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 55a
Draw the products of the following reactions:
a. 
Verified step by step guidance1
Step 1: Identify the starting material, which is a ketone with a cyclopentane ring and a methyl group attached to the carbonyl carbon.
Step 2: Recognize the reagents used in the reaction. LDA (Lithium Diisopropylamide) is a strong, non-nucleophilic base, and THF (tetrahydrofuran) is the solvent. The reaction is performed at -78°C, which favors kinetic enolate formation.
Step 3: Understand the mechanism. LDA will deprotonate the most accessible alpha-hydrogen (hydrogen on the carbon adjacent to the carbonyl group) to form the kinetic enolate. The kinetic enolate is formed on the less substituted alpha-carbon due to steric hindrance.
Step 4: Analyze the second step. D₂O (deuterium oxide) is added, which will replace the enolate's alpha-hydrogen with a deuterium atom through protonation of the enolate intermediate.
Step 5: Draw the product. The final product will be the original ketone structure with a deuterium atom replacing the alpha-hydrogen on the less substituted alpha-carbon.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Enolate Formation
Enolate formation is a key reaction in organic chemistry where a base abstracts a proton from an alpha carbon of a carbonyl compound, resulting in the formation of an enolate ion. This ion is resonance-stabilized and can act as a nucleophile in subsequent reactions. In the given reaction, LDA (Lithium diisopropylamide) is used as a strong base to generate the enolate at low temperatures, which is crucial for controlling the reaction pathway.
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02:26
Formation of Enolates
Aldol Reaction
The aldol reaction involves the condensation of two carbonyl compounds, typically aldehydes or ketones, to form a β-hydroxy carbonyl compound. In this case, the enolate formed in the first step can attack another carbonyl carbon, leading to the formation of a new carbon-carbon bond. This reaction is fundamental in building complex organic molecules and is often followed by dehydration to yield α,β-unsaturated carbonyl compounds.
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09:51Crossed Aldol
Deuterium Incorporation
Deuterium incorporation refers to the introduction of deuterium (D or ²H), a stable isotope of hydrogen, into organic molecules. In the second step of the reaction, D₂O is used, allowing the enolate to react with deuterium instead of regular hydrogen. This process is significant in labeling studies and mechanistic investigations, as it can provide insights into reaction pathways and the behavior of intermediates.
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03:06Understanding the hydrogen isotopes.
Related Practice
Textbook Question
An aldol addition can be catalyzed by acids as well as by bases. Propose a mechanism for the acid-catalyzed aldol addition of propanal.
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Textbook Question
Draw the products of the following reactions:
b.
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Textbook Question
Which of the following compounds decarboxylates when heated?
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Textbook Question
In the presence of excess base and excess halogen, a methyl ketone is converted to a carboxylate ion. The reaction is known as the haloform reaction because one of the products is haloform (chloroform, bromoform, or iodoform). Before spectroscopy became a routine analytical tool, the haloform reaction served as a test for methyl ketones: the formation of iodoform, a bright yellow compound, signaled that a methyl ketone was present. Why do only methyl ketones form a haloform?
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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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