Chemical synthesis of β-d-psicofuranosyl disaccharides

Article abstract of DOI:10.1016/j.carres.2010.05.030

Disaccharides composed of a β-d-psicofuranosyl unit were prepared by the glycosylation reaction of monosaccharide acceptors including three 2,3,4,6-tetra-O-protected hexopyranoses with a d-psicofuranosyl benzyl phthalate derivative (4). A β-d-psicofuranosidic bond was formed by the TMSOTf-promoted reaction with high selectivity. Removal of the O-protecting groups from the resulting α-d-hexopyranosyl β-d-psicofuranosides furnished the first chemical synthesis of α-d-gluco-, α-d-galacto-, and α-d-mannopyranosyl β-d-psicofuranosides. The common β-d-psicofuranosyl donor 4 was derived efficiently from d-psicose in five steps.

Full text of DOI:10.1016/j.carres.2010.05.030

Carbohydrate Research 345 (2010) 1722–1729
Contents lists available at ScienceDirect
Carbohydrate Research
journal homepage: www.elsevier.com/locate/carres
Chemical synthesis of b-D-psicofuranosyl disaccharides
*
Atsushi Ueda, Takanori Yamashita, Jun’ichi Uenishi
Kyoto Pharmaceutical University, Misasagi, Yamashina, Kyoto 607-8412, Japan
a r t i c l e i n f o
a b s t r a c t
Article history:
Received 7 May 2010
Received in revised form 27 May 2010
Accepted 31 May 2010
Available online 4 June 2010
Disaccharides composed of a b-
monosaccharide acceptors including three 2,3,4,6-tetra-O-protected hexopyranoses with a
anosyl benzyl phthalate derivative (4). A b-
D
-psicofuranosyl unit were prepared by the glycosylation reaction of
-psicofur-
-psicofuranosidic bond was formed by the TMSOTf-promoted
reaction with high selectivity. Removal of the O-protecting groups from the resulting -hexopyranosyl
b- -psicofuranosides furnished the first chemical synthesis of -gluco-, -galacto-, and -manno-
pyranosyl b-
-psicose in five steps.
D
D
a-D
D
a
-D
a-
D
a-D
D
-psicofuranosides. The common b-
D
-psicofuranosyl donor 4 was derived efficiently from
Keywords:
Psicose
Psicofuranosyl disaccharide
Non-reducing disaccharide
Glycosylation
D
Ó 2010 Elsevier Ltd. All rights reserved.
Psicofuranosyl donor
1. Introduction
case of D
-psicofuranosyl donor 4 with O-glycosyl acceptors9,10
including primary and secondary alcohols, phenols, and aminoal-
cohols. An example with ceramide is illustrated in Scheme 1. The
high b-selectivity appears to arise from the steric influence of the
acetonide in 4. Thus, one of the two methyl groups blocks the at-
D
-Psicose (Fig. 1) and
chiral center on the furanose ring. Although
nent of (+)-sucrose and is widely found in fruits,
in nature only rarely.1 Therefore, the chemistry and biology of
psicose have not been extensively investigated in recent decades.
Because -psicose has recently been prepared in large amounts
by biotransformation from
-fructose,2 as well as by chemical
transformation,3,4 biological investigations of
-psicose have grad-
ually increased.5 These studies have revealed novel properties of
psicose such as suppression of postprandial blood glucose eleva-
tion,5a–c -glucosidase inhibitory activity,5d antioxidant,5e neuro-
protective effect,5f prevention of arteriosclerosis,5g and diet
sugar.5h However, except for the enzymatic production of
-glu-
copyranosyl b-
-psicofuranoside (1),6 no oligosaccharides contain-
ing -psicofuranosides have been reported. Herein, we report the
synthesis of b- -psicofuranosyl saccharides including non-reduc-
D
-fructose are diastereoisomers at the C-3
-fructose is a compo-
-psicose appears
D
D
D
-
tack of the glycosyl acceptor from a-side and results selectively
in b-glycosylation.11
D
Yamanoi et al. has recently reported that in the Sc(OTf)3-pro-
moted glycosidation of 2-O-acetyl-1,3,4,6-tetra-O-benzoyl-D-psi-
D
D
OH
D
-
O
HO
HO
a
OH
HO
O
HO
O
HO
a
-D
O
OH
D
HO
OH
OH
D
HO
OH
D
D-Psicose
ing disaccharides 1–3 via b-selective O-glycosylation using
cofuranose derivative 4 as the glycosyl donor.
D-psi-
1
OH
HO
HO HO
2. Results and discussion
O
O
HO
HO
HO
HO
Although N- and C-glycosidation reactions of
D-psicose have
O
O
HO
HO
been reported,7,8 these reactions showed variable stereoselectivi-
ties depending on both the N- and C-glycosyl acceptors. However,
we have found excellent b-selectivity and chemical yield in the
O
O
OH
OH
HO
OH
HO
OH
3
2
* Corresponding author. Tel.: +81 75 595 4665; fax: +81 75 595 4763.
E-mail address: juenishi@mb.kyoto-phu.ac.jp (J. Uenishi).
Figure 1. D-Psicose and b-D-psicofuranosyl disaccharides 1–3.
0008-6215/$ - see front matter Ó 2010 Elsevier Ltd. All rights reserved.
doi:10.1016/j.carres.2010.05.030

A. Ueda et al. / Carbohydrate Research 345 (2010) 1722–1729
1723
O
O
COOBn
HN
O
BzO
BzO
O
O
TMSOTf
O
ceramide
OBz
OBz
CH2Cl2
—40 ºC
O
O
OBz
O
O
75%
4
Scheme 1. TMSOTf-promoted glycosylation of ceramide with donor 4.10
cofuranose with 2,3,4,6-tetra-O-benzyl-
D
-glucopyranose, four dia-
20:8:28:44
saccharide
stereomeric 2,10-disaccharides were formed in
a
O
BzO
TMSOTf
CH2Cl2
ratio.12 Because donor 4 appears to be suitable for stereoselective
O-psicofuranosylation reactions, we considered that this glycosyl-
ation reaction could be a good synthetic approach to provide vari-
ous disaccharides including non-reducing disaccharides. The donor
acceptors
O
4
9 13
—
OBz
14—18
disaccharides
O
O
4 was prepared from
D
-ribose in nine steps as described in our pre-
vious paper.9 As
D
-psicose is sufficiently available from
D-fructose
due to the efficient improvements in enzymatic transformation
OH
O
technology,2 we have exploited an alternative synthesis of 4 from
OBn
O
O
BnO
O
HO
D
-psicose (Scheme 2).
First, ditritylation of
BnO
BnO
BnO
O
D
-psicose with an excess of trityl chloride
BnO
O
OMe
in pyridine proceeded smoothly to give triol 5 in 88% yield. Protec-
tion of the C-3 and C-4 hydroxy groups of 5 with 2,2-dimethoxy-
propane in the presence of PPTS gave the corresponding
acetonide 6 in 89% yield. Removal of the two O-trityl groups under
Birch conditions and the successive benzoylation of the resulting
BnO
O
OH
10
9
11
OBn
O
two hydroxy groups with benzoyl chloride gave
D-psicofuranose
BnO
BnO
BnO
BnO
BnO
8 in 54% overall yield in four steps from -psicose. The conversion
D
O
of 8 to 4 was performed by the dicyclohexylcarbodiimide-medi-
ated condensation with benzyl hydrogen phthalate13 in 95% yield.9
Psicosyl donor 4 was subjected to glycosidation with five mono-
saccharides 9–13 (Scheme 3). The reactions were conducted in
dichloromethane in the presence of TMSOTf at ꢀ40 to ꢀ20 °C.
The results are shown in Table 1. The reaction with 1,2:3,4-di-O-
BnO
BnO
12
OH
OH
13
Scheme 3. TMSOTf-promoted glycosylation of acceptors 9–13 with donor 4.
isopropylidene-a-D-galactopyranose (9) possessing a primary
hydroxy group at the C-6 position proceeded smoothly to give
b-glycoside 14 exclusively in 94% yield (entry 1). Acceptor 1014
was less reactive and required longer reaction time than 9 due to
the sterical reason, but gave 15 in 57% yield with exclusive b-selec-
tivity (entry 2).
