Study on systematizing the synthesis of the a-series ganglioside glycans GT1a, GD1a, and GM1 using the newly developed N-Troc-protected GM3 and GalN intermediates

Article abstract of DOI:10.1016/j.carres.2009.06.009

A first systematic synthesis of the glycan parts of the a-series gangliosides (GT1a, GD1a, and GM1) utilizing the newly developed N-Troc-protected GM3 and galactosaminyl building blocks is described. The key processes, including the assembly of the GM2 se

Full text of DOI:10.1016/j.carres.2009.06.009

Carbohydrate Research 344 (2009) 1453–1463
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Carbohydrate Research
journal homepage: www.elsevier.com/locate/carres
Study on systematizing the synthesis of the a-series ganglioside glycans
GT1a, GD1a, and GM1 using the newly developed N-Troc-protected GM3
and GalN intermediates q
a
a,b,
Tatsuya Komori a, Akihiro Imamura a,b, Hiromune Ando a,b, , Hideharu Ishida , Makoto Kiso
*
*
a Department of Applied Bioorganic Chemistry, Faculty of Applied Biological Sciences, Gifu University, 1-1 Yanagido, Gifu-shi, Gifu 501-1193, Japan
b Institute for Integrated Cell-Material Sciences (iCeMS), Kyoto University, Yoshida Ushinomiya-cho, Sakyo-ku, Kyoto 606-8501, Japan
a r t i c l e i n f o
a b s t r a c t
Article history:
A first systematic synthesis of the glycan parts of the a-series gangliosides (GT1a, GD1a, and GM1) utiliz-
ing the newly developed N-Troc-protected GM3 and galactosaminyl building blocks is described. The key
processes, including the assembly of the GM2 sequence and its conversion into the 3-hydroxy acceptor,
were facilitated mainly by the high degree of participation and chemoselective cleavability of the Troc
group in the galactosaminyl unit. Furthermore, the novel GM2 acceptor served as a good coupling partner
during glycosylation with galactosyl, sialyl galactosyl, and disialyl galactosyl donors, successfully produc-
ing the GM1, GD1a, and GT1a glycans.
Received 28 February 2009
Received in revised form 27 May 2009
Accepted 2 June 2009
Available online 7 June 2009
Dedicated to Professor Dr. Hans Kamerling
on the occasion of his 65th birthday
Ó 2009 Elsevier Ltd. All rights reserved.
Keywords:
a-Series ganglioside
Troc group
GM3 acceptor and GM2 acceptor
Diethylphosphite method
Trichloroacetimidate method
1. Introduction
abundant in nature has been needed. The a-series (GM2,1
GM1,1a,2 GD1a,2a and GT1a3) and b-series (GD2, GT1b, and
There has been explosive growth in the field of glycobiology in
the last two decades. The surfaces of animal cells are covered with
glycolipids whose oligosaccharide chains are positioned outermost
from the cell surface and often function as recognition molecules.
Among the glycolipids, glycosphingolipids (GSLs) are the most
abundant and intriguing molecules. GSLs contribute to the glycoca-
lyx of the cell and provide binding sites for toxins, viruses, and bac-
teria, as well as mediate cell adhesion processes and other
intercellular communication events. Gangliosides are distin-
guished from other GSLs by containing one or more sialic acid res-
idues, which are considered as crucial structural and/or electronic
elements for interplay with biological molecules or receptors on
cells. Since gangliosides are extremely minor constituents in living
organisms and are a huge family composed of diverse congeners at
the functionality level, large quantities of homogeneous ganglio-
sides are not available from natural sources. Therefore, the chem-
ical reconstruction of gangliosides from monosaccharides that are
GQ1b)4 have been synthesized by several approaches, including
those developed by our group, and very recently, the synthesis of
the GP1c glycan has also been achieved.5 However, the synthetic
methods cannot always deliver a large amount of ganglioside for
molecular biology or medicinal studies.
Also, in our earlier reports on the synthesis of GM1, GD1a, and
GT1a,2a,3 the low degree of accessibility of the GM2 tetrasaccharide
acceptor (GM2 acceptor) impeded the efficient assembly of the gly-
can parts, decreasing the overall yields. The critical considerations
in the synthesis of the GM2 acceptor are as follows: (1)
sialylation of the C-30 hydroxyl group of lactose and chromato-
graphic separation of the -sialylated product (GM3 glycan); (2)
a-selective
a
b-selective and efficient incorporation of the galactosamine moiety
into the C-40 hydroxyl group of the GM3 glycan, which is hampered
by the adjacent sialyl moiety; and (3) the manipulation of protect-
ing groups to convert GM2 glycan into the corresponding acceptor.
After completion of the first total syntheses of gangliosides GD1a
and GT1a, our efforts have turned to systematizing the synthesis
of the a-series gangliosides with solutions for the above-men-
tioned synthetic problems aimed at obtaining a sufficient supply
for cross-disciplinary studies. Meanwhile, we have devised a highly
reactive N-Troc-sialyl donor,6 with which we recently demon-
q
Part 150 of the series: Synthetic studies on sialoglycoconjugates. For part 149
see: Ref. 17.
* Corresponding authors. Fax: +81 (58) 293 3452 (H.A.).
E-mail address: hando@gifu-u.ac.jp (H. Ando).
0008-6215/$ - see front matter Ó 2009 Elsevier Ltd. All rights reserved.
doi:10.1016/j.carres.2009.06.009

1454
T. Komori et al. / Carbohydrate Research 344 (2009) 1453–1463
moderate yields (69%, a:b = 59:10) by the coupling of the N-acetyl
HO
RO
HO
O
OH
O
OH
O
sialyl donor 5 and 30,40-diol lactose acceptor 4, which was pro-
moted by NIS–TfOH in MeCN (Scheme 1).1b However, silica gel col-
umn chromatography was repeatedly conducted to separate the
O
OH
O
OH
O
NHAc
OH
HO
AcHN
Si
HO
HO
O
desired a-isomer from an anomeric mixture that also contained a
2,3-en sialic acid derivative, thereby making the GM3 assembly
demanding and insufficient. In contrast, the N-Troc sialyl donor 7
O
O
O
OH
OH
COOH
SE
COOH
HO
OH
improved, not only the yield of GM3 8 (83%, a:b = 69:14) trisaccha-
ride production, but also its chromatographic purification.7
Given the high degree of accessibility of GM3 acceptor 8, we
next examined the design of a linchpin unit, the GM2 acceptor,
which is expected to be readily accessible through the minimum
number of reaction steps and to possess a reactive hydroxyl group
at the C-3 position. Therefore, the structure of the galactosaminyl
OH
HO
O
AcHN
HO HO
1 R = H
(GM1 glycan)
2 R =
(GD1a glycan)
donor (GalN donor) was considered. In the earlier report,1b,2a,3
a
HO
OH
COOH
O
COOH
phthaloyl group was employed as a b-directing functionality with
the combination of a methyl sulfide group as an anomeric leaving
group to establish the GM2 sequence (Scheme 2). That is, N-
phthaloylgalactosaminyl donor 9, which was derived from meth-
ylsulfenyl N-phthaloylgalactosamine in a 61% yield over two reac-
tions, was reacted with GM3 acceptor 6 in the presence of NIS–
TfOH to afford GM2 10 in 68% yield. Then, the GM2 glycan was
converted into the corresponding 3,4-diol acceptor 11 through pro-
tecting group manipulations, including demethylation, dephtha-
loylation, N-acetylation, remethylation, and acid hydrolysis of the
isopropylidene group (57% over six reactions from 6). Next, the
coupling reaction with galactosyl donor 12 afforded GM1 13.2a
Although the C-3 hydroxyl group in the cis-diol system was reac-
tive to fashion the GM1 glycan sequence, the adjacent axial C-4
hydroxyl was also unexpectedly glycosylated, thereby producing
4-O-galactosyl and 3,4-di-O-galactosyl derivatives, 14 and 15, as
competitive products.
HO
3 R =
O
O
AcHN
HO HO
(GT1a glycan)
AcHN
HO
HO
Figure 1. Structure of target glycans 1 (GM1), 2 (GD1a), and 3 (GT1a).
strated an efficient assembly of GM3 glycan.7 Here, we report on
the systematic syntheses of the a-series ganglioside glycans GM1
(1), GD1a (2), and GT1a (3), all of which feature the effective con-
struction of the GM2 glycan and its conversion into the corre-
sponding key acceptor (Fig. 1).
2. Results and discussion
2.1. Lessons from our earlier results, and new synthetic
strategy
2.2. Assembly of a key GM2 unit
Our revised strategy includes using an N-Troc sialyl lactose
acceptor (GM3 acceptor) and novel galactosamine unit that is able
to be glycosidated with a less reactive C-40 hydroxyl group within
the GM3 acceptor to fashion a GM2 glycan and then accept mono-,
di-, and trisaccharyl glycosyl units at the C-3 hydroxyl group in the
next elongation step toward the GM1, GD1a, and GT1a glycans. As
we reported recently, the highly reactive N-Troc sialyl donor 7 im-
proved the efficiency of the production of GM3 glycan.7 In our ori-
ginal method of GM2 synthesis, GM3 acceptor 6 was produced in
In this study, keeping these lessons in mind, a Troc group was
chosen as a stereo-directing element in a novel GalN donor, which
was first utilized in GM2 synthesis by Schmidt and co-workers,1c
due to its compatible deprotection with ester groups present in
the sialic acid residue at the C-30 position after glycosylation. Fur-
thermore, the C-4 hydroxyl group was designed to be protected as
a benzylidene with a C-6 hydroxyl group in order to prevent the
hydroxyl group from over-glycosylation at the next elongation
OBn
O
OBn
HO
O
OSE
BnO
O
OBn
OBn
HO
4
OAc
OAc
CO2Me
AcO
CO2Me
AcO
SPh
O
SMe
O
TrocHN
AcO
7
AcHN
AcO
5
AcO
AcO
NIS, TfOH
MeCN
-40 to -35°C
NIS, TfOH
EtCN-CH2Cl2 (10:1)
-50°C
OAc
CO2Me
AcO
OBn
OBn
O
O
O
O
RHN
AcO
OSE
BnO
O
AcO
OBn
OBn
HO
6 R = Ac (69%, α:β = 59:10)
8 R = Troc (83%, α:β = 69:14)
Scheme 1. Sialylations of the C0-3 hydroxyl group of lactose with N-Ac (5) or N-Troc-sialyl donor (7).

T. Komori et al. / Carbohydrate Research 344 (2009) 1453–1463
1455
6
O
OBz
O
NIS, TfOH
CH2Cl2
0°C
O
SMe
NPhth
68%
9
O
OBz
O
O
O
OBn
O
NPhth
O
OBn
BnO
OSE
AcO
O
AcO
AcHN
O
OBn
O
OBn
CO2Me
10
AcO
OAc
1. LiI, Pyr., reflux, 95%
2. NH2NH2 H2O /EtOH, reflux
3. Ac2O /MeOH
4. CH2N2/ Et2O
5. 80% aq. AcOH
HO
OBz
88% (5 steps)
O
O
HO
OBn
O
NHAc
OBn
O
BnO
O
OSE
AcO
AcO
AcHN
O
O
OBn
OBn
BzO
BnO
CO2Me
11
AcO
OAc
OBz
O
NIS, TfOH
CH2Cl2
RT
SMe
OSE
OBz
12
HO
BzO
BnO
OBz
O
OBz
O
O
O
OBn
O
NHAc
OBz
OBn
O
BnO
AcO
O
AcO
AcHN
O
O
OBn
OBn
CO2Me
13
AcO
OAc
(66 %)
BzO
BnO
BzO
BnO
OBz
O
BzO
BnO
OBz
O
O
OBz
O
O
OBz
O
OBz
OBz
O
OBz
O
HO
NHAc
NHAc
14
15
OBz
Scheme 2. Synthesis of GM1 glycan reported by our group.
stage. Finally, the C-3 hydroxyl group was designed to be tempo-
rally capped with a substituent that is able to be selectively cleaved
among other functionalities within the GM2 tetrasaccharide.
