A new one-pot synthesis of Gb3 and isoGb3 trisaccharide analogues

Article abstract of DOI:10.1016/j.tet.2006.09.058

Gb₃ and isoGb₃ are both biologically important oligosaccharides. A new efficient synthesis of Gb₃ and isoGb₃ trisaccharide analogues has been achieved by one-pot sequential glycosylation strategy starting from s

Full text of DOI:10.1016/j.tet.2006.09.058

Tetrahedron 62 (2006) 11657–11662
A new one-pot synthesis of Gb3 and isoGb3 trisaccharide analogues
*
Changning Wang, Qin Li, Haisheng Wang, Li-He Zhang and Xin-Shan Ye
The State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences,
Peking University, Xue Yuan Rd #38, Beijing 100083, China
Received 17 July 2006; revised 14 September 2006; accepted 15 September 2006
Available online 16 October 2006
Abstract—Gb3 and isoGb3 are both biologically important oligosaccharides. A new efficient synthesis of Gb3 and isoGb3 trisaccharide
analogues has been achieved by one-pot sequential glycosylation strategy starting from simple monosaccharide building blocks promoted
by N-(phenylthio)-3-caprolactam at room temperature.
Ó 2006 Elsevier Ltd. All rights reserved.
1. Introduction
Gb3 also serves as a cell-surface receptor for Shiga-like
toxins (SLTs).3 Shiga-like toxins belong to a small but clini-
cally significant family of AB5 bacterial toxins. They consist
of a cytotoxic enzyme A subunit noncovalently linked to
a homopentameric cell-adhesion carrier, B5. The entry of
the enzymatic A subunit into the host cell relies on adhesion
of the B5 subunit to the cell membrane, a recognition that is
highly specific and mediated by multiple terminal trisaccha-
ride of Gb3, known as Pk-trisaccharide. Inhibition of inter-
actions between toxin B pentamer and its cell-surface
receptors hold a potential treatment for bacterial infections.
Glycosphingolipids1 are a class of naturally occurring bio-
active compounds usually embedded in the membrane of all
animal cells and some plant cells. The clinically important
blood group antigens and the immunologically relevant
tumor-associated antigens are examples of glycosphingo-
lipids. Gb3 glycolipid [a-D-Gal-(1/4)-b-D-Gal(1/4)-b-
D-Glc-1/O-ceramide] (Fig. 1) is highly enriched in Burkitt
lymphoma cell-lines, human teratocarcinoma, human
embryonal carcinoma, and other types of tumor cells, and
Gb3 glycolipid is also closely related to Fabry’s disease, a
lysosomal storage disorder caused by a deficiency of human
lysosomal a-galactosidase A.2
Another glycosphingolipid, isoGb3, also plays an important
role in many events.4 It was found to be associated with
OH
HO
OH
O
O
HO
C17H35
C13H27
HN
O
OH
OH
O
(a) R=
O
O
HO
HO
OR
OH
OH
OH
(b) R= Me,
(c) R=
1a
O
OH
HO
OH
O
C17H35
C13H27
HN
OH
OH
OH
O
O
HO
O
HO
O
OR
OH
OH
OH
(d) R= Me,
1b
Figure 1. The structures of Gb3, isoGb3, and their methyl glycoside analogues 1a and 1b.
Keywords: Gb3; isoGb3; Thioglycoside; One-pot synthesis; Glycosylation.
* Corresponding author. Tel.: +86 10 82801570; fax: +86 10 62014949; e-mail: xinshan@bjmu.edu.cn
0040–4020/$ - see front matter Ó 2006 Elsevier Ltd. All rights reserved.
doi:10.1016/j.tet.2006.09.058

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C. Wang et al. / Tetrahedron 62 (2006) 11657–11662
malignant neoplasms4a,b and shown that the Gal(al-3)Gal
segment of many glycosphingolipids can act as an attach-
ment site for bacteria, bacterial toxins, and viruses.4c,d
Recently, isoGb3 was disclosed as an endogenous ligand
for human NKT cells.4f,g
OH
OH
O
HO
HO
O
OH
O
OH
O
O
HO
OMe
HO
OH
OH
1a
Because of their biological significance as well as common
structures shared by various globo-series glycosphingo-
lipids, a number of Gb3/isoGb3 tri- and di-saccharide ana-
logues have been synthesized.5 However, in the reported
chemical syntheses of Gb3 and isoGb3, the trisaccharide
donors are normally prepared in 17–19 steps due to the
tedious functional group manipulations and glycosylations,
more efficient synthetic routes to the trisaccharide analogues
are still needed. Herein we wish to report a new synthesis
of the methyl glycosides 1a and 1b (Fig. 1), using one-pot
sequential glycosylation strategy.
