Asymmetric hydroformylation is one of the most challenging transformations because it requires both high enantioselectivities and regioselectivies with high activity. Also, there are few effective ways to prepare chiral ligands. To address these challenges, a series of new diphosphite ligands have been developed in our lab. These new ligands have been investigated in rhodium-catalyzed asymmetric hydroformylation of vinyl acetate and its derivatives. They provide moderate enantioselectivities (up to 80 % ee) and excellent regioselectivies (b/l up to 98/2) in rhodium-catalyzed asymmetric hydroformylations of vinyl acetate and its derivatives.
Although numerous efficient chiral ligands have been developed for asymmetric hydrogenation, there is no universal ligand which can be applied in all prochiral substrates with high enantioselectivity. To expand the substrate scope, the development of new chiral ligands is highly desirable. A chiral diphosphine ligand has been designed and synthesized. This new ligand bearing chiral C3-biphenyl backbone provides excellent enantioselectivies in rhodium-catalyzed asymmetric hydrogenation of á-dehydroamino acid esters and itaconate.