Enantioselective Hydrogenation of the Tetrasubstituted C=C Bond of Enamides Catalyzed by a Ruthenium Catalyst Generatedin situ

Abstract

The enantioselective hydrogenation of enamides bearing an endocyclic tetrasubstituted carbon-carbon double bond has been performed in the presence of ruthenium catalyst precursors prepared from Ru(cod)(methallyl)2, Duphos, or BPE as optically active ligand and HBF4. This promising catalytic system makes possible the selective cis-hydrogenation with satisfactory enantioselectivities (up to 72% ee) for this type of tetrasubstituted double bonds.