Asymmetric hydrogenation of alkenes with planar chiral 2-phosphino-1-aminoferrocene-iridium(I) complexes

The first highly enantioenriched and enantiopure planar chiral 2-phosphino-1-aminoferrocene ligands and their Ir(COD)BArF complexes are reported. The ligands display bidentate coordination behavior towards iridium, as indicated by trends in 31P and 1H NMR spectra of the phosphine moieties and the α to nitrogen substituents of the amines. All of the new complexes showed good reactivity as catalysts in promoting asymmetric hydrogenation of several prochiral alkenes, with enantioselectivities up to 92%. Iridium complexes of dimethylaminoferrocene derivatives containing P–Ar groups [PPh2 and P(o-tol)2] gave the highest levels of asymmetric induction.

Graphical abstract(1) Planar chiral 2-phosphino-1-aminoferrocenes, (2) bidentate aminophosphine ligands, (3) Ir(COD)BArF coordination complexes and (4) asymmetric hydrogenation of alkenes.Figure optionsDownload full-size imageDownload as PowerPoint slide