Textbook Question
How could each of the following compounds be prepared from a ketone and an alkyl halide?
a.
4
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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 11a
Show how the following compounds can be prepared from the given starting material:
a. 
Verified step by step guidance1
Step 1: Analyze the starting material, 3-methylbutanoate, and the target compound, 3-methyl-2-(methylthio)butanoate. Notice that the target compound has a methylthio (-SCH3) group added to the alpha-carbon (the carbon adjacent to the carbonyl group). This suggests a nucleophilic substitution or addition reaction at the alpha-carbon.
Step 2: To activate the alpha-carbon for substitution, perform an alpha-halogenation reaction. Treat the starting material with a halogen (e.g., Br2 or Cl2) in the presence of a base (e.g., NaOH). This will replace one of the alpha-hydrogens with a halogen atom, forming 3-methyl-2-halo-butanoate.
Step 3: Introduce the methylthio group (-SCH3) by performing a nucleophilic substitution reaction. Use a nucleophile such as sodium methanethiolate (NaSCH3) to replace the halogen atom at the alpha-carbon with the methylthio group. This step converts 3-methyl-2-halo-butanoate into 3-methyl-2-(methylthio)butanoate.
Step 4: Ensure the reaction conditions are mild to avoid side reactions. For example, use an appropriate solvent like ethanol or acetone to facilitate the nucleophilic substitution reaction.
Step 5: Purify the product using techniques such as distillation or recrystallization to isolate 3-methyl-2-(methylthio)butanoate in its pure form.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Nucleophilic Substitution
Nucleophilic substitution is a fundamental reaction mechanism in organic chemistry where a nucleophile attacks an electrophile, resulting in the replacement of a leaving group. In the context of the given reaction, the nucleophile (methylthio group) attacks the carbon atom of the 3-methylbutanoate that is bonded to the leaving group, facilitating the formation of the desired product.
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Nucleophiles and Electrophiles can react in Substitution Reactions.
Carboxylic Acid Derivatives
Carboxylic acid derivatives, such as esters and thioesters, are compounds that can be derived from carboxylic acids by replacing the hydroxyl group with another functional group. Understanding these derivatives is crucial for predicting the reactivity and transformation of compounds like 3-methylbutanoate into 3-methyl-2-(methylthio)butanoate, as they often undergo nucleophilic substitution reactions.
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Reaction Mechanisms
A reaction mechanism describes the step-by-step process by which reactants are converted into products, detailing the formation and breaking of bonds. In this case, analyzing the mechanism of the nucleophilic substitution will help in understanding how the methylthio group is introduced into the 3-methylbutanoate structure, leading to the formation of the target compound.
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Related Practice
Textbook Question
How could each of the following compounds be prepared from cyclohexanone?
a.
1
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Textbook Question
Draw the enol tautomers for each of the following compounds. For compounds that have more than one enol tautomer, indicate the one that is more stable.
f.
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Textbook Question
Draw the enol tautomers for each of the following compounds. For compounds that have more than one enol tautomer, indicate the one that is more stable.
d.
e.
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Textbook Question
A ketone undergoes acid-catalyzed bromination, acid-catalyzed chlorination, racemization, and acid-catalyzed deuterium exchange at the ⍺-carbon. All of these reactions have similar rate constants.What does this tell you about the mechanisms of these reactions?
2
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Textbook Question
How could each of the following compounds be prepared from a ketone and an alkyl halide?
b.
4
views