According to the design of the GalN moiety, the preparation of
GalN donor 18 commenced with a known phenylthioglycoside of
N-Trocgalactosamine 16,8 which, upon treatment with PhCH(OMe)2
and p-TsOH in THF–MeCN, was converted into product 17 (Scheme
3). Unexpectedly, compound 17 was hard to dissolve in an apolar
solvent such as CH2Cl2. In order to enhance the solubility, a lipophilic
and selectively cleavable tert-butyldimethylsilyl (TBDMS) group
was chosen to cap the C-3 hydroxyl group. Compound 17 was re-
acted with TBDMSCl in the presence of triethylamine and a catalytic
amount of 4-dimethylaminopyridine (DMAP) in pyridine at room
temperature to afford compound 18 in a high yield (94% from 16).
Novel galactosaminyl donor 18, however, showed insufficient
anomeric selectivity in the model coupling reaction with sialyl-
a
-(2?3)-galactosyl acceptor 196 in the presence of NIS–TfOH9 in
CH2Cl2, as shown in Table 1. The
a/b ratio of glycosyl product 20
ranged from 1:1 to 1:2.4, depending on the reaction temperature.
Presumably, a rigidifying effect is imposed by the benzylidene
group which influences the conformational mobility of the pyra-
nose ring, which is similar to the results reported by Chen and
Kong.10
To improve the poor selectivity of the N-Trocgalactosamine do-
nor, the benzylidene group in compound 18 was reductively
opened by the action of PhBCl2 and Et3SiH11 to furnish a benzyl
group at the C-4 oxygen, and the resulting free hydroxyl group at
the C-6 position was successively acetylated to give another galac-

1456
T. Komori et al. / Carbohydrate Research 344 (2009) 1453–1463
Ph
8
+
21
76%
O
O
a
HO
HO
OH
O
PhCH(OMe)2,
BnO
p-TsOH
OAc
O
NHTroc
17
SPh
NHTroc
HO
SPh
O
R2O
d
THF-MeCN
RT
O
OBn
R1HN
OBn
O
16
O
AcO
BnO
a
OSE
b
AcO
O
O
Ph
c
O
R1HN
OBn
OBn
TBDMSCl
TEA,
DMAP
O
CO2Me
O
AcO
OAc
O
TBDMSO
SPh
NHTroc
1
2
22:
23:
R = Troc, R = TBDMS
Pyr
RT
b (88%)
c (83%)
1
2
R = Ac, R = TBDMS
24: R1 = Ac, R2 = H
94% (2 steps)
18
Scheme 3. Synthesis of novel N-Troc-carrying galactosaminyl donor 18.
Scheme 5. Assembly of GM2 tetrasaccharide 22 and its conversion into the
corresponding acceptor 24. Reagents and conditions: (a) NIS, TfOH, CH2Cl2, 4 Å MS,
ꢀ20 °C, 76%; (b) (i) Zn–Cu, 2:1 AcOH–1,2-dichloroethane, 40 °C; (ii) Ac2O, DMAP,
Pyr. rt, 88% (two steps); (c) TASF, DMF, rt, 83%.
Table 1
Glycosylation of model acceptor 19 with donor 18
HO
O
the action of a zinc–copper couple, and the generated amino
groups were acetylated to yield compound 23 in 88% yield. Next,
O-desilylation was completed by the use of excess tris(dimethyl-
amino)sulfonium difluorotrimethylsilicate (TASF) (10 equiv) in
DMF,12 affording GM2 acceptor 24 in 83% yield (56% over four reac-
tions from compound 8).
OBn
O
AcO
AcO
OMP
O
TrocHN
OBn
18
+
CO Me
2
AcO
AcO
19
NIS
TfOH
MS4Å
2.3. Synthesis of GM1, GD1a, and GT1a glycans
Ph
CH Cl
2
2
As coupling partners for GM2 acceptor 24, a set of mono-, di-,
and trisaccharide glycosyl donors were prepared to construct
GM1, GD1a, and GT1a glycans, respectively (Scheme 6). For the
O
O
O
b
TBDMSO
O
TrocHN
AcO
OBn
O
Ph
AcO
TrocHN
a
O
OMP
c
O
1. PhBCl2, Et3SiH
O
OBn
O
BnO
BnO
AW300, CH2Cl2
-78°C
CO Me
OAc
O
2
AcO
AcO
O
20
BnO
SPh
SPh
2. Ac2O, DMAP
Pyr.
OBz
OBz
26
Entry
Temp (°C)
Yielda (%)
a
/b ratiob
1
2
3
rt
0
ꢀ50
90
81
70
1/1.0
1/1.3
1/2.4
25
85% (2 steps)
a
Isolated yield.
a
AcO
O
OBz
O
b
/b ratio was estimated by 1H NMR spectrum.
AcO
AcO
a
OR
b
O
AcHN
AcO
OBz
CO2Me
tosamine donor 21 (98% over two steps; 92% from compound 16)
(Scheme 4).
OAc
27:
28:
29:
R = H
R = C(NH)CCl3
R = P(OEt)2
The glycosylation of GM3 acceptor 8 was then performed with
donor 21 under conditions similar to those described above
(Scheme 5). According to our expectations, the reaction produced
GM2 tetrasaccharide 22 as a single anomer in a much higher yield
than for the model case of donor 18. Compound 22 then underwent
conversion into the corresponding 3-hydroxy acceptor, compound
24. First, the two Troc groups within compound 22 were cleaved by
a (82%, α/β = 7.7/1)
b (73%, α/β = 1/1.8)
BzO
OBz
O
AcO
AcO
a
O
OR
b
O
AcO
AcO
AcHN
O
OBz
CO2Me
c
O
AcHN
1. PhBCl2, Et3SiH
O
BnO
TBDMSO
AW300, CH2Cl2
-78°C
OAc
O
O
AcO
a (83%, α only)
OAc
30: R = H
31: R = C(NH)CCl3
32: R = P(OEt)2
18
SPh
2. Ac2O, DMAP
Pyr.
b (87%, α/β = 5.5/1)
NHTroc
21
Scheme 6. Preparation of glycosyl donors for the assembly of GM1, GD1a, and GT1a
glycans. Reagents and conditions: (a) CCl3CN, DBU, CH2Cl2, 0 °C to rt; (b) ClP(OEt)2,
DIEA, CH3CN, O °C to RT.
98% (2 steps)
Scheme 4. Conversion of 18 into another galacotsaminyl donor 21.

T. Komori et al. / Carbohydrate Research 344 (2009) 1453–1463
1457
GM1 glycan, the original 3-O-benzyl-4-O-benzoylated galactosyl
1. H2, Pd(OH)2-C
THF- EtOH, 40°C
donor 122a was transformed into the 3,4-di-O-benzylated form
26 to prevent the remote participation of the C-4 benzoyl group
to the b-face of the anomeric carbon during glycosylation. Com-
pound 26 was prepared from known galactose derivative 2513 via
the reductive opening of the benzylidene acetal ring and subse-
quent acetylation of the resulting 6-OH group. As sialyl galactose
(for GD1a) and disialyl galactose (for GT1a) donors, the corre-
sponding diethylphosphite derivatives,14 compounds 29 and 32,
were chosen for the first time, together with known trichloroace-
timidate derivatives 2815 and 31,4e respectively, which were re-
ported by our group. Thus, the suitably protected sialyl galactose
2715 and disialyl galactose 304e were converted into diet-
hylphosphite forms 29 and 32, upon reaction with ClP(OEt)2 and
DIPEA, respectively.
1 2 3
, or
33, 34 or 35
2. NaOMe, MeOH
3. then H2O
Scheme 7. Global deprotection of 33, 34, and 35.
2.4. Conclusions
In conclusion, we first demonstrated a systematic assembly of
the a-series ganglioside glycans GM1, GD1a, and GT1a. From the
results of the connection of newly developed GM3 acceptor 8
and GalN-Troc donors 18 and 21, 4,6-O-benzylidene group in 18
turned out to be a mismatch protecting group for b-selective glyco-
sylation, probably due to its sterically hindering the reaction at the
b face of the anomeric center. Conversely, 6-O-acetyl-4-O-benzyl
protection afforded complete b selectivity, with a high yield of gly-
cosylated product. Furthermore, the suitable choice of Troc and
TBDMS groups for C-2 amino and C-3 hydroxyl protection within
the galactosamine moiety allowed an efficient conversion of GM2
tetrasaccharide 22 into the key pivotal acceptor compound 24,
which then served as a good coupling partner for compounds 26,
29, and 32, leading to a successful synthesis of the GM1, GD1a,
and GT1a glycans.
Final connections between GM2 acceptor 24 and nonreducing
end blocks 26, 28, 29, 31, and 32 were made. The optimized cou-
pling yields with each glycosyl donor are summarized in Table 2.
In all events, glycosylation produced exclusively b-glycosides. In
entry 1, GM1 glycan 33 was obtained in 75% yield by the coupling
of compounds 24 and 26, promoted by NIS–TfOH. In the case of
coupling with sialyl galactosyl donors, the phosphite 29 compared
favorably with the imidate 28; thus, the phosphite 29 provided
GD1a glycan 34 in 60% yield, whilst the imidate 28 provided a
38% yield (entries 2 and 3). This tendency increased in the coupling
of disialyl galactosyl donors. In entry 6, GT1a glycan 35 was ob-
tained in 68% yield when phosphite donor 32 was used. Con-
versely, imidate 31 produced compound 35 in 26% yield.
3. Experimental
Finally, the successfully obtained compounds 33 (GM1 glycan),
34 (GD1a glycan), and 35 (GT1a glycan) were subjected to the
manipulation for global deprotection, including hydrogenolysis
on Pd(OH)2-on-charcoal and O-deacylation16 and saponification,
thereby delivering GM1, GD1a, and GT1a glycans 1, 2, and 3,
respectively (Scheme 7).
3.1. General methods
All reactions were carried out under a positive pressure of ar-
gon, unless otherwise noted. All chemicals were purchased from
commercial suppliers and used without further purification, unless
otherwise noted. Molecular sieves were purchased from Wako
Table 2
2
3
BnO
O
R O
OAc
O
OR
O
d
1
e
O
R O
OBn
O
OBn
O
AcHN
OBz
AcO
BnO
AcO
24
a
26, 28, 29, 31 or 32
+
OSE
b
O
O
c
CH Cl
O
2
2
OBn
AcHN
OBn
CO Me
2
AcO
OAc
33 ~ 35
Entrya
1
Donor (equiv)
Promotor (equiv for donor)
Temp (°C)
Product
Yield (%)
75
26 (2.0)
NIS (2.0)
0
33 R1, R2 = Bn, R3 = Ac
TfOH (0.2)
AcO
AcO
AcHN
f
O
1
=
R
34
2
3
28 (2.0)
29 (2.0)
TMSOTf (0.2)
TMSOTf (0.2)
0
0
38
60
CO Me
2
AcO
OAc
R = Ac, R = Bz
2
3
R2 = Ac, R3 = Bz
AcO
AcO
f
O
AcO
AcHN
AcO
AcHN
O
CO Me
g
2
O
4
5
6
31 (1.5)
32 (2.0)
32 (2.0)
TMSOTf (0.2)
TMSOTf (0.2)
TMSOTf (0.2)
0
0
15
26
46
68
1
R =
35
O
O
AcO
OAc
2
3
R , R = Bz
a
MS 4 Å (entry 1) or AW-300 (entries 2–6) was used as a drying reagent.

