Textbook Question
Show how you would synthesize the following primary alcohol by adding an appropriate Grignard reagent to formaldehyde.
(b)
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 14a
Show two ways you could synthesize each of the following secondary alcohol by adding an appropriate Grignard reagent to an aldehyde.
(a) 
Verified step by step guidance1
Step 1: Identify the target secondary alcohol structure. The first image shows a secondary alcohol with the hydroxyl group (-OH) attached to a carbon that is bonded to two other carbons. The second image also shows a secondary alcohol with a similar arrangement.
Step 2: Recall the general mechanism of Grignard reagent addition to aldehydes. A Grignard reagent (R-MgX) reacts with an aldehyde to form a secondary alcohol after protonation. The key is to choose the appropriate aldehyde and Grignard reagent combination to achieve the desired structure.
Step 3: For the first structure, one synthesis route involves using acetaldehyde (CH₃CHO) as the aldehyde and a Grignard reagent such as isopropyl magnesium bromide ((CH₃)₂CH-MgBr). The Grignard reagent adds to the carbonyl carbon of acetaldehyde, forming the secondary alcohol after protonation.
Step 4: Another synthesis route for the first structure involves using propanal (CH₃CH₂CHO) as the aldehyde and methyl magnesium bromide (CH₃-MgBr) as the Grignard reagent. The Grignard reagent adds to the carbonyl carbon of propanal, forming the secondary alcohol after protonation.
Step 5: For the second structure, one synthesis route involves using butanal (CH₃CH₂CH₂CHO) as the aldehyde and isopropyl magnesium bromide ((CH₃)₂CH-MgBr) as the Grignard reagent. Another route involves using isobutyraldehyde ((CH₃)₂CHCHO) as the aldehyde and ethyl magnesium bromide (CH₃CH₂-MgBr) as the Grignard reagent. Both combinations yield the desired secondary alcohol after protonation.
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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 aldehydes, they can lead to the formation of alcohols after hydrolysis.
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Carbonation of Grignard Reagents
Aldehyde Reactivity
Aldehydes are carbonyl compounds characterized by a carbon atom double-bonded to an oxygen atom and single-bonded to a hydrogen atom. They are more reactive than ketones due to the presence of the hydrogen atom, which makes them susceptible to nucleophilic attack by Grignard reagents. This reactivity is crucial for synthesizing secondary alcohols.
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Synthesis of Secondary Alcohols
Secondary alcohols can be synthesized by the reaction of Grignard reagents with aldehydes. The Grignard reagent acts as a nucleophile, attacking the carbonyl carbon of the aldehyde, leading to the formation of a tetrahedral intermediate. Upon hydrolysis, this intermediate yields a secondary alcohol, which is characterized by having the hydroxyl group (-OH) attached to a carbon that is bonded to two other carbons.
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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
6
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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
Show how you would synthesize the following primary alcohol by adding an appropriate Grignard reagent to formaldehyde.
(c)
5
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Textbook Question
Show how you would synthesize the following primary alcohol by adding an appropriate Grignard reagent to formaldehyde.
(a)
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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