Textbook Question
Show how you might use SN2 reactions to convert 1-chlorobutane into the following compounds.
c. 1-iodobutane
d. CH3—(CH2)3—CN
2004
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Ch.6 - Alkyl Halides; Nucleophilic Substitution
Wade9th EditionOrganic ChemistryISBN: 9780135213728
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Table of contents
- Ch.1 - Structure and Bonding107
- Ch. 2 - Acids and Bases; Functional Groups115
- Ch.3 - Structure and Stereochemistry of Alkanes100
- Ch.4 - The Study of Chemical Reactions99
- Ch.5 - Stereochemistry93
- Ch.6 - Alkyl Halides; Nucleophilic Substitution118
- Ch. 7 - Structure and Synthesis of Alkenes; Elimination158
- Ch.8 - Reactions of Alkenes171
- Ch.9 - Alkynes91
- Ch.10 - Structure and Synthesis of Alcohols143
- Ch.11 - Reactions of Alcohols104
- Ch. 12 - Infrared Spectroscopy and Mass Spectrometry22
- Ch. 13 - Nuclear Magnetic Resonance Spectroscopy45
- Ch. 14 - Ethers, Epoxides, and Thioethers72
- Ch. 15 - Conjugated Systems, Orbital Symmetry, and Ultraviolet Spectroscopy89
- Ch. 16 - Aromatic Compounds74
- Ch. 17 - Reactions of Aromatic Compounds126
- Ch. 18 - Ketones and Aldehydes193
- Ch. 19 - Amines129
- Ch. 20 - Carboxylic Acids77
- Ch. 21 - Carboxylic Acid Derivatives141
- Ch. 22 - Condensations and Alpha Substitutions of Carbonyl Compounds175
- Ch. 23 - Carbohydrates and Nucleic Acids93
- Ch. 24 - Amino Acids, Peptides, and Proteins54
Chapter 6, Problem 14f
Predict the major products of the following substitutions.
f. 
Verified step by step guidance1
Identify the type of substitution reaction: The presence of KF (potassium fluoride) and 18-crown-6 suggests that this is a nucleophilic substitution reaction. The 18-crown-6 ether acts as a phase-transfer catalyst, solubilizing the potassium ion and leaving fluoride (F⁻) as a free nucleophile in the organic solvent (CH₃CN).
Analyze the substrate: 1-chloropentane is a primary alkyl halide. Primary alkyl halides typically undergo SN2 (bimolecular nucleophilic substitution) reactions because the steric hindrance around the carbon attached to the leaving group is minimal.
Determine the nucleophile and leaving group: The nucleophile is fluoride (F⁻), and the leaving group is chloride (Cl⁻). In an SN2 reaction, the nucleophile attacks the carbon attached to the leaving group from the opposite side, leading to an inversion of configuration at the carbon center.
Write the reaction mechanism: The fluoride ion (F⁻) attacks the carbon bonded to the chlorine atom in a single concerted step, displacing the chloride ion (Cl⁻) and forming a new C-F bond. This results in the substitution of the chlorine atom with a fluorine atom.
Predict the major product: The major product of this reaction will be 1-fluoropentane, as the fluoride ion replaces the chlorine atom in the primary alkyl halide through the SN2 mechanism.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Nucleophilic Substitution Reactions
Nucleophilic substitution reactions involve the replacement of a leaving group in a molecule with a nucleophile. In this context, 1-chloropentane serves as the substrate, where the chlorine atom is the leaving group. Understanding the mechanism (either SN1 or SN2) is crucial for predicting the products, as it influences the reaction pathway and the stereochemistry of the resulting compounds.
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Nucleophiles and Electrophiles can react in Substitution Reactions.
Crown Ethers
Crown ethers, such as 18-crown-6, are cyclic compounds that can selectively bind cations, enhancing the solubility of ionic species in nonpolar solvents. In this reaction, 18-crown-6 facilitates the nucleophilicity of the fluoride ion (from KF) by stabilizing it in the solvent (CH3CN), which can lead to a more favorable substitution reaction with 1-chloropentane.
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04:22How to predict the products of Ether Cleavage.
Solvent Effects on Reaction Mechanisms
The choice of solvent can significantly influence the mechanism and outcome of nucleophilic substitution reactions. In this case, CH3CN (acetonitrile) is a polar aprotic solvent that enhances the nucleophilicity of fluoride ions, promoting an SN2 mechanism. Understanding how solvents affect reaction rates and mechanisms is essential for predicting the major products of the reaction.
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02:26General format of reactions and how to interpret solvents.
Related Practice
Textbook Question
When methylenecyclohexane is treated with a low concentration of bromine under irradiation by a sunlamp, two substitution products are formed.
a. Propose structures for these two products. (b) Propose a mechanism to account for their formation.
1847
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Textbook Question
Predict the major products of the following substitutions.
b.
1849
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Textbook Question
Show how you might use SN2 reactions to convert 1-chlorobutane into the following compounds.
e. CH3—(CH2)3—C≡CH
f. CH3CH2—O—(CH2)3—CH3
g. CH3—(CH2)3—NH2
1766
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Textbook Question
Predict the major products of the following substitutions.
e. 1-chloropentane + NaI →
1849
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Textbook Question
Predict the major products of the following substitutions.
d. CH3CH2CH2I + NaCN →
2005
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