348631-15-2Relevant academic research and scientific papers
Mapping the Relationship between Glycosyl Acceptor Reactivity and Glycosylation Stereoselectivity
van der Vorm, Stefan,van Hengst, Jacob M. A.,Bakker, Marloes,Overkleeft, Herman S.,van der Marel, Gijsbert A.,Codée, Jeroen D. C.
supporting information, p. 8240 - 8244 (2018/05/03)
The reactivity of both coupling partners—the glycosyl donor and acceptor—is decisive for the outcome of a glycosylation reaction, in terms of both yield and stereoselectivity. Where the reactivity of glycosyl donors is well understood and can be controlled through manipulation of the functional/protecting-group pattern, the reactivity of glycosyl acceptor alcohols is poorly understood. We here present an operationally simple system to gauge glycosyl acceptor reactivity, which employs two conformationally locked donors with stereoselectivity that critically depends on the reactivity of the nucleophile. A wide array of acceptors was screened and their structure–reactivity/stereoselectivity relationships established. By systematically varying the protecting groups, the reactivity of glycosyl acceptors can be adjusted to attain stereoselective cis-glucosylations.
Synthesis of methyl α-D-glucopyranosyl-(1→4)-α-D-galactopyranoside and methyl α-D-xylo-hex-4-ulopyranosyl-(1→4)-α-D-galactopyranoside
Liotta, Louis J.,Capotosto, Rita D.,Garbitt, Rachel A.,Horan, Brian M.,Kelly, Pamela J.,Koleros, Andrew P.,Brouillette, Lisa M.,Kuhn, Amy M.,Targontsidis, Sonia
, p. 247 - 253 (2007/10/03)
The syntheses of methyl α-D-glucopyranosyl-(1→4)-α-D-galactopyranoside (1) and methyl α-D-xylo-hex-4-ulopyranosyl-(1→4)-α-D-galactopyranoside (4) are reported. The keto-disaccharide 4 is of interest in our design, synthesis, and study of pectate lyase inhibitors. The key step in the syntheses was the high-yielding, stereospecific formation of methyl 4,6-O-benzylidene-2′,3′-di-O-benzyl-α-D-glucopyranosyl- (1→4)-2,3,6-tri-O-benzyl-α-D-galactopyranoside (15), which was accomplished by reacting 2,3-di-O-benzyl-4,6-O-benzylidene-D-glucopyranosyl trichloroacetimidate (10) with methyl 2,3,6-tri-O-benzyl-α-D-galactopyranoside (14) in the presence of a catalytic amount of tert-butyldimethylsilyl trifluoromethane sulfonate (TMSOTF). Compound 15 was either hydrogenolyzed to yield disaccharide 1 or treated with NaBH3CN-HCl in 1:1 tetrahydrofuran-ether to yield methyl 2,3,6-tri-O-benzyl-α-D-glucopyranosyl-(1→4)-2,3,6-tri-O-benzyl- α-D-galactopyranoside (2). The free 4′-OH of compound 2 was oxidized to a carbonyl group by a Swern oxidation, and the protecting groups were removed by hydrogenolysis to yield keto-disaccharide 4. These synthetic pathways were simple, yet high yielding.
