Textbook Question
Show how you would add a Grignard reagent to an ester or a nitrile to synthesize
(c) pentan-2-one.
1
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Ch. 21 - Carboxylic Acid Derivatives
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 21, Problem 27
Draw a mechanism for the reaction of propanoyl chloride with 2 moles of phenylmagnesium bromide.
Verified step by step guidance1
Identify the reactants: Propanoyl chloride (CH3CH2COCl) is an acid chloride, and phenylmagnesium bromide (C6H5MgBr) is a Grignard reagent. Grignard reagents are nucleophiles that react with electrophiles like acid chlorides.
Understand the reaction mechanism: The reaction proceeds in two steps. In the first step, the nucleophilic phenyl group (C6H5-) from phenylmagnesium bromide attacks the carbonyl carbon of propanoyl chloride, forming a tetrahedral intermediate.
Account for the leaving group: The tetrahedral intermediate collapses, expelling the chloride ion (Cl-) as a leaving group. This results in the formation of a ketone, specifically propiophenone (CH3CH2COC6H5).
Introduce the second mole of phenylmagnesium bromide: The ketone (propiophenone) reacts with the second mole of phenylmagnesium bromide. The phenyl group (C6H5-) attacks the carbonyl carbon again, forming another tetrahedral intermediate.
Complete the reaction: The tetrahedral intermediate is protonated during the acidic workup step, resulting in the formation of a tertiary alcohol, specifically 1,1-diphenylpropan-2-ol (CH3CH(C6H5)2OH).
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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 phenylmagnesium bromide, are organomagnesium compounds that act as nucleophiles in organic reactions. They are formed by the reaction of an alkyl or aryl halide with magnesium metal in dry ether. Grignard reagents can react with carbonyl compounds to form alcohols, making them essential in nucleophilic addition reactions.
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Carbonation of Grignard Reagents
Nucleophilic Addition Mechanism
The nucleophilic addition mechanism involves the attack of a nucleophile on an electrophilic carbon atom, typically found in carbonyl groups. In this case, the carbonyl carbon of propanoyl chloride is attacked by the nucleophilic phenylmagnesium bromide, leading to the formation of a tetrahedral intermediate. This step is crucial for understanding how the reaction proceeds and ultimately leads to the formation of a new carbon-carbon bond.
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Acyl Chlorides
Acyl chlorides, like propanoyl chloride, are reactive carbonyl compounds that contain a chlorine atom bonded to the carbonyl carbon. They are highly electrophilic and readily undergo nucleophilic attack due to the electron-withdrawing effect of the chlorine atom. Understanding the reactivity of acyl chlorides is vital for predicting the outcome of reactions involving these compounds, especially in the presence of strong nucleophiles like Grignard reagents.
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01:57Recognizing acyl chlorides and anhydrides.
Related Practice
Textbook Question
Draw a mechanism for the acidic hydrolysis of the magnesium salt shown below to acetophenone.
1
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Textbook Question
Show how you would add a Grignard reagent to an ester or a nitrile to synthesize
(b) heptan-4-ol.
3
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Textbook Question
In which step(s) of the hydride reduction of an ester does the compound undergo reduction? (Hint: Count the bonds to oxygen.)
1
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Textbook Question
Propose a mechanism for the reduction of octanoyl chloride by lithium aluminum hydride.
1
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Textbook Question
Show how you would add a Grignard reagent to an ester or a nitrile to synthesize
(a) 4-phenylheptan-4-ol.
1
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