Abstract
A family of complexes of the formula trans-[RuCl2(L)(R-pybox)] (R-pybox = (S,S)-iPr-pybox, (R,R)-Ph-pybox, L = monodentate phosphonite, PPh(OR)2, and phosphinite, L = PPh2(OR), ligands) were screened in the catalytic asymmetric transfer hydrogenation of acetophenone, observing a strong influence of the nature of both the R-pybox substituents and the L ligand in the process. The best results were obtained with complex trans-[RuCl2{PPh2(OEt)}{(R,R)-Ph-pybox}] (2c), which provided high conversion and enantioselectivity (up to 96% enantiomeric excess, e.e.) for the reduction of a variety of aromatic ketones, affording the (S)-benzylalcohols.
Highlights
Asymmetric transfer hydrogenation (ATH) of prochiral ketones catalyzed by transition metal complexes, displaying well designed chiral ligands, is currently recognized as a powerful and versatile tool to access enantiopure alcohols [1,2,3,4,5,6,7,8,9,10,11,12,13]
We have made some contributions in this field, on the synthesis and catalytic activity of group 8 metal complexes based on enantiopure N,N,N-ligands, lacking the N-H functionality
Continuing our studies on the ATH of ketones using ruthenium(II) complexes, containing pybox derivatives as the chiral auxiliary and phosphane/phosphite as the achiral phosphorous ligand, we reported the ATH reaction of aryl ketones catalyzed by ruthenium complexes trans-[RuCl2 (L){(S,S)i Pr-pybox}] and trans-[RuCl (L){(R,R)-Ph-pybox}], containing monodentate phosphonite (L = PPh(OR) )
Summary
Asymmetric transfer hydrogenation (ATH) of prochiral ketones catalyzed by transition metal complexes, displaying well designed chiral ligands, is currently recognized as a powerful and versatile tool to access enantiopure alcohols [1,2,3,4,5,6,7,8,9,10,11,12,13]. In this area, it must be mentioned that the studies focused on the asymmetric transfer hydrogenation (ATH) of ketones using ruthenium(II) complexes bearing PPh3 and enantiopure C2 or C1 symmetry N,N,N-donor ligands with NH functionality (see Figure 1A–E). We have made some contributions in this field, on the synthesis and catalytic activity of group 8 metal complexes based on enantiopure N,N,N-ligands, lacking the N-H functionality
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
