Total Synthesis of a Hyperbranched N-Linked Hexasaccharide Attached to ATCV-1 Major Capsid Protein without Precedent

Article abstract of DOI:10.1002/cjoc.201800533

The N-glycans attached to some chloroviruses comprise a hyperbranched core structure without precedent. We are interested in the chemical synthesis of the hexasaccharide attached to ATCV-1 (Acanthocystis turfacea Chlorella virus 1) for its distinct structure. After exploring four routes, the target hexasaccharide 2 was successfully synthesized for the first time in overall 10% yield over 8 steps from thioglycoside building blocks. This synthetic protocol is characterized by the three-component one-pot glycosylation and the regioselective glycosylation reactions. The disclosed synthetic approach to this new type of N-glycans will facilitate the in-depth understanding of their biological functions.

Full text of DOI:10.1002/cjoc.201800533

Total Synthesis of a Hyperbranched N-Linked Hexasaccharide Attached
to ATCV-1 Major Capsid Protein without Precedent
a
a
a,b
,a
Yong-Shi Wang, Yong Wu, De-Cai Xiong, and Xin-Shan Ye*
ABSTRACT The N-glycans attached to some chloroviruses comprise a hyperbranched core structure without precedent. We are interested in the
chemical synthesis of the hexasaccharide attached to ATCV-1 (Acanthocystis turfacea Chlorella virus 1) for its distinct structure. After exploring four
routes, the target hexasaccharide 2 was successfully synthesized for the first time in overall 10% yield over 8 steps from thioglycoside building blocks.
This synthetic protocol is characterized by the three-component one-pot glycosylation and the regioselective glycosylation reactions. The disclosed
synthetic approach to this new type of N-glycans will facilitate the in-depth understanding of their biological functions.
KEYWORDS N-glycan; ATCV-1; one-pot; glycosylation; total synthesis
Introduction
structures from PBCV-1 (Paramecium bursaria chlorella virus 1) and
ATCV-1 (Acanthocystis turfacea Chlorella virus 1).
N-Glycosylation is a critical modification of proteins existing
[
1]
widely in three domains of life and some viruses. N-Glycans
exhibit vital roles in numerous biological processes, including
protein folding, cell signal mediation, intracellular trafficking
[
2]
regulation and immune balance. Although N-glycans are of great
complexity and variety, they all comprise a common core
pentasaccharide structure Man
3 2
GlcNAc linked to an Asn residue
which is located in the typical sequence N-X-T/S by
a
[3]
β-glucosamine linkage. Recently, Van Etten and co-workers have
discovered that the N-glycans from a series of chloroviruses have
a new type of core structure that dose not resemble any reported
[
4]
structure (Scheme 1). This new conserved core motif is a
pentasaccharide attached to protein via β-glucose-Asn linkage. As
for the pentasaccharide, the glucose is linked to a proximal
β-xylose at O4 and a hyperbranced α-fucose at O3. The fucose
unit is fully substituted and has an α-galactose at O2 and a distal
β-xylose at O4. The hyperbranced fucose structure makes the new
core motif especially distinctive. Fucose residue is usually located
[6]
[
5]
at the terminal end of oligosaccharides (such as Globo H, KH-1,
[
7]
complex N-glycan ) or is comprised in fucoidan whose central
chain is the repeating (1→3)- and (1→4)-linked α-fucosyl
residue.
Scheme 2 Chemical structures of N-glycans from ATCV-1.
[8]
Among all the chloroviruses where the new type of N-glycans
have been found, ATCV-1 (Acanthocystis turfacea Chlorella virus 1)
stands out for it may alter cognition function. It was found that
ATCV-1 is associated with cognitive changes in humans acting as a
[
9]
part of human virome. It was reported that ATCV-1 can damage
[
10]
the hippocampus in experimentally infected mice. Considering
the new N-glycan structure motif and potential activities of
ATCV-1, we are interested in the chemical synthesis of the
hexasaccharide (Scheme 2) attached to the ATCV-1 major capsid
protein. Besides the common core motif, this hexasaccharide
possesses a 3-O-methylated L-rhamnose at the O3 position of
fucose unit, along with methyl groups that are nonstoichiometric
decorated at the O4 position of xylose units, thus leading to four
Results and Discussion
The target hexasaccharide
2 presents several tricky
α-glycosidic bonds such as α-fucosidic and α-galactosidic bonds.
The more challenging issue is how to construct the
hyperbranched fucose residue. The retrosynthetic analysis of
target compound 2 is shown in Scheme 3. The trisaccharides 3 or
[
4b]
similar N-glycan derivatives. Herein we report the synthesis of
core hexasaccharide 2 (Scheme 3) via the preactivation-based
[
11]
one-pot strategy using thioglycoside building blocks to simplify
1
0 were chosen, to which several monosaccharide building blocks
could be connected in a sequential manner. Both of the
trisaccharides and 10 could be assembled via
preactivation-based one-pot glycosylation protocol.
[12]
synthetic procedures.
The target compound 2 with a free
hydroxyl group at the reducing end could be further modified via
3
[
13]
aspartylation reported previously.
[11, 14]
In order
to facilitate the description of our synthetic strategy, each sugar
residue was assigned a roman numeral. There are several
synthetic strategies toward the target molecule, for example, II' +
Scheme 1 Structures of N-glycans. (a) Typical core motif of N-glycans. (b)
Typical N-glycan structures from mammals, plants and yeast. (c) The new
type core motif of N-glycan from chloroviruses. (d) New type N-glycan
a
State Key Laboratory of Natural and Biomimetic Drugs, School of
Pharmaceutical Sciences, Peking University, Xue Yuan Road No. 38, Beijing
100191 (China)
b
State Key Laboratory of Drug Research, Shanghai Institute of Materia
Medica, Chinese Academy of Sciences, Shanghai 200031 (China)
*E-mail: xinshan@bjmu.edu.cn
This article has been accepted for publication and undergone full peer review but has not
been through the copyediting, typesetting, pagination and proofreading process, which
may lead to differences between this version and the Version of Record. Please cite this
article as doi: 10.1002/cjoc.201800533
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II + I + II'' + III + I', I + II + II' + II'' + III + I', III + II + I + II' + II''+ I' and
III + II + I + II''+ II' + I', which stand for the coupled sequence of the
monosaccharide building blocks. To minimize the functional
group protection and deprotection manipulations, sugar units II'
and II'' would be added to the 3-/4-position of fucose moiety II via
a regioselective glycosylation, which would take advantage of the
reactivity difference between the two hydroxyl groups. All of the
monosaccharide building blocks were designed as thioglycosides
Scheme 4 The synthetic route of II' + II + I + II'' + III + I'. Reagents and
o
conditions: a) p-TolSCl, AgOTf, TTBP, CH
2
Cl
2
, -78 C to room temperature. b)
o
p-TolSCl, AgOTf, Et
2
O, -40 C to room temperature.
[
15]
due to their stable and easily-activated properties. Since the
formation of 1,2-cis galactosidic and 1,2-cis fucosidic linkages is
usually governed by the anomeric effect, we designed the
benzylated thioglycoside donor 5 and 2-O-p-methoxybenzylated
donor 8. In addition, the remote participation effect of acyl
substituents at C-4 was also found to be beneficial to the
[16]
formation of α-galactosides and α-fucosides.
Therefore, the
4-O-acetylated donor 6 and 3,4-di-O-benzoylated donor 11 were
also prepared.
