Design And Synthesis Of A Novel Axial Bisphosphine Ligand Induced By Central Chirality, And Their Applications In Catalytic Asymmetric Reaction

Chiral bisphosphine ligands are widely used in asymmetic catalysis,especially in the area of asymmetric hydrogenation reactions.However,tedious resolution procedure always puzzles the synthesis of many chiral phosphine ligands.It is of great importance to develop novel chiral bisphosphine ligands through chirality transformation,which might avoid the resolution procedure.This thesis mainly contains the synthesis of novel 4,4'-substituted chiral axially bisphosphine ligands induced by central chirality from easily obtained,commercially available starting materials,The effectiveness of this new chiral ligand was demonstrated by Ru-catalyzed asymmetric hydrogenation of challengingβ-aryl substitutedβ-ketoesters. Excellent reactivity and high enantioselcetivity were obtained for the tested substrates. The ligand also showed good enantioselectivity in Rh-catalyzed hydrogenation of someα-dehydroamino acid derivatives comparing with the results obtained by BINAP.The main research work was summarized as follow:1 Chiral bisphosphine ligand was designed and synthesized,the method precluded the tedious resolution procedures usually required for preparing enantiomerically pure diphosphine ligands2 The reaction conditions of the asymmetric hydrogenation ofβ-ketoesters were optimized,the factors of enantioselectivity in asymmetric hydrogenation reaction were investigated.