1458
T. Komori et al. / Carbohydrate Research 344 (2009) 1453–1463
Chemicals Inc. and dried at 300 °C for 2 h in muffle furnace prior to
use. 1H and 13C NMR spectra were recorded at 300 K with a JEOL
ECA 500/600 spectrometer. Chemical shifts are reported in parts
per million (ppm) downfield from Me4Si. MALDI-TOF mass spectra
were recorded in the positive-ion mode on a Bruker Autoflex with
3.3.1. b Isomer
D +9.5 (c 1.4, CHCl3); 1H NMR (600 MHz, CD3CN): d 7.53–7.23
[a]
(m, 15H, 3Ph), 7.03 and 6.83 (2d, 4H, Ar), 6.02 (d, 1H, J2,NH = 9.6 Hz,
NH-b), 5.82 (d, 1H, J5,NH = 9.6 Hz, NH-c), 5.61 (s, 1H, PhCH), 5.17
(m, 3H, H-7c, 8c, 4c), 4.98 (d, 1H, J1,2 = 7.5 Hz, H-1a), 4.91 (d, 1H,
J1,2 = 8.9 Hz, H-1b), 4.86 and 4.64 (2d, 2H, Jgem = 10.9 Hz, OCH2),
4.85 and 4.56 (2d, 2H, Jgem = 11.6 Hz, OCH2), 4.78 and 4.61 (2d, 2H,
Jgem = 12.3 Hz, OCH2), 4.59 and 4.53 (2d, 2H, Jgem = 11.7 Hz, OCH2),
4.34 (dd, 1H, J2,3 = 10.3 Hz, J3,4 = 2.7 Hz, H-3a), 4.15 (d, 1H,
J3,4 = 2.7 Hz, H-4a), 4.13–3.99 (m, 6H, H-6b, 60b, 9c, 90c, 3b, 4b),
3.97 (near d, 1H, J5,6 = 10.9 Hz, H-6c), 3.90 (m, 4H, H-6a, OMe),
3.80–3.75 (m, 3H, H-5a, 5b, 2b), 3.73 (s, 3H, OMe), 3.67–3.62 (m,
3H, H-60a, 5c, 2a), 2.35 (dd, 1H, Jgem = 13.7 Hz, J3eq,4 = 4.8 Hz, H-
3eq-c), 2.21 (near t, 1H, Jgem = 13.7 Hz, J3ax,4 = 11.6 Hz, H-3ax-c),
the use of
a-cyano-4-hydroxy-cinnamic acid (CHCA) as a matrix.
Specific rotations were determined with a Horiba SEPA-300 high-
sensitive polarimeter. Silica gel (300 mesh) manufactured by Fuji
Silysia Co. was used for flash column chromatography. TLC analysis
was conducted on E. Merck TLC (Silica Gel 60-F254 on glass plates).
Compounds were visualized either by exposure to UV light or by
spraying with a solution of 10% H2SO4 in EtOH followed by heating.
Organic solutions were concentrated by rotary evaporation below
40 °C under reduced pressure. Solvent systems in chromatography
are specified in v/v.
t
2.17, 2.07, 1.95 and 1.83 (4s, 12H, 4Ac), 0.89 (s, 9H, Bu), 0.17 and
0.15 (2s, 6H, SiMe2); 13C NMR (150 MHz, CD3CN): d 171.1, 170.6,
170.6, 170.5, 169.8, 156.2, 155.7, 155.1, 152.4, 139.7, 139.7, 139.6,
138.8, 129.8, 129.8, 129.2, 129.2, 129.1, 129.1, 128.7, 128.5, 128.4,
128.4, 127.2, 126.2, 119.0, 115.5, 103.0, 102.9, 101.5, 100.5, 96.7,
96.5, 79.2, 78.9, 77.0, 76.3, 76.0, 75.1, 74.9, 74.0, 73.8, 73.3, 72.1,
70.3, 70.0, 69.8, 68.8, 67.7, 67.0, 62.8, 56.1, 55.5, 54.1, 51.6, 35.3,
26.1, 21.4, 21.3, 21.0, 20.9, 20.9, 18.7, ꢀ4.2, ꢀ4.5; MALDI-TOFMS:
calcd for [C70H86Cl6N2O26Si+Na]+: m/z 1631.32. Found: m/z 1631.32.
3.2. Phenyl 4,6-O-benzylidene-3-O-tert-butyldimethylsilyl-2-
deoxy-1-thio-2-(2,2,2-trichloroethoxycarbamoyl)-b-D-
galactopyranoside (18)
To a solution of compound 16 (2.0 g, 4.47 mmol) in 2:5 THF–
MeCN (28 mL) were added benzaldehyde dimethylacetal (2.0 mL,
13.4 mmol) and p-TsOH (170 mg, 0.900 mmol), and the mixture
was stirred at room temperature for 1 h, with monitoring of the
reaction by TLC (5:1 CHCl3–MeOH). The mixture was neutralized
with Et3N and concentrated. The residue was dissolved in pyridine
(20 mL), and Et3N (1.9 mL, 13.4 mmol), DMAP (600 mg,
4.92 mmol), and TBDMSCl (2.0 g, 13.4 mmol) were added. The
reaction mixture was stirred at room temperature for 4 h, with
monitoring of the reaction by TLC (1:4 EtOAc–toluene). Then
MeOH was added at 0 °C, the reaction mixture was co-evaporated
with toluene, and diluted with CHCl3. The organic layer was
washed with 2 M HCl, H2O, satd NaHCO3, and brine, dried over
Na2SO4, and concentrated. The residue was purified by column
chromatography on silica gel (1:4 EtOAc–hexane) to give 18
3.3.2.
a
Isomer
[a]
D +27.5 (c 1.0, CHCl3); 1H NMR (600 MHz, CDCl3): d 7.55–7.16
(m, 15H, 3Ph), 7.02 and 6.79 (2d, 4H, Ar), 5.61 (m, 1H, J7,8 = 8.2 Hz,
J8,9 = 5.4 Hz, H-8c), 5.53 (s, 1H, PhCH), 5.49 (d, 1H, J2,NH = 10.2 Hz,
NH-b), 5.39 (dd, 1H, J6,7 = 2.7 Hz, J7,8 = 8.2 Hz, H-7c), 5.06 (d, 1H,
J1,2 = 3.4 Hz, H-1b), 5.04 (d, 1H, J1,2 = 6.8 Hz, H-1a), 4.92 and 4.85
(2d, 2H, Jgem = 13.0 Hz, OCH2), 4.91 (m, 1H, H-4c), 4.89 and 4.46
(2d, 2H, Jgem = 11.6 Hz, OCH2), 4.80 (d, 1H, J5,NH = 9.6 Hz, NH-c),
4.77 and 4.51 (2d, 2H, Jgem = 12.3 Hz, OCH2), 4.51 and 4.43 (2d, 2H,
Jgem = 11.6 Hz, OCH2), 4.33 (td, 1H, J1,2 = 3.4 Hz, J2,3 = J2,NH = 10.2 Hz,
H-2a), 4.30 (m, 2H, H-3a, 9c), 4.24 (near d, 1H, Jgem = 11.6 Hz, H-
6b), 4.07 (d, 1H, J3,4 = 2.7 Hz, H-4b), 4.02 (dd, 1H, Jgem = 13.0 Hz,
J8,9 = 5.4 Hz, H-90c), 3.99 (near d, 1H, Jgem = 11.6 Hz, H-60b), 3.96 (s,
1H, H-5b), 3.95 (dd, 1H, J2,3 = 10.2 Hz, J3,4 = 2.7 Hz, H-3b), 3.91 (dd,
1H, J5,6 = 10.9 Hz, J6,7 = 2.7 Hz, H-6c), 3.76 (m, 9H, H-4a, 5a, 5c,
2OMe), 3.63 (m, 2H, H-2a, 6a), 3.58 (dd, 1H, Jgem = 9.6 Hz,
J5,6 = 6.1 Hz, H-60a), 2.56 (dd, 1H, Jgem = 12.3 Hz, J3eq,4 = 4.8 Hz, H-
3eq-c), 2.12, 2.03, 1.96 and 1.85 (4s, 12H, 4Ac), 1.85 (t, 1H, Jgem = -
(2.7 g, 94%); [
a
]
ꢀ8.5 (c 0.44, CHCl3); 1H NMR (600 MHz, CDCl3):
D
d 7.62–7.18 (m, 10H, 2Ph), 5.51 (s, 1H, PhCH), 5.24 (d, 1H, NH),
5.08 (d, 1H, J1,2 = 7.5 Hz, H-1), 4.73 and 4.63 (2d, 2H, Jgem = 12.3 Hz,
OCH2), 4.38 (dd, 1H, Jgem = 12.3 Hz, H-6), 4.35 (br d, 1H, H-3), 4.08
(d, 1H, H-4), 4.02 (d, 1H, Jgem = 12.3 Hz, H-60), 3.56 (m, 1H, H-2),
t
3.54 (s, 1H, H-5), 0.84 (s, 9H, Bu), 0.05 and 0.03 (2s, 6H, SiMe2);
13C NMR (150 MHz, CDCl3): d 153.4, 137.9, 132.9, 132.1, 128.8,
128.8, 128.0, 127.7, 126.2, 100.7, 95.2, 84.3, 76.3, 74.5, 70.7, 70.0,
69.4, 53.3, 25.6, 18.0, ꢀ4.5, ꢀ4.6; MALDI-TOFMS: calcd for
[C28H36Cl3NO6SSi+Na]+: m/z 670.09. Found: m/z 670.15.
t
J3ax,4 = 12.3 Hz, H-3ax-c), 0.87 (s, 9H, Bu), 0.08 and 0.07 (2s, 6H,
SiMe2); 13C NMR (150 MHz, CDCl3): d 170.6, 170.1, 170.1, 169.9,
167.8, 155.4, 154.1, 154.0, 151.3, 139.2, 137.8, 137.7, 137.5, 128.9,
128.6, 128.3, 128.1, 128.0, 128.0, 127.7, 127.5, 127.4, 127.2, 126.1,
125.2, 119.2, 118.6, 114.4, 103.1, 100.5, 99.2, 97.2, 95.3, 95.2, 76.4,
74.9, 74.6, 74.5, 74.2, 73.0, 72.9, 72.0, 71.8, 69.4, 68.9, 68.7, 68.3,
67.3, 67.0, 66.5, 63.0, 62.1, 55.5, 53.0, 52.2, 51.2, 37.5, 25.5, 21.4,
21.3, 20.8, 20.6, 20.4, 18.0, ꢀ4.2, ꢀ4.5; MALDI-TOFMS: calcd for
[C70H86Cl6N2O26Si+Na]+: m/z 1631.32. Found: m/z 1631.31.
