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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3:11 minutes

Problem 13a

Textbook Question

Given the name, draw the structure of the following alkenes.
(a) (E)-4-ethyl-5-methyloct-3-ene

Verified step by step guidance

Step 1: Understand the nomenclature. The name '(E)-4-ethyl-5-methyloct-3-ene' provides information about the structure of the molecule. The 'oct' indicates an 8-carbon chain, '3-ene' specifies a double bond at the 3rd carbon, and the '(E)' configuration means the substituents on the double bond are on opposite sides.

Step 2: Begin by drawing the parent chain. Draw a straight chain of 8 carbons (octane backbone). Number the carbons from 1 to 8, ensuring the double bond starts at the 3rd carbon.

Step 3: Add the substituents. At carbon 4, attach an ethyl group (CH₂CH₃). At carbon 5, attach a methyl group (CH₃). Ensure the substituents are correctly positioned based on the numbering.

Step 4: Apply the (E) configuration to the double bond. For the double bond at carbon 3, arrange the substituents such that the higher-priority groups (based on Cahn-Ingold-Prelog rules) are on opposite sides of the double bond.

Step 5: Verify the structure. Check that the molecule has the correct number of carbons, substituents, and the double bond is in the correct position with the specified stereochemistry.

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Key Concepts

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

Alkene Structure

Alkenes are hydrocarbons that contain at least one carbon-carbon double bond (C=C). The presence of this double bond affects the geometry and reactivity of the molecule. Understanding the basic structure of alkenes is crucial for drawing their representations, as it dictates the arrangement of atoms and the overall shape of the molecule.

E/Z Stereochemistry

E/Z stereochemistry is a system used to describe the spatial arrangement of substituents around a double bond. The 'E' (entgegen) configuration indicates that the highest priority substituents on each carbon of the double bond are on opposite sides, while 'Z' (zusammen) indicates they are on the same side. This distinction is essential for accurately representing the geometry of alkenes in structural drawings.

Nomenclature of Organic Compounds

The IUPAC nomenclature system provides a standardized way to name organic compounds based on their structure. In the case of (E)-4-ethyl-5-methyloct-3-ene, the name indicates the longest carbon chain (oct-3-ene), the position of the double bond, and the substituents (ethyl and methyl) along with their respective positions. Familiarity with nomenclature rules is vital for interpreting names and translating them into structural formulas.

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