| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 1348259 | Tetrahedron: Asymmetry | 2007 | 14 Pages |
The use of propargyl mediated intramolecular aglycon delivery (IAD) for the synthesis of the key Manβ(1→4)GlcNAc linkage of N-glycan oligosaccharides, including the core N-glycan pentasaccharide, is investigated. Isomerisation of a 2-O-progargyl group of manno thioglycoside donors to an allene is followed by iodonium ion mediated mixed acetal formation with the 4-OH of protected GlcNAc acceptors, and subsequent intramolecular glycosylation occurs with complete control of anomeric stereochemistry to form the Manβ(1→4)GlcNAc linkage. A variety of linear and convergent approaches (1+2, 3+1, 3+2) to the core pentasaccharide are investigated as means of probing the generality and limitations of this type of intramolecular aglycon delivery for the formation of β-mannoside linkages in complex oligosaccharides.
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Methyl 4,6-O-benzylidene-3-O-tert-butyldiphenylsilyl-1-thio-α-d-mannopyranosideC30H36O5SSiEe = 100%[α]D17=+115 (c 1.0, CHCl3)Source of chirality: d-mannose
Methyl 4,6-O-benzylidene-2-O-(prop-2-ynyl)-3-O-tert-butyldiphenylsilyl-1-thio-α-d-mannopyranosideC33H38O5SSiEe = 100%[α]D17=+122 (c 0.9, CHCl3)Source of chirality: d-mannose
Methyl 4,6-O-benzylidene-2-O-(allenyl)-3-O-tert-butyldiphenylsilyl-1-thio-α-d-mannopyranosideC33H38O5SSiEe = 100%[α]D20=+67 (c 1.0, CHCl3)Source of chirality: d-mannose
Methyl 4,6-O-benzylidene-3-O-tert-butyldiphenylsilyl-2-O-(2-iodo-1-(para-methoxyphenyl 3,6-di-O-benzyl-2-deoxy-2-phthalimido-β-d-glucopyranosid-4-O-yl)prop-2-enyl)-1-thio-α-d-mannopyranosideC68H70INO13SSiEe = 100%[α]D20=+79 (c 0.8, CHCl3)Source of chirality: d-mannose, N-acetyl-d-glucosamine
p-Methoxyphenyl-4,6-O-benzylidene-3-O-tert-butyldiphenylsilyl-β-d-mannopyranosyl-(1→4)-3,6-di-O-benzyl-2-deoxy-2-phthalimido-β-d-glucopyranosideC64H65NO13SiEe = 100%[α]D21=+49 (c 1.0, CHCl3)Source of chirality: d-mannose, N-acetyl-d-glucosamine
p-Methoxyphenyl-4,6-O-benzylidene-β-d-mannopyranosyl-(1→4)-3,6-di-O-benzyl-2-deoxy-2-phthalimido-β-d-glucopyranosideC48H47NO13Ee = 100%[α]D17=+41 (c 0.8, CHCl3)Source of chirality: d-mannose, N-acetyl-d-glucosamine
p-Methoxyphenyl 2-O-acetyl-3,4,6-tri-O-benzyl-α-d-mannopyranosyl-(1→3)-2-O-acetyl-4,6-O-benzylidene-β-d-mannopyranosyl-(1→4)-3,6-di-O-benzyl-2-deoxy-2-phthalamido-β-d-glucopyranosideC79H79NO20Ee = 100%[α]D23=+20 (c 1.0, CHCl3)Source of chirality: d-mannose, N-acetyl-d-glucosamine
