Diastereoselectivity and catalytic activity in ruthenium complexes chiral at the metal centre

• Diastereomerically pure ruthenium diamine diphosphine complexes were synthetized.
• CD-spectroscopy confirm the diastereoselective trans–cis isomerisation.
• A matching between the ligands were observed.
• The matching complexes are suitable for ATH of aryl ketones up to 99% e.e.
• The chirality of the metal centre defines the configuration of the products.

Cis-RuCl2(diphosphine)(CAMPY) complexes, chiral at the metal centre with matching or mismatching chiralities between diphosphine and CAMPY were prepared and the configuration at the metal was determined in solution by a complete set of NMR investigations; CAMPY is (R)-(−) or (S)-(+)-8-amino-5,6,7,8-tetrahydroquinoline. The complexes were used in ATH reactions of different aryl ketones with 2-propanol as hydrogen source. The effects of the chirality at the metal were studied and enantiomeric excesses up to 99% were obtained.

CD and NMR spectra show complete stereoselectivity of trans → cis transformation in [RuCl2(diphosphine)(CAMPY)] complexes. The chirality of ruthenium originates from the matching between the ligands’ chirality with d.e.% up to 99%. The optical purity of the metal centre is related to that of the ATH products of ketones.Figure optionsDownload as PowerPoint slide