Aminophosphines with Axial Chirality for Asymmetric Catalysis

Abstract

The utility of phosphine-containing chiral ligands has been well established and a new type of axially chiral C(aryl)-N(amine) ligand is described. The authors use a simple procedure to access a family of these axially chiral ligands in racemic form. Next, they expertly employ a palladium source with existing chirality to generate dia­stereomers which are separable on a simple silica gel column. The palladium is then titrated off with ethylene diamine to yield the ligands optically resolved, both with >99% ee. Application of the ligands in the palladium-catalyzed allylic alkylation was then employed and all ligands gave ee values ≥89%.