Textbook Question
Show the product expected by the Wolff–Kishner reduction of the following aldehydes/ketones.
(a)
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Ch. 17 - Carbonyl Addition Reactions: Aldehydes and Ketones
Mullins1st EditionOrganic Chemistry: A Learner Centered ApproachISBN: 9780137566471
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Table of contents
- Ch. 2 - General Chemistry Translated: Finding the Electrons114
- Ch. 3 - Alkanes and Cycloalkanes: Properties and Conformational Analysis109
- Ch. 4 - Acids and Bases: Electron Flow144
- Ch. 5 - Chemical Reaction Analysis: Thermodynamics and Kinetics118
- Ch. 6 - Stereoisomerism: Arrangement of Atoms in Space112
- Ch. 7 - Principles of Green (Organic) Chemistry3
- Ch. 8 - Alkenes I: Properties and Electrophilic Additions158
- Ch. 9 - Alkenes II: Oxidation and Reduction150
- Ch. 10 - Alkynes: Electrophilic Addition and Redox Reactions101
- Ch. 11 - Properties and Synthesis of Alkyl Halides: Radical Reactions108
- Ch. 12 - Substitution and Elimination: Reactions of Haloalkanes172
- Ch. 13 - Alcohols, Ethers and Related Compounds: Substitution and Elimination239
- Ch. 14 - Structural Identification I: Infrared Spectroscopy and Mass Spectrometry54
- Ch. 15 - Structural Identification II: Nuclear Magnetic Resonance Spectroscopy93
- Ch. 16 - Metals in Organic Chemistry48
- Ch. 17 - Carbonyl Addition Reactions: Aldehydes and Ketones45
- Ch. 18 - Nucleophilic Acyl Substitution I: Carboxylic Acids18
- Ch. 19 - Nucleophilic Acyl Substitution II: Carboxylic Acid Derivatives39
- Ch. 20 - Enolates: Carbonyl Addition and Substitution13
- Ch. 21 - Conjugated Systems I: Stability and Addition Reactions56
- Ch. 22 - Conjugated Systems II: Pericyclic Reactions54
- Ch. 23 - Benzene I: Aromatic Stability and Substitution Reactions64
- Ch. 24 - Benzene II: Reactions Influenced by the Aromatic Ring62
- Ch. 25 - Amines: Structure, Reactions, and Synthesis27
- Ch. 26 - Amino Acids, Proteins, and Peptide Synthesis9
- Ch. 27 - Carbohydrates, Nucleic Acids, and Lipids54
Mullins1st EditionOrganic Chemistry: A Learner Centered ApproachISBN: 9780137566471Not the one you use?Change textbook
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Mullins 1st EditionCh. 17 - Carbonyl Addition Reactions: Aldehydes and KetonesProblem 32a
Mullins 1st EditionCh. 17 - Carbonyl Addition Reactions: Aldehydes and KetonesProblem 32aChapter 16, Problem 32a
Provide a mechanism for the formation of the hemiacetals shown. [Only (c) is favored as written.]
(a) 
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Identify the reactants involved in the formation of a hemiacetal. Typically, a hemiacetal is formed from an aldehyde or ketone reacting with an alcohol.
Recognize the functional groups present in the reactants. The carbonyl group (C=O) in the aldehyde or ketone is the electrophile, while the hydroxyl group (OH) in the alcohol acts as the nucleophile.
Initiate the mechanism by protonating the carbonyl oxygen to make the carbonyl carbon more electrophilic. This is often facilitated by an acid catalyst.
The nucleophilic attack occurs when the alcohol's oxygen atom donates a pair of electrons to the electrophilic carbonyl carbon, forming a new C-O bond.
Complete the mechanism by deprotonating the oxygen atom of the alcohol, resulting in the formation of the hemiacetal. The structure now contains both an alcohol and an ether functional group on the same carbon.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Hemiacetal Formation
Hemiacetals are formed when an alcohol reacts with an aldehyde or ketone. This reaction involves the nucleophilic attack of the alcohol's hydroxyl group on the carbonyl carbon, leading to the formation of a tetrahedral intermediate. The subsequent proton transfer and loss of water yield the hemiacetal, which contains both an alcohol and an ether functional group.
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Equilibrium and Favorability
The formation of hemiacetals is an equilibrium process, meaning that both the reactants and products can coexist. The position of this equilibrium can be influenced by factors such as concentration, temperature, and the nature of the reactants. In the context of the question, understanding which hemiacetal is favored requires analyzing these factors and the stability of the resulting structures.
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Mechanistic Steps
The mechanism for hemiacetal formation involves several key steps: nucleophilic attack, formation of a tetrahedral intermediate, proton transfer, and elimination of water. Each step is crucial for understanding how the reaction proceeds and how the structure of the hemiacetal is established. A clear grasp of these mechanistic steps is essential for predicting the outcome of the reaction and the stability of the products.
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Related Practice
Textbook Question
During an oxidation reaction, there must also be a reduction. What is reduced in the Pinnick oxidation?
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Textbook Question
Identify the hemiacetal functional group in each of the following molecules. These molecules may not be stable enough to be the favorable product in an equilibrium reaction.
(c)
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Textbook Question
Suggest the appropriate carbonyl and Wittig reagent to make the following alkenes.
a. (E)-7-methylnon-4-en-3-one
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Textbook Question
Which of the following cyclic hemiacetals would you expect to have the highest Keq for their formation? Explain your answer.
(a)
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Textbook Question
For each of the following carbonyl addition reactions, would you expect a racemic mixture or a mixture enriched in one stereoisomer? In each case, draw both possible stereoisomeric products.
(a)
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