Development In Phosphorus Ligands And Their Applications In Rhodium Catalyzed Reactions

Transition-metal-catalyzed reactions have become powerful tools in the production of pharmaceuticals and fine chemicals. In the past decades, asymmetric catalysis, especially chiral rhodium catalysts, hold an increasing role of efficiently building up chirality. In this dissertation, we will focus on the development of several rhodium phosphorus catalysts and their applications in hydroformylation and asymmetric hydrogenation reactions. Chapter I outlined the development of a new family of sterrically rigid hybrid phosphine-phosphoramidite ligands. The new catalyst system shows excellent compatibility versus styrene, vinyl acetate, allyl cyanide and their derivatives. The relationship between the enantioselectivity and the substituent on ligands is investigated by systematic variation on the ligand structures. In chapter II, further application of phosphine-phosphoramidite ligands in asymmetric hydroformylation of N-allylamides and N-allylsulfonamides provides a new approach to chiral [beta]2-amino aldehydes, acids, and alcohols for pharmaceutical and synthetic chemistry. Up to 99% ee and 9700 turnovers stands as the best result achieved in this type of hydroformylation reaction. Chapter III focuses on the synthesis of a series of aryl substituted dihydropyrroles via this hydroformylation. The significant improvement in reactivity and chemoselectivity suggests a potential application in building large heterocycles in an atom efficient fashion. In chapter IV, I report a successful monodentate phosphoramidite ligand for the catalytic asymmetric hydrogenation of dehydroamino esters. The easy modulared structure allowed us to further expand the scope of the ligand.