title: Synthesis of the C-linked disaccharide alpha-D-Man-(1-->4)-D-Man employing a SmI(2)-mediated C-glycosylation step: en route to cyclic C-oligosaccharides.
abstract: Investigations are reported on the assembly of the C-linked disaccharide alpha-D-Man-(1-->4)-D-Man, representing the first steps in our projected synthesis of a cyclic C-oligomer containing repeating units of this C-dimer. The key step in this synthesis uses a SmI(2)-mediated coupling of 2,3,4,6-tetra-O-benzyl-alpha-D-mannopyranosyl 2'-pyridyl sulfone with a C4-formyl branched mannopyranoside unit, affording the C-disaccharide derivative with complete stereocontrol at the two new stereogenic centers. Subsequently, a modified tin hydride based deoxygenation produced the target carbohydrate analogue. The synthesis of the C4-formyl monosaccharide makes use of a stereoselective radical-based allylation followed by double bond migration and ozonolysis.
authors.affiliation: Department of Chemistry, University of Aarhus, Langelandsgade 140, 8000 Aarhus C, Denmark.
authors.forename: Lise Munch
authors.initials: LM
authors.lastname: Mikkelsen
authors.forename: Troels
authors.initials: T
authors.lastname: Skrydstrup
mesh_terms: D002384:Catalysis; D020650:Combinatorial Chemistry Techniques; D004187:Disaccharides / Q000138:chemical synthesis*; D006031:Glycosylation; D007202:Indicators and Reagents; D007454:Iodides / Q000737:chemistry; D008362:Mannosides / Q000138:chemical synthesis*; D015394:Molecular Structure; D019906:Nuclear Magnetic Resonance, Biomolecular; D009844:Oligosaccharides / Q000138:chemical synthesis*; D010126:Ozone / Q000737:chemistry; D012493:Samarium / Q000737:chemistry; D013237:Stereoisomerism
chemical_list: D004187:Disaccharides; D007202:Indicators and Reagents; D007454:Iodides; D008362:Mannosides; D009844:Oligosaccharides; C476281:alpha-D-Man-(1-4)-D-Man; D012493:Samarium; D010126:Ozone; C409809:samarium diiodide