OH
OBn
OBn
O
OBn
O
OBn
O
HO
+
+
STol
OMe
BzO
BnO
STol
BnO
OBz
3
OBn
4
OBn
2
OH
OH
O
OH
OH
O
OH
HO
O
O
HO
O
OMe
HO
1b
OH
OH
2. Results and discussion
Ph
O
O
OBn
OBn
O
OBn
O
Oligosaccharide synthesis by one-pot sequential glycosyla-
tion strategy6 is one of the efficient routes for saccharide
assembly. Recently many important oligosaccharides such as
fucosyl GM1,7 Globo-H,8 Lewis Y,9 antigen N3 minor glyco-
side,10 and a-Gal epitopes11 have been synthesized using
one-pot method. Promoters play an important role in the one-
pot synthesis. There are many promoters available includ-
ing dimethyl-(thiomethyl)sulfonium triflate (DMTST),12
N-iodosuccinimide/triflic acid (NIS/TfOH),13 phenyl-
sulfenyl chloride and silver triflate (PhSCl/AgOTf),14 and
1-benzenesulfinylpiperidine and triflic anhydride (BSP/
Tf2O),15 but all of them have to be employed under low tem-
perature (ꢀ78 ꢁC to 0 ꢁC) conditions. Very recently, a new
promoter, N-(phenylthio)-3-caprolactam (Fig. 2), has been
reportedbyWong’sgroup.16 Thisreagent canbeused atroom
temperature to promote the glycosyl coupling reactions. We
decided to make the trisaccharides 1a and 1b with this new
promoter by one-pot glycosylation procedure.
O
HO
BnO
+
+
STol
OBz
OMe
HO
STol
BnO
OBn
OBn
2
5
4
Figure 3. The retrosynthesis of trisaccharides 1a and 1b.
Treatment of the peracetylated galactose 6 with thiocresol
in the presence of BF3$Et2O followed by O-deacetylation
with NaOMe afforded compound 7.17 O-Benzylation of 7
provided the desired galactosyl donor 2 in 84% isolated
yield.
The synthesis of galactosyl building block 36a began from
compound 7 in three steps as shown in Scheme 2. Treatment
of 7 with benzaldehyde dimethyl acetal and a catalytic
amount of DL-10-camphorsulfonic acid (CSA) in aceto-
nitrile yielded the 4,6-O-benzylidene derivative 8.18 The
remaining free hydroxyl groups of 8 were benzoylated to
afford fully protected saccharide 9,18 which was subjected
For the synthesis of the target trisaccharides, we chose thio-
glycosides as glycosyl donors because they are stable enough
in storage and can be activated by a variety of promoters
including N-(phenylthio)-3-caprolactam. The retrosynthetic
analysis of 1a and 1b is shown in Figure 3. For the synthesis
of 1a, the perbenzylated thiogalactoside 2 and 2,3-O-
benzoylated-6-O-benzylated thiogalactoside 3 are chosen
as the first and second components, and the methyl glucoside
4 is selected as the third component. For the synthesis of 1b,
thiogalactoside 5 is used as the second building block instead
of 3. All the designed building blocks are very simple with
the widely used benzyl/benzylidene and benzoyl functional-
ities as the hydroxyl protecting groups.
OAc
OAc
O
OH
OBn
OH
O
OBn
O
a,b
c
OAc
AcO
STol
HO
STol
BnO
OAc
OH
7
OBn
2
6
Scheme 1. Synthesis of galactosyl donor 2. Reagents and conditions: (a)
MePhSH, BF3$Et2O, CH2Cl2, 80%; (b) NaOMe, MeOH, 99%; (c) BnBr,
NaH, DMF, 84%.
Ph
Ph
O
OH
O
O
OBn
O
O
c
a
b
O
O
7
STol
STol
d
STol
OBz
BzO
HO
BzO
OBz
3
OH
8
9
The galactosyl donor 26a was prepared from galactose penta-
acetate in a three-step process as shown in Scheme 1.
Ph
O
O
O
STol
OBz
HO
O
S
N
5
Scheme 2. Synthesis of galactosyl donor–acceptors 3 and 5. Reagents and
conditions: (a) benzaldehyde dimethyl acetal, CSA, MeCN, 81%; (b)
BzCl, pyridine, 74%; (c) NaCNBH3, HCl$Et2O, THF, 93%; (d) BzCl,
Ag2O, KI, DCM, 50%.
A
Figure 2. The structure of N-(phenylthio)-3-caprolactam.

C. Wang et al. / Tetrahedron 62 (2006) 11657–11662
11659
to regioselective reductive cleavage by treatment with
NaCNBH3 in the presence of etheral hydrochloride, provid-
ing the acceptor–donor 3 with the 4-OH exposed. On the
other hand, diol 8 was regioselectively benzoylated to obtain
the desired building block 519,6a with the 3-OH free in 50%
isolated yield.
was cleaved with Pd/C catalyzed hydrogenolysis. The target
trisaccharide 1a was obtained in 80% yield from 14.
Similarly, for the synthesis of isoGb3 trisaccharide 1b, we
also checked the two-component coupling reaction of 2
and 5, and we obtained disaccharide 15 in 90% isolated yield
(Scheme 5). After successful preparation of disaccharide 15,
the one-pot sequential glycosylations of building blocks 2
and 5, and methyl glucoside 4 were performed at room tem-
perature, leading to trisaccharide 16 in 50% isolated yield
(Scheme 5). Global deprotection of 16 was carried out in
the same way as above-mentioned to provide the target
trisaccharide 1b in 90% yield.
The synthesis of acceptor 4 (Scheme 3) started from methyl
glucoside 10. After 4,6-O-benzylidenation of 10, the remain-
ing two OH groups of 1120 were benzylated to provide 12.21
Compound 12 was then transformed into the 4-OH free
derivative 422 with NaCNBH3/HCl$Et2O in 90% isolated
yield.
