Textbook Question
Predict the products formed when cyclohexanone reacts with the following reagents.
(b) excess CH3OH, H+
679
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Ch. 18 - Ketones and Aldehydes
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 18, Problem 53d
Predict the products formed when cyclohexanone reacts with the following reagents.
(d) ethylene glycol and p-toluenesulfonic acid
Verified step by step guidance1
Identify the functional group in cyclohexanone: Cyclohexanone is a ketone, which contains a carbonyl group (C=O). This functional group is reactive and can undergo various transformations.
Understand the role of ethylene glycol: Ethylene glycol (HOCH2CH2OH) is a diol, meaning it has two hydroxyl (-OH) groups. In the presence of an acid catalyst, it can react with a ketone to form a cyclic acetal. This reaction is a type of protection reaction for the carbonyl group.
Understand the role of p-toluenesulfonic acid: p-Toluenesulfonic acid (TsOH) is a strong acid that acts as a catalyst in this reaction. It facilitates the formation of the cyclic acetal by protonating the carbonyl oxygen, making the carbonyl carbon more electrophilic and susceptible to nucleophilic attack by ethylene glycol.
Describe the mechanism of the reaction: The reaction proceeds as follows: (1) Protonation of the carbonyl oxygen by TsOH, (2) Nucleophilic attack by one of the hydroxyl groups of ethylene glycol on the carbonyl carbon, forming a hemiacetal intermediate, (3) Loss of water to form a carbocation intermediate, and (4) Intramolecular attack by the second hydroxyl group of ethylene glycol, resulting in the formation of a five-membered cyclic acetal.
Predict the product: The product of this reaction is a five-membered cyclic acetal derived from cyclohexanone and ethylene glycol. This acetal is stable under acidic conditions and serves as a protected form of the ketone, preventing it from undergoing further reactions at the carbonyl group.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Cyclohexanone Reactivity
Cyclohexanone is a cyclic ketone that can undergo various reactions due to its carbonyl group. The reactivity of the carbonyl allows it to participate in nucleophilic addition reactions, where nucleophiles attack the electrophilic carbon of the carbonyl, leading to the formation of alcohols or other functional groups.
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Reactivity of Molecules
Acid-Catalyzed Reactions
In the presence of an acid catalyst, such as p-toluenesulfonic acid, the reactivity of the carbonyl compound is enhanced. The acid protonates the carbonyl oxygen, increasing the electrophilicity of the carbonyl carbon, which facilitates nucleophilic attack by other reagents, such as ethylene glycol in this case.
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Formation of Acetals
When a carbonyl compound reacts with a diol like ethylene glycol in an acid-catalyzed environment, it can form an acetal. This reaction involves the nucleophilic attack of the diol on the carbonyl carbon, followed by the elimination of water, resulting in a stable acetal structure that can be useful in organic synthesis.
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Related Practice
Textbook Question
Predict the products formed when cyclohexanone reacts with the following reagents.
(e) phenylhydrazine and weak acid
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Textbook Question
Predict the products formed when cyclohexanone reacts with the following reagents.
(c) hydroxylamine and weak acid
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Textbook Question
Predict the products formed when cyclohexanone reacts with the following reagents.
(a) CH3NH2, H+
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Textbook Question
Predict the products formed when cyclohexanone reacts with the following reagents.
(f) PhMgBr and then mild H3O+
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Textbook Question
Predict the products formed when cyclohexanone reacts with the following reagents.
g. Tollens reagent
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