Scheme 3 Retrosynthetic analysis of the target hexasaccharide 2.
We have to try the second route, that is, I + II + II' + II'' + III + I'
strategy (Scheme 5). In this route, the glycosylation of acceptor 9
with monosaccharide 16 promoted by p-TolSCl/AgOTf was
performed firstly, providing disaccharide 17 in 91% yield with
exclusive α-stereoselectivity. Removal of the two benzoyl groups
in 17 provided acceptor 18 in 92% yield. The glycosylation of 18
with donor 7 generated trisaccharide 3 in 63% yield. Compound 3
was then glycosylated with 3.0 equivalents of donor 4, providing
the desired tetrasaccharide 19 in 79% yield. After removal of the
PMB protecting group in 19 by DDQ oxidation, tetrasaccharide
acceptor 20 was obtained. Subsequently, the glycosylation of 20
with donor
5 was carried out. However, the desired
pentasaccharide 21 was not produced, the pentasaccharide 23
with the β-galactosidic linkage was the only isolated product (79%
yield) Instead. We also tried thiogalactoside donor 6 which may
have remote participation effect to influence the stereoselectivity
of glycosidic bond, but failed to provide the target
pentasaccharide 22 with the α-galactosidic linkage, and the
β-isomer 24 was gained (83% yield) once again. We speculated
that the steric hindrance of acceptor 20 might prevent donor 5/6
attacking from the α-side. To testify our speculation, we
performed the glycosylation reaction of disaccharide acceptor 25
with galactose donors (Table 1). The α-isomer of the coupled
product 26 was detected but still with low selectivity. The best
result of α/β ratio was only up to 2/1. In diethyl ether solvent
which facilitated α-glycoside formation, the percentage of
α-isomer even declined. Even for the disaccharide acceptor 25, it
seemed to possess steric hindrance at O2 position on the fucose
moiety. The steric hindrance of tetrasaccharide acceptor 20 did
restrict the formation of α-galactoside. Therefore, this synthetic
route was suspended.
The preparation of all monosaccharide building blocks was
shown in the supporting information. We started to carry out the
synthetic route of II' + II + I + II'' + III + I' (Scheme 4). To begin with,
the assembly of trisaccharide
3
commenced with the
non-reducing end block 7. The glycosylation of acceptor 8 with
donor 7 through p-TolSCl/AgOTf activation system afforded not
only the desired disaccharide 12 in 63% yield, but also
side-products disaccharide 13 in 11% yield and trisaccharide 14 in
Scheme 5 The synthetic route of I + II + II' + II'' + III + I'. Reagents and
o
conditions: a) p-TolSCl, AgOTf, TTBP, CH
CH
2
Cl
2
, -78 C to room temperature. b)
o
o
ONa/CH OH, 40 C, 10 h. c) p-TolSCl, AgOTf, TTBP, CH Cl , -40 C to
3 3 2 2
5
% yield. This unsatisfying regioselectivity may be probably
o
room temperature. d) DDQ, CH
2
2 2
Cl /H O (10:1), 0 C, 3 h.
attributed to the high reactivities of fucose and rhamnose units
and the electron-donating groups PMB and Bn. To improve the
regioselectivity, we tried to use different promoters and additives,
change reaction temperatures and solvents, but all failed at last
(
Table S1). Thus we continued to synthesize trisaccharide 3. The
coupling reaction of disaccharide 12 and galactose acceptor 9
obtained the desired compound 3 and its anomeric isomer 15 in a
total yield of 92% (α/β ratio 1.7/1). Because the trisaccharide
backbone 3 was assembled in low efficiency, we gave up this
synthetic route.
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Since we observed that the 4-OH is more reactive than the
-OH in acceptor 10, the glycosylation of trisaccharide 10 with
3
xylose donor 4 was carried out firstly (Scheme 7). The desired
tetrasaccharide 30 was successfully isolated in 61% yield and the
side-product pentasaccharide 31 was also collected in 15% yield.
The tetrasaccharide 30 was directly used as the acceptor which
was glycosylated with the rhamnose donor 7 to produce the
target pentasaccharide 21 in 78% yield. The selective opening of
the benzylidene ring in 21 was achieved by the treatment with
Table 1 Glycosylation of acceptor 25 with donor 5/6.
3
Et SiH/TfOH, affording acceptor 32 in 85% yield. Subsequently, the
glycosyl coupling reaction of pentasaccharide 32 and donor 4
generated hexasaccharide 33 in 47% yield. Finally, the
deprotection of all the Bz and Bn groups in 33 afforded the target
hexasaccharide 2 in 73% overall yield over 2 steps smoothly.
Scheme 7 Synthesis of hexasaccharide 2 by the route of III + II + I + II'' + II'
entry
donor
solvent
yield
90%
92%
91%
α/β
1/1.4
1:3
o
+
I'. Reagents and conditions: a) p-TolSCl, AgOTf, TTBP, CH
2
Cl
2
, -40 C to
o
room temperature. b) Et SiH, TfOH, -78 C, 5 min. c) 4, p-TolSCl, AgOTf,
CH
3
1
2
3
5
5
6
CH
Et
CH
2
Cl
2
o
o
2 2 3
Cl , -40 C to room temperature. d) i) NaOMe /CH OH, 40 C, 20 h; ii)
2
O
Pd(OH) /C, H , CH Cl /MeOH/H O (2/2/1), 2 d.
2
2
2
2
2
2
Cl
2
2:1
We then adopted the third synthetic route (III + II + I + II' +
II''+ I') (Scheme 6), making the two desired 1,2-cis glycosylations
at the first two steps. The assembly of trisaccharide backbone 27
was accomplished via the preactivation-based one-pot
glycosylation protocol in 79% isolated yield with high
α-stereoselectivities. After cleavage of the Bz groups in 27, the
trisaccharide acceptor 10 was obtained. The glycosylation of
acceptor 10 and donor 7 promoted by p-TolSCl/AgOTf offered the
undesired product that the rhamnose unit was connected at O4
position (compound 29) instead of O3 position (compound 28),
which was attributed to the less steric hindrance.
Conclusions
In conclusion, after exploring four synthetic routes towards
the hyperbranched hexasaccharide 2 attached to ATCV-1, it was
found that the order of the sugar residue added is important for
Scheme 6 The synthetic route of III + II + I + II' + II''+ I'. Reagents and
o
conditions: a) p-TolSCl, AgOTf, Et
2
O, then 11 or 9, -78 C to room
o
3 2 2
temperature. b) NaOMe/CH OH, 40 C, 10 h. c) p-TolSCl, AgOTf, 7, CH Cl ,
o
-
78 C to room temperature.
the
regio-selectivity and stereo-selectivity. The target oligosaccharide
was synthesized in 10% overall yield over 8 steps from
successful
oligosaccharide
assembly
with
good
2
monosaccharide building blocks by the strategy of III + II + I + II'' +
II' + I'. Our synthetic approach featured the use of p-tolyl
thioglycosides as the sole type of building blocks, the
three-component one-pot glycosylation, and the regio-selective
glycosylation. The disclosed approach towards the synthesis of
this new type of N-glycans will facilitate the in-depth studies of
their biological activities. This synthetic protocol also provides a
good reference example for other hyperbranched oligosaccharide
synthesis.
