Ring opening of aziridine with dialkyl amine took place readily in the presence of catalytic amounts of tri-n-butylphosphane (10 mol%) in the mixture of CH3CN/H2O (10:1), giving corresponding vicinal diamines in mediate to high yields (58–95%) with good regioselectivitie, while aromatic secondary amine could not react under the same conditions. Tri-n-butylphosphane exhibited different catalytic selectivity to amines from Lewis acid catalysts.

An efficient and water tolerant method for the synthesis of β-haloamines is described utilizing hydrated nickel (II) halides (NiX2·nH2O X = Cl, Br, I) and aziridines as starting materials. N-Tosylaziridines reacted with NiCl2·6H2O or NiI2·6H2O giving β-chloro- or β-iodoamines in high yields (73–99%) within a short time, but 10 mol% of n-Bu4NBr should be added in the reactions of N-tosylaziridines with NiBr2·3H2O in order to obtain the high yields of corresponding β-bromoamines. Solvent played an important role in the reactions. The proper solvent for the reaction of NiCl2·6H2O was DMF, while NiBr2·3H2O or NiI2·6H2O proceeded well in 1,4-dioxane.