Stereoselective synthesis of O-serinyl/threoninyl-2-acetamido-2-deoxy-α- or β-glycosides
摘要:
General glycosidation methodology has been developed which can selectively provide 2acetamido-2-deoxy-alpha- or beta-glycosides of beta-hydroxy-alpha-amino acid derivatives [glucopyranoside- (8, 43), galactopyranoside- (9, 13), mannopyranoside- (10), lactoside analogs (11, 38) and 3-O-beta-galactopyranosyl-mannopyranoside (12)] stereoselectively in excellent yield from the highly nucleophilic a-imino esters (Schiff bases) of L-serine and L-threonine. Various glycosides were converted via their amino and acetamido derivatives to Fmoc-protected serinyl- or threoninyl-glycosides (24-28, 37, 41, 46) which are all suitable building blocks for the solid-phase synthesis of O-glycopeptides. Complete H-1- and C-13-NMR data are provided for all compounds.
Stereoselective synthesis of O-serinyl/threoninyl-2-acetamido-2-deoxy-α- or β-glycosides
摘要:
General glycosidation methodology has been developed which can selectively provide 2acetamido-2-deoxy-alpha- or beta-glycosides of beta-hydroxy-alpha-amino acid derivatives [glucopyranoside- (8, 43), galactopyranoside- (9, 13), mannopyranoside- (10), lactoside analogs (11, 38) and 3-O-beta-galactopyranosyl-mannopyranoside (12)] stereoselectively in excellent yield from the highly nucleophilic a-imino esters (Schiff bases) of L-serine and L-threonine. Various glycosides were converted via their amino and acetamido derivatives to Fmoc-protected serinyl- or threoninyl-glycosides (24-28, 37, 41, 46) which are all suitable building blocks for the solid-phase synthesis of O-glycopeptides. Complete H-1- and C-13-NMR data are provided for all compounds.