Textbook Question
Draw the products of the following reactions:
d. diethyl 1,2-benzenedicarboxylate + sodium ethoxide: (1) slow addition of ethyl acetate; (2) HCl
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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 49e
Draw the products of the following reactions: e. diethyl malonate: (1) sodium ethoxide; (2) isobutyl bromide; (3) HCl, H2O + heat
Verified step by step guidance1
Step 1: Analyze the starting material, diethyl malonate. It contains two ester groups and a methylene group (-CH2-) between them, which is acidic due to the electron-withdrawing effects of the ester groups. This makes the methylene hydrogens susceptible to deprotonation by a base.
Step 2: In the first step, sodium ethoxide (CH3CH2ONa) acts as a strong base to deprotonate the methylene group of diethyl malonate, forming a carbanion. This carbanion is stabilized by resonance with the two ester groups.
Step 3: In the second step, the carbanion undergoes nucleophilic substitution with isobutyl bromide. The carbanion attacks the electrophilic carbon in the isobutyl bromide, displacing the bromide ion and forming a new C-C bond. This results in an alkylated diethyl malonate derivative.
Step 4: In the third step, the reaction mixture is treated with HCl, H2O, and heat. Under these conditions, the ester groups undergo hydrolysis to form carboxylic acids. The intermediate then undergoes decarboxylation (loss of CO2) due to heating, leaving behind a single carboxylic acid product.
Step 5: The final product is a substituted carboxylic acid where the original methylene group has been alkylated with the isobutyl group. The decarboxylation step ensures that only one carboxylic acid group remains in the product.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Malonic Ester Synthesis
Malonic ester synthesis is a method for synthesizing carboxylic acids through the alkylation of diethyl malonate. In this reaction, diethyl malonate is first deprotonated by a strong base, such as sodium ethoxide, to form a nucleophilic enolate. This enolate can then react with an alkyl halide, such as isobutyl bromide, to form a substituted malonic ester, which can be hydrolyzed and decarboxylated to yield the desired carboxylic acid.
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Enolate Formation
Enolate formation is a crucial step in many organic reactions, particularly in malonic ester synthesis. When a compound with an acidic hydrogen, like diethyl malonate, is treated with a strong base, it loses a proton to form an enolate ion. This enolate is a resonance-stabilized species that can act as a nucleophile, allowing it to attack electrophiles such as alkyl halides, facilitating the formation of new carbon-carbon bonds.
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Hydrolysis and Decarboxylation
Hydrolysis and decarboxylation are key processes that follow the alkylation step in malonic ester synthesis. After the alkylation, the product is treated with acid and water, leading to hydrolysis, which converts the ester into a carboxylic acid. Subsequently, heating the carboxylic acid can induce decarboxylation, where carbon dioxide is released, resulting in the formation of a more stable product, typically a ketone or a simple carboxylic acid.
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Related Practice
Textbook Question
Which of the following compounds decarboxylates when heated?
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Textbook Question
Draw the products of the following reactions:
c. acetone + LDA/THF: (1) slow addition of ethyl acetate; (2) HCl
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Textbook Question
The 1H NMR chemical shifts of nitromethane, dinitromethane, and trinitromethane are at δ6.10, δ4.33, and δ7.52. Match each chemical shift with the compound. Explain how chemical shift correlates with pKa.
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Textbook Question
Draw the products of the following reactions:
a. diethyl heptanedioate: (1) sodium ethoxide; (2) HCl
1583
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Textbook Question
Draw the products of the following reactions: b. pentanoic acid + PBr3 + Br2, followed by hydrolysis
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