Textbook Question
Show how Friedel–Crafts acylation might be used to synthesize the following compounds.
c. n-butylbenzene
3
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Ch. 21 - Carboxylic Acid Derivatives
Wade9th EditionOrganic ChemistryISBN: 9780135213728
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Table of contents
- 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
Chapter 21, Problem 30a
Show how Friedel–Crafts acylation might be used to synthesize the following compounds.
a. acetophenone
Verified step by step guidance1
Step 1: Understand the Friedel–Crafts acylation reaction. This reaction involves the introduction of an acyl group (RCO-) into an aromatic ring using an acyl chloride (RCOCl) and a Lewis acid catalyst, typically aluminum chloride (AlCl₃). The aromatic ring acts as the nucleophile, and the acyl group is the electrophile.
Step 2: Identify the target compound, acetophenone. Acetophenone is a ketone with a phenyl group (C₆H₅) attached to a methyl group via a carbonyl group (C=O). The structure can be represented as C₆H₅COCH₃.
Step 3: Choose the appropriate acylating agent. To synthesize acetophenone, the acyl group needed is CH₃CO-. The acylating agent for this reaction would be acetyl chloride (CH₃COCl).
Step 4: Set up the reaction. Combine benzene (C₆H₆) with acetyl chloride (CH₃COCl) in the presence of a Lewis acid catalyst, such as aluminum chloride (AlCl₃). The catalyst facilitates the generation of the acylium ion (CH₃CO⁺), which is the active electrophile in the reaction.
Step 5: Mechanism overview. The acylium ion (CH₃CO⁺) reacts with the benzene ring via electrophilic aromatic substitution. The benzene ring donates electrons to the acylium ion, forming a carbocation intermediate. This intermediate is stabilized by resonance, and the catalyst helps regenerate aromaticity by removing a proton from the ring. The final product is acetophenone (C₆H₅COCH₃).
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Friedel–Crafts Acylation
Friedel–Crafts acylation is an electrophilic aromatic substitution reaction that introduces an acyl group into an aromatic ring. This reaction typically involves the use of an acyl chloride and a Lewis acid catalyst, such as aluminum chloride, to generate the acylium ion, which then reacts with the aromatic compound. The result is a ketone, making this method particularly useful for synthesizing aromatic ketones.
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Friedel-Crafts Acylation
Aromatic Compounds
Aromatic compounds are cyclic, planar molecules that follow Huckel's rule, possessing a certain number of π electrons (4n + 2, where n is a non-negative integer). These compounds exhibit unique stability due to resonance, which allows for delocalization of electrons. Understanding the structure and reactivity of aromatic compounds is crucial for predicting the outcomes of reactions like Friedel–Crafts acylation.
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Acetophenone Structure
Acetophenone is an aromatic ketone with the chemical formula C8H8O, consisting of a phenyl group (C6H5) attached to an acetyl group (C2H3O). Its structure is essential for understanding how Friedel–Crafts acylation can be employed to synthesize it. The reaction involves the introduction of the acetyl group onto the aromatic ring, resulting in the formation of acetophenone as the final product.
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Related Practice
Textbook Question
Show how you would add a Grignard reagent to an ester or a nitrile to synthesize
(c) pentan-2-one.
1
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Textbook Question
Show how you would add a Grignard reagent to an ester or a nitrile to synthesize
(b) heptan-4-ol.
3
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Textbook Question
Show how you would use anhydrides to synthesize the following compounds. In each case, explain why an anhydride might be preferable to an acid chloride.
(a) n-octyl formate
(b) n-octyl acetate
1
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Textbook Question
Show how Friedel–Crafts acylation might be used to synthesize the following compounds.
b. benzophenone
8
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Textbook Question
Show how you would add a Grignard reagent to an ester or a nitrile to synthesize
(a) 4-phenylheptan-4-ol.
1
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