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

9. Alkenes and Alkynes

Zaitsev Rule

Organic Chemistry

9. Alkenes and Alkynes

Zaitsev Rule

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1:20 minutes

Problem 35b

Textbook Question

What is the major product formed when the following compounds undergo an E1 reaction?
b.

Verified step by step guidance

Step 1: Understand the E1 reaction mechanism. E1 reactions are unimolecular elimination reactions where the rate-determining step involves the formation of a carbocation intermediate. This typically occurs in the presence of a weak base and a polar protic solvent.

Step 2: Identify the leaving group in the given compound. The leaving group must be able to depart easily, forming a stable carbocation intermediate. Common leaving groups include halides (e.g., Cl⁻, Br⁻, I⁻) or sulfonates (e.g., OTs).

Step 3: Analyze the stability of the carbocation intermediate formed after the leaving group departs. Carbocation stability follows the order: tertiary > secondary > primary > methyl. If resonance stabilization is possible, it further enhances carbocation stability.

Step 4: Determine the major product by considering the most substituted alkene formed via the elimination of a proton from a β-hydrogen. This follows Zaitsev's rule, which states that the more substituted alkene is generally the major product.

Step 5: Consider any rearrangements that might occur. If the initially formed carbocation can rearrange to a more stable carbocation (e.g., via hydride or alkyl shifts), this rearrangement will influence the final product.

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Key Concepts

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

E1 Reaction Mechanism

The E1 reaction mechanism is a type of elimination reaction that occurs in two distinct steps. The first step involves the formation of a carbocation intermediate through the loss of a leaving group, while the second step involves the deprotonation of a neighboring carbon to form a double bond. This mechanism is favored in polar protic solvents and typically occurs with tertiary or some secondary substrates due to their ability to stabilize the carbocation.

Carbocation Stability

Carbocation stability is a crucial factor in determining the outcome of E1 reactions. Carbocations are positively charged species that can vary in stability based on their structure; tertiary carbocations are more stable than secondary, which are more stable than primary. The stability is influenced by factors such as hyperconjugation and inductive effects from adjacent alkyl groups, which can help to stabilize the positive charge.

Regioselectivity in Elimination Reactions

Regioselectivity refers to the preference of a chemical reaction to yield one structural isomer over others when multiple products are possible. In E1 reactions, the major product often results from the most stable alkene, which is determined by the Zaitsev's rule, stating that the more substituted alkene is favored. Understanding regioselectivity is essential for predicting the major product formed in elimination reactions.

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Textbook Question

Draw the major product obtained when an alkyl halide in [PROBLEM 9-83] undergoes an E1 reaction.

Textbook Question

Predict the products of E1 elimination of the following compounds. Label the major products.

(c)

Textbook Question

What is the major product formed when the following compounds undergo an E1 reaction?

Textbook Question

Predict the major product(s) of the following elimination reactions, paying close attention to the stereochemical outcome of the reactions.

(c)

Textbook Question

Predict the major product(s) of the following elimination reactions, paying close attention to the stereochemical outcome of the reactions.

(e)

Textbook Question

For each of the following compounds, draw the product that forms in an E2 reaction and indicate its configuration:

a. (1S,2S)-1-bromo-1,2-diphenylpropane

Textbook Question

When (1-bromoethyl)cyclohexane is heated in methanol for an extended period of time, five products result: two ethers and three alkenes. Predict which of the three alkenes is the major elimination product.

Textbook Question

Predict the products of E1 elimination of the following compounds. Label the major products.

(a)

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