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

Fischer Projection

Organic Chemistry

5. Chirality

Fischer Projection

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1:44 minutes

Problem 20g

Textbook Question

For each pair, give the relationship between the two compounds. Making models will be helpful.
(g)

Verified step by step guidance

Step 1: Analyze the structures of the two compounds provided in the image. Both compounds are aldoses, as they contain an aldehyde group (-CHO) at the top of the structure. Additionally, they have hydroxyl (-OH) groups attached to the carbon chain.

Step 2: Compare the stereochemistry of the hydroxyl (-OH) groups at each chiral center. A chiral center is a carbon atom bonded to four different groups. In the first compound, the configuration of the hydroxyl groups alternates as HO-H, H-OH, H-OH, and CH2OH. In the second compound, the configuration alternates as H-OH, HO-H, HO-H, and CH2OH.

Step 3: Determine the relationship between the two compounds based on the stereochemistry. If the compounds differ in the configuration of all chiral centers, they are enantiomers (non-superimposable mirror images). If they differ in the configuration of some but not all chiral centers, they are diastereomers.

Step 4: Verify the configurations at each chiral center. In this case, the compounds differ in the configuration at every chiral center. For example, the first chiral center in the first compound has the hydroxyl group on the left (HO-H), while in the second compound, it is on the right (H-OH). This pattern is consistent for all chiral centers.

Step 5: Conclude that the two compounds are enantiomers because they differ in the configuration of all chiral centers and are non-superimposable mirror images of each other.

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Key Concepts

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

Fischer Projections

Fischer projections are a two-dimensional representation of three-dimensional organic molecules, particularly useful for depicting stereochemistry. In these projections, vertical lines represent bonds that extend behind the plane of the page, while horizontal lines represent bonds that come out towards the viewer. This format is especially helpful for visualizing the spatial arrangement of functional groups in carbohydrates and amino acids.

Stereoisomerism

Stereoisomerism occurs when compounds have the same molecular formula and connectivity of atoms but differ in the spatial arrangement of their atoms. This can lead to different physical and chemical properties. In the context of the provided Fischer projections, the two compounds may represent different stereoisomers, which can be classified as enantiomers or diastereomers based on their specific configurations.

Functional Groups

Functional groups are specific groups of atoms within molecules that are responsible for the characteristic chemical reactions of those molecules. In the Fischer projections shown, the presence of hydroxyl (-OH) groups and an aldehyde (-CHO) group indicates that these compounds are likely sugars or sugar derivatives. Understanding functional groups is crucial for predicting the reactivity and properties of organic compounds.

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