Textbook Question
Show a mechanism for the following elimination reactions. Label the mechanism as E1 or E2.
(c)
2
views
Ch. 12 - Substitution and Elimination: Reactions of Haloalkanes
Mullins1st EditionOrganic Chemistry: A Learner Centered ApproachISBN: 9780137566471
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Table of contents
- Ch. 2 - General Chemistry Translated: Finding the Electrons114
- Ch. 3 - Alkanes and Cycloalkanes: Properties and Conformational Analysis109
- Ch. 4 - Acids and Bases: Electron Flow144
- Ch. 5 - Chemical Reaction Analysis: Thermodynamics and Kinetics118
- Ch. 6 - Stereoisomerism: Arrangement of Atoms in Space112
- Ch. 7 - Principles of Green (Organic) Chemistry3
- Ch. 8 - Alkenes I: Properties and Electrophilic Additions158
- Ch. 9 - Alkenes II: Oxidation and Reduction150
- Ch. 10 - Alkynes: Electrophilic Addition and Redox Reactions101
- Ch. 11 - Properties and Synthesis of Alkyl Halides: Radical Reactions108
- Ch. 12 - Substitution and Elimination: Reactions of Haloalkanes172
- Ch. 13 - Alcohols, Ethers and Related Compounds: Substitution and Elimination239
- Ch. 14 - Structural Identification I: Infrared Spectroscopy and Mass Spectrometry54
- Ch. 15 - Structural Identification II: Nuclear Magnetic Resonance Spectroscopy93
- Ch. 16 - Metals in Organic Chemistry48
- Ch. 17 - Carbonyl Addition Reactions: Aldehydes and Ketones45
- Ch. 18 - Nucleophilic Acyl Substitution I: Carboxylic Acids18
- Ch. 19 - Nucleophilic Acyl Substitution II: Carboxylic Acid Derivatives39
- Ch. 20 - Enolates: Carbonyl Addition and Substitution13
- Ch. 21 - Conjugated Systems I: Stability and Addition Reactions56
- Ch. 22 - Conjugated Systems II: Pericyclic Reactions54
- Ch. 23 - Benzene I: Aromatic Stability and Substitution Reactions64
- Ch. 24 - Benzene II: Reactions Influenced by the Aromatic Ring62
- Ch. 25 - Amines: Structure, Reactions, and Synthesis27
- Ch. 26 - Amino Acids, Proteins, and Peptide Synthesis9
- Ch. 27 - Carbohydrates, Nucleic Acids, and Lipids54
Mullins1st EditionOrganic Chemistry: A Learner Centered ApproachISBN: 9780137566471Not the one you use?Change textbook
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Mullins 1st EditionCh. 12 - Substitution and Elimination: Reactions of HaloalkanesProblem 43a
Mullins 1st EditionCh. 12 - Substitution and Elimination: Reactions of HaloalkanesProblem 43aChapter 11, Problem 43a
Suggest an appropriate base to synthesize the alkene as the major product from the starting haloalkane.
(a) 
Verified step by step guidance1
Step 1: Understand the reaction type. The synthesis of an alkene from a haloalkane typically involves an elimination reaction (E2 or E1 mechanism). The choice of base is crucial for favoring the elimination pathway over substitution.
Step 2: Analyze the structure of the haloalkane. Determine whether the haloalkane is primary, secondary, or tertiary. This will influence the mechanism (E2 or E1) and the strength of the base required.
Step 3: Consider steric hindrance. If the haloalkane is bulky (e.g., tertiary), a strong, bulky base like potassium tert-butoxide (K⁺[CH₃]₃CO⁻) is often used to favor elimination and minimize substitution.
Step 4: Evaluate the reaction conditions. Strong bases such as sodium hydroxide (NaOH) or potassium hydroxide (KOH) can be used for E2 elimination, while weaker bases may favor E1 elimination under acidic conditions.
Step 5: Select the base based on regioselectivity. If the goal is to form the more substituted alkene (Zaitsev product), use a strong base like NaOH or KOH. If the goal is to form the less substituted alkene (Hofmann product), use a bulky base like potassium tert-butoxide.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Elimination Reactions
Elimination reactions involve the removal of a leaving group and a hydrogen atom from adjacent carbon atoms, resulting in the formation of a double bond. In the context of haloalkanes, these reactions can lead to the synthesis of alkenes. The most common types of elimination reactions are E1 and E2, which differ in their mechanisms and conditions.
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Recognizing Elimination Reactions.
Strong Bases
Strong bases are essential for promoting elimination reactions, particularly E2 mechanisms, where a strong base abstracts a proton while the leaving group departs. Common strong bases include sodium hydroxide (NaOH), potassium tert-butoxide (KOtBu), and sodium ethoxide (NaOEt). The choice of base can influence the regioselectivity and stereochemistry of the resulting alkene.
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Zaitsev's Rule
Zaitsev's Rule states that in elimination reactions, the more substituted alkene is typically the major product. This is due to the stability of more substituted alkenes, which are favored thermodynamically. Understanding this rule helps in predicting the outcome of reactions involving haloalkanes and the choice of base can also affect which alkene is formed.
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Related Practice
Textbook Question
Paying close attention to the stereochemical outcome, predict the product of these elimination reactions.
(c)
2
views
Textbook Question
Suggest an appropriate base to synthesize the alkene as the major product from the starting haloalkane.
(b)
1
views
Textbook Question
Show a mechanism for the following elimination reactions. Label the mechanism as E1 or E2.
(d)
1
views
Textbook Question
Show a mechanism for the following elimination reactions. Label the mechanism as E1 or E2.
(a)
1
views
Textbook Question
Paying close attention to the stereochemical outcome, predict the product of these elimination reactions.
(a)
1
views