Enantioselective Desymmetrization of 2-Aryl-1,3-propanediols by Direct O-Alkylation with a Rationally Designed Chiral Hemiboronic Acid Catalyst That Mitigates Substrate Conformational Poisoning
Carl D. Estrada, Hwee Ting Ang, Kim-Marie Vetter, Ashley A. Ponich and Dennis G. Hall*
*Department of Chemistry, Centennial Centre for Interdisciplinary Science, University of Alberta, Edmonton, Alberta, Canada, T6G 2G2, Email: dennis.hallualberta.ca
C. D. Estrada, H. T. Ang, K.-M. Vetter, A. A. Ponich, D. G. Hall, J. Am. Chem. Soc., 2021, 143, 4162-4167.
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A bench-stable chiral 9-hydroxy-9,10-boroxarophenanthrene catalyst is applied in a highly enantioselective desymmetrization of 2-aryl-1,3-diols using benzylic electrophiles under operationally simple, ambient conditions. Nucleophilic activation and discrimination of the enantiotopic hydroxy groups on the diol substrate occurs via a defined chairlike six-membered anionic complex.
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stereochemical model for monobenzylation