Synthesis of 4,5-disubstituted-3-deoxy-d-manno-octulosonic acid (Kdo) derivatives

Article abstract of DOI:10.1016/j.tet.2014.04.024

In this study, a new synthetic approach to 4,5-branched Kdo trisaccharides based on the common acceptor Kdo(α2-4)Kdo was developed. The synthesis of three types of 4,5-branched trisaccharides, Hep(α1-5)[Kdo(α2-4)]Kdo, Man(α1-5)[Kdo(α2-4)]Kdo, and GalNAc(α

Full text of DOI:10.1016/j.tet.2014.04.024

Tetrahedron 70 (2014) 3675e3682
Contents lists available at ScienceDirect
Tetrahedron
journal homepage: www.elsevier.com/locate/tet
Synthesis of 4,5-disubstituted-3-deoxy-
(Kdo) derivatives
D-manno-octulosonic acid
Ruiqin Yi a, Atsushi Ogaki b, Mayumi Fukunaga b, Hiromitsu Nakajima b,
,
Tsuyoshi Ichiyanagi b
*
a The United Graduate School of Agricultural Sciences, Tottori University, 4-101 Koyama-minami, Tottori 680-8553, Japan
b Dept of Life and Food Sciences, Faculty of Agriculture, Tottori University, 4-101 Koyama-minami, Tottori 680-8553, Japan
a r t i c l e i n f o
a b s t r a c t
Article history:
In this study, a new synthetic approach to 4,5-branched Kdo trisaccharides based on the common ac-
Received 10 December 2013
Received in revised form 7 April 2014
Accepted 8 April 2014
ceptor Kdo(
Hep( 1-5)[Kdo(
in good yield and high
a
2-4)Kdo was developed. The synthesis of three types of 4,5-branched trisaccharides,
2-4)]Kdo, Man( 1-5)[Kdo( 2-4)]Kdo, and GalNAc( 1-5)[Kdo( 2-4)]Kdo, was achieved
-selectivity.
a
a
a
a
a
a
a
Available online 15 April 2014
Ó 2014 Elsevier Ltd. All rights reserved.
Keywords:
3-Deoxy-D-manno-2-octulosonic acid
Lipopolysaccharide
Lipooligosaccharide
4,5-Branched structure
Inner-core oligosaccharide
1. Introduction
Previously, we have reported the synthesis of the Kdo derivative
-mannose and the preparation of 2-4 and 2-8 linked Kdo
from
D
Lipopolysaccharide (LPS) and lipooligosaccharide (LOS) are
produced by gram-negative bacteria on their outer membrane and
play an important role in the mechanism of bacterial infection. LPS
is composed of O-specific polysaccharide, a core oligosaccharide
(core OS), and lipid A, whereas LOS lacks an O-antigen.1 The lipid A
moiety causes the biological toxicity of LPS/LOS;2 although the
function of the core oligosaccharide of LPS/LOS is still unknown.
Recently, it has been reported that human antibodies recognized
a core OS of LOS derived from pathogenic strains of bacteria.3 Thus,
the core OS is a target for vaccine development.
disaccharides.7 To extend the utility of this synthesis, we prepared
the 4,5-branched Kdo trisaccharides by glycosylation of the 5-OH
group of the 2-4 linked Kdo disaccharide using an approach dif-
ferent from Paulsen’s method. Three types of 4,5-branched Kdo
trisaccharide were synthesized through this new route.
2. Results and discussion
2.1. Synthesis of a2-4 linked Kdo disaccharide
The core OS can be further subdivided into a highly conserved
inner core and a structurally variable region. The unique compo-
nent of the inner core is 2-keto-3-deoxy-a-D-manno-octulosonic
acid (Kdo). The inner core of many LPS/LOSs is composed of a 4,5-
branched Kdo structure. For example, the inner core of Neisserial
For the synthesis of the 4,5-branched trisaccharide, 2-4 linked
Kdo acceptor 6
was prepared from common intermediate 1.7
Previously, we reported the regioselective glycosylation of glyco-
syl fluoride 3 with 4,5-diol acceptor 2, although we did not in-
vestigate the limitations of this reaction. Therefore, several types of
glycosyl donors (3 , 4, 5) were examined.
Kdo donors 4 and 5 were synthesized as follows. Treatment of
compound 1 with 2,2,2-trifluoro-N-phenylacetimidoyl chloride in
the presence of potassium carbonate gave the N-phenyl tri-
fluoroacetimidate 4 in quantitative yield.8 However, the reaction
needed 1 week to reach completion. The reaction for preparing the
Kdo trichloroacetimidate donor also demanded a week. This
showed that the reactivity of the anomeric hydroxyl group of the
Kdo derivatives was lower than that of aldose because of steric
a
a
LOS contains the branched Kdo trisaccharide, Hep(a1-5)[Kdo(a2-
4)]Kdo.4 Although many chemical syntheses of core LPS/LOS have
been reported,5 only Paulsen et al. have described the synthesis of
b
the 4,5-branched Kdo structure.6 They installed the
L
-glycero-
manno-heptopyranosyl donor (Hep) on the 5-OH of the Kdo ac-
ceptor to form a Hep( 1-5)Kdo dimer and then linked a Kdo donor
a-D-
a
to the 4-OH of the Kdo moiety.
* Corresponding author. Fax: þ81 857 31 5347; e-mail address: yanagi@muses.
tottori-u.ac.jp (T. Ichiyanagi).
0040-4020/$ e see front matter Ó 2014 Elsevier Ltd. All rights reserved.
http://dx.doi.org/10.1016/j.tet.2014.04.024

3676
R. Yi et al. / Tetrahedron 70 (2014) 3675e3682
hindrance and low nucleophilicity. Dibenzyl phosphite 5 was pre-
pared in moderate yield (56%) from compound 1 with 1H-tetrazole
and dibenzyl N,N-diisopropylphosphoramidite (DDP) (Scheme 1).9
Table 2. The reaction of heptosyl trichloroacetimidate 812 with ac-
ceptor 6
in the presence of 0.04 equiv of TMSOTf at 0 ꢀC gave the
corresponding 4,5-branched trisaccharide, Hep( 1-5)[Kdo( 2-4)]
a
a
a
Kdo (11), in only 10% yield, and orthoester 12 was the major product
(35%). To reduce the formation of 12, the reaction temperature was
raised to room temperature (entry 2). Correspondingly, the yield of
orthoester 12 reduced to 28%, and that of the target Hep(
a1-5)
[Kdo( 2-4)]Kdo (11) increased to 28%. To suppress the formation of
a
orthoester 12 further, more TMSOTf should be used, because the
orthoester is unstable in acid.13 Increasing the amount of TMSOTf
(entry 3) afforded trisaccharide 11 in good yield (87%) and only
a small amount of orthoester 12 was detected (3%).
The 4,5-branched structure of 11 was determined by 2D NMR
analysis (COSY, HMQC, and HMBC). From the COSY and HMBC
spectra, we were able to identify the cyclic proton and carbon atoms
of each residue of 11. The newly formed 1-5 linkage was identified
by HMBC analysis. Fig. 1 shows part of the HMBC spectrum. The
cross-relay peaks in the HMBC spectrum (Kdo H-5I/Hep C-1III, Hep
H-1III/Kdo C-5I) confirmed that heptosyl donor 8 is linked to the 5-
position of acceptor 6a. Moreover, the anomeric configuration was
1
determined from the JC-1,H-1 value.14 The coupling constant be-
tween H-1III and C-1III ð JHꢁ1
¼ 178 HzÞ of the Hep residue
1
Scheme 1. Conditions: (a) DAST,
fluoroacetimidoyl chloride, K2CO3, CH2Cl2, rt, 7 days, quant,
DDP, CH2Cl2, 0 ꢀC/rt, 3 h, 56%,
0
ꢀC, 0.5 h, 81%,
a
/
b
a/b
¼3:1; (b) N-phenyl tri-
III;Cꢁ1III
suggested that the newly formed glycosidic bond was an
a
-linkage.
2-4)]Kdo, was successfully
synthesized from the Kdo dimer with a heptosyl donor.
