교과서 질문
One of the following compounds undergoes electrophilic aromatic substitution predominantly at C-3, and one undergoes electrophilic aromatic substitution predominantly at C-4. Which is which?
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Ch. 19 - More About Amines • Reactions of Heterocyclic Compounds
Bruice8th EditionOrganic ChemistryISBN: 9780135213711
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TOC.tableOfContents
- Ch. 1 - Remembering General Chemistry: Electronic Structure and Bonding31
- Ch. 2 - Acids and Bases: Central to Understanding Organic Chemistry84
- Ch. 3 - An Introduction to Organic Compounds: Nomenclature, Physical Properties, and Structure183
- Ch. 4 - Isomers: The Arrangement of Atoms in Space121
- Ch. 5 - Alkenes: Structure, Nomenclature, and an Introduction to Reactivity • Thermodynamics and Kinetics83
- Ch. 6 - The Reactions of Alkenes • The Stereochemistry of Addition Reactions175
- Ch. 7 - The Reactions of Alkynes • An Introduction to Multistep Synthesis119
- Ch. 8 - Delocalized Electrons: Their Effect on Stability, pKa, and the Products of a Reaction • Aromaticity and Electronic Effects: An Introduction to the Reactions of Benzene148
- Ch. 9 - Substitution and Elimination Reactions of Alkyl Halides212
- Ch. 10 - Reactions of Alcohols, Ethers, Epoxides, Amines, and Sulfur-Containing Compounds131
- Ch. 11 - Organometallic Compounds60
- Ch. 12 - Radicals90
- Ch. 13 - Mass Spectrometry; Infrared Spectroscopy; UV/Vis Spectroscopy62
- Ch. 14 - NMR Spectroscopy95
- Ch. 15 - Reactions of Carboxylic Acids and Carboxylic Acid Derivatives123
- Ch. 16 - Reactions of Aldehydes and Ketones • More Reactions of Carboxylic Acid Derivatives141
- Ch. 17 - Reactions at the Alpha-Carbon101
- Ch. 18 - Reactions of Benzene and Substituted Benzenes144
- Ch. 19 - More About Amines • Reactions of Heterocyclic Compounds49
- Ch. 20 - The Organic Chemistry of Carbohydrates80
- Ch. 21 - Amino Acids, Peptides, and Proteins57
- Ch. 22 - Catalysis in Organic Reactions and in Enzymatic Reactions35
- Ch. 23 - The Organic Chemistry of the Coenzymes—Compounds Derived from Vitamins1
- Ch. 28 - Pericyclic Reactions58
19장, 문제 27
Benzene undergoes electrophilic aromatic substitution reactions with aziridines in the presence of a Lewis acid such as AlCl3.
a. What are the major and minor products of the following reaction?
b. Would you expect epoxides to undergo similar reactions?
검증된 단계별 안내1
Step 1: Understand the reaction mechanism. Benzene undergoes electrophilic aromatic substitution (EAS) reactions, where an electrophile replaces one of the hydrogen atoms on the aromatic ring. In this case, aziridines act as electrophiles in the presence of a Lewis acid like AlCl₃, which activates the aziridine by coordinating with the nitrogen atom, making the aziridine more electrophilic.
Step 2: Predict the major product. The aziridine ring opens during the reaction, and the benzene ring attacks the more electrophilic carbon of the aziridine. This results in the formation of a new bond between the benzene ring and the aziridine-derived carbon. The major product will be determined by the regioselectivity of the ring-opening process, which typically favors the more stable carbocation intermediate.
Step 3: Predict the minor product. The minor product arises from the less favorable regioselective pathway of the aziridine ring opening. This pathway involves the formation of a less stable carbocation intermediate, leading to a less favored substitution product.
Step 4: Address part (b) of the question. Epoxides are three-membered cyclic ethers, and they can also undergo ring-opening reactions. However, their reactivity in electrophilic aromatic substitution reactions is different from aziridines. Epoxides are less electrophilic than aziridines because oxygen is less effective at stabilizing a positive charge compared to nitrogen. Therefore, epoxides are less likely to undergo similar EAS reactions under the same conditions.
Step 5: Summarize the key points. The major product of the reaction involves the regioselective opening of the aziridine ring, leading to the most stable carbocation intermediate. The minor product arises from the less favorable pathway. Epoxides are less reactive in this context due to their lower electrophilicity compared to aziridines.
비슷한 문제에 대한 검증된 영상 답변:
이 영상 해법은 위 문제에 도움이 된다고 튜터들이 추천한 것입니다.
주요 개념
질문에 올바르게 답하기 위해 반드시 이해해야 하는 핵심 개념들은 다음과 같습니다.
Electrophilic Aromatic Substitution (EAS)
Electrophilic Aromatic Substitution is a fundamental reaction in organic chemistry where an electrophile replaces a hydrogen atom on an aromatic ring. This process typically involves the formation of a sigma complex, where the aromaticity is temporarily lost, followed by deprotonation to restore the aromatic character. Understanding EAS is crucial for predicting the products of reactions involving aromatic compounds like benzene.
추천 영상:
03:07
EAS Review
Lewis Acids and Bases
Lewis acids are electron pair acceptors, while Lewis bases are electron pair donors. In the context of the reaction with benzene and aziridines, a Lewis acid like AlCl3 activates the electrophile, enhancing its reactivity towards the aromatic ring. This concept is essential for understanding how the presence of a Lewis acid can facilitate electrophilic aromatic substitution reactions.
추천 영상:
02:49The Lewis definition of acids and bases.
Reactivity of Epoxides
Epoxides are three-membered cyclic ethers that are highly reactive due to the strain in their ring structure. They can undergo nucleophilic attack and other reactions, but their behavior in electrophilic aromatic substitution differs from that of aziridines. Understanding the unique properties of epoxides helps in predicting their reactivity and potential products in similar reactions with aromatic compounds.
추천 영상:
02:19General properties of epoxidation.
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