C. Krog-Jensen, S. Oscarson/Carbohydrate Research 308 (1998) 287±296
293
(Me3CCO), 52.3 (MeO), 70.8, 74.5, 78.3, 79.4, and
83.8 (C-1±5), 168.5 (COOMe), 176.7 (Me3CCO).
Anal. Calcd for C26H50O8Si2S: C, 53.94; H, 8.71.
Found: C, 54.11; H, 8.67.
General glycosidation procedure.ÐThe donor
(1.5 equiv) and acceptor (1 equiv) were dissolved in
CH2Cl2 (5 mL) and crushed 4 A molecular sieves
(0.3 g) was added and the mixture stirred under N2
for 30 min, whereafter DMTST (4 equiv) was
added. After an additional 12 h, Et3N (1.5 mL) was
added and the mixture was ®ltered through Celite
and concentrated. The residue was puri®ed directly
by silica gel chromatography.
using the general procedure (silica gel chromato-
graphy, 9:1 toluene±EtOAc) to give 18 (46 mg,
87%). If instead 2.5 equiv of 13 was reacted with
15 (23 mg, 56 ꢃmol) the disaccharide 18 was
obtained in 95% yield (51 mg); [ꢁ]d +10ꢀ (c 1.1,
CHCl3); NMR (CDCl3): 13C, ꢂ 12.2, 12.8, and 12.9
(CHSi), 17.0, 17.1, 17.16, and 17.20 (Me2CHSi),
52.2 and 54.8 (MeO), 63.9, 68.6, 71.9, 73.4, 74.3,
74.5, 76.2, 76.3, 77.2, and 78.2 (C-2±6,20±50,
PhCH2), 99.3, 100.7, and 101.4 (C-1,10, PhCH),
125.3±138.8 (C aromatic), 164.7 (PhCO), 168.2
1
(COOMe); H, ꢂ 4.55 (d, 1 H, J 1.7 Hz, H-1), 4.75
(d, 1 H, J 8.0 Hz, H-10).
Methyl {methyl [2-O-acetyl-3,4-O-(1,1,3,3-tetra-
isopropyl-1,3-disiloxane-1,3-diyl)-b-d-glucopyrano-
syl]uronate}-(1!2)-3-O-benzyl-4,6-O-benzylidene-
Methyl {methyl [2-O-pivaloyl-3,4-O-(1,1,3,3-tetra-
isopropyl-1,3-disiloxane-1,3-diyl)-b-d-glucopyrano-
syl]uronate}-(1!2)-3-O-benzyl-4,6-O-benzylidene-
a-d-mannopyranoside (19).ÐDonor 14 (50 mg,
86 ꢃmol) and 15 (24 mg, 58 mmol) were coupled
using the general procedure (silica gel chromato-
graphy, 9:1 toluene±EtOAc) to give 19 (29 mg,
53%) together with 30 mg of the suggested
dimer {methyl [2-O-pivaloyl-3,4-O-(1,1,3,3-tetra-
isopropyl-1,3-disiloxane-1,3-diyl)-b-d-glucopyrano-
syl]uronate}-(1!2)-1-O-pivaloyl-3,4-O-(1,1,3,3-
tetraisopropyl-1,3-disiloxane-1,3-diyl)-a-d-gluco-
pyranuronate (21).
If instead 2.5 equiv of 14 (100 mg, 173 ꢃmol) was
reacted with 15 (29 mg, 69 ꢃmol), 59% of the di-
saccharide 19 (38 mg) was obtained together with
the dimer 21 (45 mg). 19: [ꢁ]d +11ꢀ (c 1.4, CHCl3);
NMR (CDCl3): 13C, ꢂ 12.3, 12.4, 12.7, and 13.1
(CHSi), 17.1, 17.2, 17.3, 17.5, and 17.7 (Me2CHSi),
27.2 and 27.3 (Me3CCO), 38.9 (Me3CCO), 52.2
and 54.8 (MeO), 64.2, 68.8, 71.4, 72.6, 74.1, 74.3,
75.4, 75.9, 77.3, and 78.0 (C-2±6,20±50, PhCH2),
99.4, 100.4, and 101.4 (C-1,10, PhCH), 126.1-138.8
(C aromatic), 168.1 (COOMe), 176.3 (Me3CCO);
1H, ꢂ 4.55 (d, 1 H, J 8.5 Hz, H-10), 4.59 (d, 1 H, J
1.3 Hz, H-1). Anal. Calcd for C45H68O14Si2: C,
60.78; H, 7.71. Found: C, 60.50; H, 7.64.
