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 14c
Show two ways you could synthesize each of the following secondary alcohol by adding an appropriate Grignard reagent to an aldehyde.
(c) 
Verified step by step guidance1
Step 1: Identify the target molecule, which is a secondary alcohol. The secondary alcohol shown has a cyclohexyl group, a hydroxyl group (-OH), and a prop-2-enyl group attached to the same carbon atom.
Step 2: Recall the general mechanism for synthesizing secondary alcohols using Grignard reagents. A Grignard reagent (R-MgX) reacts with an aldehyde to form a secondary alcohol after protonation.
Step 3: First synthesis route: Use cyclohexylmagnesium bromide (C6H11-MgBr) as the Grignard reagent and prop-2-enal (CH2=CH-CHO) as the aldehyde. The Grignard reagent will attack the carbonyl carbon of the aldehyde, forming the secondary alcohol after protonation.
Step 4: Second synthesis route: Use prop-2-enylmagnesium bromide (CH2=CH-CH2-MgBr) as the Grignard reagent and cyclohexanecarboxaldehyde (C6H11-CHO) as the aldehyde. The Grignard reagent will attack the carbonyl carbon of the aldehyde, forming the secondary alcohol after protonation.
Step 5: In both cases, ensure the reaction is carried out in an anhydrous environment to prevent the Grignard reagent from reacting with water. After the reaction, protonate the intermediate with a mild acid (e.g., HCl or H2O) to yield the secondary 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 represented as R-MgX, where R is an organic group and X is a halogen. They are highly reactive and act as nucleophiles, allowing them to attack electrophilic carbon centers, such as those found in carbonyl compounds. This property makes them essential for forming new carbon-carbon bonds in organic synthesis.
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Carbonation of Grignard Reagents
Aldehyde Reactivity
Aldehydes are carbonyl compounds characterized by the presence of a carbonyl group (C=O) bonded to at least one hydrogen atom. They are more reactive than ketones due to the presence of the hydrogen, which makes the carbonyl carbon more electrophilic. This reactivity allows Grignard reagents to effectively add to aldehydes, leading to the formation of secondary alcohols upon hydrolysis.
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Synthesis of Secondary Alcohols
Secondary alcohols can be synthesized by the nucleophilic addition of Grignard reagents to aldehydes. When a Grignard reagent reacts with an aldehyde, it forms a tetrahedral intermediate, which upon protonation yields a secondary alcohol. Understanding the mechanism of this reaction is crucial for designing synthetic pathways in organic chemistry.
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Related Practice
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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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 following tertiary alcohol by adding an appropriate Grignard reagent to a ketone.
d. 2-cyclopentylpentan-2-ol
2
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