A new Kdo derivative for the synthesis of an inner-core disaccharide of lipopolysaccharides and lopooligosaccharides

Article abstract of DOI:10.1016/j.tet.2011.06.039

Methyl (7,8-di-O-benzoyl-4,5-O-isopropylidene-3-deoxy-d-manno-2-oct- ulopyranoside)onate was found to be a useful new intermediate in the synthesis of an inner-core oligosaccharide of lipooligosaccharides and lipopolysaccharides produced by gram-negative

Full text of DOI:10.1016/j.tet.2011.06.039

Tetrahedron 67 (2011) 5964e5971
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A new Kdo derivative for the synthesis of an inner-core disaccharide of
lipopolysaccharides and lopooligosaccharides
,
a
a
a
b
Tsuyoshi Ichiyanagi a , Mayumi Fukunaga , Ryoya Tagashira , Shie Hayashi , Masato Nanjo ,
*
Ryohei Yamasaki a
a Department of Life and Food Sciences, Faculty of Agriculture, Tottori University, Tottori 680-8553, Japan
b Department of Material Science, Faculty of Engineering, Tottori University, Tottori 680-8552, Japan
a r t i c l e i n f o
a b s t r a c t
Article history:
Methyl (7,8-di-O-benzoyl-4,5-O-isopropylidene-3-deoxy-D-manno-2-oct-ulopyranoside)onate was found
Received 16 February 2011
Received in revised form 10 June 2011
Accepted 11 June 2011
to be a useful new intermediate in the synthesis of an inner-core oligosaccharide of lipooligosaccharides
and lipopolysaccharides produced by gram-negative bacteria. This intermediate could be converted to
the corresponding glycosyl fluoride and 4,5-diol acceptor with ease. Syntheses of dimeric Kdo, O-(so-
Available online 17 June 2011
dium
octuropyranoside)onate, and O-(sodium 3-deoxy-
(allyl 3-deoxy- -manno-2-octuropyranoside)onate were successfully demonstrated.
Ó 2011 Elsevier Ltd. All rights reserved.
3-deoxy-
a
-D-manno-2-octuropyranosylonate)-(2e4)-sodium
(allyl
3-deoxy-a-D-manno-2-
a-D-manno-2-octuropyranosylonate)-(2e8)-sodium
Keywords:
Lipopolysaccharide
Lipooligosaccharide
a-D
3-Deoxy-D-manno-2-octulosonic acid
1. Introduction
an acceptor. The anomeric OH group can be easily converted to
glycosyl fluoride, phosphate, or trichloroacetimidate under
a
Lipopolysaccharides (LPSs) and lipooligosaccharides (LOSs) are
important surface antigens for a wide variety of gram-negative
bacteria. LPS is composed of O-antigen, a core oligosaccharide
(OS), and lipid A, whereas LOS consists of a core OS and lipid A. The
core OS moiety of an LPS or LOS consists of a structurally variable
region and a conserved inner-core OS. In its mono-, di-, or trimeric
standard conditions. After glycosylation or O-alkylation at the
anomeric position, acidic hydrolysis would give a 4,5-diol acceptor,
whereas base-catalyzed methanolysis would give a 7,8-diol ac-
ceptor. In this paper, we report the preparation of this Kdo in-
termediate from
be converted to its corresponding glycosyl donor and acceptor. Fi-
nally we demonstrated syntheses of dimeric Kdo, Kdo( 2e4)Kdo
and Kdo( 2e8)Kdo, which are a constituent of the conserved inner
D-mannose by simple operations, and that it could
form, 3-deoxy-D-manno-oct-2-ulosonic acid (Kdo) is a component
a
of the inner core.
a
Although many syntheses of monomeric Kdo from
D
-arabinose
core of LPSs and LOSs.
and
D
-mannose have been reported, reports pertaining to the
synthesis of dimeric Kdo (i.e., Kdo(
a
2e4)Kdo) are few.1e7 Because it
2. Results and discussion
is difficult to devise a suitable synthon for the synthesis of a Kdo-
containing oligosaccharide, a Kdo acceptor has typically been
synthesized from Kdo ammonium salt through a complex series of
operations, such as selective protection, deprotection, and chro-
matographic separation of protected products.
To alleviate this problem, we therefore designed and synthe-
sized methyl 7,8-di-O-benzoyl-4,5-O-isopropylidene-D-manno-
octulosonate as a synthon for oligosaccharides. This compound has
an acid-labile isopropylidene group, and a base-sensitive benzoyl
group for OH protection, and can be converted to either a donor or
Our designed Kdo derivative, 7,8-di-O-acyl-4,5-diisopropyliden-
-manno-octulosonate was constructed from 5,6-di-O-acyl-2,
D
3-O-isopropylidene-D-mannofuranose as follows: two-carbon elon-
gation by the Wittig reaction, dihydroxylation of the unsaturated
ester, cyclic sulfite formation, and cyclization. The starting mate-
rials, 5,6-di-O-acetyl (2) and 5,6-di-O-benzoyl furanose (3), were
prepared from 1-O-acetyl-2,3-O-isopropylidene-D-mannofuranose
(1)8 by treatment with acetic anhydride and benzoyl chloride, re-
spectively, followed by hydrolysis of the anomeric acetate in 99%
and 93% yield (Fig. 1).
To construct the carbon skeleton, two-carbon elongation of 5,6-
diacetate 2 and 5,6-dibenzoate 3 was examined. Treatment of 5,6-
diacetate 2 with methyl triphenylphosphoranylidene acetate in
* 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 2011 Elsevier Ltd. All rights reserved.
doi:10.1016/j.tet.2011.06.039

T. Ichiyanagi et al. / Tetrahedron 67 (2011) 5964e5971
5965
BzO
BzO
BzO
R1
H
Ac
Bz
Ac
Bz
R2
BzO
R1O
O
O
a
OH
CO2Me
OH
OH
CO2Me
1
2
3
4
5
Ac
Ac
Ac
H
O
R1O
H
O
HO
O
OR2
8
11
O
O
OBz
BzO
O
O
H
c
b
O
CO2Me
OH
12
R1O
R1O
R2O
O
R2O
H
OR3
O
CO2Me
OBz
OBz
O
BzO
O
O
BzO
O
OR3
CO2Me
O
O
O
CO2Me
O
O
O
CO2Me
R1
Ac
Ac
Bz
R2 R3
13α
13β
6
7
8
Ac
H
Bz
H
Ac
H
Scheme 1. Conditions: (a) OsO4, NMO, acetone/H2O, rt, 20 h, 96%; (b) (i)SOCl2, Et3N,
CH2Cl2, 0 ꢀC, 2 h, (ii) DBU, THF, ꢁ78 ꢀC, 0.5 h, and TMSCl, 0 ꢀC, 3.0 h, then 1 M HCl, 10 h,
84%,
a
/b
¼3/1; (c) allyl ethyl carbonate, Pd2(dba)3, dppb, THF, 65 ꢀC, 23 h, 58%.
RO
R
RO
H
O
For the synthesis of dimeric Kdo, a diol acceptor was prepared
by O-allylation at the anomeric position of 12, followed by acid-
catalyzed hydrolysis of the 4,5-O-isopropylidene group. Com-
pound 12 was treated with allyl ethyl carbonate in the presence of
9
10
Ac
Bz
CO2Me
O
O
Pd2(dba)3/dppb to give O-allylated 13
Although the diastereomeric ratio of starting material 12 was 3/1,
only trace amount of -O-allylated 13 could be detected. The
structure of 13 was determined by X-ray crystal structure analysis
(Fig. 2). The pyranose ring was found to have not a chair confor-
mation but rather a boat-like form. However, the molecule did not
completely assume the boat configuration because of strain caused
by steric repulsion between the methoxy carbonyl group and the
methyl group of the 4,5-isopropylidene unit.
Removal of the 4,5-di-O-isopropylidene group was accom-
plished in a few minutes by treatment with aqueous 90% TFA to give
4,5-diol 14 in quantitative yield. Treatment with 80% aqueous acetic
acid at 80 ꢀC was also effective for removal of the isopropylidene
group but a longer reaction time (>7 h) was required for the re-
action to reach completion. The other side, methanolysis of benzoyl
esters at 7- and 8-position gave the corresponding 7,8-diol 15
(Scheme 2).
a in moderate yield (58%).
Fig. 1.
b
b
toluene at 80 ꢀC afforded a mixture of 7,8-diacetyl unsaturated
ester 6 (E/Z¼10/1), 6,8-diacetyl ester 7 from an unexpected acetyl
migration, and cyclized product 9. Although 7 was isolated by silica
gel column chromatography, compounds 6 and 9 could not be
separated completely. When the reaction was carried out at 110 ꢀC,
only the undesired cyclic product 9 was obtained in quantitative
yield. Treatment of a mixture of 6 and 9 under Wittig reaction
conditions at 110 ꢀC gave the compound 9 convergently. We found
that the elongation reaction did not proceed under 80 ꢀC, but mi-
gration of the acetyl group from the 7- to 6-position of 6 could not
be prevented even when the reaction was carried out at 80 ꢀC.