With all these building blocks in hand, glycosylations be-
tween the donors and acceptors were explored. The coupling
reaction of donor 2 and acceptor 3 at room temperature with
N-(phenylthio)-3-caprolactam/Tf2O as the promoter was
firstly tried. Although it was often thought that the 4-OH
of galactose moiety is not easy to couple with glycosyl do-
nors, we successfully obtained the desired disaccharide 13
in 87% isolated yield (Scheme 4). It is also noteworthy
that only the desired a-anomer was obtained in the glycosyl-
ation of 2 with 3. The configuration of the newly formed
glycosidic linkage was confirmed by the 1H NMR coupling
constant of the anomeric proton H-1 (3.5 Hz). The success-
ful preparation of disaccharide 13 indicated that N-(phenyl-
thio)-3-caprolactam/Tf2O can serve as the promoter for
stereoselective glycosylation. We next focused on applying
this promoter to the one-pot synthesis of trisaccharide 14.
Consecutive coupling of p-tolyl thiogalactosides 2 and 3,
and methyl glucoside 4 in dichloromethane at room temper-
ature produced trisaccharide 14 smoothly in 47% isolated
yield (Scheme 4). Finally, global deprotection of 14 was
performed in two steps: the benzoyl group was removed
with NaOMe in methanol, and the benzyl functionality
The structures of 1a and 1b, as well as the correct anomeric
configuration of each glycosidic linkage were confirmed by
their 1H NMR, 13C NMR, and HRMS analyses.
3. Conclusion
In conclusion, the trisaccharide analogues of Gb3 and isoGb3
were synthesized in an efficient way with high stereoselec-
tivity by one-pot sequential glycosylation strategy using
very common building blocks. Importantly, all the glycosyl
coupling reactions were carried out at room temperature in
the presence of N-(phenylthio)-3-caprolactam/Tf2O.
4. Experimental
4.1. General methods
All reactions were carried out under an atmosphere of
nitrogen unless noted otherwise. All solvents were dried
and distilled by standard techniques. Analytical thin-layer
Ph
OBn
O
Ph
OH
O
O
a
b
c
O
HO
HO
O
O
O
HO
O
OMe
OMe
OMe
OBn
OMe
BnO
BnO
HO
OH
OBn
OH
10
11
12
4
Scheme 3. Synthesis of glucosyl acceptor 4. Reagents and conditions: (a) benzaldehyde dimethyl acetal, CSA, MeCN, 80%; (b) BnBr, NaH, DMF, 74%;
(c) NaCNBH3, HCl$Et2O, THF, 90%.
OBn
OBn
O
OBn
OH
OBn
O
BnO
OBn
O
A (1eq) / Tf2O (1eq)
BnO
+
O
STol
STol
STol
BnO
BzO
OBn
O
DCM, 87%
OBn
OBz
STol
BzO
OBz
2
3
13
3(1eq)
4(1eq)
OBn
OBn
O
A (1eq) / Tf2O (1eq)
A (1eq) / Tf2O (1eq)
BnO
DCM
47%
OBn
2
OH
OBn
OH
O
OBn
O
HO
1) NaOMe / MeOH
BnO
HO
O
BnO
O
OH
OBn
OH
O
OBn
O
O
2) Pd/C, H2
80%
O
O
O
HO
BzO
OMe
OMe
OBn
HO
BnO
OH
1a
OBz
OH
14
Scheme 4. Synthesis of Gb3 trisaccharide 1a.

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C. Wang et al. / Tetrahedron 62 (2006) 11657–11662
OBn
OBn
Ph
O
Ph
O
O
OBn
BnO
OBn
O
O
A (1eq) / Tf2O (1eq)
O
O
BnO
+
O
O
STol
STol
BnO
STol
OBz
DCM, 90%
STol
OBz
HO
OBn
15
5
2
5(1eq)
4(1eq)
OBn
OBn
O
A (1eq) / Tf2O (1eq)
A (1eq) / Tf2O (1eq)
BnO
DCM
50%
OBn
2
OH
OH
OBn
Ph
O
OBn
O
O
OH
OH
O
1) NaOMe / MeOH
2) Pd/C, H2
90%
O
HO
OH
O
BnO
OBn
O
O
HO
BnO
O
O
O
OMe
O
HO
OMe
OBn
OH
BnO
OH
OBz
16
1b
Scheme 5. Synthesis of isoGb3 trisaccharide 1b.
chromatography (TLC) was performed on silica gel 60 F254
(E. Merck Co.). Compounds spots were visualized by UV
light and/or by staining with an ethanol solution of phospho-
molybdic acid and cerium sulfate. Column chromatography
was performed on silica gel (200–300 mesh, Qingdao Chem-
ical Industry). NMR spectra were recorded with Varian
INOVA-500 spectrometer. Chemical shifts were referenced
to the internal TMS. Mass spectra were recorded on a PE
SCLEX QSTAR spectrometer.
128.07, 128.19, 128.34, 128.08, 129.50, 129.68, 129.91,
130.07, 133.16, 133.67, 133.98, 138.30, 138.69, 138.87,
165.10, 166.28. HRMS (ESI) Anal. Calcd for C68H66NaO12S
[M+Na]+: 1129.4167; found: 1129.4168.