3.3. 4-Methoxyphenyl 4,6-O-benzylidene-3-O-tert-butyldimeth-
ylsilyl-2-deoxy-2-(2,2,2-trichloroethoxycarbamoyl)-
pyranosyl-(1?4)-{methyl 4,7,8,9-tetra-O-acetyl-3,5-dideoxy-5-
(2,2,2-trichloroethoxycarbamoyl)- -glycero- -galacto-2-nonu-
-galactopyranoside
D-galacto-
D
a-D
lopyranosylonate-(2?3)}-2,6-di-O-benzyl-b-
D
(20)
3.4. Phenyl 6-O-acetyl-4-O-benzyl-3-O-tert-butyldimethylsilyl-
A suspension of compound 18 (60 mg, 93
lmol), compound 19
2-deoxy-1-thio-2-(2,2,2-trichloroethoxycarbamoyl)-b-D-
(50 mg, 46
(1.5 mL) was stirred at room temperature for 1 h. To the mixture
was added NIS (42 mg, 186 mol). After the mixture was cooled
to ꢀ50 °C, TfOH (1.6 L, 18 mol) was added. The reaction mixture
l
mol), and 4 Å molecular sieves (120 mg) in dry CH2Cl2
galactopyranoside (21)
l
A suspension of compound 18 (111 mg, 171 lmol) and AW-300
molecular sieves (256 mg) in dry CH2Cl2 (2.0 mL) was stirred at
room temperature for 3 h. After the mixture was cooled to
l
l
was stirred at ꢀ50 °C for 1.5 h, with monitoring of the reaction by
TLC (1:2 EtOAc–toluene). Et3N was added to quench the reaction.
The mixture was filtered through Celite. The combined filtrate
and washings were diluted with CHCl3, and the organic layer was
washed with satd NaHCO3, satd Na2S2O3, and brine, dried over
Na2SO4, and concentrated. The residue was purified by column
chromatography on silica gel (1:6 EtOAc–toluene) to give 20
ꢀ78 °C, Et3SiH (82
lL, 513 lmol) and PhBCl2 (75 lL, 581 lmol)
were added, and the mixture was stirred at ꢀ78 °C for 1 h, with
monitoring of the reaction by TLC (1:3 EtOAc–toluene). Et3N and
MeOH were added to quench the reaction. The mixture was filtered
through Celite. The combined filtrate and washings were diluted
with CHCl3, and the organic layer was washed with satd NaHCO3
and brine, dried over Na2SO4, and concentrated. The residue was
(52 mg, 70%) as an anomeric mixture (a:b = 1:2.4).

T. Komori et al. / Carbohydrate Research 344 (2009) 1453–1463
1459
dissolved in pyridine (2.0 mL), Ac2O (0.8 mL) and a catalytic
amount of DMAP were added, and the mixture was stirred at room
temperature for 1 h. Then MeOH was added at 0 °C, the reaction
mixture was co-evaporated with toluene, and diluted with CHCl3.
The organic layer was washed with 2 M HCl, H2O, satd NaHCO3,
and brine, dried over Na2SO4, and concentrated. The residue was
purified by column chromatography on silica gel (1:5 EtOAc–hex-
3.6. 2-(Trimethylsilyl)ethyl 2-acetamido-6-O-acetyl-4-O-benzyl-
3-O-tert-butyldimethylsilyl-2-deoxy-b- -galactopyranosyl-
(1?4)-{methyl 5-acetamido-4,7,8,9-tetra-O-acetyl-3,5-dideoxy-
-glycero- -galacto-2-nonulopyranosylonate-(2?3)}-2,6-
di-O-benzyl-b- -galactopyranosyl-(1?4)-2,3,6-tri-O-benzyl-
b- -glucopyranoside (23)
D
D
a-D
D
D
ane) to give 21 (116 mg, 98%); [
a]
ꢀ2.0 (c 0.52, CHCl3); 1H NMR
To a solution of compound 22 (127 mg, 61 lmol) in 2:1 AcOH–
D
(600 MHz, CDCl3): d 7.51–7.19 (m, 10H, 2Ph), 5.06–5.01 (m, 3H,
H-1, NH, OCH2), 4.73 and 4.64 (2d, 2H, Jgem = 11.7 Hz, OCH2), 4.53
(d, 1H, Jgem = 11.7 Hz, OCH2), 4.25 (dd, 1H, Jgem = 11.7 Hz, H-6),
4.14 (dd, 1H, Jgem = 11.7 Hz, H-60), 4.07 (br d, 1H, H-3), 3.81 (q,
1H, H-2), 3.72 (t, 1H, H-5), 3.70 (d, 1H, H-4), 2.01 (s, 3H, Ac), 0.91
(s, 9H, tBu), 0.15 and 0.09 (2s, 6H, SiMe2); 13C NMR (150 MHz,
CDCl3): d 170.6, 153.6, 138.2, 133.3, 131.9, 128.7, 128.2, 127.6,
127.6, 127.4, 95.1, 85.7, 76.6, 76.0, 75.0, 74.7, 73.8, 63.5, 54.0,
25.7, 20.7, 17.9, ꢀ3.9, ꢀ5.0; MALDI-TOFMS: calcd for
[C30H40Cl3NO7SSi+Na]+: m/z 714.12. Found: m/z 714.15.
1,2-dichloroethane (3.0 mL) was added Zn–Cu couple (665 mg).
The suspension was vigorously stirred at 40 °C for 1.5 h and moni-
tored by TLC (20:1 CHCl3–MeOH). The mixture was filtered through
Celite. The combined filtrate and washings were evaporated and di-
luted with CHCl3, and the organic layer was washed with satd
Na2CO3 and brine, dried over Na2SO4, and concentrated. The residue
was dissolved in pyridine (1.5 mL), Ac2O (0.5 mL) and a catalytic
amount of DMAP were added at 0 °C, and the resulting mixture
was stirred at room temperature for 16 h. Then MeOH was added
at 0 °C, and the reaction mixture was co-evaporated with toluene
and diluted with CHCl3. The organic layer was washed with 2 M
HCl, H2O, satd NaHCO3, and brine, dried over Na2SO4, and concen-
trated. The residue was purified by column chromatography on sil-
3.5. 2-(Trimethylsilyl)ethyl 6-O-acetyl-4-O-benzyl-3-O-tert-
butyldimethylsilyl-2-deoxy-2-(2,2,2-trichloroethoxycarbam-
oyl)-b-
acetyl-3,5-dideoxy-5-(2,2,2-trichloroethoxycarbamoyl)-
glycero- -galacto-2-nonulopyranosylonate-(2?3)}-2,6-di
-O-benzyl-b- -galactopyranosyl-(1?4)-2,3,6-tri-O-benzyl-
b- -glucopyranoside (22)
D
-galactopyranosyl-(1?4)-{methyl 4,7,8,9-tetra-O-
ica gel (50:1 CHCl3–MeOH) to give 23 (98 mg, 88%); [a] +17.2 (c
D
D-
0.93, CHCl3); Ratio of rotamer A:B: 1.65:1 (CDCl3), 2.77:1 (THF-d8),
10.9:1 (CD3CN), 12.0:1 (DMSO-d6); rotamer A: 1H NMR (500 MHz,
CD3CN): d 7.43–6.75 (m, 30H, 6Ph), 6.34 (d, 1H, NH-d), 6.11 (d, 1H,
J5,NH = 10.0 Hz, NH-c), 5.21 (d, 1H, H-7c), 5.14–5.08 (m, 2H, H-4c,
8c), 5.02 and 4.60 (2d, 2H, Jgem = 11.5 Hz, OCH2), 4.87 and 4.58 (2d,
2H, Jgem = 9.5 Hz, OCH2), 4.82 and 4.74 (2d, 2H, Jgem = 11.5 Hz,
OCH2), 4.76 and 4.53 (2d, 2H, Jgem = 11.5 Hz, OCH2), 4.74 (d, 1H,
J1,2 = 10.9 Hz, H-1d), 4.48 and 4.40 (2d, 2H, Jgem = 11.5 Hz, OCH2),
4.46 (d, 1H, J1,2 = 8.0 Hz, H-1b), 4.36 (d, 1H, J1,2 = 8.5 Hz, H-1a),
4.29–4.25 (m, 2H, H-2d, OCH2), 4.21 (d, 2H, H-6d, 60d), 4.11–4.04
(m, 6H, H-3b, 9c, 90c, 3d, 5d, OCH2), 4.02 (q, 1H, J5,NH = 10.0 Hz,
H-5c), 3.93–3.87 (m, 6H, H-6c, 4d, COOMe, CH2CH2SiMe3), 3.78
(t, 1H, H-4a), 3.76 (br s, 1H, H-4b), 3.67 (dd, 1H, H-6b), 3.62–3.55
(m, 3H, H-6a, 60b, CH2CH2SiMe3), 3.49 (t, 1H, H-3a), 3.46 (t, 1H,
H-5b), 3.43 (m, 1H, H-5a), 3.37 (t, 1H, J1,2 = 8.0 Hz, H-2b), 3.28 (dd,
1H, H-60a), 3.10 (t, 1H, J1,2 = 8.5 Hz, H-2a), 2.32 (dd, 1H,
Jgem = 14.5 Hz, H-3eq-c), 2.20 (t, 1H, Jgem = 14.5 Hz, H-3ax-c), 2.18,
2.07, 1.94, 1.91, 1.87, 1.85, 1.78 (7s, 21H, 7Ac), 0.94 (m, 2H,
CH2CH2SiMe3), 0.93 (s, 9H, tBu), 0.22 and 0.20 (2s, 6H, SiMe2), 0.00
(s, 9H, CH2SiMe3); 13C NMR (125 MHz, CD3CN): d 171.3, 171.2,
170.8, 170.7, 170.5, 170.3, 170.2, 170.0, 140.2, 140.1, 139.7, 139.6,
139.6, 130.3, 129.3, 129.2, 129.1, 129.1, 129.0, 128.9, 128.9, 128.7,
128.5, 128.5, 128.4, 128.3, 128.2, 128.0, 104.0, 103.5, 102.8, 100.7,
83.2, 82.5, 79.9, 78.7, 76.8, 76.4, 76.3, 76.1, 75.8, 75.4, 75.3, 75.0,
74.4, 73.7, 73.6, 72.4, 70.7, 70.6, 69.0, 67.6, 67.3, 64.4, 62.3, 54.0,
49.2, 35.0, 26.3, 26.2, 24.1, 23.1, 21.3, 21.1, 21.0, 20.9, 20.8, 18.9,
18.5, ꢀ1.3, ꢀ3.8, ꢀ4.5; MALDI-TOFMS: calcd for [C95H126N2O29Si2+
Na]+: m/z 1837.78. Found: m/z 1837.70.
a
-D
D
D
A suspension of compound 21 (116 mg, 167
(126 mg, 84 mol), and 4 Å molecular sieves (262 mg) in dry CH2Cl2
(2.5 mL) was stirred at room temperature for 1 h. To the mixture
was added NIS (75 mg, 334 mol). After the mixture was cooled to
ꢀ20 °C, TfOH (3.0 L, 33 mol) was added, and the reaction mixture
lmol), compound 8
l
l
l
l
was stirred at ꢀ20 °C for 1.5 h, with monitoring of the reaction by
TLC (1:3 EtOAc–toluene). Et3N was added to quench the reaction.
