Nickel-Catalyzed Asymmetric Hydrogenation of Hydrazones

An efficient nickel-catalyzed asymmetric hydrogenation of hydrazones to chiral hydrazines has been realized with up to 99 % yield and 99.4 : 0.6 er. Deuterium labelling experiments indicated that the hydrazone substrates undergo imine-enamine tautomerization in the mixed solvents. Studies on the effects of acids revealed that the required acid assistance promoted the dissociation of the active nickel catalyst in the catalytic cycle.

Automated summary

An efficient nickel-catalyzed asymmetric hydrogenation of hydrazones to chiral hydrazines has been achieved with high yields and enantiomeric excess. Deuterium labelling experiments showed tautomerization of hydrazone substrates in mixed solvents, while the presence of acids promoted the dissociation of the active nickel catalyst in the catalytic cycle.