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1
3
Experimental
General information
All chemicals were purchased as reagent grade and used
without further purification. All solvents including CH
0.80 (d, J = 6.5 Hz, 3H, CH
3
); C NMR (101 MHz, CDCl
3
) δ 166.18,
1
1
1
1
9
7
6
65.49, 139.15, 138.78, 138.52, 138.38, 138.29, 137.42, 137.08,
33.10, 129.93, 129.85, 129.75, 129.29, 128.47, 128.42, 128.38,
28.31, 128.26, 128.17, 128.13, 128.03, 127.99, 127.57, 127.51,
27.48, 127.40, 127.18, 127.00, 126.42, 102.11, 98.56, 97.20,
6.05, 80.34, 80.22, 78.34, 76.25, 75.68, 74.58, 74.01, 73.29,
2.99, 72.62, 71.97, 71.86, 71.47, 70.37, 70.26, 69.60, 69.41,
2 2 3
Cl , CH CN,
DMF, Et O were dried according to standard procedures before
2
use. Molecular sieves were activated by heating prior to use. All
glycosylation reactions were carried out in oven-dried glassware
under argon atmosphere. Analytical thin layer chromatography
9.23, 64.68, 62.92, 15.74；HRMS (ESI) Calcd for C81H84NO17 [M +
+
NH
4
] : 1342.5734, Found: 1342.5752.
Benzyl
2,3,4,6-tetra-O-benzyl-α-D-galactopyranosyl)-(1→2)-(α-L-fucopy
ranosyl)-(1→3)-2-O-benzyl-4,6-O-benzylidene-α-D-glucopyranosi
de (10). To a solution of compound 27 (450 mg, 0.339 mmol) in
mixed solvent (5 mL, CH Cl /methanol 1/2), a saturated aqueous
2 2
solution of MeONa/MeOH (5.4 M, 0.3 ml, 1.70 mmol) was added.
(
TLC) was performed on aluminium sheets precoated with silica
gel 60 F254 (Merck), and the spots were detected under UV (254
nm) light and charred with a solution of Ce(NH (NO (0.50 g,
.9 mmol) and (NH Mo O (24.0 g, 19.4 mmol) in sulfuric
(
4
)
2
3 6
)
0
4
)
6
7 2
O24·4H
acid (5%, 500 mL). Column chromatography was carried out using
silica gel (200–300 mesh). Optical rotations were obtained on an
Autopol IV Automatic Polarimeter. H and C NMR spectra were
recorded on Avance Bruker III-400 or III-600 instruments at room
1
13
o
Then the mixture was heated at 40 C for 10 h. The reaction was
quenched with CO2. After removal of solvent, the crude product
was purified by column chromatography on silica gel (petroleum
ether/acetone/EtOAc, 2:1:1) to give compound 10 as a white
1
temperature in CDCl
3
or D
2
O. H NMR spectra were recorded with
TMS (tetramethylsilane, δ = 0 ppm) as internal in CDCl . The
3
1
13
solvent peak of H NMR was calibrated at 4.79 ppm for D
2
O.
(δ =
7.16 ppm). Assignments of resonances in H, C NMR spectra
C
21
D
1
foam (349 mg, 92% yield). [α]
= +9.8 (c = 0.44, CHCl
3
). H NMR
NMR spectra were reported relative to the signal of CDCl
7
3
(
(
2
400 MHz, CDCl
s, 1H), 5.46 (d, J = 3.5 Hz, 1H), 4.97 (d, J = 3.5 Hz, 1H), 4.88 (d, J =
.5 Hz, 1H), 4.85 (d, J = 2.5 Hz, 1H), 4.73 (d, J = 3.8 Hz, 1H), 4.69 (d,
J = 11.3 Hz, 1H), 4.65 – 4.54 (m, 4H), 4.49 (d, J = 11.4 Hz, 1H), 4.43
d, J = 12.3 Hz, 1H), 4.37 (d, J = 9.3 Hz, 1H), 4.34 – 4.17 (m, 7H),
3
) δ 7.48 - 7.42 (m, 2H), 7.37 – 7.11 (m, 35H), 5.51
1
13
were done using COSY, HSQC and HMBC experiments. HRMS
experiments were performed on a Bruker Apex IV FTMS
instrument or a Waters Xevo G2 Q-TOF mass spectrometer.
The following standard abbreviations are used to indicate
multiplicity: s = singlet, d = doublet, t = triplet, m = multiplet, dd =
doublet of doublets, dt = doublet of triplets, td = triplet of
doublets, and br = broad.
(
4
3
2
3
1
1
1
9
7
6
1
.10 – 4.02 (m, 2H), 3.98 (dd, J = 10.1, 2.6 Hz, 1H), 3.92 (s, 1H),
.91 – 3.84 (m, 1H), 3.80 (dd, J = 9.9, 3.5 Hz, 1H), 3.72 – 3.64 (m,
H), 3.59 - 3.50 (m, 2H), 3.44 - 3.37 (m, 2H), 1.09 (d, J = 6.6 Hz,
13
H); C NMR (101 MHz, CDCl
3
) δ 138.78, 138.65, 138.47, 138.16,
Benzyl
37.60, 137.53, 137.18, 128.97, 128.64, 128.62, 128.51, 128.47,
28.43, 128.40, 128.32, 128.29, 128.26, 128.14, 128.01, 127.87,
27.69, 127.65, 127.59, 127.37, 126.13, 101.48, 101.39, 97.49,
6.19, 80.98, 80.47, 80.09, 79.55, 74.92, 74.88, 74.73, 73.80,
3.36, 72.44, 72.28, 71.83, 70.46, 69.54, 69.30, 69.22, 68.68,
5.40, 62.51, 16.12；HRMS (ESI) Calcd for C67
(
2,3,4,6-tetra-O-benzyl-α-D-galactopyranosyl)-(1→2)-(3,4-di-O-b
enzoyl-α-L-fucopyranosyl)-(1→3)-2-O-benzyl-4,6-O-benzylidene-
α-D-glucopyranoside (27). A mixture of freshly activated 4 Å
molecular sieves (4.0 g), glycosyl donor 5 (297 mg, 0.460 mmol) in
anhydrous Et
argon atmosphere at room temperature. After cooling down to
78 °C for 5 min, p-TolSCl (73 mg, 62.3 μL, 0.459 mmol) was added
quickly followed by the addition of AgOTf (236 mg, 0.918 mmol)
dissolved in mixed solvent (4.8 mL, toluene/CH Cl 3:1). The
2
O (23 mL) was allowed to stir for 20 min under
+
H76NO15 [M + NH
4
] :
134.5209, Found: 1134.5197.
-
Synthesis of compounds 30 and 31. A mixture of freshly
activated 4 Å molecular sieves (1.0 g), glycosyl donor 4 (89 mg,
.157 mmol), glycosyl acceptor 10 (100 mg, 0.090 mmol) and
TTBP (47 mg, 0.189 mmol) in anhydrous CH Cl (9.0 ml) was
allowed to stir for 20 min under argon atmosphere at room
temperature. After cooling down to -40 °C for 10 min, p-TolSCl (30
mg, 25.2 μL, 0.188 mmol) was added quickly followed by the
addition of AgOTf (1.5 mL, 0.2 mol/L, toluene/CH
mixture was stirred and slowly warmed up to room temperature.
The mixture was then quenched by Et N and filtered through a
pad of Celite. After concentration, the residue was purified by
column chromatography on silica gel (petroleum ether/EtOAc 4:1
to toluene/acetonitrile 30:1) to give product 30 (85 mg, 61 % yield)
and byproduct 31 (27 mg, 15% yield).