4.2.2. Methyl 2,3,6-tri-O-benzyl-4-O-[20,30-di-O-benzoyl-
60-O-benzyl-40-O-(200,300,400,600-tetra-O-benzyl-a-D-galacto-
pyranosyl)-b-D-galactopyranosyl]-b-D-glucopyranoside
(14). After a mixture of donor 2 (100.0 mg, 0.155 mmol),
acceptor 3 (90.5 mg, 0.155 mmol), N-(phenylthio)-3-capro-
˚
Optical rotations were measured with an AA-10R automatic
polarimeter.
lactam (34.0 mg, 0.155 mmol) and 4 A molecular sieves
(600.0 mg) in CH2Cl2 (45 mL) was stirred for 2 h at room
temperature, Tf2O (43.7 mg, 0.155 mmol) was added via
a syringe. After 0.5 h, TLC indicated that both the donor
and acceptor were consumed completely, 4 (72.0 mg,
0.155 mmol) and N-(phenylthio)-3-caprolactam (34.0 mg,
0.155 mmol) were then added into the flask. The reaction
mixture was stirred for another 10 min, and Tf2O
(43.7 mg, 0.155 mmol) was added. After stirring for 1 h,
the reaction was quenched with Et3N (0.5 mL) and all insol-
uble materials were removed by filtration. The filtrate was
concentrated and the residue was purified by column chro-
matography on silica gel (petroleum ether/ethyl acetate 5:1
to 2:1) to provide 14 (104.9 mg, 47%) as a thick oil. [a]D20
8.0 (c 0.0025, CHCl3); 1H NMR (500 MHz, CDCl3):
d 2.93–2.96 (m, 1H), 3.26–3.29 (m, 1H), 3.33–3.37 (m,
2H), 3.48 (s, 3H), 3.52–3.62 (m, 4H), 3.68–3.70 (m, 1H),
3.93–4.01 (m, 3H), 4.05–4.07 (m, 3H), 4.10–4.12 (m, 1H),
4.19 (d, 1H, J¼8.0 Hz, H-1), 4.20–4.43 (m, 7H), 4.51–
4.59 (m, 3H), 4.62–4.65 (m, 2H), 4.73 (d, 1H, J¼11.5 Hz),
4.78–4.85 (m, 3H), 4.91 (d, 1H, J¼3.5 Hz, H-100), 4.94 (d,
1H, J¼8.0 Hz, H-10), 5.03–5.07 (m, 2H), 5.74 (dd, 1H,
J¼7.5 Hz, 10.5 Hz), 7.14–7.38 (m, 46H), 7.46–7.49 (m,
1H), 7.86–7.89 (m, 3H); 13C NMR (125 MHz, CDCl3):
d 56.94, 67.40, 67.80, 68.18, 69.48, 70.68, 72.33, 72.87,
73.00, 73.35, 73.74, 74.09, 74.34, 74.72, 74.88, 75.64,
76.24, 79.10, 81.86, 82.33, 100.66, 100.84, 104.44,
127.22, 127.35, 127.44, 127.50, 127.76, 127.89, 127.96,
128.02, 128.12, 128.19, 128.30, 128.42, 129.30, 129.56,
129.83, 133.06, 133.15, 138.19, 138.40, 138.61, 138.76,
138.92, 139.18, 165.15, 166.44. HRMS (ESI) Anal. Calcd
for C89H90NaO18 [M+Na]+: 1469.6019; found: 1469.6013.
4.2. Synthesis
4.2.1. p-Methylphenyl 2,3-di-O-benzoyl-6-O-benzyl-4-O-
(20,30,40,60-tetra-O-benzyl-a-D-galactopyranosyl)-1-thio-
b-D-galactopyranoside (13). To a solution of 2 (100.0 mg,
0.155 mmol), 3 (90.5 mg, 0.155 mmol), and N-(phenyl-
thio)-3-caprolactam (34.0 mg, 0.155 mmol) in CH2Cl2
˚
(45 mL) was added 4 A molecular sieves (600.0 mg). The
mixture was stirred for 2 h at room temperature, and then
Tf2O (43.7 mg, 0.155 mmol) was added. The resulting mix-
ture was stirred at room temperature for 0.5 h. The course of
the reaction was monitored by TLC. Et3N (0.5 mL) was then
added to the mixture. The precipitate was filtered off and the
filtrate was concentrated. The residue was purified by
column chromatography on silica gel (petroleum ether/ethyl
acetate 5:1) to give 13 (137.1 mg, 87%) as a thick oil.
