Textbook Question
What hydrocarbon with the same molecular formula as in part a forms three monochlorinated products? One is achiral and two are chiral.
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Ch. 12 - Radicals
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
Chapter 13, Problem 14c,d
What is the major product of the reaction of 2-methyl-2-butene with each of the following reagents?
c. HBr + peroxide
d. HCl + peroxide
Verified step by step guidance1
Identify the type of reaction: The reaction involves an alkene (2-methyl-2-butene) reacting with hydrogen halides (HBr and HCl) in the presence of peroxides. The presence of peroxides indicates that the reaction will proceed via a free radical mechanism, specifically the anti-Markovnikov addition of the halogen.
Understand the anti-Markovnikov rule: In the presence of peroxides, the addition of HBr to an alkene follows the anti-Markovnikov rule. This means the bromine atom will add to the less substituted carbon of the double bond, while the hydrogen atom will add to the more substituted carbon. This occurs due to the formation of a bromine radical during the reaction.
Analyze the reaction with HBr + peroxide: For 2-methyl-2-butene, the double bond is between the second and third carbons. The less substituted carbon is the terminal carbon (C1), so the bromine atom will attach to C1, and the hydrogen atom will attach to the more substituted carbon (C2). This results in the formation of the anti-Markovnikov product.
Analyze the reaction with HCl + peroxide: Unlike HBr, HCl does not undergo a free radical mechanism in the presence of peroxides. This is because the bond dissociation energy of HCl is higher than that of HBr, making it less favorable to form a chlorine radical. Therefore, the reaction will proceed via the standard Markovnikov addition mechanism, where the hydrogen atom adds to the less substituted carbon (C1), and the chlorine atom adds to the more substituted carbon (C2).
Summarize the products: For HBr + peroxide, the major product is the anti-Markovnikov addition product, where bromine is attached to the less substituted carbon. For HCl + peroxide, the major product is the Markovnikov addition product, where chlorine is attached to 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.
Markovnikov's Rule
Markovnikov's Rule states that in the addition of HX to an alkene, the hydrogen atom (H) will attach to the carbon with the greater number of hydrogen atoms already attached, while the halide (X) will attach to the carbon with fewer hydrogen atoms. This rule helps predict the major product of electrophilic addition reactions involving alkenes.
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The 18 and 16 Electron Rule
Anti-Markovnikov Addition
Anti-Markovnikov addition occurs when the addition of HX to an alkene results in the halide attaching to the more substituted carbon, contrary to Markovnikov's Rule. This is often facilitated by the presence of peroxides, which lead to the formation of free radicals and favor the formation of the less stable radical intermediate.
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02:43Anti-Markovnikov addition of alcohols to terminal alkynes yields aldehydes
Free Radical Mechanism
The free radical mechanism involves the formation of free radicals during a chemical reaction, which are highly reactive species with unpaired electrons. In the context of alkene reactions with HBr or HCl in the presence of peroxides, this mechanism leads to the anti-Markovnikov product due to the stability of the radical intermediates formed during the reaction.
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03:28The mechanism of Radical Polymerization.
Related Practice
Textbook Question
Which ether is least apt to form a peroxide?
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Textbook Question
Which ether is most apt to form a peroxide?
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Textbook Question
Two products are formed when methylenecyclohexane reacts with NBS? Show how each is formed. Disregard stereoisomers.
1673
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Textbook Question
Write the propagation steps for the addition of HBr to 1-methylcyclohexene in the presence of a peroxide
1446
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Textbook Question
What hydrocarbon with molecular formula C4H10 forms only two monochlorinated products? Both products are achiral.
1576
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