Bifunctional Triflylamide-Tethered Cp′Rh and Cp′Ir Complexes: A New Entry for Asymmetric Hydrogenation Catalysts

A series of triflylamide-tethered Cp′Rh and Cp′Ir complexes, [η⁵:η¹-(CH₃)₄C₅(CH₂)_nNTf]M (M = Rh, Ir, n = 2−4), have been newly prepared and their three-legged piano-stool structure has been characterized. The tethered complexes having the (R,R)-MsDPEN ligand have been found to promote asymmetric hydrogenation of acetophenone, which indicates that the introduction of a suitable triflylamide tether unit changes their catalytic function from transfer hydrogenation to hydrogenation.