Ambident nucleophiles pyrrole

Santaniello et al.125 have N-alkylated pyrrole and indole (71) in the presence of crown-ether catalysts. The indolyl anion also behaves as an ambident nucleophile alkylation occurs at nitrogen and at C-3.126... 

The ambident nucleophilic character of enaminones is again demonstrated by the reaction with keto carbenes, produced in situ from diazoketones. Acyclic enaminones react via the -position to directly yield pyrroles (equation 11). Cyclic enaminones are shown to react at the nitrogen to give adducts which can be cyclized with KOH to... 

Ambident anions are mesomeric, nucleophilic anions which have at least two reactive centers with a substantial fraction of the negative charge distributed over these cen-ters ) ). Such ambident anions are capable of forming two types of products in nucleophilic substitution reactions with electrophilic reactants . Examples of this kind of anion are the enolates of 1,3-dicarbonyl compounds, phenolate, cyanide, thiocyanide, and nitrite ions, the anions of nitro compounds, oximes, amides, the anions of heterocyclic aromatic compounds e.g. pyrrole, hydroxypyridines, hydroxypyrimidines) and others cf. Fig. 5-17. 

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