Following the synthesis of Hep( 1-5)[Kdo( 2-4)]Kdo (11), other
4,5-branched Kdo trisaccharides were also synthesized by the same
¼3:2; (c) 1H-tetrazole,
a
/
b¼23:1. DAST: N,N-diethylaminosulfur trifluoride;
Thus, the trisaccharide, Hep(a1-5)[Kdo(a
DDP: dibenzyl N,N-diisopropylphosphoramidite.
a
a
Next, glycosylation of 4,5-diol acceptor 2 with these glycosyl
donors was examined (Scheme 2). The results are summarized in
Table 1. Using b-fluoride 3b with boron trifluoride as an activator
route with 6a as an acceptor. By coupling 6a with mannosyl tri-
gave a moderate yield (entry 3), whereas using TMSOTf as a pro-
moter gave a poor yield (entry 4). The longer reaction time and
Table 1
Glycosylation of Kdo donors 3e5 with 4,5-diol acceptor 2
higher reaction temperature also suggest that the reactivity of
fluoride was lower than that of -fluoride. In contrast, the com-
bined promoter Cp2HfCl2eAgOTf10 readily converted fluoride 3
to
glycal 7 (90%, entry 2). The use of N-phenyl trifluoroacetimidate 4
(entries 5 and 6) with TMSOTf as an activator gave a good yield
although the stereoselectivity was modest. The use of glycosyl
phosphite (entries 7 and 8) with boron trifluoride or TMSOTf gave
a poor yield and low selectivity. These donors gave glycal 7 as the
b-
Entry Donor Lewis acid
(equiv)
Temp
Time Yield
(h) (%)
a
/
b
7 (%) 2 (%)a
a
1b
2
3
4
5
6
7
8
3
3
3
3
4
4
5
5
a
a
b
b
a
b
a
a
BF3$OEt2 (6.0)
ꢁ20 ꢀC
1.5 72
1.5 16
5:1
d
d
79
44
a
a
,
Cp2Hf(OTf)2 (2.2) ꢁ20 ꢀC
3.5:1 90
2.5:1 73
d
BF3$OEt2 (6.0)
ꢁ20 ꢀC to rt 10
41
d
4
b
TMSOTf (0.1)
TMSOTf (0.1)
TMSOTf (0.1)
TMSOTf (0.1)
BF3$OEt2 (1.0)
ꢁ20 ꢀC to rt 10
35c 75
ꢁ78 ꢀC
ꢁ78 ꢀC
ꢁ20 ꢀC
ꢁ20 ꢀC
2.0 48
2.0 61
2.5 35
2.0 30
2.4:1 52
2.6:1 38
3.8:1 61
42
27
50
d
2.1:1
d
major product. Glycosyl fluoride 3
as the activator provided the best yield and
reaction of glycosyl fluoride 3 in the presence of boron trifluoride
was the most effective for this reaction.
a
(entry 1) with boron trifluoride
a
a-selectivity. Thus, the
The yield was based on the donor.
See Ref. 7.
Twenty four percent of the donor was recovered.
b
c
a
Scheme 2. Glycosylation of the 4,5-diol acceptor.
All donors produced the
a
-glycoside as the main product, but
chloroacetimidate 9,15 branched trisaccharide 13 was also obtained
the stereoselectivity was not influenced by the type of leaving
group. Our results are consistent with the results reported by
Yoshizaki et al. that glycosylation with a 4,5-O-isopropylidinene-
in good yield (91%) (entry 4). The effect of the participating group
(Ac) at the C-2 position meant that only
a-isomer, which was
identified by the 1JHꢁ1
value of the Man residue (175 Hz), was
III;Cꢁ1III
protected Kdo fluoride donor has a high
2.2. Synthesis of 4,5-branched trisaccharides
Glycosylation of Kdo acceptor with
a
-selectivity.11
isolated. In contrast, for the heptose derivative, mannosylation
proceeded smoothly at 0 ꢀC with 0.04 equiv TMSOTf, and no
orthoester was detected. These results suggest that mannosyl do-
nor 9 was more active than heptosyl donor 8. Glycosylation of Kdo
6a
L-glycero-
D-man-
dimer 6a
with GalN3 trichloroacetimidate 1016 was accomplished
noheptosyl, mannosyl, and 2-azido-2-deoxy-galactosyl imidates
to give GalN3 containing branched trisaccharide 14 as a single
8e10 was examined (Scheme 3), and the results are presented in
isomer in moderate yield (56%) (entry 5). The coupling constant

R. Yi et al. / Tetrahedron 70 (2014) 3675e3682
3677
Scheme 3. Syntheses of 4,5-branched trisaccharides 11e14.
Table 2
Glycosylation of Kdo acceptor 6
azido-2-deoxy-galactosyl imidates 8e10
a
with
L
-glycero-
D
-mannoheptosyl, mannosyl, and 2-
Table 3
1H and 13C NMR spectrum data for compounds 11, 13, and 14
Entry Donor
Temp (ꢀC) TMSOTf Time Product (%) 12 (%)
6a (%)
11a
13a
14a
(equiv) (h)
dH (J in Hz)
dC
dH (J in Hz)
dC
dH (J in Hz)
dC
1
2
3
4
5
8(
8(
8(
9(
a
a
a
a
)
)
)
)
0
0.04
0.04
0.06
0.04
0.04
4
2
2
2
2
11 (10)
11 (28)
11 (87)
13 (91)
14 (56)
35
28
3
44
19
9
KdoI
rt
rt
0
1
2
167.4
98.7
167.3
98.7
167.1
98.2
d
d
3a 2.05 (12.6, 12.0) 34.4 2.23 (12.6, 12.2) 25.1 2.11 (12.6, 12.4) 34.4
3b 2.27 (12.6, 4.4) 2.28 (12.6, 4.8) 2.27 (12.6, 4.6)
67.6 4.73 67.5 4.79
10 (
a
/b
¼1:3)
0
d
40
4
4.65
67.7
(12.0, 4.4, 2.0)
3.73 (2.0, 1.8)
4.12 (1.8, 10.0)
5.69
(12.2, 4.8, 2.2)
72.3 3.78 (2.2, 1.6)
70.5 4.11 (1.6, 9.4)
69.2 5.46
(12.4, 4.6, 2.0)
72.5 3.83 (2.0, n.d.)
70.5 4.14 (n.d., 9.6)
68.9 5.70
5
6
7
72.02
70.4
69.4
(10.0, 3.6, 2.6)
(9.4, 3.8, 2.4)
(9.6, 3.0, 2.6)
8a 4.69 (3.6, 12.6)
8b 4.88 (2.6, 12.6)
62.4 4.63 (3.8, 12.6)
4.82 (2.4, 12.6)
62.3 4.64 (3.0, 12.0)
5.00 (2.6, 12.0)
62.2
KdoII
1
2
169.2
97.0
31.9 1.85 (15.4, 2.2)
2.95 (15.4, 3.6)
70.0 4.52
168.7
96.7
24.6 1.92 (15.4, 2.2)
3.01 (15.6, 3.6)
69.6 4.52
169.0
96.6
31.9
3a 2.12 (15.4, 2.2)
3b 2.95 (15.4, 3.6)
4
4.52
69.9
(2.2, 3.6, 8.0)
4.37 (8.0, 2.0)
4.28 (2.0, 7.4)
5.65
(2.2, 3.6, 7.8)
74.0 4.35 (7.8, 1.8)
70.4 4.18 (1.8, 7.2)
70.7 5.67
(2.2, 3.6, 7.8)
72.2 4.36 (7.8, 1.6)
70.6 4.21 (1.6, 7.6)
70.8 5.67
5
6
7
72.15
70.4
70.7
(7.4, 5.0, 2.4)
8a 4.60 (5.0, 12.6)
8b 5.28 (2.4, 12.6)
(7.2, 5.2, 2.4)
62.5 4.63 (5.2, 12.6)
5.30 (2.4, 12.6)
(7.6, 4.2, 2.5)
62.2 4.62 (4.2, 12.6)
5.33 (2.5, 12.6)
62.0
Hep
Man
GalN3
1
2
3
4
5
5.04 (2.0)
5.24 (2.0, 3.2)
5.51 (3.2, 10.2)
5.32 (10.2, 10.0) 65.2 5.34 (3.4, 10.0)
4.22 (10.0, 8.0) 69.2 4.32
(10.0, 2.0, 3.2)
99.0 4.82 (2.2)
70.3 5.42 (3.4, 11.0)
68.7 5.40 (11.0, 3.4)
98.5 5.05 (3.4)
69.2 3.74 (3.4, 11.0)
69.8 5.32 (11.0, 3.2)
66.0 5.48 (3.2, 0.8)
68.7 4.54
97.9
58.2
68.8
67.1
66.6
Fig. 1. Partial HMBC spectrum of compound 11 in CDCl3 at 25 ꢀC.
between H-1III and H-2III (JH-1,H-2¼3.4 Hz) of the GalN3 residue in-
(0.8, 5.5, 9.0)
61.8 4.08 (5.5, 10.8)
dicated that an a
-glycosidic linkage was formed.14 The position of
6a 5.37
(8.0, 2.4, 4.0)
6b
7a 4.23 (2.4, 12.0)
7b 4.26 (4.0, 12.0)
67.4 4.09 (2.0, 12.2)
60.4
azide group meant this glycosylation exploited the anomeric effect
to give the -isomer. In addition, the presence of acetyl groups at
the 3- and 4-position was also favorable for
-isomer formation.17
Thin layer chromatography (TLC) also suggested that for the
a
4.39 (3.2, 12.2)
63.7
4.15 (9.0, 10.8)
a
a
Data were acquired in CDCl3 at 25 ꢀC. Only the data for the skeletal carbon atoms
are presented, and those for other carbon atoms are listed in Experimental section.
