Utilization of Cooperative Ni Catalyst for Selective Transfer Hydrogenation of N-Heteroarenes with Minimal Hydrogen Surrogate

Herein, an air-stable cooperative Ni(II)-NNN catalyst ( 1 ) bearing a bis(2-hydroxy pyridine) ligand was synthesized for the selective transfer hydrogenation of quinoline derivatives to 1,2,3,4-tetrahydro derivatives utilizing minimal loading of Me 2 NHBH 3 as a hydrogen surrogate via a borylated product intermediate. Mechanistic studies include the identification of catalytically relevant deprotonated intermediate 1a, which sheds light on the hydride and proton transfer to the quinoline derivatives via the participation of the functionalized protic ligand arm.