Samarium‐Catalyzed Diastereoselective Double Addition of Phenylphosphine to Imines and Mechanistic Studies by DFT Calculations

Abstract

AbstractThe catalytic hydrophosphination of imines represents the most straightforward and atom‐economical strategy for the preparation of α‐aminophosphines, which are useful as biologically active molecules and ligands for catalysis. The first catalytic protocol for the rapid and high‐yielding hydrophosphination of common imines enabled by an ene–diamido samarium methoxide catalyst was developed. The reaction allowed the efficient and diastereoselective synthesis of various bis(α‐amino)phosphines through the double addition of PhPH2 to common imines. The catalytic reaction has a relatively wide substrate scope and offers high diastereoselectivities (up to 99:1 dr for meso products) and high yields (up to 97 %). DFT calculations disclosed an inner‐sphere mechanism involving unprecedented activation of a Sm−O bond by a phosphine and stabilization of the addition intermediates by the metal center.