582
3
Chemical Glycosylation Reactions
⊡ Scheme 12
Reactions of pyranosylacetonitrilium ions arising from NPGs
2.5.3 Synthesis of N-β-Linked Glycoproteins from Pyranosylacetonitrilium Ions
More interestingly, the presence of a neighboring participating group at C2 induces the formation of β-nitrilium ion intermediates, e. g. 94 ( > Scheme 12d), thus paving the way to β-linked
glycoproteins [62]. Accordingly, phthalimido NPG 93, reacted with aspartic acid derivative
88, in acetonitrile using NBS as promoter, via the β-nitrilium intermediate 94, to give the
β-asparagine-linked product 95 in 48% yield.
More recently, this method has been elaborated in a three-component-reaction (NPG, acetonitrile, carboxylic acid) route to N-glycosylamines [63].
3
Chemical Glycosylation Reactions
⊡ Scheme 12
Reactions of pyranosylacetonitrilium ions arising from NPGs
2.5.3 Synthesis of N-β-Linked Glycoproteins from Pyranosylacetonitrilium Ions
More interestingly, the presence of a neighboring participating group at C2 induces the formation of β-nitrilium ion intermediates, e. g. 94 ( > Scheme 12d), thus paving the way to β-linked
glycoproteins [62]. Accordingly, phthalimido NPG 93, reacted with aspartic acid derivative
88, in acetonitrile using NBS as promoter, via the β-nitrilium intermediate 94, to give the
β-asparagine-linked product 95 in 48% yield.
More recently, this method has been elaborated in a three-component-reaction (NPG, acetonitrile, carboxylic acid) route to N-glycosylamines [63].