Therefore, to avoid the undesired migration, we abandoned the use
of the acetyl group for hydroxyl protection, and instead turned our
attention to the benzoyl group. Treatment of benzoyl-protected
furanose 3 with 1.2 equiv of Wittig reagent at 55 ꢀC afforded the
a
a,b-unsaturated ester 8 in 97% yield as a mixture of geometric
OBz
BzO
isomers. The E/Z ratio was 10/1, as determined by comparison of the
peak areas of H-2 and H-3 in the 1H NMR spectra. This elongation
reaction was also sensitive to temperature. When the reaction was
carried at 80 ꢀC, an undesired cyclized product (10) was formed in
quantitative yield. Using of HornereWadswortheEmmons condi-
tions instead of Wittig conditions also gave 10. From these results,
we selected 7,8-di-O-benzoyl-2-octenoate 8 for later studies.
HO
O
d
e
HO
CO2Me
O
14
13α
OH
HO
O
O
Dihydroxylation of a,b-unsaturated ester 8 with osmium tetra-
O
CO2Me
oxide and N-methylmorphorine N-oxide (NMO) gave triol 11 as
a mixture of diastereomers in 96% yield (Scheme 1), along with
a small amount of 10 (<3%). To avoid the formation of 10, it was
necessary to add NMO in small portions to the reaction mixture
containing the catalyst. The subsequent reaction was carried out
without further purification because the newly formed stereo-
center would be destroyed later.
To construct a pyranose ring, the 2- and 3-hydroxyl groups of
triol 11 were converted to cyclic sulfites by treatment with thionyl
chloride. The sulfites were sequentially treated with DBU in the
presence of TMSCl and with 1 M HCl, in accordance with Kuboki’s
procedure,9 to give Kdo derivative 12 (Scheme 1) in good yield
(82%) with a moderate anomeric ratio (3/1 to 5/1).
O
15
Scheme 2. Conditions: (a) 90% TFA aq, rt, 0.5 h, quant. (b) NaOMe, MeOH, rt, 18 h,
quant.
On the other hand, treatment of 12 with DAST10 afforded gly-
cosyl fluoride 16 as a mixture of anomers in good yield (81%), along
with a small amount of an undesired glycal with an a,b-unsaturated
ester (11%).11 The anomeric ratio of 16 was 5/2, and the major iso-
mer was easily isolated by crystallization from ethyl acetate and
hexane. The anomeric configuration of the major product was
presumed to be
a based on a compare with the NMR data of the

5966
T. Ichiyanagi et al. / Tetrahedron 67 (2011) 5964e5971
Fig. 2. Crystal structure of 13a.
a and 17b
reported by Imoto.12
Table 1
corresponding Kdo derivatives 17
Partial 1H and 13C NMRa data for glycosyl fluoride derivatives 16
a, 16b, 17a, and 17b
Table 1 lists data from partial 1H and 13C NMR spectra of fluorides
16a and 16b and 17a and 17b
. In the 1H spectra, clear differences in
16
a
16
b
17
a
17
b
the chemical shifts at H-3 between major 16 and minor 16 were
observed. The difference in chemical shift between the H-3e and
H-3a
H-3e
H-4
2.08
3.04
4.58
15.5
18.0
3.0
2.49
2.63
4.66
16.0
32.5
4.0
1.98
3.07
4.57
15.5
18.0
3.0
2.14
2.42
4.62
16.0
34.0
4.0
the H-3a of major 16 (
0.14 ppm). Furthermore, the coupling constants of H-3a, H-3e,
and F-2 of major 16 were similar to those of compound 17 , and the
d 0.95 ppm) was greater than that of minor 16
2J3a,3e
3J3a,F
3J3a,4
3J3e,F
3J3e,4
(d
a
chemical shift at C-3 of major 16 was also higher than that of minor
4.0
7.0
11.0
2.5
4.0
4.0
10.0
2.0
16 in the 13C spectra. Therefore, we presumed the configuration of
major 16 to be
a (Fig. 3).
C-1
C-2
166.0
107.5
31.0
34.5
7.5
167.0
107.1
30.7
39.5
<1.0
166.1
107.3
30.7
35.0
8.5
167.5
107.5
30.8
39.5
<1.0
Glycosylation of the fluoride donor 16a with the acceptor 14 in
the presence of boron trifluoride etherate was carried out at ꢁ20 ꢀC
C-3
1JC2,F
to give a2e4 and b2e4 linked dimeric Kdo 18a and 18b in 30% yield
3JC4,F
and the ratio was 5/1(Scheme 3). However, as Oikawa showed that
the addition of tertiaryamine was effective for their glycosylation,
the presence of triethylamine increased the yield of 18a/b upto 72
a
Data were acquired in CDCl3 at 25 ꢀC. The 1H and 13C NMR chemical shifts (ppm)
were determined by comparing 2D-NMR data (DQF-COSY, HMQC and HMBC), and
the J couplings (Hz) were obtained by analyzing either the DQFeCOSY or 1D NMR
spectrum.
percent.13 The major and minor product could be separated by silica
gel column chromatography. The structure of the major Kdo dimer
was determined by analysis of 2D-NMR analysis (COSY, HMQC, and
HMBC). From the COSY and HMQC spectra, we were able to identify
the endocyclic protons, the hydroxyl proton, and the endocyclic
carbon atoms of each residue of 18. The linkage of the newly formed
glycoside was determined by HMBC analysis. Fig. 4 shows part of
the COSY and HMBC spectra. The cross peaks in the COSY spectrum
(Kdo H-4/H-5 and Kdo H-5/Kdo OH; panel A) and the cross-relay
peak in the HMBC spectrum (Kdo H-4/Kdo C-20; panel B) con-
OBz
O
OBz
O
BzO
O
BzO
O
O
CO2Me
O
F
F
16α
CO2Me
16β
O
O
O
O
O
O
firmed that the donor 13a is linked to the 4-position of the acceptor
14. The minor component was also formed a 2e4 linkage, which
was confirmed in the same manner.
O
F
17α
O
O
CO2Me
O
F
CO2Me
The anomeric configuration of major product 18 was a, which
17β
was determined by comparison of the difference in chemical shift
between H-3a and H-3b proton in the 1H NMR of each major and
Fig. 3.

T. Ichiyanagi et al. / Tetrahedron 67 (2011) 5964e5971
5967
OBz
OBz
products was unsatisfactory, the major product was
a
2e8 linked
BzO
HO
BzO
O
O
OBz
BzO
Kdo dimmer 19. Minor products could not be determined accu-
rately. In this case, we found that the yield of the Kdo dimer could
not be improved even if the reaction performed at ꢁ78 ꢀC and the
use of excess amount (5 equiv) of boron trifluoride etherate was not
suitable because the migration of 4,5-isopropylidene group of the
acceptor 15 and other reactions were occurring. Thus further
optimization of reaction conditions is necessary.
HO
MeO2C
O
a
O
O
O
O
O
BzO
BzO
O
CO2Me
16α
14
O
CO2Me
MeO2C
O
O
18α
18β
Scheme 3. Conditions: (a) BF3$OEt2, Et3N, MS 5 A, CH2Cl2, 0 ꢀC, 1.5 h, 72% (
a
/
b
¼5/1).
ꢀ
Fig. 4. Partial COSY (panel A) and HMBC (panel B) spectra of compound 18a
in CDCl3 at 25 ꢀC; only partial 1H/1H cross peaks (A) and cross-relay peak (B) are labeled.
minor product. The difference for the major isomer was
whereas that for the minor one was 0.04 ppm; therefore, the
configuration of major product was identified as and that of mi-
nor product was identified as
The reaction of 7,8-diol 15 and fluoride 16
d
1.04 ppm,
Finally, hydrolysis of the isopropylidene group of Kdo dimers
(18a and 19) with aqueous trifluoroacetic acid and subsequent
hydrolysis in 0.1 M sodium hydroxide to remove the ester groups
afforded fully deprotected dimeric Kdo 20 and 21 as a disodium salt
in quantitative yield (Scheme 4). All 1H and 13C NMR data of syn-
thetic 20 and 21 were consistent with reported data.14,15
d
a
b.
a
was also given the
dimeric Kdo (Scheme 4). The structure of 19 was determined by 2D-
NMR described in the above manner. Although the yield of dimeric
3. Conclusions
OBz
O
OH
O
BzO
O
O
HO
HO
HO
15
Methyl 7,8-di-O-benzoyl-4,5-O-isopropylidene-D-manno-octu-
losonate 12 was easily converted to glycosyl fluoride and a glycosyl
acceptor, and was a useful synthon for the synthesis of dimeric Kdo,
CO2Na
CO2Me
a
b
O
O
HO
HO
HO
O
16α
O
O
CO2Na
CO2Me
HO
O
O-(sodium 3-deoxy-
sodium (allyl 3-deoxy-
O-(sodium 3-deoxy-
sodium (allyl 3-deoxy-
which are highly conserved disaccharides in the inner-core OS of
LPSs and LOSs. Because different conditions can be employed to
remove the benzoyl and isopropylidene protecting groups, 12 is
able to serve as an acceptor for the synthesis of Kdo(2e4)Kdo and
a-D-manno-2-octulopyranosylonate)-(2e8)-
O
O
a
-D
-manno-2-octulopyranoside)onate 20 or
19
20
a
-D-manno-2-octuropyranosylonate)-(2e4)-
a
-D-manno-2-octuropyranoside)onate 21,
OH
HO
HO
O
NaO2C
O
b
O
O
HO
HO
CO2Na
18α
HO
HO
21
Kdo(2e8)Kdo. The 5-hydroxyl group of compound 18
a can form
ꢀ
a connection with several types of monosaccharide and oligosac-
charide donors to afford a 4,5-branched core OS. The allyl group at
Scheme 4. Conditions: (a) BF3$OEt2, Et3N, MS 5 A, CH2Cl2, (b) 80% TFA aq, CH2Cl2, rt,
then 1.0 M NaOH, MeOH.

