PhCH2O), 4.73 (d, 1H, J = 12.1 Hz, PhCH2O), 4.71 (d, 1H,
J1D,2D = 7.2 Hz, H-1D), 4.63 (dd, 1H, J1B,2B = 1.8 Hz, J2B,3B
J1B,2B = 1.5 Hz, H-1B), 5.17 (s, 1H, H-1D), 4.99 (d, 1H, J =
10.9 Hz, PhCH2O), 4.96 (d, 1H, J = 11.6 Hz, PhCH2O),
4.90–4.88 (m, 2H, PhCH2O), 4.78 (d, 1H, J = 10.4 Hz,
PhCH2O), 4.76–4.75 (m, 1H, H-2B), 4.69 (d, 1H, J = 12.1 Hz,
PhCH2O), 4.66 (s, 1H, H-1C), 4.61–4.39 (m, 10H, H-2C,
PhCH2O), 4.30–4.28 (m, 2H, H-2D, H-5B), 4.27 (d, 1H, J =
10.6 Hz, PhCH2O), 4.24 (d, 1H, J = 10.4 Hz, PhCH2O), 4.06 (d,
1H, J = 11.7 Hz, PhCH2O), 3.99–3.88 (m, 3H, H-4C, H-3B,
H-4D), 3.84–3.68 (m, 6H, H-4B, H-6aB, H-6aC, H-6bC,
=
3.2 Hz, H-2B), 4.61 (d, 1H, J = 11.1 Hz, PhCH2O), 4.54–4.40
(m, 9H, H-1C, PhCH2O), 4.38–4.34 (m, 3H, PhCH2O, H-2C),
4.30 (t, 1H, J3B,4B = 9.6 Hz, H-4B), 4.27–4.24 (m, 1H, H-5B),
3.91 (dd, 1H, J5B,6aB = 4.1 Hz, J6aB,6bB = 10.6 Hz, H-6aB), 3.86
(t, 1H, J3C,4C = 9.6 Hz, H-4C), 3.82–3.77 (m, 2H, H-3B, H-2D),
3.72–3.65 (m, 4H, H-3D, H-6bB, H-6aC, H-6bC), 3.62–3.52
(m, 4H, H-6aD, H-6bD, H-5D, H-4D), 3.48 (dd, 1H, J2C,3C
=
3.2 Hz, J3C,4C = 9.4 Hz, H-3C), 3.44–3.41 (m, 1H, H-5C); 13C
NMR (125 MHz, CDCl3) δ 139.1 (Ar), 138.6 (Ar), 138.5 (Ar),
138.4 (Ar), 138.1 (Ar), 138.05 (Ar), 138.04 (Ar), 138.0 (Ar),
137.8 (Ar), 134.4 (Ar), 131.2 (Ar), 129.1 (Ar), 128.5 (Ar), 128.4
(Ar), 128.3 (Ar), 128.29 (Ar), 128.28 (Ar), 128.27 (Ar), 128.26
(Ar), 128.20 (Ar), 128.19 (Ar), 128.15 (Ar), 128.03 (Ar), 128.0
(Ar), 127.9 (Ar), 127.83 (Ar), 127.80 (Ar), 127.7 (Ar), 127.58
(Ar), 127.57 (Ar), 127.56 (Ar), 127.55 (Ar), 127.53 (Ar), 127.51
H-6aD, H-6bD), 3.64 (dd, 1H, J5B,6bB = 2.0 Hz, J6bB,6aB =
10.6 Hz, H-6bB), 3.60–3.54 (m, 2H, H-3C, H-5D), 3.50–3.46
(m, 2H, H-3D, H-5C), 2.62 (s, br, 1H, OH); 13C NMR
(125 MHz, CDCl3) δ 138.6 (Ar), 138.5 (Ar), 138.2 (Ar), 138.17
(Ar), 138.15 (Ar), 138.12 (Ar), 138.07 (Ar), 138.05 (Ar), 137.7
(Ar), 134.4 (Ar), 131.1 (Ar), 129.1 (Ar), 129.0 (Ar), 128.5 (Ar),
128.4 (Ar), 128.38 (Ar), 128.34 (Ar), 128.32 (Ar), 128.31 (Ar),
128.29 (Ar), 128.26 (Ar), 128.2 (Ar), 128.1 (Ar), 128.0 (Ar),
127.9 (Ar), 127.8 (Ar), 127.74 (Ar), 127.73 (Ar), 127.62 (Ar),
127.59 (Ar), 127.47 (Ar), 127.45 (Ar), 127.42 (Ar), 127.26 (Ar),
100.0 (JC–1D,H–1D = 163 Hz, C-1D), 97.3 (JC–1C,H–1C = 155 Hz,
C-1C), 84.53 (JC–1B,H–1B = 166 Hz, C-1B), 83.1 (C-3D), 79.9
(C-3C), 78.4 (C-3B), 75.6 (C-5C), 75.4 (PhCH2O), 75.3 (C-5D),
75.17 (PhCH2O), 75.12 (PhCH2O), 74.9 (C-4B), 74.3 (C-4D),
74.1 (C-4C), 73.54 (PhCH2O), 73.52 (PhCH2O), 73.4
(PhCH2O), 71.9 (C-5B), 71.6 (C-2B), 71.4 (C-2C), 70.3
(PhCH2O), 70.2 (C-6C), 69.8 (C-6D), 69.7 (PhCH2O), 68.5
(C-6B), 67.4 (C-2D); HRMS [ESI] calcd for C87H90O15SNa
1429.5893, found 1429.5885.