For the stereocontrolled synthesis of non-reducing disaccha-
rides, assembling two saccharides at the anomeric centers by gly-
cosylation reaction is generally quite a difficult task,15,16 compared
to other standard glycosylation reactions, because both glycosylat-
ing positions are anomeric centers and may be isomerized during
the reaction. Nonetheless, this direct glycosylation is straightfor-
ward for the synthesis of a non-reducing disaccharide. To over-
come this problem, several synthetic efforts such as neighboring
OH
OH
HO
TrO
OTr
OH
O
O
a
group participation,17 the use of an
a-side protected glycosyl do-
HO
OH
HO
OH
nor,18 and using an exo-glycal donor for the synthesis of trehalose
type disaccharides19 have been reported. Keeping this in mind, a
5
D-Psicose
glycosylation approach using 4 for the synthesis of b-D-psicofur-
anosyl non-reducing disaccharides would be promising. In fact,
the reaction of 4 with O-benzyl-protected hexopyranose acceptors
OH
OR
RO
11–13 gave b-
of the expectation of an anomeric effect for these compounds, a
mixture of - and b- -hexopyranosides was obtained. For example,
glycosylation of 11 ( -isomer only) with 4 provided 26% of the
bb-isomer 16bb and 58% of b-isomer 16 b (entry 3). The reaction
of galactose acceptor 12 ( :b isomer ratio, 4:3) with 4 gave 17
and 17bb in 33% and 41% yields, respectively (entry 4), while that
of mannose acceptor 13 ( :b isomer ratio, 9:2) afforded 18
D-psicofuranosides exclusively (entries 3–5). In spite
O
b
e
a
D
4
O
O
a
a
a
a
ab
6
:
R = Tr
R = H
R = Bz
c
d
7
:
8:
a
ab
and 18bb in 27% and 39% yields, respectively (entry 5). These re-
sults indicate that the anomeric stereocontrol for psicosides is sat-
isfactory, although that for hexopyranoside is unsatisfactory, due
to an epimerization of the anomeric center even when an excess
Scheme 2. Conversion of
conditions: (a) TrCl, DMAP, pyridine, 50 °C, 8 h, 88%; (b) PPTS, 2,2-dimethoxypro-
pane, 50 °C, 5 h, 89% ( :b = 1:2); (c) Na–NH3, THF, ꢀ78 °C, 10 min, 76% ( :b = 1:3);
(d) BzCl, pyridine, 0 °C, 30 min, 87% ( :b = 1:3); (e) benzyl hydrogen phthalate, DCC,
DMAP, CH2Cl2, rt, 20 h, 95% (
:b = 6:94).9
D-psicose into D-psicofuranosyl donor 4. Reagents and
a
a
a
a
of a-isomers were used.

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A. Ueda et al. / Carbohydrate Research 345 (2010) 1722–1729
Table 1
Glycosidation of D-psicofuranosyl donor 4 with D-hexopyranose acceptors
Entry
Glycosyl acceptor
Temp (°C)
Time (min)
Product (yield, %)
Structure
O
O
BzO
O
O
O
O
1
9
ꢀ40
50
14 (94%)
OBz
O
O
O
O
O
O
BnO
O
O
BzO
BnO
BnO
2
10
ꢀ40 to ꢀ20
120
15 (57%)
OMe
OBz
OBn
O
OBn
O
BnO
BnO
BnO
BnO
BzO
O
BnO
BnO
O
16
ab (58%)
BzO
BzO
BzO
3a
11
ꢀ40 to ꢀ20
30
O
O
16bb (26%)
OBz
OBz
O
O
O
O
16αβ
16ββ
OBn
O
OBn
O
BnO
BnO
BnO
BnO
O
BnO
BnO
O
O
BzO
17
ab (33%)
4
12
ꢀ40 to ꢀ20
20
O
17bb (41%)
OBz
OBz
O
O
O
O
17ββ
17αβ
BnO
BnO
BnO
BnO
BnO
BnO
BnO
BzO
O
BnO
O
O
O
18ab (27%)
18bb (39%)
O
O
5
13
ꢀ40 to ꢀ20
30
O
OBz
OBz
O
O
O
18ββ
18αβ
a
See Ref. 9.
Table 2
The stereochemistry of 16 was determined by the conversion of
the less polar isomer 16
b to (+)-sucrose.9 The structures of 17 and
Chemical shifts and coupling constants of the H-10 proton for 16–24
a
18 were determined by 1H NMR spectroscopy. NOE studies on
these compounds clearly indicated that the glycosidic bond of psi-
coside was assigned as b. Thus, NOE relations were observed be-
tween the H-1 proton and the endo Me group of the acetonide,
as well as H-5 proton and the same Me group in each of the iso-
mers 17 and 18. Stereochemistry of gluco- and galacto-type hexo-
pyranoses is assigned by a coupling constant of the anomeric
proton. The values of chemical shift and vicinal coupling constant
of the H-10 proton for the pyranose unit of disaccharides 16–24
Entry
Compound
16
ba
16bba
17
ba
17bba
18
ba
Chemical shift (ppm)
J-value (Hz)
1
2
3
4
5
6
7
8
9
a
5.42
5.14
5.44
5.09
5.77
4.94
5.52
5.60
5.48
5.39
5.32
5.56
3.5
7.3
br s
7.7
2.0
br s
3.5
3.7
1.3
3.7
3.7
2.0
a
a
18bba
19b
20b
21b
22c
10
11
12
are listed in Table 2. It is obvious that
17
a-pyranosides 16ab and
b possess smaller coupling constants (ꢁ3.5 Hz) than those of
23c
24c
a
16bb and 17bb (ꢁ7.3 Hz). However, it is difficult to determine an
a
b
c
In C6D6.
In CDCl3.
In CD3OD.
anomeric structure for the mannopyranosides. Indeed, the vicinal
coupling constants of the anomeric protons of 18ab and 18bb
showed similar J-values (2.0 Hz vs br s). However, the NOE exper-
iment was effective in determining the structures. The more polar
isomer 18bb indicated clear NOE relationships between the ano-
meric proton H-10 and the three protons H-20, H-30, and H-50
(Fig. 2). On the other hand, no NOE relationship was observed
between the anomeric proton H-10 and the two protons H-30 and
H-50 in the less polar isomer, which was identical to the 18
ab
isomer.

A. Ueda et al. / Carbohydrate Research 345 (2010) 1722–1729
1725
R
OBn
R4
O
BzO
R2
O
R3
O
O
16αβ
BnO
H5
a
b
OBz
R1
O
O
O
H1
17αβ
BzO
H1
Me
18αβ
Me
OBz
: noesy
HO
OH
β-D-psicofuranoside
1
3
2
4
19:
20:
R = R = OBn, R = R = H
1
4
2
3
OBn
OBn
R = R = OBn, R = R = H
H4'
H4'
21: R2 = R3 = OBn, R1 = R4 = H
OBn
O
OBn
O
H1'
BnO
BnO
BnO
BnO
O
OBn
R4
H2'
β-Psif
5' H2'
R2
H5'
H3'
H
H1'
R3
BnO
H3'
O
O
1
c
R1
β-Psif
O
HO
2
3
18αβ
18ββ
O
OH
Figure 2. NOESY experiments for b-
ranosides 18.
D-psicofuranosyl disaccharides and mannopy-
HO
OH
1
3
2
4
22:
23:
R = R = OBn, R = R = H
Completion of the synthesis for b-
ing disaccharides was achieved in three-step sequence of different
deprotection procedures (Scheme 4). First, disaccharides 16 b,
17 b, and 18 b were treated with p-toluenesulfonic acid in MeOH
D-psicofuranosyl non-reduc-
1
4
2
3
R = R = OBn, R = R = H
24: R2 = R3 = OBn, R1 = R4 = H
a
a
a
to give diols 19,9 20, and 21 in 68%, 61%, and 63% yields, respec-
tively. Exposure of diols 19, 20, and 21 to methanolic potassium
carbonate resulted in debenzoylation to provide tetraols 22, 23,
and 24 with excellent yields. After successive deprotection of the
benzyl groups by hydrogenation in the presence of Pearlman’s cat-
alyst, non-reducing disaccharides 1, 2, and 3 were obtained in
quantitative yields. Because disaccharides 1–3 are diastereomeric
isomers of (+)-sucrose, we will examine them for biological prop-
erties such as sweet taste and inhibitory activity against a-glycosi-
dases. In fact, in initial qualitative experiments, these compounds
exhibited a sweet taste.
In conclusion, we have accomplished the first chemical synthe-
sis of non-reducing disaccharides 1–3. b-Selective D-psicofuranosy-
lation of saccharide acceptors 9–13 with donor 4 was carried out in
CH2Cl2 using TMSOTf as a promoter of the glycosylation reaction.
