Synthesis and Application of Hexamethyl-1,1'-spirobiindane-Based Phosphine-Oxazoline Ligands in Ni-Catalyzed Asymmetric Arylation of Cyclic Aldimines.

With the vastly increasing applications of chiral phosphine-oxazoline (PHOX) hybrid ligands in various transition-metal-catalyzed reactions, novel PHOX ligands bearing innovative backbones are highly valuable and in great demand. This study describes the development of a new type of chiral PHOX ligands based on a hexamethyl-1,1'-spirobiindane scaffold and incorporating both a phosphine and an oxazoline moiety. The optimal ligand provided high yields and excellent enantioselectivities for the Ni-catalyzed asymmetric arylation of cyclic N-sulfonyl imines with arylboronic acids leading to chiral amines.