Asymmetric transfer hydrogenation of ketones by N,N-containing quinazoline-based ruthenium(II) complexes
•This is the first example of chiral amino Quinazoline-based ruthenium complex.•The related complexes were used in asymmetric transfer hydrogenation reaction.•The catalytic activity of these complexes were compared according to the chirality environment•These complexes are advantageous as they are air stable and derived from amino acids.
The novel set of quinazoline-based chiral ligands was synthesized starting from optically pure amino acids. Coordination with RuCl2(PPh3)dppb gave ruthenium(II) N-heterocyclic complexes 4b–d. The structure of complex 4b was fully illuminated by X-ray crystallography. The steric environment of these chiral ruthenium complexes 4b–d was evaluated in asymmetric transfer hydrogenation (ATH) of prochiral ketones in the presence of NaOiPr by using 2-propanol as the hydrogen source and solvent. The resultant catalytic system can achieve very good enantioselectivities (up to 91%) and high yields (up to 99%).
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Journal: Catalysis Communications - Volume 74, 10 January 2016, Pages 122–125