Textbook Question
Show how you would convert propan-1-ol to the following compounds using tosylate intermediates. You may use whatever additional reagents are needed.
a. 1-bromopropane
b. propan-1-amine, CH3CH2CH2NH2
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Ch.11 - Reactions 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 11, Problem 10c,d
Show how you would convert propan-1-ol to the following compounds using tosylate intermediates. You may use whatever additional reagents are needed.
c. CH3CH2CH2OCH2CH3, ethyl proyl ether
d. CH3CH2CH2CN, butyronitrile
Verified step by step guidance1
Step 1: Begin with propan-1-ol (CH3CH2CH2OH). Convert the hydroxyl group (-OH) into a good leaving group by reacting it with p-toluenesulfonyl chloride (TsCl) in the presence of a base like pyridine. This forms propyl tosylate (CH3CH2CH2OTs).
Step 2: For part (c), to synthesize ethyl propyl ether (CH3CH2CH2OCH2CH3), perform a Williamson ether synthesis. React the propyl tosylate (CH3CH2CH2OTs) with sodium ethoxide (CH3CH2ONa). The ethoxide ion acts as a nucleophile, displacing the tosyl group and forming the ether bond.
Step 3: For part (d), to synthesize butyronitrile (CH3CH2CH2CN), perform a nucleophilic substitution reaction. React the propyl tosylate (CH3CH2CH2OTs) with sodium cyanide (NaCN). The cyanide ion (CN⁻) acts as a nucleophile, displacing the tosyl group and forming the nitrile group.
Step 4: Ensure proper reaction conditions for each step. For the Williamson ether synthesis, use an aprotic solvent like dimethyl sulfoxide (DMSO) to favor the SN2 mechanism. For the nitrile synthesis, also use an aprotic solvent to enhance the nucleophilicity of CN⁻.
Step 5: After each reaction, purify the product using appropriate techniques such as distillation or recrystallization, and confirm the structure of the final compounds using spectroscopic methods like NMR or IR.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Tosylate Formation
Tosylates are formed by reacting alcohols with tosyl chloride (TsCl) in the presence of a base, converting the hydroxyl group into a better leaving group. This transformation is crucial for facilitating nucleophilic substitution reactions, as the tosylate can be displaced by various nucleophiles, allowing for the synthesis of more complex molecules.
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02:26
Formation of Enolates
Nucleophilic Substitution Reactions
Nucleophilic substitution reactions involve the replacement of a leaving group in a molecule with a nucleophile. In the context of converting propan-1-ol to ethers or nitriles, the tosylate intermediate serves as a substrate for nucleophiles like alkoxides or cyanide ions, which attack the electrophilic carbon, leading to the desired product.
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01:47Nucleophiles and Electrophiles can react in Substitution Reactions.
Ether Synthesis
Ether synthesis can be achieved through the reaction of an alkoxide ion with an alkyl halide or tosylate. In this case, the reaction of the tosylate derived from propan-1-ol with an appropriate alkoxide will yield the desired ether, such as CH3CH2CH2OCH2CH3, demonstrating the utility of tosylates in forming ethers efficiently.
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03:50The Mechanism of Williamson Ether Synthesis.
Related Practice
Textbook Question
Predict the major products of the following reactions.
(d) the tosylate of cyclohexylmethanol + excess NH3
(e) n-butyl tosylate + sodium acetylide, H–C≡C:– +Na
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Textbook Question
Predict the products of the following reactions.
(c) 1-methylcyclohexanol + H2SO4, heat
(d) product of (c) + H2, Pt
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Textbook Question
Propose a mechanism for the reaction of
(a) 1-methylcyclohexanol with HBr to form 1-bromo-1-methylcyclohexane.
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Textbook Question
Predict the products of the following reactions.
(a) cyclohexylmethanol + TsCl/pyridine
(b) product of (a) + LiAlH4
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Textbook Question
Predict the major products of the following reactions.
(a) ethyl tosylate + potassium tert-butoxide
(b) isobutyl tosylate + NaI
(c) (R)-2-hexyl tosylate + NaCN
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