title: Carbene-mediated functionalization of the anomeric C-H bond of carbohydrates: scope and limitations.
abstract: Herein we investigate the scope and limitations of a new synthetic approach towards α- and β-ketopyranosides relying on the functionalization of the anomeric C-H bond of carbohydrates by insertion of a metal carbene. A key bromoacetate grafted at the 2-position is the cornerstone of a stereoselective glycosylation/diazotransfer/quaternarization sequence that makes possible the construction of a quaternary center with complete control of the stereochemistry. This sequence shows a good tolerance toward protecting groups commonly used in carbohydrate chemistry and gives rise to quaternary disaccharides with good efficiency. In the case of a disaccharide with a more restricted conformation, this functionalization process can be hampered by the steric demand next to the targeted anomeric position. In addition, the formation of transient orthoesters during the glycosylation step may also reduce the overall efficiency of the synthetic sequence.
authors: UMR 8601 CNRS, Université Paris Descartes, Sorbonne Paris Cité, UFR Biomédicale, 45 rue des Saints Pères, 75006 Paris, France.
authors: Mélissa
authors: M
authors: Boultadakis-Arapinis
authors: Elise
authors: E
authors: Prost
authors: Vincent
authors: V
authors: Gandon
authors: Pascale
authors: P
authors: Lemoine
authors: Serge
authors: S
authors: Turcaud
authors: Laurent
authors: L
authors: Micouin
authors: Thomas
authors: T
authors: Lecourt
mesh_terms: D002241:Carbohydrates / Q000737:chemistry*; D002625:Chemistry, Organic; D004187:Disaccharides / Q000737:chemistry*; D006027:Glycosides / Q000737:chemistry*; D006031:Glycosylation; D006860:Hydrogen Bonding; D008697:Methane / Q000031:analogs & derivatives* / Q000737:chemistry; D008968:Molecular Conformation; D012238:Rhodium / Q000737:chemistry*
chemical_list: D002241:Carbohydrates; D004187:Disaccharides; D006027:Glycosides; C030011:carbene; D012238:Rhodium; D008697:Methane