2
2
0
resulting solution was stirred for 5 min. When TLC revealed that
donor 5 disappeared, glycosyl acceptor 11 (200 mg, 0.418 mmol)
dissolved in Et O (5.0 mL) was added. After 10 min TLC showed
2
that acceptor 11 disappeared. The resuling mixture was then
warmed up to room temperature for 20 min and then cooled
back to -78 °C for 5 min, p-TolSCl (66 mg, 57 μL, 0.418 mmol) was
added quickly followed by the addition of AgOTf (236 mg, 0.918
2
2
2 2
Cl 3:1). The
3
mmol) dissolved in mixed solvent (4.8 mL, toluene/CH
After another 5 min, a solution of acceptor 9 (187 mg, 0.418
mmol) in Et O (7 mL) was added slowly. After 10 min TLC showed
that acceptor 9 disappeared. The mixture then quenched by Et N.
2 2
Cl 3:1).
2
3
The resulting mixture was filtered through a pad of Celite and the
filtrate was concentrated. The residue was purified by column
chromatography on silica gel (petroleum ether/EtOAc, 8:1) to give
Benzyl
(
2,3,4,6-tetra-O-benzyl-α-D-galactopyranosyl)-(1→2)-[4-O-(2,3,4-
tri-O-benzoyl-β-D-xylopyranosyl)-(1→4)-α-L-fucopyranosyl]-(1→
)-2-O-benzyl-4,6-O-benzylidene-α-D-glucopyranoside
= +11.5 (c = 0.13, CHCl ). H NMR (600 MHz,
3
CDCl ) δ 7.99 (d, J = 7.3 Hz, 2H, Ar), 7.95 (d, J = 7.4 Hz, 2H, Ar),
.91 (d, J = 7.3 Hz, 2H, Ar), 7.57 – 7.48 (m, 2H, Ar), 7.43 – 7.35 (m,
H, Ar), 7.35 – 7.12 (m, 35H, Ar), 5.71 (t, J = 7.4 Hz, 1H, H-3 ),
2
D
1
product 27 as a white foam (437 mg, 79% yield). [α]
= -23.7 (c =
3
(30).
1
0
7
1
.30, CHCl
3
). H NMR (400 MHz, CDCl
3
) δ 7.90 – 7.84 (m, 2H, Ar),
21
D
1
White foam. [α]
3
.80 – 7.73 (m, 2H, Ar), 7.56 – 7.25 (m, 17H, Ar), 7.23 – 7.13 (m,
9H, Ar), 7.13 – 7.06 (m, 1H, Ar), 7.01 (t, J = 7.4 Hz, 2H, Ar), 6.85
7
7
5
3
5
II
(
d, J = 7.2 Hz, 2H, Ar), 5.89 (dd, J = 10.7, 3.3 Hz, 1H, H-3 ), 5.63 (d,
II‘‘
II
J = 3.6 Hz, 1H, H-1 ), 5.60 (s, 1H, PHCH), 5.49 (dd, J = 3.2, 1.0 Hz,
1
II
II‘‘
.45 (s, 1H, PHCH(O)), 5.44 – 5.39 (m, 2H, H-1 , H-2 ), 5.33 (d, J =
.5 Hz, 1H, H-1 ), 5.24 (td, J = 7.1, 4.6 Hz, 1H, H-4 ), 4.88 (d, J =
II
III
I
H, H-4 ), 5.29 (d, J = 3.4 Hz, 1H, H-1 ), 4.81 – 4.75 (m, 2H, H-1 ,
III
II‘‘
II
PHCH
PHCH
2
), 4.70 (q, J = 6.3 Hz, 1H, H-5 ), 4.65 (d, J = 12.4 Hz, 1H,
), 4.61 (dd, J = 10.7, 3.7 Hz, 1H, H-2 ), 4.56 (d, J = 12.0 Hz,
II‘‘
.6 Hz, 1H, H-1 ), 4.85 (d, J = 11.4 Hz, 1H, PHCH ), 4.82 (d, J = 11.7
2
), 4.74 (d, J = 11.7 Hz, 1H, PHCH ), 4.68 – 4.53 (m,
2
II
2
Hz, 1H, PHCH
H, PHCH ×4, H-1 ), 4.50 - 4.44 (m, 2H, PHCH
m, 6H, PHCH
I
2
1
H, PHCH
Hz, 1H, PHCH
2.0 Hz, 1H, PHCH
2
), 4.50 – 4.35 (m, 7H, PHCH
), 4.28 – 4.20 (m, 2H, PHCH
), 3.97 (td, J = 9.8, 4.7 Hz, 1H, H-5 ), 3.94 – 3.89
2
×6, H-3 ), 4.33 (d, J = 12.7
I
II‘‘
5
(
2
2
, H-5a ), 4.35 – 4.23
I
I
II
II
2
2
, H-6a ), 4.10 (d, J =
×4, H-3 , H-5 ), 4.18 (dd, J = 10.4, 2.7 Hz, 1H, H-3 ),
I
2
1
2
I
III
4
4
.15 (dd, J = 10.2, 4.8 Hz, 1H, H-6a ), 4.09 (t, J = 6.6 Hz, 1H, H-5 ),
.05 (dd, J = 10.1, 3.5 Hz, 1H, H-2 ), 4.03 – 3.96 (m, 2H, H-2 ,
H-3 ), 3.84 (td, J = 10.0, 4.9 Hz, 1H, H-5 ), 3.79 (s, 1H, H-4 ), 3.69
III
III
(m, 1H, H-5 ), 3.84 (dd, J = 10.1, 3.5 Hz, 1H, H-2 ), 3.82 – 3.67 (m,
I
I
I
I
I
I
I
I
III
III
4
3
H, H-2 , H-4 , H-6b , H-3 ), 3.45 (dd, J = 9.6, 7.4 Hz, 1H, H-6a ),
.42 (d, J = 1.5 Hz, 1H, H-4 ), 3.03 (dd, J = 9.6, 5.0 Hz, 1H, H-6b ),
III
I
III
III
III
This article is protected by copyright. All rights reserved.

