Homogeneous enantioselective catalysis in a continuous-flow microreactor: Highly enantioselective borohydride reduction of Ketones catalyzed by optically active cobalt complexes

Highly enantioselective homogeneous catalysis under continuous-flow conditions was established for the cobalt-catalyzed borohydride reduction of tetralone derivatives. A microreactor allowed higher reaction temperature with the residence time of 12 min than the corresponding batch system to maintain enantioselectivity as well as reactivity. The present system was directly applied to gram-scale synthesis to afford the reduced product with 92% ee.