Textbook Question
For each compound, give the product(s) expected from (1) HgSO4/H2SO4 - catalyzed hydration and (2) hydroboration–oxidation.
d. cyclodecyne
Ch.9 - Alkynes
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 9, Problem 23a
Predict the product(s) you would expect from treatment of each compound with (1) dilute, neutral KMnO4 and (2) warm basic KMnO4, then dilute acid.
(a) hex-1-yne
Verified step by step guidance1
Step 1: Understand the reactivity of KMnO4 with alkynes. Neutral, dilute KMnO4 typically performs mild oxidation, while warm, basic KMnO4 followed by acid treatment leads to oxidative cleavage of the triple bond.
Step 2: For reaction with dilute, neutral KMnO4, recognize that hex-1-yne will undergo mild oxidation. The triple bond will be converted into a diol (a compound with two hydroxyl groups) at the site of the triple bond.
Step 3: For reaction with warm, basic KMnO4 followed by acid treatment, understand that the triple bond in hex-1-yne will be cleaved completely. Each carbon of the triple bond will be oxidized to form carboxylic acids.
Step 4: Identify the structure of hex-1-yne. It is a six-carbon alkyne with the triple bond located between the first and second carbons. For oxidative cleavage, the products will depend on the position of the triple bond.
Step 5: Predict the products. For dilute KMnO4, the product will be a diol at the triple bond site. For warm, basic KMnO4 followed by acid, the triple bond will cleave, yielding acetic acid (CH₃COOH) and pentanoic acid (C₄H₉COOH).
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Alkyne Reactivity
Alkynes, characterized by a carbon-carbon triple bond, undergo various reactions due to their high reactivity. They can participate in addition reactions, where reagents add across the triple bond, and oxidation reactions, which can lead to the formation of carbonyl compounds or carboxylic acids depending on the conditions.
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09:11
Alkyne Hydration
Oxidation with KMnO4
Potassium permanganate (KMnO4) is a strong oxidizing agent used in organic chemistry. In dilute, neutral conditions, it typically oxidizes alkynes to form cis-diol products, while in warm basic conditions followed by acid treatment, it can cleave the triple bond, resulting in carboxylic acids or ketones, depending on the structure of the alkyne.
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03:20Benzylic Oxidation
Mechanism of Oxidation
The mechanism of oxidation with KMnO4 involves the formation of a cyclic manganate ester intermediate, which subsequently leads to the addition of hydroxyl groups across the double bond. Understanding this mechanism is crucial for predicting the products of the reaction, as it dictates the stereochemistry and the nature of the final products formed from the alkyne.
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01:31Oxidative Workup Mechanism:
Related Practice
Textbook Question
Disiamylborane adds only once to alkynes by virtue of its two bulky secondary isoamyl groups. Disiamylborane is prepared by the reaction of BH3·THF with an alkene.
a. Draw the structural formulas of the reagents and the products in the preparation of disiamylborane.
b. Explain why the reaction in part (a) goes only as far as the dialkylborane. Why is Sia3B not formed?
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Textbook Question
For each compound, give the product(s) expected from (1) HgSO4/H2SO4 - catalyzed hydration and (2) hydroboration–oxidation.
c. hex-3-yne
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Textbook Question
Predict the product(s) you would expect from treatment of each compound with (1) dilute, neutral KMnO4 and (2) warm basic KMnO4, then dilute acid.
(d) 2-methylhex-3-yne
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Textbook Question
Predict the product(s) you would expect from treatment of each compound with (1) dilute, neutral KMnO4 and (2) warm basic KMnO4, then dilute acid.
(b) hex-2-yne
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Textbook Question
Predict the product(s) you would expect from treatment of each compound with (1) dilute, neutral KMnO4 and (2) warm basic KMnO4, then dilute acid.
(c) hex-3-yne
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