Textbook Question
Predict the product of the Claisen reactions shown.
(b)
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Ch. 22 - Conjugated Systems II: Pericyclic Reactions
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
Chapter 21, Problem 40a
Predict the product of the Cope reactions shown.
(a) 
Verified step by step guidance1
Identify the structure of the starting material: The Cope rearrangement involves a 1,5-diene system. Look for a six-membered transition state that can form from the starting material.
Draw the transition state: Visualize the six-membered cyclic transition state that forms during the Cope rearrangement. This involves a concerted movement of electrons, where the π-bonds and σ-bonds are reorganized.
Determine the new bond formation: In the transition state, identify which bonds are breaking and which new bonds are forming. This will help you predict the structure of the product.
Consider stereochemistry: If the starting material has stereocenters, consider how the rearrangement might affect the stereochemistry of the product. The Cope rearrangement is a pericyclic reaction, which often preserves stereochemistry.
Draw the product: Based on the rearrangement and the new bond formations, draw the structure of the product. Ensure that the connectivity and any relevant stereochemistry are accurately represented.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Cope Rearrangement
The Cope rearrangement is a [3,3]-sigmatropic reaction involving the rearrangement of 1,5-dienes. It is a pericyclic reaction where the sigma bonds are broken and formed simultaneously, resulting in a new 1,5-diene. This reaction is thermally induced and proceeds through a cyclic transition state, often leading to the formation of more stable isomers.
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Definition of Cope Rearrangement
Sigmatropic Rearrangements
Sigmatropic rearrangements are a class of pericyclic reactions where a sigma bond adjacent to one or more pi systems migrates across the pi system. These reactions are characterized by the conservation of orbital symmetry and often involve cyclic transition states. The Cope rearrangement is a specific example of a [3,3]-sigmatropic shift, where the numbers indicate the positions of the atoms involved in the bond migration.
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Thermal Activation
Thermal activation refers to the use of heat to provide the energy necessary for a chemical reaction to occur. In the context of the Cope rearrangement, heat is used to overcome the activation energy barrier, allowing the reaction to proceed through its cyclic transition state. The reaction's feasibility and rate can be influenced by the temperature, as well as the stability of the transition state and the final product.
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Related Practice
Textbook Question
Draw the products you’d expect to form in Assessment 22.38.
(c)
537
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Textbook Question
Given the conditions, would you expect conrotatory or disrotatory ring closing/opening? Justify this on the basis of the molecular orbital picture.
(c)
632
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Textbook Question
Predict the product of the Claisen reactions shown.
(c)
1236
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Textbook Question
For the following electrocyclic reactions, did the substituents move in a conrotatory or disrotatory direction? Would you use heat or light to cause movement in this direction?
(a)
1210
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Textbook Question
Predict the product of the Cope reactions shown.
(c)
1282
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