GalN3 donor, the
(Table 3).
b-isomer is more active than the a-isomer

3678
R. Yi et al. / Tetrahedron 70 (2014) 3675e3682
Next, the transformation of the azide group to the acetamide
were recorded at 25 ꢀC on a Bruker Avance II 600 MHz NMR
spectrometer. 1H NMR spectra were referenced to internal stan-
dards of the residual protonated solvent peaks: dH 7.24 ppm for
solutions in CDCl3, and dH 4.75 ppm for solutions in D2O. The 13C
NMR spectra were recorded at 150 MHz and were referenced to the
residual CDCl3 peak (77.0 ppm). Multiplicities are reported as sin-
glet (s), broad singlet (br s), doublet (d), double doublets (dd),
triplet (t), or multiplet (m). Spectra were assigned using COSY,
group in trisaccharide 14 was carried out. The azide group could not
be converted directly to the acetamide group by thioacetic acid
(data not shown).18 Hence, a stepwise conversion was used
(Scheme 4). First, the azide group of GalN3 14 was reduced to the
amine group under Staudinger conditions,19 and was then acety-
lated with anhydrous acetic acid in the presence of N,N-dimethy-
laminopyridine (DMAP). Finally, GalNAc trisaccharide 15 was
obtained in moderate yield (64%).
HMQC, and HMBC experiments. All NMR chemical shifts (d) were
Scheme 4. Conditions: (a) (i) Ph3P, THF/H2O¼19:1, rt, 16 h; (ii) Ac2O, DMAP, pyridine, rt, 17 h, two steps: 64%; (b) 80% TFA, CH2Cl2, rt, then 0.1 M NaOH, MeOH, two steps: GalNAc 16
(quant), Hep 17 (87%), Man 18 (93%). DMAP: N,N-dimethylaminopyridine; TFA: trifluoroacetic acid.
Finally, acid hydrolysis of the isopropylidene group of the Kdo
trisaccharide (11, 13, and 15) with aqueous trifluoroacetic acid and
subsequent hydrolysis in 0.1 M sodium hydroxide to remove the
ester groups afforded fully deprotected 4,5-branched Kdo tri-
saccharides 16e18 as disodium salts in good yield (GalNAc 16:
quantitative; Hep 17: 87%; Man 18: 93%).
recorded in parts per million (ppm), and coupling constants (J)
were reported in hertz (Hz). Mass spectrometry (MS) was per-
formed by positive- and negative-mode electrospray ionization on
a Waters LCT Premier spectrometer. For high-precision measure-
ments, the spectra were obtained by scanning the voltage over
a narrow mass range at a resolution of 10,000. MALDI-TOF spectra
were recorded on a Bruker Daltonics instrument, using 3,5-
dihydroxybenzoic acid as the matrix. Elemental analysis was car-
ried out on a Vario ELCUBE and a Vario EL III from Elementar. In-
2.3. Conclusion
frared spectra were determined on
a
JASCO FT/IR-4100
A new synthetic strategy using Kdo (2-4)Kdo 6a as an acceptor
spectrometer. Analytical TLC was performed on Merck silica gel
60 F254 glass plates. The TLC plates were visualized with UV light
and by staining with Hannessian solution (ceric sulfate and am-
monium molybdate in aqueous sulfuric acid), and then heating at
200 ꢀC for 3 min. Column chromatography was performed on silica
gel 60 (flash column: 0.040e0.063 mm; open column:
0.063e0.200 mm).
was developed for the synthesis of 4,5-branched Kdo tri-
saccharides. Glycosylation at the 4-OH position of the Kdo acceptor
followed by a second glycosylation at 5-OH position produced the
heptosyl Kdo dimer, Hep(
the first synthesis of the 4,5-branched partial inner-core tri-
saccharides Man( 1-5)[Kdo( 2-4)]Kdo (13) from Francisella tular-
ensis20 and GalN3(
1-5)[Kdo( 2-4)]Kdo (14) from Pseudomonas
cichorii21 in good yield and high
-selectivity. The most suitable
reaction conditions for the synthesis of Kdo(2-4)Kdo 6 were an
a1-5)[Kdo(a2-4)]Kdo. We also achieved
a
a
a
a
a
a
-
3.2. Methyl (7,8-di-O-benzoyl-4,5-O-isopropylidene-3-deoxy-
fluoride donor with boron trifluoride as the activator. This new
route should be more effective for the synthesis of the inner-core
oligosaccharide of LPS/LOS than Paulsen’s method. Ultimately, the
fully deprotected 4,5-branched trisaccharides 16e18 will be used
for immunological assessments.
D
-manno-2-octulopyranosyl N-phenyl trifluoroacetimidate)
onate (4)
To a solution of methyl (7,8-di-O-benzoyl-4,5-O-isopropyli
dene-3-deoxy- -manno-2-octulopyranoside)onate (250 mg,
0.5 mmol) in dry dichloromethane (5 mL) under argon was added
N-phenyl trifluoroacetimidoyl chloride22 (716
L, 5.0 mmol). Then
D
1
3. Experiment section
3.1. General procedures
m
potassium carbonate (113 mg, 5.0 mmol) was added into the re-
action mixture. After stirring for 1 week, the mixture was filtered
through CeliteÒ. The solution was concentrated and purified by
silica gel column chromatography (ethyl acetate/toluene¼1:5) to
Optical rotation was measured with a Horiba SEPA500 polar-
imeter in CHCl3, and melting point (uncorrected) was measured
with a Yanagimoto micro melting point apparatus. All NMR spectra
give a mixture of anomers in quantitative yield (343 mg,
a/
25
b
¼3:2).
a
-isomer: [
a
]
þ75.6 (c 1.0, CHCl3). 1H NMR (600 MHz,
D

R. Yi et al. / Tetrahedron 70 (2014) 3675e3682
3679
CDCl3):
d
1.24 (s, 3H, Me), 1.50 (s, 3H, Me), 2.33 (1H, J3a,3e¼15.6 Hz,
1252, 1213, 973 cmꢁ1. ESI-HRMS calcd for C40H41O12P: 767.2233
25
J3a,4¼3.4 Hz, H-3a), 2.78 (dd, 1H, J3a,3e¼15.6 Hz, J3e,4¼4.0 Hz, H-
3e), 3.78 (s, 3H, OMe), 4.37 (dd, 1H, J5,6¼2.0 Hz, J6,7¼8.6 Hz, H-6),
4.41 (dd, 1H, J4,5¼7.6 Hz, J5,6¼2.0 Hz, H-5), 4.62 (ddd, 1H,
J3a,4¼3.4 Hz, J3e,4¼4.0 Hz, J4,5¼7.6 Hz, H-4), 4.72 (dd, 1H,
J7,8a¼4.0 Hz, J8a,8b¼12.4 Hz, H-8a), 5.00 (dd, 1H, J7,8b¼2.4 Hz,
J8a,8b¼12.4 Hz, H-8b), 5.75 (ddd, 1H, J6,7¼8.6 Hz, J7,8a¼4.0 Hz,
J7,8b¼2.4 Hz, H-7), 6.74e6.75 (m, 2H, NPheAr), 7.05 (m, 1H,
NPheAr), 7.24e7.25 (m, 2H, NPheAr), 7.37e7.44 (m, 4H, Ar),
7.51e7.57 (m, 2H, Ar), 7.98e8.03 (m, 4H, Ar). 13C NMR (150 MHz,
[MþNa]þ. Found 767.2222.