5968
T. Ichiyanagi et al. / Tetrahedron 67 (2011) 5964e5971
the reducing end can be functionalized, and can serve as a con-
nection point to a carrier. Therefore, 12 is expected to be a useful
intermediate for the synthesis of inner-core OSs containing Kdo as
a reducing end residue.
column chromatography (hexane/ethyl acetate¼3/2) to give 5
(4.19 g, 98%) as a colorless syrup. 1H NMR (400 MHz, CDCl3):
1.27
d
(s, 3H, Me), 1.49 (s, 3H, Me), 4.59 (dd, 1H, J1,2¼4.0, J2,3¼8.0 Hz, H-2),
4.62e4.67 (m, 2H, H-3 and 4), 4.86e4.89 (m, 2H, H-6a and 6b), 5.45
(d, 1H, J1,2¼4.0 Hz, H-1), 5.73 (m, 1H, H-5), 7.42e8.03 (m, 10H, Ar).
4. Experimental
4.1. General
13C NMR (125 MHz, CDCl3):
d 24.7 (CH3), 25.6 (CH3), 63.9 (C-6), 69.8
(C-5), 78.2 (C-4), 79.6 (C-3), 85.2 (C-1), 101.21 (C-1), 113.0 (Cisop),
128.3, 129.6, 129.7, 129.86, 130.0, 133.0, and 133.1 (Ar), 165.3 (C]O),
166.3 (C]O). Anal. Calcd for C23H24O8: C, 64.45; H, 5.83. Found C,
64.43; H, 5.66.
Optical rotation was measured with a Horiba SEPA-200 or SEPA-
500 polarimeter, and melting point (uncorrected) was measured
with
a
Yanagimoto micro melting point apparatus. High-
4.1.3. Methyl 7,8-di-O-benzoyl-4,5-O-isopropylidene-2-octenoate
(8). Methyl (triphenylphosphoranylidene)acetate (1.67 g, 5.00 mmol)
was slowly added to a solution of 5,6-di-O-benzoyl-2,3-O-iso-
performance liquid chromatography (HPLC) was performed on
a Shimadzu HPLC system that consisted of an LC-AD10A pump, SPD-
10A UV detector, and a C-R8A recorder. All NMR spectra were
recorded at 25 ꢀC on a JEOL JNM-ECP 500 MHz spectrometer or
a Brucker Avance II 600 MHz NMR spectrometer.1H NMR spectra are
referenced to internal standards of the residual protonated solvent
peaks: dH 7.24 ppm for solutions in CDCl3, and dH 4.75 ppm for so-
lutions in D2O, at 25 ꢀC. 13C NMR spectra were recorded at 150 MHz
propylidene- -mannofuranose 5 (1.87 g, 3.87 mmol) in toluene
D
(44 mL). The mixture was heated at 55 ꢀC and stirred for 21 h. After
cooling to room temperature, the reaction solution was directly
purified by silica gel column chromatography (dichloromethane/
ethyl acetate¼5/1) to give an E/Z mixture of compound 8 (1.85 g,
97%) as a colorless syrup. 1H NMR (500 MHz, CDCl3):
d 1.37 (s, 3H,
and are referenced to internal CDCl3
(
dC 77.0 ppm) or to external
Me), 1.56 (s, 3H, Me), 2.62 (br s, 1H, OH), 3.69 (s, 0.27H, OMe), 3.73
(s, 2.73H, OMe), 3.96 (dd, 1H, J5,6¼2.5, J6,7¼8.0 Hz, H-6), 4.42
(dd, 1H, J4,5¼7.0, J5,6¼2.5 Hz, H-5), 4.65 (dd, 1H, J7,8a¼3.0,
J8a,8b¼12.5 Hz, H-8a), 4.81 (dd, 1H, J3,4¼6.5, J4,5¼7.0 Hz, H-4), 4.87
(dd, 1H, J7,8b¼6.0, J8a,8b¼12.5 Hz, H-8b), 5.48 (ddd, 1H, J6,7¼8.0,
J7,8a¼3.0, J7,8b¼6.0 Hz, H-7), 5.99 (d, 0.09H, J2,3¼11.5 Hz, H-2), 6.12
(d, 0.91H, J2,3¼15.5 Hz, H-2), 6.57 (d, 0.09H, J2,3¼11.5 Hz, H-3), 7.11
(d, 0.91H, J2,3¼15.5 Hz, H-3), 7,42e8.00 (m, 5H, Ar). 13C NMR
acetone (dC 31.07 ppm). Mass spectrometry (MS) was performed by
positive- and negative-mode electrospray ionization on a Thermo
Scientific LTQ Orbitrap XL and a Waters LCT Premier spectrometer.
For high-precision measurements, the spectra were obtained by
scanning voltage over a narrow mass range at 10,000 resolution.
Matrix-assisted laser desorption/ionization time-of-flight (MALDI-
TOF)-MS analysis was performed on an AutoFlex II system from
Bruker Daltronics. Elemental analysis was carried out on a Vario EL
CUBE and a Vario EL III from Elementar. Silica gel 60 (E. Merck) was
used for flash column chromatography (0.040e0.063 mm) and open
column chromatography (0.063e0.200 mm). Silica Gel 60 F254
(E. Merck) was used for thin-layer chromatography (TLC), and
compounds were detected under UV light (254 nm) or by spraying
with 10% or 5% H2SO4 in MeOH and then heating the plates at 200 ꢀC
for 3 min.
(125 MHz, CDCl3):
d
23.9 and 26.6 (Me0) 24.8 and 26.9 (Me), 51.6
(OMe0), 51.8 (OMe,), 63.4 (C-8), 64.4 (C-80), 67.6 (C-60) 68.3 (C-6),
70.1 (C-70), 72.80(C-7), 76.7 (C-4 and C40), 76.9 (C-5 and C-50), 109.8
(Cisop), 109.2 (C isop), 120.2 (C-30), 123.6 (C-3), 128.5, 128.6, 129.7,
129.9, 133.2, and 133.5 (Ar), 128.4, 128.5, 129.6, 129.7, 133.0, and
133.3 (Ar0), 143.1 (C-2), 148.6 (C-20), 166.1 (C]O), 166.3 (2C]O),
166.4 (C]O), 170.6 (C-1) 171.2 (C-10). Anal. Calcd for C26H28O9: C,
64.45; H, 5.83. Found C, 64.43; H, 5.66.
4.1.1. 1-O-Acetyl-5,6-di-O-benzoyl-2,3-O-isopropylidene-
a
-
D
-man-
4.1.4. Methyl (7,8-di-O-benzoyl-4,5-O-isopropylidene-3-deoxy-D-manno-
nofuranose (3). Triethylamine (7.1 mL, 51.2 mmol) and benzoyl
chloride (3.3 mL, 28.4 mmol) were added to a solution of 1-O-acetyl-
2,3-O-isopropylidene-a-D-mannofuranose 1 (3.37 g, 12.85 mmol)
2-octulopyranoside)onate (12). A solution of compound 8 (2.5 g,
5.1 mmol) in acetone (8.0 mL) was added to a solution of N-
methylmorpholine N-oxide (725 mg, 6.2 mmol) and 1% OsO4 aq
(5.3 mL, 0.21 mmol) in acetone (8.0 mL) and water (8.0 mL) at 0 ꢀC.
After being vigorously stirring for 20 h, the mixture was concen-
trated to remove acetone, and the resulted solution was extracted
with ethyl acetate. The combined organic layer was washed with
brine, dried over anhydrous sodium sulfate, filtered, and evapo-
rated. The residue was purified by silica gel column chromatogra-
phy (ethyl acetate/hexane¼5/1) to give methyl 7,8-di-O-benzoyl-
2,3,6-trihydroxyl-4,5-O-isopropylidene-2-octanoate (11) as a mix-
ture of diastereomers as a colorless syrup (2.5 g, 96%). Di-
astereomers were not further purified. The diastereomers of methyl
7,8-di-O-benzoyl-2,3,6-trihydroxyl-4,5-O-isopropylidene-2-octanate
11 (2.1g, 2.0 mmol) were dissolved in dichloromethane (36 mL).
