Textbook Question
Reduction of an alkyne using the Lindlar catalyst, a reaction presented in Section 10.6.2, produces only the cis-alkene. Why?
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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 13c
In each Diels–Alder reaction shown, predict the product that will result.
(c) 
Verified step by step guidance1
Identify the diene and the dienophile in the given Diels–Alder reaction. The diene is typically a conjugated system with four π electrons, and the dienophile is an alkene or alkyne that will react with the diene.
Examine the stereochemistry of the diene and dienophile. The Diels–Alder reaction is stereospecific, meaning that the stereochemistry of the reactants will influence the stereochemistry of the product.
Consider the electron-withdrawing groups on the dienophile. These groups can enhance the reactivity of the dienophile by making it more electrophilic, which facilitates the cycloaddition reaction.
Predict the regiochemistry of the product. The orientation of substituents in the diene and dienophile will determine the regiochemistry of the cycloaddition, often following the 'endo rule' where the major product has substituents oriented towards the larger bridge in the transition state.
Draw the resulting cyclohexene product, ensuring that you account for the stereochemistry and regiochemistry determined in the previous steps. The product will be a six-membered ring formed by the cycloaddition of the diene and dienophile.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Diels–Alder Reaction
The Diels–Alder reaction is a [4+2] cycloaddition between a conjugated diene and a dienophile, typically forming a six-membered ring. It is a pericyclic reaction that proceeds via a concerted mechanism, meaning bonds are formed simultaneously without intermediates. Understanding the stereochemistry and regiochemistry of the reactants is crucial for predicting the product.
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Diels-Alder Retrosynthesis
Conjugated Diene
A conjugated diene consists of two double bonds separated by a single bond, allowing for electron delocalization across the π-system. This electron-rich structure is essential for the Diels–Alder reaction, as it interacts with the electron-deficient dienophile. The s-cis conformation of the diene is necessary for effective overlap of orbitals during the reaction.
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Dienophile
A dienophile is typically an electron-deficient alkene or alkyne that reacts with a diene in the Diels–Alder reaction. The presence of electron-withdrawing groups on the dienophile enhances its reactivity by making it more electrophilic. The orientation and substituents on the dienophile influence the stereochemistry and regiochemistry of the resulting cyclohexene product.
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09:48General Features
Related Practice
Textbook Question
Predict the product of the following Diels–Alder reactions. Where a racemic mixture is produced, show both enantiomers and explain how each is formed.
(d)
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Textbook Question
Diene A participates in a fast and efficient Diels–Alder reaction with maleic anhydride, the powerful dienophile from Assessment 22.9. However, the related diene B does not undergo a Diels–Alder reaction. Why?
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Textbook Question
Assuming the diene approaches the dienophile from the top, predict the product of the following Diels–Alder reactions.
(c)
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Textbook Question
Figure 22.16(a) <IMAGE> shows a unique example where the Diels–Alder reaction gives a single product (no enantiomers) regardless of whether the diene attacks the dienophile from the top or bottom.
(a) Show the product of the diene attacking from the bottom and confirm that the same product is obtained.
(b) What is special about this product that makes this true?
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Textbook Question
In each Diels–Alder reaction shown, predict the product that will result.
(a)
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