title: Regioselective conversion of the secondary hydroxyl groups of D-glucuronic acid without the requirement of O-protecting groups.
abstract: Trifluoromethanesulfonic acid anhydride (triflic acid anhydride) transforms the bicyclic thiazolidinlactam 1 a into the crystalline elimination product 2, in which all four secondary hydroxyl groups of 1 a are differently functionalized. Compound 2 can then add nucleophiles with high chemo- and stereoselectivity. Altogether, the four secondary hydroxyl groups of D-glucuronic acid are selectively transformed without the need for any O-protecting groups. Minimizing the number of O-protecting groups is a prerequisite for the use of sugar scaffolds in molecular libraries. The hapalosin analogues 15, 16, 19, and 22 outline the strategy towards O-diversified glucose derivatives.
authors.affiliation: Fakultät für Chemie und Pharmazie, Universität Regensburg, Germany.
authors.forename: Károly
authors.initials: K
authors.lastname: Agoston
authors.forename: Armin
authors.initials: A
authors.lastname: Geyer
mesh_terms: D001643:Bridged Bicyclo Compounds / Q000737:chemistry; D018360:Crystallography, X-Ray; D047630:Depsipeptides / Q000138:chemical synthesis / Q000737:chemistry; D020723:Glucuronic Acid / Q000737:chemistry*; D017665:Hydroxyl Radical / Q000737:chemistry*; D007202:Indicators and Reagents; D007769:Lactams / Q000138:chemical synthesis / Q000737:chemistry; D007783:Lactones / Q000138:chemical synthesis / Q000737:chemistry; D008698:Mesylates; D008958:Models, Molecular; D008968:Molecular Conformation
chemical_list: D001643:Bridged Bicyclo Compounds; D047630:Depsipeptides; D007202:Indicators and Reagents; D007769:Lactams; D007783:Lactones; D008698:Mesylates; C111358:hapalosin; D017665:Hydroxyl Radical; D020723:Glucuronic Acid; C012077:trifluoromethanesulfonic acid