Textbook Question
Predict the products formed when cyclohexanone reacts with the following reagents.
(i) hydrazine, then hot, fused KOH
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Ch. 18 - Ketones and Aldehydes
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 18, Problem 54a
Predict the products formed when cyclohexanecarbaldehyde reacts with the following reagents.
(a) PhMgBr, then H3O+
Verified step by step guidance1
Step 1: Recognize the type of reaction. Cyclohexanecarbaldehyde contains an aldehyde functional group (-CHO). When treated with a Grignard reagent like PhMgBr, the reaction involves nucleophilic addition to the carbonyl group.
Step 2: Analyze the Grignard reagent. PhMgBr consists of a phenyl group (Ph-) bonded to magnesium bromide (MgBr). The phenyl group acts as a nucleophile, attacking the electrophilic carbon of the aldehyde.
Step 3: Write the mechanism for the nucleophilic addition. The phenyl group (Ph-) attacks the carbonyl carbon of cyclohexanecarbaldehyde, breaking the π bond of the carbonyl group. This forms a tetrahedral intermediate with a negatively charged oxygen atom.
Step 4: Consider the second reagent, H3O+. The acidic workup (H3O+) protonates the negatively charged oxygen atom in the intermediate, converting it into a hydroxyl group (-OH). This results in the formation of an alcohol.
Step 5: Predict the final product. The reaction produces a secondary alcohol where the phenyl group (Ph-) is attached to the carbon that was originally part of the aldehyde group in cyclohexanecarbaldehyde.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Grignard Reagents
Grignard reagents, such as PhMgBr, are organomagnesium compounds that act as nucleophiles in organic reactions. They readily react with electrophiles, such as carbonyl groups, to form alcohols. In this case, PhMgBr will attack the carbonyl carbon of cyclohexanecarbaldehyde, leading to the formation of a magnesium alkoxide intermediate.
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Carbonation of Grignard Reagents
Carbonyl Chemistry
Carbonyl compounds, characterized by a carbon-oxygen double bond, are key functional groups in organic chemistry. They can undergo various reactions, including nucleophilic addition, where nucleophiles attack the electrophilic carbon atom. Understanding the reactivity of carbonyls is crucial for predicting the products of reactions involving aldehydes and ketones.
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Acid Workup
An acid workup, typically involving H3O+, is a common step in organic synthesis following nucleophilic addition reactions. This process protonates the alkoxide intermediate formed after the Grignard reaction, converting it into a stable alcohol. The acid workup is essential for isolating the final product and ensuring the reaction reaches completion.
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Related Practice
Textbook Question
Predict the products formed when cyclohexanone reacts with the following reagents.
(l) acidic hydrolysis of the product from (k)
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Textbook Question
Predict the products formed when cyclohexanecarbaldehyde reacts with the following reagents.
b. Tollens reagent
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Textbook Question
Predict the products formed when cyclohexanone reacts with the following reagents.
(k) sodium cyanide
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Textbook Question
Predict the products formed when cyclohexanecarbaldehyde reacts with the following reagents.
(d) excess ethanol and acid
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Textbook Question
Predict the products formed when cyclohexanecarbaldehyde reacts with the following reagents.
(c) semicarbazide and weak acid
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