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

7. Substitution Reactions

Substitution Comparison

Organic Chemistry

7. Substitution Reactions

Substitution Comparison

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Problem 54b

Textbook Question

Predict the product of the following substitution reactions, paying close attention to the stereochemical outcome of the reactions.
(b)

Verified step by step guidance

Analyze the reaction conditions: The presence of CH3SNa (sodium methanethiolate) and DMSO (dimethyl sulfoxide) suggests that this is an SN2 reaction. SN2 reactions are bimolecular nucleophilic substitutions that proceed with inversion of stereochemistry at the carbon center undergoing substitution.

Identify the substrate: The substrate is a bromocyclopentane derivative with a bromine atom attached to a stereogenic center. Bromine is a good leaving group, making this substrate suitable for an SN2 reaction.

Determine the nucleophile: CH3SNa provides the nucleophile CH3S⁻ (methanethiolate ion), which is a strong nucleophile due to its negative charge and sulfur atom's nucleophilicity.

Predict the stereochemical outcome: In an SN2 reaction, the nucleophile attacks the electrophilic carbon from the side opposite to the leaving group (backside attack). This results in inversion of configuration at the stereogenic center.

Write the product structure: Replace the bromine atom with the CH3S group, ensuring that the stereochemistry is inverted relative to the original configuration of the bromine atom. The product will be a cyclopentane derivative with the CH3S group attached in the opposite stereochemical orientation.

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Key Concepts

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

Nucleophilic Substitution Reactions

Nucleophilic substitution reactions involve the replacement of a leaving group in a molecule by a nucleophile. These reactions can occur via two main mechanisms: SN1 and SN2. The SN1 mechanism is a two-step process that involves the formation of a carbocation intermediate, while the SN2 mechanism is a one-step process where the nucleophile attacks the substrate simultaneously as the leaving group departs.

Stereochemistry

Stereochemistry refers to the study of the spatial arrangement of atoms in molecules and how this affects their chemical behavior. In substitution reactions, the stereochemical outcome is crucial, especially in SN2 reactions, where the nucleophile attacks from the opposite side of the leaving group, leading to inversion of configuration. Understanding stereochemistry helps predict the 3D orientation of the product.

Leaving Groups

Leaving groups are atoms or groups that can depart from the parent molecule during a chemical reaction, facilitating nucleophilic substitution. A good leaving group is typically stable after departure, such as halides or sulfonate groups. The nature of the leaving group significantly influences the reaction rate and mechanism, making it essential to identify them when predicting reaction products.

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