ACTIVE CATALYSTS FOR STEREOSELECTIVE RING-OPENING REACTIONS

摘要

A method for making a chiral transition metal-ligand catalyst complex that i s active in catalyzing stereoselective ring opening reactions includes contacting an asymmetric tetradentate ligand, in an excess of a Bronsted aci d, 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 t he complex in a water-miscible, protic solvent from which the active complex ca n be precipitated by the addition of water and adding water to the solution to precipitate at least a portion of the complex.