Textbook Question
Draw the products of each of the following SN2/E2 reactions. If the products can exist as stereoisomers, show which stereoisomers are formed.
c. (3S,4R)-3-bromo-4-methylhexane + CH3O−
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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 115b
Bruice 8th EditionCh. 9 - Substitution and Elimination Reactions of Alkyl HalidesProblem 115bChapter 10, Problem 115b
Draw the products of each of the following SN2/E2 reactions. If the products can exist as stereoisomers, show which stereoisomers are formed.
b. (3R,4R)-3-bromo-4-methylhexane + CH3O−
Verified step by step guidance1
Identify the type of reaction: The problem specifies SN2/E2 reactions. SN2 reactions involve a backside attack by the nucleophile, leading to inversion of configuration at the carbon center. E2 reactions involve elimination, forming a double bond between adjacent carbons.
Analyze the substrate: The substrate is (3R,4R)-3-bromo-4-methylhexane. The bromine atom is attached to the 3rd carbon, and the 4th carbon has a methyl group. The stereochemistry is specified as (3R,4R), so the 3rd carbon is in the R configuration, and the 4th carbon is also in the R configuration.
Consider the nucleophile/base: CH3O⁻ (methoxide ion) is both a strong nucleophile and a strong base. This means it can participate in both SN2 and E2 mechanisms. The reaction conditions will determine which pathway dominates.
Determine the products for each mechanism: For the SN2 reaction, the methoxide ion will attack the 3rd carbon (where the bromine is attached) from the opposite side, displacing the bromine and inverting the configuration at the 3rd carbon. For the E2 reaction, the methoxide ion will abstract a β-hydrogen (from the 2nd or 4th carbon), leading to the formation of a double bond between the 2nd and 3rd carbons or the 3rd and 4th carbons. Consider Zaitsev's rule, which favors the more substituted alkene.
Account for stereoisomers: For the SN2 product, the inversion of configuration at the 3rd carbon will result in a specific stereoisomer. For the E2 product, if a double bond forms between the 3rd and 4th carbons, cis/trans (E/Z) isomerism may occur. Draw all possible stereoisomers for the products and label them clearly.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
SN2 Reaction Mechanism
The SN2 (substitution nucleophilic bimolecular) reaction involves a nucleophile attacking an electrophile, resulting in the simultaneous displacement of a leaving group. This mechanism is characterized by a single concerted step, where the nucleophile approaches the electrophile from the opposite side of the leaving group, leading to inversion of configuration at the chiral center. Understanding this mechanism is crucial for predicting the stereochemical outcome of reactions.
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Drawing the SN2 Mechanism
E2 Reaction Mechanism
The E2 (elimination bimolecular) reaction is a one-step process where a base abstracts a proton from a β-carbon while a leaving group departs from the α-carbon, resulting in the formation of a double bond. This reaction typically requires a strong base and is stereospecific, often favoring the formation of the more stable alkene. Recognizing the conditions that favor E2 over SN2 is essential for determining the products of the reaction.
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09:36Drawing the E2 Mechanism.
Stereoisomerism
Stereoisomerism refers to the existence of compounds with the same molecular formula and connectivity but different spatial arrangements of atoms. In the context of the given reaction, the formation of stereoisomers can occur due to the chiral centers present in the substrate. Understanding how stereochemistry is affected by the reaction mechanism (SN2 or E2) is vital for accurately depicting the products and their stereoisomers.
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01:58Determining when molecules are stereoisomers.
Related Practice
Textbook Question
Draw the structures of the products obtained from the following reaction:
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Textbook Question
Draw the major elimination product that would be obtained from each of the following reactants with a strong base and with a weak base:
a.
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Textbook Question
Explain why the rate of the reaction of 1-bromo-2-butene with ethanol is increased if silver nitrate is added to the reaction mixture.
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Textbook Question
Draw the products of each of the following SN2/E2 reactions. If the products can exist as stereoisomers, show which stereoisomers are formed.
a. (3S,4S)-3-bromo-4-methylhexane + CH3O−
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Textbook Question
Two elimination products are obtained from the following E2 reaction:
a. What are the elimination products?
b. Which is formed in greater yield?
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