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Draw structures for A-D for each of the following:
b.
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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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TOC.tableOfContents
- Ch. 1 - Remembering General Chemistry: Electronic Structure and Bonding31
- 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 DerivativesProblema 82
Bruice 8th EditionCh. 16 - Reactions of Aldehydes and Ketones • More Reactions of Carboxylic Acid DerivativesProblema 82Capitolo 16, Problema 82
Unlike a phosphonium ylide that reacts with an aldehyde or a ketone to form an alkene, a sulfonium ylide reacts with an aldehyde or a ketone to form an epoxide. Explain why one ylide forms an alkene, whereas the other forms an epoxide.
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Understand the structure of the ylides: A phosphonium ylide contains a positively charged phosphorus atom bonded to a carbon atom with a lone pair of electrons, while a sulfonium ylide contains a positively charged sulfur atom bonded to a carbon atom with a lone pair of electrons.
Analyze the reactivity of the ylides: Phosphonium ylides are more nucleophilic and less electrophilic compared to sulfonium ylides due to the difference in electronegativity between phosphorus and sulfur. Sulfur is more electronegative, making sulfonium ylides more electrophilic and less nucleophilic.
Consider the reaction mechanism for phosphonium ylides: Phosphonium ylides react with aldehydes or ketones via the Wittig reaction. The nucleophilic carbon of the ylide attacks the carbonyl carbon, forming a betaine intermediate, which rearranges to produce an alkene and a triphenylphosphine oxide byproduct.
Consider the reaction mechanism for sulfonium ylides: Sulfonium ylides react with aldehydes or ketones via a different pathway. The electrophilic sulfur atom stabilizes the intermediate, leading to a concerted cyclization reaction that forms a three-membered epoxide ring.
Summarize the key difference: The difference in product formation arises from the nature of the ylide and the reaction mechanism. Phosphonium ylides favor the formation of alkenes due to their nucleophilicity and the Wittig reaction pathway, while sulfonium ylides favor the formation of epoxides due to their electrophilicity and the stabilization of the cyclization intermediate.
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Ylide Chemistry
Ylides are neutral molecules containing a positively charged atom adjacent to a negatively charged atom, typically involving phosphorus or sulfur. In organic reactions, ylides can act as nucleophiles, attacking electrophiles such as carbonyl compounds. The nature of the ylide, whether phosphonium or sulfonium, influences the type of reaction it undergoes with aldehydes or ketones.
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Introduction to General Chemistry Review
Mechanism of Alkene Formation
Phosphonium ylides react with aldehydes or ketones through a mechanism known as the Wittig reaction, which involves the formation of an intermediate that ultimately leads to the elimination of a phosphine oxide and the formation of an alkene. This reaction is characterized by the formation of a carbon-carbon double bond, which is a key feature of the Wittig reaction, making it a powerful tool in organic synthesis.
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Percorso guidato
1:59Alkene Metathesis Concept 5
Epoxide Formation
Sulfoniun ylides react with carbonyl compounds to form epoxides through a different mechanism that involves a cyclic transition state. This reaction typically proceeds via a nucleophilic attack on the carbonyl carbon, followed by intramolecular closure to form a three-membered epoxide ring. The unique electronic properties of the sulfonium ylide facilitate this pathway, distinguishing it from the alkene-forming reaction of phosphonium ylides.
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02:19General properties of epoxidation.
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