Enantioselective Intermolecular Benzylic C–H Amination under Chiral Paddle-Wheel Diruthenium Catalysis

A catalytic asymmetric intermolecular benzylic C–H
amination
was achieved under paddle-wheel diruthenium catalysis. A chiral diruthenium
catalyst incorporating (S)-TPPTTL (tetraphenylphthaloyl-(S)-tert-leucine) ligand exhibited notable
enantioselectivity, and aminated products were obtained with up to
99% ee. Unique chemoselectivity of the chiral diruthenium catalyst
was also found for allylbenzene and alkyl-naphthalene substrates,
demonstrating the complementary synthetic utility of chiral paddle-wheel
Ru(II)–Ru(III) catalysts to Rh(II) counterparts.