Textbook Question
Design a synthesis for each of the following compounds using the given starting material:
b.
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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 41b
What alkyl bromide should be used in the acetoacetic ester synthesis of each of the following methyl ketones? b. 2-octanone
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-octanone. The structure of 2-octanone consists of a ketone group on the second carbon of an eight-carbon chain. This means the methyl ketone is derived from ethyl acetoacetate by adding a six-carbon chain to the α-carbon of the β-keto ester.
Step 3: Determine the alkyl group needed. To form 2-octanone, the ethyl acetoacetate must be alkylated with a six-carbon alkyl group. This alkyl group will come from the alkyl bromide used in the reaction.
Step 4: Identify the appropriate alkyl bromide. The alkyl bromide should have a six-carbon chain and no branching at the carbon attached to the bromine atom. This ensures a straightforward substitution reaction. The correct alkyl bromide is 1-bromohexane (C6H13Br).
Step 5: Summarize the reaction. In the acetoacetic ester synthesis, ethyl acetoacetate is treated with a base (e.g., sodium ethoxide) to form an enolate ion, which then reacts with 1-bromohexane in an SN2 reaction. Subsequent hydrolysis and decarboxylation yield 2-octanone as the final product.
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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 from acetoacetic ester and an alkyl halide. This reaction involves the nucleophilic substitution of the ester enolate with an alkyl halide, leading to the formation of a β-keto ester. 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 α-carbon of the acetoacetic ester, generating a resonance-stabilized enolate ion. This enolate acts as a nucleophile, allowing it to react with an alkyl halide. Recognizing how to form and utilize enolates is essential for predicting the products of the synthesis.
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Alkyl Halide Selection
The selection of the appropriate alkyl halide is critical in acetoacetic ester synthesis, as it determines the structure of the final ketone product. The alkyl halide must have a carbon chain that, when added to the enolate, results in the desired ketone. Understanding the structure of the target ketone, such as 2-octanone, helps in identifying the correct alkyl bromide to use in the reaction.
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Related Practice
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
Design a synthesis for each of the following compounds using the given starting material:
d.
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Textbook Question
What alkyl bromide should be used in the acetoacetic ester synthesis of each of the following methyl ketones? a. 2-pentanone
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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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