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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1:33 minutes

Problem 70e

Textbook Question

Do the following compounds have the E or the Z configuration?
e.

Verified step by step guidance

Step 1: Identify the double bond in the compound. The E/Z configuration applies to alkenes (compounds with a carbon-carbon double bond). Locate the double bond in the structure provided.

Step 2: Assign priorities to the groups attached to each carbon of the double bond using the Cahn-Ingold-Prelog (CIP) priority rules. These rules state that the group with the higher atomic number gets the higher priority. If the first atoms are the same, move to the next atoms in the chain until a difference is found.

Step 3: Determine the relative positions of the higher-priority groups on each carbon of the double bond. If the higher-priority groups are on the same side of the double bond, the configuration is Z (from the German word 'zusammen,' meaning 'together'). If they are on opposite sides, the configuration is E (from the German word 'entgegen,' meaning 'opposite').

Step 4: Verify your assignments by carefully checking the structure and ensuring that the priorities were assigned correctly and the spatial arrangement of the groups is accurately interpreted.

Step 5: Label the compound with the correct configuration (E or Z) based on your analysis. If there are multiple double bonds, repeat the process for each one and specify the configuration for each double bond.

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Key Concepts

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

Cis-Trans Isomerism

Cis-trans isomerism, also known as geometric isomerism, occurs in compounds with restricted rotation around a double bond or a ring structure. In this context, 'cis' refers to substituents being on the same side of the double bond, while 'trans' indicates they are on opposite sides. Understanding this concept is crucial for determining the E/Z configuration of alkenes.

E/Z Configuration

The E/Z nomenclature is used to describe the stereochemistry of alkenes based on the priority of substituents attached to the double bond. The 'E' (from the German 'Entgegen') configuration indicates that the highest priority groups are on opposite sides, while 'Z' (from 'Zusammen') indicates they are on the same side. This system is essential for accurately describing the spatial arrangement of atoms in a molecule.

Cahn-Ingold-Prelog Priority Rules

The Cahn-Ingold-Prelog (CIP) priority rules are a set of guidelines used to assign priority to substituents based on atomic number and connectivity. According to these rules, the atom with the higher atomic number receives higher priority. These priorities are critical for determining whether a compound is classified as E or Z, as they dictate the arrangement of substituents around the double bond.

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