➠Enamines are good nucleophiles which can be used as synthetic equivalents of ketone enolate ion.
➠Stark enamine is used for the alkylation or acylation of a ketone using different reagents.
➠Enamines are alpha-beta unsaturated amines prepared from the secondary amines and a carbonyl compound.
➠E.g./Mechanism:-
➠Enamines are less nucleophilic in nature than enolate ion, therefore, they require high temperature at the reaction time.
➠Enamines also gives 1,4-addition to the conjugated system (Michael addition).
➠The enamines are regeoselective, it means that with unsymmetrical ketones, the less substituted enamine is formed preferentially.
E.g.
➠During the formation of enamine, a more conjugated enamine will be formed because of the stability. E.g.
➠A major problem with an enamine is that the nitrogen atom of an enamine is alkylated if the simple alkyl halides are used (Me-I).
Hence, in order to prevent this problem, more bulkier alkylating reagents are recommended➡(Disadvantage).
➠Some important examples are given below:-
End
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