Homogeneous Enantioselective Catalysis in a Continuous-Flow Microreactor: Highly Enantioselective Borohydride Reduction of Ketones Catalyzed by Optically Active Cobalt Complexes
† Department of Chemistry, Keio University, Hiyoshi, Kohoku-ku, Yokohama 223-8522, Japan
‡ Hitachi Research Laboratory, Hitachi, Ltd., 832-2 Horiguchi, Hitachinaka, Ibaraki 312-0034, Japan
§ Hitachi Plant Technologies, Ltd., 603 Kandatsu-machi, Tsuchiura, Ibaraki 300-0013, Japan
Org. Process Res. Dev., 2012, 16 (6), pp 1235–1240
DOI: 10.1021/op300061k
Abstract
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.
////////////Homogeneous Enantioselective Catalysis, Continuous-Flow Microreactor, Highly Enantioselective Borohydride, Reduction of Ketones Catalyzed, Optically Active Cobalt Complexes
