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

5. Chirality

Constitutional Isomers vs. Stereoisomers

Organic Chemistry

5. Chirality

Constitutional Isomers vs. Stereoisomers

Previous problemNext problem

6:44 minutes

Problem 42

Textbook Question

1-Bromo-2-methylcyclopentane has four pairs of diastereomers. Draw the four pairs.

Verified step by step guidance

Understand the structure of 1-bromo-2-methylcyclopentane: It is a cyclopentane ring with a bromine atom attached to carbon-1 and a methyl group attached to carbon-2. Both substituents can have different spatial orientations (up or down) relative to the plane of the ring, leading to stereoisomers.

Recognize that the molecule has two stereocenters (carbon-1 and carbon-2). Each stereocenter can independently adopt an R or S configuration, resulting in 2^2 = 4 stereoisomers. These stereoisomers form four pairs of diastereomers.

Draw the four stereoisomers: For each stereoisomer, assign the configurations of the two stereocenters (e.g., (R,R), (R,S), (S,R), and (S,S)). Use wedge-and-dash notation to indicate the spatial orientation of the bromine and methyl groups.

Group the stereoisomers into pairs of diastereomers: Diastereomers are stereoisomers that are not mirror images of each other. For example, (R,R) and (R,S) are diastereomers, as are (S,R) and (S,S).

Verify the relationships between the stereoisomers: Confirm that each pair of diastereomers differs in the configuration of at least one stereocenter but is not a mirror image. This ensures that all four pairs of diastereomers are correctly identified.

Verified video answer for a similar problem:

This video solution was recommended by our tutors as helpful for the problem above

Video duration:

Play a video:

Was this helpful?

Key Concepts

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

Diastereomers

Diastereomers are stereoisomers that are not mirror images of each other. They occur when a molecule has multiple chiral centers, leading to different spatial arrangements of atoms. Unlike enantiomers, which have identical physical properties except for their interaction with polarized light, diastereomers can have significantly different chemical and physical properties, making their identification and separation important in organic chemistry.

Chirality and Chiral Centers

Chirality refers to the geometric property of a molecule having non-superimposable mirror images, often due to the presence of chiral centers, typically carbon atoms bonded to four different substituents. The configuration of these chiral centers can lead to the formation of different stereoisomers, including diastereomers. Understanding chirality is crucial for predicting the behavior and reactivity of organic compounds.

Drawing Stereoisomers

Drawing stereoisomers involves representing the three-dimensional arrangement of atoms in a molecule on a two-dimensional surface. This includes using wedge and dash notation to indicate bonds that are oriented towards or away from the viewer. For compounds with multiple chiral centers, it is essential to systematically vary the configurations of these centers to illustrate all possible stereoisomers, including diastereomers.

Watch next

Master Determining when molecules are different. with a bite sized video explanation from Johnny

Start learning

Related Videos

Related Practice

Textbook Question

Draw a three-dimensional structure for each compound, and star all asymmetric carbon atoms. Draw the mirror for each structure, and state whether you have drawn a pair of enantiomers or just the same molecule twice. Build molecular models of any of these examples that seem difficult to you

(a)

(b)