Hydrated nickel (II) halides mediated ring opening reaction with N-tosylaziridines

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.