title: Nickel-catalyzed stereoselective formation of alpha-2-deoxy-2-amino glycosides.
abstract: The development of a new method for the stereoselective synthesis of alpha-2-deoxy-2-amino glycosides is described. This methodology relies on the nature of the cationic nickel catalyst, generated in situ from L(n)NiCl(2) and AgOTf, to direct the anomeric stereoselectivity. The new glycosylation reaction is highly alpha-selective and proceeds under mild conditions with 5-10 mol % of the nickel catalyst loading at ambient temperature. This new method has been applied to both D-glucosamine and galactosamine trichloroacetimidate donors as well as an array of primary, secondary, and tertiary alcohol nucleophiles to provide the desired glycoconjugates in good yields with excellent alpha-selectivity. Mechanistic studies of the present reaction are underway and will be reported in due course.
authors.affiliation: Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana 59717, USA.
authors.forename: Enoch A
authors.initials: EA
authors.lastname: Mensah
authors.forename: Hien M
authors.initials: HM
authors.lastname: Nguyen
mesh_terms: D000617:Aminoglycosides / Q000138:chemical synthesis* / Q000737:chemistry; D002384:Catalysis; D005688:Galactosamine / Q000138:chemical synthesis / Q000737:chemistry; D005944:Glucosamine / Q000138:chemical synthesis / Q000737:chemistry; D006001:Glycoconjugates / Q000138:chemical synthesis* / Q000737:chemistry; D006031:Glycosylation; D009532:Nickel / Q000737:chemistry*; D013237:Stereoisomerism
chemical_list: D000617:Aminoglycosides; D006001:Glycoconjugates; D005688:Galactosamine; D009532:Nickel; D005944:Glucosamine