Scheme 4. Synthesis of disaccharides 1–3. Reagents and conditions: (a) p-TsOH,
MeOH, rt, 45 h; (b) K2CO3, MeOH, rt, 1 h; (c) H2, Pd(OH)2–C, MeOH, rt, overnight.
for flash chromatography. Analytical thin-layer chromatography
(TLC) was performed on glass pre-coated with silica gel (0.25 mm
thickness). Compounds were observed in UV-light at 254 nm and
then visualized with p-anisaldehyde/sulfuric acid in EtOH stain or
molybdatephosphoric acid in EtOH stain. High performance liquid
chromatography (HPLC) was carried out on a UV spectrophotomet-
ric detector (254 nm) to which a 20 ꢂ 250 mm size column packed
with silica gel was attached or an RI spectrophotometric detector
to which a 10 ꢂ 200 mm size Chemco pakÒ (Kromasol 5NH2) col-
umn. All moisture-sensitive reactions were carried out under an ar-
gon atmosphere. THF was dried over sodium/benzophenone ketyl,
and CH2Cl2 was dried over P2O5, and they were distilled prior to use.
b-Psicofuranosyl donor 4 was derived from
D-psicose in five steps
in excellent yield. The synthetic pathway described in this paper
provides short access to b-D-psicofuranosyl saccharides including
non-reducing disaccharide.
3.2. 1,6-Di-O-trityl-
A mixture of
a
-
D
-psicofuranose (5)
D-psicose (100 mg, 0.56 mmol), 4-(dimethyl-
amino)pyridine (34 mg, 0.28 mmol), and trityl chloride (772 mg,
2.78 mmol) in pyridine (4 mL) was heated at 50 °C for 8 h. The
reaction was quenched with water (20 mL) and the reaction mix-
ture was extracted with CHCl3 (15 mL ꢂ 3). The combined organic
extracts were washed with water (10 mL) and dried over MgSO4,
and the solvent was evaporated under reduced pressure. The resid-
ual oil was purified by flash column chromatography on silica gel
eluted with 30% EtOAc in hexane to give 5 (322 mg) in 88% yield.
Colorless oil. Rf = 0.21 (40% EtOAc in hexane). 1H NMR (300 MHz,
CDCl3) d: 7.45–7.18 (30H, m), 4.21 (1H, ddd, J5,6b = 4.1, J5,6a = 3.7,
J4,5 = 3.3 Hz, H-5), 4.09 (1H, ddd, J4,OH = 5.9, J3,4 = 5.7, J4,5 = 3.3 Hz,
H-4), 4.03 (1H, s, 2-OH), 4.02 (1H, d, J3,OH = 7.0, J3,4 = 5.7 Hz, H-3),
3.35 (1H, d, J1a,1b = 9.5 Hz, H-1a), 3.31 (1H, dd, J6a,6b = 10.1,
J5,6a = 3.7 Hz, H-6a), 3.29 (1H, d, J1a,1b = 9.5 Hz, H-1b), 3.21 (1H,
dd, J6a,6b = 10.1, J5,6b = 4.1 Hz, H-6b), 2.92 (1H, d, J4,OH = 7.0 Hz, 4-
OH), 2.67 (1H, d, J3,OH = 5.9 Hz, 3-OH). 13C NMR (75 MHz, CDCl3)
d: 143.6, 143.4, 128.6, 127.9, 127.8, 127.1, 127.0, 102.7, 87.0,
86.8, 82.7, 72.4 (2C), 66.3, 63.9. IR (film): 3443, 3058, 1730, 1489,
1447, 1078, 748, 701 cmꢀ1. MS (FAB) m/z: 687 [M+Na]+. HRMS
(FAB) m/z: calcd for C44H40O6Na, 687.2723; found, 687.2726.
3. Experimental
3.1. General methods
Melting points were taken on a Yanaco micromelting apparatus
and were uncorrected. Specific rotations were measured on a JASCO
P-2200 polarimeter using CHCl3, MeOH, or H2O as a solvent. 1H NMR
and 13C NMR spectra were measured on JEOL JNM-AL-300 (300 MHz
and 75 MHz) or Varian UNITY INOVA 400 NB (400 MHz and
100 MHz) spectrometer. Chemical shifts (d) are reported in parts
per million (ppm) relative to the resonance of the solvent or to tet-
ramethylsilane (0.00 ppm) for 1H NMR spectra and ppm relative to
the resonance of the solvent or to acetonitrile (1.47 ppm) when
D2O was used, for 13C NMR spectra. For the assignment of protons
in 1H NMR spectra, protons of pyranoside ring are numbered as 10,
20, etc. IR spectra were recorded on a JASCO FT/IR-410 spectropho-
tometer. Low- and high-resolution mass spectra (LRMS and HRMS)
were obtained on a JEOL JMS 303HF spectrometer using fast atom
bombardment (FAB) ionization. Silica gel (230–400 mesh) was used

1726
A. Ueda et al. / Carbohydrate Research 345 (2010) 1722–1729
3.3. 3,4-O-Isopropylidene-1,6-di-O-trityl-
D
-psicofuranose (6)
at the same temperature. Then, MeOH (0.5 mL) was added and
the mixture was further stirred for 20 min. Water was added and
the mixture was extracted with EtOAc (15 mL ꢂ 2). The organic ex-
tract was washed with water and brine (10 mL each), dried over
MgSO4 and evaporated. The crude product was purified by flash
column chromatography on silica gel eluted with 25% EtOAc in
A mixture of 5 (129 mg, 0.19 mmol) and pyridinium p-toluene-
sulfonate (146 mg, 0.58 mmol) in 2,2-dimethoxypropane (2 mL)
was heated at 50 °C for 5 h. Satd aq NaHCO3 (4 mL) was added to
the reaction mixture and extracted with EtOAc (2 ꢂ 20 mL). The or-
ganic layer was washed with water, brine (10 mL each), and dried
over MgSO4. Solvent was removed and the residual oil was purified
by flash chromatography on silica gel eluted with 10% EtOAc in
hexane to give 8 (71 mg) in 87% yield as a 1:3 mixture of
a- and
b-anomers. Colorless oil. Spectral data fully matched with the data
reported previously.9
hexane to give 6 (119 mg) in 89% yield as a 1:2 mixture of
a-
and b-isomers. Colorless oil. Rf = 0.25 (10% EtOAc in hexane). 1H
NMR (300 MHz, CDCl3) d (b-anomer): 7.49–7.40 (12H, m), 7.31–
7.18 (18H, m), 4.63 (1H, dd, J3,4 = 5.9, J4,5 = 1.3 Hz, H-4), 4.42 (1H,
d, J3,4 = 5.9 Hz, H-3), 4.34 (1H, ddd, J5,6b = 7.3, J5,6a = 5.9,
J4,5 = 1.3 Hz, H-5), 4.16 (1H, s, OH), 3.41 (1H, dd, J6a,6b = 9.5,
J5,6a = 5.9 Hz, H-6a), 3.37–3.30 (2H, m, H-1a, 1b), 3.22 (1H, dd,
3.6. General procedure for the psicofuranosylation of
compounds 9–13
A mixture of glycosyl donor 4 (1 mmol, a:b = 6:94) and glycosyl
acceptor 9–13 (1.2–1.5 mmol) was predried azeotropically by
coevaporation with dry toluene (10 mL ꢂ 3), which was further
dried under reduced pressure over the presence of P4O10. The dried
mixture was dissolved in dry CH2Cl2 (20 mL), to which was added
TMSOTf (1.5 mmol) at ꢀ40 °C. The reaction was continued under
the conditions indicated in Table 1. Satd aq NaHCO3 (10 mL) and
CH2Cl2 (20 mL) were added to the reaction mixture, and organic
layer was washed with water and brine, dried (Na2SO4), and evap-
orated under reduced pressure. The residue was purified by flash
chromatography on silica gel eluted with 15% of EtOAc in hexane
for 14–18, respectively. Separation of anomers for 17 and 18 were
performed by HPLC under the following conditions; 17, eluent, 10%
EtOAc in hexane, flow rate, 10 mL/min, retention time, 31.3 min
J6a,6b = 9.5, J5,6b = 7.3 Hz, H-6b), 1.31 (3H, s), 1.25 (3H, s); d (a-ano-
mer): 7.49–7.40 (12H, m), 7.31–7.18 (18H, m), 4.60–4.53 (2H, m,
H-3, 4), 4.35–4.30 (1H, m, H-5), 3.33–3.18 (2H, m, H-6a, 6b), 3.27
(1H, d, J1a,1b = 9.5 Hz, H-1a), 3.18 (1H, d, J1a,1b = 9.5 Hz, H-1b),
1.60 (3H, s), 1.36 (3H, s). 13C NMR (75 MHz, CDCl3) d (b-anomer):
143.8, 143.5, 128.7–126.9 (Ar), 112.4, 106.0, 85.7, 85.3, 82.8,
81.7, 81.3, 65.1, 65.0, 26.4, 25.4; d (a-anomer): 143.8, 143.7,
128.7–126.9 (Ar), 115.5, 102.2, 87.0, 86.8, 86.6, 86.6, 81.3, 66.5,
63.9, 26.5, 25.2. IR (film): 3444, 1490, 1448, 1215, 1075, 754,
703 cmꢀ1. MS (FAB) m/z: 727 [M+Na]+. HRMS (FAB) m/z: calcd
for C47H44O6Na, 727.3036; found, 727.3042.
