Novel chiral C2-symmetric multidentate aminophosphine ligands for use in catalytic asymmetric reduction of ketones

A series of novel chiral C2-symmetric multidentate aminophosphine ligands have been successfully synthesized by Schiff-base condensation of bis(o-formylphenyl)phenylphosphane and easily available monoprotected (1R,2R)-diaminocyclohexane. The catalytic properties of these ligands were investigated in Ir-catalyzed asymmetric transfer hydrogenation of various aromatic ketones, giving the corresponding optical active alcohols with up to 98% conversion and good ee under mild reaction conditions.

Graphical abstractA series of novel chiral C2-symmetric multidentate aminophosphine ligands have been successfully synthesized by Schiff-base condensation of bis(o-formylphenyl)phenylphosphane and easily available monoprotected (1R,2R)-diaminocyclohexane. The catalytic properties of these ligands were investigated in Ir-catalyzed asymmetric transfer hydrogenation of various aromatic ketones, giving the corresponding optical active alcohols with up to 98% conversion and good ee under mild reaction conditions.Figure optionsDownload full-size imageDownload as PowerPoint slide