Triethylamine (2.8 mL, 20 mmol) was added to the solution, and
then thionyl chloride (0.64 mL, 9.0 mmol) was added at 0 ꢀC. After
stirring for 2 h, the mixture was poured into satd NH4Cl aq, and
extracted with ethyl acetate. The organic layer was washed with
brine, dried over sodium sulfate, filtered, and concentrated. The
residue was dissolved in THF (36 mL), and treated with DBU
(2.4 mL, 16.2 mmol) at ꢁ78 ꢀC. After stirring for 0.5 h, chloro-
trimethylsilane (2.0 mL, 15.4 mmol) was added to the mixture,
which was warmed to room temperature and stirred for 3.0 h. The
mixture was treated with 8.0 mL of 1 M HCl for 10 h, neutralized
with satd NaHCO3, and extracted with ethyl acetate. The organic
layer was dried over sodium sulfate, filtered, and concentrated. The
residue was purified by sílica gel column chromatography (hexane/
and 4-N,N-dimethylaminopyridine (50 mg) in dichloromethane
(15 mL) at 0 ꢀC under argon. After stirring for 14 h, the reaction
mixture was poured into satd sodium bicarbonate and extracted
with dichloromethane. The combined organic layer was washed
with brine, dried over anhydrous sodium sulfate, filtered, and
evaporated. The residue was crystallized from ethyl acetate and
hexane to obtain 3 as a colorless crystal (5.76 g, 95%). Mp
106e107 ꢀC; [a 25
]
D
þ26.9 (c 1.00, CHCl3); 1H NMR (500 MHz, CDCl3):
d
1.29 (s, 3H, Me), 1.52 (s, 3H, Me), 2.03 (s, 3H, Ac), 4.49 (dd, 1H,
J3,4¼8.0, J4,5¼7.0 Hz, H-4), 4.64 (dd, 1H, J2,3¼6.0, J3,4¼8.0 Hz, H-3),
4.71 (d, 1H, J2,3¼6.0 Hz, H-2), 4.90 (dd, 1H, J5,6a¼8.0, J6a,6b¼12.5 Hz,
H-6a), 4.91 (dd, 1H, J5,6b¼5.6, J6a,6b¼12.5 Hz, H-6b), 5.74 (ddd, 1H,
J4,5¼7.0, J5,6a¼8.0, J5,6b¼5.5 Hz, H-5), 6.22 (s, 1H, H-1), 7.42e8.02 (m,
10H, Ar). 13C NMR (125 MHz, CDCl3):
d 20.8 (CH3), 24.9 (CH3), 26.0
(CH3), 63.8 (C-6), 69.6 (C-5), 79.2 (C-4), 80.3 (C-2), 84.7 (C-3), 100.5
(C-1), 113.6 (Cisop), 128.3, 128.4, 129.6, 129.7, 129.86, 129.93, 132.9,
and 133.1 (Ar), 165.2 (C]O), 166.0 (C]O), 169.1 (C]O). Anal. Calcd
for C25H26O9: C, 64.48; H, 5.65. Found C, 64.16; H, 5.89.
4.1.2. 5,6-Di-O-benzoyl-2,3-O-isopropylidene-
(5). 1-O-Acetyl-5,6-di-O-benzoyl-2,3-O-isopropylidene-
D
-mannofuranose
-man-
a-D
nofuranose 3 (4.69 g, 9.97 mmol) was dissolved in a mixed solvent
(25% NH3 aq/THF/MeOH¼1/13/13, 176.5 mL) at 0 ꢀC. The mixture
was stirred for 17.5 h, diluted with toluene, and concentrated by
evaporation of the solvent. The residue was purified by silica gel

T. Ichiyanagi et al. / Tetrahedron 67 (2011) 5964e5971
5969
ethyl acetate¼3/2 to 1/1) to afford an
a
/
b
mixture of compound 12
1.5 Hz, CH]CH2), 5.28 (dddd, 1H, J¼17.0 1.5, 1.5, and 1.5 Hz, CH]
CH2), 5.71 (ddd, 1H, J6,7¼8.0, J7,8a¼5.5, J7,8b¼2.5 Hz, H-7), 5.91 (m,
1H, CH]CH2), 7.40e7.44 (m, 4H, Ar), 7.52e7.56 (m, 2H, Ar),
as a colorless foam (1.7 g, 84%, major/minor¼3/1). Major isomer: 1H
NMR (500 MHz, CDCl3): d 1.20 (s, 3H, Me), 1.47 (s, 3H, Me), 1.94 (dd,
1H, J3a,3e¼14.0, J3a,4¼5.0 Hz, H-3a), 2.47 (dd, 1H, J3e,4¼7.5,
J3a,3e¼14.0 Hz, H-3e), 3.82 (s, 3H, OMe), 4.28 (dd, 1H, J4,5¼6.0,
J5,6¼2.5 Hz, H-5), 4.50 (dd, 1H, J5,6¼2.5, J6,7¼7.5 Hz, H-6), 4.52 (ddd,
1H, J3e,4¼7.5, J3a,4¼5.0, J4,5¼6.0 Hz, H-4), 4.75 (dd, 1H, J7,8a¼5.0,
J8a,8b¼12.0 Hz, H-8a), 4.84 (dd, 1H, J7,8b¼3.0, J8a,8b¼12.0 Hz, H-8b),
5.71 (ddd, 1H, J6,7¼7.5, J7,8b¼3.0, J7,8a¼5.0 Hz, H-7), 7.37e7.45 (m,
4H, Ar), 7.52e7.58 (m, 2H, Ar), 7.95e8.03 (m, 4H, Ar). 13C NMR
8.02e8.05 (m, 4H, Ar). 13C NMR (125 MHz, CDCl3):
d 25.2 (Me), 26.9
(Me), 33.6 (C-3), 52.4 (OMe), 63.2 (OCH2e), 65.6 (C-8), 70.3 (C-4),
70.8 (C-6), 70.9 (C-7), 71.0 (C-5), 98.5 (C-2), 109.6 (Cisop) 117.0
(CH2]),128.36,128.43,1323.0,133.2, and 133.2 (Ar),133.2 (eCH]),
165.3 (C]O), 166.2 (C]O), 169.0 (C-1).
4.1.6. Methyl (allyl 7,8-di-O-benzoyl-3-deoxy-
octulopyranoside)onate (14). To a solution of methyl (allyl 7,8-di-O-
benzoyl-4,5-O-isopropylidene-3-deoxy- -manno-2-octulopyranoside)
a-D-manno-2-
(125 MHz, CDCl3):
d 25.8 (Me) 27.3 (Me), 32.6 (C-3), 53.2 (OMe),
63.1 (C-8), 68.4 (C-6), 69.9 (C-4), 70.8 (C-5), 70.9 (C-7), 94.7 (C-2),
109.5 (Cisop), 128.47, 128.51, 129.7, 129.8, 129.6, 132.0, 133.1, and
133.3 (Ar), 169.9 (C-1). Minor isomer: 1H NMR (500 MHz, CDCl3):
a-D
onate 13 (167.0 mg, 0.31 mmol) in dichloromethane (17 mL) was
added 90% aqueous trifluoroacetic acid (1.7 mL) at room tempera-
ture. The mixture was stirred for 30 min, and then the solvent was
removed by evaporation under an argon stream. The residue was
purified by silica gel column chromatography (hexane/ethyl
d
1.30 (s, 3H, Me), 1.58 (s, 3H, Me), 2.33 (dd, 1H, J3a,3e¼14.0,
J3a,4¼5.0 Hz, H-3a), 2.49 (dd, 1H, J3a,3e¼14.0, J3e,4¼8.0 Hz, H-3e),
3.64 (s, 3H, OMe), 4.41 (dd, 1H, J4,5¼8.0, J5,6¼2.5 Hz, H-5), 4.09 (dd,
1H, J5,6¼2.5, J6,7¼8.0 Hz, H-6), 4.74 (dd, 1H, J3a,4¼5.0, J3e,4¼8.0,
J4,5¼8.0 Hz, H-4), 4.70 (dd, 1H, J7,8a¼5.0, J8a,8b¼10.5 Hz, H-8a), 4.87
(dd, 1H, J7,8b¼2.5, J8a,8b¼10.5 Hz, H-8b), 5.60 (ddd, 1H, J6,7¼8.0,
J7,8a¼5.0, J7,8b¼2.5 Hz, H-7), 7.37e7.45 (m, 4H, Ar), 7.52e7.58 (m, 2H,
acetate¼1/2) to give a colorless syrup (151 mg, 97%). [a 25
þ60.4 (c
]
D
0.99, CHCl3). 1H NMR (600 MHz, CDCl3):
d
1.99 (dd, 1H, J3a,4¼12.0,
J3a,3e¼12.5 Hz, H-3a), 2.25 (dd, 1H, J3e,4¼5.0, J3a,3e¼12.5 Hz, H-3e),
3.78 (s, 3H, OMe), 3.83 (dd, 1H, J4,5¼3.5, J5,6¼0.5 Hz, H-5), 3.91 and
4.00 (m, 1H each, OCH2), 4.02 (dd, 1H, J5,6¼0.5, J6,7¼5.5 Hz, H-6),
4.14 (ddd, 1H, J3a,4¼12.0, J3e,4¼5.0, J4,5¼3.5 Hz, H-4), 4.76 (dd, 1H,
J7,8a¼4.5, J8a,8b¼12.0 Hz, H-8a), 4.91 (dd, 1H, J7,8b¼2.5,
J8a,8b¼12.0 Hz, H-8b), 5.03 (dddd, J¼10.5, 1.5, 1.5 and 1.5 Hz, CH]
CH2), 5.12 (dddd, J¼17.0, 1.5, and 1.5 Hz, CH]CH2), 5.69e5.76 (m,
1H, CH]CH2), 5.75 (ddd, 1H, J6,7¼5.5, J7,8a¼4.5, J7,8b¼2.5 Hz, H-7),
7.41e7.44 (m, 4H, Ar), 7.55e7.59 (m, 2H, Ar), 8.00e8.02 (m, 4H, Ar);
13C NMR 35.1 (C-3), 52.7 (OCH3), 63.3 (C-8), 64.6 (OCH2), 65.4 (C-4),
65.8 (C-5), 70.3 (C-7), 70.4 (C-6), 99.2 (C-2), 116.5 (]CH2), 128.5,
128.6, 128.9,1296, 129.7, 130.0, 133.28, and 133.9 (Ar), 133.3
(eCH]), 166.3 (C]O), 166.9 (C]O), 168.4 (C-1). Anal. Calcd for
C26H29O10: C, 62.39; H, 5.64. Found C, 62.24; H, 5.70.
