Textbook Question
Write the mechanism for the acid-catalyzed reaction of an amide with an alcohol to form an ester.
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Ch. 15 - Reactions of Carboxylic Acids and Carboxylic Acid Derivatives
Bruice8th EditionOrganic ChemistryISBN: 9780135213711
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Table of contents
- Ch. 1 - Remembering General Chemistry: Electronic Structure and Bonding (Part 1)31
- Ch. 1 - Remembering General Chemistry: Electronic Structure and Bonding (Part 2)65
- 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
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Bruice 8th EditionCh. 15 - Reactions of Carboxylic Acids and Carboxylic Acid DerivativesProblem 32
Bruice 8th EditionCh. 15 - Reactions of Carboxylic Acids and Carboxylic Acid DerivativesProblem 32Chapter 16, Problem 32
Propose a mechanism for the following reaction. (Hint: Number the carbons to help you see where they end up in the product.)
Verified step by step guidance1
Step 1: Analyze the reactants and conditions. The starting material is a conjugated diene, and the reaction occurs in the presence of sulfuric acid (H2SO4), which acts as a strong acid and proton donor. This suggests an electrophilic addition mechanism.
Step 2: Protonation of the diene. The sulfuric acid donates a proton (H+) to one of the double bonds in the conjugated diene, forming a carbocation intermediate. Number the carbons in the diene to track the movement of atoms during the reaction.
Step 3: Resonance stabilization of the carbocation. The carbocation formed can undergo resonance, redistributing the positive charge across the conjugated system. This step is crucial for determining the most stable carbocation intermediate.
Step 4: Nucleophilic attack by water. Water (H2O), present in the reaction mixture, acts as a nucleophile and attacks the carbocation, forming an alcohol intermediate.
Step 5: Deprotonation to form the final product. The alcohol intermediate loses a proton (H+) to regenerate the acidic environment and form the final product, which is a hydrated ketone or aldehyde depending on the position of the carbocation.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Fischer Esterification
Fischer esterification is a chemical reaction that forms an ester from a carboxylic acid and an alcohol in the presence of an acid catalyst, typically sulfuric acid. The reaction involves the nucleophilic attack of the alcohol on the carbonyl carbon of the carboxylic acid, leading to the formation of a tetrahedral intermediate, which subsequently loses a water molecule to yield the ester.
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Mechanism of Reaction
Understanding the mechanism of a reaction involves breaking down the steps that occur during the transformation of reactants to products. In Fischer esterification, the mechanism includes protonation of the carbonyl oxygen, nucleophilic attack by the alcohol, formation of the tetrahedral intermediate, and elimination of water. Each step is crucial for predicting the outcome and understanding the reaction conditions.
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Role of Acid Catalyst
An acid catalyst, such as H2SO4, plays a vital role in Fischer esterification by protonating the carbonyl oxygen of the carboxylic acid, increasing its electrophilicity. This enhances the reactivity of the carbonyl carbon, making it more susceptible to nucleophilic attack by the alcohol. The presence of the acid catalyst also helps to drive the equilibrium towards ester formation by removing water from the reaction mixture.
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Related Practice
Textbook Question
Show how each of the following esters could be prepared using a carboxylic acid as one of the starting materials:
a. methyl butyrate (odor of apples)
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Textbook Question
Which of the following reactions lead to the formation of an amide?
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Textbook Question
D. N. Kursanov, a Russian chemist, proved that the bond that is broken in the hydroxide-ion-promoted hydrolysis of an ester is the acyl C—O bond, rather than the alkyl C—O bond, by studying the hydrolysis of the following ester under basic conditions:
a. What products contained the 18O label?
b. What product would have contained the 18O label if the alkyl C—O bond had broken?
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Textbook Question
b. Explain why the rate of aminolysis of an ester cannot be increased by HO−, or RO−.
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Textbook Question
What acyl chloride and amine are required to synthesize the following amides?
a. N-ethylbutanamide
b. N,N-dimethylbenzamide
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