3
CDCl ): δ 7.36-7.26 (m, 5H), 5.72 (d, 1H, J = 9.0
Benzyl
(2,3,4,6-tetra-O-acetyl-β-D-
Hz), 5.34 (d, 1H, J = 2.4 Hz), 5.29 (d, 1H, J = 3.0
Hz), 5.07 (dd, 1H, J = 10.2, 8.4 Hz), 4.98 (d, 1H, J
galactopyranosyl)-(1→3)-2-acetamido-4,6-
=
3.0 Hz), 4.90 (dd, 1H, J = 10.2, 3.0 Hz), 4.65 (d,
H, J = 11.4 Hz), 4.55 (d, 1H, J =8.4 Hz), 4.49
(td, 1H, J =9.0, 3.6 Hz), 4.42 (d, 1H, J =11.4 Hz),
.16-4.11 (m, 2H), 4.08 (t, 1H, J =6.0 Hz), 3.97
dd, 1H, J =12.6, 8.4 Hz), 3.90 (dd, 1H, J =11.4,
.6 Hz), 3.83 (t, 1H, J =6.6 Hz), 2.09 (s, 3H), 2.07
s, 3H), 2.04 (s, 3H), 2.00 (s, 3H), 1.98 (s, 3H),
benzylidene-2-deoxy-α-D-galactopyranoside (3)
1
(
23)
Acceptor 1 (4.85 g, 12.1 mmol) and Hg(CN)
6.50 g, 25.6 mmol) were suspended in a solution
(1:1, 240 mL). The mixture
2
4
(
3
(
(
of benzene/MeNO
was distilled until 120 mL of solvent was
removed. The temperature was then adjusted to
4
α-D-galactopyranosyl bromide 2 (24) (10.0 g, 24.3
mmol) in a solution of benzene/MeNO (1:1, 48
mL) was added. The resulting mixture was stirred
2
1
3
o
1
1
1
3
.91 (s, 6H). C-NMR (150 MHz, CDCl ): δ
70.4, 170.3, 170.2, 170.0 (2C), 169.6, 169.5,
36.6, 128.5, 128.3, 128.2, 100.3, 97.0, 72.6, 70.6
0-45 C after which donor 2,3,4,6-tetra-O-acetyl-
2
(
2C), 70.0, 68.7, 68.4, 67.4, 66.6, 62.5, 61.0, 23.1,
o
2
0.6 (3C), 20.5 (2C), 20.4.
at 40-45 C overnight, then cooled to r.t., diluted
with benzene (300 mL), and filtered. The organic
2
,3,4,6-Tetra-O-acetyl-β-D-galactopyranosyl-
layer was washed with sat. NaHCO
3
, 10% KI, and
). After
(
1→3)-2-acetamido-4,6-di-O-acetyl-2-deoxy-D-
brine, after which it was dried (MgSO
4
galactopyranose (6) (25)
Compound 5 (2.57 g, 3.54 mmol) was
dissolved in acetic acid (50 mL) and Pd(OH)
filtration and removal of the solvent the residue
was dried under vacuum to yield product 3 as
clear syrup (23) that was used in the next step
without further purification.
2
(
300 mg) was added to form a suspension. The
2
atmosphere of the reaction was replaced by H and
the reaction stirred at r.t. overnight. The mixture
was then filtered by Celite, washed with MeOH,
and the solvent removed under reduced pressure.
The residue was co-evaporated with toluene (3
x15 mL) after which the desired material was
purified by gradient silica gel flash column
chromatography using as the mobile phase
chloroform/acetone (1:1.5 to 1:1) to obtain
Benzyl (2,3,4,6-tetra-O-acetyl-β-D-
galactopyranosyl)-(1→3)-2-acetamido-2-deoxy
-
α-D-galactopyranoside (4) (23)
Compound 3 was dissolved in aq. 60% HOAc
o
(
140 mL), stirred at 60 C overnight, cooled to r.t.,
after which the solvent was removed under high
vacuum and the residue co-evaporated with
toluene (4 x 30 mL). The resulting residue was
then dried under vacuum to yield product 4 as a
solid foam (23) that was used in the next step
reaction without further purification.
1
product 6 as a solid foam (2.02 g, 90%) (25). H-
NMR (600 MHz, CDCl
Hz), 5.37 (d, 1H, J = 2.4 Hz), 5.34 (dd, 1H, J =
.6, 0.6 Hz), 5.33 (t, 1H, J = 3.6Hz), 5.11 (dd, 1H,
J = 10.2, 7.8 Hz), 4.94 (dd, 1H, J =10.2, 3.6 Hz),
3
): δ 6.02 (d, 1H, J = 8.4
3
Benzyl (2,3,4,6-tetra-O-acetyl-β-D-
4
9
3
.63 (d, 1H, J = 7.8 Hz), 4.40 (ddd, 1H, J = 11.4,
.0, 3.6 Hz), 4.33 (t, 1H, J =6.6 Hz), 4.15-4.11 (m,
H), 4.05 (dd, 1H, J =10.8, 3.6 Hz), 3.96 (dd, 1H,
galactopyranosyl)-(1→3)-2-acetamido-4,6-di-O-
acetyl-2-deoxy-α-D-galactopyranoside (5) (22)
Compound 4 and DMAP (610 mg) were
dissolved in pyridine (50 mL) after which acetic
anhydride (4.60 mL, 48.4 mmol) was added at r.t.
The resulting mixture was stirred at r.t. overnight
and MeOH (10mL) was then added. The solvent
was removed under reduced pressure and the
resulting residue was co-evaporated with toluene
J =12.0, 7.2 Hz), 3.89 (td, 1H, J =7.8, 1.2 Hz),
2
3
.15 (s, 3H), 2.11 (s, 3H), 2.07 (s, 3H), 2.05 (s,
1
3
H), 2.04 (s, 3H), 2.00 (s, 3H), 1.96 (s, 3H). C-
): δ 170.7, 170.6, 170.5,
70.3, 170.1, 170.0, 169.9, 100.3, 92.0, 72.2, 70.8
2C), 70.0, 68.8, 68.6, 67.0, 66.7, 62.6, 61.0, 49.6,
NMR (150 MHz, CDCl
1
(
3
2
3.2, 20.8 (2C), 20.7, 20.6 (2C), 20.5.
(
4 x30 mL) to obtain a syrupy residue. Gradient
silica gel column chromatography using
chloroform: acetone (4:1 to 2:1) as the mobile
2
,3,4,6-Tetra-O-acetyl-β-D-galactopyranosyl-
(
1→3)-2-acetamido-4,5-di-O-acetyl-2-deoxy-D-
phase afforded product 5 as a solid foam (22)
1
galactose oxime (7)
(
5.36 g, 61 % for 3 steps). H-NMR (600 MHz,
5