1H NMR (500 MHz, CDCl3): d 2.19 (s, 3H), 2.92–2.95 (m,
1H), 3.33 (t, 1H, J¼9.0 Hz), 3.71–3.74 (m, 1H), 3.87–3.95
(m, 2H), 3.98–4.09 (m, 6H), 4.25–4.30 (m, 2H), 4.39 (d,
1H, J¼2.5 Hz), 4.46 (d, 1H, J¼11.0 Hz), 4.66 (d, 1H,
J¼12.0 Hz), 4.75 (d, 1H, J¼11.5 Hz), 4.79 (d, 1H, J¼
11.5 Hz), 4.83 (d, 1H, J¼11.0 Hz), 4.88 (d, 1H, J¼3.5 Hz,
H-10), 4.90 (d, 1H, J¼11.5 Hz), 5.23 (dd, 1H, J¼2.5 Hz,
10.0 Hz), 5.69 (t, 1H, J¼10.0 Hz), 6.96 (d, 2H, J¼8.0 Hz),
7.18–7.45 (m, 32H, Ar-H), 7.48–7.51 (m, 1H), 7.88–7.90
(m, 2H), 7.94–7.96 (m, 2H); 13C NMR (125 MHz, CDCl3):
d 21.38, 67.66, 68.18, 69.53, 69.63, 72.64, 73.15, 73.33,
74.28, 74.95, 75.18, 75.70, 76.91, 78.54, 78.96, 86.15,
100.21, 127.31, 127.36, 127.45, 127.54, 127.63, 127.94,

C. Wang et al. / Tetrahedron 62 (2006) 11657–11662
11661
4.2.3. Methyl 4-O-[40-O-(a-D-galactopyranosyl)-b-D-gal-
actopyranosyl]-b-D-glucopyranoside (1a). To a solution
of compound 14 (45.0 mg, 0.03 mmol) in MeOH (10 mL)
was added NaOMe/MeOH (30 wt %, 0.4 mL), and the reac-
tion mixture was stirred for 8 h at room temperature. The
mixture was neutralized (H+ resin, weak acid). The resin
was filtered off and the filtrate was concentrated. The result-
ing residue was dissolved in THF/AcOH/H2O (v/v 2:2:1,
10 mL) and then Pd/C (10.0 mg) was added. The reaction
mixture was stirred under H2 atmosphere for 24 h. The
Pd/C was filtered off and the filtrate was concentrated. The
product was purified by C-18 reverse-phase column chro-
matography to give 1a (12.9 mg, 80%) as an oil. [a]2D0 17.7
(600.0 mg) in CH2Cl2 (45 mL) was stirred for 2 h at room
temperature, Tf2O (43.7 mg, 0.155 mmol) was added via a
syringe. After 0.5 h, TLC indicated that both the donor and
acceptorwereconsumedcompletely,4(72.0 mg,0.155 mmol)
and N-(phenylthio)-3-caprolactam (34.0 mg, 0.155 mmol)
were then added. After stirring for another 10 min, Tf2O
(43.7 mg, 0.155 mmol) was added. After stirring for 1 h, the
reaction was quenched with Et3N (0.5 mL) and all insoluble
materials were removed by filtration. The filtrate was concen-
trated and the residue was purified by column chromatography
on silica gel (petroleum ether/ethyl acetate 3:1) to give 16
(103.9 mg, 50%) as a thick oil. [a]2D0 6.2 (c 0.0030, CHCl3);
1H NMR (500 MHz, CDCl3): d 2.97 (s, 1H), 3.16 (dd, 1H,
J¼6.0 Hz, 9.0 Hz), 3.22–3.28 (m, 2H), 3.39 (t, 1H,
J¼7.5 Hz), 3.46–3.48 (m, 5H), 3.60–3.68 (m, 4H), 3.73 (d,
1H, J¼11.0 Hz), 3.79 (dd, 1H, J¼3.5 Hz, 10.0 Hz), 3.84 (t,
1H, J¼6.5 Hz), 3.88–3.91 (m, 1H), 3.94–3.97 (m, 1H),
4.11–4.26 (m, 6H), 4.35 (t, 2H, J¼12.0 Hz), 4.42–4.53 (m,
4H), 4.58–4.63 (m, 2H), 4.69 (d, 1H, J¼6.0 Hz), 4.77–4.86
(m, 4H), 5.04 (d, 1H, J¼3.5 Hz, H-100), 5.10 (d, 1H,
J¼11.0 Hz), 5.32 (s, 1H), 5.61 (dd, 1H, J¼8.5 Hz, 10.0 Hz),
7.06–7.38 (m, 40H), 7.48–7.50 (m, 3H), 7.97–7.99 (m, 2H);
13C NMR (125 MHz, CDCl3): d 56.95, 66.60, 68.36, 68.73,
68.80, 69.84, 71.37, 72.13, 72.26, 73.09, 73.14, 73.22,
74.41, 74.64, 74.68, 74.92, 75.26, 75.48, 75.84, 77.64,
78.58, 81.96, 83.03, 95.55, 100.95, 101.20, 104.48, 126.39,
127.09, 127.29, 127.37, 127.45, 127.49, 127.58, 127.65,
127.81, 127.91, 127.99, 128.09, 128.15, 128.23, 128.34,
128.41, 128.70, 129.76, 129.85, 133.01, 137.77, 138.16,
138.46, 138.60, 138.65, 138.78, 139.07, 164.69. HRMS
(ESI) Anal. Calcd for C82H88NO17 [M+NH4]+: 1358.6047;
found: 1358.6053.
1
(c 0.00338, H2O/CH3OH 1:2); H NMR (500 MHz, D2O):
d 3.27–3.31 (m, 1H), 3.56 (s, 3H), 3.57–3.60 (m, 2H),
3.60–3.64 (m, 2H), 3.67–3.73 (m, 3H), 3.75 (d, 1H,
J¼3.0 Hz), 3.77–3.79 (m, 1H), 3.79–3.87 (m, 4H), 3.87–
3.94 (m, 2H), 4.00 (d, 1H, J¼7.5 Hz), 4.02–4.04 (m, 2H),
4.35 (t, 1H, J¼6.0 Hz), 4.40 (d, 1H, J¼8.0 Hz, H-10), 4.50
(d, 1H, J¼7.5 Hz, H-1), 4.94 (d, 1H, J¼4.0 Hz, H-100);
13C NMR (125 MHz, D2O): d 57.95, 60.76, 61.12, 61.27,
69.31, 69.70, 69.86, 71.57, 71.66, 72.91, 73.62, 75.19,
75.55, 76.17, 78.10, 79.40, 101.05, 103.77, 104.10. HRMS
(ESI) Anal. Calcd for C19H34NaO16 [M+Na]+: 541.1739;
found: 541.1728.
