Domanda del libro di testo
Show that the [4 + 2] Diels–Alder reaction is photochemically forbidden.
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Ch. 15 - Conjugated Systems, Orbital Symmetry, and Ultraviolet Spectroscopy
Wade9th EditionOrganic ChemistryISBN: 9780135213728
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TOC.tableOfContents
- Ch.1 - Structure and Bonding107
- Ch. 2 - Acids and Bases; Functional Groups115
- Ch.3 - Structure and Stereochemistry of Alkanes100
- Ch.4 - The Study of Chemical Reactions99
- Ch.5 - Stereochemistry93
- Ch.6 - Alkyl Halides; Nucleophilic Substitution118
- Ch. 7 - Structure and Synthesis of Alkenes; Elimination158
- Ch.8 - Reactions of Alkenes171
- Ch.9 - Alkynes91
- Ch.10 - Structure and Synthesis of Alcohols143
- Ch.11 - Reactions of Alcohols104
- Ch. 12 - Infrared Spectroscopy and Mass Spectrometry22
- Ch. 13 - Nuclear Magnetic Resonance Spectroscopy45
- Ch. 14 - Ethers, Epoxides, and Thioethers72
- Ch. 15 - Conjugated Systems, Orbital Symmetry, and Ultraviolet Spectroscopy89
- Ch. 16 - Aromatic Compounds74
- Ch. 17 - Reactions of Aromatic Compounds126
- Ch. 18 - Ketones and Aldehydes193
- Ch. 19 - Amines129
- Ch. 20 - Carboxylic Acids77
- Ch. 21 - Carboxylic Acid Derivatives141
- Ch. 22 - Condensations and Alpha Substitutions of Carbonyl Compounds175
- Ch. 23 - Carbohydrates and Nucleic Acids93
- Ch. 24 - Amino Acids, Peptides, and Proteins54
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Wade 9th EditionCh. 15 - Conjugated Systems, Orbital Symmetry, and Ultraviolet SpectroscopyProblema 18c,d
Wade 9th EditionCh. 15 - Conjugated Systems, Orbital Symmetry, and Ultraviolet SpectroscopyProblema 18c,dCapitolo 15, Problema 18c,d
Predict the products of the following Diels–Alder reactions.
(c) 
(d) 
Guida verificata passo dopo passo1
Step 1: Identify the diene and dienophile in each reaction. In the first image, the diene is the compound with the CH3O group and two conjugated double bonds, while the dienophile is the compound with the CHO group and a single double bond. In the second image, the diene is the compound with two conjugated double bonds and CH3 groups, while the dienophile is the compound with the CN group and a single double bond.
Step 2: Recall the Diels–Alder reaction mechanism. It is a [4+2] cycloaddition reaction where the diene contributes four π-electrons and the dienophile contributes two π-electrons to form a six-membered ring.
Step 3: Analyze the electron-withdrawing groups (EWGs) on the dienophile. In the first reaction, the CHO group is an EWG, which enhances the reactivity of the dienophile. In the second reaction, the CN group is an EWG, which also enhances the reactivity of the dienophile.
Step 4: Predict the regiochemistry of the reaction. The electron-donating group (CH3O) on the diene will direct the reaction to form the most stable product. Similarly, the CH3 groups on the diene in the second reaction will influence the regioselectivity of the product.
Step 5: Draw the product structure. Combine the diene and dienophile to form a six-membered ring. Ensure that the substituents (CH3O, CHO, CH3, CN) are correctly positioned based on the regioselectivity and stereochemistry of the reaction.
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Diels–Alder Reaction
The Diels–Alder reaction is a [4+2] cycloaddition reaction between a conjugated diene and a dienophile, resulting in the formation of a six-membered ring. This reaction is a key method in organic synthesis for constructing cyclic compounds and is characterized by its stereospecificity and regioselectivity, making it a powerful tool for chemists.
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Diels-Alder Retrosynthesis
Conjugated Dienes
Conjugated dienes are compounds that contain two double bonds separated by a single bond, allowing for resonance stabilization. This structure enhances their reactivity in Diels–Alder reactions, as the electron-rich diene can effectively interact with the electron-deficient dienophile, facilitating the formation of new bonds during the reaction.
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03:27Conjugated states
Dienophile
A dienophile is a compound that contains a double or triple bond and reacts with a diene in a Diels–Alder reaction. Typically, dienophiles are electron-deficient, which makes them more reactive towards the electron-rich diene. Common examples include alkenes and alkynes with electron-withdrawing groups, which enhance their reactivity in cycloaddition reactions.
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09:48General Features
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