Cobalt-catalyzed hydrogenation of β-enamino esters using an internal mixture of bidentate and monodentate ligands

• A new catalytic system of cobalt has been prepared using a mixture of chiral and achiral ligands.
• This work is the first report in the hydrogenation of β-enamine esters using cobalt.
• The catalytic system afforded good yield and moderate enantioselectivity.
• Asymmetric amplification was found when using a non-chiral monodentate ligand in combination with the (R)-BINAP ligand.

Different β-amino esters have been obtained in good yields by means of octacarbonyldicobalt-catalyzed hydrogenation of β-enamine esters in the presence of mixture of a bidentate phosphine chiral (R-BINAP) and a monodentate phosphine achiral (PPh3). Likewise, a non-symmetric Co/BINAP/PPh3 complex was isolated. This new compound was used in the hydrogenation reaction under different conditions and the results suggest that this heterocombination could be responsible for improving enantiomeric excess in the reduction products.

Different β-amino esters have been obtained in good yields by means of octacarbonyldicobalt-catalyzed hydrogenation of β-enamine esters in the presence of mixture of a bidentate phosphine chiral (R-BINAP) and a monodentate phosphine achiral (PPh3).Figure optionsDownload as PowerPoint slide