A mild and general method for preparation of α-glycosyl chlorides

Resolving the α-glycosidic linkage of arginine-rhamnosylated translation elongation factor P triggers generation of the first ArgRha specific antibody

“…3b): glycosyl chloride 3 in the desired configuration was obtained using well established procedures (85% yield). 25,26 Subsequently, 3 was treated with potassium thiocyanate (KSCN) and tetrabutylammonium hydrogen iodide (TBAI) in anhydrous acetonitrile to get glycosyl isothiocyanate 4 (70% yield). 27 Next, glycosyl thiourea 5 was prepared via ammoniation of 4 in tetrahydrofuran (99% yield).…”

Modulating glycosylation with exogenous nucleophiles: an overview

“…In a Koenig-Knorr glycosylation, Chang noted that the contamination of DMF increased the α-selectivity of the reaction. 55 Such findings initiated the exploration on the use of DMF nucleophile for modulated glycosylation. 45 A general DMF-modulated glycosylation procedure includes pre-activation of a glycosyl donor in the presence of DMF to form α/β-glycosyl imidinium adducts.…”

Gold-catalyzed synthesis of α-D-glucosides using an o-ethynylphenyl β-D-1-thioglucoside donor

“…[1, 2] Glycosylation reactions often involve oxocarbenium intermediates, which frequently result in the formation of anomeric mixtures of low to moderate selectivities (Scheme 1a). Previous achievements in selective construction of 1,2- cis glycosidic bond entail employing donor directing groups,[3–9] harnessing different reactivities of equilibrating donor anomers,[10–12] or exploiting conformational preferences of the reactive intermediates to minimize the formation of undesirable anomers (Scheme 1b). [13–16] Notwithstanding, these methods still rely on specific structural features of the donor molecule and, therefore, often fall short in generality.…”