organic Chemistry

4. Alkanes and Cycloalkanes

Cis vs Trans

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1:53 minutes

Problem 2b

Textbook Question

Identify the following alkenes as E or Z, if appropriate.
(b)

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Examine the structure of the alkene provided. The molecule is a cyclic alkene with a double bond in an 8-membered ring.

Determine the substituents attached to the double bond. In this case, the double bond is part of the ring, and the substituents are the two halves of the ring.

Apply the Cahn-Ingold-Prelog priority rules to assign priorities to the groups attached to the double bond. For cyclic alkenes, the priority is determined by the size and connectivity of the ring segments.

Check the spatial arrangement of the higher-priority groups on each side of the double bond. If the higher-priority groups are on the same side, the configuration is Z (zusammen, German for 'together'). If they are on opposite sides, the configuration is E (entgegen, German for 'opposite').

Conclude whether the alkene is E or Z based on the analysis. For cyclic alkenes, the geometry is often constrained by the ring size, which can influence the configuration.

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Key Concepts

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

E/Z Configuration

E/Z configuration is a method used to describe the stereochemistry of alkenes based on the priority of substituents attached to the double bond. The 'E' (entgegen) designation indicates that the highest priority groups are on opposite sides, while 'Z' (zusammen) indicates they are on the same side. This system is crucial for understanding the geometric isomerism in alkenes.

Cahn-Ingold-Prelog Priority Rules

The Cahn-Ingold-Prelog (CIP) priority rules are used to assign priority to substituents based on atomic number and connectivity. The atom with the higher atomic number gets higher priority. If the first atoms are the same, the priority is determined by the next atoms in the substituent chain. This is essential for determining E/Z configurations accurately.

Cycloalkenes

Cycloalkenes are cyclic hydrocarbons that contain at least one carbon-carbon double bond. The ring structure can influence the spatial arrangement of substituents, making the identification of E/Z configurations particularly important. Understanding the geometry of cycloalkenes is key to analyzing their stereochemistry and reactivity.

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