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−
1179
views
Ch. 9 - Substitution and Elimination Reactions of Alkyl Halides
Bruice8th EditionOrganic ChemistryISBN: 9780135213711
Not the one you use?Change textbookSelect a different textbook
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
All textbooks
Bruice 8th EditionCh. 9 - Substitution and Elimination Reactions of Alkyl HalidesProblem 115a
Bruice 8th EditionCh. 9 - Substitution and Elimination Reactions of Alkyl HalidesProblem 115aChapter 10, Problem 115a
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−
Verified step by step guidance1
Step 1: Identify the reaction type. The problem specifies SN2/E2 reactions. SN2 (bimolecular nucleophilic substitution) involves a backside attack by the nucleophile, leading to inversion of configuration at the carbon center. E2 (bimolecular elimination) involves the removal of a proton and a leaving group, forming a double bond.
Step 2: Analyze the substrate. The substrate is (3S,4S)-3-bromo-4-methylhexane. The bromine atom is the leaving group, and the stereochemistry at carbon-3 is S. Carbon-4 has a methyl group and is also stereogenic with S configuration.
Step 3: 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 (e.g., solvent, temperature) will influence which pathway dominates, but both products should be considered.
Step 4: For the SN2 pathway, the methoxide ion will attack the carbon-3 (where the bromine is attached) from the opposite side of the leaving group. This backside attack will result in inversion of configuration at carbon-3, changing it from S to R. The product will retain the stereochemistry at carbon-4 (S).
Step 5: For the E2 pathway, the methoxide ion will abstract a β-hydrogen (a hydrogen on a carbon adjacent to the carbon bearing the leaving group). The most likely β-hydrogen to be removed is on carbon-2, leading to the formation of a double bond between carbon-2 and carbon-3. The stereochemistry of the double bond will depend on the anti-periplanar arrangement of the β-hydrogen and the leaving group during the elimination process.
Verified video answer for a similar problem:
This video solution was recommended by our tutors as helpful for the problem above.
Video duration:
4mWas this helpful?
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 is a one-step mechanism where a nucleophile attacks an electrophile, resulting in the simultaneous displacement of a leaving group. This reaction is characterized by a backside attack, leading to inversion of configuration at the carbon center. The rate of the reaction depends on the concentration of both the nucleophile and the substrate.
Recommended video:
Guided course
08:33
Drawing the SN2 Mechanism
E2 Reaction Mechanism
The E2 (elimination bimolecular) reaction is a concerted mechanism where a base abstracts a proton while a leaving group departs, resulting in the formation of a double bond. This reaction typically requires a strong base and occurs in a single step, leading to the formation of alkenes. The stereochemistry of the reactants can influence the product's geometry, often favoring the formation of the more stable trans isomer.
Recommended video:
Guided course
09:36Drawing the E2 Mechanism.
Stereoisomerism
Stereoisomerism refers to the phenomenon where compounds have the same molecular formula and connectivity but differ in the spatial arrangement of atoms. In the context of SN2 and E2 reactions, stereoisomers can arise from the different orientations of substituents around a chiral center or double bond. Understanding stereoisomerism is crucial for predicting the specific products formed in these reactions, including their potential enantiomers and diastereomers.
Recommended video:
Guided course
01:58Determining when molecules are stereoisomers.
Related Practice
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.
1671
views
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.
975
views
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?
1678
views
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.
b. (3R,4R)-3-bromo-4-methylhexane + CH3O−
927
views
Textbook Question
Draw the elimination products for each of the following E2 reactions; if the products can exist as stereoisomers, indicate which stereoisomers are obtained.
e. 3-chloro-3-ethyl-2,2-dimethylpentane + high concentration of CH3CH2O-
872
views