Textbook Question
Propose a mechanism for reaction of the first three propylene units in the polymerization of propylene in the presence of a peroxide.
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Ch.8 - Reactions of Alkenes
Wade9th EditionOrganic ChemistryISBN: 9780135213728
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Table of contents
- 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
Chapter 8, Problem 70a
The following cyclization has been observed in the oxymercuration-demercuration of this unsaturated alcohol. Propose a mechanism for this reaction.
Verified step by step guidance1
Step 1: Analyze the reaction conditions. The reaction involves oxymercuration–demercuration, which typically proceeds via the addition of mercuric acetate (Hg(OAc)₂) to an alkene, followed by reduction with sodium borohydride (NaBH₄). This reaction is known for Markovnikov addition of water across the double bond without carbocation rearrangement.
Step 2: Identify the starting material and product. The starting material is an unsaturated alcohol with a hydroxyl group (-OH) and a double bond. The product is a cyclic ether, indicating that cyclization has occurred during the reaction.
Step 3: Propose the mechanism for oxymercuration. The double bond in the starting material reacts with Hg(OAc)₂ to form a mercurinium ion intermediate. This intermediate is stabilized by the hydroxyl group, which can act as a nucleophile and attack the more substituted carbon of the mercurinium ion, leading to ring closure.
Step 4: Explain the demercuration step. After cyclization, the organomercury intermediate is reduced by NaBH₄, which replaces the mercury group with a hydrogen atom, yielding the final cyclic ether product.
Step 5: Highlight the stereochemical and regiochemical outcomes. The reaction proceeds with Markovnikov regioselectivity, and the hydroxyl group facilitates intramolecular nucleophilic attack, leading to the formation of the cyclic ether. The stereochemistry of the product depends on the specific geometry of the starting material and the reaction pathway.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Oxymercuration-Demercuration
Oxymercuration-demercuration is a two-step reaction used to convert alkenes into alcohols. The first step involves the addition of mercuric acetate (Hg(OAc)2) to the alkene, forming a mercurinium ion intermediate. This intermediate is then attacked by water, leading to the formation of an alcohol. The second step, demercuration, involves the reduction of the mercurial compound to yield the final alcohol product.
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General properties of oxymercuration-reduction.
Mechanism of Cyclization
Cyclization refers to the process where a linear or branched chain molecule forms a cyclic structure. In the context of the oxymercuration-demercuration reaction, the formation of a cyclic ether or alcohol can occur through intramolecular nucleophilic attack. Understanding the mechanism of cyclization is crucial for predicting the product structure and the stereochemistry of the reaction.
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Stereochemistry
Stereochemistry is the study of the spatial arrangement of atoms in molecules and how this affects their chemical behavior. In reactions involving cyclic compounds, stereochemistry plays a significant role in determining the configuration of the product. It is essential to consider stereochemical outcomes when proposing mechanisms, especially in reactions that involve chiral centers or multiple stereogenic centers.
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Related Practice
Textbook Question
An unknown compound decolorizes bromine in carbon tetrachloride, and it undergoes catalytic reduction to give decalin. When treated with warm, concentrated potassium permanganate, this compound gives cis-cyclohexane-1,2-dicarboxylic acid and oxalic acid. Propose a structure for the unknown compound.
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Textbook Question
Predict the product of formula C7H13BrO from the reaction of this same unsaturated alcohol with bromine. Propose a mechanism to support your prediction.
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Textbook Question
The two butenedioic acids are called fumaric acid (trans) and maleic acid (cis). 2,3-Dihydroxybutanedioic acid is called tartaric acid.
Show how you would convert
c. maleic acid to (±)-tartaric acid.
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Textbook Question
The two butenedioic acids are called fumaric acid (trans) and maleic acid (cis). 2,3-Dihydroxybutanedioic acid is called tartaric acid.
Show how you would convert
b. fumaric acid to meso-tartaric acid.
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Textbook Question
A graduate student attempted to form the iodohydrin of the alkene shown below. Her analysis of the products showed a good yield of an unexpected product. Propose a mechanism to explain the formation of this product.
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