Ar), 7.95e8.03 (m, 4H, Ar). 13C NMR (125 MHz, CDCl3):
d 24.4 (Me)
26.1 (Me), 31.0 (C-3), 52.8 (OMe), 62.9 (C-8), 60.4 (C-6), 70.3 (C-4),
72.2 (C-5), 71.0 (C-7), 95.9 (C-2), 110.0 (Cisop), 128.3, 128.4, 129.9,
130.0, 130.6, 133.1, and 133.2 (Ar), 169.0 (C-1). Anal. Calcd for
C26H29O10: C, 62.39; H, 5.64. Found C, 62.11; H, 5.67.
4.1.5. Methyl (allyl 7,8-di-O-benzoyl-4,5-O-isopropylidene-3-deoxy-
a-D
-manno-2-octulopyranoside)onate (13
a and 13b). To a solution
of methyl (7,8-di-O-benzoyl-4,5-O-isopropylidene-3-deoxy-
D-
manno-2-octulopyranoside)onate 12 (623.2 mg, 1.25 mmol) and
Pd(dba)2 (17.9 mg, 0.03 mmol) in THF (10 mL), a solution of 1,4-
bis(diphenylphosphino)butane (53.1 mg, 0.13 mmol) and ethyl al-
lyl carbonate (328 mL, 2.49 mmol) in THF was added under argon.
The reaction mixture was refluxed for 23 h, cooled to room tem-
perature, and concentrated. Purification of the residue by silica gel
column chromatography (toluene/hexane/ethyl acetate¼5/1/1)
gave 314 mg of compound 13 as a colorless solid (58%). Further
recrystallization from ethyl acetate and hexane gave the sample
4.1.7. Methyl (allyl 4,5-O-isopropylidene-3-deoxy-
octulopyranoside)onate (15). To a solution of methyl (allyl 7,8-di-O-
benzoyl-4,5-O-isopropylidene-3-deoxy- -manno-2-octulopyranoside)
onate 13 (210.0 mg, 0.38 mmol) was added 28% sodium meth-
oxide (50 L) at room temperature. After stirring for 18 h, the
a-D-manno-2-
a-D
a
m
used in X-ray analysis. Crystallographic data for compound 13
a
mixture was neutralized by addition of the acetic acid, diluted with
toluene, and evaporated. The residue was purified by silica-gel
column chromatography (EtOAc as an eluent) to give compound
have been deposited in the Cambridge Crystallographic Data Centre
as supplementary publication number CCDC 804059. Compound
13
CDCl3):
a
: mp 116e117 ꢀC; [a 25
]
þ18.3 (c 1.03, CHCl3), 1H NMR (500 MHz,
15 as colorless syrup (129 mg, quant.) [a 25
]
þ43.8 (c 1.3, CHCl3), 1H
D
D
d
1.23 (s, 3H, Me), 1.45 (s, 3H, Me), 2.01 (dd, 1H, J3a,3e¼15.5,
NMR (600 MHz, CDCl3): d 1.25 (s, 3H, Me), 1.36 (s, 3H, Me), 1.90 (dd,
J3a,4¼3.5 Hz, H-3a), 2.76 (dd, 1H, J3e,4¼4.5, J3a,3e¼15.5 Hz, H-3e),
3.79 (s, 3H, OMe), 3.84 (dddd, 1H, J¼12.5, 5.5, 1.5, and 1.5 Hz, OCH2),
4.21 (dd, 1H, J5,6¼1.8, J6,7¼7.5 Hz, H-6), 4.31 (dddd, 1H, J¼12.5, 5.5,
1.5, and 1.5 Hz, OCH2), 4.32 (dd, 1H, J4,5¼7.5, J5,6¼1.8 Hz, H-5), 4.54
(dd, 1H, J3a,4¼3.5, J3e,4¼4.5, J4,5¼7.5 Hz, H-4), 4.72 (dd, 1H,
J8a,8b¼12.3, J7,8a¼5.0 Hz, H-8a), 4.97 (dddd, 1H, J¼10.5, 1.5, 1.5, and
1.5 Hz, CH]CH2), 5.01 (dd, 1H, J7,8b¼2.3, J8a,8b¼12.3 Hz, H-8b), 5.11
(dddd, 1H, J¼17.0, 1.5, 1.5, and 1.5 Hz, CH]CH2), 5.71 (m, 1H, CH]
CH2), 5.75 (ddd, 1H, J6,7¼7.5, J7,8a¼5.0, J7,8b¼2.3 Hz, H-7), 7.39e7.44
(m, 4H, Ar), 7.52e7.56 (m, 2H, Ar), 7.99e8.03 (m, 4H, Ar). 13C NMR
1H, J3a,4¼3.4, J3a,3e¼12.5 Hz, H-3a), 2.63 (dd, 1H, J3e,4¼4.6,
J3a,3e¼12.5 Hz, H-3e), 3.69 (dd, 1H, J7,8a¼3.6, J8a,8b¼11.4 Hz, H-8a),
3.75 (s, 3H, OMe), 3.76 (dddd, 1H, J¼12.5, 5.6, 1.1, and 1.5 Hz,
eOCH2), 3.77 (dd, 1H, J5,6¼2.0, J6,7¼7.9 Hz, H-6), 3.82 (dd, 1H,
J7,8b¼1.8, J8a,8b¼11.4 Hz, H-8b), 3.97 (ddd, 1H, J6,7¼7.9, J7,8a¼3.6,
J7,8b¼1.8 Hz, H-7), 4.05 (dddd, 1H, J¼12.5, 1.5, 1.5, and 1.5 Hz,
eOCH2), 4.29 (dd, 1H, J4,5¼7.3, J5,6¼2.0 Hz, H-5), 4.47 (dd, 1H,
J3a,4¼3.4, J3e,4¼4.6, J4,5¼7.3 Hz, H-4), 5.10 (ddd, 1H, J¼17.0, 3.0,
1.4 Hz, CH]CH2), 5.20 (dd,1H, J¼10.5,1.6 Hz, CH]CH2), 5.79 (dddd,
1H, eCH]CH2). 13C NMR (150 MHz, CDCl3):
d 24.1 (CH3), 24.8 (CH3),
(125 MHz, CDCl3):
d
25.11 (Me), 25.09 (Me), 33.2 (C-3), 52.3 (OMe),
31.9 (C-3), 51.4 (OMe), 63.0 (C-8), 70.9 (C-5), 63.2 (OCH2e), 69.1 (C-
4), 68.9 (C-7), 69.7 (C-6), 96.4 (C-2),108.4(Cisop),116.1 (CH2]),132.8
(eCH]), 168.3 (C-1). ESI-HRMS calcd for C15H24O8: 333.1549
[MþH]þ. Found 333.1551.
60.4 (OCH2e), 63.0 (C-8), 69.4 (C-6), 70.2 (C-4), 70.7 (C-7), 71.6 (C-
5), 97.9 (C-2), 109.8 (Cisop) 116.9 (CH2]), 128.36, 128.41, 129.7, 130.0,
133.0, and 133.5 (Ar), 133.2 (eCH]), 165.3 (C]O), 166.2 (C]O),
169.0 (C-1). Anal. Calcd for C26H29O10: C, 64.44; H, 5.97. Found C,
64.56; H, 6.05. Compound 13
b
: 1H NMR (500 MHz, CDCl3):
d
1.21 (s,
4.1.8. Methyl (7,8-di-O-benzoyl-4,5-O-isopropylidene-3-deoxy-
2-octulopyranosylfluoride)onate (16). Methyl 7,8-di-O-benzoyl-4,5-
O-isopropylidene-3-deoxy- -manno-2-octulosonate 12 (717 mg,
D-manno-
3H, Me), 1.51 (s, 3H, Me), 2.17e2.24 (m, 2H, H-3), 3.61 (s, 3H, OMe),
4.05 (dddd, 1H, J¼12.5, 5.5, 1.5, and 1.5 Hz, OCH2), 4.25 (dd, 1H,
J5,6¼2.0, J6,7¼8.0 Hz, H-6), 4.30 (dddd, 1H, J¼12.5, 5.5, 1.5, and
1.5 Hz, OCH2), 4.32 (dd, 1H, J4,5¼7.0, J5,6¼2.0 Hz, H-5), 4.48e4.50 (m,
1H, H-4), 4.77 (dd, 1H, J7,8a¼5.5, J8a,8b¼12.0 Hz, H-8a), 4.92 (dd, 1H,
J7,8b¼2.5, J8a,8b¼12.0 Hz, H-8b), 5.15 (dddd, 1H, J¼10.5, 1.5, 1.5, and
D
1.43 mmol) was treated with (diethylamino)sulfur trifluoride
(DAST, l.9 mL, 14.3 mmol) for 30 min at 0 ꢀC. Dry methanol was
added into the mixture to quench excess DAST, and then the mix-
ture was diluted with dichloromethane and satd NaHCO3. The

5970
T. Ichiyanagi et al. / Tetrahedron 67 (2011) 5964e5971
0
0
0
0
0
organic solution was separated from the mixture and the aqueous
layer was extracted with dichloromethane. The combined organic
layer was dried over anhydrous sodium sulfate, filtered, and con-
centrated. Purification of the residue by silica gel chromatography
(hexane/ethyl acetate¼3/2) gave compound (16) as a mixture of
H-40), 4.59 (dd, 1H, J7 ,8a ¼4.6, J8a ,8b ¼12.5 Hz, H-8a ), 4.61 (dd, 1H,
J3a,4¼11.6, J3e,4¼5.0, J4,5¼2.8 Hz, H-4), 4.69 (dd, 1H, J7,8a¼4.2,
J8a,8b¼12.4 Hz, H-8a), 4.88 (dd, 1H, J7,8b¼2.5, J8a,8b¼12.4 Hz, H-8b),
4.94 (dddd, 1H, J¼17.0, 1.5, 1.5, and 1.5 Hz, CH]CH2), 5.01 (dd, 1H,
0
0
J¼10.5, 1.5, 1.5, and 1.5 Hz, CH]CH2), 5.30 (dd, J7 ,8b ¼2.5,
0
0
0
0
0
0
anomers in 81% yield (581 mg,
a
/b¼3/1). The
a-isomer was able to
J8a ,8b ¼12.5 Hz, H-8b0), 5.68 (ddd, 1H, J6 ,7 ¼7.5, J7 ,8a ¼4.6,
0
0
0
be isolated by recrystallization from ethyl acetate and hexane.
