WebJun 14, 2024 · Based on their mechanistic studies, they proposed that chiral Brønsted acid catalyst 6 stimulated both the acceptor and the OTCA donor promoting an S N 2-type reaction with R -enantiomer of the racemic mixture of secondary alcohols to form a chiral transition state like 11, which accounts for the high 1,2- trans selectivity. SCHEME 3 … WebJul 19, 2024 · Abstract. Herein, we reported on a highly efficient glycosylation reaction comprising two chronological meticulously designed catalytic cycles: (1) rhodium-catalyzed formation of sulfonium ylide and (2) Brønsted acid-catalyzed formation of sulfonium ion. This protocol highlighted an effective and robust tactic to prepare a glycosyl sulfonium ...
Kinetic Resolution of Azaarylethynyl Tertiary Alcohols by Chiral ...
WebT Kimura, M Sekine, D Takahashi, K Toshima, Chiral Brønsted acid mediated glycosylation with recognition of alcohol chirality. Angew Chem Int Ed Engl 52, … WebOct 13, 2014 · The stereochemical outcome of glycosylation reactions of 2-deoxy-sugar trichloroacetimidates promoted by chiral Brønsted acids is shown to be dependent on both the chirality of the catalyst... how do i open a dbf file in excel
Chiral Brønsted acid mediated glycosylation with recognition of …
WebThe use of a chiral Brønsted acid catalyst for the activation of trichloroacetimidate glycosyl donors influences the stereochemical outcome of glycosylation processes in … WebFeb 10, 2024 · A new type of chiral super Brønsted C–H acids, BINOL-derived phosphoryl bis((trifluoromethyl)sulfonyl) methanes (BPTMs), were developed. As compared to widely utilized BINOL-derived chiral phosphoric acids (BPAs) and N-triflyl phosphoramides (NTPAs), BPTMs displayed much higher Brønsted acidity, resulting in dramatically … WebMar 3, 2010 · The use of a chiral Brønsted acid catalyst for the activation of trichloroacetimidate glycosyl donors has been demonstrated for the first time, hinting that … how do i open a dbf file