O-Glycosyl Donors
3.4
605
⊡ Scheme 34
Convergent synthesis of nonamannan 227. Synthesis of the tetrasaccharide acceptor 236b and final assembly
tetrasaccharide 245 in 65% yield. The final stages in the preparation of 237 involved: (i) FeCl 3
debenzylation, (ii) silylation of the resulting free –OHs, (iii) deprotection of the TCP and condensation with an activated fatty acid, (iv) removal of the phthalimido protecting groups, and
(v) acylation, saponification, and desilylation.
2.11.4 Synthesis of Phosphorylated Rat Brain
Thy-1 Glycosylphosphatidylinositol Anchor
Glycosylphosphatidylinositol (GPI) membrane anchors constitute a class of glycolipids that
covalently link certain proteins to cell and virion surfaces [122,123]. A boost in their chemistry occurred in 1988 when Ferguson et al. reported the first covalent structure of a member of this family [124,125]. The first synthesis of a fully phosphorylated GPI, compound
246 ( > Fig. 5), was accomplished by Fraser-Reid’s group based entirely on NPG chemistry [126,127,128,129,130].
3.4
605
⊡ Scheme 34
Convergent synthesis of nonamannan 227. Synthesis of the tetrasaccharide acceptor 236b and final assembly
tetrasaccharide 245 in 65% yield. The final stages in the preparation of 237 involved: (i) FeCl 3
debenzylation, (ii) silylation of the resulting free –OHs, (iii) deprotection of the TCP and condensation with an activated fatty acid, (iv) removal of the phthalimido protecting groups, and
(v) acylation, saponification, and desilylation.
2.11.4 Synthesis of Phosphorylated Rat Brain
Thy-1 Glycosylphosphatidylinositol Anchor
Glycosylphosphatidylinositol (GPI) membrane anchors constitute a class of glycolipids that
covalently link certain proteins to cell and virion surfaces [122,123]. A boost in their chemistry occurred in 1988 when Ferguson et al. reported the first covalent structure of a member of this family [124,125]. The first synthesis of a fully phosphorylated GPI, compound
246 ( > Fig. 5), was accomplished by Fraser-Reid’s group based entirely on NPG chemistry [126,127,128,129,130].