Textbook Question
Show two ways you could synthesize each of the following secondary alcohol by adding an appropriate Grignard reagent to an aldehyde.
(a)
1
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Ch.10 - Structure and Synthesis of Alcohols
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 10, Problem 15c
Show how you would synthesize following tertiary alcohol by adding an appropriate Grignard reagent to a ketone.
c. 1-ethylcyclopentanol
Verified step by step guidance1
Identify the target molecule: The target molecule is 1-ethylcyclopentanol, which is a tertiary alcohol. Tertiary alcohols can be synthesized by reacting a ketone with a Grignard reagent.
Determine the structure of the ketone: To form 1-ethylcyclopentanol, the ketone must have a cyclopentane ring with a carbonyl group (C=O) at the appropriate position. The ketone should be 1-ethylcyclopentanone, where the ethyl group is already attached to the cyclopentane ring.
Choose the Grignard reagent: To add the necessary group to the ketone and form the tertiary alcohol, the Grignard reagent must provide a methyl group (CH₃). The appropriate Grignard reagent is methylmagnesium bromide (CH₃MgBr).
Write the reaction mechanism: The Grignard reagent (CH₃MgBr) will attack the carbonyl carbon of 1-ethylcyclopentanone. This nucleophilic addition forms a tetrahedral intermediate, where the oxygen atom becomes negatively charged.
Complete the reaction: The intermediate is then protonated by adding water (H₂O) or a dilute acid, converting the negatively charged oxygen into a hydroxyl group (-OH). This results in the formation of 1-ethylcyclopentanol, the desired tertiary alcohol.
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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 are organomagnesium compounds that are highly reactive and used in organic synthesis. They are formed by reacting alkyl or aryl halides with magnesium metal in dry ether. Grignard reagents act as nucleophiles, attacking electrophilic carbon centers, such as those in carbonyl compounds, to form new carbon-carbon bonds.
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Ketones
Ketones are organic compounds characterized by a carbonyl group (C=O) bonded to two carbon atoms. They are important intermediates in organic synthesis and can react with Grignard reagents to form tertiary alcohols. The reaction involves the nucleophilic attack of the Grignard reagent on the carbonyl carbon, followed by protonation to yield the alcohol.
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Tertiary Alcohols
Tertiary alcohols are alcohols where the hydroxyl (-OH) group is attached to a carbon atom that is connected to three other carbon atoms. They are typically formed through the reaction of Grignard reagents with ketones. The structure of tertiary alcohols influences their reactivity and stability, making them important in various chemical reactions and applications.
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Related Practice
Textbook Question
Show how you would add Grignard reagent to acid chloride or ester to synthesize the following alcohols.
a. Ph3C–OH
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Textbook Question
Show how you would synthesize following tertiary alcohol by adding an appropriate Grignard reagent to a ketone.
b. Ph3COH
3
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Textbook Question
Propose a mechanism for the reaction of acetyl chloride with phenylmagnesium bromide to give 1,1-diphenylethanol.
8
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Textbook Question
Show how you would synthesize following tertiary alcohol by adding an appropriate Grignard reagent to a ketone.
d. 2-cyclopentylpentan-2-ol
2
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Textbook Question
Show two ways you could synthesize each of the following secondary alcohol by adding an appropriate Grignard reagent to an aldehyde.
(c)
10
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