Textbook Question
The Eschenmoser–Claisen reaction is a variant of the Claisen reaction studied in this chapter. Based on your answers to Assessments 22.53–22.55, predict a product of this reaction.
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Ch. 22 - Conjugated Systems II: Pericyclic Reactions
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
Chapter 21, Problem 62
The product of the Stille coupling reaction (A) tautomerizes in a basic solution to give compound B. B spontaneously converts to C. (a) Propose a structure for A. (b) Suggest a mechanism for the conversion of A to B.
Verified step by step guidance1
Step 1: Understand the Stille coupling reaction. The Stille coupling is a palladium-catalyzed cross-coupling reaction between an organotin compound (R-SnR3) and an organic halide (R'-X) to form a new carbon-carbon bond. Identify the possible reactants and the product (A) based on the given information.
Step 2: Propose a structure for compound A. Based on the Stille coupling reaction, determine the structure of A by combining the organic halide and the organotin compound. Ensure the product has the correct connectivity and stereochemistry.
Step 3: Analyze the tautomerization of A to B in a basic solution. Tautomerization typically involves the migration of a proton and the shift of a double bond. Propose a mechanism where a base abstracts a proton from A, leading to the formation of an enolate intermediate, which then rearranges to form compound B.
Step 4: Propose a structure for compound B. Based on the tautomerization mechanism, determine the structure of B. Ensure that the structure reflects the rearrangement of bonds and the new protonation state.
Step 5: Suggest a mechanism for the spontaneous conversion of B to C. Analyze the structure of B and propose a plausible reaction pathway (e.g., intramolecular cyclization, elimination, or rearrangement) that leads to the formation of compound C. Ensure the mechanism is consistent with the chemical properties of B and the stability of C.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Stille Coupling Reaction
The Stille coupling reaction is a cross-coupling reaction that involves the reaction of an organostannane with an organic halide in the presence of a palladium catalyst. This reaction is widely used in organic synthesis to form carbon-carbon bonds, allowing for the construction of complex molecules. Understanding the nature of the reactants and the conditions required for this reaction is crucial for proposing the structure of compound A.
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Stille Reaction
Tautomerization
Tautomerization is a chemical reaction that involves the interconversion of two isomers, typically involving the relocation of a proton and a shift of a double bond. In the context of the question, the product of the Stille reaction (compound A) undergoes tautomerization in a basic solution to form compound B. Recognizing the structural changes that occur during tautomerization is essential for understanding how to propose the correct structure for A.
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Mechanism of Organic Reactions
The mechanism of an organic reaction describes the step-by-step process by which reactants are converted into products, detailing the breaking and forming of bonds. For the conversion of compound A to B, it is important to outline the specific steps involved, including any intermediates and transition states. A clear understanding of reaction mechanisms is vital for accurately suggesting how A transforms into B.
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Related Practice
Textbook Question
The product of the Stille coupling reaction (A) tautomerizes in a basic solution to give compound B. B spontaneously converts to C.
(c) Suggest a mechanism for the conversion of B to C
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Textbook Question
In Chapter 20, we studied the aldol reaction. Although not discussed at the time, this reaction is stereospecific, proceeding through the Zimmerman–Traxler transition state shown here.
(a) Show an arrow-pushing mechanism for this concerted reaction.
(b) Why is this a favorable mechanism?
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Textbook Question
While not covered explicitly in this chapter, the ene reaction occurs similarly to the Diels–Alder reaction but replaces the electrons from one bond in the diene with the electrons in a C―H bond. Draw the mechanism for the following reaction. [Number the carbons and draw in the hydrogens of the product. And, of course, make a note of bonds formed and bonds broken.]
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