p-Methoxyphenyl 2-O-acetyl-3,4,6-tri-O-benzyl-α-d-mannopyranosyl-(1→3)-2-O-acetyl-β-d-mannopyranosyl-(1→4)-3,6-di-O-benzyl-2-deoxy-2-phthalamido-β-d-glucopyranosideC72H75NO20Ee = 100%[α]D23=+40 (c 0.5, CHCl3)Source of chirality: d-mannose, N-acetyl-d-glucosamine
p-Methoxyphenyl 2-O-acetyl-3,4,6-tri-O-benzyl-α-d-mannopyranosyl-(1→6)-[2-O-acetyl-3,4,6-tri-O-benzyl-α-d-mannopyranosyl-(1→3)]-2-O-acetyl-β-d-mannopyranosyl-(1→4)-3,6-di-O-benzyl-2-deoxy-2-phthalamido-β-d-glucopyranosideC101H105NO26Ee = 100%[α]D22=+39 (c 0.25, CHCl3)Source of chirality: d-mannose, N-acetyl-d-glucosamine
p-Methoxyphenyl 2,3,4,6-tetra-O-benzyl-α-d-mannopyranosyl-(1→6)-[2,3,4,6-tetra-O-benzyl-α-d-mannopyranosyl-(1→3)]-2,4-di-O-benzyl-β-d-mannopyranosyl-(1→4)-3,6-di-O-benzyl-2-deoxy-2-phthalamido-β-d-glucopyranosideC123H123NO23Ee = 100%[α]D17=+42 (c 0.5, CHCl3)Source of chirality: d-mannose, N-acetyl-d-glucosamine
p-Methoxyphenyl 2,3,4,6-tetra-O-benzyl-α-d-mannopyranosyl-(1→6)-[2,3,4,6-tetra-O-benzyl-α-d-mannopyranosyl-(1→3)]-2,4-di-O-benzyl-β-d-mannopyranosyl-(1→4)-3,6-di-O-benzyl-2-deoxy-2-phthalamido-β-d-glucopyranosyl-(1→4)-3,6-di-O-benzyl-2-deoxy-2-phthalamido-β-d-glucopyranosideC151H148N2O29Ee = 100%[α]D17=+30 (c 0.9, CHCl3)Source of chirality: d-mannose, N-acetyl-d-glucosamine
Methyl 4,6-O-benzylidene-2-O-(prop-2-ynyl)-1-thio-α-d-mannopyranosideC72H75NO20Ee = 100%[α]D20=+122 (c 0.8, CHCl3)Source of chirality: d-mannose
Methyl 2-O-acetyl-3,4,6-tri-O-benzyl-α-d-mannopyranosyl-(1→3)-2-O-(prop-2-ynyl)-1-thio-α-d-mannopyranosideC39H46O11SEe = 100%[α]D19=+35 (c 0.8, CHCl3)Source of chirality: d-mannose
Methyl 2-O-acetyl-3,4,6-tri-O-benzyl-α-d-mannopyranosyl-(1→3)-[2-O-acetyl-3,4,6-tri-O-benzyl-α-d-mannopyranosyl-(1→6)]-2-O-(prop-2-ynyl)-1-thio-α-d-mannopyranosideC68H76O17SEe = 100%[α]D17=+58 (c 1.0, CHCl3)Source of chirality: d-mannose
Methyl 2,3,4,6-tetra-O-benzyl-α-d-mannopyranosyl-(1→3)-[2,3,4,6-tetra-O-benzyl-α-d-mannopyranosyl-(1→6)]-4-O-benzyl-2-O-(prop-2-ynyl)-1-thio-α-d-mannopyranosideC85H90O15SEe = 100%[α]D17=+50 (c 1.0, CHCl3)Source of chirality: d-mannose
Methyl 2,3,4,6-tetra-O-benzyl-α-d-mannopyranosyl-(1→3)-[2,3,4,6-tetra-O-benzyl-α-d-mannopyranosyl-(1→6)]-4-O-benzyl-2-O-(allenyl)-1-thio-α-d-mannopyranosideC85H90O15SEe = 100%[α]D17=+52 (c 0.6, CHCl3)Source of chirality: d-mannose
p-Methoxyphenyl 4,6-O-benzylidene-3-O-tert-butyldiphenylsilyl-β-d-mannopyranosyl-(1→4)-3,6-di-O-benzyl-2-deoxy-2-phthalimido-β-d-glucopyranosyl-(1→4)-3,6-di-O-benzyl-2-deoxy-2-phthalimido-β-d-glucopyranosideC92H90N2O19SiEe = 100%[α]D22=+44 (c 1.0, CHCl3)Source of chirality: d-mannose, N-acetyl-d-glucosamine
