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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Multiple Choice

What is the absolute configuration of the following stereocenters?

I: S, II: R

I: R, II: S

I: S, II: S

I: R, II: R

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Verified step by step guidance

Identify the stereocenters in the molecule. In the image, stereocenter I is the carbon bonded to Br, and stereocenter II is the carbon bonded to the ethyl group (CH2CH3).

Assign priorities to the substituents around each stereocenter based on atomic number. For stereocenter I, the substituents are Br, CH3, CH2CH3, and the hydrogen (not shown, but implied). For stereocenter II, the substituents are CH2CH3, CH3, the rest of the carbon chain, and the hydrogen (not shown, but implied).

For stereocenter I, assign priority: Br (highest atomic number) > CH2CH3 > CH3 > H. For stereocenter II, assign priority: CH2CH3 > CH3 > the rest of the carbon chain > H.

Determine the configuration by arranging the substituents in order of priority and observing the direction of rotation. For stereocenter I, if the lowest priority group (H) is pointing away, observe the sequence from highest to lowest priority. If the sequence is clockwise, the configuration is R; if counterclockwise, it is S. Repeat the process for stereocenter II.

Verify the configurations by considering the orientation of the lowest priority group. If the lowest priority group is not pointing away, reverse the observed configuration. Compare your findings with the given options to determine the correct absolute configuration for each stereocenter.