Textbook Question
How can the following compounds be prepared from the given starting materials?
c.
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Ch. 16 - Reactions of Aldehydes and Ketones • More Reactions of Carboxylic Acid Derivatives
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
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Bruice 8th EditionCh. 16 - Reactions of Aldehydes and Ketones • More Reactions of Carboxylic Acid DerivativesProblem 85a
Bruice 8th EditionCh. 16 - Reactions of Aldehydes and Ketones • More Reactions of Carboxylic Acid DerivativesProblem 85aChapter 17, Problem 85a
Propose a mechanism for each of the following reactions:
a. 
Verified step by step guidance1
Step 1: Analyze the starting material and reagent. The starting material is a ketone attached to a cyclohexane ring with a phenyl group and an ethyl group. The reagent is concentrated sulfuric acid (H₂SO₄), which acts as a strong acid and catalyst for protonation and rearrangement reactions.
Step 2: Protonation of the ketone group. The oxygen atom in the ketone is protonated by H₂SO₄, forming a positively charged oxonium ion. This increases the electrophilicity of the carbonyl carbon, making it susceptible to nucleophilic attack or rearrangement.
Step 3: Formation of a carbocation intermediate. The protonated ketone undergoes a rearrangement where the bond between the carbonyl carbon and the adjacent carbon breaks, leading to the formation of a carbocation at the benzylic position (the carbon attached to the phenyl group). This carbocation is stabilized by resonance with the phenyl ring.
Step 4: Rearrangement and aromaticity restoration. The carbocation undergoes a hydride shift or alkyl shift to form a more stable aromatic intermediate. This step restores the aromaticity of the benzene ring and positions the phenyl and ethyl groups appropriately.
Step 5: Deprotonation to form the final product. A water molecule or another base removes a proton from the hydroxyl group, resulting in the formation of the final product: a phenol derivative with the phenyl and ethyl groups attached to the aromatic ring.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Tautomerization
Tautomerization is a chemical reaction that involves the interconversion of two isomers, typically involving the migration of a hydrogen atom and a switch of a double bond. In organic chemistry, this often occurs between a keto form and an enol form. Understanding this concept is crucial for analyzing reactions where structural rearrangements take place, as seen in the provided reaction.
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Tautomerization Mechanisms
Acid-Catalyzed Reactions
Acid-catalyzed reactions involve the use of an acid, such as sulfuric acid (H2SO4), to facilitate the transformation of reactants into products. The acid can protonate functional groups, making them more reactive and promoting rearrangements or eliminations. Recognizing the role of the acid in the mechanism is essential for predicting the outcome of the reaction shown.
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Electrophilic Aromatic Substitution
Electrophilic aromatic substitution (EAS) is a fundamental reaction in organic chemistry where an electrophile replaces a hydrogen atom on an aromatic ring. This process is significant in the context of the reaction, as the presence of the phenyl groups suggests that the aromatic system may be involved in stabilizing intermediates during tautomerization. Understanding EAS helps in predicting how substituents on the aromatic ring will influence the reaction pathway.
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Related Practice
Textbook Question
How can the following compounds be prepared from the given starting materials?
d.
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Textbook Question
Shown below is the 1H NMR spectrum of the alkyl bromide used to make the phosphonium ylide that reacts with a ketone in a Wittig reaction to form a compound with molecular formula C11H14. What product is obtained from the Wittig reaction?
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Textbook Question
In an aqueous solution, D-glucose exists in equilibrium with two six-membered ring compounds. Draw the structures of these compounds.
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Textbook Question
How can the following compounds be prepared from the given starting materials?
b.
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Textbook Question
Propose a mechanism for each of the following reactions:
b.
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