A 2-nitrated 3-oxoester reacted with amines or alcohols to afford unsymmetrical malonic acid derivatives as a result of nucleophilic substitution accompanying C–C bond cleavage. The 2-nitrated 3-oxoester easily formed ammonium salts with amines. When the amine is liberated from the salt under equilibrium, nucleophilic amine and electrophilic keto ester locate close to each other. This intimate pair effect causes a pseudo intramolecular reaction to occur, giving rise to effective substitution under mild conditions.