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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5:09 minutes

Problem 51e

Textbook Question

Assign the absolute stereochemistry for each of the following molecules.
(e)

Verified step by step guidance

Step 1: Identify the stereocenter in the molecule. The stereocenter is the carbon atom bonded to four different groups: the amino group (NH₂), the carboxylic acid group (CO₂H), the hydrogen atom (H), and the phenyl group (C₆H₅).

Step 2: Assign priorities to the substituents attached to the stereocenter based on the Cahn-Ingold-Prelog (CIP) priority rules. The priority is determined by atomic number: (1) CO₂H (highest priority due to oxygen), (2) NH₂, (3) C₆H₅, and (4) H (lowest priority).

Step 3: Orient the molecule so that the lowest priority group (H) is pointing away from you. This is typically represented as a dashed wedge in the diagram.

Step 4: Determine the order of the remaining three groups (CO₂H, NH₂, and C₆H₅) as you move clockwise or counterclockwise. Trace the path from the highest priority group (CO₂H) to the second (NH₂) and then to the third (C₆H₅).

Step 5: Assign the absolute configuration based on the direction of the path. If the path is clockwise, the configuration is R. If the path is counterclockwise, the configuration is S.

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Key Concepts

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

Stereochemistry

Stereochemistry is the study of the spatial arrangement of atoms in molecules and how this affects their chemical behavior. It is crucial for understanding isomers, particularly enantiomers, which are non-superimposable mirror images of each other. In organic chemistry, stereochemistry is often denoted using the R/S system, which helps in assigning absolute configurations to chiral centers.

Chirality

Chirality refers to the property of a molecule that makes it non-superimposable on its mirror image, much like left and right hands. A chiral molecule typically has one or more chiral centers, usually carbon atoms bonded to four different substituents. Identifying chirality is essential for assigning stereochemistry, as it determines the molecule's optical activity and interactions in biological systems.

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 a chiral center based on atomic number and connectivity. The highest priority is given to the atom with the highest atomic number directly attached to the chiral center. These rules are fundamental for determining the R or S configuration of chiral molecules, which is necessary for accurately describing their stereochemistry.

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Related Practice

Textbook Question

Complete the structure of each of these so that it matches the (R) or (S) configuration associated with the name.

(d)

Textbook Question

Complete the structure of each of these so that it matches the (R) or (S) configuration associated with the name.

(e)

Textbook Question

Name the following alkynes according to the IUPAC rules of nomenclature.

(d)

Textbook Question

In Chapter 12, we introduce the S_N2 reaction, a nucleophilic substitution reaction that proceeds with inversion. Confirm that inversion has occurred in each of the following examples by determining the absolute configuration of the chiral center in the reactants and products.

(a)

Textbook Question

Assign the absolute stereochemistry for each of the following molecules.

(f)

Textbook Question

Prioritize the substituents at each chiral center and then, by comparing them to the models you created in Section 6.3.2, label the absolute configuration as R or S.

(d)

Textbook Question

Prioritize the substituents at each chiral center and then, by comparing them to the models you created in Section 6.3.2, label the absolute configuration as R or S

(f)

Textbook Question

What is the configuration of each of the asymmetric centers in the following compounds?

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