An efficient synthetic protocol based on a new concept named "the pseudo-intramolecular process" is developed. Substrates are brought closed to each other by forming a salt, and this spatial proximity facilitates an efficient reaction like an intramolecular process, despite actually proceeding via an intermolecular pathway. This concept can be widely applied in organic synthesis. For instance, α-aryl-β-keto esters undergo a transacylation with amines accompanied by high efficiency, regioselectivity, and chemoselectivity. On the other hand, α-nitro-β-keto nitriles react via a tandem cyclization to afford polyfunctionalized azaheterocyclic compounds, which cannot be easily prepared by alternative methods. These synthetic protocols are practically useful because each reaction can be conducted without using any special reagent under mild reaction conditions through only simple experimental manipulations.
Keywords: acylation; azaheterocycles; keto ester; pseudo-intramolecular process; tandem cyclization.