A De Novo Route to 3,6-Dideoxy Sugars

Abstract

We report the de novo asymmetric synthesis of the 3,6-dideoxy sugars abequose, paratose, and tyvelose from 2acetylfuran. Conversion of this readily available ketone to a pyranone derivative was followed by transformation to either an αor βglycoside via diasteroselective acylation. Michael addition at C2 controlled primarily by the C1 configuration in the glycoside produced 3,6-dideoxy-4-keto sugars, which could be reduced and converted to either fully deprotected monosaccharides or to immediate precursors of glycosyl donors.

Visible-Light-Promoted Desulfurization to Synthesize Deoxyglycosides

“…Methyl 2,3,6-Tri-O-benzoyl-4-deoxy-α-D-galactopyranoside (8). 31 Methyl 4-S-acetyl-2,3,6-tri-O-benzoyl-α-D-galactopyranoside 7 was synthesized in light of the reported ref 31.…”

“…The synthesis of deoxyglycosides, especially 2-deoxyglycosides, has been identified as one of the most important areas in carbohydrate chemistry since deoxysugar fragments are frequently present in many biologically active natural products. − Deoxysugar synthesis methods typically involve the modification of hydroxyl groups and subsequent reduction. The reported methods involved dehalogenation, − desulfurization, − reduction of glycals, − and reduction of glycosides with thiocarbonyl groups − and sulfonates, − where Raney nickel or Pd-catalyzed hydrogenation is the most commonly used means.…”

De novoasymmetric Achmatowicz approach to oligosaccharide natural products

“…While the comparison of these de novo routes to traditional carbohydrate routes is difficult, these de novo routes have a clear advantage in terms of d -/ l -sugar variability and for rare sugars. 32 In addition, when these de novo routes are applied to oligosaccharide targets, they often are executed with the use of fewer protecting groups and sometimes no protecting groups. In our view, the best metric for this evaluation is in terms of synthetic utility and variability, which is highlighted in the following synthetic endeavors (Scheme 4–21).…”

TsOH-catalyzed acyl migration reaction of the Bz-group: innovative assembly of various building blocks for the synthesis of saccharides

“…Carbohydrates are an interesting class of biomolecules that play essential roles in various biological processes and are exploited as scaffolds for the generation of different bioactive compounds. 1 As the most abundant natural resource, they have found widespread application in the construction of pharmaceuticals, polymers, oligosaccharides, and glycoconjugates. 2 The laboratory synthesis of oligosaccharides and glycoconjugates has been pursued for decades as a means to access new therapeutic agents and probes with biological function.…”