b
-isomer: [
a]
þ23.4 (c 1.0, CHCl3). 1H
D
NMR (600 MHz, CDCl3):
d 1.21, 1.42 (s, 2H, CH3), 2.40 (dd, 1H,
J3a,3b¼15.2 Hz, J3a,4¼3.0 Hz, H-3a), 2.94 (dd, 1H, J3a,3b¼15.2 Hz,
J3b,4¼5.6 Hz, H-3e), 3.73 (s, 3H, OMe), 4.35 (dd, 1H, J4,5¼7.6 Hz,
J5,6¼2.0 Hz, H-5), 4.52 (ddd, IH, J3a,4¼3.0 Hz, J3b,4¼5.6 Hz,
J4,5¼7.6 Hz, H-4), 4.65 (dd, 1H, J5,6¼2.0 Hz, J6,7¼7.4 Hz, H-6), 4.66
(dd, 1H, J7,8a¼7.0 Hz, J8a,8b¼12.4 Hz, H-8a), 4.95e5.02 (m, 4H,
OCH2), 5.02 (dd, 1H, J7,8b¼2.4 Hz, J8a,8b¼12.4 Hz, H-8b), 5.78 (ddd,
1H, J6,7¼7.4 Hz, J7,8a¼7.0 Hz, J7,8b¼2.4 Hz, H-7), 7.25e7.53 (m, 16H,
CDCl3):
d
24.8, 25.6 (CH3), 33.0 (C-3), 52.8 (OCH3), 62.6 (C-8), 69.5
Ar), 7.98e8.03 (m, 4H, Ar). 13C NMR (150 MHz, CDCl3):
d 24.6, 25.4
(C-4), 70.1 (C-7), 70.2 (C-6), 70.8 (C-5), 99.0 (C-2), 110.1 (Cisop),
116.5 (CF3), 119.1 (NPheAr), 124.3 (NPheAr), 128.4, 128.47, 128.7,
129.4, 129.6, 129.7, 129.8, 133.1, 133.3 (14C, NPheAr and Ar), 143.15
(C]N), 165.08, 166.15 (C]O), 168.06 (C-1). IR (neat): 1736, 1727,
(CH3), 32.2 (C-3), 53.0 (OCH3), 63.5 (C-8), 69.5 (C-4), 69.56, 69.6
(2C, OCH2), 70.3 (C-7), 71.3 (C-5), 72.1 (C-6), 100.0 (C-2), 109.8
(Cisop), 128.1, 128.2, 128.3, 128.36, 128.42, 128.46, 128.48, 128.50,
129.7, 129.75, 129.79, 130.1, 132.8, 133.1, 135.6 (Ar), 165.3, 166.2
(C]O), 167.2 (C-1). IR(neat): 1748, 1717, 1253, 1213, 954 cmꢁ1. ESI-
HRMS calcd for C40H41O12P: 767.2233 [MþNa]þ. Found 767.2223.
1229, 1215, 1202 cmꢁ1
. ESI-HRMS calcd for C34H32F3NO10:
694.1876 [MþNa]þ. Found 694.1873.
b
-isomer: [
d 1.29 (s, 3H, Me), 1.54 (s, 3H,
a
]
þ6.6 (c 1.0,
25
D
CHCl3). 1H NMR (600 MHz, CDCl3):
Me), 2.34 (dd, 1H, J3a,3b¼16.2 Hz, J3a,4¼3.4 Hz, H-3a), 2.78 (dd, 1H,
J3a,3b¼16.2 Hz, J3e,4¼3.0 Hz, H-3b), 3.66 (s, 3H, OMe), 4.26 (dd, 1H,
J5,6¼1.8 Hz, J6,7¼8.0 Hz, H-6), 4.44 (dd, 1H, J4,5¼8.2 Hz, J5,6¼1.8 Hz,
H-5), 4.68 (ddd, 1H, J3a,4¼3.4 Hz, J3b,4¼3.0 Hz, J4,5¼8.2 Hz, H-4),
4.70 (dd, 1H, J7,8a¼5.2 Hz, J8a,8b¼12.4 Hz, H-8a), 4.97 (dd, 1H,
J7,8b¼2.4 Hz, J8a,8b¼12.4 Hz, H-8b), 5.68e5.71 (ddd, 1H,
J6,7¼8.6 Hz, J7,8a¼5.2 Hz, J7,8b¼2.4 Hz, H-7), 6.74e6.75 (m, 2H,
NPheAr), 7.09 (m, 1H, NPheAr), 7.27e7.28 (m, 2H, NPheAr),
7.39e7.44 (m, 4H, Ar), 7.51e7.57 (m, 2H, Ar), 7.98e8.03 (m, 4H,
3.4. 2,3,4,6,7-Penta-O-acetyl-
anosyl-(1-5)-[methyl O-[methyl (7,8-di-O-benzoyl-4,5-O-iso-
propylidene-3-deoxy- -manno-2-octulopyranosyl)onate]]-
(2-4)-(allyl 7,8-di-O-benzoyl-3-deoxy-a-D-manno-2-
octulopyranosyl)onate (11)
L-glycero-a-D-manno-heptopyr-
a-D
A mixture of methyl O-[methyl (7,8-di-O-benzoyl-4,5-O-iso-
propylidene-3-deoxy- -manno-2-octulopyranosyl)onate]-(2-4)-
7,8-di-O-benzoyl-3-deoxy- -manno-2-octulopyranosyl)
(32.0 mg, 32.6 mol), 2,3,4,6,7-penta-O-acetyl- -glycero-
(55.0 mg,
mol), and MS-AW 300 (40 mg) was suspended in
dichloromethane (1.0 mL). The reaction mixture was stirred for 1 h
under argon, and then 0.01 M TMSOTf (196.0 L, 1.96 mol) in
a-D
(allyl
a-D
Ar). 13C NMR (150 MHz, CDCl3):
d
25.6, 25.8 (CH3), 29.7 (C-3), 52.8
onate 6
a
m
L
(OCH3), 62.9 (C-8), 69.2 (C-4), 70.5 (C-7), 70.9 (C-5), 71.5 (C-6),
99.3 (C-2), 110.0 (Cisop), 114.6 (CF3), 119.3 (NPheAr), 124.33
(NPheAr), 128.36, 128.45, 128.56, 128.79, 129.64, 129.72, 129.75,
129.83, 129.98, 133.99, 133.24 (14C, NPheCmeta and Ar), 143.21
(C]N), 165.24, 166.09 (C]O), 167.91 (C-1). IR(neat): 1736, 1725,
a-
D-manno-heptopyranosyl trichloroacetimidate
8
98.7
m
m
m
dichloromethane was added dropwise to the reaction mixture.
After stirring for 2 h, the reaction mixture was neutralized by the
addition of a few drops of triethylamine and aqueous saturated
sodium hydrogen carbonate. The reaction mixture was diluted
with dichloromethane and was filtered through CeliteÒ. The fil-
trate was extracted twice with dichloromethane. The combined
organic phase was dried over anhydrous sodium sulfate, filtered,
and concentrated. The residue was purified by BioRad S-X3 (tol-
1230, 1214, 1205 cmꢁ1
. ESI-HRMS calcd for C34H32F3NO10:
694.1876 [MþNa]þ. Found 694.1855.
3.3. Methyl (dibenzyl-7,8-di-O-benzoyl-4,5-O-isopropylidene-
3-deoxy-D-manno-2-octulopyranosyl phosphite)onate (5)
To
a
solution of methyl (7,8-di-O-benzoyl-4,5-O-iso-
-manno-2-octulopyranoside)onate
propylidene-3-deoxy-
D
1
uene/ethyl acetate¼1:1) to give compound 11 (39 mg, 87%) as
25
(200 mg, 0.40 mmol) in dry dichloromethane (13.0 mL) under
argon was added 1H-tetrazole (112 mg, 1.6 mmol). Then the re-
action mixture was cooled to 0 ꢀC and treated with dibenzyl N,N-
colorless syrup. Mp 88.2 ꢀC, [
(600 MHz, CDCl3):
a
]
D
þ19.7 (c 1.5, CHCl3). 1H NMR
d 1.20 (s, 3H, Me), 1.38 (s, 3H, Me), 1.93, 2.02,
2.03, 2.14 (s, 3Hꢂ5), Ac), 3.43 (s, 3H, OMeI), 3.47 (s, 3H, OMeII),
3.93 (dd, 1H, J¼1.6, 1.6, 4.8, 13.0 Hz, OCH2e), 3.97 (dd, 1H, J¼1.4,
1.6, 5.4, 13.0 Hz, OCH2e), 4.93 (dd, 1H, J¼1.4, 1.6, 3.0, 10.6 Hz, ]
CH2), 5.01 (dd, 1H, J¼1.6, 1.6, 3.2, 17.2 Hz, ]CH2), 5.62e5.68 (m,1H,
eCH]), 7.37e7.45 (m, 8H, ArI, ArII), 7.51e7.56 (m, 4H, ArI, ArII),
diisopropylphosphoramidite (DDP, 320 mL/0.96 mmol). After stir-
ring for 3 h, the solution was quenched with triethylamine (Et3N)
and concentrated. The residue was purified by silica gel column
chromatography (ethyl acetate/hexane¼2:3 containing with 1%
Et3N) to give a mixture of anomers in 56% yield (167 mg,
a
/
7.93e8.01 (m, 8H, ArI, ArII). 13C NMR (150 MHz, CDCl3):
d 20.69,
25
b
¼23:1).
