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

6. Thermodynamics and Kinetics

Carbocation Intermediate Rearrangements

Organic Chemistry

6. Thermodynamics and Kinetics

Carbocation Intermediate Rearrangements

Previous problemNext problem

Problem 45b

Textbook Question

Which of the following carbocations would you expect to rearrange? If you expect rearrangement, draw the carbocation you expect to form and the mechanism by which it will form.
(b)

Verified step by step guidance

Analyze the given carbocation structure: The carbocation is located on a secondary carbon atom, which is less stable than a tertiary carbocation.

Consider the possibility of carbocation rearrangement: Carbocations tend to rearrange to form a more stable structure, typically moving from secondary to tertiary carbons.

Identify the potential rearrangement mechanism: A hydride shift (movement of a hydrogen atom with its bonding electrons) or an alkyl shift can occur to stabilize the carbocation.

Determine the new carbocation structure: If a hydride shift occurs, the positive charge will move to the tertiary carbon, resulting in a more stable tertiary carbocation.

Draw the mechanism: Illustrate the movement of the hydride or alkyl group and the resulting carbocation structure, ensuring the new carbocation is more stable than the original.

Verified video answer for a similar problem:

This video solution was recommended by our tutors as helpful for the problem above

Play a video:

Was this helpful?

Key Concepts

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

Carbocation Stability

Carbocations are positively charged carbon species that can be classified based on their stability: primary, secondary, and tertiary. Tertiary carbocations are the most stable due to hyperconjugation and inductive effects from surrounding alkyl groups. Understanding the stability of carbocations is crucial for predicting their behavior, including whether they will rearrange to form more stable structures.

Carbocation Rearrangement

Carbocation rearrangement occurs when a carbocation shifts to a more stable form, often through hydride or alkyl shifts. This process is driven by the stability of the resulting carbocation, which can lead to the formation of a more stable tertiary carbocation from a less stable primary or secondary one. Recognizing potential rearrangements is essential for predicting reaction pathways in organic chemistry.

Mechanism of Rearrangement

The mechanism of carbocation rearrangement typically involves the migration of a hydrogen atom or an alkyl group to the positively charged carbon. This process can be illustrated through curved arrows in reaction mechanisms, showing the movement of electrons. Understanding these mechanisms helps in visualizing how carbocations evolve during reactions and aids in predicting the products formed.

Watch next

Master Understanding why carbocations shift. with a bite sized video explanation from Johnny

Start learning

Related Videos

Related Practice

Textbook Question

Show a reaction coordinate diagram for the two processes in Figure 13.41 that rationalizes pathway B as the one that gives the major product.

<IMAGE>

Textbook Question

In a strongly acidic solution, cyclohexa-1,4-diene tautomerizes to cyclohexa-1,3-diene. Propose a mechanism for this rearrangement, and explain why it is energetically favorable.

Textbook Question

The molecular orbital picture of H₂ can be represented by the following diagram. Label σ and σ* on the diagram—that is, which is (a) and which is (b)? Which is lower in energy? Why?

<IMAGE>

Textbook Question

Which of the following carbocations would you expect to rearrange? If you expect rearrangement, draw the carbocation you expect to form and the mechanism by which it will form.

(a)

Textbook Question

Which of the following carbocations would you expect to rearrange? If you expect rearrangement, draw the carbocation you expect to form and the mechanism by which it will form.

(e)

Textbook Question

Which of the following carbocations would you expect to rearrange? If you expect rearrangement, draw the carbocation you expect to form and the mechanism by which it will form.

(e)

Textbook Question

Our wayward chemist from Assessment 8.23 suggested the following stepwise mechanism for a hydride shift. Show this mechanism on a reaction coordinate diagram to illustrate why the concerted mechanism is more likely. Justify the picture you have drawn.

Open Question

Which of the following carbocations would be likely to rearrange? Draw each rearranged structure below.

Molecule I

Show more practices