Chiral Ferrocenylphosphines and their Use as Ligands for Transition Metal Complex Catalyzed Asymmetric Synthesis

Abstract

There has been intense interest and activity recently in asymmetric synthesis catalyzed by transition metal complexes with chiral ligands [1,2], This has resulted in so great success in asymmetric homogeneous hydrogenation by chiral phosphine-rhodium complexes as to produce α-amino acids with over 90% optical purity [3]. One of the most significant problems in studies on the catalytic asymmetric synthesis is how to develop a chiral ligand which will enable the catalyst for a given reaction to be as efficient in stereoselectivity as possible, and considerable efforts have been devoted to searching for new chiral phosphine ligands. These chiral phosphines may be classified into two classes: (A) phosphines bearing an asymmetric center at the phosphorus atom and (B) phosphines whose chirality is due to asymmetric carbons in groups bonded to phosphorus.