(17ab), and 35.3 min (17bb); 18, eluent, 20% EtOAc in hexane, flow
3.4. 3,4-O-Isopropylidene-
D-psicofuranose (7)
rate, 15 mL/min, retention time, 11.8 min (18ab), and 13.5 min
(18bb). Chemical yields are indicated in Table 1 and physical and
To a dark blue solution of sodium (ca. 30 mg) in liquid ammonia
(5 mL) was added dropwise a solution of compound 6 (84.4 mg,
0.120 mmol) in THF (1 mL) at ꢀ78 °C. The mixture was stirred vig-
orously for 10 min at the same temperature, and then the reaction
was carefully quenched by the addition of powdered NH4Cl
(300 mg). After disappearance of dark blue color, MeOH (3 mL)
was added and the reaction was allowed to warm up to room tem-
perature to evaporate solvents. EtOAc (20 mL) was added to the
residual white solid and the whole was filtered through 1 cm of sil-
ica gel pad. The filtrate was concentrated under vacuum. The resi-
due was purified by silica gel flash chromatography eluted with
80% EtOAc in hexane to give triol 7 (20 mg) in 76% yield as a 1:3
spectroscopic data are following.
3.6.1. 6-O-(1,6-Di-O-benzoyl-3,4-O-isopropylidene-b-
D
-psicofur-
anosyl)-1,2:3,4-di-O-isopropylidene-a-D-galactopyranose (14)
Colorless oil. Rf = 0.42 (30% EtOAc in hexane). ½a D23
ꢀ37.4 (c 1.0,
ꢃ
CHCl3). 1H NMR (300 MHz, CDCl3) d: 8.09–8.06 (4H, m), 7.60–7.52
(2H, m), 7.48–7.39 (4H, m), 5.42 (1H, d, J1 ,2 = 5.0 Hz, H-10), 4.83
(1H, dd, J3,4 = 5.9, J4,5 = 1.1 Hz, H-4), 4.76 (1H, d, J3,4 = 5.9 Hz, H-3),
4.69 (1H, d, J1a,1b = 11.9 Hz, H-1a), 4.57–4.50 (3H, m, H-40, 5, 6a),
4.53 (1H, d, J1a,1b = 11.9 Hz, H-1b), 4.41 (1H, dd, J6a,6b = 13.4,
0
0
J5,6b = 9.9 Hz, H-6b), 4.24 (1H, dd, J1 ,2 = 5.0, J2 ,3 = 2.4 Hz, H-20),
0
0
0
0
4.21 (1H, dd, J3 ,4 = 7.9, J4 ,5 = 1.8 Hz, H-40), 3.88 (1H, td, J5 ,6 = 6.6,
0
0
0
0
0
0
J4 ,5 = 1.8 Hz, H-50), 3.76 (2H, d, J5 ,6 = 6.6 Hz, H-60), 1.51 (3H, s),
1.37 (3H, s), 1.33 (3H, s), 1.33 (3H, s), 1.28 (3H, s), 1.26 (3H, s).
13C NMR (75 MHz, CDCl3) d: 165.9, 165.7, 133.1, 132.8, 130.0,
129.8, 129.6, 128.3, 128.1, 113.2, 109.3, 109.2, 108.4, 96.1, 85.3,
84.4, 82.3,70.7, 70.4, 70.4, 66.5, 65.0, 60.5, 60.0, 26.5, 25.8, 25.7,
25.1, 24.8, 24.3. IR (KBr): 2987, 1725, 1452, 1381, 1273, 1212,
1071, 870, 711 cmꢀ1. MS (FAB) m/z: 693 [M+Na]+. HRMS (FAB)
m/z: calcd for C35H42O13Na, 693.2523; found, 693.2528.
0
0
0
0
mixture of a- and b-isomers. Colorless syrup. Rf = 0.21 (80% EtOAc
in hexane). 1H NMR (300 MHz, CDCl3) d (b-anomer): 4.85 (1H, dd,
J3,4 = 5.9, J4,5 = 0.9 Hz, H-4), 4.60 (1H, d, J3,4 = 5.9 Hz, H-3), 4.33 (1H,
ddd, J5,6b = 4.2, J5,6a = 2.9, J4,5 = 0.9 Hz, H-5), 3.81 (1H, d,
J1a,1b = 12.3 Hz, H-1a), 3.78 (1H, d, J1a,1b = 12.3 Hz, H-1b), 3.74
(1H, dd, J6a,6b = 12.3, J5,6a = 2.9 Hz, H-6a), 3.70 (1H, dd,
J6a,6b = 12.3, J5,6b = 4.2 Hz, H-6b), 1.48 (3H, s), 1.31 (3H, s); d (a-ano-
mer): 4.79 (1H, dd, J3,4 = 7.0, J4,5 = 3.8 Hz, H-4), 4.74 (1H, d,
J3,4 = 7.0 Hz, H-3), 4.24 (1H, ddd, J4,5 = 3.8, J5,6b = 3.3, J5,6a = 2.7 Hz,
H-5), 3.85 (1H, dd, J6a,6b = 12.2, J5,6a = 2.7 Hz, H-6a), 3.70 (1H, d,
J1a,1b = 11.5 Hz, H-1a), 3.68 (1H, dd, J6a,6b = 12.2, J5,6b = 3.3 Hz, H-
6b), 3.59 (1H, d, J1a,1b = 11.5 Hz, H-1b), 1.60 (3H, s), 1.40 (3H, s).
13C NMR (75 MHz, CDCl3) d (b-anomer): 112.7, 106.2, 86.6, 86.1,
3.6.2. Methyl 4-O-(1,6-di-O-benzoyl-3,4-O-isopropylidene-b-D-
psicofuranosyl)-2,3,6-tri-O-benzyl-a-D-glucopyranoside (15)
Colorless oil. Rf = 0.42 (30% EtOAc in hexane). ½a D22
ꢃ
+28.3 (c 1.0,
CHCl3). 1H NMR (300 MHz, C6D6) d: 8.34–8.30 (2H, m), 8.19–8.16
(2H, m), 7.45–7.42 (2H, m), 7.29–6.89 (19H, m), 5.41 (1H, d,
J = 7.0 Hz), 5.33 (1H, d, J1a,1b = 12.1 Hz, H-1a), 5.02 (1H, d,
J = 10.8 Hz, CHHPh), 4.91 (1H, d, J = 10.8 Hz, CHHPh), 4.62 (1H, d,
82.0, 64.4, 63.6, 26.2, 24.6; d (a-anomer): 115.3, 102.9, 82.8, 80.9,
80.6, 65.4, 62.3, 26.4, 24.8. IR (film): 3398, 2940, 1644, 1376,
1212, 1161, 1074, 869 cmꢀ1. MS (FAB) m/z: 243 [M+Na]+. HRMS
(FAB) m/z: calcd for C9H16O6Na, 243.0845; found, 243.0848.
J1 ,2 = 3.7 Hz, H-10), 4.59 (1H, d, J1a,1b = 12.1 Hz, H-1b), 4.51–4.17
(11H, m), 3.85 (1H, t, J = 9.2 Hz), 3.69 (1H, dd, J = 11.1, 8.7 Hz),
0
0
3.5. 1,6-Di-O-benzoyl-3,4-O-isopropylidene-
D
-psicofuranose (8)
3.37 (1H, dd, J2 ,3 = 9.7, J1 ,2 = 3.7 Hz, H-20), 3.25 (3H, s), 1.39 (3H,
s), 0.91 (3H, s). 13C NMR (75 MHz, CDCl3) d: 166.1, 165.9, 138.4,
138.3, 138.0, 133.1, 132.9, 130.0, 129.7, 129.6, 129.4, 128.4,
128.3, 128.3, 128.2, 128.2, 128.0, 127.9, 127.9, 127.8, 127.5,
127.0, 126.9, 114.8, 107.9, 97.2, 83.9, 80.6, 80.2, 80.0, 79.3, 75.8,
73.2, 72.8, 71.8, 70.0 (2C), 64.1, 63.9, 54.9, 26.2, 24.6. IR (KBr):
0
0
0
0
To mixture of (42 mg, 0.19 mmol) and 4-(dimethyl-
a
7
amino)pyridine (11.7 mg, 0.096 mmol) in a mixture of pyridine
(0.5 mL) and CH2Cl2 (3 mL) was dropped benzoyl chloride
(0.22 mL, 1.92 mmol) at 0 °C. The mixture was stirred for 30 min

A. Ueda et al. / Carbohydrate Research 345 (2010) 1722–1729
1727
2935, 1721, 1601, 1496, 1452, 1376, 1261, 1094, 863, 803,
711 cmꢀ1. MS (FAB) m/z: 897 [M+Na]+. HRMS (FAB) m/z: calcd
for C51H54O13Na, 897.3462; found, 897.3470.
