Synthesis of derivatives of the trisaccharide repeating unit of the O-specific polysaccharide from Salmonella anatum

Reagent switchable stereoselective β(1,2) mannoside mannosylation: OH-2 of mannose is a privileged acceptor

“…1) involve the synthesis of a b-glucoside, followed by inversion of C-2 configuration either by a nucleophilic displacement 4, 5 or an oxidation-reduction procedure. 6, 7 Intramolecular aglycon delivery has also been developed by several groups as a method for the synthesis of 1,2-cis glycosides and has been applied to the synthesis of b-mannosides. 8-14 Fig.…”

Strategies of Synthetic Methodologies for Constructing β-Mannosidic Linkage

“…This led Lindberg to synthesize β-mannosides [126]. Various oligosaccharides were obtained by glucosylation, selective deprotection of the 2-O, oxidation and reduction to give β -mannoside oligosaccharides [125][126][127][128][129][130][131][132][133][134][135][136][137][138]. The Ac 2 O/DMSO was frequently used as oxidant and sodium borohydride or lithium-tri-sec-butylbromide as reducing agents.…”

Epimerization of Glycal Derivatives by a Cyclopentadienylruthenium Catalyst: Application to Metalloenzymatic DYKAT

“…Such molecules are synthetically accessible through stereocontrolled de novo synthesis1, 2 or modifications of readily available carbohydrates 3. 4 The latter methodology frequently involves stereochemical inversions of secondary alcohols, which regularly follow two‐step procedures: triflation followed by nucleophilic displacement or oxidation and subsequent stereoselective reduction 5–7. An alternative method would be to use a dynamic kinetic asymmetric transformation (DYKAT) approach utilizing a redox epimerization catalyst to epimerize the alcohol and subsequently trap the inverted alcohol in a transesterification reaction catalyzed by a stereoselective enzyme (Figure 1).…”