The mixture was filtered through Celite. The combined filtrate and
washings were diluted with CHCl3, and the organic layer was washed
with satd NaHCO3, satd Na2S2O3, and brine, dried over Na2SO4, and
concentrated. The residue was purified by column chromatography
on silica gel (1:6 EtOAc–toluene) to give 22 (132 mg, 76%); [a D
]
+12.7 (c 1.1, CHCl3); Ratio of rotamer A:B: 2.06:1 (CDCl3), 3.72:1 (ace-
tone-d6), 6.76:1 (THF-d8), 10.5:1 (CD3CN); rotamer A: 1H NMR
(600 MHz, CD3CN): d 7.44–6.74 (m, 30H, 6Ph), 5.80 (d, 1H,
NH-c), 5.68 (d, 1H, NH-d), 5.26 (d, 1H, H-7c), 5.16 (td, 1H,
J3eq,4 = 5.4 Hz, H-4c), 5.11 (m, 1H, H-8c), 5.05 and 4.62 (2d, 2H,
Jgem = 11.0 Hz, OCH2), 4.87 and 4.56 (2d, 2H, Jgem = 9.6 Hz, OCH2),
4.81 (d, 1H, J1,2 = 10.9 Hz, H-1d), 4.80–4.75 (m, 5H, 5OCH2), 4.61 (d,
1H, OCH2), 4.57–4.55 (m, 2H, 2OCH2), 4.49 and 4.42 (2d, 2H,
Jgem = 12.3 Hz, OCH2), 4.47 (d, 1H, J1,2 = 9.6 Hz, H-1b), 4.36 (d, 1H,
J1,2 = 7.5 Hz, H-1a), 4.32 (d, 1H, OCH2), 4.22 (m, 2H, H-6d, 60d), 4.18–
4.02 (m, 7H, H-3b, 9c, 90c, 2d, 3d, 5d, OCH2), 3.95–3.88 (m, 6H, H-6c,
4d, COOMe, CH2CH2SiMe3), 3.82 (t, 1H, H-4a), 3.79 (br s, 1H, H-4b),
3.69 (dd, 1H, H-6b), 3.66–3.58 (m, 4H, H-6a, 60b, 5c, CH2CH2SiMe3),
3.49–3.41 (m, 4H, H-3a, 5a, 2b, 5b), 3.33 (dd, 1H, H-60a), 3.10 (t, 1H,
J1,2 = 7.5 Hz, H-2a), 2.33 (dd, 1H, Jgem = 13.7 Hz, J3eq,4 = 5.4 Hz, H-3eq-
c), 2.20 (t, 1H, Jgem = 13.7 Hz, H-3ax-c), 2.13, 2.08, 1.90, 1.89, 1.88
(5s, 15H, 5Ac), 0.95 (m, 2H, CH2CH2SiMe3), 0.91 (s, 9H, tBu), 0.24 and
0.22 (2s, 6H, SiMe2), 0.00 (s, 9H, CH2SiMe3); 13C NMR (125 MHz,
CD3CN): d 171.2, 170.7, 170.5, 170.3, 170.2, 155.4, 155.1, 140.2,
140.0, 139.6, 139.6, 139.6, 130.3, 129.8, 129.3, 129.1, 129.1, 129.0,
128.9, 128.9, 128.7, 128.7, 128.5, 128.5, 128.4, 128.4, 128.3, 128.3,
128.3, 128.1, 128.1, 126.2, 103.5, 102.6, 100.7, 96.7, 96.6, 83.3, 82.5,
80.0, 79.6, 78.6, 76.5, 76.4, 76.3, 76.1, 76.1, 75.4, 75.2, 75.1, 75.0,
74.8, 74.4, 73.7, 73.6, 72.5, 71.8, 70.7, 70.2, 69.0, 67.6, 67.1, 64.4,
62.1, 55.9, 54.4, 51.6, 34.9, 26.3, 21.4, 21.3, 21.1, 21.0, 20.9,
20.9, 18.9, 18.5, ꢀ1.3, ꢀ3.9, ꢀ4.4; MALDI-TOFMS: calcd for
[C97H124Cl6N2O31Si2+ Na]+: m/z 2101.57. Found: m/z 2101.85.
3.7. 2-(Trimethylsilyl)ethyl 2-acetamido-6-O-acetyl-4-O-benzyl-
2-deoxy-b-
tetra-O-acetyl-3,5-dideoxy-
anosylonate-(2?3)}-2,6-di-O-benzyl-b-
(1?4)-2,3,6-tri-O-benzyl-b- -glucopyranoside (24)
D
-galactopyranosyl-(1?4)-{methyl 5-acetamido-4,7,8,9-
-glycero- -galacto-2-nonulopyr-
-galactopyranosyl-
D
a-D
D
D
To compound 23 (34 mg, 19
was added TASF (52 mg, 187
l
mol) in a round-bottomed flask
l
mol) in DMF (0.8 mL), and the
resulting mixture was stirred at room temperature for 1.5 h. The
progress of the reaction was monitored by TLC (20:1 CHCl3–
MeOH). The reaction mixture was extracted with CHCl3, and the
organic layer was washed with H2O, satd NaHCO3, and brine, dried
over Na2SO4, and concentrated. The residue was purified by col-
umn chromatography on silica gel (25:25:1 EtOAc–toluene–
MeOH) to give 24 (27 mg, 83%); [
a
]
D
ꢀ12.2 (c 0.46, CHCl3);

1460
T. Komori et al. / Carbohydrate Research 344 (2009) 1453–1463
1H NMR (600 MHz, CDCl3): d 7.43–6.89 (m, 30H, 6Ph), 7.11 (d, 1H,
NH-d), 5.28 (d, 1H, OH-3d), 5.25 (d, 1H, H-7c), 5.19–5.17 (m, 2H,
H-8c, NH-c), 5.11 and 4.71 (2d, 2H, Jgem = 11.7 Hz, OCH2), 5.07
(td, 1H, H-4c), 4.91 and 4.79 (2d, 2H, Jgem = 11.0 Hz, OCH2), 4.90
and 4.75 (2d, 2H, Jgem = 9.6 Hz, OCH2), 4.84 and 4.49 (2d, 2H,
Jgem = 11.7 Hz, OCH2), 4.73 (d, 1H, J1,2 = 8.2 Hz, H-1d), 4.59 and
4.49 (2d, 2H, Jgem = 11.7 Hz, OCH2), 4.49 (d, 1H, J1,2 = 7.5 Hz,
H-1b), 4.38 (d, 1H, J1,2 = 8.2 Hz, H-1a), 4.26–4.17 (m, 5H, H-2d,
6d, 60d, OCH2), 4.08 (dd, 1H, H-9c), 4.02–3.95 (m, 6H, H-5c, 6c,
90c, 4d, 5d, CH2CH2SiMe3), 3.94–3.91 (m, 2H, H-4a, 3b), 3.84
(s, 3H, COOMe), 3.80–3.77 (m, 3H, H-6a, 4b, 3d), 3.72 (dd, 1H,
H-60a), 3.68 (m, 1H, H-6b), 3.59 (m, 1H, CH2CH2SiMe3), 3.57 (t,
1H, H-3a), 3.48 (t, 1H, J1,2 = 7.5 Hz, H-2b), 3.42 (m, 1H, H-5a),
3.38–3.35 (m, 3H, H-2a, 60b, 5b), 2.24 (m, 2H, H-3eq-c, 3-ax-c),
2.06, 2.02, 1.98, 1.96, 1.91, 1.88 and 1.86 (7s, 21H, 7Ac), 1.03 (m,
2H, CH2CH2SiMe3), 0.00 (s, 9H, CH2SiMe3); 13C NMR (150 MHz,
CDCl3): d 173.1, 170.5, 170.3, 170.2, 169.5,169.1, 168.0, 138.7,
138.6, 138.5, 138.4, 138.2, 137.8, 128.6, 128.3, 128.2, 128.2,
128.1, 127.9, 127.5, 127.5, 127.4, 127.4, 127.3, 127.2, 102.9,
102.4, 101.7, 99.3, 82.5, 81.9, 78.8, 78.3, 77.0, 76.6, 76.2, 75.8,
75.6, 75.3, 75.3, 75.1, 74.9, 73.4, 73.3, 73.2, 72.3, 71.6, 68.8, 68.6,
68.5, 67.7, 67.2, 66.4, 63.1, 61.5, 55.4, 53.1, 49.0, 35.3, 29.6, 23.1,
22.7, 20.9, 20.7, 20.6, 20.4, 20.4, 18.4, ꢀ1.4; MALDI-TOFMS: calcd
for [C89H112N2O29Si+Na]+: m/z 1723.70. Found: m/z 1723.40.
(15:1 CHCl3–MeOH). After completion of the reaction, the solvent
was evaporated, and the resulting residue was purified by column
chromatography on silica gel (60:1 CHCl3–MeOH) to give 29
(98 mg, 73%,
a
:b = 1:1.8); 1H NMR (500 MHz, CDCl3): b isomer; d
8.15 and 8.05 (2d, 4H, Ph), 7.62–7.15 (m, 6H, Ph), 5.61 (m, 1H,
H-8b), 5.38 (d, 1H, J1,2 = 9.0 Hz, H-1a), 5.38 (t, 1H, H-2a), 5.19
(dd, 1H, H-7b), 5.14 (d, 1H, H-4a), 4.99 (d, 1H, J5,NH = 10.0 Hz,
NH-b), 4.91–4.81 (m, 2H, H-3a, 4b), 4.44 (dd, 1H, Jgem = 11.0 Hz,
H-6a), 4.29 (dd, 1H, Jgem = 12.5 Hz, H-9b), 4.25 (dd, 1H,
Jgem = 11.0 Hz, H-60a), 4.16 (t, 1H, H-5a), 3.96 (dd, 1H, Jgem = 12.5 Hz,
H-90b), 3.77 (s, 3H, COOMe), 3.65–3.54 (m, 3H, H-6b, 2CH2CH3),
2.56 (dd, 1H, Jgem = 12.6 Hz, J3eq,4 = 4.5 Hz, H-3eq-b), 2.16, 2.16,
2.07, 1.96, 1.78, 1.43 (6s, 18H, 6Ac), 1.73 (t, 1H, Jgem = 12.6 Hz,
H-3ax-b), 1.13 and 0.84 (2t, 6H, 2CH2CH3); MALDI-TOFMS: calcd
for [C46H58NO23P+K]+: m/z 1062.27. Found: m/z 1062.18.
