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.
The highly α-selective and scalable synthesis of the Fmoc-n class="Chemical">protectedGalNAc-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 trihaloacetimidatedonors 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-protectedGalNAc-threonine and TN antigen. This operationally simple procedure no longer requires utilization of the commonly used C(2)-azidodonors and overcomes many of the limitations associated with the synthesis of 1,2-cis linkage.
Authors: A Leppänen; P Mehta; Y B Ouyang; T Ju; J Helin; K L Moore; I van Die; W M Canfield; R P McEver; R D Cummings Journal: J Biol Chem Date: 1999-08-27 Impact factor: 5.157
Authors: Francisco Corzana; Jesús H Busto; Gonzalo Jiménez-Osés; Marisa García de Luis; Juan L Asensio; Jesús Jiménez-Barbero; Jesús M Peregrina; Alberto Avenoza Journal: J Am Chem Soc Date: 2007-07-07 Impact factor: 15.419