4.2.4. p-Methylphenyl 2-O-benzoyl-4,6-O-benzylidene-3-
O-(20,30,40,60-tetra-O-benzyl-a-D-galactopyranosyl)-1-thio-
b-D-galactopyranoside (15). To a solution of 2 (100.0 mg,
0.155 mmol), 5 (74.1 mg, 0.155 mmol), and N-(phenylthio)-
3-caprolactam (34.0 mg, 0.155 mmol) in CH2Cl2 (45 mL)
˚
was added 4 A molecular sieves (600.0 mg), and the mixture
was stirred for 2 h at room temperature. Tf2O (43.7 mg,
0.155 mmol) was then added, and the reaction mixture was
stirred at room temperature for 0.5 h. The course of the reac-
tion was monitored by TLC. Et3N (0.5 mL) was then added to
the mixture. The precipitate was filtered off and the filtrate was
concentrated. The residue was purified by column chromato-
graphy on silica gel (petroleum ether/ethyl acetate 5:1) to give
4.2.6. Methyl 4-O-[30-O-(a-D-galactopyranosyl)-b-D-gal-
actopyranosyl]-b-D-glucopyranoside (1b). To a solution
of compound 16 (40.2 mg, 0.03 mmol) in MeOH (10 mL)
was added NaOMe/MeOH (30 wt %, 0.4 mL), and the reac-
tion mixture was stirred for 8 h at room temperature. The
mixture was neutralized (H+ resin, weak acid). The resin
was filtered off and the filtrate was evaporated in vacuum.
The resulting residue was dissolved in THF/AcOH/H2O
(v/v 2:2:1, 10 mL) and then Pd/C (10.0 mg) was added.
The reaction mixture was stirred under H2 atmosphere for
24 h. The Pd/C was filtered off and the filtrate was concen-
trated. The product was purified by C-18 reverse-phase
column chromatography to give 1b (13.9 mg, 90%) as an
oil. [a]2D0 20.1 (c 0.00579, H2O/CH3OH 1:2); 1H NMR
(500 MHz, D2O): d 3.29–3.30 (m, 1H), 3.58 (s, 3H), 3.61–
3.63 (m, 1H), 3.65–3.68 (m, 3H), 3.71–3.87 (m, 8H),
3.94–4.02 (m, 3H), 4.18–4.21 (m, 2H), 4.41 (d, 1H,
J¼8.0 Hz, H-1), 4.52 (d, 1H, J¼7.5 Hz, H-10), 5.14 (d, 1H,
J¼4.0 Hz, H-100); 13C NMR (125 MHz, D2O): d 57.98,
60.88, 61.68, 61.74, 65.56, 68.95, 69.89, 70.03, 70.33,
71.59, 73.52, 75.21, 75.49, 75.80, 77.96, 79.38, 96.19,
103.60, 103.83. HRMS (ESI) Anal. Calcd for
C19H34O16Na [M+Na]+: 541.1739; found: 541.1748.
1
15 (134.9 mg, 90%) as an oil. H NMR (500 MHz, CDCl3):
d 2.32 (s, 3H), 3.17–3.25 (m, 2H), 3.41 (s, 2H), 3.63 (dd,
1H, J¼3.0 Hz, 10.0 Hz), 3.82 (t, 1H, J¼6.5 Hz), 3.92–3.96
(m, 2H), 4.00 (dd, 1H, J¼3.0 Hz, 10.0 Hz), 4.25 (d, 1H,
J¼10.5 Hz), 4.31–4.47 (m, 6H), 4.56 (d, 1H, J¼11.5 Hz),
4.62 (d, 1H, J¼12.0 Hz), 4.72 (d, 1H, J¼10.0 Hz, H-1),
4.77 (d, 1H, J¼11.5 Hz), 5.05 (d, 1H, J¼3.5 Hz, H-10), 5.38
(s, 1H), 5.60 (t, 1H, J¼9.5 Hz), 6.96–7.42 (m, 32H, Ar-H),
8.02 (d, 2H, J¼8.0 Hz); 13C NMR (125 MHz, CDCl3):
d 21.25, 68.66, 68.98, 69.34, 69.84, 69.91, 71.80, 72.17,
73.11, 73.23, 74.57, 74.94, 75.53, 75.80, 78.59, 85.44,
94.64, 101.04, 126.55, 127.25, 127.30, 127.38, 127.46,
127.55, 127.66, 127.80, 128.06, 128.10, 128.14, 128.22,
128.29, 128.89, 129.46, 129.81, 130.07, 132.92, 134.16,
137.66, 138.08, 138.28, 138.54, 138.66, 138.80, 164.63. MS
(ESI) Anal. Calcd for C61H64NO11S [M+NH4]+: 1018.4;
found: 1018.7.
4.2.5. Methyl 2,3,6-tri-O-benzyl-4-O-[20-O-benzoyl-40,60-
O-benzylidene-30-O-(200,300,400,600-tetra-O-benzyl-a-D-gal-
actopyranosyl)-b-D-galactopyranosyl]-b-D-glucopyrano-
side (16). After a mixture of donor 2 (100.0 mg, 0.155 mmol),
acceptor 5 (74.1 mg, 0.155 mmol), N-(phenylthio)-3-capro-
Acknowledgements
This work was financially supported by the National Natural
Science Foundation of China, ‘973’ grant from the Ministry
of Science and Technology of China, and Peking University.
