Skip to main content
Ch. 21 - Carboxylic Acid Derivatives
Wade - Organic Chemistry 9th Edition
Wade9th EditionOrganic ChemistryISBN: 9780135213728Non è quello che usi tu?Cambia libro di testo
Capitolo 21, Problema 28c

Show how you would add a Grignard reagent to an ester or a nitrile to synthesize
(c) pentan-2-one.

Guida verificata passo dopo passo
1
Identify the target molecule, pentan-2-one, which is a ketone. The goal is to synthesize this compound using a Grignard reagent and either an ester or a nitrile as the starting material.
Choose an appropriate Grignard reagent. To form pentan-2-one, the Grignard reagent should add a two-carbon chain to the starting material. Use ethylmagnesium bromide (CH₃CH₂MgBr) as the Grignard reagent.
If starting with an ester, select an ester that will yield the desired ketone after the Grignard reaction. For pentan-2-one, use methyl propanoate (CH₃CH₂COOCH₃) as the ester. The Grignard reagent will add to the carbonyl carbon of the ester.
If starting with a nitrile, select a nitrile that will yield the desired ketone after the Grignard reaction. For pentan-2-one, use propanenitrile (CH₃CH₂CN). The Grignard reagent will add to the carbon of the nitrile group, forming an imine intermediate, which is then hydrolyzed to the ketone.
Perform the reaction: (1) React the Grignard reagent with the ester or nitrile under anhydrous conditions to form the intermediate. (2) For the ester, the intermediate will collapse to form the ketone directly. For the nitrile, hydrolyze the imine intermediate with aqueous acid to yield the ketone, pentan-2-one.

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:
2m

Concetti chiave

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

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 nucleophiles that can add to electrophilic carbonyl groups, such as esters and nitriles, facilitating the formation of new carbon-carbon bonds. Understanding their reactivity is crucial for synthesizing ketones and other carbonyl compounds.
Video consigliato:
02:12
Carbonation of Grignard Reagents

Ester Reactivity

Esters are organic compounds characterized by the functional group RCOOR', where R and R' are hydrocarbon chains. They can undergo nucleophilic addition reactions with Grignard reagents, leading to the formation of tertiary alcohols after hydrolysis. Recognizing the mechanism of this reaction is essential for synthesizing ketones like pentan-2-one from esters.
Video consigliato:
02:39
Ester Nomenclature

Nitrile Reactivity

Nitriles are compounds containing the cyano group (-C≡N) and can also react with Grignard reagents. When a Grignard reagent adds to a nitrile, it forms an intermediate imine, which can be hydrolyzed to yield a ketone. This pathway is significant for synthesizing ketones, providing an alternative route to the desired product.
Video consigliato:
01:01
Nitrile Nomenclature