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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3:17 minutes

Problem 2c

Textbook Question

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

Verified step by step guidance

Step 1: Identify the double bond in the structure. The double bond is located between the two carbon atoms in the upper part of the molecule.

Step 2: Assign priorities to the substituents on each carbon of the double bond using the Cahn-Ingold-Prelog priority rules. Higher atomic numbers take precedence, and if the atoms directly attached are the same, move outward to the next set of atoms.

Step 3: For the left carbon of the double bond, the substituents are the cyclopentyl group and a hydrogen atom. The cyclopentyl group has higher priority because it is a larger group compared to hydrogen.

Step 4: For the right carbon of the double bond, the substituents are the ethyl group and a hydrogen atom. The ethyl group has higher priority because it is larger than hydrogen.

Step 5: Determine the spatial arrangement of the higher-priority groups. If the higher-priority groups are on the same side of the double bond, the configuration is Z (zusammen). If they are on opposite sides, the configuration is E (entgegen).

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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 of the double bond, 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 priority rules are used to assign priorities to the substituents attached to the double bond in alkenes. The priority is determined based on atomic number; the higher the atomic number of the atom directly attached to the double bond, the higher the priority. If the first atoms are the same, the comparison continues to the next atoms in the substituent chain until a difference is found.

Stereoisomerism

Stereoisomerism refers to the phenomenon where compounds have the same molecular formula and connectivity of atoms but differ in the spatial arrangement of their atoms. In alkenes, this can lead to different physical and chemical properties, making it essential to identify whether a compound is E or Z. Understanding stereoisomerism is fundamental in organic chemistry, particularly in reactions involving alkenes.

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