Textbook Question
A student, when solving the following 'predict-the-product' question, made a common mistake by writing the answer shown here. Explain why this reaction would not work as written.
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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 20c
Mullins 1st EditionCh. 17 - Carbonyl Addition Reactions: Aldehydes and KetonesProblem 20cChapter 16, Problem 20c
Suggest an acetylide ion and a carbonyl that might be used to make the following products.
(c) 5-phenylhex-2-yn-1-ol
Verified step by step guidance1
Step 1: Recognize that the product, 5-phenylhex-2-yn-1-ol, contains a terminal alcohol (-OH group) and a triple bond (-C≡C-) in the structure. This suggests that the reaction involves the addition of an acetylide ion to a carbonyl compound.
Step 2: Identify the acetylide ion needed. The acetylide ion must contribute the triple bond and part of the carbon chain. In this case, the acetylide ion should be phenylethynide (C₆H₅-C≡C⁻), as it provides the phenyl group and the triple bond.
Step 3: Determine the carbonyl compound. The carbonyl compound must provide the remaining carbon chain and the terminal alcohol group after the reaction. For this product, the carbonyl compound should be propanal (CH₃-CH₂-CHO), as it contributes the three-carbon chain ending in an aldehyde group.
Step 4: Understand the reaction mechanism. The acetylide ion (C₆H₅-C≡C⁻) acts as a nucleophile and attacks the electrophilic carbon of the aldehyde group in propanal (CH₃-CH₂-CHO). This forms a new carbon-carbon bond.
Step 5: After the nucleophilic addition, the intermediate is protonated to yield the final product, 5-phenylhex-2-yn-1-ol. This protonation step typically occurs in the presence of water or a mild acid.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Acetylide Ion
An acetylide ion is a negatively charged species formed by deprotonating a terminal alkyne. It is a strong nucleophile, capable of attacking electrophilic carbon centers, such as those found in carbonyl compounds. In organic synthesis, acetylide ions are often used to form carbon-carbon bonds, making them essential for constructing complex molecules.
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Metal Ion Catalysis Concept 1
Carbonyl Compounds
Carbonyl compounds contain a carbon atom double-bonded to an oxygen atom (C=O). They include aldehydes and ketones, which are key intermediates in organic synthesis. The electrophilic nature of the carbonyl carbon allows it to react with nucleophiles, such as acetylide ions, facilitating the formation of alcohols and other functional groups in multi-step synthesis.
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Alkyne to Alcohol Conversion
The conversion of alkynes to alcohols typically involves nucleophilic addition reactions. In this context, an acetylide ion can react with a carbonyl compound to form an intermediate, which can then be protonated to yield an alcohol. This transformation is crucial for synthesizing alcohols with specific structures, such as the target product 5-phenylhex-2-yn-1-ol.
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Related Practice
Textbook Question
Suggest a carbonyl to react with NaCN/HCN to produce the following cyanohydrins.
(a)
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Textbook Question
Suggest an acetylide ion and a carbonyl that might be used to make the following products.
(a) oct-4-yn-3-ol
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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
Suggest an acetylide ion and a carbonyl that might be used to make the following products.
(b) 2,6-dimethylhept-3-yn-2-ol
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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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