3.10. [Methyl 5-acetamido-8-O-(5-acetamido-4,7,8,9-tetra-O-
acetyl-3,5-dideoxy-
ono-10,9-lactone)-4,7-di-O-acetyl-3,5-dideoxy-
-galacto-2-nonulopyranosylonate]-(2?3)-2,4,6-tri-O-
benzoyl- -galactopyranosyl diethylphosphite (32)
D-glycero-a-D-galacto-2-nonulopyranosyl-
D-glycero-
a-D
D
To a solution of compound 30 (80 mg, 60
(1.5 mL) were added N,N-diisopropylethylamine (32
and ClP(OEt)2 (22 L, 151 mol), and the reaction mixture was
lmol) in MeCN
l
L, 181 mol)
l
l
l
3.8. Phenyl 6-O-acetyl-2-O-benzoyl-3,4-di-O-benzyl-1-thio-b-
galactopyranoside (26)
D
-
stirred at 0 °C to room temperature for 1 h and monitored by TLC
(15:1 CHCl3–MeOH). After the completion of the reaction, the sol-
vent was evaporated. The residue was purified by column chroma-
tography on silica gel (40:1 CHCl3–MeOH) to give 32 (76 mg, 87%,
The suspension of compound 25 (560 mg, 1.00 mmol) and AW-
300 molecular sieves (1.9 g) in dry CH2Cl2 (10 mL) was stirred at
room temperature for 2 h. After the suspension was cooled to
ꢀ78 °C, Et3SiH (0.48 mL, 3.02 mmol) and PhBCl2 (0.45 mL,
3.43 mmol) were added, and the mixture was stirred at ꢀ78 °C
for 1.5 h. The progress of the reaction was monitored by TLC (1:4
EtOAc–toluene). Et3N and MeOH were added to quench the reac-
tion, and the mixture was filtered through Celite. The combined fil-
trate and washings were diluted with CHCl3, and the organic layer
was washed with satd NaHCO3 and brine, dried over Na2SO4, and
concentrated. The residue was dissolved in pyridine (10 mL),
Ac2O (0.48 mL, 5.04 mmol) and a catalytic amount of DMAP were
added, and the reaction mixture was stirred at room temperature
for 14 h. Then MeOH was added at 0 °C, the reaction mixture was
co-evaporated with toluene, and diluted with CHCl3. The organic
layer was washed with 2 M HCl, H2O, satd NaHCO3, and brine,
dried over Na2SO4, and concentrated. The residue was purified by
column chromatography on silica gel (1:20 EtOAc–toluene) to give
a
:b = 5.5:1); 1H NMR (600 MHz, CDCl3):
a-isomer; d 8.07, 8.05 and
8.00 (3d, 6H, Ph), 7.60–7.39 (m, 9H, Ph), 6.03 (dd, 1H, J1,2 = 4.1 Hz,
H-2a), 5.87 (d, 1H, J3,4 = 3.4 Hz, H-4a), 5.58 (td, 1H, J3eq,4 = 5.5 Hz,
H-4c), 5.56 (d, 1H, J1,2 = 4.1 Hz, H-1a), 5.56 (d, 1H, J5,NH = 10.3 Hz,
NH-b), 5.48 (dd, 1H, J3,4 = 3.4 Hz, H-3a), 5.44 (d, 1H, J5,NH = 10.3 Hz,
NH-c), 5.35 (dd, 1H, J6,7 = 2.1 Hz, H-7c), 5.26 (td, 1H, J3eq,4 = 5.5 Hz,
H-4b), 5.19 (m, 1H, H-8c), 5.01 (dd, 1H, J6,7 = 1.3 Hz, H-7b), 4.72 (m,
1H, H-8b), 4.72 (dd, 1H, H-6a), 4.66 (t, 1H, H-5a), 4.45–4.38 (m, 2H,
H-60a, 9b), 4.29 (dd, 1H, Jgem = 13.0 Hz, H-9c), 4.23 (q, 1H,
J5,6 = J5,NH = 10.3 Hz, H-5b), 4.13 (q, 1H, J5,6 = J5,NH = 10.3 Hz, H-5c),
4.06 (dd, 1H, H-90b), 4.02 (dd, 1H, Jgem = 13.0 Hz, H-90c), 3.94 (dd,
1H, J5,6 = 10.3 Hz, J6,7 = 1.3 Hz, H-6b), 3.92 (dd, 1H, J5,6 = 10.3 Hz,
J6,7 = 2.1 Hz, H-6c), 3.84–3.79 (m, 2H, 2CH2CH3), 3.78–3.69 (m,
2H, 2CH2CH3), 3.20 (s, 3H, COOMe), 2.50 (dd, 1H, Jgem = 13.0 Hz,
J3eq,4 = 5.5 Hz, H-3eq-c), 2.22 (dd, 1H, Jgem = 13.0 Hz, J3eq,4 = 5.5 Hz,
H-3eq-b), 2.16 (t, 1H, Jgem = 13.0 Hz, H-3ax-b), 2.12, 2.11, 2.10,
2.05, 2.05, 1.94, 1.89 and 1.88 (8s, 24H, 8Ac), 1.62 (t, 1H,
Jgem = 13.0 Hz, H-3ax-c), 1.08 and 1.01 (2t, 6H, 2CH2CH3); MALDI-
TOFMS: calcd for [C66H79N2O32P+Na]+: m/z 1465.42. Found: m/z
1465.54.
26 (512 mg, 85%); [a]
+32.0 (c 0.35, CHCl3); 1H NMR (600 MHz,
D
CDCl3): d 8.03–7.14 (m, 20H, 4Ph), 5.70 (t, 1H, J1,2 = J2,3 = 9.6 Hz,
H-2), 5.00 and 4.64 (2d, 2H, Jgem = 11.7 Hz, OCH2), 4.75 (d, 1H,
H-1), 4.66 and 4.54 (2d, 2H, Jgem = 12.3 Hz, OCH2), 4.29 (dd, 1H,
Jgem = 10.9 Hz, H-6), 4.13 (dd, 1H, Jgem = 10.9 Hz, H-60), 3.91 (d, 1H,
H-4), 3.71 (dd, 1H, J2,3 = 9.6 Hz, H-3), 3.68 (t, 1H, H-5), 2.00
(s, 3H, Ac); 13C NMR (150 MHz, CDCl3): d 170.5, 165.2, 137.9,
137.3, 133.4, 133.0, 132.1, 129.9, 129.8, 128.6, 128.3, 128.3,
128.2, 127.8, 127.7, 127.7, 127.5, 86.7, 81.2, 76.2, 74.1, 72.3, 72.2,
70.2, 63.4, 20.7; MALDI-TOFMS: calcd for [C35H34O7S+Na]+: m/z
621.19. Found: m/z 621.19.
3.11. 2-(Trimethylsilyl)ethyl 6-O-acetyl-2-O-benzoyl-3,4-di-
O-benzyl-b-
4-O-benzyl-2-deoxy-b-
acetamido-4,7,8,9-tetra-O-acetyl-3,5-dideoxy-
galacto-2-nonulopyranosylonate-(2?3)}-2,6-di-O-benzyl-b-
galactopyranosyl-(1?4)-2,3,6-tri-O-benzyl-b- -glucopyranoside
(33)
D
-galactopyranosyl-(1?3)-2-acetamido-6-O-acetyl-
-galactopyranosyl-(1?4)-{methyl 5-
-glycero-
D
D
a-D-
D-
D
3.9. Methyl 5-acetamido-4,7,8,9-tetra-O-acetyl-3,5-dideoxy-
A suspension of compound 26 (42 mg, 69
(59 mg, 34 mol), and 4 Å molecular sieves (160 mg) in dry CH2Cl2
(2.0 mL) was stirred at room temperature for 1 h. NIS (39 mg,
173 mol) was added to the mixture. The mixture was then cooled
to 0 °C, and TfOH (1.5 L, 17 mol) was added. The mixture was
stirred at 0 °C for 2 h, with monitoring by TLC (20:1 CHCl3–MeOH).
Et3N was added to quench the reaction. The mixture was filtered
through Celite. The combined filtrate and washings were diluted
lmol), compound 24
D-glycero-a-D-galacto-2-nonulopyranosylonate-(2?3)-4-O-
l
acetyl-2,6-di-O-benzoyl-D-galactopyranosyl diethylphosphite (29)
l
To a solution of compound 27 (120 mg, 132
(2.5 mL) were added N,N-diisopropylethylamine (69
and ClP(OEt)2 (39 L, 266 mol), and the reaction mixture was
stirred at 0 °C to room temperature for 1 h and monitored by TLC
lmol) in MeCN
l
l
l
L, 398 mol)
l
l
l

T. Komori et al. / Carbohydrate Research 344 (2009) 1453–1463
1461
with CHCl3, and the organic layer was washed with satd NaHCO3,
satd Na2S2O3, and brine, dried over Na2SO4, and concentrated.
The residue was purified by column chromatography on silica gel
H-3e), 4.77 (dt, 1H, H-4f), 4.67 and 4.52 (2d, 2H, Jgem = 10.3 Hz,
OCH2), 4.67 (d, 1H, J1,2 = 10.3 Hz, H-1d), 4.46 (dd, 1H, Jgem = 11.7 Hz,
H-6e), 4.43 (d, 1H, J1,2 = 7.5 Hz, H-1b), 4.41 (q, 2H, OCH2), 4.34 (d, 1H,
J1,2 = 7.5 Hz, H-1a), 4.33 (dd, 1H, Jgem = 11.7 Hz, H-60e), 4.29 (dd, 1H,
H-9f), 4.26 (d, 1H, OCH2), 4.19 (t, 1H, H-5e), 4.16–4.12 (m, 2H, H-3d,
6d), 4.08–3.85 (m, 13H, H-3b, 2d, 60d, 5c, 6c, 9c, 90c, 90f, OCH2,
COOMe, CH2CH2SiMe3), 3.80 (t, 1H, H-5d), 3.76–3.67 (m, 8H, H-4a,
4b, 4d, 5f, 6f, COOMe), 3.63–3.56 (m, 3H, H-6a, 60a, CH2CH2SiMe3),
3.51 (dd, 1H, Jgem = 10.9 Hz, H-6b), 3.45 (t, 1H, J2,3 = 8.9 Hz, H-3a),
3.43 (t, 1H, H-5b), 3.39 (m, 1H, H-5a), 3.31 (t, 1H, J1,2 = 7.5 Hz, H-
2b), 3.23 (dd, 1H, Jgem = 10.9 Hz, H-60b), 3.07 (t, 1H, J1,2 = 7.5 Hz,
J2,3 = 8.9 Hz, H-2a), 2.43 (dd, 1H, J3eq,4 = 4.8 Hz, H-3eq-c), 2.37 (dd,
1H, Jgem = 12.3 Hz, H-3eq-f), 2.15, 2.07, 2.07, 2.04, 2.00, 1.93, 1.92,
1.84, 1.84, 1.80, 1.76, 1.73 and 1.67 (13s, 39H, 13Ac), 2.07 (t, 1H,
H-3ax-c), 1.49 (t, 1H, Jgem = 12.3 Hz, H-3ax-f), 0.96 (m, 2H,
CH2SiMe3), 0.00 (s, 9H, CH2SiMe3); 13C NMR (150 MHz, CD3CN): d
171.4, 171.3, 171.2, 171.1, 171.0, 170.8, 170.7, 170.7, 170.6, 170.5,
170.2, 169.5, 168.9, 166.6, 165.7, 140.2, 140.1, 140.0, 139.9, 139.6,
139.6, 134.3, 134.1, 131.0, 130.8, 130.7, 130.4, 130.3, 129.7, 129.5,
129.5, 129.2, 129.2, 129.1, 129.1, 129.0, 129.0, 129.0, 128.9, 128.7,
128.5, 128.5, 128.3, 128.3, 128.3, 128.2, 128.1, 128.0, 103.7, 103.5,
103.4, 102.8, 100.4, 98.4, 83.3, 82.5, 81.7, 79.9, 78.7, 77.0, 76.9,
76.4, 76.2, 75.7, 75.4, 75.3, 75.3, 74.3, 73.6, 73.5, 72.7, 72.5, 72.4,
72.0, 71.6, 71.5, 70.6, 70.5, 70.2, 69.4, 69.1, 68.9, 68.8, 67.8, 67.6,
67.3, 64.5, 63.2, 62.9, 62.3, 53.8, 53.7, 52.4, 49.3, 49.1, 38.0, 35.8,
30.3, 23.3, 23.1, 23.0, 21.6, 21.4, 21.2, 21.1, 21.0, 20.9, 20.9, 20.9,
20.9, 20.8, 18.9, 1.9, ꢀ1.3; MALDI-TOFMS: calcd for [C131H159N3O49-
Si+Na]+: m/z 2608.97. Found: m/z 2608.31.
