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

R and S Configuration

Organic Chemistry

5. Chirality

R and S Configuration

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3:51 minutes

Problem 30

Textbook Question

What is the configuration about each of the asymmetric centers in aspartame?

Verified step by step guidance

Identify the asymmetric centers in aspartame. Aspartame is a dipeptide composed of aspartic acid and phenylalanine methyl ester. Look for carbon atoms that are bonded to four different groups, as these are the chiral centers.

Label the asymmetric centers. In aspartame, there are two chiral centers: one in the aspartic acid portion (the α-carbon) and one in the phenylalanine portion (the α-carbon).

Assign priorities to the groups attached to each chiral center using the Cahn-Ingold-Prelog (CIP) priority rules. These rules prioritize groups based on the atomic number of the atoms directly attached to the chiral center. If two atoms are the same, move outward to the next set of atoms until a difference is found.

Determine the configuration (R or S) for each chiral center. Orient the molecule so that the group with the lowest priority is pointing away from you. Then, trace a path from the highest priority group (1) to the second (2) and third (3). If the path is clockwise, the configuration is R; if counterclockwise, it is S.

Repeat the process for both chiral centers in aspartame. Carefully analyze the groups attached to each center and assign the correct configuration for each one.

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Key Concepts

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

Asymmetric Centers

Asymmetric centers, or chiral centers, are carbon atoms bonded to four different substituents, leading to non-superimposable mirror images known as enantiomers. In organic molecules, the configuration of these centers is crucial for determining the molecule's stereochemistry and biological activity. Understanding how to identify and describe these centers is essential for analyzing compounds like aspartame.

Stereochemistry

Stereochemistry is the study of the spatial arrangement of atoms in molecules and how this arrangement affects their chemical properties and reactions. It encompasses concepts such as chirality, enantiomers, and diastereomers. For aspartame, knowing the stereochemical configuration of its asymmetric centers is vital for understanding its sweetness and interaction with taste receptors.

Cahn-Ingold-Prelog Priority Rules

The Cahn-Ingold-Prelog (CIP) priority rules are a set of guidelines used to assign priorities to substituents attached to chiral centers based on atomic number and connectivity. These rules help determine the R or S configuration of each asymmetric center. Applying these rules is essential for accurately describing the stereochemistry of aspartame and understanding its molecular behavior.

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