II
I
II’
II
II
(
s, 1H, H-4 ), 3.65 (t, J = 10.3 Hz, 1H, H-6b ), 3.59 (dd, J = 12.3, 7.1
PHCH
4H, PHCH
3.98 (dd, J = 9.8, 2.6 Hz, 1H, H-3 ), 3.88 (td, J = 10.0, 4.9 Hz, 1H,
2
×2, H-5 ), 4.26 – 4.20 (m, 2H, H-2 , H-3 ), 4.20 – 4.13 (m,
II‘‘
I
I
I II III II’
Hz, 1H, H-5b , 3.57 – 3.51 (m, 2H, H-2 , H-4 ), 3.43 – 3.39 (m, 1H,
H-6a ), 3.39 – 3.34 (m, 1H, H-6b ), 0.80 (d, J = 6.5 Hz, 3H, CH
C NMR (151 MHz, CDCl
38.98, 138.53, 138.51, 138.27, 137.49, 137.21, 133.50, 133.47,
33.30, 130.05, 130.02, 129.97, 129.47, 129.45, 129.21, 129.07,
28.56, 128.54, 128.50, 128.48, 128.46, 128.45, 128.43, 128.34,
28.31, 128.28, 128.25, 128.11, 127.96, 127.88, 127.83, 127.66,
27.62, 127.55, 127.49, 127.40, 126.22, 101.78 (2C), 99.28, 98.00,
6.58, 83.60, 80.66, 80.65, 79.00, 76.72, 76.21, 75.21, 74.86,
3.36, 73.17, 73.15, 72.74, 72.49, 70.97, 70.80, 69.89, 69.80,
2
, H-6a , H-5 , H-5 ), 4.04 (dd, J = 9.3, 2.9 Hz, 1H, H-3 ),
III
III
III
3
);
1
3
I
II’’
II
3
) δ 165.65, 165.58, 165.08, 139.08,
H-5 ), 3.85 – 3.80 (m, 1H, H-5b ), 3.78 (s, 1H, H-4 ), 3.76 – 3.69 (m,
I III III III
1
1
1
1
1
9
7
6
3H, H-2 , H-2 , H-6a ), 3.67 (s, 1H, H-4 ), 3.59 (dd, J = 9.3, 6.4 Hz,
III I I
1H,H-6b ), 3.55 (t, J = 10.3 Hz, 1H, H-6b ), 3.49 – 3.42 (m, 2H, H-4 ,
II’
H-4 ), 3.20 (s, 3H, -OCH
6.5 Hz, 3H, CH
3
), 1.36 (d, J = 6.3 Hz, 3H, CH
); C NMR (151 MHz, CDCl ) δ 165.59, 165.50,
3
), 0.96 (d, J =
1
3
3
3
165.28, 165.22, 139.41, 139.22, 139.18, 138.90, 138.74, 138.69,
137.51, 137.26, 133.42, 133.22, 133.19, 133.12, 130.28, 130.18,
130.12, 130.09, 130.05, 129.96, 129.53, 129.43, 129.09, 128.56,
128.54, 128.45, 128.40, 128.38, 128.34, 128.31, 128.28, 128.24,
128.17, 128.03, 127.88, 127.73, 127.67, 127.62, 127.42, 127.39,
127.20, 127.11, 127.05, 126.31, 101.75, 101.36, 96.16, 96.05,
95.75, 93.46, 80.69, 80.44, 80.42, 80.10, 79.25, 78.13, 77.47,
75.69, 75.44, 74.67, 74.21, 73.30, 73.14, 72.87, 72.44, 71.83,
70.49, 70.04, 69.69, 69.41, 69.14, 68.83, 68.40, 67.59, 65.52,
9.44, 69.23, 69.21, 68.68, 65.76, 62.68, 61.76, 16.11；HRMS (ESI)
Calcd for C93
+
H
96NO22 [M + NH
4
] : 1578.6419, Found: 1578.6425.
Benzyl
(
2,3,4,6-tetra-O-benzyl-α-D-galactopyranosyl)-(1→2)-[3-O-(2,3,4-
tri-O-benzoyl-β-D-xylopyranosyl)-(1→3)-4-O-(2,3,4-tri-O-benzoyl
β-D-xylopyranosyl)-(1→4)-α-L-fucopyranosyl]-(1→3)-2-O-benzyl
21
4,6-O-benzylidene-α-D-glucopyranoside (31). White foam. [α]
-
-
-
D
=
62.60, 60.51, 56.89, 18.56, 16.52; HRMS (ESI) Calcd for
1
+
20.5 (c = 0.57, CHCl
3
). H NMR (600 MHz, CDCl
3
) δ 8.03 – 7.95 (m,
C
114
H
118NO27 [M + NH
4
] : 1932.7886, Found: 1932.7917.
H, Ar), 7.91 (d, J = 7.0 Hz, 2H, Ar), 7.83 (t, J = 8.5 Hz, 4H, Ar), 7.58
7.50 (m, 2H, Ar), 7.51 – 7.26 (m, 27H, Ar), 7.25 – 7.07 (m, 24H,
Benzyl
(2,3,4,6-tetra-O-benzyl-α-D-galactopyranosyl)-(1→2)-[3-O-(3-O-
methyl-4-O-benzyl-2-O-benzoyl-α-L-rhamnopyranosyl)-(1→3)-4-
O-(2,3,4-tri-O-benzoyl-β-D-xylopyranosyl)-(1→4)-α-L-fucopyrano
syl]-(1→3)-2,6-di-O-benzyl-α-D-glucopyranoside (32). A mixture
of freshly activated 4 Å molecular sieves (200 mg), compound 21
.78 (m, 2H), 4.72 (d, J = 3.6 Hz, 1H), 4.65 – 4.52 (m, 3H), 4.53 –
.40 (m, 6H), 4.40 – 4.33 (m, 2H), 4.33 – 4.07 (m, 7H), 4.07 – 4.02
(60 mg, 0.031 mmol), Et
3
SiH (21.8 mg, 30.0 μL, 0.188 mmol) in
(
–
m, 2H), 3.92 – 3.83 (m, 2H), 3.80 (s, 1H), 3.69 – 3.61 (m, 1H), 3.61
anhydrous CH Cl (2.0 mL) was allowed to stir for 10 min under
argon atmosphere at room temperature. After cooling down to
-78 °C for 10 min, TfOH (10.0 μL) was added. The mixture was
3
stirred for 5 min, then quenched with Et N and filtered through a
2
2
3.54 (m, 2H), 3.45 (dd, J = 12.9, 5.0 Hz, 1H), 3.40 (t, J = 8.0 Hz,
1
3
1
H), 3.34 (dd, J = 8.7, 6.1 Hz, 1H), 0.94 (d, J = 6.7 Hz, 3H); C NMR
) δ 165.73, 165.60, 165.41, 165.37, 165.32,
(151 MHz, CDCl
3
1
1
1
1
1
1
1
7
7
6
2
65.06, 139.12, 138.86, 138.83, 138.32, 137.57, 137.31, 133.44,
33.38, 133.31, 133.19, 133.12, 133.00, 130.20, 130.10, 130.06,
30.01, 129.95, 129.79, 129.73, 129.70, 129.63, 129.49, 129.33,
29.24, 128.95, 128.73, 128.59, 128.56, 128.54, 128.51, 128.48,
28.39, 128.35, 128.30, 128.27, 128.21, 128.18, 128.12, 127.99,
27.93, 127.63, 127.58, 127.50, 127.47, 127.38, 127.35, 126.26,
01.56, 100.96, 98.62, 96.93, 96.92, 80.72, 80.17, 78.97, 76.53,
5.51, 74.91, 74.79, 73.47, 73.39, 72.87, 72.56, 70.60, 70.44,
pad of Celite. After concentration, the residue was purified by
column chromatography on silica gel (petroleum ether/EtOAc, 4:1)
21
to give 32 as a white foam (52 mg, 85% yield). [α]
3 3
CHCl ). H NMR (600 MHz, CDCl ) δ 8.05 (t, J = 6.5 Hz, 4H), 7.98 (t,
D
= -7.9 (c = 0.14,
1
J = 7.6 Hz, 4H), 7.59 – 7.52 (m, 2H), 7.52 – 7.46 (m, 1H), 7.47 –
7.37 (m, 5H), 7.36 – 7.06 (m, 44H), 5.79 (t, J = 7.1 Hz, 1H), 5.74 (dd,
J = 2.8, 1.5 Hz, 1H), 5.58 (dd, J = 7.1, 5.4 Hz, 1H), 5.48 – 5.42 (m,
1H), 5.39 (d, J = 2.3 Hz, 1H), 5.20 (s, 1H), 5.00 (d, J = 3.4 Hz, 1H),
4.97 (br., 1H), 4.88 (d, J = 13.3 Hz, 1H), 4.85 – 4.80 (m, 2H), 4.78 (d,
J = 11.5 Hz, 1H), 4.69 (d, J = 13.3 Hz, 1H), 4.67 – 4.54 (m, 6H), 4.54
– 4.46 (m, 3H), 4.44 – 4.39 (m, 3H), 4.37 (dd, J = 10.1, 2.6 Hz, 1H),
4.35 – 4.19 (m, 5H), 4.12 (dd, J = 10.3, 2.6 Hz, 1H), 4.10 (s, 1H),
4.00 (d, J = 7.5 Hz, 1H), 3.92 (dd, J = 10.2, 3.4 Hz, 1H), 3.88 (dd, J =
10.3, 2.4 Hz, 1H), 3.79 (br., 1H), 3.73 (s, 1H), 3.70 – 3.59 (m, 3H),
3.52 (t, J = 8.4 Hz, 1H), 3.48 (t, J = 9.5 Hz, 1H), 3.40 (t, J = 8.6 Hz,
1H), 3.37 (dd, J = 9.7, 3.7 Hz, 1H), 3.28 (dd, J = 9.1, 5.1 Hz, 1H),
0.30, 70.26, 69.87, 69.80, 69.47, 69.17, 68.74, 68.37, 62.84,
+
1.65, 60.47, 16.33; HRMS (ESI) Calcd for C119
022.7628, Found: 2022.7569.
