Domanda del libro di testo
Propose mechanisms for the following reactions.
(b)
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Ch. 22 - Condensations and Alpha Substitutions of Carbonyl Compounds
Wade9th EditionOrganic ChemistryISBN: 9780135213728
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TOC.tableOfContents
- Ch.1 - Structure and Bonding107
- Ch. 2 - Acids and Bases; Functional Groups115
- Ch.3 - Structure and Stereochemistry of Alkanes100
- Ch.4 - The Study of Chemical Reactions99
- Ch.5 - Stereochemistry93
- Ch.6 - Alkyl Halides; Nucleophilic Substitution118
- Ch. 7 - Structure and Synthesis of Alkenes; Elimination158
- Ch.8 - Reactions of Alkenes171
- Ch.9 - Alkynes91
- Ch.10 - Structure and Synthesis of Alcohols143
- Ch.11 - Reactions of Alcohols104
- Ch. 12 - Infrared Spectroscopy and Mass Spectrometry22
- Ch. 13 - Nuclear Magnetic Resonance Spectroscopy45
- Ch. 14 - Ethers, Epoxides, and Thioethers72
- Ch. 15 - Conjugated Systems, Orbital Symmetry, and Ultraviolet Spectroscopy89
- Ch. 16 - Aromatic Compounds74
- Ch. 17 - Reactions of Aromatic Compounds126
- Ch. 18 - Ketones and Aldehydes193
- Ch. 19 - Amines129
- Ch. 20 - Carboxylic Acids77
- Ch. 21 - Carboxylic Acid Derivatives141
- Ch. 22 - Condensations and Alpha Substitutions of Carbonyl Compounds175
- Ch. 23 - Carbohydrates and Nucleic Acids93
- Ch. 24 - Amino Acids, Peptides, and Proteins54
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Wade 9th EditionCh. 22 - Condensations and Alpha Substitutions of Carbonyl CompoundsProblema 76
Wade 9th EditionCh. 22 - Condensations and Alpha Substitutions of Carbonyl CompoundsProblema 76Capitolo 22, Problema 76
Predict the products from this sequence of reactions.
Guida verificata passo dopo passo1
Step 1: Analyze the first reaction. The starting compound is a β-keto aldehyde. When treated with NaOH and heat (Δ), an aldol condensation occurs. This reaction involves the deprotonation of the α-hydrogen of the aldehyde group, followed by nucleophilic attack on the ketone group. The product is typically an α,β-unsaturated ketone.
Step 2: Examine the second reaction. The product from the aldol condensation (compound A) reacts with (CH₃)₂CuLi, a Gilman reagent. Gilman reagents are known for their ability to perform conjugate addition (1,4-addition) to α,β-unsaturated carbonyl compounds. The methyl group from the Gilman reagent adds to the β-carbon of the α,β-unsaturated ketone, forming compound B.
Step 3: Consider the third reaction. Compound B reacts with CH₃CH₂Br, an alkyl halide, under conditions likely involving nucleophilic substitution. The enolate form of compound B (generated by deprotonation of the α-hydrogen) acts as a nucleophile and attacks the ethyl bromide, resulting in the formation of compound C.
Step 4: Summarize the transformations. The sequence of reactions involves aldol condensation, conjugate addition, and alkylation. Each step modifies the structure of the original molecule, leading to the final product.
Step 5: Verify the stereochemistry and regiochemistry. Ensure that the conjugate addition and alkylation occur at the correct positions, and confirm that the final product (compound C) is consistent with the expected reaction mechanisms.
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Michael Addition
Michael addition is a nucleophilic addition reaction where a nucleophile adds to an α,β-unsaturated carbonyl compound. In this reaction, the nucleophile attacks the β-carbon, leading to the formation of a new carbon-carbon bond. Understanding this mechanism is crucial for predicting the products of the reaction sequence shown in the question.
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1,2 vs 1,4 Addition
Reagents and Conditions
The choice of reagents and conditions significantly influences the outcome of organic reactions. In this sequence, sodium hydroxide (NaOH) and heat are used to facilitate the Michael addition, while (CH3)2CuLi acts as a nucleophile in the subsequent step. Recognizing how these reagents interact with the substrates is essential for predicting the products A, B, and C.
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01:52Reagents
Stereochemistry and Product Formation
Stereochemistry plays a vital role in determining the structure of the products formed in organic reactions. The orientation of substituents around the newly formed bonds can lead to different stereoisomers. In this reaction sequence, understanding the stereochemical implications of each step is important for accurately predicting the final products.
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Percorso guidato
1:38Polymer Stereochemistry Concept 1
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Domanda del libro di testo
The Knoevenagel condensation is a special case of the aldol condensation in which an active methylene compound reacts with an aldehyde or ketone, in the presence of a secondary amine as a basic catalyst, to produce a new C=C. Show the starting materials that made each of these by a Knoevenagel condensation.
(f)
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Domanda del libro di testo
Propose mechanisms for the following reactions.
(a)
766
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Domanda del libro di testo
The Knoevenagel condensation is a special case of the aldol condensation in which an active methylene compound reacts with an aldehyde or ketone, in the presence of a secondary amine as a basic catalyst, to produce a new C=C. Show the starting materials that made each of these by a Knoevenagel condensation.
(e)
594
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Domanda del libro di testo
The Knoevenagel condensation is a special case of the aldol condensation in which an active methylene compound reacts with an aldehyde or ketone, in the presence of a secondary amine as a basic catalyst, to produce a new C=C. Show the starting materials that made each of these by a Knoevenagel condensation.
(d)
712
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Domanda del libro di testo
Propose mechanisms for the following reactions.
(c)
776
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