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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16:52 minutes

Problem 42a,b,c

Textbook Question

Draw the condensed structure for each of the following:
a. (Z)-1,3,5-tribromo-2-pentene
b. (Z)-3-methyl-2-heptene
c. (E)-1,2-dibromo-3-isopropyl-2-hexene

Verified step by step guidance

Step 1: Understand the nomenclature and stereochemistry. The prefixes (Z) and (E) refer to the stereochemistry of the double bond. (Z) means the higher-priority groups on each carbon of the double bond are on the same side, while (E) means they are on opposite sides. Identify the substituents and their positions based on the name provided.

Step 2: For part (a), (Z)-1,3,5-tribromo-2-pentene: Start by drawing the pentene backbone (five carbons with a double bond between C2 and C3). Add bromine atoms at positions C1, C3, and C5. Ensure the (Z) configuration by placing the higher-priority groups (bromine atoms) on the same side of the double bond.

Step 3: For part (b), (Z)-3-methyl-2-heptene: Begin by drawing the heptene backbone (seven carbons with a double bond between C2 and C3). Add a methyl group at position C3. Ensure the (Z) configuration by placing the higher-priority groups (the methyl group and the longer carbon chain) on the same side of the double bond.

Step 4: For part (c), (E)-1,2-dibromo-3-isopropyl-2-hexene: Start by drawing the hexene backbone (six carbons with a double bond between C2 and C3). Add bromine atoms at positions C1 and C2, and an isopropyl group at position C3. Ensure the (E) configuration by placing the higher-priority groups (bromine atoms and the isopropyl group) on opposite sides of the double bond.

Step 5: Verify the condensed structures by ensuring all substituents are correctly placed, the stereochemistry matches the (Z) or (E) designation, and the double bond is properly represented. Condensed structures should minimize the use of explicit bonds while clearly showing the connectivity of atoms.

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Key Concepts

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

Condensed Structural Formula

A condensed structural formula is a way of representing a chemical compound that shows the arrangement of atoms and the connectivity between them without depicting all the bonds explicitly. It typically groups atoms together to indicate how they are connected, making it easier to visualize the structure of organic molecules. For example, in a condensed formula, CH3-CH2-CH=CH2 represents butene without showing every bond.

Geometric Isomerism

Geometric isomerism occurs in compounds with restricted rotation around a double bond, leading to different spatial arrangements of substituents. The terms 'Z' (from the German 'zusammen', meaning together) and 'E' (from 'entgegen', meaning opposite) are used to describe the relative positions of the highest priority substituents on either side of the double bond. Understanding this concept is crucial for accurately drawing the structures of compounds like (Z)-1,3,5-tribromo-2-pentene.

Numbering and Naming Alkenes

The IUPAC naming system for alkenes involves numbering the carbon chain to give the double bond the lowest possible number, while also considering substituents. The position of the double bond and the substituents must be indicated in the name, which helps in constructing the correct condensed structure. For instance, in (E)-1,2-dibromo-3-isopropyl-2-hexene, the numbering reflects the position of the double bond and the substituents on the hexene chain.

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