a-isomer: [a]
þ33.8 (c 1.1, CHCl3). 1H NMR (600 MHz,
20.74, 20.8 and 21.1 (AceCH3), 24.7 and 25.1 (IsopeMe), 52.25
(OMeI), 52.28 (OMeII), 64.7 (OCH2e), 109.7 (Cisop), 116.2 (]CH2),
128.3, 128.4, 128.5, 129.3, 129.6, 129.85, 129.90, 130.2, 132.8, 133.1
(ArI and ArII), 133.4 (eCH]), 165.1, 165.2, 165.8, 167.4 (Bz: C]O),
169.6, 169.7, 169.8, 170.4 and 170.7 (Ac: C]O). IR (neat): 1745,
D
CDCl3):
d
1.20 and 1.43 (s, 2H, CH3), 2.06 (dd, 1H, J3a,3b¼15.0 Hz,
J3a,4¼3.4 Hz, H-3a), 2.82 (dd, 1H, J3a,3b¼15.0 Hz, J3b,4¼5.2 Hz, H-3e),
3.70 (s, 3H, OMe), 4.25 (dd, 1H, J4,5¼7.0 Hz, J5,6¼2.0 Hz, H-5), 4.34
(dd, 1H, J5,6¼2.0 Hz, J6,7¼7.4 Hz, H-6), 4.47 (ddd, IH, J3a,4¼3.4 Hz,
J3e,4¼5.2 Hz, J4,5¼7.0 Hz, H-4), 4.66 (dd, 1H, J7,8a¼6.0 Hz,
J8a,8b¼12.4 Hz, H-8a), 4.77 (dd, 1H, J¼12.4 and 7.8 Hz, OCH2Ph),
4.81 (d, 2H, J¼7.8 Hz, OCH2Ph), 4.83 (dd, 1H, J¼12.2 and 8.4 Hz,
OCH2Ph), 5.00 (dd, 1H, J7,8b¼2.4 Hz, J8a,8b¼12.4 Hz, H-8b), 5.74
(ddd, 1H, J6,7¼7.4 Hz, J7,8a¼6.0 Hz, J7,8b¼2.4 Hz, H-7), 7.18e7.54 (m,
16H, Ar), 7.97e8.03 (m, 4H, Ar). 13C NMR (150 MHz, CDCl3):
1725, 1278, 1248, 1218 cmꢁ1. Anal. Calcd for C69H76O30: C, 59.82; H,
25
5.53. Found C, 59.65; H, 5.67. Orthoester 12: mp 99.0 ꢀC. [
a]
þ7.5
D
(c 1.0, CHCl3), 1H NMR (600 MHz, CDCl3):
d 1.21 (s, 3H, Me), 1.40 (s,
3H, Me), 1.65 (s, 3H, ester-Me), 1.91 (dd, 1H, J3a,3b¼15.4 Hz,
J3a,4¼2.2 Hz, H-3aII), 1.97, 2.03, 2.04, 2.07 (s, 3Hꢂ4, Ac), 2.31 (dd,
1H, J3a,3b¼12.6 Hz, J3a,4¼12.4 Hz, H-3aI), 2.47 (dd, 1H,
J3a,3b¼12.6 Hz, J3b,4¼4.0 Hz, H-3bI), 2.86 (dd, 1H, J3a,3b¼15.4 Hz,
J3b,4¼3.6 Hz, H-3bII), 3.38 (ddd, 1H, J4,5¼9.6 Hz, J5,6¼2.0 Hz, H-5III),
3.43 (s, 3H, OMeI), 3.81 (s, 3H, OMeII), 3.86 (dd, 1H, J¼1.6, 1.6, 3.4,
13.4 Hz, OCH2e), 3.97 (dd, 1H, J¼1.6, 1.6, 3.2, 13.4 Hz, OCH2e), 4.05
(dd, 1H, J5,6¼nd, J6,7¼8.6 Hz, H-6I), 4.09 (dd, 1H, J6,7a¼7.8 Hz,
J7a,7b¼11.6 Hz, H-7aIII), 4.11 (br s, 1H, J4,5¼2.4 Hz, J5,6¼nd, H-5I),
d
25.04, 26.01 (CH3), 33.69 (C-3), 52.74 (OCH3), 63.28 (C-8), 64.2 (d,
2JC,P¼6.3 Hz, OCH2), 64.6 (d, 2JC,P¼8.8 Hz, OCH2), 69.82 (C-4), 70.56
(C-7), 70.66 (C-6), 71.38 (C-5), 97.29, 97.33 (C-2), 109.73 (Cisop),
127.62, 127.69, 127.72, 128.06, 128.30, 128.37, 128.39, 128.74,
129.75, 129.91, 130.10, 132.87, 133.13, 137.91, 137.95, 137.98 (Ar),
165.30, 166.21 (C]O), 168.66 (C-1). IR(neat): 1749, 1713, 1282,

3680
R. Yi et al. / Tetrahedron 70 (2014) 3675e3682
4.15 (dd, 1H, J6,7b¼4.8 Hz, J7a 7b
,
¼11.6 Hz, H-7bIII), 4.21 (dd, 1H,
3.6. 3,4,6-Tri-O-acetyl-2-azido-2-deoxy-
(1-5)-[methyl O-[methyl (7,8-di-O-benzoyl-4,5-O-iso-
propylidene-3-deoxy- -manno-2-octulopyranosyl)onate]]-
(2-4)-(allyl 7,8-di-O-benzoyl-3-deoxy-a-D-manno-2-
octulopyranosyl)onate (14)
a-D-galactopyranosyl-
J5,6¼1.8 Hz, J6,7¼7.0 Hz, H-6II), 4.31 (dd, 1H, J4,5¼7.6 Hz, J5,6¼1.8 Hz,
H-5II), 4.33 (ddd, 1H, J3a,4¼12.4 Hz, J3e,4¼4.0 Hz, J4,5¼2.4 Hz, H-4I),
4.47 (ddd, 1H, J3a,4¼2.2 Hz, J3e,4¼3.6 Hz, J4,5¼7.6 Hz, H-4II), 4.50
(dd, 1H, J1,2¼2.2 Hz, J2,3¼3.8 Hz, H-2III), 4.60 (ddd, 1H, J7,8a¼4.6 Hz,
J8a,8b¼12.4 Hz, H-8aII), 4.64 (dd, 1H, J7,8a¼3.4 Hz, J8a,8b¼12.6 Hz, H-
8aI), 4.65 (d, 1H, J1,2¼2.2 Hz, H-1III), 4.94 (dd, 1H, J¼1.4, 1.4, 3.0,
10.6 Hz, ]CH2), 5.00 (dd, 1H, J7,8b¼2.4 Hz, J8a,8b¼12.6 Hz, H-8bI),
5.02 (dd, 1H, J2,3¼3.8 Hz, J3,4¼10.0 Hz, H-3III), 5.05 (dd, 1H, J¼1.6,
1.6, 3.4, 17.2 Hz, ]CH2), 5.11 (dd, 1H, J3,4¼10.0 Hz, J4,5¼9.6 Hz, H-
4III), 5.14 (ddd, 1H, J5,6¼2.0 Hz, J6,7a¼7.8 Hz, J6,7b¼4.8 Hz, H-6III),
5.24 (dd, 1H, J7,8b¼2.4 Hz, J8a,8b¼12.4 Hz, H-8bII), 5.38 (ddd, 1H,
J6,7¼8.6 Hz, J7,8a¼3.4 Hz, J7,8b¼2.4 Hz, H-7I), 5.59e5.64 (m, 1H,
eCH]), 5.65 (ddd, 1H, J6,7¼7.0 Hz, J7,8a¼4.6 Hz, J7,8b¼2.4 Hz, H-7II),
7.39e7.47 (m, 8H, ArI, ArII), 7.54e7.55 (m, 4H, ArI, ArII), 7.95e8.01
a-D
A reaction mixture of methyl O-[methyl (7,8-di-O-benzoyl-4,5-O-
isopropylidene-3-deoxy- -manno-2-octulopyranosyl)onate]-(2-
4)-(allyl 7,8-di-O-benzoyl-3-deoxy- -manno-2-octulopyranosyl)
onate 6 (50.0 mg, 51.0 mol), 3,4,6-tri-O-acetyl-2-azido-2-deoxy-
-galactopyranosyl trichloroacetimidate 10 (72.6 mg, 152.6 mol),
and MS-AW 300 (57.8 mg) in dichloromethane (1.4 mL) was stirred
for 1 h under argon and cooled to 0 ꢀC. Then 0.01 M TMSOTf (200
L,
2.00 mol) in dichloromethane was added dropwise to the reaction
a-D
a-D
a
m
D
m
m
m
mixture and stirred for 4 h. The solution was neutralized by the
addition of triethylamine and saturated NaHCO3 and diluted with
dichloromethane. The reaction mixture was filtered through CeliteÒ,
and the filtrate was extracted with dichloromethane. The organic
phase was dried over Na2SO4, filtered, and concentrated. Purifica-
tion of the residue by BioRad S-X3 (toluene/ethyl acetate¼1:1) ob-
(m, 8H, ArI, ArII). 13C NMR (150 MHz, CDCl3):
d 20.6, 20.6, 20.7
(AceCH3), 24.7 and 25.3 (IsopeMe), 26.3 (ester-Me), 32.6 (C-3II),
34.3 (C-3I), 52.2 (OMeI), 52.5 (OMeII), 62.2 (C-8II), 62.4 (C-8I), 62.5
(C-7III), 64.2 (OCH2e), 64.6 (C-4III), 66.8 (C-6III), 67.5 (C-5I), 69.2 (C-
4I), 69.8 (C-4II), 70.2 (C-6II), 70.3 (C-3III), 70.4 (C-7I), 70.96 (C-7II),
70.96 (C-6I), 71.1 (C-5III), 72.1 (C-5II), 76.2 (C-2II), 97.2 (C-1III), 98.5
(C-2I), 98.8 (C-2II), 109.7 (Cisop), 115.6 (]CH2), 124.8 (ester-C),
128.40, 128.43, 128.5, 129.5, 129.7, 129.8, 129.9, 130.0, 130.4, 133.0,
133.07, 133.14 (ArI and ArII), 133.7 (eCH]), 165.1, 165.3, 165.9,
166.2 (Bz: C]O), 167.5 (C-1I), 169.4 (C-1II), 170.1, 170.17, 170.24 and
tained compound 14 (38 mg, 58%) as colorless powder. Mp 96.0 ꢀC,
25
[a]
þ51.0 (c 1.0, CHCl3). 1H NMR (600 MHz, CDCl3):
d 1.21 (s, 3H,
D
Me), 1.39 (s, 3H, Me), 1.96, 2.06, 2.11 (s, 3Hꢂ3, Ac), 3.32 (s, 3H, OMeI),
3.59 (s, 3H, OMeII), 3.95 (dd,1H, J¼5.4 and 13.0 Hz, OCH2e), 3.97 (dd,
1H, J¼5.0 and 13.0 Hz, OCH2e), 4.91 (dd, 1H, J¼10.0 and 1.4 Hz, ]
CH2), 4.99 (dd, 1H, J¼10.0 and <0.2 Hz, ]CH2), 5.63e5.67 (m,1H,
eCH]), 7.36e7.39 (m, 2H, ArI, ArII), 7.42e7.45 (m, 3H, ArI, ArII),
7.51e7.58 (m, 4H, ArI, ArII), 7.94e8.03 (m, 8H, ArI, ArII). 13C NMR
170.6 (Ac: C]O). IR(neat): 1746, 1724, 1279, 1248, 1219 cmꢁ1
.