(2H, m), 7.60 (2H, d, J = 7.3 Hz), 7.45 (2H, d, J = 7.3 Hz), 7.22–6.95
(22H, m), 5.08 (1H, d, J = 12.1 Hz, CHHPh), 5.07 (1H, d, J = 11.5 Hz,
CHHPh), 4.99 (1H, d, J = 12.1 Hz, CHHPh), 4.97 (1H, d, J = 11.5 Hz,
CHHPh), 4.94 (1H, br s, H-10), 4.87 (1H, d, J = 11.2 Hz, CHHPh),
4.86 (1H, d, J3,4 = 5.9 Hz, H-3), 4.73 (1H, d, J = 11.9 Hz, CHHPh),
4.63 (1H, ddd, J5,6a = 7.9, J5,6b = 6.0, J4,5 = 1.3 Hz, H-5), 4.60 (1H, d,
J = 11.9 Hz, CHHPh), 4.52 (1H, d, J = 11.2 Hz, CHHPh), 4.42 (1H,
dd, J3,4 = 5.9, J4,5 = 1.3 Hz, H-4), 4.38 (1H, d, J1a,1b = 11.7 Hz, H-1a),
3.6.3. 2,3,4,6-Tetra-O-benzyl-a-D-galactopyranosyl 1,6-di-O-
benzoyl-3,4-O-isopropylidene-b-
D
-psicofuranoside (17
a
b)
Colorless oil. Rf = 0.59 (30% EtOAc in hexane). ½a D25
ꢃ
+32.1 (c 1.0,
CHCl3). 1H NMR (300 MHz, C6D6) d: 8.35–8.31 (2H, m), 8.14–8.11
(2H, m), 7.48–7.44 (2H, m), 7.38–7.34 (2H, m), 7.22–6.96 (22H, m),
5.44 (1H, br s, H-10), 5.06–5.02 (3H, m), 4.83 (1H, d, J = 11.4 Hz),
4.82 (1H, d, J3,4 = 5.8 Hz, H-3), 4.69–4.55 (7H, m), 4.44–4.40 (1H,
m, H-5), 4.27 (1H, d, J = 11.0 Hz), 4.17–4.13 (3H, m), 4.07 (1H, d,
J = 11.9 Hz), 3.99 (1H, br s), 3.72 (1H, dd, J = 8.5, 8.0 Hz), 3.53 (1H,
dd, J = 8.8, 5.7 Hz), 1.39 (3H, s), 1.11 (3H, s). 13C NMR (75 MHz, CDCl3)
4.25 (1H, dd, J4 ,5 = 9.7, J3 ,4 = 9.4 Hz, H-40), 4.22 (1H, dd,
0
0
0
0
J6a,6b = 11.4, J5,6a = 7.9 Hz, H-6a), 4.13 (1H, d, J1 ,2 = 2.6 Hz, H-20),
4.05 (1H, d, J1a,1b = 11.7 Hz, H-1b), 3.93 (1H, dd, J6a,6b = 11.4,
0
0
0
0
0
0
J5,6h = 6.0 Hz, H-6b), 3.69 (1H, dd, J6 a,6 b = 11.1, J5 ,6 a = 4.1 Hz, H-
60a), 3.55 (1H, dd, J6 a,6 b = 11.1, J5 ,6 b = 1.3 Hz, H-60b), 3.49 (1H,
0
0
0
0
dd, J3 ,4 = 9.4, J2 ,3 = 2.7 Hz, H-30), 3.10 (1H, ddd, J4 ,5 = 9.7,
0
0
0
0
0
0
d: 166.0, 165.9, 138.7, 138.6, 138.3, 137.9, 133.0, 132.7, 130.2, 129.8,
J5 ,6 a = 4.1, J5 ,6 b = 1.3 Hz, H-50), 1.40 (3H, s), 1.13 (3H, s). 13C NMR
(100 MHz, CDCl3) d: 166.1, 165.9, 139.0, 138.4, 138.3, 138.2,
133.5, 132.7, 130.4, 129.8, 129.7, 129.3, 128.6, 128.4, 128.3,
128.2, 128.1, 128.0, 127.9, 127.8, 127.7, 127.6, 127.5, 127.4,
127.3, 127.1, 113.5, 109.9, 93.8, 85.5, 84.9, 83.0, 81.7, 75.8, 75.1
(2C), 74.2, 74.1, 73.2, 71.8, 68.9, 65.0, 62.8, 26.5, 25.8. IR (film):
0
0
0
0
129.7, 128.3, 128.2, 128.1, 128.0, 127.7, 127.6, 127.5, 127.4, 127.3,
113.5, 109.0, 92.5, 84.5, 84.2, 81.9, 79.2, 75.7, 74.9, 74.8, 73.9, 73.2,
72.8, 70.2, 68.3, 64.7, 64.2, 26.5, 24.9. IR (film): 3032, 1723, 1453,
1272, 1099, 711 cmꢀ1. MS (FAB) m/z: 973 [M+Na]+. HRMS (FAB) m/
z: calcd for C57H58O13Na, 973.3775; found, 973.3779.
3031, 2869, 1716, 1602, 1496, 1453, 1374, 1274, 1106, 712 cmꢀ1
.
3.6.4. 2,3,4,6-Tetra-O-benzyl-b-
D-galactopyranosyl 1,6-di-O-
MS (FAB) m/z: 973 [M+Na]+. HRMS (FAB) m/z: calcd for
benzoyl-3,4-O-isopropylidene-b-
D
-psicofuranoside (17bb)
C57H58O13Na, 973.3775; found, 973.3769.
Colorless oil. Rf = 0.59 (30% EtOAc in hexane). ½a D25
ꢀ14.3 (c 0.96,
ꢃ
CHCl3). 1H NMR (300 MHz, C6D6) d: 8.32–8.28 (2H, m), 8.16–8.11
(2H, m), 7.36–7.00 (26H, m), 5.24 (1H, d, J = 11.6 Hz), 5.09 (1H, d,
3.7. Removal of 3,4-O-isopropylidene group of 17
ab and 18ab
J1 ,2 = 7.7 Hz, H-10), 5.00 (1H, d, J = 11.6 Hz), 4.94–4.85 (3H, m),
4.82–4.73 (2H, m), 4.71–4.65 (1H, m), 4.58 (1H, dd, J3,4 = 5.7,
J4,5 = 1.8 Hz, H-4), 4.48–4.37 (2H, m), 4.46 (1H, d, J = 12.3 Hz),
4.36 (1H, d, J = 11.7 Hz), 4.29 (1H, d, J = 11.7 Hz), 4.15 (1H, dd,
J = 9.5, 8.0 Hz), 4.08 (1H, d, J = 11.7 Hz), 3.72 (1H, d, J = 2.4 Hz),
3.59–3.49 (2H, m), 3.37–3.32 (2H, m), 1.36 (3H, s), 1.14 (3H, s).
13C NMR (75 MHz, CDCl3) d: 166.2, 165.7, 138.8, 138.4, 138.3,
137.8, 132.9, 132.5, 130.6, 130.0, 129.8, 129.7, 128.3, 128.1,
128.0, 128.0, 127.9, 127.6, 127.5, 127.5, 127.4, 127.2, 113.4,
109.3, 95.7, 85.8, 85.3, 82.8, 82.1, 79.1, 75.5, 74.4, 73.6, 73.4,
73.2, 72.7, 68.2, 64.7, 63.5, 26.6, 25.3. IR (film): 2870, 1724, 1602,
1453, 1274, 1097, 711 cmꢀ1. MS (FAB) m/z: 973 [M+Na]+. HRMS
(FAB) m/z: calcd for C57H58O13Na, 973.3775; found, 973.3771.
A mixture of 17 b or 18 b (48 mg, 50 mol) and p-toluenesul-
a
a
l
0
0
fonic acid monohydrate (28 mg, 0.15 mmol) was stirred in MeOH
(2.2 mL) at room temperature for 45 h. The reaction was quenched
with satd aq NaHCO3 (5 mL) and extracted with CHCl3 (15 mL ꢂ 3).
Combined organic layers were washed with water and brine
(10 mL each), dried over MgSO4, and evaporated under reduced
pressure. The crude product was purified by flash column chroma-
tography on silica gel eluted with 30% EtOAc in hexane to give diol
20 or 21.
