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The 2‐Naphthylmethyl (NAP) Group in Carbohydrate Synthesis: First Total Synthesis of the GlyCAM‐1 Oligosaccharide Structures
Author(s) -
Xia Jie,
Alderfer James L.,
Piskorz Conrad. F.,
Matta Khushi L.
Publication year - 2001
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/1521-3765(20010119)7:2<356::aid-chem356>3.0.co;2-e
Subject(s) - nap , oligosaccharide , carbohydrate , chemistry , total synthesis , stereochemistry , group (periodic table) , organic chemistry , biology , neuroscience
Total syntheses of the GlyCAM‐1 (glycosylation‐dependent cell adhesion molecule‐1) oligosaccharide structures: { α ‐NeuAc‐(2→3)‐ β ‐Gal‐(1→4)‐[ α ‐Fuc‐(1→3)]‐ β ‐(6‐ O ‐SO 3 Na)‐GlcNAc‐(1→6)}‐[ α ‐NeuAc‐(2→3)‐ β ‐Gal‐(1→3)]‐ α ‐GalNAc‐OMe ( 1 ) and { α ‐NeuAc‐(2→3)‐ β ‐Gal‐(1→4)‐[ α ‐Fuc‐(1→3)]‐ β ‐GlcNAc‐(1→6)}‐[ α ‐NeuAc‐(2→3)‐ β ‐Gal‐(1→3)]‐ α ‐GalNAc‐OMe ( 2 ) through a novel sialyl Lewis x tetrasaccharide donor are described. Employing sequential glycosylation strategy, the starting trisaccharide was regio‐ and stereoselectively constructed through coupling of a disaccharide imidate with the monosaccharide acceptor phenyl‐6‐ O ‐naphthylmethyl‐2‐deoxy‐2‐phthalimido‐1‐thio‐ β ‐ D ‐glucopyranoside with TMSOTf as a catalyst without affecting the SPh group. The novel sialyl Lewis x tetrasaccharide donor 3 was then obtained by α ‐ L ‐fucosylation of trisaccharide acceptor with the 2,3,4‐tri‐ O ‐benzyl‐1‐thio‐ β ‐ L ‐fucoside donor. The structure of the novel sialyl Lewis x tetrasaccharide was established by a combination of 2D DQF‐COSY and 2D ROESY experiments. Target oligosaccharides 1 and 2 were eventually constructed through heptasaccharide which was obtained by regioselective assembly of advanced sialyl Lewis x tetrasaccharide donor 3 and a sialylated trisaccharide acceptor in a predictable and controlled manner. Finally, target heptasaccharides 1 and 2 were fully characterized by 2D DQF‐COSY, 2D ROESY, HSQC, HMBC experiments and FAB mass spectroscopy.