ESI-HRMS calcd for
1407.4302.
C
69H76O30
:
1407.4319 [MþNa]þ. Found
(150 MHz, CDCl3): d 20.6 and 20.7 (AceCH3), 24.6 and 25.1 (Me), 52.1
3.5. 2,3,4,6-Tetra-O-acetyl-
[methyl O-[methyl (7,8-di-O-benzoyl-4,5-O-isopropylidene-3-
deoxy- -manno-2-octulopyranosyl)onate]]-(2-4)-(allyl 7,8-
di-O-benzoyl-3-deoxy-a-D-manno-2-octulopyranosyl)onate
(13)
a
-
D
-mannopyranosyl-(1-5)-
(OMeII), 52.2 (OMeI), 64.8 (OCH2e), 109.8 (Cisop), 116.4 (]CH2),
128.4, 128.47, 128.52, 129.5, 129.65, 129.72, 129.8, 130.2, 132.9, 133.1
and 133.5 (ArI and ArII), 133.15 (eCH]), 165.2, 165.8, 166.2 (Bz: C]
O),169.7,170.1 and 170.2 (Ac: C]O). IR (neat): 2112,1748,1723,1278,
1251, 1218 cmꢁ1. ESI-HRMS calcd for C64H69N3O26: 1318.4067
[MþNa]þ. Found 1318.4072.
a-D
A reaction mixture of 2,3,4,6-tetra-O-acetyl-
anosyl trichloroacetimidate 9 (75.2 mg, 152.6 mol), methyl O-
[methyl (7,8-di-O-benzoyl-4,5-O-isopropylidene-3-deoxy-
manno-2-octulopyranosyl)onate]-(2-4)-(allyl 7,8-di-O-benzoyl-3-
deoxy- -manno-2-octulopyranosyl)onate (50.0 mg,
51.0 mol), and MS-AW 300 (57.8 mg) was suspended in
a-D-mannopyr-
m
3.7. 3,4,6-Tri-O-acetyl-2-acetamido-2-deoxy-
anosyl-(1-5)-[methyl O-[methyl (7,8-di-O-benzoyl-4,5-O-iso-
propylidene-3-deoxy- -manno-2-octulopyranosyl)onate]]-
a-D-galactopyr-
a-D-
a-D
a
-D
6
a
(2-4)-(allyl 7,8-di-O-benzoyl-3-deoxy-a-D-manno-2-
octulopyranosyl)onate (15)
m
dichloromethane (1.4 mL). The reaction mixture was stirred for 1 h
under argon, and then cooled to 0 ꢀC. To the reaction mixture,
To a solution of 3,4,6-tri-O-acetyl-2-azido-2-deoxy-
actopyranosyl-(1-5)-[methyl O-[methyl(7,8-di-O-benzoyl-4,5-O-
isopropylidene-3-deoxy- -manno-2-octulopyranosyl)onate]]-(2-
4)-(allyl 7,8-di-O-benzoyl-3-deoxy- -manno-2-octulopyranosyl)
onate 14 (23.7 mg, 18.3 mol) dissolved in a mixed solvent (THF/
H2O¼19:1, 0.36 mL) was added triphenylphosphine (6.2 mg,
23.7 mol). After stirring for 16 h, the reaction mixture was diluted
a-D-gal-
0.01 M TMSOTf (200.0
mL, 2.00 mmol) in dichloromethane was
added dropwise. After stirring for 2 h, the reaction mixture was
neutralized by the addition of triethylamine and saturated sodium
hydrogen carbonate. The reaction solution was diluted with
dichloromethane and then filtered through CeliteÒ. The filtrate was
extracted twice with dichloromethane. The combined organic layer
was dried over Na2SO4, filtered, and concentrated. The residue was
a-D
a-D
m
m
with toluene and concentrated by evaporation. Without purifica-
purified by BioRad S-X3 (toluene/ethyl acetate¼1:1) to give com-
tion, the residue was directly acetylated with pyridine/Ac2O
(1:0.04, v/v,190.0 mL) in the presence of a catalytic amount of DMAP
25
pound 13 (60.9 mg, 91%) as colorless powder. Mp 85.5 ꢀC, [
a
]
D
þ37.5 (c 1.0, CHCl3). 1H NMR (600 MHz, CDCl3):
d
1.21 (s, 3H, Me),
over 18 h. After removing the solvent, the residue was purified by
TLC (CH2Cl2/EtOAc/hexane¼3:3:1) to give compound 15 (15.4 mg,
1.38 (s, 3H, Me), 2.00, 2.02, 2.05, 2.16 (s, 3Hꢂ4, Ac), 3.42 (s, 3H,
OMeI), 3.56 (s, 3H, OMeII), 3.92 (dd, 1H, J¼1.6, 1.6, 5.0, 13.0 Hz,
OCH2e), 3.97 (dd, 1H, J¼1.4, 1.4, 5.4, 13.0 Hz, OCH2e), 4.92 (dd, 1H,
J¼1.4, 1.6, 2.8, 10.6 Hz, ]CH2), 5.01 (dd, 1H, J¼1.4, 1.6, 3.2, 17.2 Hz, ]
CH2), 5.63e570 (m,1H, eCH]), 7.37e7.44 (m, 8H, ArI, ArII),
7.52e7.57 (m, 4H, ArI, ArII), 7.94e7.99 (m, 8H, ArI, ArII). 13C NMR
64%) as colorless powder. Mp 99.0 ꢀC, [
NMR (600 MHz, CDCl3): d 1.20 (s, 3H, Me), 1.37 (s, 3H, Me), 1.88 (dd,
a
]
25 þ62.1 (c 1.2, CHCl3). 1H
D
1H, J3a,3b¼15.6 Hz, J3a,4¼2.0 Hz, H-3aII), 1.97, 2.00, 2.14 (s, 3Hꢂ3, Ac),
2.02 (s, 3H, NHAc), 2.18 (dd, 1H, J3a,4¼11.8 Hz, J3a,3b¼13.0, H-3aI),
2.23 (dd, 1H, J3b,4¼5.6 Hz, J3a,3b¼13.0, H-3bI), 3.02 (dd, 1H,
J3a,3b¼15.6 Hz, J3b,4¼3.4 Hz, H-3bII), 3.35 (s, 3H, OMeI), 3.43 (s, 3H,
OMeII), 3.74 (brs, 1H, J4,5¼2.0 Hz, J5,6¼1.6 Hz, H-5I), 3.83 (dddd, 1H,
J¼1.4,1.6, 4.8 and 11.0 Hz, OCH2e), 3.90 (dddd,1H, J¼1.6, 1.6, 6.0 and
12.4 Hz, OCH2e), 4.06 (dd, 1H, J5,6a¼5.0 Hz, J6a,6b¼10.8 Hz, H-6aIII),
4.11 (dd, 1H, J5,6¼1.6 Hz, J6,7¼9.8 Hz, H-6I), 4.14 (dd,1H, J5,6b¼9.4 Hz,
J6a,6b¼10.8 Hz, H-6bIII), 4.19 (dd, 1H, J5,6¼1.6 Hz, J6,7¼8.0 Hz, H-6II),
4.36 (dd, 1H, J4,5¼7.8 Hz, J5,6¼1.6 Hz, H-5II), 4.53 (ddd, 1H,
(150 MHz, CDCl3): d 20.7, 20.76, 20.78 and 20.9 (AceCH3), 24.6 and
25.1 (Me), 52.2 (OMeI), 52.4 (OMeII), 64.8 (OCH2e), 109.8 (Cisop),
116.3 (]CH2), 128.36, 128.41, 128.46, 128.50, 129.0, 129.62, 129.64,
129.7, 129.8, 130.17 and 133.15 (ArI and ArII), 133.47 (eCH]), 164.8,
165.3, 165.8, and 166.2 (Bz: C]O), 169.56, 169.61, 169.8 and 170.8
(Ac: C]O). IR (neat): 1746, 1724, 1278, 1249, 1217 cmꢁ1. ESI-HRMS
calcd for C66H72O28: 1335.4108 [MþNa]þ. Found 1335.4097.

