Textbook Question
Answer Problem 39, parts a–h, using 2-butyne as the starting material instead of propyne.
a. HBr (1 mol)
b. HBr (2 mol)
3
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Ch. 7 - The Reactions of Alkynes • An Introduction to Multistep Synthesis
Bruice8th EditionOrganic ChemistryISBN: 9780135213711
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Table of contents
- Ch. 1 - Remembering General Chemistry: Electronic Structure and Bonding (Part 1)31
- Ch. 1 - Remembering General Chemistry: Electronic Structure and Bonding (Part 2)65
- 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. 7 - The Reactions of Alkynes • An Introduction to Multistep SynthesisProblem 40e
Bruice 8th EditionCh. 7 - The Reactions of Alkynes • An Introduction to Multistep SynthesisProblem 40eChapter 8, Problem 40e
Answer Problem 39, parts a–h, using 2-butyne as the starting material instead of propyne.
e. aqueous H2SO4, HgSO4
Verified step by step guidance1
Identify the starting material: The starting material is 2-butyne, which is an alkyne with the structure CH3-C≡C-CH3.
Understand the reaction conditions: The reagents are aqueous H2SO4 (sulfuric acid) and HgSO4 (mercuric sulfate). This combination is used to catalyze the hydration of alkynes, leading to the formation of a ketone via Markovnikov addition of water.
Determine the mechanism: The reaction proceeds through the formation of an enol intermediate (a compound with a hydroxyl group attached to a carbon-carbon double bond). This enol undergoes tautomerization to form a ketone, which is the more stable product.
Apply Markovnikov's rule: In the hydration of 2-butyne, the OH group from water will add to the more substituted carbon of the triple bond, while the hydrogen will add to the less substituted carbon. This ensures the formation of the more stable ketone.
Write the product structure: The final product will be a ketone, specifically 2-butanone (CH3-CO-CH2-CH3), as the triple bond in 2-butyne is converted into a carbonyl group at the more substituted carbon.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Hydration of Alkynes
The hydration of alkynes involves the addition of water across the triple bond, typically in the presence of an acid catalyst. In this case, 2-butyne reacts with aqueous H2SO4 to form an enol, which subsequently tautomerizes to a ketone. Understanding this process is crucial for predicting the products of the reaction.
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Alkyne Hydration
Markovnikov's Rule
Markovnikov's Rule states that in the addition of HX to an alkene or alkyne, the hydrogen atom will attach to the carbon with the greater number of hydrogen atoms already attached. This principle helps determine the regioselectivity of the hydration reaction, guiding the formation of the more stable carbocation intermediate during the reaction with 2-butyne.
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Tautomerization
Tautomerization is a chemical reaction that involves the rearrangement of bonds within a compound, resulting in the interconversion between two isomers, typically a keto and an enol form. In the context of the hydration of 2-butyne, the initial enol formed from the reaction with H2SO4 will quickly convert to the more stable ketone, which is the final product of the reaction.
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Related Practice
Textbook Question
Answer Problem 39 , parts a–h, using 2-butyne as the starting material instead of propyne.
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1
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Textbook Question
Answer Problem 39, parts a–h, using 2-butyne as the starting material instead of propyne.
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1
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2
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2
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2
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