˚
lactam (34.0 mg, 0.155 mmol) and 4 A molecular sieves

11662
C. Wang et al. / Tetrahedron 62 (2006) 11657–11662
Y.; Ogawa, T. Carbohydr. Res. 1987, 163, 189–208; (c)
References and notes
Nicolaou, K. C.; Caulfield, T. J.; Kataoka, H.; Kumazawa, T.
J. Am. Chem. Soc. 1988, 110, 7910–7912; (d) Nicolaou,
K. C.; Caulfield, T. J.; Kataoka, H. Carbohydr. Res. 1990,
202, 177–191; (e) Qiu, D.; Schmidt, R. R. Liebigs Ann.
Chem. 1992, 217–224; (f) Hashimoto, S.-I.; Sakamoto, H.;
Honda, T.; Abe, H.; Nakamura, S.-I.; Ikegami, S. Tetrahedron
Lett. 1997, 38, 8969–8972; (g) Bosse, F.; Marcaurelle, L. A.;
Seeberger, P. H. J. Org. Chem. 2002, 67, 6659–6670; (h)
Hsieh, S. Y.; Jan, M. D.; Patkar, L. N.; Chen, C. T.; Lin,
C. C. Carbohydr. Res. 2005, 340, 49–57; (i) Yao, Q.; Song,
J.; Xia, C.; Zhang, W.; Wang, P. G. Org. Lett. 2006, 8, 911–914.
6. (a) Zhang, Z.; Ollmann, I. R.; Ye, X.-S.; Wischnat, R.; Baasov,
T.; Wong, C.-H. J. Am. Chem. Soc. 1999, 121, 734–753; (b) Ye,
X.-S.; Wong, C.-H. J. Org. Chem. 2000, 65, 2410–2431; (c)
Koeller, K. M.; Wong, C.-H. Chem. Rev. 2000, 100, 4465–
4493; (d) Ley, S. V.; Priepke, H. W. M. Angew. Chem., Int.
Ed. Engl. 1994, 33, 2292–2294; (e) Douglas, N. L.; Ley,
S. V.; Lucking, U.; Warriner, S. L. J. Chem. Soc., Perkin
Trans. 1 1998, 51–65; (f) Raghaven, S.; Kahne, D. J. Am.
Chem. Soc. 1993, 115, 1580–1581; (g) Yamada, H.; Harada,
T.; Takahashi, T. J. Am. Chem. Soc. 1994, 116, 7919–7920;
(h) Huang, X.; Huang, L.; Wang, H.; Ye, X.-S. Angew.
Chem., Int. Ed. 2004, 43, 5221–5224; (i) Wang, Y.; Zhang,
L.-H.; Ye, X.-S. Comb. Chem. High Throughput Screen.
2006, 9, 63–75.
1. (a) Hannun, Y. A.; Bell, R. M. Science 1989, 243, 500–507; (b)
Kolter, T.; Sandhoff, K. Angew. Chem., Int. Ed. 1999, 38, 1532–
1568; (c) Cremeti, E. A.; Fischl, S. A. Lipids 2000, 35, 937–945;
(d) Harouse, J. M.; Bhat, S.; Spitalnik, S. L. Science 1991, 253,
320–323; (e) Lourenco, A.; Lobo, A. M.; Rodriguez, B.;
Jimeno, M. L. Phytochemistry 1996, 43, 617–619.
2. (a) Naika, M.; Marcus, D. M. Biochem. Biophys. Res. Commun.
1974, 60, 1105–1111; (b) Wiels, J.; Holmes, E. H.; Cochran,
N.; Tursz, T.; Hakomori, S. J. Biol. Chem. 1984, 259, 14783–
14787; (c) Kannagi, R.; Levery, S. B.; Ishigami, F.;
Hakomori, S.; Shevinsky, L. H.; Knowles, B. B.; Solter, D.
J. Biol. Chem. 1983, 258, 8934–8942; (d) Fukuda, M. N.;
Bothner, B.; Lloyd, K. O.; Rettig, W. J.; Tiller, P. R.; Dell, A.
J. Biol. Chem. 1986, 261, 5145–5153; (e) Kniep, B.; Monner,
D. A.; Schwulera, U.; Muhlradt, P. F. Eur. J. Biochem. 1985,
149, 187–191; (f) Kint, J. A. Science 1970, 167, 1268–1273;
(g) Li, Y.-T.; Li, S.-C. J. Biol. Chem. 1971, 246, 3769–3771.
3. (a) Keusch, G. T.; Jacewicz, M.; Acheson, D. W. K.; Donohue-
Rolfe, A.; Kane, A. V.; McCluer, R. H. Infect. Immun. 1995, 63,
1138–1141; (b) Nyholm, P.-G.; Magnusson, G.; Zheng, Z.;
Norel, R.; Binnington-Boyd, B.; Lingwood, C. A. Chem.