R. Yi et al. / Tetrahedron 70 (2014) 3675e3682
3681
J3a,4¼2.0 Hz, J3e,4¼3.4 Hz, J4,5¼7.8 Hz, H-4II), 4.53 (ddd, 1H,
isopropylidene-3-deoxy-
(2-4)-(allyl 7,8-di-O-benzoyl-3-deoxy-
anosyl)onate 11 (21 mg, 15.2 mol) in dichloromethane (2.2 mL)
was added aqueous 80% trifluoroacetic acid (TFA, 220 L) at room
temperature. After stirring for 1 h, the solvent was removed by
evaporation under an argon stream to give a crude compound that
was not subjected to further purification. The crude compound
was dissolved in methanol (3.0 mL), and then 0.1 M sodium hy-
droxide (2.4 mL, 0.24 mmol) was added at room temperature.
After stirring for 24 h, the mixture was concentrated by evapo-
ration. The residue was purified by gel filtration chromatography
a
-
D
-manno-2-octulopyranosyl)onate]]-
J4,5¼2.2 Hz, J5,6a¼5.0 Hz, J5,6b¼9.4 Hz, H-5III), 4.53 (ddd, 1H,
J7,8a¼4.0 Hz, J8a,8b¼12.4 Hz, H-8aI), 4.60 (dd, 1H, J7,8a¼4.0 Hz,
J8a,8b¼12.6 Hz, H-8aII), 4.71 (dd, 1H, J1,2¼3.4 Hz, J2,3¼11.4 Hz,
JNH,2¼10.0 Hz, H-2III), 4.75 (ddd, 1H, J3a,4¼11.4 Hz, J3e,4¼5.6 Hz,
J4,5¼2.0 Hz, H-4I), 4.85 (dd, 1H, J7,8b¼2.6 Hz, J8a,8b¼12.4 Hz, H-8bI),
4.94 (dd, 1H, J¼1.2 and 17.6 Hz, ]CH2), 4.96 (dd, 1H, J¼1.8 and
10.6 Hz, ]CH2), 5.03 (d, 1H, J1,2¼3.4 Hz, H-1III), 5.34 (dd, 1H,
J2,3¼11.4 Hz, J3,4¼3.2 Hz, H-3III), 5.34 (dd, 1H, J7,8b¼2.4 Hz,
J8a,8b¼12.6 Hz, H-8bII), 5.40 (dd, 1H, J3,4¼3.2 Hz, J4,5¼2.2 Hz, H-4III),
5.53 (ddd, 1H, J6,7¼9.8 Hz, J7,8a¼4.0 Hz, J7,8b¼2.6 Hz, H-7I), 5.66
(ddd, 1H, J6,7¼8.0 Hz, J7,8a¼4.0 Hz, J7,8b¼2.4 Hz, H-7II), 5.70 (m, 1H,
eCH]), 6.43 (d, 1H, JNH,2¼10.0 Hz, NHAc), 7.37e7.38 (m, 2H, ArI,
ArII), 7.40e7.46 (m, 6H, ArI, ArII), 7.51e7.59 (m, 4H, ArI, ArII),
a-D
-manno-2-octulopyr-
m
m
(Biogel P-2) to give compound 17 as colorless powder in 87% yield.
25
[
a
]
þ30.2 (c 0.5, H2O). 1H NMR (600 MHz, D2O):
d 1.62 (dd, 1H,
D
J3a,3e¼13.0 Hz, J3a,4¼12.6 Hz, H-3aII), 1.82 (dd, 1H, J3a,4¼12.4 Hz,
J3a,3e¼12.8 Hz, H-3aI), 1.91 (dd, 1H, J3a,3e¼12.8 Hz, J3e,4¼4.2 Hz, H-
3eI), 2.06 (dd, 1H, J3a,3e¼13.0 Hz, J3e,4¼4.8 Hz, H-3eII), 3.44 (dd, 1H,
J5,6¼2.4 Hz, J6,7¼8.8 Hz, H-6I), 3.46 (dd, 1H, J7,8a¼6.2 Hz,
J8a,8b¼11.6 Hz, H-8aII), 3.54 (dd, 1H, J5,6¼0.6 Hz, J6,7¼8.0 Hz, H-6II),
3.59e3.83 (m, 12H, H-8aI, H-8bI, H-7I, H-8bII, H-7II, H-7aIII, H-7bIII,
H-5III, H-4III, H-3III, OCH2), 3.87e3.90 (m, 3H, H-6III, H-5II, H-2III),
3.96 (ddd, 1H, J4,5¼3.0 Hz, J3e,4¼4.8 Hz, and J3a,4¼12.6 Hz, H-4II),
4.07 (br s, 1H, H-5I), 4.11 (ddd, 1H, J4,5¼2.0 Hz, J3e,4¼4.2, and
J3a,4¼12.6 Hz, H-4I), 5.06e5.08 (m, 1H, ]CH2), 5.17 (d, 1H,
J1,2¼1.8 Hz, H-1III), 5.19 (ddd, 1H, J¼1.4, 3.2, and 17.2 Hz, ]CH2),
7.93e8.07 (m, 8H, ArI, ArII). 13C NMR (150 MHz, CDCl3):
d 20.6,
20.75, 20.84 (AceCH3), 23.0 (NHAceCH3), 25.0 and 25.1 (Me), 31.7
(C-3II), 34.9 (C-3I), 47.6 (C-2III), 52.1 (OMeII), 52.4 (OMeI), 60.4 (C-
6III), 61.9 (C-8II), 62.4 (C-8I), 65.43 (OCH2e), 66.45 (C-5III), 66.8 (C-
4III), 67.4 (C-4I), 68.5 (C-3III), 68.6 (C-7I), 69.9 (C-4II), 70.2 (C-6II),
70.5 (C-7II), 70.6 (C-5I), 70.7 (C-6I), 72.1 (C-5II), 96.2 (C-2II), 97.9 (C-
1III), 99.2 (C-2I), 109.9 (Cisop), 117.0 (]CH2), 128.39, 128.42, 128.5,
128.6, 128.8, 129.3, 129.6, 129.70, 129.73, 129.8, 129.9 and 130.1 (ArI
and ArII), 133.0 (eCH]), 164.9, 165.1, 165.7, 166.2 (Bz: C]O), 168.3
(C-1I), 168.6 (C-1II), 170.1, 107.3, 170.5 (Ac: C]O). 170.9 (NHAceC]
O). IR(neat): 1746, 1723, 1278, 1249, 1217 cmꢁ1. ESI-HRMS calcd for
5.78e5.85 (m, 1H, eCH]). 13C NMR (150 MHz, D2O):
d
34.3 (C-3I),
C
66H73NO27: 1334.4268 [MþNa]þ. Found 1334.4253.
34.5 (C-3II), 62.9 (C-8I), 63.2 (C-8II), 63.9 (C-7III), 64.0 (OCH2), 66.1
(C-4II), 66.2 (C-5II), 66.3 (C-4III), 69.0 (C-7I), 69.2 (C-6III), 69.5 (C-
4I), 70.0 (C-2III), 70.2 (C-7II), 70.4 (C-3III), 71.9 (C-6I), 72.0 (C-6II),
72.6 (C-5III), 72.8 (C-5I), 100.0 (C-2I, C-2II), 101.1 (C-1III), 117.1 (]
CH2), 134.0 (eCH]), 174.87 (C-1I), 174.93 (C-1II). IR (neat): 3346,
3333, 1678, 1623 cmꢁ1. ESI-HRMS calcd for C26H41O21: 689.2149
[Mꢁ2NaþH]ꢁ. Found 689.2140.
3.8. 2-Acetamido-2-deoxy-a-D-galactopyranosyl-(1-5)-[O-(so-
dium 3-deoxy- -manno-2-octulopyranosylonate)]-(2-4)-so-
a-D
dium (allyl 3-deoxy-a-D-manno-2-octulopyranoside)onate
(16)
The procedure was similar to that described for compound 17.
