Fig. 6. The catalytic cycle of the investigated transfer hydrogenation of imines is shown. Therefore, all possible rate determining steps are shown. The steps which could be neglected as rate-determining steps by experiments or calculations are shown in green, while the potential bottlenecks are shown in red. Finally, we assume a delicate equilibrium between the E- to Z-isomerization and the ternary complex formation to be the rate-determining step.