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)
2
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Ch. 8 - Alkenes I: Properties and Electrophilic Additions
Mullins1st EditionOrganic Chemistry: A Learner Centered ApproachISBN: 9780137566471
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Table of contents
- Ch. 2 - General Chemistry Translated: Finding the Electrons114
- Ch. 3 - Alkanes and Cycloalkanes: Properties and Conformational Analysis109
- Ch. 4 - Acids and Bases: Electron Flow144
- Ch. 5 - Chemical Reaction Analysis: Thermodynamics and Kinetics118
- Ch. 6 - Stereoisomerism: Arrangement of Atoms in Space112
- Ch. 7 - Principles of Green (Organic) Chemistry3
- Ch. 8 - Alkenes I: Properties and Electrophilic Additions158
- Ch. 9 - Alkenes II: Oxidation and Reduction150
- Ch. 10 - Alkynes: Electrophilic Addition and Redox Reactions101
- Ch. 11 - Properties and Synthesis of Alkyl Halides: Radical Reactions108
- Ch. 12 - Substitution and Elimination: Reactions of Haloalkanes172
- Ch. 13 - Alcohols, Ethers and Related Compounds: Substitution and Elimination239
- Ch. 14 - Structural Identification I: Infrared Spectroscopy and Mass Spectrometry54
- Ch. 15 - Structural Identification II: Nuclear Magnetic Resonance Spectroscopy93
- Ch. 16 - Metals in Organic Chemistry48
- Ch. 17 - Carbonyl Addition Reactions: Aldehydes and Ketones45
- Ch. 18 - Nucleophilic Acyl Substitution I: Carboxylic Acids18
- Ch. 19 - Nucleophilic Acyl Substitution II: Carboxylic Acid Derivatives39
- Ch. 20 - Enolates: Carbonyl Addition and Substitution13
- Ch. 21 - Conjugated Systems I: Stability and Addition Reactions56
- Ch. 22 - Conjugated Systems II: Pericyclic Reactions54
- Ch. 23 - Benzene I: Aromatic Stability and Substitution Reactions64
- Ch. 24 - Benzene II: Reactions Influenced by the Aromatic Ring62
- Ch. 25 - Amines: Structure, Reactions, and Synthesis27
- Ch. 26 - Amino Acids, Proteins, and Peptide Synthesis9
- Ch. 27 - Carbohydrates, Nucleic Acids, and Lipids54
Mullins1st EditionOrganic Chemistry: A Learner Centered ApproachISBN: 9780137566471Not the one you use?Change textbook
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Mullins 1st EditionCh. 8 - Alkenes I: Properties and Electrophilic AdditionsProblem 46a
Mullins 1st EditionCh. 8 - Alkenes I: Properties and Electrophilic AdditionsProblem 46aChapter 7, Problem 46a
Provide a mechanism for the following reactions occurring with rearrangement.
(a) 
Verified step by step guidance1
Step 1: Protonation of the alkene - The reaction begins with the alkene reacting with the sulfuric acid (H₂SO₄). The π-electrons of the double bond attack the proton (H⁺) from H₂SO₄, leading to the formation of a carbocation. This step generates a secondary carbocation at the more stable position due to Markovnikov's rule.
Step 2: Carbocation rearrangement - The initially formed secondary carbocation undergoes a hydride shift (rearrangement) to form a more stable tertiary carbocation. This occurs because tertiary carbocations are more stable than secondary carbocations due to hyperconjugation and inductive effects.
Step 3: Nucleophilic attack by water - Water (H₂O) acts as a nucleophile and attacks the positively charged carbon of the tertiary carbocation, forming an oxonium ion (a positively charged oxygen species).
Step 4: Deprotonation - The oxonium ion loses a proton (H⁺) to form the final alcohol product. This step is facilitated by the surrounding water molecules acting as a base.
Step 5: Final product - The reaction yields the rearranged alcohol product, where the hydroxyl group (-OH) is attached to the carbon that was part of the tertiary carbocation.
Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Reaction Mechanisms
A reaction mechanism is a step-by-step description of how a chemical reaction occurs at the molecular level. It outlines the sequence of elementary steps, including bond breaking and forming, and the intermediates involved. Understanding mechanisms is crucial for predicting the products of reactions and the conditions under which they occur.
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Heck Reaction Mechanism
Rearrangement Reactions
Rearrangement reactions involve the structural reorganization of a molecule to form a different isomer. These reactions often occur through the migration of atoms or groups within the molecule, leading to more stable configurations. Recognizing the types of rearrangements, such as hydride shifts or alkyl shifts, is essential for predicting the outcome of the reaction.
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06:28Definition of Cope Rearrangement
Stability of Intermediates
The stability of intermediates plays a critical role in determining the pathway of a reaction. Intermediates, such as carbocations or carbanions, can significantly influence the rate and outcome of a reaction. Understanding factors that affect their stability, such as resonance and inductive effects, helps in predicting the favored reaction mechanism and products.
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04:31Stability of Conjugated Intermediates
Related Practice
Textbook Question
Provide a mechanism for the following reactions occurring with rearrangement.
(b)
1
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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.
(f)
1
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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.
2
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Textbook Question
The hydration of three C5H10 alkene isomers can give 2-methylbutan-2-ol. Draw them.
1
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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)
7
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