Biol. 1996, 4, 263–275; (c) Fan, E.; Merritt, E. A.; Verlinde,
C. L. M. J.; Hol, W. G. J. Curr. Opin. Struct. Biol. 2000, 10,
680–686; (d) Ling, H.; Boodhoo, A.; Hazes, B.; Cummings,
M. D.; Armstrong, G. D.; Brunton, J. L.; Read, R. J.
Biochemistry 1998, 37, 1777–1788; (e) Shimizu, H.; Field,
R. A.; Homans, S. W.; Donohue-Rolfe, A. Biochemistry
1998, 37, 11078–11082; (f) Stein, P. E.; Boodhoo, A.;
Tyrrell, G. J.; Brunton, J. L.; Read, R. J. Nature 1992, 355,
748–750; (g) Lindberg, A. A.; Brown, J. E.; Stromberg, N.;
Westling-Ryd, M.; Schultz, J. E.; Karlsson, K.-A. J. Biol.
Chem. 1987, 262, 1779–1785.
7. Mong, T. K.-K.; Lee, H.-K.; Duron, S. G.; Wong, C.-H. Proc.
Natl. Acad. Sci. U.S.A. 2003, 100, 797–802.
8. Burkhart, F.; Zhang, Z.; Wacowich-Sgarbi, S.; Wong, C.-H.
Angew. Chem., Int. Ed. 2001, 40, 1274–1277.
9. Mong, K.-K. T.; Wong, C.-H. Angew. Chem., Int. Ed. 2002, 41,
4087–4090.
10. Lee, J.-C.; Wu, C.-Y.; Apon, J. V.; Siuzdak, G.; Wong, C.-H.
Angew. Chem., Int. Ed. 2006, 45, 2753–2757.
11. (a) Wang, Y.; Huang, X.; Zhang, L.-H.; Ye, X.-S. Org. Lett.
2004, 6, 4415–4417; (b) Wang, Y.; Yan, Q.; Wu, J.; Zhang,
L.-H.; Ye, X.-S. Tetrahedron 2005, 61, 4313–4321.
12. Fugedi, P.; Garegg, P. J. Carbohydr. Res. 1986, 149, c9–c12.
13. Konradsson, P.; Udodong, U. E.; Fraser-Reid, B. Tetrahedron
Lett. 1990, 31, 4313–4316.
14. (a) Martichonok, V.; Whitesides, G. M. J. Org. Chem. 1996,
61, 1702–1706; (b) Crich, D.; Sun, S. Tetrahedron 1998, 54,
8321–8348.
15. Crich, D.; Smith, M. J. Am. Chem. Soc. 2001, 123, 9015–9020.
16. Duron, S. G.; Polat, T.; Wong, C.-H. Org. Lett. 2004, 6, 839–
841.
17. Magnusson, G. J. Org. Chem. 1977, 42, 913–914.
18. Vargas-berenguel, A.; Meldal, M.; Paulsen, H.; Jensen, K. J.;
Bock, K. J. Chem. Soc., Perkin Trans. 1 1994, 3287–3294.
19. Wang, H.; She, J.; Zhang, L.-H.; Ye, X.-S. J. Org. Chem. 2004,
69, 5774–5777.
4. (a) Makita, A.; Taniguchi, N. Glycolipids; Wiegand, H., Ed.;
Elsevier: Amsterdam, 1985; pp 1–82; (b) Adga, T.; Yu, R. K.;
Scarsdale, J. N.; Suzuki, M.; Kuroda, Y.; Kitagawa, H.;
Miyatake, T. Biochemistry 1988, 27, 5335–5340; (c) Bock,
K.; Breimer, M. E.; Bdgnole, A.; Hansson, G. C.; Karlsson,
K. A.; Larson, G.; Leffler, H.; Samuelsson, B. E.; Stromberg,
N.; Svanborg-Eden, K.; Thurin, J. J. Biol. Chem. 1985, 260,
8545–8551; (d) Karlsson, K. A. Pure Appl. Chem. 1987, 59,
1447–1448; (e) Ashline, S.; Singh, A.; Hanneman, V. R.
Anal. Chem. 2005, 77, 6250–6262; (f) Zhou, D.; Mattner, J.;
Schrantz, C. N.; Yin, N.; Gao, Y.; Sagiv, Y.; Hudspeth, K.;
Wu, Y.-P.; Yamashita, T.; Teneberg, S.; Wang, D.; Proia,
R. L.; Levery, S. B.; Savage, P. B.; Teyton, L.; Bendelac, A.
Science 2004, 306, 1786–1789; (g) Dale, I. G.; Daniel, G. P.;
Smyth, M. J. Science 2004, 306, 1687–1689; (h) Wuhrer, M.;
Grimm, C.; Dennis, R. D.; Idris, M. A.; Geyer, R.
Glycobiology 2004, 14, 115–126; (i) Teneberg, S.; Alsen, B.;
Angstrom, J.; Winter, H. C.; Goldstein, I. J. Glycobiology
2003, 13, 479–486; (j) Hynes, S. O.; Teneberg, S.; Roche, N.;
Wadstrom, T. Infect. Immun. 2003, 71, 2976–2980.
20. Evans, M. E. Carbohydr. Res. 1972, 21, 473–475.
21. Pennison, J. C.; McGilary, O. I. J. Chem. Soc. 1951, 1616–
1617.
22. Garegg, J.; Hultberg, H.; Wallin, S. Carbohydr. Res. 1982, 108,
97–101.
5. (a) Shapiro, D.; Acher, A. J. Chem. Phys. Lipids 1978, 22, 197–
206; (b) Koike, K.; Sugimoto, M.; Sato, S.; Ito, Y.; Nakahara,