Textbook Question
Propose mechanisms for the following reactions.
(a)
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Ch. 19 - Amines
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 19, Problem 46b
Propose mechanisms for the following reactions.
(b) 
Verified step by step guidance1
Step 1: Analyze the starting material and product. The starting material is a ketone with a cyano group (-CN) attached to a cyclohexane ring. The product is a secondary amine in a bicyclic structure. This suggests a reduction and cyclization mechanism.
Step 2: Recognize the reagents used. The reaction involves H2 gas, a platinum (Pt) catalyst, and acidic conditions (H+). These conditions are typical for catalytic hydrogenation, which reduces functional groups such as ketones and nitriles.
Step 3: Propose the reduction of the cyano group (-CN). Under hydrogenation conditions, the cyano group is reduced to a primary amine (-CH2NH2). This step involves the addition of hydrogen atoms to the carbon and nitrogen of the cyano group.
Step 4: Propose the reduction of the ketone group. The ketone is reduced to a secondary alcohol (-CH(OH)-) via hydrogenation. This step involves the addition of hydrogen atoms to the carbonyl carbon and oxygen.
Step 5: Propose the cyclization mechanism. Under acidic conditions, the primary amine (-CH2NH2) can attack the secondary alcohol (-CH(OH)-) in an intramolecular nucleophilic substitution reaction. This leads to the formation of a bicyclic structure with a secondary amine (-NH-) as the final product.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Reaction Mechanisms
A reaction mechanism is a step-by-step description of how a chemical reaction occurs at the molecular level. It outlines the sequence of elementary steps, including bond breaking and formation, and the intermediates formed during the reaction. Understanding mechanisms is crucial for predicting the products and understanding the kinetics and thermodynamics of the reaction.
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Types of Organic Reactions
Organic reactions can be classified into several types, including substitution, addition, elimination, and rearrangement reactions. Each type has distinct characteristics and mechanisms. Recognizing the type of reaction helps in predicting the behavior of reactants and the nature of the products formed, which is essential for proposing accurate mechanisms.
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Curved Arrow Notation
Curved arrow notation is a visual representation used in organic chemistry to illustrate the movement of electrons during chemical reactions. Arrows indicate the direction of electron flow, showing how bonds are broken and formed. Mastery of this notation is vital for accurately depicting reaction mechanisms and understanding the underlying processes in organic reactions.
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Related Practice
Textbook Question
The two most general amine syntheses are the reductive amination of carbonyl compounds and the reduction of amides. Show how these techniques can be used to accomplish the following syntheses.
(b) benzaldehyde → benzylamine
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Textbook Question
Synthesize from benzene. (Hint: All of these require diazonium ions.)
(d) 4-methoxyaniline
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Textbook Question
The two most general amine syntheses are the reductive amination of carbonyl compounds and the reduction of amides. Show how these techniques can be used to accomplish the following syntheses.
(a) benzoic acid → benzylamine
2
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Textbook Question
Synthesize from benzene. (Hint: All of these require diazonium ions.)
(c) 2-methyl-5-hydroxybenzoic acid
1
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Textbook Question
The two most general amine syntheses are the reductive amination of carbonyl compounds and the reduction of amides. Show how these techniques can be used to accomplish the following syntheses.
(c) pyrrolidine → N-ethylpyrrolidine