Asymmetric Direct Mannich Reaction Of Catalyzed By Novel Homobimetallic Nickel Complex

The resulting of the asymmetric Mannich reaction??amino carbonyl compounds are useful pharmaceutical intermediates,which can be converted into many natural products with biological activity.Thus,intensive efforts have been devoted to the development of efficient practical catalytic asymmetric direct Mannich reactions with metal catalysts or organicatalysts.Herein,we present a highly enantioselective direct Mannich reaction of malonates with N-tosyl aryl imines catalyzed by a novel dinuclear Ni complex with a 0.1–0.05 mol%catalyst loading on a 5–50mmol scale under mild reaction conditions.In addition,the N-Ts-?-amino esterswereeasilytransformedintothecorresponding N-tosylaziridine-2,2-dicarboxylates in high yields?up to 94%?and enantioselectivities?up to 96%?via a single step,which is a versatile building block in organic synthesis.At the same time,On the basis of control experiments and the ESI-MS analysis,we speculated that the Ni₂/L4 complex would be the active species.And the geometry of Ni₂/L4optimized by DFT is shown.