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

8. Elimination Reactions

SN1 SN2 E1 E2 Chart (Big Daddy Flowchart)

Organic Chemistry

8. Elimination Reactions

SN1 SN2 E1 E2 Chart (Big Daddy Flowchart)

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4:28 minutes

Problem 38a

Textbook Question

Draw the substitution and elimination products for the following reactions, showing the configuration of each product:
a. trans-1-chloro-2-methylcyclohexane + CH₃O⁻

Verified step by step guidance

Analyze the structure of the starting material, trans-1-chloro-2-methylcyclohexane. The chlorine atom is on one carbon of the cyclohexane ring, and the methyl group is on the adjacent carbon. Since the molecule is trans, the chlorine and methyl groups are on opposite sides of the ring (one axial and one equatorial).

Determine the type of reaction mechanism that can occur with CH3O⁻ (methoxide ion). CH3O⁻ is a strong base and a strong nucleophile, so both substitution (S_N2) and elimination (E2) reactions are possible. The reaction pathway depends on steric and electronic factors.

For the substitution (S_N2) pathway: The methoxide ion will attack the carbon bonded to the chlorine atom (the leaving group). Since S_N2 reactions proceed via a backside attack, the stereochemistry of the product will invert at the carbon where substitution occurs. Draw the product with the methoxy group replacing the chlorine, ensuring the stereochemistry is inverted.

For the elimination (E2) pathway: The methoxide ion will abstract a β-hydrogen (a hydrogen on a carbon adjacent to the carbon bearing the chlorine). In this case, the β-hydrogen must be anti-periplanar to the chlorine atom for the elimination to occur. Identify the anti-periplanar β-hydrogen, and draw the resulting alkene product. Ensure the double bond is formed between the carbon bearing the chlorine and the β-carbon, and show the correct stereochemistry of the alkene.

Summarize the products: For substitution, the product is the inverted stereochemical product with the methoxy group. For elimination, the product is the alkene with the correct stereochemistry based on the anti-periplanar geometry. Ensure both products are clearly drawn with their configurations labeled.

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Key Concepts

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

Substitution Reactions

Substitution reactions involve the replacement of one atom or group in a molecule with another atom or group. In organic chemistry, nucleophilic substitution is common, where a nucleophile attacks an electrophilic carbon, leading to the formation of a new bond while the leaving group departs. Understanding the mechanism (SN1 or SN2) is crucial, as it influences the stereochemistry and regioselectivity of the products.

Elimination Reactions

Elimination reactions involve the removal of a small molecule (often water or a halide) from a larger molecule, resulting in the formation of a double bond. In organic chemistry, common types include E1 and E2 mechanisms. The choice between substitution and elimination often depends on the structure of the substrate and the conditions of the reaction, such as the strength of the base used.

Stereochemistry

Stereochemistry refers to the spatial arrangement of atoms in molecules and how this affects their chemical behavior. In reactions involving chiral centers, the configuration (R/S) of products is critical, as it can influence the reactivity and properties of the compounds formed. Understanding stereochemistry is essential for predicting the outcomes of substitution and elimination reactions, especially in cyclic compounds like cyclohexane.

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