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

Anefficient Ni-(S,S)-Ph-BPEcomplex that catalyzed asymmetric hydrogenation of cyclic N-acyl hydrazones has been developed to produce variouschiral cyclic hydrazines in high yields with excellent enantioselectivitiesof up to >99% enantiomeric excess. Moreover, the hydrogenationcannot only proceed smoothly on a gram scale under lower catalyst loading(S/C = 3000) without any decrease of enantioselectivity but can alsobe applied to the asymmetric synthesis of a RIP-1 kinase inhibitor.