Catalytic Enantioselective Amination of Enol Silyl Ethers Using a Chiral Paddle-Wheel Diruthenium Complex

A chiral paddle-wheel dinuclear ruthenium catalyst was applied to a catalytic asymmetric nitrene-transfer reaction with enol silyl ethers. The ruthenium catalyst was applicable to aliphatic enol silyl ethers as well as aryl-containing enol silyl ethers. The substrate scope of the ruthenium catalyst was superior to that of analogous chiral paddle-wheel rhodium catalysts. α-Amino ketones derived from aliphatic substrates were obtained in up to 97% ee with the ruthenium catalyst, while analogous rhodium catalysts resulted in only moderate enantioselectivity.