title: Scalable synthesis of Fmoc-protected GalNAc-threonine amino acid and T(N) antigen via nickel catalysis.
abstract: The highly α-selective and scalable synthesis of the Fmoc-protected GalNAc-threonine amino acid and TN antigen in gram scale (0.5-1 g) is described. The challenging 1,2-cis-2-amino glycosidic bond is addressed through a coupling of threonine residues with C(2)-N-ortho-(trifluoromethyl)benzylidenamino trihaloacetimidate donors mediated by Ni(4-F-PhCN)4(OTf)2. The desired 1,2-cis-2-amino glycoside was obtained in 66% yield (3.77 g) with α-only selectivity and subsequently transformed into the Fmoc-protected GalNAc-threonine and TN antigen. This operationally simple procedure no longer requires utilization of the commonly used C(2)-azido donors and overcomes many of the limitations associated with the synthesis of 1,2-cis linkage.
authors: Department of Chemistry, University of Iowa, Iowa City, Iowa 52242, United States.
authors: Fei
authors: F
authors: Yu
authors: Department of Chemistry, University of Iowa, Iowa City, Iowa 52242, United States.
authors: Matthew S
authors: MS
authors: McConnell
authors: Department of Chemistry, University of Iowa, Iowa City, Iowa 52242, United States.
authors: Hien M
authors: HM
authors: Nguyen
mesh_terms: D000117:Acetylglucosamine / Q000737:chemistry*; D015295:Antigens, Tumor-Associated, Carbohydrate / Q000737:chemistry*; D002384:Catalysis; D008968:Molecular Conformation; D009532:Nickel / Q000737:chemistry*; D009942:Organometallic Compounds / Q000737:chemistry*; D013912:Threonine / Q000737:chemistry*
chemical_list: D015295:Antigens, Tumor-Associated, Carbohydrate; D009942:Organometallic Compounds; C040286:Tn antigen; D013912:Threonine; D009532:Nickel; D000117:Acetylglucosamine