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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3:48 minutes

Problem 115b

Textbook Question

Draw the products of each of the following S_N2/E2 reactions. If the products can exist as stereoisomers, show which stereoisomers are formed.
b. (3R,4R)-3-bromo-4-methylhexane + CH₃O⁻

Verified step by step guidance

Identify the type of reaction: The problem specifies SN2/E2 reactions. SN2 reactions involve a backside attack by the nucleophile, leading to inversion of configuration at the carbon center. E2 reactions involve elimination, forming a double bond between adjacent carbons.

Analyze the substrate: The substrate is (3R,4R)-3-bromo-4-methylhexane. The bromine atom is attached to the 3rd carbon, and the 4th carbon has a methyl group. The stereochemistry is specified as (3R,4R), so the 3rd carbon is in the R configuration, and the 4th carbon is also in the R configuration.

Consider the nucleophile/base: CH3O⁻ (methoxide ion) is both a strong nucleophile and a strong base. This means it can participate in both SN2 and E2 mechanisms. The reaction conditions will determine which pathway dominates.

Determine the products for each mechanism: For the SN2 reaction, the methoxide ion will attack the 3rd carbon (where the bromine is attached) from the opposite side, displacing the bromine and inverting the configuration at the 3rd carbon. For the E2 reaction, the methoxide ion will abstract a β-hydrogen (from the 2nd or 4th carbon), leading to the formation of a double bond between the 2nd and 3rd carbons or the 3rd and 4th carbons. Consider Zaitsev's rule, which favors the more substituted alkene.

Account for stereoisomers: For the SN2 product, the inversion of configuration at the 3rd carbon will result in a specific stereoisomer. For the E2 product, if a double bond forms between the 3rd and 4th carbons, cis/trans (E/Z) isomerism may occur. Draw all possible stereoisomers for the products and label them clearly.

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Key Concepts

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

SN2 Reaction Mechanism

The SN2 (substitution nucleophilic bimolecular) reaction involves a nucleophile attacking an electrophile, resulting in the simultaneous displacement of a leaving group. This mechanism is characterized by a single concerted step, where the nucleophile approaches the electrophile from the opposite side of the leaving group, leading to inversion of configuration at the chiral center. Understanding this mechanism is crucial for predicting the stereochemical outcome of reactions.

E2 Reaction Mechanism

The E2 (elimination bimolecular) reaction is a one-step process where a base abstracts a proton from a β-carbon while a leaving group departs from the α-carbon, resulting in the formation of a double bond. This reaction typically requires a strong base and is stereospecific, often favoring the formation of the more stable alkene. Recognizing the conditions that favor E2 over SN2 is essential for determining the products of the reaction.

Stereoisomerism

Stereoisomerism refers to the existence of compounds with the same molecular formula and connectivity but different spatial arrangements of atoms. In the context of the given reaction, the formation of stereoisomers can occur due to the chiral centers present in the substrate. Understanding how stereochemistry is affected by the reaction mechanism (SN2 or E2) is vital for accurately depicting the products and their stereoisomers.

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Related Practice

Textbook Question

Silver-assisted solvolysis of bromomethylcyclopentane in methanol gives a complex product mixture of the following five compounds. Propose mechanisms to account for these products.

(b)

Textbook Question

Silver-assisted solvolysis of bromomethylcyclopentane in methanol gives a complex product mixture of the following five compounds. Propose mechanisms to account for these products.

(c)

Textbook Question

Silver-assisted solvolysis of bromomethylcyclopentane in methanol gives a complex product mixture of the following five compounds. Propose mechanisms to account for these products.

(d)

Textbook Question

Silver-assisted solvolysis of bromomethylcyclopentane in methanol gives a complex product mixture of the following five compounds. Propose mechanisms to account for these products.

(e)

Textbook Question

Which of the following compounds would react faster in an

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a. E1 reaction?

b. E2 reaction?

Textbook Question

What product is obtained when the following compound undergoes two successive elimination reactions?

Multiple Choice

Which of the following is NOT a reason why the given elimination reaction is favorable?

Textbook Question

After a proton is removed from the OH group, which compound in each pair forms a cyclic ether more rapidly?