3.7.1. 2,3,4,6-Tetra-O-benzyl-a-D-galactopyranosyl 1,6-di-O-
benzoyl-b-D-psicofuranoside (20)
Colorless oil. 61% yield. Rf = 0.30 (40% EtOAc in hexane). ½a D24
ꢃ
+48.2 (c 0.8, CHCl3). 1H NMR (300 MHz, CDCl3) d: 8.05–8.00 (4H,
3.6.5. 2,3,4,6-Tetra-O-benzyl-
a
-
D
-mannopyranosyl 1,6-di-O-
m), 7.53–7.46 (2H, m), 7.39–7.16 (24H, m), 5.60 (1H, d,
benzoyl-3,4-O-isopropylidene-b-D-psicofuranoside (18a
b)
J1 ,2 = 3.7 Hz, H-10), 4.93 (1H, d, J = 11.4 Hz), 4.85 (1H, d,
J = 11.9 Hz), 4.68 (1H, d, J = 11.7 Hz), 4.63 (1H, d, J = 11.6 Hz),
0
0
Colorless oil. Rf = 0.58 (30% EtOAc in hexane). ½a D20
ꢃ
+6.3 (c 1.0,
CHCl3). 1H NMR (400 MHz, C6D6) d: 8.21–8.18 (2H, m), 8.17–8.15
4.57–4.24 (12H, m), 4.11 (1H, ddd, J5 ,6 a = 8.0, J5 ,6 b = 4.1,
0
0
0
0
J4 ,5 = 1.1 Hz, H-50), 4.00 (1H, dd, J2 ,3 = 9.9, J1 ,2 = 3.7 Hz, H-20),
0
0
0
0
0
0
(2H, m), 7.37–7.33 (2H, m), 7.29–7.20 (6H, m), 7.15–6.93 (18H, m),
5.77 (1H, d, J1 ,2 = 2.0 Hz, H-10), 5.01 (1H, d, J = 11.4 Hz, CHHPh),
4.86 (1H, d, J = 11.9 Hz, CHHPh), 4.73 (1H, d, J3,4 = 5.9 Hz, H-3), 4.68
(1H, dd, J3,4 = 5.9, J4,5 = 2.1 Hz, H-4), 4.68–4.39 (10H, m, 5 ꢂ CHHPh,
3.81 (1H, dd, J2 ,3 = 9.9, J3 ,4 = 2.8 Hz, H-30), 3.78 (1H, dd,
0
0
0
0
0
0
J3 ,4 = 2.8, J4 ,5 = 1.1 Hz, H-40), 3.57 (1H, dd, J6 a,6 b = 9.6,
0
0
0
0
0
0
J5 ,6 a = 8.0 Hz, H-60a), 3.33 (1H, dd, J6 a,6 b = 9.6, J5 ,6 b = 4.1 Hz, H-
60b), 2.55 (1H, d, J = 5.5 Hz, OH). 13C NMR (75 MHz, CDCl3) d:
167.1, 166.3, 138.8, 138.5, 138.3, 137.3, 133.0, 132.9, 130.0,
129.9, 129.7, 129.7, 128.4, 128.3, 128.2, 128.1, 128.1, 128.0,
127.9, 127.6, 127.4, 127.3, 107.2, 90.3, 81.2, 78.9, 75.7, 75.5, 74.4,
73.6, 73.5, 73.4, 72.5, 71.1, 70.4, 70.2, 65.4, 63.8. IR (film): 3453,
2926, 1723, 1602, 1495, 1453, 1374, 1276, 1098, 713 cmꢀ1. MS
(FAB) m/z: 933 [M+Na]+. HRMS (FAB) m/z: calcd for C54H54O13Na,
933.3462; found, 933.3474.
0
0
0
0
0
0
H-1a, 1b, 5, 6a, 6b), 4.41 (1H, dd, J4 ,5 = 9.9, J3 ,4 = 9.3 Hz, H-40), 4.40
0
0
0
0
0
0
0
0
(1H, d, J = 11.9 Hz, CHHPh), 4.26 (1H, ddd, J4 ,5 = 9.9, J5 ,6 b = 4.8,
J5 ,6 a = 1.6 Hz, H-50), 4.22 (1H, dd, J3 ,4 = 9.3, J2 ,3 = 2.9 Hz, H-30),
0
0
0
0
0
0
4.07 (1H, dd, J6 a,6 b = 11.0, J5 ,6 a = 1.6 Hz, H-60a), 4.00 (1H, dd,
0
0
0
0
J6 a,6 b = 11.0, J5 ,6 b = 4.8 Hz, H-60b), 3.98 (1H, dd, J2 ,3 = 2.9,
0
0
0
0
0
0
J1 ,2 = 2.0 Hz, H-20), 1.35 (3H, s), 1.09 (3H, s). 13C NMR (100 MHz,
CDCl3) d: 166.0, 165.4, 138.4, 138.3, 138.2, 138.0, 133.2, 133.1,
129.8, 129.8, 129.7, 128.4, 128.4, 128.3, 128.3, 128.2, 128.2, 127.9,
127.8, 127.7, 127.5, 127.4, 127.4, 127.3, 113.8, 108.7, 91.9, 85.4,
84.7, 81.9, 80.2, 75.1, 74.5, 74.3, 73.4, 73.1, 72.7, 71.8, 69.0, 64.7,
62.8, 26.6, 25.1. IR (film): 3031, 2936, 1729, 1602, 1496, 1453,
1374, 1275, 1112, 870, 699 cmꢀ1. MS (FAB) m/z: 973 [M+Na]+. HRMS
(FAB) m/z: calcd for C57H58O13Na, 973.3775; found, 973.3781.
0
0
3.7.2. 2,3,4,6-Tetra-O-benzyl-a-D-mannopyranosyl 1,6-di-O-
benzoyl- b-D-psicofuranoside (21)
Colorless oil. 63% yield. Rf = 0.37 (40% EtOAc in hexane). ½a D20
ꢃ
+44.6 (c 1.00, CHCl3). 1H NMR (400 MHz, CDCl3) d: 8.10–8.07 (2H,
m), 7.92–7.89 (2H, m), 7.56–7.48 (2H, m), 7.44–7.39 (2H, m), 7.34–
7.21 (18H, m), 7.18–7.12 (4H, m), 5.48 (1H, d, J1 ,2 = 1.3 Hz, H-10),
4.84 (1H, d, J = 10.8 Hz, CHHPh), 4.71 (1H, d, J = 12.5 Hz, CHHPh),
4.67 (1H, d, J = 12.6 Hz, CHHPh), 4.63 (1H, d, J = 12.6 Hz, CHHPh),
4.60 (1H, dd, J6a,6b = 11.9, J5,6a = 6.0 Hz, H-6a), 4.57 (1H, d,
0
0
3.6.6. 2,3,4,6-Tetra-O-benzyl-b-D-mannopyranosyl 1,6-di-O-
benzoyl-3,4-O-isopropylidene-b-D-psicofuranoside (18bb)
Colorless oil. Rf = 0.53 (30% EtOAc in hexane). ½a D20
ꢀ10.1 (c 1.0,
ꢃ
CHCl3). 1H NMR (400 MHz, C6D6) d: 8.33–8.30 (2H, m), 8.14–8.11

1728
A. Ueda et al. / Carbohydrate Research 345 (2010) 1722–1729
J = 11.5 Hz, CHHPh), 4.54 (1H, dd, J6a,6b = 11.9, J5,6b = 3.1 Hz, H-6b),
4.49 (1H, d, J = 11.5 Hz, CHHPh), 4.47 (1H, d, J = 10.8 Hz, CHHPh),
4.33–4.19 (7H, m, CHHPh, H-1a, 1b, 3, 4, 5, OH), 3.96 (1H, ddd,
76.0, 75.7, 75.6, 74.5, 73.4, 72.1, 71.4, 69.9, 64.1, 61.1. IR (KBr):
3397, 2920, 1560, 1455, 1088, 735, 698 cmꢀ1. MS (FAB) m/z: 725
[M+Na]+. HRMS (FAB) m/z: calcd for C40H46O11Na, 725.2938; found,
725.2935.
J4 ,5 = 9.5, J5 ,6 b = 6.8, J5 ,6 a = 1.5 Hz, H-50), 3.83 (1H, dd, J5 ,5 = 9.5,
0
0
0
0
0
0
0
0
J3 ,4 = 8.8 Hz, H-40), 3.79–3.75 (2H, m, H-20, 30), 3.78 (1H, dd,
0
0
J6 a,6 b = 10.1, J5 ,6 a = 1.5 Hz, H-60a), 3.64 (1H, dd, J6 a,6 b = 10.1,
3.8.3. 2,3,4,6-Tetra-O-benzyl-a-D-mannopyranosyl b-D-
psicofuranoside (24)
0
0
0
0
0
0
J5 ,6 b = 6.8 Hz, H-60b), 2.69 (1H, d, J = 5.5 Hz, OH). 13C NMR
(75 MHz, CDCl3) d: 166.6, 166.4, 138.2, 138.1, 138.0, 137.7, 133.4,
133.0, 129.8, 129.7, 129.6, 129.4, 128.4, 128.3, 128.2, 128.1, 128.0,
127.7, 127.6, 127.5, 127.3, 107.0, 90.8, 81.6, 79.9, 75.0, 74.6, 74.0,
73.7, 73.4, 72.4, 72.3, 71.8, 71.6, 69.5, 66.0, 62.8. IR (film): 3444,
0
0
White amorphous solid. Quantitative yield. Rf = 0.55 (EtOAc).
