Textbook Question
Show how the following ketones might be synthesized from the indicated acids, using any necessary reagents.
(a) propiophenone from propionic acid (using alkylation of the acid)
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Ch. 20 - Carboxylic Acids
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 20, Problem 21b
Show how the following ketones might be synthesized from the indicated acids, using any necessary reagents.
(b) methyl cyclohexyl ketone from cyclohexanecarboxylic acid
Verified step by step guidance1
Step 1: Recognize that the transformation involves converting a carboxylic acid (cyclohexanecarboxylic acid) into a ketone (methyl cyclohexyl ketone). This typically requires a decarboxylation step followed by an alkylation reaction.
Step 2: Begin by converting the carboxylic acid group (-COOH) into an acyl chloride (-COCl). This can be achieved using reagents such as thionyl chloride (SOCl₂) or oxalyl chloride. The reaction proceeds as: .
Step 3: Perform a Friedel-Crafts acylation reaction to introduce the methyl group. React the acyl chloride with methylbenzene (toluene) in the presence of a Lewis acid catalyst such as aluminum chloride (AlCl₃). This step forms the desired ketone:
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Ketone Synthesis
Ketones can be synthesized through various methods, including oxidation of secondary alcohols, Friedel-Crafts acylation, and the reaction of carboxylic acids with organometallic reagents. Understanding these pathways is crucial for determining how to convert a given acid into a ketone. In this case, the transformation of cyclohexanecarboxylic acid into methyl cyclohexyl ketone requires knowledge of the appropriate reagents and reaction conditions.
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02:27
Name the ketone
Carboxylic Acids
Carboxylic acids are organic compounds characterized by the presence of a carboxyl group (-COOH). They serve as important starting materials in organic synthesis due to their reactivity, particularly in nucleophilic acyl substitution reactions. In the context of this question, cyclohexanecarboxylic acid is the precursor that will undergo transformation to yield the desired ketone.
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04:20Carboxylic Acids Nomenclature
Nucleophilic Acyl Substitution
Nucleophilic acyl substitution is a fundamental reaction mechanism in organic chemistry where a nucleophile attacks the carbonyl carbon of a carboxylic acid derivative, leading to the substitution of the leaving group. This mechanism is essential for converting carboxylic acids into ketones, as it allows for the introduction of new alkyl groups. Understanding this mechanism will help in planning the synthesis of methyl cyclohexyl ketone from cyclohexanecarboxylic acid.
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01:47Nucleophiles and Electrophiles can react in Substitution Reactions.
Related Practice
Textbook Question
Propose mechanisms for the nucleophilic acyl substitutions to form ethyl benzoate as shown on the previous page.
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Textbook Question
Propose mechanisms for the nucleophilic acyl substitutions to form N-methylacetamide as shown on the previous page.
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Textbook Question
Propose a mechanism for the reaction of benzoic acid with oxalyl chloride. This mechanism begins like the thionyl chloride reaction, to give a reactive mixed anhydride. Nucleophilic acyl substitution by chloride ion gives a tetrahedral intermediate that eliminates a leaving group, which then fragments into carbon dioxide, carbon monoxide, and chloride ion.
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Textbook Question
Draw the following sugars using Haworth projections:
b. α-D-tagatopyranose
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