The reaction was performed with 27.4 mg of 3,4,6-tri-O-acetyl-2-
3.10.
manno-2-octulo pyranosylonate)]-(2-4)-sodium (allyl 3-
deoxy- -manno-2-octulopyranoside)onate (18)
a-D-Mannopyranosyl-(1-5)-[O-(sodium 3-deoxy-a-D-
acetamido-2-deoxy-
[methyl (7,8-di-O-benzoyl-4,5-O-isopropylidene-3-deoxy-
manno-2-octulopyranosyl)onate]]-(2-4)-(allyl 7,8-di-O-benzoyl-
3-deoxy- -manno-2- octulopyranosyl)onate 15, 80% trifluoro-
acetic acid (0.9 mL), and 0.1 M sodium hydroxide (2.5 mL) to af-
a
-
D
-galactopyranosyl-
(1-5)-[methyl
O-
a
-
D
-
a-D
a
-
D
The procedure was similar to that described for compound 17.
The reaction was performed with 51.3 mg of 2,3,4,6-tetra-O-ace-
25
ford compound 16 (15.6 mg) in quantitative yield. [
a
]
þ116.5 (c
tyl-
benzoyl-4,5-O-isopropylidene-3-deoxy-
ranosyl)onate]]-(2-4)-(allyl 7,8-di-O-benzoyl-3-deoxy-a-D-
a
-
D
-mannopyranosyl-(1-5)-[methyl O-[methyl (7,8-di-O-
D
0.3, H2O). 1H NMR (600 MHz, D2O):
d
1.73 (dd, 1H, J3a,4¼12.6 Hz,
a-D
-manno-2-octulopy
J3a,3e¼13.0 Hz, H-3aII), 1.94e2.04 (m, 2H, H-3aI, H-3eI), 2.02 (s, 3H,
Ac), 2.10 (d, 1H, J3b,4¼4.4 Hz, J3a,3e¼13.0 Hz, H-3eII), 3.51e3.53 (m,
1H, H-6I), 3.54 (dd, J7,8a¼6.0 Hz, J8a,8b¼11.8 Hz, 1H, H-8aII), 3.66
(dd, 1H, J5,6¼1.0 Hz, J6,7¼8.0 Hz, H-6II), 3.66e3.75 (m, 5H, H-8aI,
H-7I, OCH2, H-6aIII, H-6bIII), 3.81e3.86 (m, 3H, H-8bII, H-8bI,
OCH2), 3.88e3.91 (m, 1H, H-7II), 3.94e3.99 (m, 4H, H-5II, H-3III, H-
4II, H-4III), 4.26 (ddd, 1H, J¼2.0, 5.4, 11.2 Hz, H-4I), 4.16 (dd, 1H,
J1,2¼3.4 Hz, H-2III), 4.17 (br s, 1H, H-5I), 4.25e4.27 (m, 1H, H-5III),
5.13e5.15 (m, 1H, ]CH2), 5.19 (d, 1H, J1,2¼3.4 Hz, H-1III),
5.23e5.28 (m, 1H, ]CH2), 5.86e5.92 (m, 1H, eCH]). 13C NMR
manno-2-octulopyranosyl)onate 13, 80% trifluoro acetic acid
(1.7 mL), and 0.1 M sodium hydroxide (5.0 mL) to afford 26.1 mg
(93%) of compound 18. [
a
]
25 þ80.4 (c 0.8, H2O). 1H NMR (600 MHz,
D
D2O):
d
1.70 (dd, 1H, J3a,3e¼12.8 Hz, J3a,4¼12.0 Hz, H-3aII), 1.90 (dd,
1H, J3a,3e¼12.2 Hz, J3a,4¼12.2 Hz, H-3aI), 2.01 (dd, 1H,
J3a,3e¼12.2 Hz, J3e,4¼4.4 Hz, H-3eI), 2.05 (dd, 1H, J3a,3e¼12.8 Hz,
J3e,4¼4.6 Hz, H-3eII), 3.49e3.53 (m, 1H, H-6I), 3.50e3.53 (m, 1H, H-
8aII), 3.62e3.72 (m, 5H, H-8aI, H-6II, H-7I, OCH2, and H-6aIII),
3.77e3.95 (m, 10H, H-4III, H-5II, OCH2, H-8bII, H-8bI, H-3III, H-7II, H-
6bIII, H-4II, and H-5III), 4.01e4.03 (m, 2H, H-4I and H-2III), 4.15 (br s,
1H, H-5I), 5.09e5.12 (m, 1H, ]CH2), 5.13 (d, 1H, J1,2¼1.6 Hz, H-1III),
5.21e5.24 (m, 1H, eCH]), 5.82e5.88 (m, 1H, eCH]). 13C NMR
(150 MHz, D2O):
d
22.0 (CH3), 34.5 (C-3I), 34.6 (C-3II), 50.3 (C-2III),
60.4 (C-6III), 62.8 (C-8I), 63.3 (C-8II), 64.1 (OCH2), 66.0 (C-4II), 66.6
(C-5II), 67.6 (C-3III), 68.4 (C-4III), 69.2 (C-7II), 70.3 (C-7I), 70.5 (C-
5III), 70.9 (C-4I), 71.9 (C-6II), 72.60 (C-6I), 72.63 (C-5I), 97.7 (C-1III),
100.4 (C-2II), 101.2 (C-2I), 117.0 (]CH2), 134.1 (eCH]), 174.7,
(150 MHz, D2O): d
34.4 (C-3I), 34.6 (C-3II), 60.5 (C-4III), 62.7 (C-8I),
63.3 (C-8II), 64.0 (OCH2), 65.9 (C-6III), 66.1 (C-4II), 66.7 (C-5II), 69.2
(C-7I), 70.1 (C-2III), 70.3 (C-3III), 70.5 (C-7II), 70.7 (C-4I), 71.7 (C-6II),
72.2 (C-6I), 72.7 (C-5III), 73.2 (C-5I), 100.00 (C-2I), 100.6 (C-1III),
101.5 (C-2II), 117.0 (]CH2), 134.0 (eCH]), 175.0 (C-1I), 175.1 (C-
1II). IR (neat): 3381, 3274, 1604, 1568 cmꢁ1. ESI-HRMS calcd for
175.0, 175.2 (3C, C-1I, C-1II, C]O). IR(neat): 3295, 1680, 1614 cmꢁ1
.
ESI-HRMS calcd for C27H42NO20: 700.2300 [Mꢁ2NaþH]ꢁ. Found
700.2294.
3.9.
3-deoxy-
m(allyl 3-deoxy-
L
-glycero-
-manno-2-octulopyranosylonate)]-(2-4)-sodiu-
-manno-2-octulopyranoside)onate (17)
a
-
D
-manno-Heptopyranosyl-(1-5)-[O-(sodium
C
25H39O20: 659.2035 [Mꢁ2NaþH]ꢁ. Found 659.2061.
a-D
a
-D
Acknowledgements
To a solution of 2,3,4,6,7-penta-O-acetyl-
heptopyranosyl-(1-5)-[methyl O-[methyl(7,8-di-O-benzoyl-4,5-O-
L
-glycero-
a
-
D
-manno-
This work was supported by JSPS KAKENHI Grant Number
23580474. We thank Professor Jun-ichi Tamura and Dr. Toshiki

3682
R. Yi et al. / Tetrahedron 70 (2014) 3675e3682
6. Paulsen, H.; Wulff, A.; Brenken, M. Liebigs Ann. Chem. 1991, 11, 1127e1145.
7. Ichiyanagi, T.; Fukunaga, M.; Tagashira, R.; Hayashi, S.; Nanjo, M.; Yamasaki, R.
Tetrahedron 2011, 67, 5964e5971.
Nokami for helpful discussions and are also grateful to Ms. Maki
Taniguchi for technical assistance.
8. Yu, B.; Tao, H. J. Org. Chem. 2002, 67, 9099e9102.
9. Kondo, H.; Ichikawa, Y.; Wong, C.-H. J. Am. Chem. Soc. 1992, 114, 8748e8750.
10. Nicolaou, K. C.; Caulfield, T. J.; Kataoka, H.; Stylianides, N. A. J. Am. Chem. Soc.
1990, 112, 3693e3695.
Supplementary data
Supplementary data associated with this article can be found in
the online version, at http://dx.doi.org/10.1016/j.tet.2014.04.024.
11. Yoshizaki, H.; Fukuda, N.; Sato, K.; Oikawa, M.; Fukase, K.; Suda, Y.; Kusumoto, S.
Angew. Chem., Int. Ed. 2001, 40, 1475e1480.
12. Yamasaki, R.; Takajyo, A.; Kubo, H.; Matsui, T.; Ishii, K.; Yoshida, M. J. Carbohydr.
Chem. 2001, 20, 171e180.
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