Domanda del libro di testo
Propose mechanisms for the following reactions. In most cases, more products are formed than are shown here. You only need to explain the formation of the products shown, however.
(b)
679
views
Ch.11 - Reactions of Alcohols
Wade9th EditionOrganic ChemistryISBN: 9780135213728
Non è quello che usi tu?Cambia libro di testoScegli un libro di testo diverso
TOC.tableOfContents
- 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
Capitolo 11, Problema 54
Under acid catalysis, tetrahydrofurfuryl alcohol reacts to give surprisingly good yields of dihydropyran. Propose a mechanism to explain this useful synthesis.
Guida verificata passo dopo passo1
Step 1: Protonation of the hydroxyl group - Under acidic conditions, the hydroxyl group (-OH) of tetrahydrofurfuryl alcohol is protonated by H⁺, forming a positively charged oxonium ion. This step increases the electrophilicity of the oxygen atom and prepares the molecule for subsequent reactions.
Step 2: Formation of a carbocation - The protonated hydroxyl group undergoes elimination of water (H₂O), leading to the formation of a carbocation at the carbon adjacent to the oxygen atom. This carbocation is stabilized by resonance with the oxygen atom in the tetrahydrofuran ring.
Step 3: Intramolecular nucleophilic attack - The oxygen atom in the tetrahydrofuran ring acts as a nucleophile and attacks the carbocation, forming a new bond between the oxygen and the carbocation carbon. This step results in the formation of a six-membered ring intermediate.
Step 4: Deprotonation to form the double bond - A proton is removed from the intermediate, leading to the formation of a double bond in the six-membered ring. This step completes the synthesis of dihydropyran.
Step 5: Final product - The reaction yields dihydropyran, a six-membered ring containing an oxygen atom and a double bond, as the final product.
Risposta video verificata per un problema simile:
Questa soluzione video è stata consigliata dai nostri tutor come utile per risolvere questo problema.
Durata del video:
4mConcetti chiave
Ecco i concetti essenziali che devi comprendere per rispondere correttamente alla domanda.
Acid Catalysis
Acid catalysis involves the acceleration of a chemical reaction by the presence of an acid, which donates protons (H+) to the reactants. This process can enhance the electrophilicity of certain functional groups, making them more reactive. In the context of organic reactions, acids can facilitate the formation of carbocations, which are key intermediates in many mechanisms, including the conversion of tetrahydrofurfuryl alcohol to dihydropyran.
Video consigliato:
Percorso guidato
2:50
Acid-Base Catalysis Concept 3
Mechanism of Dihydropyran Formation
The formation of dihydropyran from tetrahydrofurfuryl alcohol typically involves a series of steps including protonation, nucleophilic attack, and dehydration. Initially, the alcohol is protonated to form a more reactive carbocation. This carbocation can then undergo intramolecular nucleophilic attack by an alcohol group, leading to the formation of a cyclic ether, followed by loss of water to yield dihydropyran.
Video consigliato:
02:26Formation of Enolates
Carbocation Stability
Carbocation stability is a crucial concept in organic chemistry, as the stability of these positively charged intermediates influences reaction pathways. Tertiary carbocations are more stable than secondary or primary ones due to hyperconjugation and inductive effects. In the proposed mechanism, the formation of a stable carbocation intermediate from tetrahydrofurfuryl alcohol is essential for the efficient synthesis of dihydropyran under acid catalysis.
Video consigliato:
05:58Determining Carbocation Stability
Pratica correlata
Domanda del libro di testo
Give the structures of the intermediates and products V through Z.
1667
views
1
rank
Domanda del libro di testo
Propose mechanisms for the following reactions. In most cases, more products are formed than are shown here. You only need to explain the formation of the products shown, however.
(c)
588
views
Domanda del libro di testo
Propose mechanisms for the following reactions. In most cases, more products are formed than are shown here. You only need to explain the formation of the products shown, however.
(a)
934
views
Domanda del libro di testo
Compound A is an optically active alcohol. Treatment with chromic acid converts A into a ketone, B. In a separate reaction, A is treated with PBr3, converting A into compound C. Compound C is purified, and then it is allowed to react with magnesium in ether to give a Grignard reagent, D. Compound B is added to the resulting solution of the Grignard reagent. After hydrolysis of the initial product (E), this solution is found to contain 3,4-dimethylhexan-3-ol. Propose structures for compounds A, B, C, D, and E.
1798
views
Domanda del libro di testo
The compound shown below has three different types of OH groups, all with different acidities. Show the structure produced after this compound is treated with different amounts of NaH followed by a methylating reagent. Add a brief explanation.
(a) 1 equivalent of NaH, followed by 1 equivalent of CH3I and heat
(b) 2 equivalents of NaH, followed by 2 equivalents of CH3I and heat
(c) 3 equivalents of NaH, followed by 3 equivalents of CH3I and heat
1093
views