Iridium-catalyzed asymmetric hydrogenation of 3-substituted unsaturated oxindoles to prepare C3-mono substituted oxindoles

An efficient and enantioselective hydrogenation of 3-substituted unsaturated oxindoles has been developed by an iridium complex of tropos phosphine–oxazoline ligands. It is the first example to prepare chiral C3-mono substituted oxindoles via asymmetric catalysis. And the reaction provides instant access to this kind of compounds with excellent conversion and enantioselectivities (up to 93% ee).