+1.1 (c 0.60, MeOH). 1H NMR (400 MHz, CD3OD) d:
7.42–7.39 (2H, m), 7.36–7.23 (16H, m), 7.19–7.15 (2H, m), 5.56
½ ꢃ
a 2D0
(1H, d, J1 ,2 = 2.0 Hz, H-10), 4.80 (1H, d, J = 11.0 Hz, CHHPh), 4.71
(1H, d, J = 12.5 Hz, CHHPh), 4.68 (1H, d, J = 12.5 Hz, CHHPh), 4.61
(1H, d, J = 12.1 Hz, CHHPh), 4.58 (1H, d, J = 11.7 Hz, CHHPh), 4.54
(1H, d, J = 11.7 Hz, CHHPh), 4.50 (1H, d, J = 11.0 Hz, CHHPh), 4.47
(1H, d, J = 12.1 Hz, CHHPh), 4.17 (1H, dd, J4,5 = 7.7, J3,4 = 4.8 Hz, H-
4), 4.05 (1H, d, J3,4 = 4.8 Hz, H-3), 4.00 (1H, ddd, J4,5 = 7.7,
0
0
3031, 2915, 1714, 1602, 1496, 1454, 1279, 1109, 847, 697 cmꢀ1
.
MS (FAB) m/z: 933 [M+Na]+. HRMS (FAB) m/z: calcd for C54H54O13Na,
933.3462; found, 933.3457.
3.8. Removal of benzoyl protecting groups for 19, 20, and 21
0
0
0
0
J5,6a = 5.9, J5,6b = 3.1 Hz, H-5), 3.95 (1H, dd, J2 ,3 = 2.6, J1 ,2 = 2.0 Hz,
A mixture of 19,9 20, or 21 (16 mg, 50
lmol) and K2CO3 (69 mg,
H-20), 3.93 (1H, dd, J3 ,4 = 8.2, J4 ,5 = 7.9 Hz, H-40), 3.90 (1H, dd,
0
0
0
0
0
0
0
0
0
0
0
0
0.5 mmol) in MeOH (6.6 mL) was stirred for 1 h at room tempera-
ture. The reaction mixture was filtered through a Celite pad (1 cm)
and concentrated under vacuum. The crude material was purified
by flash column chromatography on silica gel eluted with EtOAc
to afford tetraol 22, 23, or 24.
J3 ,4 = 8.2, J2 ,3 = 2.6 Hz, H-30), 3.83 (1H, ddd, J4 ,5 = 7.9, J5 ,6 a = 4.2,
J5 ,6 b = 2.0 Hz, H-50), 3.78 (1H, dd, J6a,6b = 12.1, J5,6a = 5.9 Hz, H-6a),
3.72 (1H, dd, J6a,6b = 12.1, J5,6b = 3.1 Hz, H-6b), 3.70 (1H, d,
0
0
0
0
0
0
J1a,1b = 11.9 Hz, H-1a), 3.70 (1H, dd, J6 a,6 b = 11.0, J5 ,6 a = 4.2 Hz, H-
60a), 3.65 (1H, dd, J6 a,6 b = 11.0, J5 ,6 b = 2.0 Hz, H-60b), 3.59 (1H, d,
J1a,1b = 11.9 Hz, H-1b). 13C NMR (75 MHz, CD3OD) d: 139.8 (2C),
139.8, 139.5, 129.4, 129.3, 129.1, 129.0, 128.7, 128.6, 110.2, 92.5,
85.8, 80.6, 76.6, 76.4, 75.9, 75.8, 74.4, 73.8, 73.4, 72.7, 71.8, 70.1,
63.8, 63.1. IR (KBr): 3448, 2920, 1455, 1091, 737, 698 cmꢀ1. MS
(FAB) m/z: 725 [M+Na]+. HRMS (FAB) m/z: calcd for C40H46O11Na,
725.2938; found, 725.2943.
0
0
0
0
3.8.1. 2,3,4,6-Tetra-O-benzyl-a-D-glucopyranosyl b-D-
psicofuranoside (22)
White amorphous solid. 92% yield. Rf = 0.65 (EtOAc). ½a D20
ꢃ
+32.4
(c 1.0, MeOH). 1H NMR (400 MHz, CD3OD) d: 7.36–7.23 (18H, m),
7.16–7.14 (2H, m), 5.39 (1H, d, J1 ,2 = 3.7 Hz, H-10), 4.88–4.75 (5H,
m, 5 ꢂ CHHPh), 4.56 (1H, d, J = 12.1 Hz, CHHPh), 4.52 (1H, d,
J = 11.4 Hz, CHHPh), 4.46 (1H, d, J = 12.1 Hz, CHHPh), 4.16 (1H,
dd, J4,5 = 8.4, J3,4 = 4.6 Hz, H-4), 4.04 (1H, d, J3,4 = 4.6 Hz, H-3), 4.00
(1H, ddd, J4,5 = 8.4, J5,6a = 6.4, J5,6b = 2.7 Hz, H-5), 3.90 (1H, dd,
0
0
3.9. Removal of benzyl-protecting groups for 22, 23, and 24
To a solution of compound 22, 23, or 24 (17 mg, 24.2 lmol) in
J2 ,3 = 9.9, J3 ,4 = 9.2 Hz, H-30), 3.87 (1H, ddd, J4 ,5 = 10.0, J5 ,6 a = 3.7,
MeOH (2 mL) was added 10% Pd(OH)2 on carbon (4 mg) and stirred
overnight under hydrogen atmosphere (1 atm) at room tempera-
ture. After filtration of the reaction mixture and evaporation of
the filtrate, the crude product was purified by HPLC under the fol-
lowing conditions; column, Chemco pakÒ (Kromasol 5NH2), flow
rate, 5 mL/min, eluent, 25% H2O in MeCN. Retention time,
14.8 min for 1, 15.3 min for 2, and 19.6 min for 3. Evaporation of
the corresponding fractions gave compound 1, 2, or 3.
0
0
0
0
0
0
0
0
J5 ,6 b = 2.2 Hz, H-50), 3.79 (1H, dd, J6a,6b = 12.1, J5,6a = 6.4 Hz, H-6a),
3.76 (1H, d, J1a,1b = 12.5 Hz, H-1a), 3.70 (1H, dd, J6a,6b = 12.1,
0
0
0
0
0
0
J5,6b = 2.7 Hz, H-6b), 3.68 (1H, dd, J6 a,6 b = 11.0, J5 ,6 a = 3.7 Hz, H-
60a), 3.64 (1H, dd, J6 a,6 b = 11.0, J5 ,6 b = 2.2 Hz, H-60b), 3.61 (1H,
0
0
0
0
dd, J2 ,3 = 9.9, J1 ,2 = 3.7 Hz, H-20), 3.58 (1H, dd, J4 ,5 = 10.0,
0
0
0
0
0
0
J3 ,4 = 9.2 Hz, H-40), 3.49 (1H, d, J1a,1b = 12.5 Hz, H-1b). 13C NMR
(75 MHz, CD3OD) d: 140.0, 139.5, 139.3, 138.5, 129.9, 129.6,
129.4, 129.4, 129.3, 129.2, 128.9, 128.8, 128.8, 128.7, 128.6,
110.8, 91.5, 85.8, 83.2, 80.8, 79.2, 76.5, 76.0, 75.7, 75.6, 74.4,
72.7, 71.9, 69.6, 63.9, 61.4. IR (KBr): 3405, 2932, 1454, 1066, 978,
755, 699 cmꢀ1. MS (FAB) m/z: 725 [M+Na]+. HRMS (FAB) m/z: calcd
for C40H46O11Na, 725.2938; found, 725.2944.
0
0
3.9.1. a-D-Glucopyranosyl b-D-psicofuranoside (1)
White solid. Quantitative yield. Rf = 0.55 (25% H2O in MeCN).