Benzyl
H116NO29 [M + NH
4
] :
(
2,3,4,6-tetra-O-benzyl-α-D-galactopyranosyl)-(1→2)-[3-O-(3-O-
methyl-4-O-benzyl-2-O-benzoyl-α-L-rhamnopyranosyl)-(1→3)-4-
O-(2,3,4-tri-O-benzoyl-β-D-xylopyranosyl)-(1→4)-α-L-fucopyrano
syl]-(1→3)-2-O-benzyl-4,6-O-benzylidene-α-D-glucopyranoside
1
3
(
21). A mixture of freshly activated 4 Å molecular sieves (500 mg),
glycosyl donor 7 (55 mg, 0.115 mmol), glycosyl acceptor 30 (60
mg, 0.038 mmol) in anhydrous Et O (4.0 mL) was allowed to stir
3.21 (s, 3H), 1.26 (d, J = 6.2 Hz, 3H), 1.24 (d, J = 6.6 Hz, 3H); C
NMR (151 MHz, CDCl ) δ 165.77, 165.72, 165.53, 165.31, 139.43,
3
2
139.33, 139.00, 138.84, 138.82, 138.56, 138.39, 137.77, 133.60,
133.37, 133.33, 133.14, 130.34, 130.15, 130.12, 129.99, 129.96,
129.67, 129.56, 129.22, 128.58, 128.54, 128.48, 128.42, 128.40,
128.29, 128.26, 128.24, 128.22, 127.97, 127.83, 127.80, 127.76,
127.64, 127.58, 127.47, 127.46, 127.39, 127.30, 127.26, 101.95,
101.95, 98.87, 96.89, 95.08, 84.26, 80.18, 79.96, 79.34, 76.16,
75.97, 75.44, 74.69, 74.04, 73.47, 73.46, 73.23, 72.78, 71.24,
70.88, 70.73, 70.58, 69.99, 69.91, 69.75, 69.62, 69.28, 69.18,
for 20 min under argon atmosphere at room temperature. After
cooling down to -40 °C for 10 min, p-TolSCl (22 mg, 18.5 μL, 0.138
mmol) was added quickly followed by the addition of AgOTf (1.2
ml, 0.2 mol/L, toluene/Et
slowly warmed up to room temperature. The mixture was
quenched with Et N and was filtered through a pad of Celite.
2
O 3:1). The mixture was stirred, then
3
After concentration, the residue was purified by column
chromatography on silica gel (petroleum ether/EtOAc, 5:1) to give
68.09, 67.54, 61.60, 57.16, 18.66, 16.30; HRMS (ESI) Calcd for
2
D
1
+
2
1 as a white foam (57 mg, 78% yield). [α]
= -3.6 (c = 0.14, CHCl
) δ 8.06 (d, J = 7.3 Hz, 2H, Ar), 8.03 (d, J =
.3 Hz, 2H, Ar), 7.91 (d, J = 8.1 Hz, 4H, Ar), 7.54 (t, J = 7.3 Hz, 2H,
Ar), 7.49 – 7.26 (m, 24H, Ar), 7.25 – 7.09 (m, 24H, Ar), 7.05 – 7.00
3
).
C
114
H
120NO27 [M + NH
4
] : 1934.8042, Found: 1934.8093.
1
H NMR (600 MHz, CDCl
7
3
Benzyl
(2,3,4,6-tetra-O-benzyl-α-D-galactopyranosyl)-(1→2)-[3-O-(3-O-
methyl-4-O-benzyl-2-O-benzoyl-α-L-rhamnopyranosyl)-(1→3)-4-
II’
II
(
m, 2H, Ar), 5.69 (s, 1H, H-2 ), 5.58 (d, J = 3.0 Hz, 1H, H-1 ), 5.56 (t, O-(2,3,4-tri-O-benzoyl-β-D-xylopyranosyl)-(1→4)-α-L-fucopyrano
II’’
J = 5.7 Hz, 1H, H-3 ), 5.40 (s, 1H, PHCH(O)), 5.32 (dd, J = 5.6, 4.3
syl]-(1→3)-2,6-di-O-benzyl-4-O-(2,3,4-tri-O-benzoyl-β-D-xylopyra
nosyl)-(1→4)-α-D-glucopyranoside (33). A mixture of freshly
activated 4 Å molecular sieves (300 mg), glycosyl donor 4 (44 mg,
II’’
II’
II’’
Hz, 1H, H-2 ), 5.18 – 5.13 (m, 2H, H-1 , H-4 ), 5.00 (d, J = 3.5 Hz,
III
I
1
H, H-1 ), 4.85 (d, J = 3.6 Hz, 1H, H-1 ), 4.84 – 4.79 (m, 2H, PHCH ,
2
II’’
H-1 ), 4.72 – 4.66 (m, 2H, PHCH
2
×2), 4.63 – 4.40 (m, 8H, PHCH
2
×7, 0.078 mmol), glycosyl acceptor 32 (30 mg, 0.016 mmol) and TTBP
II’’
I
H-5a ), 4.38 – 4.32 (m, 2H, PHCH
2
, H-3 ), 4.32 – 4.26 (m, 3H, (23 mg, 0.093 mmol) in anhydrous CH Cl (2.0 mL) was allowed to
2
2
This article is protected by copyright. All rights reserved.

stir for 20 min under argon atmosphere at room temperature.
After cooling down to -40 °C for 10 min, p-TolSCl (15 mg, 12.5 μL,
99.01, 98.99, 97.88, 97.77, 96.73, 96.21, 96.17, 92.83, 80.64,
76.66, 76.24, 76.16, 75.79, 75.63, 75.58, 74.48, 74.43, 74.36,
73.99, 73.88, 73.35, 72.70, 72.68, 72.43, 72.37, 71.64, 71.38,
70.32, 70.22, 69.96, 69.46, 69.13, 68.91, 68.71, 67.04, 66.98,
0
(
.093 mmol) was added quickly followed by the addition of AgOTf
0.8 mL, 0.2 mol/L, toluene/CH Cl , 3:1). The mixture was stirred,
then slowly warmed up to room temperature. The mixture was
quenched with Et N and was filtered through a pad of Celite.
