Textbook Question
What alkyl bromide should be used in the acetoacetic ester synthesis of each of the following methyl ketones? b. 2-octanone
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Ch. 17 - Reactions at the Alpha-Carbon
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
Chapter 18, Problem 41a
What alkyl bromide should be used in the acetoacetic ester synthesis of each of the following methyl ketones? a. 2-pentanone
Verified step by step guidance1
Step 1: Understand the acetoacetic ester synthesis. This reaction involves the alkylation of ethyl acetoacetate (a β-keto ester) followed by hydrolysis and decarboxylation to produce a methyl ketone. The key step is identifying the alkyl bromide that will introduce the desired alkyl group to the β-keto ester.
Step 2: Analyze the target molecule, 2-pentanone. The structure of 2-pentanone is CH3-CO-CH2-CH2-CH3. This indicates that the methyl ketone has a CH3 group on one side of the carbonyl and a CH2CH2CH3 group on the other side.
Step 3: Recognize that the CH3 group comes from the ethyl acetoacetate itself. The remaining CH2CH2CH3 group must be introduced via alkylation using an appropriate alkyl bromide.
Step 4: Determine the alkyl bromide needed. To add the CH2CH2CH3 group, the alkyl bromide should be 1-bromopropane (CH3CH2CH2Br). This will react with the enolate of ethyl acetoacetate during the alkylation step.
Step 5: Summarize the process. The synthesis involves deprotonating ethyl acetoacetate to form the enolate, reacting it with 1-bromopropane to introduce the CH2CH2CH3 group, and then performing hydrolysis and decarboxylation to yield 2-pentanone.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Acetoacetic Ester Synthesis
Acetoacetic ester synthesis is a method for forming ketones through the reaction of an acetoacetic ester with an alkyl halide. This reaction involves the nucleophilic substitution of the ester enolate with the alkyl halide, leading to the formation of a new carbon-carbon bond. Understanding this process is crucial for determining the appropriate alkyl bromide to use for synthesizing specific ketones.
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Enolate Formation
Enolate formation is a key step in acetoacetic ester synthesis, where a base abstracts a proton from the alpha carbon of the acetoacetic ester, generating a resonance-stabilized enolate ion. This enolate can act as a nucleophile, attacking the electrophilic carbon of the alkyl halide. Recognizing how to generate and utilize enolates is essential for predicting the outcome of the synthesis.
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Alkyl Halides
Alkyl halides, such as alkyl bromides, are organic compounds containing a carbon atom bonded to a halogen atom. The choice of alkyl halide in acetoacetic ester synthesis affects the structure of the resulting ketone. Understanding the reactivity and structure of different alkyl halides is important for selecting the correct one to achieve the desired methyl ketone from the synthesis.
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Related Practice
Textbook Question
Design a synthesis for each of the following compounds using the given starting material:
b.
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Textbook Question
What alkyl bromide(s) should be used in the malonic ester synthesis of each of the following carboxylic acids?
a. propanoic acid
b. 2-methylpropanoic acid
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Textbook Question
What alkyl bromide should be used in the acetoacetic ester synthesis of each of the following methyl ketones? c. 4-phenyl-2-butanone
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Textbook Question
Which of the following compounds will decarboxylate when heated?
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Textbook Question
Explain why the following carboxylic acids cannot be prepared by a malonic ester synthesis:
c.
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