Skip to main content
Ch. 22 - Condensations and Alpha Substitutions of Carbonyl Compounds
Wade - Organic Chemistry 9th Edition
Wade9th EditionOrganic ChemistryISBN: 9780135213728Non è quello che usi tu?Cambia libro di testo
Tutti i libri di testoWade 9th EditionCh. 22 - Condensations and Alpha Substitutions of Carbonyl CompoundsProblema 75a
Capitolo 22, Problema 75a

The Knoevenagel condensation is a special case of the aldol condensation in which an active methylene compound reacts with an aldehyde or ketone, in the presence of a secondary amine as a basic catalyst, to produce a new C=C. Show the starting materials that made each of these by a Knoevenagel condensation.
(a)

Guida verificata passo dopo passo
1
Step 1: Identify the product structure. The given compound is a cyclic structure with a double bond (C=C) and two carbonyl groups (C=O) on either side of the double bond. This suggests it is the result of a Knoevenagel condensation reaction.
Step 2: Recall the general mechanism of Knoevenagel condensation. It involves the reaction of an active methylene compound (a compound with acidic hydrogens between two electron-withdrawing groups) with an aldehyde or ketone in the presence of a basic catalyst.
Step 3: Analyze the product to deduce the active methylene compound. The two carbonyl groups in the product suggest that the active methylene compound is likely malonic acid or a derivative such as diethyl malonate.
Step 4: Deduce the aldehyde or ketone used in the reaction. The cyclic structure with the double bond indicates that the aldehyde or ketone must have been cyclohexanone, as it provides the cyclic backbone and the site for the condensation reaction.
Step 5: Combine the starting materials. The Knoevenagel condensation reaction would involve cyclohexanone reacting with malonic acid (or a derivative) in the presence of a secondary amine catalyst to form the given 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:
8m

Concetti chiave

Ecco i concetti essenziali che devi comprendere per rispondere correttamente alla domanda.

Knoevenagel Condensation

Knoevenagel condensation is a reaction where an active methylene compound reacts with an aldehyde or ketone in the presence of a basic catalyst, typically a secondary amine. This reaction results in the formation of a carbon-carbon double bond (C=C) and is a key method for synthesizing α,β-unsaturated carbonyl compounds. Understanding this reaction is crucial for identifying starting materials and predicting products in organic synthesis.
Video consigliato:
05:53
Condensation Reactions

Active Methylene Compounds

Active methylene compounds are organic molecules that contain a methylene group (–CH2–) adjacent to a carbonyl group (C=O), making them highly nucleophilic. This unique structure allows them to participate in various reactions, including the Knoevenagel condensation. Recognizing these compounds is essential for determining which reactants can be used in the condensation process.
Video consigliato:
01:40
Defining meso compounds.

Aldol Condensation

Aldol condensation is a fundamental reaction in organic chemistry where aldehydes or ketones react to form β-hydroxy carbonyl compounds, which can further dehydrate to yield α,β-unsaturated carbonyl compounds. The Knoevenagel condensation can be viewed as a specific type of aldol condensation, emphasizing the importance of understanding aldol mechanisms and their variations in organic synthesis.
Video consigliato:
09:51
Crossed Aldol
Pratica correlata
Domanda del libro di testo

The following compounds can be synthesized by aldol condensations, followed by further reactions. (In each case, work backward from the target molecule to an aldol product, and show what compounds are needed for the condensation.)

(c)

1068
views
Domanda del libro di testo

The following compounds can be synthesized by aldol condensations, followed by further reactions. (In each case, work backward from the target molecule to an aldol product, and show what compounds are needed for the condensation.)

(b)

1218
views
Domanda del libro di testo

The Knoevenagel condensation is a special case of the aldol condensation in which an active methylene compound reacts with an aldehyde or ketone, in the presence of a secondary amine as a basic catalyst, to produce a new C=C. Show the starting materials that made each of these by a Knoevenagel condensation.

(c)

952
views
Domanda del libro di testo

The following compounds can be synthesized by aldol condensations, followed by further reactions. (In each case, work backward from the target molecule to an aldol product, and show what compounds are needed for the condensation.)

(a)

1440
views
Domanda del libro di testo

The Knoevenagel condensation is a special case of the aldol condensation in which an active methylene compound reacts with an aldehyde or ketone, in the presence of a secondary amine as a basic catalyst, to produce a new C=C. Show the starting materials that made each of these by a Knoevenagel condensation.

(d)

712
views
Domanda del libro di testo

The Knoevenagel condensation is a special case of the aldol condensation in which an active methylene compound reacts with an aldehyde or ketone, in the presence of a secondary amine as a basic catalyst, to produce a new C=C. Show the starting materials that made each of these by a Knoevenagel condensation.

(b)

1053
views