Novel chiral dendritic diphosphine ligands for Rh(I)-catalyzed asymmetric hydrogenation : remarkable structural effects on catalytic properties

摘要

A series of dendritic ligands with a chiral diphosphine located at the focal point have been synthesized through coupling of pyrphos 2 with Fréchet-type polyether dendron 3. The relationship between the primary structure of the dendrimer and its catalytic properties was established in the Rh-catalyzed asymmetric hydrogenation of α-acetamido cinnamic acid 4. A remarkable structural effect on catalytic activity was observed.