The use of cinchona alkaloids (cinchonidine, cinchonine, quinine, quinidine, alpha-isocinchonine, alpha-isoquinidine, gamma-isoquinidine) in the Orito reaction (hydrogenation of ethyl pyruvate and ethyl benzoylformate) strongly supports the structure of the intermediate complex (cinchona alkaloid "anti-open" conformer-pyruvate 1 : 1 complex); in addition, so far unknown stereochemical conditions have been identified and the utilization of rigid cinchona conformers in the study of asymmetric syntheses have been generalized.