Facile synthesis of aminooxy glycosides by gold(III)-catalyzed glycosidation

O-Glycosylation Enabled by N-(Glycosyloxy)acetamides

“…The crude product was purified by flash column chromatography (petroleum ether:ethyl acetate = 3:1, v/v) to afford 4 as a white solid (0.68 g, 81%). The 1 H NMR and 13 C NMR data for 4 are in accordance with those reported previously …”

“…The same procedure for the synthesis of 19 was applied, yielding 25 (0.30 g, 82%) as a white solid. The 1 H NMR and 13 C NMR data for 25 are in accordance with those reported previously …”

“…To assess the feasibility of our idea, a systematic survey of substitution patterns on hydroxamate was carried out. For this purpose, galactoside 3 with a phthalimidyl group, galactoside 4 with a succinimidyl group, galactoside 5 with a N -methylacetamidyl group, and galactoside 7 with an acetamidyl group were readily prepared from galactosyl bromide 1 (Scheme ). With these glycosyl donors in hand, we evaluated the glycosylation reactions of glycosyl acceptor 8 with these donors under different conditions (Table , Tables S1 and S2 in Supporting Information).…”

Applications of alkyl orthoesters as valuable substrates in organic transformations, focusing on reaction media

“…In 2015, Rao et al employed propargyl 1,2-orthoesters (625) as key synthons and glycosyl donors for the synthesis of thiosaccharides and 1-thiotrehaloses (627) in a 1,2-trans diastereoselective form only via the glycosidation reaction [503][504][505][506][507][508][509] with glycosyl mercaptans (626), as glycosyl acceptor, using gold(III) bromide (AuBr 3 , 7 mol%) as catalyst in CH 2 Cl 2 at room temperature under argon atmosphere in excellent yields (83-94%) within 6 h (Scheme 190). 509 In 2015, Vadhadiya and Ramana reported the rst total synthesis of sinenside A.…”

Substoichiometric FeCl3 Activation of Propargyl Glycosides for the Synthesis of Disaccharides and Glycoconjugates

“…18 However, most of the methods for the activation of propargyl glycosides were limited to the use of toxic or noble catalysts such as Hg(OTf) 2 , AuCl 3 , AuBr 3 , or AuCl 3 with AgSbF 6 , which makes them difficult to be widely used in the synthesis of glycosides. [19][20][21][22][23][24][25][26][27] Beyond that, some reactions also depended on the use of 4 Å molecular sieves. Sureshkumar et al reported the AuBr 3 promoted glycosylation reaction between propargyl 1,2-orthoesters and various aglycones in the presence of 4 Å powdered molecular sieves and delivered the product in satisfactory yield.…”