Active catalysts for stereoselective ring-opening reactions

Abstract From the Canadian patent

A method for making a chiral transition metal-ligand catalyst complex that is active in catalyzing stereoselective ring opening reactions includes contacting an asymmetric tetradentate ligand in an excess of a Bronsted acid, with a salt of a first row transition metal wherein the acidity of the , conjugate acid of the salt is the same as or less than the acidity of the Bronsted acid, under conditions effective to allow formation of the active chiral transition metal-ligand catalyst complex and forming a solution of the , complex in a water-miscible protic solvent from which the active complex can be precipitated by the addition of water and adding water to the solution to precipitate …