2
2
66.38, 65.82, 65.69, 62.16, 62.07, 60.25, 60.14, 56.60, 17.47,
-
3
15.54, 15.52；HRMS (ESI) Calcd for C36
H
61
O
29 [M + HCOO] :
After concentration, the residue was purified by column
chromatography on silica gel (petroleum ether/EtOAc, 4:1 to 3:1)
957.3304, Found: 957.3305.
21
to give 33 as a white foam (18 mg, 47% yield). [α]
D
= +13.0 (c =
) δ 8.08 (d, J = 8.0 Hz, 2H,
Ar), 8.05 (d, J = 7.4 Hz, 2H, Ar), 7.98 – 7.94 (m, 2H, Ar), 7.94 – 7.91
m, 2H, Ar), 7.85 (d, J = 7.7 Hz, 2H, Ar), 7.81 (d, J = 7.3 Hz, 2H, Ar),
Supporting Information
The supporting information for this article is available on the
WWW under https://doi.org/10.1002/cjoc.2018xxxxx.
1
0
3 3
.10, CHCl ). H NMR (600 MHz, CDCl
(
7
2
.58 – 7.26 (m, 35H, Ar), 7.25 – 7.07 (m, 26H, Ar), 7.03 – 6.98 (m,
II II’
H, Ar), 5.76 – 5.73 (m, 2H, H-1 , H-2 ), 5.66 (t, J = 6.6 Hz, 1H, Acknowledgement
II’’
I’
H-3 ), 5.57 (t, J = 9.4 Hz, 1H, H-3 ), 5.39 (dd, J = 6.6, 5.1 Hz, 1H,
H-2 ), 5.35 (d, J = 1.0 Hz, 1H, H-1 ), 5.20 (dd, J = 9.1, 7.4 Hz, 1H,
H-2 ), 5.18 – 5.15 (m, 1H, H-4 ), 5.05 – 4.97 (m, 3H, H-1 , H-1 ,
H-4 ), 4.85 – 4.80 (m, 2H, PHCH
This work was taken in part from the M.Sc. thesis of Y.-S.W,
Peking University, May of 2018. The work was financially
supported by grants from the National Key R&D Program of China
(Grant No. 2018YFA0507602), the National Natural Science
Foundation of China (21572012, 21772006) and the State Key
Laboratory of Drug Research (SIMM1803KF-02).
II’’
II’
I’
II’’
III
II’’
I’
I
2
, H-1 ), 4.80 – 4.70 (m, 3H, PHCH
2
,
II
I’
II
I’
H-5 , H-5a ), 4.70 – 4.59 (m, 4H, PHCH ×2, H-3 , H-1 ), 4.59 – 4.53
2
II’’
II
(
m, 2H, PHCH , H-5a ), 4.52 – 4.22 (m, 13H, PHCH ×11, H-2 ,
2
2
II’ I III II
H-5 ), 4.19 – 4.11 (m, 2H, H-3 , H-5 ), 4.06 (s, 1H, H-4 ), 4.04 –
III
II’
I
3
.99 (m, 2H, H-3 , H-3 ), 3.97 (t, J = 9.6 Hz, 1H, H-4 ), 3.87 – 3.79 References
II’’
III
(br, 1H, H-5b ), 3.77 (dd, J = 9.0, 2.5 Hz, 1H, H-2 ), 3.75 – 3.66 (m,
I III III I III
[
1] Apweiler, R.; Hermjakob, H.; Sharon, N. Biochim. Biophys. Acta. 1999,
1473, 4.
3
3
1
H, H-2 , H-4 , H-6a ), 3.66 – 3.61 (m, 2H, H-6a , H-6b ), 3.51 –
I II’ I I’
.45 (m, 2H, H-5 , H-4 ), 3.33 – 3.18 (m, 5H, H-6b , H-5b , -OCH
3
),
); C NMR
) δ 165.85, 165.69, 165.52, 165.46, 165.17,
13
.38 (d, J = 6.1 Hz, 3H, CH
3
), 1.33 (d, J = 6.6 Hz, 3H, CH
3
[2] (a) Dwek, R. A. Chem Rev. 1996, 96, 683. (b) Molinari, M.; Helenius, A.
Nature. 1999, 402, 90. (c) Maverakis, E.; Kim, K.; Shimoda, M.; Gershwin,
M. E.; Patel, F.; Wilken, R.; Raychaudhuri, S.; Ruhaak, L. R.; Lebrilla, C. B. J.
Autoimmun. 2015, 57, 1. (d) Taniguchi, N.; Kizuka, Y. Adv. Cancer Res.
(151 MHz, CDCl
3
1
1
1
1
1
1
1
8
7
6
5
2
64.93, 164.54, 139.58, 139.40, 139.24, 139.01, 138.83, 138.74,
38.01, 137.49, 133.29, 133.11, 133.05, 132.73, 130.80, 130.24,
30.17, 130.14, 130.10, 129.97, 129.90, 129.84, 129.80, 129.72,
29.57, 129.27, 129.19, 128.95, 128.53, 128.50, 128.42, 128.39,
28.36, 128.34, 128.29, 128.23, 128.21, 128.19, 128.11, 128.10,
27.81, 127.71, 127.65, 127.56, 127.46, 127.30, 127.27, 127.16,
27.03, 101.88, 100.60, 95.41, 95.40, 94.79, 93.22, 81.36, 80.94,
0.50, 79.04, 77.65, 75.72, 75.12, 74.86, 74.37, 73.76, 73.61,
3.29, 72.94, 72.36, 71.90, 71.34, 70.73, 70.52, 70.28, 69.89,
2015, 126, 11. (e) Helenius, A.; Aebi, M. Science. 2001, 291, 2364.
[
[
3] (a) Strasser, R. Glycobiology. 2016, 26, 926. (b) Gomord, V.; Fitchette,
A.-C.; Menu-Bouaouiche, L.; Saint-Jore-Dupas, C.; Plasson, C.; Michaud,
D.; Faye, L. Plant Biotechnol. J. 2010, 8, 564.
4] (a) De Castro, C.; Molinaro, A.; Piacente, F.; Gurnon, J. R.; Sturiale, L.;
Palmigiano, A.; Lanzetta, R.; Parrilli, M.; Garozzo, D.; Tonetti, M. G.; Van
Etten, J. L. Proc. Natl. Acad. Sci. USA. 2013, 110, 13956. (b) De Castro, C.;
Speciale, I.; Duncan, G.; Dunigan, D. D.; Agarkova, I.; Lanzetta, R.; Sturiale,
L.; Palmigiano, A.; Garozzo, D.; Molinaro, A.; Tonetti, M.; Van Etten, J. L.
Angew. Chem. Int. Ed. 2016, 55, 654. (c) peciale, I.; Agarkova, I.; Duncan,
G. A.; Van Etten, J. L.; De Castro, C. Anton. Leeuw. Int. J. Gen. Mol. 2017,
9.50, 69.15, 69.02, 68.89, 67.65, 67.07, 65.89, 62.46, 61.20,
+
6.99, 18.13, 16.41; HRMS (ESI) Calcd for C140
378.9251, Found: 2378.9221.