(30:30:1 EtOAc–toluene–MeOH) to give 33 (57 mg, 75%); [a]
D
ꢀ5.5 (c 1.0, CHCl3); Ratio of rotamer A:B: 1.80:1 (CDCl3), 9.62:1
(CD3CN), 10.4:1 (THF-d8); rotamer A: 1H NMR (600 MHz, THF-
d8): d 8.00–6.81 (m, 46H, NH-d, 9Ph), 6.77 (d, 1H, NH-c), 5.69
(t, 1H, J1,2 = 8.2 Hz, H-2e), 5.62 (m, 1H, H-8c), 5.29 (dd, 1H, H-7c),
5.11 (d, 1H, J1,2 = 8.2 Hz, H-1d), 5.06 and 4.76 (2d, 2H,
Jgem = 11.7 Hz, OCH2), 5.04 (d, 1H, J1,2 = 10.9 Hz, H-1a), 5.01 and
4.61 (2d, 2H, Jgem = 11.6 Hz, OCH2), 4.96 and 4.62 (2d, 2H,
Jgem = 12.3 Hz, OCH2), 4.86 and 4.69 (2d, 2H, Jgem = 11.6 Hz, OCH2),
4.85 and 4.59 (2d, 2H, Jgem = 10.3 Hz, OCH2), 4.82 (d, 1H,
J1,2 = 8.2 Hz, H-1e), 4.75 (td, 1H, J3eq,4 = 4.8 Hz, H-4c), 4.70 (d, 1H,
J1,2 = 7.5 Hz, H-1b), 4.67 and 4.54 (2d, 2H, Jgem = 11.7 Hz, OCH2),
4.43 (d, 1H, OCH2), 4.32–4.25 (m, 5H, H-3b, 3d, 6e, 2OCH2), 4.17–
4.13 (m, 2H, H-9c, 60e), 4.11–4.03 (m, 6H, H-4b, 5c, 6d, 60d, 4e,
OCH2), 3.98–3.92 (m, 2H, H-90c, CH2CH2SiMe3), 3.84–3.80 (m, 2H,
H-3e, 6c), 3.78–3.75 (m, 5H, H-6a, 5e, COOMe), 3.67 (t, 1H, H-
5d), 3.60–3.54 (m, 5H, H-4a, 60a, 6b, 4d, CH2CH2SiMe3), 3.54
(t, 1H, J1,2 = 7.5 Hz, H-2b), 3.47 (t, 1H, H-5b), 3.45 (t, 1H, H-3a),
3.39 (m, 1H, H-5a), 3.26 (dd, 1H, H-60b), 3.22–3.17 (m, 2H, H-2a,
2d), 2.93 (dd, 1H, Jgem = 13.7 Hz, J3eq,4 = 4.8 Hz, H-3eq-c), 2.01,
1.95, 1.91, 1.82, 1.74, 1.68, 1.65 and 1.44 (8s, 24H, 8Ac), 1.81 (t,
1H, Jgem = 13.7 Hz, H-3ax-c), 0.96 (m, 2H, CH2SiMe3), 0.00 (s, 9H,
CH2SiMe3); 13C NMR (150 MHz, THF-d8): d 170.4, 170.3, 170.3,
170.1, 170.1, 169.8, 169.6, 169.4, 165.0, 140.8, 140.4, 140.3,
140.2, 139.9, 139.6, 139.0, 133.4, 131.6, 130.5, 129.5, 129.2,
128.9, 128.7, 128.6, 128.6, 128.5, 128.5, 128.4, 128.4, 128.2,
128.1, 128.0, 128.0, 127.9, 127.9, 127.7, 127.7, 127.6, 127.5,
127.4, 127.3, 127.3, 103.6, 103.3, 100.1, 99.0, 83.7, 83.0, 81.4,
80.4, 78.6, 77.9, 77.0, 76.5, 76.0, 75.6, 75.1, 74.8, 74.8, 74.2, 74.2,
73.8, 73.3, 73.2, 73.1, 72.9, 72.9, 72.6, 72.2, 70.2, 69.8, 69.0, 67.7,
67.7, 67.6, 67.4, 63.9, 63.5, 62.8, 55.6, 52.8, 49.5, 38.5, 30.5, 25.6,
25.5, 25.3, 23.7, 22.6, 21.1, 20.6, 20.5, 20.4, 20.4, 20.3, 18.9, ꢀ1.2;
MALDI-TOFMS: calcd for [C118H140N2O36Si+Na]+: m/z 2211.88.
Found: m/z 2211.77.
3.13. 2-(Trimethylsilyl)ethyl [methyl 5-acetamido-8-O-(5-acet-
amido-4,7,8,9-tetra-O-acetyl-3,5-dideoxy-
2-nonulopyranosylono-10,9-lactone)-4,7-di-O-acetyl-3,5-dide-
oxy- -glycero- -galacto-2-nonulopyranosylonate]-(2?3)-
2,4,6-tri-O-benzoyl-b- -galactopyranosyl-(1?3)-2-acetamido-
6-O-acetyl-4-O-benzyl-2-deoxy-b- -galactopyranosyl-(1?4)-
{methyl 5-acetamido-4,7,8,9-tetra-O-acetyl-3,5-dideoxy- -gly-
cero- -galacto-2-nonulopyranosylonate-(2?3)}-2,6-di-O-
benzyl-b- -galactopyranosyl-(1?4)-2,3,6-tri-O-benzyl-b-
D-glycero-a-D-galacto-
D
a-D
D
D
D
a
-D
D
D-
3.12. 2-(Trimethylsilyl)ethyl (methyl 5-acetamido-4,7,8,9-tetra-
glucopyranoside (35)
O-acetyl-3,5-dideoxy-
sylonate)-(2?3)-4-O-acetyl-2,6-di-O-benzoyl-b-
anosyl-(1?3)-2-acetamido-6-O-acetyl-4-O-benzyl-2-deoxy-b-
galactopyranosyl-(1?4)-{methyl 5-acetamido-4,7,8,9-tetra-O-
acetyl-3,5-dideoxy- -glycero- -galacto-2-nonulopyrano-
sylonate-(2?3)}-2,6-di-O-benzyl-b- -galactopyranosyl-(1?4)-
2,3,6-tri-O-benzyl-b- -glucopyranoside (34)
D
-glycero-
a
-
D
-galacto-2-nonulopyrano-
D-galactopyr-
A suspension of compound 32 (74 mg, 51 lmol), compound 24
D-
(44 mg, 25
CH2Cl2 (2.0 mL) was stirred at room temperature for 1 h. After the
suspension was cooled to 15 °C, TMSOTf (1.9 L, 10 mol) was
lmol), and AW-300 molecular sieves (155 mg) in dry
D
a-
D
l
l
D
added, and the reaction mixture was stirred at 15 °C for 5.5 h. The
progress of the reaction was monitored by TLC (5:5:1 EtOAc–tolu-
ene–MeOH). After quenching the reaction, the mixture was worked
up as described for compound 34. The resulting residue was chro-
matographed on silica gel (12:12:1?5:5:1 EtOAc–toluene–MeOH)
D
A suspension of compound 29 (48 mg, 46
(40 mg, 23
CH2Cl2 (2.0 mL) was stirred at room temperature for 1 h. The mix-
ture was cooled to 0 °C, TMSOTf (1.7 L, 9.2 mol) was added, and
l
mol), compound 24
lmol), and AW-300 molecular sieves (203 mg) in dry
to give 35 (52 mg, 68%); [
a
]D ꢀ17.5 (c 0.37, CHCl3); Ratio of rotamer
l
l
A:B: 2.18:1 (CDCl3), 11.0:1 (THF-d8), 12.4:1 (CD3CN); rotamer A: 1H
NMR (600 MHz, THF-d8): d 8.07–6.73 (m, 47H, NH-d, NH-g, 9Ph),
6.99 (d, 1H, NH-f), 6.79 (d, 1H, NH-c), 5.88 (d, 1H, H-4e), 5.65 (t,
1H, J1,2 = 7.5 Hz, H-2e), 5.63 (m, 1H, H-8c), 5.52 (td, 1H,
J3eq,4 = 5.5 Hz, H-4g), 5.35 (dd, 1H, H-7g), 5.30 (dd, 1H, H-7c), 5.26
(d, 1H, J1,2 = 10.9 Hz, H-1d), 5.22 (dd, 1H, H-7f), 5.17 (d, 1H,
J1,2 = 7.5 Hz, H-1e), 5.14 (d, 1H, J1,2 = 8.2 Hz, H-1a), 5.08 (m, 1H, H-
8g), 5.04 (td, 1H, H-4f), 4.98 and 4.62 (2d, 2H, Jgem = 12.3 Hz,
OCH2), 4.88–4.83 (m, 3H, 3OCH2), 4.78 (td, 1H, J3eq,4 = 4.1 Hz,
H-4c), 4.74–4.71 (m, 5H, H-1b, 3e, 8f, 2OCH2), 4.69 (d, 1H, OCH2),
4.61 (d, 1H, OCH2), 4.56 (dd, 1H, Jgem = 11.7 Hz, H-6e), 4.44 (dd, 1H,
Jgem = 11.7 Hz, H-60e), 4.44 (d, 1H, OCH2), 4.36 (t, 1H, H-5e), 4.35–
4.21 (m, 6H, H-3b, 3d, 9f, 9g, 2OCH2), 4.18–4.02 (m, 6H, H-5c, 9c,
6d, 60d, 5f, 5g), 4.01–3.94 (m, 4H, H-4b, 90c, 90g, CH2CH2SiMe3),
3.85–3.75 (m, 8H, H-6a, 6c, 6f, 90f, 6g, COOMe), 3.72 (t, 1H, H-5d),
3.60–3.55 (m, 5H, H-4a, 60a, 6b, 4d, CH2CH2SiMe3), 3.54 (t, 1H,
the reaction mixture was stirred at 0 °C for 2 h with monitoring by
TLC (40:1 CHCl3–MeOH). Et3N was added to quench the reaction.
The mixture was filtered through Celite. The combined filtrate and
washings were diluted with CHCl3 and the organic layer was washed
with satd NaHCO3, and brine, dried over Na2SO4, and concentrated.
