Three-Hindered Quadrant Phosphine Ligands with an Aromatic Ring Backbone for the Rhodium-Catalyzed Asymmetric Hydrogenation of Functionalized Alkenes
摘要:
The three-hindered quadrant phosphine ligands (R)-1-tert-butylmethylphosphino-2-(di-tert-butylphosphino)benzene ((R)-3H-BenzP*) and (R)-2-tert-butylmethylphosphino-3-(di-tert-butylphosphino)quinoxaline ((R)-3H-QuinoxP*) exhibited good to excellent enantioselectivities in the rhodium-catalyzed asymmetric hydrogenation of selected dehydroamino acid derivatives, enamides, and ethenephosphonates.
The three-hindered quadrant phosphine ligands (R)-1-tert-butylmethylphosphino-2-(di-tert-butylphosphino)benzene ((R)-3H-BenzP*) and (R)-2-tert-butylmethylphosphino-3-(di-tert-butylphosphino)quinoxaline ((R)-3H-QuinoxP*) exhibited good to excellent enantioselectivities in the rhodium-catalyzed asymmetric hydrogenation of selected dehydroamino acid derivatives, enamides, and ethenephosphonates.
A new and convenient approach for the synthesis of P-stereogenic intermediates bearing a tert-butyl(methyl)phosphino group
bearing a tert -butyl(methyl)phosphino group are important for the preparation of several commonly used diphosphine ligands. However, previously reported synthetic methods used hazardous starting materials and are difficult to operate. In order to overcome these limitations, a new and convenient synthesis for a number of P-stereogenic intermediates possessing a tert -butyl(methyl)phosphino group has