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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Problem 7a

Textbook Question

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

Verified step by step guidance

Step 1: Understand the E/Z nomenclature. The E/Z system is used to describe the stereochemistry of double bonds. 'E' stands for 'entgegen' (opposite sides), and 'Z' stands for 'zusammen' (same side). These configurations depend on the relative positions of the highest-priority substituents on each carbon of the double bond.

Step 2: Assign priorities to the substituents on each carbon of the double bond using the Cahn-Ingold-Prelog (CIP) priority rules. The priority is determined based on the atomic number of the atoms directly attached to the double-bonded carbons. Higher atomic numbers correspond to higher priority.

Step 3: If the substituents with the highest priority are on opposite sides of the double bond, the configuration is 'E'. If they are on the same side, the configuration is 'Z'.

Step 4: Carefully analyze the structure of the given compounds. Identify the substituents attached to each carbon of the double bond and determine their priorities using the CIP rules.

Step 5: Based on the positions of the highest-priority substituents, determine whether the compound has the E or Z configuration. Ensure you visualize or draw the molecule to confirm the spatial arrangement of the substituents.

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Key Concepts

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

E/Z Stereochemistry

E/Z stereochemistry is a system used to describe the geometric configuration 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 of the double bond, while the 'Z' (from 'Zusammen') configuration indicates that they are on the same side. This distinction is crucial for understanding the physical and chemical properties of the compounds.

Cahn-Ingold-Prelog Priority Rules

The Cahn-Ingold-Prelog (CIP) priority rules are used to assign priority to substituents attached to a double bond or chiral center. According to these rules, priority is determined by the atomic number of the atoms directly attached to the double bond; higher atomic numbers receive higher priority. If the first atoms are the same, one must consider the next atoms in the substituent chain until a difference is found.

Double Bond Geometry

The geometry of a double bond is planar due to the sp² hybridization of the carbon atoms involved, which restricts rotation. This planarity is essential for determining the E/Z configuration, as the spatial arrangement of substituents around the double bond affects the compound's reactivity and interactions. Understanding this geometry is fundamental for analyzing the stereochemical properties of alkenes.

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