Os(II) Pincer Complex for Asymmetric H2 and Transfer Hydrogenation

Significance Catalytic asymmetric H 2 and transfer hydrogenation (TH) methods using Ru, Rh, and Ir complexes are well known. The authors have previously shown that several Os complexes display comparable activities compared to related Ru-based catalysts in TH of ketones ( Chem. Eur. J. 2008 , 14 , 2557). In the present work, isolation of the first CNN Os pincer complexes and their application in hydrogenation reactions are reported. Notably, these catalysts display tremendous levels of activity with loadings as low as 0.001 mol% and TOF of ˜10 5 h -¹ .