The residue was purified by column chromatography on silica gel
(50:1?35:1 CHCl3–MeOH) to give 34 (36 mg, 60%); [
a
]
D
ꢀ5.9 (c
0.84, CHCl3); Ratio of rotamer A:B: 2.83:1 (CDCl3), 8.60:1 (THF-d8),
14.7:1 (CD3CN); rotamer A: 1H NMR (600 MHz, CD3CN): d 8.08–
6.77 (m, 40H, 8Ph), 6.10 (d, 1H, NH-c), 6.08 (d, 1H, NH-d), 5.97 (d,
1H, NH-f), 5.47 (m, 1H, H-8f), 5.35–5.31 (m, 2H, H-2e, 4e), 5.21
(dd, 1H, H-7f), 5.20 (dd, 1H, H-7c), 5.18 (m, 1H, H-8c), 5.01 (dt, 1H,
J3eq,4 = 4.8 Hz, H-4c), 5.00 (d, 1H, J1,2 = 8.2 Hz, H-1e), 4.97 and 4.69
(2d, 2H, Jgem = 11.0 Hz, OCH2), 4.85 and 4.51 (2d, 2H, Jgem = 9.6 Hz,
OCH2), 4.81 and 4.73 (2d, 2H, Jgem = 11.0 Hz, OCH2), 4.81 (dd, 1H,

1462
T. Komori et al. / Carbohydrate Research 344 (2009) 1453–1463
H-2b), 3.48 (t, 1H, H-5b), 3.46 (t, 1H, H-3a), 3.40 (m, 1H, H-5a), 3.26
(dd, 1H, H-60b), 3.24–3.20 (m, 2H, H-2a, 2d), 3.14 (s, 3H, COOMe),
2.96 (dd, 1H, J3eq,4 = 4.1 Hz, H-3eq-c), 2.56 (dd, 1H, Jgem = 13.0 Hz,
J3eq,4 = 5.5 Hz, H-3eq-g), 2.12–1.68 (m, 3H, H-3ax-c, 3eq-f, 3ax-f),
2.03, 2.02, 1.98, 1.95, 1.94, 1.85, 1.80, 1.79, 1.69, 1.68, 1.68 and
1.41 (12s, 45H, 15Ac), 1.46 (t, 1H, Jgem = 13.0 Hz, H-3ax-g), 0.96 (m,
2H, CH2CH2SiMe3), 0.00 (s, 9H, CH2SiMe3); 13C NMR (150 MHz,
CD3CN): d 171.3, 171.2, 171.2, 170.9, 170.8, 170.7, 170.6, 170.6,
170.5, 170.4, 170.2, 170.1, 169.6, 168.5, 166.7, 166.5, 165.2, 165.1,
140.2, 140.1, 139.9, 139.6, 134.3, 134.3, 130.7, 130.6, 130.6, 130.5,
130.2, 129.7, 129.6, 129.5, 129.4, 129.2, 129.1, 129.1, 129.0, 128.9,
128.7, 128.6, 128.5, 128.4, 128.3, 128.3, 128.2, 128.1, 128.0, 117.0,
103.8, 103.5, 103.2, 102.8, 100.5, 98.6, 83.3, 82.5, 82.3, 79.9, 78.8,
77.4, 76.8, 76.4, 76.3, 75.8, 75.7, 75.4, 75.3, 74.3, 73.6, 73.5, 72.7,
72.7, 72.4, 72.4, 71.8, 70.9, 70.6, 70.4, 69.7, 69.2, 69.0, 68.7, 67.6,
67.3, 64.5, 63.9, 62.6, 62.3, 53.8, 53.2, 52.5, 49.4, 49.3, 48.4, 39.3,
36.0, 35.8, 30.3, 23.1, 23.1 23.0, 23.0, 21.4, 21.1, 21.1, 21.0, 21.0,
20.9, 20.9, 20.9, 20.8, 18.9, 2.7, 2.5, 1.8, ꢀ1.3; MALDI-TOFMS: calcd
for [C151H180N4O58Si+Na]+: m/z 3028.09. Found: m/z 3028.78.
room temperature for 2 days and at 50 °C for another 3 days. Then
H2O was added, and the mixture was stirred at 40 °C for 1 day
(TLC; 2:1:1 n-BuOH–MeOH–5% aq CaCl2). The mixture was cooled
to room temperature and neutralized with IR-120 (H+) resin and
filtered through cotton, and the combined filtrate and washings
were concentrated. The residue was purified by gel-filtration col-
umn chromatography on Sephadex LH-20 (1:1 MeOH–H2O) to give
2 (10 mg, 81%); [
a]
+6.9 (c 1.0, 1:1 MeOH–H2O); 1H NMR
D
(500 MHz, 1:1 CD3OD–D2O): d 2.73 (dd, 1H, H-3eqNeu), 2.67 (dd,
1H, H-3eqNeu), 2.01, 2.00 and 1.97 (3s, 9H, 3NAc), 1.86 (t, 1H,
H-3axNeu), 1.77 (t, 1H, H-3axNeu), 0.99 (m, 2H, CH2CH2SiMe3), 0.00
(s, 9H, CH2SiMe3); 13C NMR (125 MHz, 1:1 CD3OD–D2O): d 176.0,
175.8, 175.3, 175.0, 174.9, 105.7, 103.9, 103.7, 102.8, 102.7,
100.8, 81.9, 80.0, 78.2, 76.7, 75.8, 75.8, 75.7, 75.6, 75.4, 75.2,
74.3, 74.0, 74.0, 73.2, 72.8, 71.0, 70.3, 69.5, 69.4, 68.9, 68.5, 64.2,
63.7, 62.3, 62.1, 61.6, 61.2, 53.1, 53.0, 52.1, 41.0, 38.3, 23.6, 22.8,
18.7, ꢀ1.4; MALDI-TOFMS: calcd for [C53H87N3O37Si+3Na]+: m/z
1456.46. Found: m/z 1456.63.
3.16. 2-(Trimethylsilyl)ethyl (5-acetamido-3,5-dideoxy-
cero- -galacto-2-nonulopyranosylonic acid)-(2?8)-(5-acet-
amido-3,5-dideoxy- -glycero- -galacto-2-nonulopyranosy-
lonic acid)-(2?3)-b- -galactopyranosyl-(1?3)-2-acetamido-2-
deoxy-b- -galactopyranosyl-(1?4)-{5-acetamido-3,5-dideoxy-
-glycero- -galacto-2-nonulopyranosylonic acid-(2?3)}-b-
galactopyranosyl-(1?4)-b- -glucopyranoside (3)
D-gly-
3.14. 2-(Trimethylsilyl)ethyl b-
acetamido-2-deoxy-b- -galactopyranosyl-(1?4)-{5-acetamido-
3,5-dideoxy- -glycero- -galacto-2-nonulopyranosylonic acid-
(2?3)}-b- -galactopyranosyl-(1?4)-b- -glucopyranoside (1)
D
-galactopyranosyl-(1?3)-2-
a-D
D
D
a-D
D
a
-
D
D
D
D
D
D
a-
D
D-
To a solution of compound 33 (57 mg, 26
lmol) in 1:1 EtOH–
D
THF (4.0 mL) was added 20% Pd(OH)2-on-charcoal (53 mg). The
suspension was stirred at 40 °C under an H2 atmosphere for 19 h.
The progress of the reaction was monitored by TLC (5:1 CHCl3–
MeOH). The reaction mixture was filtered through Celite, and the
combined filtrate and washings were concentrated. The residue
was dissolved in MeOH, a catalytic amount of NaOMe (28% MeOH
solution) was added, and the resulting mixture was stirred at room
temperature for 3 days and at 40 °C for another 2 days. H2O was
then added to the mixture, and the mixture was stirred at 40 °C
for 1 day (TLC; 2:1:1 n-BuOH–MeOH–5% aq CaCl2). The mixture
was cooled to room temperature and neutralized with IR-120
(H+) resin, filtered through cotton, and the combined filtrate and
washings were concentrated. The residue was purified by gel-fil-
tration column chromatography on Sephadex LH-20 (1:1 MeOH–
To a solution of compound 35 (96 mg, 31 lmol) in 1:1 EtOH–
THF (4 mL) was added 20% Pd(OH)2-on-charcoal (95 mg). The sus-
pension was stirred at 40 °C under an H2 atmosphere for 13 h, with
monitoring of the reaction by TLC (10:1 CHCl3–MeOH). The reac-
tion mixture was filtered through Celite and the combined filtrate
and washings were concentrated. The residue was dissolved in
MeOH, and a catalytic amount of NaOMe (28% MeOH solution)
was added. The resulting mixture was stirred at room temperature
for 2.5 days and at 50 °C for another 3 days. Then H2O was added,
and the mixture was stirred at 40 °C for 1 day, with monitoring of
the reaction by TLC (2:1:1 n-BuOH–MeOH5% aq CaCl2). The mix-
ture was cooled to room temperature, neutralized with IR-120
(H+) resin, and filtered through cotton, and the combined filtrate
and washings were concentrated. The residue was purified by
gel-filtration column chromatography on Sephadex LH-20 (1:1
H2O) to give 1 (25 mg, 87%); [a] +9.7 (c 0.41, 1:1 MeOH–H2O);
D
1H NMR (500 MHz, 1:1 CD3OD–D2O): d 2.65 (dd, 1H, Jgem = 12.5 Hz,
H-3eq-c), 2.01 and 1.97 (2s, 6H, 2NAc), 1.88 (t, 1H, Jgem = 12.5 Hz,
H-3ax-c), 0.99 (m, 2H, CH2SiMe3), 0.00 (s, 9H, CH2SiMe3); 13C
NMR (125 MHz, 1:1 CD3OD–D2O): d 176.0, 175.4, 175.0, 105.9,
103.9, 103.6, 102.9, 81.8, 80.1, 78.5, 76.0, 75.8, 75.8, 75.6, 75.4,
75.2, 74.4, 74.0, 73.8, 73.2, 71.9, 71.0, 69.8, 69.5, 69.4, 69.1, 68.9,
64.2, 62.3, 62.0, 61.6, 61.2, 53.0, 52.2, 38.0, 23.6, 22.8, 18.7, ꢀ1.4;
MALDI-TOFMS: calcd for [C42H74N2O29Si+Na]+: m/z 1121.40.
Found: m/z 1121.59.
MeOH–H2O) to give 3 (49 mg, 92%); [
a
]
ꢀ4.7 (c 1.1, 1:1 MeOH–
D
H2O); 1H NMR (500 MHz, 1:1 CD3OD–D2O): d 2.97 (br d, 1H, H-3eq-
Neu), 2.66 (br d, 2H, 2H-3eqNeu), 2.01, 2.00 and 2.00 (3s, 12H, 4NAc),
1.89 (t, 1H, H-3axNeu), 1.68 (t, 2H, 2H-3axNeu), 0.99 (m, 2H,
CH2SiMe3), 0.00 (s, 9H, CH2SiMe3); 13C NMR (125 MHz, 1:1
CD3OD–D2O): d 176.3, 176.1, 175.6, 175.5, 175.4, 174.4, 174.3,
105.4, 103.9, 103.5, 102.9, 101.8, 101.0, 81.6, 80.0, 78.8, 78.2,
75.9, 75.8, 75.6, 75.4, 75.2, 75.1, 74.7, 74.4, 74.3, 74.0, 73.2, 72.7,
70.9, 70.5, 69.6, 69.5, 69.4, 69.0, 69.0, 68.9, 68.8, 68.6, 67.9, 64.3,
63.9, 62.7, 62.3, 62.1, 61.5, 61.2, 54.0, 53.4, 53.2, 52.4, 42.5, 41.5,
37.9, 23.8, 23.0, 22.9, 22.8, 18.7, ꢀ1.4; MALDI-TOFMS: calcd for
[C64H102N4Na4O45Si+4Na]+: m/z 1769.54. Found: m/z 1769.59.
3.15. 2-(Trimethylsilyl)ethyl (5-acetamido-3,5-dideoxy-
cero- -galacto-2-nonulopyranosylonic acid)-(2?3)-b-
topyranosyl-(1?3)-2-acetamido-2-deoxy-b-
(1?4)-{5-acetamido-3,5-dideoxy- -glycero-
-galactopyranosyl-(1?4)-b-
D
-gly-
a
-
D
D-galac-
D
-galactopyranosyl-
a-D-galacto-2-nonu-
D
lopyranosylonic acid-(2?3)}-b-
D
D
-
Acknowledgments
glucopyranoside (2)
This work was financially supported by MEXT of Japan (WPI pro-
gram and Grant-in-Aid for Scientific Research to M.K., No.
1701007). We thank Ms. Kiyoko Ito for technical assistance.
To a solution of compound 34 (23 mg, 8.8 lmol) in 1:1 EtOH–
THF (2.0 mL) was added 20% Pd(OH)2-on-charcoal (20 mg). The
suspension was stirred at 40 °C under an H2 atmosphere for 15 h.
The progress of the reaction was monitored by TLC (10:1 CHCl3–
MeOH). The reaction mixture was filtered through Celite, and the
combined filtrate and washings were concentrated. The residue
was dissolved in MeOH, and a catalytic amount of NaOMe (28%
MeOH solution) was added. The resulting mixture was stirred at
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