(Ar), 127.46 (Ar), 127.38 (Ar), 127.2 (Ar), 105.3 (JC–1D,H–1D
=
161 Hz, C-1D), 97.5 (JC–1C,H–1C = 155 Hz, C-1C), 86.7 (C-3D),
85.5 (JC–1B,H–1B = 168 Hz, C-1B), 79.5 (C-3C), 78.3 (C-3B),
77.2 (C-4D), 75.6 (PhCH2O), 75.5 (C-5C), 75.4 (C-2D), 75.2
(PhCH2O), 75.0 (C-5D), 74.96 (PhCH2O), 74.95 (PhCH2O),
74.9 (C-2C), 74.3 (C-4C), 74.0 (C-4B), 73.7 (PhCH2O), 73.4
(PhCH2O), 73.35 (PhCH2O), 73.1 (C-2B), 72.2 (C-5B), 70.5
(PhCH2O), 69.9 (C-6D), 69.8 (PhCH2O), 69.7 (C-6C), 68.9
(C-6B); HRMS [ESI] calcd for C87H90O15SNa 1429.5893,
found 1429.5889.
Phenyl 3,4,6-tri-O-benzyl-β-D-mannopyranosyl-(1 → 2)-3,4,6-
tri-O-benzyl-β-D-mannopyranosyl-(1 → 2)-3,4,6-tri-O-benzyl-1-
thio-α-D-mannopyranoside (9). Solution of oxalyl chloride
(32 μL, 382 μmol) in CH2Cl2 (1.0 mL) was added dropwise to a
solution of 8 (269 mg, 191 μmol) and dimethyl sulfoxide
(54.0 μL, 764 μmol) in CH2Cl2 (20 mL), at −78 °C a. The reac-
tion mixture was stirred at −78 °C for 40 min, and triethylamine
(106 μL, 764 μmol) was added. Stirring was continued until
temperature reached 0 °C (approx. 1.5 h), and the reaction was
quenched with a 1 M aqueous solution of HCl. The mixture was
washed with a saturated solution of NaHCO3, dried over
MgSO4, and filtered. Solvent was removed under reduced
pressure, and the residue was dried under vacuum to afford the
desired ketone as a light yellow oil: Rf = 0.28 (70 : 30 Hexane :
EtOAc). The crude product of ketone (268 mg, 191 μmol) was
dissolved in THF (24 mL), cooled to −78 °C, and a 1 M solution
of L-selectride in THF (400 μL, 764 μmol) was added dropwise.
The reaction mixture was stirred for 30 min at −78 °C and
quenched with methanol. After 5 min, the mixture was diluted
with CH2Cl2, washed with a 10% aqueous solution of H2O2, a
saturated solution of NaHCO3, H2O, brine, dried over Na2SO4,
and filtered. Solvent was removed under reduced pressure.
