Textbook Question
Each of the following reactions has two nucleophiles that could add to the intermediate formed by the reaction of the alkene with an electrophile. What is the major product of each reaction?
c.
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Ch. 6 - The Reactions of Alkenes • The Stereochemistry of Addition Reactions
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. 6 - The Reactions of Alkenes • The Stereochemistry of Addition ReactionsProblem 25a,b
Bruice 8th EditionCh. 6 - The Reactions of Alkenes • The Stereochemistry of Addition ReactionsProblem 25a,bChapter 7, Problem 25a,b
What will be the major product obtained from the reaction of Br2 with 1-butene if the reaction is carried out in
a. dichloromethane?
b. water?
Verified step by step guidance1
Identify the type of reaction occurring in each case. For part (a), the reaction of Br2 with 1-butene in dichloromethane is an electrophilic addition reaction in a non-polar solvent. For part (b), the reaction of Br2 with 1-butene in water involves a bromohydrin formation due to the presence of a polar protic solvent.
For part (a), in the presence of dichloromethane, the Br2 molecule acts as an electrophile. The π-electrons of the double bond in 1-butene attack the Br2 molecule, forming a cyclic bromonium ion intermediate.
Still in part (a), the bromonium ion is then attacked by a bromide ion (Br⁻) from the back side, leading to the anti-addition of bromine across the double bond. This results in the formation of 2,3-dibromobutane as the major product.
For part (b), in the presence of water, the reaction mechanism begins similarly with the formation of a bromonium ion intermediate. However, instead of a bromide ion attacking the intermediate, a water molecule (H2O) acts as the nucleophile due to its abundance in the reaction medium.
In part (b), the water molecule attacks the more substituted carbon of the bromonium ion (Markovnikov addition), leading to the formation of a bromohydrin. After deprotonation of the attached water molecule, the major product is 2-bromo-1-butanol.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Electrophilic Addition
Electrophilic addition is a fundamental reaction mechanism in organic chemistry where an electrophile reacts with a nucleophile, typically involving alkenes. In the case of 1-butene reacting with Br2, the double bond acts as a nucleophile, attacking the bromine molecule, leading to the formation of a bromonium ion intermediate. This process is crucial for understanding how alkenes react with halogens.
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Solvent Effects on Reaction Mechanisms
The choice of solvent can significantly influence the outcome of a chemical reaction. In non-polar solvents like dichloromethane, the reaction may favor the formation of a more stable product through a direct addition mechanism. Conversely, in polar solvents like water, the reaction can lead to different products due to the solvent's ability to stabilize charged intermediates, affecting the regioselectivity and stereochemistry of the final product.
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Regioselectivity
Regioselectivity refers to the preference of a chemical reaction to yield one structural isomer over others when multiple possibilities exist. In the reaction of Br2 with 1-butene, the regioselectivity will depend on the solvent and the stability of the intermediates formed. For example, in water, the formation of a bromohydrin may occur, while in dichloromethane, a dibromide may be the major product, illustrating how regioselectivity is influenced by reaction conditions.
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Related Practice
Textbook Question
What is the product of the addition of I—Cl to 1-butene? (Hint: Chlorine is more electronegative than iodine [Table 1.3].)
1369
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Textbook Question
Draw structures for the following:
a. 2-propyloxirane
b. cyclohexene oxide
1112
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Textbook Question
What will be the major product obtained from the reaction of Br2 with 1-butene if the reaction is carried out in
c. ethyl alcohol?
d. methyl alcohol?
1491
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Textbook Question
Each of the following reactions has two nucleophiles that could add to the intermediate formed by the reaction of the alkene with an electrophile. What is the major product of each reaction?
b.
1726
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Textbook Question
Draw structures for the following:
c. 2,2,3,3-tetramethyloxirane
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