Compound 16
: colorless crystal, mp 117e118 ꢀC, [a 25
ꢁ1.63 (c
1.00, CHCl3), 1H NMR (500 MHz, CDCl3):
J7 ,8b ¼2.5 Hz, H-7 ), 5.65 (m, 1H, eCH]CH2), 5.77 (ddd, 1H, J6,7¼9.1,
J7,8a¼4.2, J7,8b¼2.5 Hz, H-7), 7.34e7.44 (m, 8H, Ar, Ar0), 7.47e7.56 (m,
4H, Ar, Ar0), 7.93e8.08 (m, 8H, Ar, Ar0). 13C NMR (150 MHz, CDCl3):
a
]
D
d
1.24 (s, 3H, Me), 1.43 (s,
3H, Me), 2.08 (ddd, 1H, J3a,4¼3.0, J3a,F¼18.0, J3a,3e¼15.5 Hz, H-3a),
3.04 (ddd, 1H, J3e,4¼4.0, J3e,F¼7.0, J3a,3e¼15.5 Hz, H-3e), 3.83 (s, 3H,
OMe), 4.35 (dd, 1H, J5,6¼2.0, J6,7¼7.5 Hz, H-6), 4.39 (dd, 1H,
J4,5¼7.5 Hz, H-5), 4.58 (ddddd, 1H, J3a,4¼3.0, J3e,4¼4.0, J3a,F¼18.0,
J3e,F¼7.0, J4,5¼7.5 Hz, H-4), 4.69 (dd, 1H, J7,8a¼5.0, J8a,8b¼12.5 Hz, H-
8a), 5.03 (dd, 1H, J7,8b¼2.0, J8a,8b¼12.5 Hz, H-8b), 5.75 (ddd, 1H,
J6,7¼7.5, J7,8a¼5.0, J7,8b¼2.0 Hz, H-7), 7.39e7.44 (m, 4H, Ar),
7.52e7.56 (m, 2H, Ar), 7.99e8.03 (m, 4H, Ar). 13C NMR(125 MHz,
d
24.1 (CH3), 26.7 (CH3), 32.75 (C-30), 32.70 (C-3), 52.6 (OMe), 52.7
(OMe0), 62.8 (C-80), 63.2 (C-8), 65.9 (C-5), 52.6 (OCH2e), 70.1 (C-4),
59.6 (C-7), 69.3 (C-6), 70.4 (C-40), 71.7 (C-60), 70.4 (C-70), 70.8 (C-50),
99.3 (C-20), 99.0 (C-2), 116.1 (CH2]), 128.37, 128.40, 128.43, 128.6,
129.7, 129.8, 133.0, 133.3, 133.7, 165.0, 165.3, 166.0 (Ar, Ar0), 133.3
(eCH]), 165.0, 165.3, 166.0 (C]O), 168.4 (C-1), 169.7 (C-10). Anal.
Calcd for C52H54O19: C, 63.54; H, 5.54. Found C, 63.33; H, 5.58.
Compound 18b d 1.11 (s, 3H, Me), 1.12
: 1H NMR (600 MHz, CDCl3):
CDCl3):
d
24.8 (Me), 25.7 (Me), 31.0 (C-3), 53.1 (COCH3), 62.9 (C-8),
(s, 3H, Me), 2.10 (dd,1H, J3a,4¼3.5, J3a,3e¼15.5 Hz, H-3a), 2.11 (dd,1H,
J3a ,4 ¼not determined, J3a ,3e ¼13.0 Hz, H-3a0), 2.15 (dd, 1H,
0
0
0
0
69.5 (C-4), 70.1 (C-7), 71.1 (C-5), 71.2 (C-6), 107.5 (C-2), 110.0 (Cisop),
128.4, 128.46, 128.51, 129.7, 130.0, and 133.0 (Ar), 165.2 (C]O),
166.0 (C-1), 166.1 (C]O). Anal. Calcd for C26H29O10: C, 62.15; H,
5.42. Found C, 61.85; H, 5.70. Compound 16
NMR (500 MHz, CDCl3): 1.28 (s, 3H, Me), 1.54 (s, 3H, Me), 2.27
J3e ,4 ¼4.0, J3a ,3e ¼13.0 Hz, H-3e0), 2.34 (dd, 1H, J3e,4¼4.0,
J3a,3e¼15.5 Hz, H-3e), 3.60 (s, 3H, OMe’), 3.76 (s, 3H, OMe), 3.92
(dddd, 1H, J¼13.0, 5.0, 1.5, and 1.5 Hz, eOCH2), 4.02 (dddd, 1H,
0
0
0
0
b
: colorless syrup, 1H
0
0
d
J¼13.0, 5.0, 1.5,0 and 1.5 Hz, eOCH2), 4.10 (dd, 1H, J5 ,6 ¼2.5,
0
0
(ddd, 1H, J3a,4¼4.0, J3a,F¼32.5, J3a,3e¼16.0 Hz, H-3a), 2.42 (ddd, 1H,
J3e,4¼2.5, J3e,F¼11.0, J3a,3e¼16.0 Hz, H-3e), 3.69 (s, 3H, OMe), 4.50
(dd, 1H, J4,5¼8.5, J5,6¼1.5 Hz, H-5), 4.20 (dd, 1H, J5,6¼1.5, J6,7¼7.5 Hz,
H-6), 4.66 (ddddd, 1H, J3a,4¼4.0, J3a,F¼32.5, J3e,4¼2.5, J3e,F¼11.0,
J4,5¼8.5 Hz, H-4), 4.75 (dd, 1H, J7,8a¼5.0, J8a,8b¼12.5 Hz, H-8a), 4.90
(dd, 1H, J7,8b¼2.5, J8a,8b¼12.5 Hz, H-8b), 5.69 (ddd, 1H, J6,7¼7.5,
J7,8a¼5.0, J7,8b¼2.5 Hz, H-7), 7.41e7.45 (m, 4H, Ar), 7.53e7.58 (m, 2H,
J6 ,7 ¼8.0 Hz, H-6 ), 4.20 (d, 1H, J4,5¼7.5, J5,6¼1.5 Hz, H-5), 4.21 (dd,
0
0
0
0
0
1H, J4 ,5 ¼7.8, J5 ,6 ¼2.5 Hz, H-5 ), 4.30 (dd, 1H, J5,6¼1.5, J6,7¼9.0 Hz,
0
0
0
0
0
0
H-6), 4.41 (ddd, 1H, J3a ,4 ¼not determined, J3e ,4 ¼4.0, J4 ,5 ¼7.8 Hz,
H-40), 4.49 (dd, 1H, J3a,4¼3.5, J3e,4¼4.0, J4,5¼7.5 Hz, H-4), 4.69 (dd,
0
0
0
0
0
1H, J7 ,8a ¼5.5, J8a ,8b ¼12.5 Hz, H-8a ), 4.74 (dd, 1H, J7,8a¼4.00,
0
0
0
0
J8a,8b¼12.5 Hz, H-8a), 4.81 (dd, J7 ,8b ¼2.5, J8a ,8b ¼12.5 Hz, H-8b ),
4.92 (dd, 1H, J7,8b¼2.5, J8a,8b¼12.5 Hz, H-8b), 4.98 (dddd, 1H, J¼17.0,
1.5, 1.5, and 1.5 Hz, CH]CH2), 5.07 (dddd, 1H, J¼10.5, 1.5, 1.5, and
Ar), 8.00e8.04 (m, 4H, Ar). 13C NMR (125 MHz, CDCl3):
d 24.3 (Me),
0
0
0
0
25.6 (Me), 30.7 (C-3), 53.0 (COCH3), 62.7 (C-8), 68.5 (C-4), 70.7 (C-
7), 70.8 (C-5), 71.5 (C-6), 107.1 (C-2), 110.0 (Cisop), 128.3, 128.4, 129.6,
129.7, 129.9, 133.0, and 133.3 (Ar), 165.2 (C]O), 166.0 (C]O), 167.3
(C-1). Anal. Calcd for C26H29O10: C, 62.15; H, 5.42. Found C, 61.85; H,
5.70.
