Textbook Question
What substitution products are obtained when each of the following compounds is added to a solution of sodium acetate in acetic acid?
a. 2-chloro-2-methyl-3-hexene
b. 3-bromo-1-methylcyclohexene
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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 103a,b
Bruice 8th EditionCh. 9 - Substitution and Elimination Reactions of Alkyl HalidesProblem 103a,bChapter 10, Problem 103a,b
Draw the substitution and elimination products.
a. 
b. 
Verified step by step guidance1
Step 1: Analyze the reactants and conditions. The substrate in both cases is a brominated alkane, and the reagent is methoxide ion (CH₃O⁻), which is a strong base and a good nucleophile. This suggests that both substitution (S_N2) and elimination (E2) reactions are possible.
Step 2: For substitution (S_N2), the methoxide ion will attack the carbon bonded to bromine directly, displacing the bromine atom. This reaction occurs in a single step and is favored for primary alkyl halides (as in part a). The product will be an ether (CH₃O attached to the carbon).
Step 3: For elimination (E2), the methoxide ion will act as a base and abstract a proton from a β-carbon (a carbon adjacent to the carbon bonded to bromine). This leads to the formation of a double bond between the α-carbon (the carbon bonded to bromine) and the β-carbon, with bromine leaving as a leaving group. The product will be an alkene.
Step 4: In part a, the substrate is a primary alkyl halide, so substitution (S_N2) is likely to be the major pathway, but elimination (E2) can also occur under these conditions. The substitution product will be CH₃OCH₂CH₂CH₂CH₃, and the elimination product will be CH₂=CHCH₂CH₃.
Step 5: In part b, the substrate is a secondary alkyl halide, which makes elimination (E2) more favorable due to steric hindrance around the electrophilic carbon. The elimination product will be the more substituted alkene (Zaitsev product), CH₃CH=CHCH₂CH₃, while the substitution product will be CH₃OCH(CH₃)CH₂CH₃.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Nucleophilic Substitution
Nucleophilic substitution is a fundamental reaction in organic chemistry where a nucleophile replaces a leaving group in a molecule. This process can occur via two main mechanisms: SN1, which involves a two-step process with a carbocation intermediate, and SN2, which is a one-step process where the nucleophile attacks the substrate simultaneously as the leaving group departs. Understanding the conditions that favor each mechanism is crucial for predicting the products of substitution reactions.
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Nucleophiles and Electrophiles can react in Substitution Reactions.
Elimination Reactions
Elimination reactions involve the removal of a small molecule, typically water or hydrogen halide, from a larger molecule, resulting in the formation of a double bond. The two primary types are E1, which is a two-step process involving a carbocation intermediate, and E2, which is a concerted mechanism where the base abstracts a proton while the leaving group departs. Recognizing the factors that influence elimination, such as substrate structure and the strength of the base, is essential for determining the products.
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Regioselectivity and Stereochemistry
Regioselectivity refers to the preference of a chemical reaction to yield one structural isomer over others when multiple possibilities exist. In substitution and elimination reactions, the regioselectivity can be influenced by the stability of intermediates and the nature of the nucleophile or base. Stereochemistry, on the other hand, deals with the spatial arrangement of atoms in molecules, which is crucial in determining the configuration of products, especially in reactions involving chiral centers.
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Related Practice
Textbook Question
Show how each of the following compounds can be synthesized from the given starting materials:
a. CH3CH2CH2Br→CH3CH2CH2CH2CH3
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Textbook Question
cis-1-Bromo-4-tert-butylcyclohexane and trans-1-bromo-4-tert-butylcyclohexane both react with sodium ethoxide in ethanol to form 4-tert-butylcyclohexene. Explain why the cis isomer reacts much more rapidly than the trans isomer.
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Textbook Question
tert-Butyl chloride undergoes solvolysis in both acetic acid and formic acid. Solvolysis occurs 5000 times faster in one of these two solvents than in the other. In which solvent is solvolysis faster? Explain your answer. (Hint: Formic acid is more polar than acetic acid.)
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Textbook Question
a. Draw the structures of the products obtained from the reaction of each enantiomer of cis-1-chloro-2-isopropylcyclopentane with sodium methoxide in methanol.
b. Are all the products optically active?
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Textbook Question
When the following compound undergoes solvolysis in ethanol, three products are obtained. Propose a mechanism to account for the formation of these products.
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