H140NO34 [M + NH
4
] :
(
3-O-Methyl-α-L-rhamnopyranosyl)-(1→3)-[4-O-(β-D-xylopyr
anosyl)-(1→4)-2-O-(α-D-galactopyranosyl)-(1→2)-α-L-fucopyran
osyl]-(1→3)-4-O-(β-D-xylopyranosyl)-D-glucopyranose (2). To a
solution of compound 33 (23.0 mg, 0.010 mmol) in mixed solvent
110, 1391.
(
2 2
2 mL, CH Cl /MeOH, 1/2), a saturated aqueous solution of
[
5] Werz, D. B.; Castagner, B.; Seeberger, P. H. J. Am. Chem. Soc. 2007, 129,
2770.
MeONa/MeOH (0.1 mL, 5.4 M) was added. Then the mixture was
o
heated at 40 C for 20 h. The reaction was neutralized by CO2.
After removal of solvent, the crude product was purified by gel
filtration (Sephadex LH-20, CH Cl /MeOH, 1:1) to give an
[
[
6] Li, Q.-J; Guo, Z.-W. Org. Lett. 2017, 19, 6558.
7] Sun, B.; Srinivasan, B.; Huang, X.-F. Chem. Eur. J. 2008, 14, 7072.
2
2
intermidiate. This intermidiate product was dissolved in mixed
solvent (5 mL, CH Cl /MeOH/H O, 2/2/1) with the addition of
Pd(OH) /C (30 mg, 20% Pd content), stirred under an atmosphere
[8] Kasai, A.; Arafuka, S.; Koshiba, N.; Takahashi, D.; Toshima, K. Org.
Biomol. Chem. 2015, 13, 10556.
2
2
2
2
[
9] Yolken, R. H.; Jones-Brando, L.; Dunigan, D. D.; Kannan, G.; Dickerson,
of hydrogen (0.4 MPa) for 2 d at room temperature, then filtered
through a pad of Celite. After concentration, the residue was
purified by gel filtration (Sephadex LH-20, MeOH) to give 2 as a
F.; Severance, E.; Sabunciyan, S.; Talbot, C. C., Jr.; Prandovszky, E.; Gurnon,
J. R.; Agarkova, I. V.; Leister, F.; Gressitt, K. L.; Chen, O.; Deuber, B.; Ma, F.;
Pletnikov, M. V.; Van Etten, J. L. Proc. Natl. Acad. Sci. USA. 2014, 111,
1
white foam (5.0 mg, 73% yield over two steps, α : β = 1:1). H
II
16106.
NMR (600 MHz, D
2
O) δ 5.69 (d, J = 4.0 Hz, 0.5H, H-1 ), 5.63 (d, J =
II
III
4
.0 Hz, 0.5H, H-1 ), 5.27 (s, 1H, H-1 ), 5.18 (d, J = 3.6 Hz, 0.5H,
H-1 ), 5.14 (d, J = 3.2 Hz, 1H, H-1 ), 4.65 (d, J = 8.0 Hz, 0.5H,
[10] Petro, M. S.; Agarkova, I. V.; Petro, T. M. J. Neuroimmun. 2016, 297,
I(α)
II‘
46.
I(β)
II‘‘
I‘
H-1 ), 4.46 (d, J = 7.6 Hz, 1H, H-1 ), 4.42 (d, J = 7.8 Hz, 1H, H-1 ),
[
11] Huang, X.-F.; Huang, L.-J.; Wang, H.-S.; Ye, X.-S. Angew. Chem. Int. Ed.
004, 43, 5221.
II
II
4
(
.41 – 4.37 (m, 1H, H-3 ), 4.27 (d, J = 2.3 Hz, 1H, H-4 ), 4.26 – 4.21
2
II II‘ II‘ I‘
m, 2H, H-2 , H-2 ), 4.19 – 4.12 (m, 2H, H-5 , H-5a ), 4.11 – 4.06
I
(
α
)
I
(
β
)
[12] During the preparation of our manuscript, Lowary’s work on the
synthesis of 1d appeared in Chemistry - A European Journal by the
different strategy in 16 steps and 13% overall yield. See: Lin, S.-C.; Lowary,
T. L. Chem. Eur. J. 2018, 24, 16992.
(
m, 1H, H-3 ), 4.06 – 4.01 (m, 1H), 4.01 – 3.87 (m, 4H, H-3
,
II‘‘
I(α)
III
H-5a ), 3.87 – 3.78 (m, 4H, H-2 , H-2 ), 3.75 – 3.67 (m, 3H), 3.64
I(β)
II‘
–
4
3.60 (m, 1H), 3.56 – 3.48 (m, 3H, H-2 , H-4 ), 3.48 – 3.44 (m,
II‘ II‘‘ II‘‘
H), 3.44 – 3.38 (m, 2H, H-3 , H-2 ), 3.34 – 3.24 (m, 2H, H-5b ,
I‘ I‘
H-5b ), 3.19 – 3.13 (m, 1H, H-2 ), 1.37 - 1.34 (m, 3H, CH
3
), 1.33 (d,
[13] (a) Wang, P.; Zhu, J.; Yuan, Y.; Danishefsky, S. J. J. Am. Chem. Soc.
1
3
J = 6.2 Hz, 3H, CH )； C NMR (151 MHz, D O) δ 105.06, 103.25,
3
2
2009, 131, 16669. (b) Walczak, M. A.; Hayashida, J.; Danishefsky, S. J. J.
This article is protected by copyright. All rights reserved.

Am. Chem. Soc. 2013, 135, 4700.
14] (a) Wu, Y.; Xiong, D.-C.; Chen, S.-C.; Wang, Y.-S.; Ye, X.-S. Nat.
Lourenco, E. C.; Rita Ventura, M. Tetrahedron 2013, 69, 7090. (c)
Ustyuzhanina, N.; Krylov, V.; Grachev, A.; Gerbst, A.; Nifantiev, N.
Synthesis 2006, 23, 4017.
[
Commun. 2017, 8, 14851. (b) Zhang, G.-L.; Wei, M.-M.; Song, C.-C; Ma,
Y.-F.; Zheng, X.-J.; Xiong, D.-C.; Ye, X.-S. Org. Chem. Front. 2018, 5, 2179. (c)
Zhang, G.-L.; Yang, L.; Zhu, J.-J; Wei, M.-M; Yan, W.-J; Xiong, D.-C.; Ye, X.-S.
Chem. Eur. J. 2017, 23, 10670. (d) Wang, D.; Xiong, D.-C.; Ye, X.-S. Chin.
Chem. Lett. 2018, 29, 1340.
(
The following will be filled in by the editorial staff)
Manuscript received: XXXX, 2017
Revised manuscript received: XXXX, 2017
Accepted manuscript online: XXXX, 2017
Version of record online: XXXX, 2017
[
[
15] Lian, G.; Zhang, X.; Yu, B. Carbohydr. Res. 2015, 403, 13.
16] (a) Zhou, J.; Yang, L.; Hu, W. J. Org. Chem. 2014, 79, 4718. (b)
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Entry for the Table of Contents
Page No.
Total Synthesis of
a Hyperbranched
N-Linked Hexasaccharide Attached to
ATCV-1 Major Capsid Protein without
Precedent
Text for Table of Contents.
Yong-Shi Wang, Yong Wu, De-Cai Xiong,
and Xin-Shan Ye*
This article is protected by copyright. All rights reserved.