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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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 15d
Show how you would synthesize following tertiary alcohol by adding an appropriate Grignard reagent to a ketone.
d. 2-cyclopentylpentan-2-ol
Verified step by step guidance1
Identify the target molecule: The target molecule is 2-cyclopentylpentan-2-ol, 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 the tertiary alcohol, the ketone must have the same carbon skeleton as the target molecule, minus the group added by the Grignard reagent. In this case, the ketone would be cyclopentyl methyl ketone (2-cyclopentylpropan-2-one).
Determine the Grignard reagent: The Grignard reagent must add the appropriate alkyl group to the ketone to form the tertiary alcohol. In this case, the Grignard reagent would be ethylmagnesium bromide (CH₃CH₂MgBr).
Write the reaction mechanism: The Grignard reagent (ethylmagnesium bromide) will attack the carbonyl carbon of the ketone (cyclopentyl methyl ketone), forming a tetrahedral alkoxide intermediate. This intermediate will then be protonated during the acidic workup to yield the tertiary alcohol.
Summarize the synthesis: Combine cyclopentyl methyl ketone with ethylmagnesium bromide in an anhydrous ether solvent, followed by an acidic workup (e.g., H₃O⁺), to synthesize 2-cyclopentylpentan-2-ol.
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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 to form carbon-carbon bonds. They are created by reacting an alkyl or aryl halide with magnesium metal in anhydrous ether. When added to carbonyl compounds like ketones, they can facilitate the formation of alcohols through nucleophilic addition.
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Carbonation of Grignard Reagents
Nucleophilic Addition to Ketones
Nucleophilic addition is a fundamental reaction in organic chemistry where a nucleophile attacks an electrophilic carbon atom in a carbonyl group. In the case of ketones, the carbonyl carbon is susceptible to attack by nucleophiles such as Grignard reagents, leading to the formation of an alkoxide intermediate. This intermediate can then be protonated to yield the corresponding alcohol.
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Synthesis of Tertiary Alcohols
Tertiary alcohols are synthesized from ketones by adding two alkyl groups to the carbon atom of the carbonyl. When a Grignard reagent reacts with a ketone, it adds to the carbonyl carbon, resulting in a tertiary alcohol after protonation. The specific structure of the Grignard reagent determines the final structure of the tertiary alcohol produced.
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Related Practice
Textbook Question
Show how you would synthesize following tertiary alcohol by adding an appropriate Grignard reagent to a ketone.
c. 1-ethylcyclopentanol
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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
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Textbook Question
Show how you would add Grignard reagent to acid chloride or ester to synthesize the following alcohols.
c. dicyclohexylphenylmethanol
612
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Textbook Question
Propose a mechanism for the reaction of acetyl chloride with phenylmagnesium bromide to give 1,1-diphenylethanol.
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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)
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