1.5 Hz, CH]CH2), 5.49 (ddd, 1H, J6’,7’¼8.0, J7 ,8a ¼5.5, J7 ,8b ¼2.5 Hz,
H-70), 5.72 (m, 1H, eCH]CH2), 5.85 (ddd, 1H, J6,7¼9.0, J7,8a¼4.0,
J7,8b¼2.5 Hz, H-7), 7.36e7.44 (m, 8H, Ar, Ar0), 7.49e7.56 (m, 4H, Ar,
Ar0), 8.00e8.08 (m, 8H, Ar, Ar0). 13C NMR (150 MHz, CDCl3):
d 24.7
(CH3), 25.1 (CH3), 32.8 (C-30), 33.3 (C-3), 52.1 (OMe0), 52.2 (OMe),
62.2 (C-80), 63.0 (C-8), 64.0 (C-5), 64.5 (OCH2e), 67.6 (C-4), 69.6 (C-
7), 69.88 (C-6), 69.90 (C-40), 70.2 (C-60), 70.7 (C-70), 72.0 (C-50), 96.7
(C-20), 98.8 (C-2), 116.2 (CH2]), 128.37, 128.41, 128.47, 128.54, 129.4,
129.61, 129.68, 129.71, 129.72, 129.8, 130.0, 130.0, 132.9, 133.0, 133.4,
and 133.5 (Ar, Ar0), 133.1 (eCH]), 165.2, 165.5, 165.9, 166.2 (C]O),
167.6 (C-1), 169.6 (C-10). ESI-HRMS calcd for C52H54O19: 983.3338
[MþH]þ. Found: 983.3335.
4.1.9. Methyl O-[methyl (7,8-di-O-benzoyl-4,5-O-isopropylidene-3-
deoxy-
3-deoxy-
methyl (allyl 7,8-di-O-benzoyl-3-deoxy-
onate 14 (124.0 mg, 0.25 mmol), methyl (7,8-di-O-benzoyl-4,5
-O-isopropylidene-3-deoxy- -manno-2-octulopyranosylfluoride)
onate 16 (248.9 mg, 0.50 mmol), and molecular sieves 5 A
D
-manno-2-octulopyranosyl)onate]-(2e4)-(allyl 7,8-di-O-benzoyl-
-manno-2-octulopyranoside)onate (18). A mixture of
-manno-2-octulopyranoside)-
a-D
a-D
a-D
ꢀ
a
(300.0 mg) was suspended in dichloromethane (8.0 mL). The re-
4.1.10. Methyl O-[methyl (7,8-di-O-benzoyl-3-deoxy-
octulopyranosyl)onate]-(2e8)-(allyl 4,5-O-isopropylidene-3-deoxy-
-manno-2-octulopyranoside)onate (19). A mixture of methyl (allyl
4,5-O-isopropylidene-3-deoxy- -manno-2-octulopyranoside)onate
15 (50.0 mg, 0.15 mmol), methyl (7,8-di-O-benzoyl-4,5-O-iso-
propylidene-3-deoxy- -manno-2-octulopyranosylfluoride)
onate 16 (113 mg, 0.22 mmol), and molecular sieves 5 A
a-D-manno-2-
action mixture was stirred for 1 h and then cooled to ꢁ20 ꢀC.
a-
Triethylamine (69
mL, 0.50 mmol) was added, and boron trifluoride
D
etherate (187
mL, 1.49 mmol) was dropwise to the mixture. After
a-D
stirring for 1.5 h, the reaction was quenched by addition of satd
sodium hydrogen carbonate. The reaction mixture was filtered
through Celite and the filtrate was extracted twice with dichloro-
methane. The combined organic layer was dried over anhydrous
sodium sulfate, filtered, and concentrated. The brownish residue
was purified by silica gel column chromatography (toluene/ethyl
acetate¼2/1) to give compounds 18 as a mixture of anomeric iso-
a-D
ꢀ
a
(150 mg) was suspended in dichloromethane (3.5 mL). The reaction
mixture was stirred for 15 min and then cooled to ꢁ78 ꢀC. Trie-
thylamine (30
etherate (135
mL, 0.22 mmol) was added, and boron trifluoride
mL, 1.1 mmol) was dropwise to the mixture. The re-
mers (175.3 mg, 72%). The
chromatography. -isomer 18
(600 MHz, CDCl3):
a
-linked product was isolated by flash
action temperature was warmed to ꢁ15 ꢀC. After stirring for 1.5 h,
the reaction was quenched by addition of satd sodium hydrogen
carbonate. The reaction mixture was filtered through Celite and the
filtrate was extracted twice with dichloromethane. The combined
organic layer was dried over anhydrous sodium sulfate, filtered, and
concentrated. The brownish residue was purified by gel permeation
chromatography (BioRad S-X3, toluene/ethyl acetate¼3/1) purified
by silica gel column chromatography (toluene/ethyl acetate¼2/1),
silica gel column chromatography (ethyl acetate), and preparative
thin-layer chromatography to give compounds 19 as a colorless
a
a
: [a 25
]
D
þ49.5 (c 1.00, CHCl3), 1H NMR
d
1.20 (s, 3H, Me), 1.38 (s, 3H, Me), 1.93 (dd, 1H,
J3a ,4 ¼2.4, J3a ,3e ¼15.6 Hz, H-3a0), 2.16 (dd, 1H, J3a,4¼11.6,
J3a,3e¼12.6 Hz, H-3a), 2.24 (dd, 1H, J3e,4¼5.0, J3a,3e¼12.6 Hz, H-3e),
0
0
0
0
0
0
0
0
0
2.53 (br, 1H, 5-OH), 2.97 (dd, 1H, J3e ,4 ¼3.6, J3a ,3e ¼15.6 Hz, H-3e ),
3.43 (s, 3H, OMe0), 3.44 (s, 3H, OMe), 3.64 (br s,1H, H-5), 3.84 (dddd,
1H, J¼13.0, 4.9, 1.6, and <0.2 Hz, eOCH2), 3.94 (dddd, 1H, J¼13.0,
5.4, 1.4, and <0.2 Hz, eOCH2), 4.03 (dd, 1H, J5,6¼1.0, J6,7¼9.1 Hz, H-
0
0
0
0
0
0
0
0
6), 4.18 (dd, 1H, J5 ,6 ¼1.8, J6 ,7 ¼7.5 Hz, H-6 ), 4.32 (dd, 1H, J4 ,5 ¼7.8,
J5 ,6 ¼1.8 Hz, H-5 ), 4.51 (ddd, 1H, J3a ,4 ¼2.4, J3e ,4 ¼3.6, J4 ,5 ¼7.8,
syrup (19 mg, 16%). [a 25
]
D
þ32.6 (c 0.96, CHCl3), 1H NMR (600 MHz,
0
0
0
0
0
0
0
0

T. Ichiyanagi et al. / Tetrahedron 67 (2011) 5964e5971
5971
CDCl3):
d
1.15 (s, 3H, Me),1.21 (s, 3H, Me), 1.32 (s, 3H, Me),1.38 (s, 3H,
aqueous 80% trifluoroacetic acid (450 mL) at room temperature. After
Me), 1.76 (dd, 1H, J3a,4¼3.0, J3a,3e¼15.2 Hz, H-3a), 1.93 (dd, 1H,
stirring for 30 min, the solvent was removed by evaporation under an
argon stream to give crude compound, which was not subjected to
further purification. The crude compound was dissolved in methanol
J3a ,4 ¼3.6, J3a ,3e ¼15.0 Hz, H-3a0), 2.61 (dd, 1H, J3e,4¼4.4,
0
0
0
0
0
0
0
0
0
J3a,3e¼15.2 Hz, H-3e), 2.63 (dd, 1H, J3e ,4 ¼5.0, J3a ,3e ¼15.0 Hz, H-3e ),
3.58 (dd, 1H, J7,8a¼3.1, J8a,8b¼10.4 Hz, H-8a), 3.66 (dd, 1H, J7,8b¼not
determined, J8a,8b¼10.4 Hz, H-8b), 3.64 (dddd, 1H, J¼12.5, 5.2, 2.6,
and 1.5 Hz, eOCH2), 3.66 (s, 3H, OMe0), 3.73 (s, 3H, OMe), 3.94 (dddd,
1H, J¼12.5, 5.2, 3.2, and 1.5 Hz, eOCH2), 4.12 (br s, 1H, H-5), 3.33 (dd,
(10 mL), and then 0.1 M sodium hydroxide (679 mL, 0.067 mmol) was
added at room temperature. After stirring for 5 h, the mixture was
concentrated by evaporation. The residue was purified by gel filtration
chromatography (Biogel P-2) to give compound 21 as colorless powder
1H, J5,6¼1.9, J6,7¼8.5 Hz, H-6), 4.17 (dd, 1H, J5 ,6 ¼2.0, J6 ,7 ¼7.4 Hz, H-
in quantitative yield. 1H NMR (500 MHz, D2O):
d
1.68 (dd, 1H, J3a,4¼12.5,
0
0
0
0
60), 4.24 (dd, 1H, J4 ,5 ¼7.0, J5 ,6 ¼2.0 Hz, H-5 ), 4.45 (ddd, 1H,
J3a,3e¼12.5 Hz, H-3a) 1.83 (dd,1H, J3 a,4 ¼12.5 Hz, J3 a,3 e¼12.5, H-30a),1.92
0
0
0
0
0
0
0
0
0
0
J3a ,4 ¼3.6, J3e ,4 ¼5.0,0 J4 ,5 ¼7.0 Hz, H-4 ), 4.67 (dd, 1H, J7 ,8a ¼5.8,
(dd, 1H, J3 e,4 ¼4.0, J3 a,3 e¼12.5 Hz, H-30e), 2.04 (dd, 1H, J3e,4¼4.0,
J3a,3e¼12.5 Hz, H-3e), 3.45e4.06 (m, 13H), 5.13 (d, 1H, J¼11.0 Hz, ]CH2),
5.25 (d, 1H, J¼17.5 Hz, ]CH2), 5.84e5.92 (m, 1H, eCH]). 13C NMR
0
0
0
0
0
0
0
0
0
0
0
0
0
0
J8a ,8b ¼12.3 Hz, H-8a ), 4.37 (dd, 1H, J3a,4¼3.0, J3e,4¼4.4, J4,5¼7.4 Hz,
H-4) 5.08 (ddd,1H, J¼10.6, 2.6,1.6, and 1.5 Hz, CH]CH2), 5.18 (dd,1H,
J¼17.0, 3.2, 1.6, and 1.5 Hz, CH]CH2), 4.92 (dd, 1H, J7 ,8b ¼2.6,
(125 MHz, D2O): d
176.0 (C-10),175.2 (C-1),134.0 (eCH]),117.3 (]CH2),
0
0
J8a ,8b ¼12.3 Hz, H-8b0), 5.68 (ddd, 1H, J6 ,7 ¼7.4, J7 ,8b ¼2.6,
100.1 (C-2), 99.3 (C-20), 72.3 (C-60), 71.5 (C-6), 69.9 (C-70), 69.5 (C-7), 68.6
(C-4), 66.2 (C-50), 65.9 (C-40), 64.21 (C-5), 64.15 (OCH2e), 63.1 (C-8 and
80), 34.5 (C-30), 33.2 (C-3).
