Textbook Question
What products will be obtained from the E2 reaction of the following alkyl halides?
a.
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Ch. 9 - Substitution and Elimination Reactions of Alkyl Halides
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. 9 - Substitution and Elimination Reactions of Alkyl HalidesProblem 43a,b
Bruice 8th EditionCh. 9 - Substitution and Elimination Reactions of Alkyl HalidesProblem 43a,bChapter 10, Problem 43a,b
a. Explain why 1-bromo-2,2-dimethylpropane has difficulty undergoing both SN2 and SN1 reactions.
b. Can it undergo E2 and E1 reactions?
Verified step by step guidance1
Step 1: Analyze the structure of 1-bromo-2,2-dimethylpropane. The molecule has a tertiary carbon bonded to the bromine atom, surrounded by bulky methyl groups. This steric hindrance plays a key role in its reactivity.
Step 2: Explain the difficulty in undergoing SN2 reactions. SN2 reactions require a backside attack by the nucleophile, which is hindered by the bulky methyl groups surrounding the tertiary carbon. This steric hindrance prevents the nucleophile from accessing the electrophilic carbon effectively.
Step 3: Explain the difficulty in undergoing SN1 reactions. SN1 reactions proceed via the formation of a carbocation intermediate. While the tertiary carbon can stabilize a carbocation due to hyperconjugation and inductive effects, the bulky groups around the carbon create steric strain, making the carbocation formation less favorable.
Step 4: Discuss the possibility of E2 reactions. E2 reactions require a strong base and a β-hydrogen to be eliminated. The bulky groups around the tertiary carbon do not prevent the elimination mechanism, so E2 reactions are possible under appropriate conditions.
Step 5: Discuss the possibility of E1 reactions. E1 reactions proceed via carbocation formation, similar to SN1. Since the tertiary carbon can stabilize a carbocation, E1 reactions are possible, especially under acidic conditions or with a weak base.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
SN2 Reactions
SN2 (Substitution Nucleophilic Bimolecular) reactions involve a single concerted step where a nucleophile attacks the electrophilic carbon, displacing a leaving group. The reaction rate depends on the concentration of both the nucleophile and the substrate. Steric hindrance around the electrophilic carbon can significantly hinder SN2 reactions, making tertiary substrates like 1-bromo-2,2-dimethylpropane less favorable for this mechanism.
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Understanding the properties of SN2.
SN1 Reactions
SN1 (Substitution Nucleophilic Unimolecular) reactions proceed through a two-step mechanism where the leaving group departs first, forming a carbocation intermediate, followed by nucleophilic attack. The stability of the carbocation is crucial; tertiary carbocations are more stable than secondary or primary ones. However, 1-bromo-2,2-dimethylpropane's steric hindrance can lead to a less stable carbocation, making SN1 reactions less favorable.
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08:16Understanding the properties of SN1.
E2 and E1 Reactions
E2 (Elimination Bimolecular) and E1 (Elimination Unimolecular) reactions involve the removal of a leaving group and a hydrogen atom to form a double bond. E2 reactions require a strong base and occur in a single concerted step, while E1 reactions involve a carbocation intermediate. The bulky structure of 1-bromo-2,2-dimethylpropane may favor E2 reactions due to steric hindrance, while E1 reactions may also occur if a stable carbocation can be formed.
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03:32Understanding the properties of E1.
Related Practice
Textbook Question
You were told in [SECTION 7.11] that is best to use a methyl halide or a primary alkyl halide for the reaction of an acetylide ion with an alkyl halide. Explain why this is so.
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Textbook Question
What products will be obtained from the E2 reaction of the following alkyl halides?
b.
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Textbook Question
Explain why only a substitution product and no elimination product is obtained when the following compound reacts with sodium methoxide:
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Textbook Question
a. Assuming that the two compounds shown below have the same stability, which one would you expect to be more reactive in an SN1 reaction?
b. Draw the products that each would form when the solvent is ethanol.
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Textbook Question
How does the ratio of substitution product to elimination product formed from the reaction of propyl bromide with CH3O− in methanol change if the nucleophile is changed to CH3S−?
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