Column chromatography (85 : 15 to 80 : 20 Hexane : EtOAc) of
the crude product yielded 9 (176 mg, 65% for 2 steps) as a col-
ourless oil: Rf = 0.28 (30 : 70 EtOAc : hexanes); [α]D −10.5 (c
0.2, CHCl3); IR ν 3516 (w, br), 3087 (w), 3062 (m), 3030 (m),
2905 (m), 2864 (s), 1605 (w), 1584 (w), 1497 (m), 1453 (s),
1366 (m), 1316 (m), 1208 (m), 1100 (s), 1028 (s), 737 (s), 698
Phenyl 2-O-acetyl-3,4,6-tri-O-benzyl-β-D-mannopyranosyl-(1
→ 2)-3,4,6-tri-O-benzyl-β-D-mannopyranosyl-(1 → 2)-3,4,6-tri-
O-benzyl-1-thio-α-D-mannopyranoside (10). A mixture of 9
(38.8 mg, 27.6 μmol), triethylamine (80 μL, 577 μmol),
4-dimethylaminopyridine (4.01 mg, 32.7 μmol), and acetic
anhydride (26 μL, 275 μmol) in CH2Cl2 (1.0 mL) was stirred at
room temperature for 22 h. The reaction mixture was quenched
with MeOH and solvents were removed under reduced pressure.
Column chromatography (99 : 1 CH2Cl2 : EtOAc) of the crude
product yielded 10 (33.3 mg, 83%) as a colourless oil: Rf = 0.48
(98 : 2 CH2Cl2 : EtOAc); [α]D −7.0 (c 1.5, CHCl3); IR ν 3088
(w), 3062 (w), 3030 (m), 2925 (m), 2863 (m), 1744 (s), 1604
(w), 1584 (w), 1496 (m), 1454 (s), 1367 (s), 1316 (m), 1238 (s),
1
1102 (s), 1027 (s), 739 (s), 698 (s) (cm−1); H NMR (600 MHz,
CDCl3) δ 7.55–7.54 (m, 2H, ArH), 7.51–7.50 (m, 2H, ArH),
7.44–7.42 (m, 2H, ArH), 7.39–7.36 (m, 2H, ArH), 7.35–7.12
(m, 38H, ArH), 7.10–7.09 (m, 2H, ArH), 7.03–7.01 (m, 2H,
ArH), 5.73 (d, 1H, J1D,2D = 3.2 Hz, H-2D), 5.68 (d, 1H, J1B,2B
=
1.5 Hz, H-1B), 5.52 (s, 1H, H-1D), 4.97 (d, 1H, J = 10.7 Hz,
PhCH2O), 4.92–4.86 (m, 3H, PhCH2O), 4.82 (d, 1H, J = 10.5
Hz, PhCH2O), 4.78–4.77 (m, 1H, H-2B), 4.70 (s, 1H, H-1C),
4.69 (d, 1H, J2C,3C = 3.0 Hz, H-2C), 4.65 (d, 1H, J = 12.2 Hz,
PhCH2O), 4.60 (d, 1H, J = 12.0 Hz, PhCH2O), 4.55 (d, 1H, J =
11.0 Hz, PhCH2O), 4.54 (d, 1H, J = 10.9 Hz, PhCH2O),
4.51–4.43 (m, 5H, PhCH2O), 4.39 (d, 1H, J = 12.2 Hz,
PhCH2O), 4.38 (d, 1H, J = 11.3 Hz, PhCH2O), 4.31 (d, 1H, J =
10.5 Hz, PhCH2O), 4.30–4.28 (m, 1H, H-5B), 3.98 (d, 1H, J =
1
(s) (cm−1); H NMR (600 MHz, CDCl3) δ 7.51–7.47 (m, 4H,
11.2 Hz, PhCH2O), 3.94 (dd, 1H, J2B,3B = 3.4 Hz, J3B,4B =
ArH), 7.41–7.39 (m, 2H, ArH), 7.32–7.12 (m, 40H, ArH),
7.10–7.08 (m, 2H, ArH), 6.99–6.97 (m, 2H, ArH), 5.68 (d, 1H,
9.1 Hz, H-3B), 3.89 (t, 1H, J3D,4D ≈ J4D,5D ≈ 9.5 Hz, H-4D),
3.86 (t, 1H, J3,4 ≈ J4,5 ≈ 9.4 Hz, H-4B), 3.80–3.78 (m, 4H,
8356 | Org. Biomol. Chem., 2012, 10, 8348–8360
This journal is © The Royal Society of Chemistry 2012