Asymmetric Transfer Hydrogenation of 2,3-Disubstituted Flavanones through Dynamic Kinetic Resolution Enabled by Retro-Oxa-Michael Addition: Construction of Three Contiguous Stereogenic Centers
Qing-Xian Xie, Li-Xia Liu, Zhou-Hao Zhu, Chang-Bin Yu* and Yong-Gui Zhou*
*State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, PR China, Email: cbyudicp.ac.cn, ygzhoudicp.ac.cn
Q.-X. Xie, L-X. Liu, Z.-H. Zhu, C.-B. Yu, Y.-G. Zhou, J. Org. Chem., 2022, 87, 7521-7530.
A Ru-catalyzed asymmetric transfer hydrogenation of 2,3-disubstituted flavanones provides chiral flavanols with three contiguous stereocenters with excellent ees and drs. The reaction proceeds via a base-catalyzed retro-oxa-Michael addition to racemize two stereogenic centers simultaneously in concert with a highly enantioselective ketone transfer hydrogenation step.
see article for more examples
proposed reaction pathway