A borinic acid derived catalyst enables regioselective and β-selective reactions of 2-deoxy- and 2,6-dideoxyglycosyl chloride donors with pyranoside-derived acceptors having unprotected cis-1,2- and 1,3-diol groups. The use of catalysis to promote a β-selective pathway by enhancement of acceptor nucleophilicity constitutes a distinct approach from previous work, which has been aimed at modulating donor reactivity by variation of protective and/or leaving groups.
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http://dx.doi.org/10.1021/ol501711v | DOI Listing |
Angew Chem Int Ed Engl
May 2024
Abteilung Chemische Biologie, Max Planck Institut für Molekulare Physiologie, Otto-Hahn-Straße 11, 44227, Dortmund, Germany.
Herein, we demonstrate the robustness of a synergistic chiral Pd/organoboron system in tackling a challenging suite of site-, regio-, enantio- and diastereoselectivity issues across a considerable palette of biologically relevant carbohydrate polyols, when prochiral alkoxyallenes were employed as electrophiles. In view of the burgeoning role of noncovalent interactions (NCIs) in stereoselective carbohydrate synthesis, our mechanistic experiments and DFT modeling of the reaction path unexpectedly revealed that NCIs such as hydrogen bonding and CH-π interactions between the resting states of the Pd-π-allyl complex and the borinate saccharide are critically involved in the stereoselectivity control. Our strategy thus illuminates the untapped potential of harnessing NCIs in the context of transition metal catalysis to tackle stereoselectivity challenges in carbohydrate functionalization.
View Article and Find Full Text PDFOrg Lett
July 2014
Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, ON M5S 3H6, Canada.
A borinic acid derived catalyst enables regioselective and β-selective reactions of 2-deoxy- and 2,6-dideoxyglycosyl chloride donors with pyranoside-derived acceptors having unprotected cis-1,2- and 1,3-diol groups. The use of catalysis to promote a β-selective pathway by enhancement of acceptor nucleophilicity constitutes a distinct approach from previous work, which has been aimed at modulating donor reactivity by variation of protective and/or leaving groups.
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