a-d-mannopyranoside (17).ÐDonor
7
(50 mg,
93 ꢃmol) and methyl 3-O-benzyl-4,6-O-benzyli-
dene-ꢁ-d-mannopyranoside (15; 26 mg, 62 ꢃmol)
[9] were coupled using the procedure described
above (silica gel chromatography 9:1 toluene±
EtOAc) to give 17 (38 mg, 69%) together with 5 mg
of the suggested dimer {methyl [2-O-acetyl-3,4-O-
(1,1,3,3-tetraisopropyl-1,3-disiloxane-1,3-diyl)-ꢀ-d-
glucopyranosyl]uronate}-(1!2)-1-O-acetyl-3,4-O-
(1,1,3,3-tetraisopropyl-1,3-disiloxane-1,3-diyl)-ꢁ-d-
glucopyranuronate (20).
If instead 2.5 equiv of 7 (50 mg, 93 ꢃmol) was reac-
ted with 15 (16 mg, 37 ꢃmol), 45% of the disaccharide
17 (15 mg) was obtained together with the dimer 20
(25 mg); 17: [ꢁ]d +6ꢀ (c 0.9, CHCl3); NMR (CDCl3):
13C, ꢂ 12.2, 12.8, and 12.9 (CHSi), 17.1 and 17.2
(Me2CHSi), 20.6 (MeCO), 52.2 and 54.9 (MeO),
64.1, 68.8, 71.8, 72.5, 74.0, 74.3, 76.0, 76.1, and 78.1
(C-2±6,20±50, PhCH2), 99.6, 100.5, and 101.5 (C-1,10,
PhCH), 126.1±138.7 (C aromatic), 168.0 and 168.8
(MeCO, COOMe); 1H, ꢂ 4.52 (d, 1 H, J 8.0 Hz, H-
10), 4.65 (s, 1 H, H-1). Anal. Calcd for C42H62O14Si2:
C, 59.55; H, 7.38. Found: C, 61.06; H, 7.80.
20: [ꢁ]d +30ꢀ (c 1.0, CHCl3); NMR (CDCl3):
13C, ꢂ 12.1, 12.4, and 12.8 (CHSi), 17.1 and 17.4
(Me2CHSi), 20.9 (MeCO), 52.3 (MeO), 72.8, 73.0,
74.2, 74.5, 75.5, 76.2, and 77.4 (C-2±5), 90.9 (C-
1ꢁ), 101.0 (C-1ꢀ), 168.0, 168.8, 169.0, and 169.2
21: [ꢁ]d +67ꢀ (c 0.3, CHCl3); NMR (CDCl3):
13C, ꢂ 12.3, 12.4, 12.5, 12.7, 12.72, 12.8, 13.0, and
13.2 (CHSi), 17.0, 17.1, 17.2, 17.3, 17.4, 17.6, and
17.7 (Me2CHSi), 27.0, 27.2, and 27.3 (Me3CCO),
38.7 and 39.0 (Me3CCO), 52.4 (MeO), 73.0, 73.2,
73.8, 74.2, 74.4, 74.5, 75.7, and 79.4 (C-2±5), 90.7
(C-1ꢁ), 100.2 (C-1ꢀ), 168.3 and 169.1 (COOMe),
176.0 (Me3CCO); 1H, ꢂ 4.58 (d, 1 H, J 6 Hz, H-1ꢀ),
6.28 (d, 1 H, J 3.5 Hz, H-1ꢁ); MS (FAB+): m/z
1051.4 [M+H]+, 1073.6 [M+Na]+.
1
(MeCO, COOMe); H, ꢂ 4.72 (d, 1 H, J 7.9 Hz,
H-1ꢀ), 6.23 (d, 1 H, J 3.8 Hz, H-1ꢁ); MS (FAB+):
m/z 989.6 [M+Na]+.
Methyl {methyl [2-O-benzoyl-3,4-O-(1,1,3,3-tetra-
isopropyl-1,3-disiloxane-1,3-diyl)-b-d-glucopyrano-
syl]uronate}±(1!2)-3-O-benzyl-4,6-O-benzylidene-
a-d-mannopyranoside (18).ÐDonor 13 (50 mg,
84 ꢃmol) and 15 (23 mg, 56 ꢃmol) were coupled
2-(4-Nitrophenyl)ethyl {methyl [2-O-acetyl-3,4-
O-(1,1,3,3-tetraisopropyl-1,3-disiloxane-1,3-diyl)-