title: O-Alkylated heavy atom carbohydrate probes for protein X-ray crystallography: Studies towards the synthesis of methyl 2-O-methyl-L-selenofucopyranoside.
abstract: Selenoglycosides are used as reactive glycosyl donors in the syntheses of oligosaccharides. In addition, such heavy atom analogs of natural glycosides are useful tools for structure determination of their lectin receptors using X-ray crystallography. Some lectins, e.g., members of the tectonin family, only bind to carbohydrate epitopes with O-alkylated ring hydroxy groups. In this context, we report the first synthesis of anO-methylated selenoglycoside, specifically methyl 2-O-methyl-L-selenofucopyranoside, a ligand of the lectin tectonin-2 from the mushroomLaccaria bicolor. The synthetic route required a strategic revision and further optimization due to the intrinsic lability of alkyl selenoglycosides, in particular for the labile fucose. Here, we describe a successful synthetic access to methyl 2-O-methyl-L-selenofucopyranoside in 9 linear steps and 26% overall yield starting from allyl L-fucopyranoside.
authors.affiliation: Chemical Biology of Carbohydrates, Helmholtz Institute for Pharmaceutical Research Saarland (HIPS), D-66123 Saarbrücken, Germany; Deutsches Zentrum für Infektionsforschung (DZIF), Standort Hannover-Braunschweig, Germany.
authors.forename: Roman
authors.initials: R
authors.lastname: Sommer
authors.affiliation: Chemical Biology of Carbohydrates, Helmholtz Institute for Pharmaceutical Research Saarland (HIPS), D-66123 Saarbrücken, Germany; Deutsches Zentrum für Infektionsforschung (DZIF), Standort Hannover-Braunschweig, Germany.
authors.forename: Dirk
authors.initials: D
authors.lastname: Hauck
authors.affiliation: Centre de Recherche sur les Macromolécules Végétales (CERMAV-UPR5301), CNRS and Université Grenoble Alpes, BP53, F-38041 Grenoble cedex 9, France.
authors.forename: Annabelle
authors.initials: A
authors.lastname: Varrot
authors.affiliation: Centre de Recherche sur les Macromolécules Végétales (CERMAV-UPR5301), CNRS and Université Grenoble Alpes, BP53, F-38041 Grenoble cedex 9, France.
authors.forename: Anne
authors.initials: A
authors.lastname: Imberty
authors.affiliation: Institute of Microbiology, Swiss Federal Institute of Technology (ETH) Zürich, 8093 Zürich, Switzerland.
authors.forename: Markus
authors.initials: M
authors.lastname: Künzler
authors.affiliation: Chemical Biology of Carbohydrates, Helmholtz Institute for Pharmaceutical Research Saarland (HIPS), D-66123 Saarbrücken, Germany; Deutsches Zentrum für Infektionsforschung (DZIF), Standort Hannover-Braunschweig, Germany.
authors.forename: Alexander
authors.initials: A
authors.lastname: Titz
keywords: carbohydrate chemistry; fucose; lectin; selenoglycoside