Novel trans-4-hydroxy-L-proline-derived N,N'-dioxides have been developed and used as efficient organocatalysts for the one-pot three-component Strecker reaction with an aldehyde, (1,1-diphenyl)methylamine, and TMSCN. Both aromatic and aliphatic aldehydes were found to be suitable substrates. The corresponding alpha-amino nitriles were obtained in high yields with up to 95 % ee (ee=enantiomeric excess) under mild conditions. Optically pure products could be obtained after a single recrystallization. The catalyst can be easily prepared from trans-4-hydroxy-L-proline and a diamine in three steps. Based on the experimental results and the observed absolute configurations of the products, a possible transition state has been proposed to explain the origin of the asymmetric induction.