Enantioselective Synthesis of Chiral Cyclic Hydrazines by Ni-Catalyzed Asymmetric Hydrogenation.

An efficient Ni-( S , S )-Ph-BPE complex that catalyzed asymmetric hydrogenation of cyclic N -acyl hydrazones has been developed to produce various chiral cyclic hydrazines in high yields with excellent enantioselectivities of up to >99% enantiomeric excess. Moreover, the hydrogenation can not only proceed smoothly on a gram scale under lower catalyst loading (S/C = 3000) without any decrease of enantioselectivity but can also be applied to the asymmetric synthesis of a RIP-1 kinase inhibitor.