0
0
0
0
0
0
0
0
0
J7 ,8a ¼5.8 Hz, H-7 ), 5.75 (dddd, 1H J¼17.0, 10.6, 5.2, 5.2 Hz, eCH]
CH2), 3.92 (ddd, 1H, J6,7¼8.5, J7,8a¼3.1 Hz, J7,8b¼not determined, H-7),
7.34e7.44 (m, 4H, Ar0), 7.47e7.56 (m, 2H, Ar0), 7.93e8.08 (m, 4H, Ar0).
13C NMR (150 MHz, CDCl3): 24.2, 24.3, 23.4, 25.9 (CH3), 31.8 (C-30),
d
Acknowledgements
32.80 (C-3), 51.1 (OMe), 51.7 (OMe0), 61.2 (C-80), 66.0 (C-8), 63.6 (C-5),
64.0 (OCH2e), 66.9 (C-4), 72.5 (C-7), 71.6 (C-6), 68.9 (C-40), 69.7 (C-
60), 70.3 (C-70), 71.0 (C-50), 95.9 (C-20), 97.5 (C-2), 108.2, 108.8, 117.0
(CH2]), 127.32, 127.37, 127.44, 128.65,128.71, 129.1, 131.9, 132.0 (Ar0),
133.1 (eCH]), 164.8, 166.9 (C]O), 168.7 (C-1), 169.5 (C-10). ESI-
HRMS for C41H50O17: 837.2936 [MþNa]þ. Found 837.2933.
This work was supported by Grants-in-Aid for Scientific Re-
search from the Ministry of Education, Culture, Sports, Science, and
Technology of Japanese Government (19780250 and 23580474).
We thank Prof. Junichi Tamura for helpful discussion and are also
grateful to Ms. Yoriko Kaneta for technical assistance.
4.1.11. O-(Sodium 3-deoxy-
sodium (allyl 3-deoxy-
-manno-2-octulopyranoside)onate (20)1416
To a solution of methyl O-[methyl (7,8-di-O-benzoyl-3-deoxy-
manno-2-octulopyranosyl)onate]-(2e8)-(allyl 4,5-O-isopropylidene-
3-deoxy- -manno-2-octulopyranoside)onate 19 (19.0 mg,
23 mol) in dichloromethane (1.0 mL) was added aqueous 80%
trifluoroacetic acid (220
L) at 0 ꢀC. After stirring for 1 h, the solvent
a-D-manno-2-octulopyranosylonate)-(2e8)-
Supplementary data
a-
D
.
a-D-
Supplementary data associated with this article can be found in
the online version, at doi:10.1016/j.tet.2011.06.039. These data in-
clude MOL files and InChIKeys of the most important compounds
described in this article.
a-D
m
m
was removed by evaporation under an argon stream. The residue
was dissolved in methanol (1.0 mL), and then 1.0 M sodium hy-
References and notes
droxide (250 mL, 250 mmol) was added at room temperature. After
1. Yoshizaki, H.; Fukuda, N.; Sato, K.; Oikawa, M.; Fukase, K.; Suda, Y.; Kusumoto, S.
Angew. Chem., Int. Ed. 2001, 40, 1475e1480.
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4. Paulsen, H.; Brenken, M. Liebigs Ann. Chem. 1991, 1113e1126.
5. Kosma, P.; Hofinger, A.; Muller-Loennies, S.; Brade, H. Carbohydr. Res. 2010, 345,
704e708.
6. Sixta, G.; Wimmer, K.; Hofinger, A.; Brade, H.; Kosma, P. Carbohydr. Res. 2009,
344, 1660e1669.
7. Kosma, P.; Schulz, G.; Unger, F. M.; Brade, H. Carbohydr. Res. 1989, 190, 191e201.
8. Ichiyanagi, T.; Sakamoto, N.; Ochi, K.; Yamasaki, R. J. Carbohydr. Chem. 2009, 28,
53e63.
9. Kuboki, A.; Tajimi, T.; Tokuda, Y.; Kato, D. I.; Sugai, T.; Ohira, S. Tetrahedron Lett.
2004, 45, 4545e4548.
10. Middleton, W. J. J. Org. Chem. 1975, 40, 574e578.
11. Posner, G. H.; Haines, S. R. Tetrahedron Lett. 1985, 26, 5e8.
12. Imoto, M.; Kusunose, N.; Matsuura, Y.; Kusumoto, S.; Shiba, T. Tetrahedron Lett.
1987, 28, 6277e6280.
13. Oikawa, M. Trends Glycosci. Glycotechnol. 2002, 14, 115e125.
14. Bock, K.; Thomsen, J. U.; Kosma, P.; Christian, R.; Holst, O.; Brade, H. Carbohydr.
Res. 1992, 229, 213e224.
15. Kosma, P.; Gass, J.; Schulz, G.; Christian, R.; Unger, F. M. Carbohydr. Res. 1987, 167,
39e54.
stirring for 8 h, the mixture was concentrated under argon gas. The
residue was purified by gel filtration chromatography (Biogel P-2)
to give compound 20 as colorless powder (8.1 mg, 65%). 1H NMR
(600 MHz, D2O):
d
1.71 (dd, 1H, J3a,4¼12.5, J3a,3e¼12.5 Hz, H-3a) 1.71
(dd, 1H, J3 a,4 ¼12.5 Hz, J3 a,3 e¼12.5, H-30a), 1.94 (dd, 1H, J3 e,4 ¼4.0,
0
0
0
0
0
0
J3 a,3 e¼12.5 Hz, H-30e), 1.96 (dd, 1H, J3e,4¼4.0, J3a,3e¼12.5 Hz, H-3e),
3.47e3.58 (m, 3H), 3.78e3.97 (m, 5H), 5.16 (d,1H, J¼11.0 Hz, ]CH2),
5.26 (d, 1H, J¼17.5 Hz, ]CH2), 5.84e5.91 (m, 1H, eCH]). 13C NMR
0
0
(125 MHz, D2O): d
175.9 (C-10), 175.3 (C-1), 133.8 (eCH]), 117.5 (]
CH2), 100.6 (C-2),100.1 (C-20), 71.7 (C-60), 71.3 (C-6), 69.3 (C-70), 67.7
(C-7), 66.3 (C-5), 66.2 (C-50), 66.03 (C-4), 65.95 (C-40), 64.9 (C-8)
64.3 (OCH2e), 63.1 (C-80), 34.1 (C-30), 33.9 (C-3).
4.1.12. O-(Sodium 3-deoxy-
sodium (allyl 3-deoxy-
-manno-2-octulopyranoside)onate (21)15. To
solution of methyl O-[methyl (7,8-di-O-benzoyl-4,5-O-iso-
propylidene- 3-deoxy- -manno-2-octulopyranosyl)onate]-(2e4)-
(allyl 7,8-di-O-benzoyl-3-deoxy- -manno-2-octulopyranoside)onate
18 (10.0 mg, 0.01 mmol) in dichloromethane (3.0 mL) was added
a-D-manno-2-octulopyranosylonate)-(2e4)-
a-D
a
a-D
a-D
16. Sokolowski, T.; Haselhorst, T.; Scheffler, K.; Weisemann, R.; Kosma, P.; Brade, H.;
Brade, L.; Peters, T. J. Biomol. NMR 1998, 12, 123e133.
a