Various O-protected glycol- and racemic lactaldehydes 3 and 6 as well as O-allyl protected racemic α-hydroxyaldehydes 7 (R 1 =Et, Pr, Bu) have been prepared to investigate and perform a stereoselective Kiliani-Fischer synthesis by hydroxynitrile lyase (HNL) catalyzed addition of HCN. From all protecting groups investigated the allyl moiety was most suitable. (R)-PaHNL from bitter almonds (Prunus amygdalus), yielding the (2S)-cyanohydrins 8-10, was found to be a more stereoselective catalyst than (S)-MeHNL from maniok (Manihot esculenta). While (R)-PaHNL led to enantiomeric excesses =<93%, with (S)-MeHNL the (2R)-cyanohydrins 8-10 were obtained with enantiomeric excesses =<78%.