Textbook Question
Show how you would accomplish the following conversions.
c. trans-hex-3-ene to meso-hexane-3,4-diol
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Ch.8 - Reactions of Alkenes
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 8, Problem 35b
Show how you would accomplish the following conversions.
b. cis-hex-3-ene to (d,l)-hexane-3,4-diol
Verified step by step guidance1
Step 1: Analyze the starting material and the product. The starting material is cis-hex-3-ene, which is an alkene. The product is (d,l)-hexane-3,4-diol, a racemic mixture of diols. This indicates that the reaction involves the addition of hydroxyl groups (-OH) to the double bond in a stereoselective manner.
Step 2: Recognize the reaction type. The conversion of an alkene to a diol is typically achieved through a dihydroxylation reaction. A common reagent for this transformation is osmium tetroxide (OsO₄) in the presence of a co-oxidant such as N-methylmorpholine N-oxide (NMO). Alternatively, potassium permanganate (KMnO₄) under mild conditions can also be used.
Step 3: Understand the stereochemistry. The cis configuration of the alkene ensures that the hydroxyl groups will be added to the same face of the double bond, resulting in a syn addition. However, because the product is racemic, both enantiomers (d and l forms) are formed due to the planar nature of the alkene, which allows attack from either side.
Step 4: Write the reaction mechanism. The alkene reacts with OsO₄ to form a cyclic osmate ester intermediate. This intermediate is then hydrolyzed in the presence of water to yield the diol. If KMnO₄ is used, the alkene reacts to form a cyclic manganate ester, which is similarly hydrolyzed to produce the diol.
Step 5: Summarize the conditions. To achieve the conversion, use either OsO₄ with NMO or KMnO₄ under mild conditions, followed by hydrolysis. These reagents will ensure the formation of the racemic mixture of hexane-3,4-diol.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Alkene Reactivity
Alkenes, such as cis-hex-3-ene, are reactive due to the presence of a carbon-carbon double bond. This double bond can undergo various reactions, including addition reactions, where atoms or groups are added across the double bond. Understanding the reactivity of alkenes is crucial for predicting the products of their transformations.
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Alkene Metathesis Concept 1
Stereochemistry
Stereochemistry refers to the spatial arrangement of atoms in molecules and how this affects their chemical behavior. In the conversion of cis-hex-3-ene to racemic hexane-3,4-diol, the stereochemistry of the starting alkene influences the stereochemical outcome of the product, leading to a mixture of enantiomers due to the formation of chiral centers.
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Hydroxylation Reactions
Hydroxylation is a chemical reaction that introduces hydroxyl (-OH) groups into a molecule. In this case, the conversion involves the addition of two hydroxyl groups to the double bond of cis-hex-3-ene, resulting in the formation of hexane-3,4-diol. This reaction can be achieved through various methods, such as syn-dihydroxylation using reagents like osmium tetroxide or potassium permanganate.
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Related Practice
Textbook Question
Predict the major products of the following reactions, including stereochemistry.
e. trans-pent-2-ene + OsO4/H2O2
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Textbook Question
Give structures of the alkenes that would give the following products upon ozonolysis–reduction.
(a)
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Textbook Question
Show how you would accomplish the following conversions.
a. cis-hex-3-ene to meso-hexane-3,4-diol
Textbook Question
Show how you would accomplish the following conversions.
d. trans-hex-3-ene to (d,l)-hexane-3,4-diol
1
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Textbook Question
Predict the major products of the following reactions, including stereochemistry.
f. trans-pent-2-ene + peroxyacetic acid in water
1
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