The preparation of two new series of chiral 1,2-diamines and their use in the [ZnR2-diamine]-catalyzedasymmetrichydrosilylation of acetophenone with poly(methylhydrosiloxane) (PMHS) in an aprotic medium is reported. The effect of structural modifications of the secondary diamine ligand, in particular a possible cooperative effect of two different types of chiral centers, on the N-benzylic side-arms