Mp 168 °C dec. ½a 2D0
ꢃ
+78.8 (c 0.4, H2O), lit.6
½
a 2D0 +74.36. 1H NMR
ꢃ
(400 MHz, D2O) d: 5.38 (1H, d, J1 ,2 = 3.7 Hz, H-10), 4.26 (1H, dd,
J4,5 = 8.3, J3,4 = 4.8 Hz, H-4), 4.21 (1H, d, J3,4 = 4.8 Hz, H-3), 4.08
(1H, ddd, J4,5 = 8.3, J5,6b = 6.6, J5,6a = 3.5 Hz, H-5), 3.86–3.75 (4H,
m, H-6b, 50, 60a, 60b), 3.84 (1H, dd, J6a,6b = 12.3, J5,6a = 3.5 Hz, H-
0
0
3.8.2. 2,3,4,6-Tetra-O-benzyl-a-D-galactopyranosyl b-D-
psicofuranoside (23)
White amorphous solid. 84% yield. Rf = 0.71 (EtOAc). ½a D20
ꢃ
+27.8
6a), 3.83 (1H, d, J1a,1b = 12.8 Hz, H-1a), 3.71 (1H, dd, J2 ,3 = 9.9,
0
0
(c 1.0, MeOH). 1H NMR (400 MHz, CD3OD) d: 7.41–7.24 (20H, m),
J3 ,4 = 9.2 Hz, H-30), 3.68 (1H, d, J1a,1b = 12.8 Hz, H-1b), 3.58 (1H,
0
0
5.32 (1H, d, J1 ,2 = 3.7 Hz, H-10), 4.82 (1H, d, J = 11.0 Hz, CHHPh),
4.82 (1H, d, J = 10.1 Hz, CHHPh), 4.78 (1H, d, J = 11.5 Hz, CHHPh),
4.75 (1H, d, J = 10.1 Hz, CHHPh), 4.70 (1H, d, J = 11.5 Hz, CHHPh),
4.51 (1H, d, J = 11.0 Hz, CHHPh), 4.51 (1H, d, J = 11.9 Hz, CHHPh),
4.44 (1H, d, J = 11.9 Hz, CHHPh), 4.15 (1H, dd, J4,5 = 8.6,
J3,4 = 4.4 Hz, H-4), 4.08–4.05 (2H, m, H-40, 50), 4.05 (1H, dd,
dd, J2 ,3 = 9.9, J1 ,2 = 3.7 Hz, H-20), 3.46 (1H, dd, J4 ,5 = 9.5,
0
0
0
0
0
0
0
0
J3 ,4 = 9.2 Hz, H-40). 13C NMR (100 MHz, D2O) d: 107.5, 90.4, 81.9,
72.7, 71.2, 71.0, 69.4, 69.1, 67.5, 61.0, 58.6, 58.2. IR (KBr): 3385,
2935, 1654, 1420, 1071, 988 cmꢀ1. MS (FAB) m/z: 365 [M+Na]+.
0
0
HRMS (FAB) m/z: calcd for
365.1055.
C12H22O11Na, 365.1060; found,
J2 ,3 = 10.2, J1 ,2 = 3.7 Hz, H-20), 3.98 (1H, d, J3,4 = 4.4 Hz, H-3), 3.98
(1H, ddd, J4,5 = 8.6, J5,6a = 6.8, J5,6b = 2.6 Hz, H-5), 3.95 (1H, dd,
0
0
0
0
3.9.2. a-D-Galactopyranosyl b-D-psicofuranoside (2)
J2 ,3 = 10.2, J3 ,4 = 2.7 Hz, H-30), 3.77 (1H, dd, J6a,6b = 12.1,
J5,6a = 6.8 Hz, H-6a), 3.74 (1H, d, J1a,1b = 12.3 Hz, H-1a), 3.63 (1H,
White solid. Quantitative yield. Rf = 0.52 (25% H2O in MeCN). Mp
0
0
0
0
170 °C dec. ½a 2D0
ꢃ
+63.7 (c 0.3, H2O). 1H NMR (400 MHz, D2O) d: 5.40
dd, J6a,6b = 12.1, J5,6b = 2.6 Hz, H-6b), 3.54 (1H, dd, J6 a,6 b = 12.0,
(1H, d, J1 ,2 = 3.1 Hz, H-10), 4.27 (1H, dd, J4,5 = 8.2, J3,4 = 4.8 Hz, H-4),
0
0
0
0
J5 ,6 a = 6.8 Hz, H-60a), 3.51 (1H, dd, J6 a,6 b = 12.0, J5 ,6 b = 6.2 Hz, H-
60b), 3.46 (1H, d, J1a,1b = 12.3 Hz, H-1b). 13C NMR (75 MHz, CD3OD)
d: 140.0, 139.9, 139.4, 138.7, 129.9, 129.6, 129.5, 129.3, 129.2,
129.1, 128.8, 128.8, 128.7, 128.7, 110.6, 92.2, 85.7, 80.4, 77.0, 76.1,
4.21 (1H, d, J3,4 = 4.8 Hz, H-3), 4.08 (1H, ddd, J5 ,6 b = 7.0, J5 ,6 a = 5.3,
0
0
0
0
0
0
0
0
0
0
J4 ,5 = 1.3 Hz, H-50), 4.07 (1H, ddd, J4,5 = 8.2, J5,6a = 7.0, J5,6b = 3.5 Hz,
0
0
H-5), 4.01 (1H, dd, J3 ,4 = 2.6, J4 ,5 = 1.3 Hz, H-40), 3.89–3.83 (2H, m,
H-20, 30), 3.86 (1H, dd, J6a,6b = 12.1, J5,6a = 7.0 Hz, H-6a), 3.83 (1H, d,
0
0
0
0

A. Ueda et al. / Carbohydrate Research 345 (2010) 1722–1729
1729
J. Carbohydr. Res. 1967, 5, 106–108; (e) James, K.; Tatchell, A. R.; Ray, P. K. J.
Chem. Soc. C 1967, 2681–2686; (f) D’Antona, N.; El-Idrissi, M.; Ittobane, N.;
Nicolosi, G. Carbohydr. Res. 2005, 340, 319–323; from D-allose (g) Ekeberg, D.;
J1a,1b = 12.6 Hz, H-1a), 3.82 (1H, dd, J6a,6b = 12.1, J5,6b = 3.5 Hz, H-6b),
3.75 (1H, dd, J6 a,6 b = 11.9, J5 ,6 a = 5.3 Hz, H-60a), 3.71 (1H, dd,
0
0
0
0
J6 a,6 b = 11.9, J5 ,6 b = 7.0 Hz, H-60b), 3.68 (1H, d, J1a,1b = 12.6 Hz, H-
1b). 13C NMR (100 MHz, D2O) d: 107.4, 90.5, 81.9, 72.6, 70.0, 69.1,
67.7, 67.5, 66.4, 61.0, 59.4, 58.3. IR (KBr): 3376, 2935, 1637, 1074,
961 cmꢀ1. MS (FAB) m/z: 365 [M+Na]+. HRMS (FAB) m/z: calcd for
0
0
0
0
Morgenlie, S.; Stenstrøn, Y. Carbohydr. Res. 2007, 342, 1992–1997.
4. Chemical synthesis Enders, D.; Grondal, C. Angew. Chem., Int. Ed. 2005, 44,
1210–1212.
5. (a) Hayashi, N.; Iida, T.; Yamada, T.; Okuma, K.; Takehara, I.; Yamamoto, T.;
Yamada, K.; Tokuda, M. Biosci., Biotechnol., Biochem. 2010, 74, 510–519; (b)
Baek, S. H.; Park, S. J.; Lee, H. G. J. Food Sci. 2010, 75, H49–H53; (c) Matsuo, T.;
Izumori, K. Biosci., Biotechnol., Biochem. 2006, 70, 2081–2085; (d) Matsuo, T.;
Izumori, K. J. Clin. Biochem. Nutr. 2009, 45, 202–206; (e) Sun, Y.; Hayakawa, S.;
Ogawa, M.; Izumori, K. Food Control 2007, 18, 220–227; (f) Tanaka, M. K.;
Yamaguchi, F.; Nakanose, K.; Watanabe, Y.; Hatano, N.; Tsukamoto, I.; Nagata,
M.; Izumori, K.; Tokuda, M. J. Biosci. Bioeng. 2005, 100, 511–516; (g) Tokuda, M;
Murao, K.; Ishida, T.; Izumori, K. PCT Int. Appl. WO 2005115409 A1 20051208;
Chem. Abstr. 2005, 144, 617.; (h) Matsuo, T.; Suzuki, H.; Hashiguchi, M.;
Izumori, K. J. Nutr. Sci. Vitaminol. 2002, 48, 77–80.
C12H22O11Na, 365.1060; found, 365.1055.
3.9.3. -Mannopyranosyl b- -psicofuranoside (3)
a-D
D
White solid. Quantitative yield. Rf = 0.50 (25% H2O in MeCN).
Mp 173 °C dec. ½a 2D0
ꢃ
+24.7 (c 0.3, H2O). 1H NMR (400 MHz, D2O)
0
d: 5.31 (1H, d, J1 ,2 = 2.0 Hz, H-10), 4.26 (1H, dd, J4,5 = 8.1,
J3,4 = 4.8 Hz, H-4), 4.19 (1H, d, J3,4 = 4.8 Hz, H-3), 4.06 (1H, ddd,
0
6. 6. Izumori, K.; Morimoto, K. Jpn. Kokai Tokkyo koho JP 2007091667
A
0
0
J4,5 = 8.1, J5,6a = 6.4, J5,6b = 3.7 Hz, H-5), 3.91 (1H, dd, J2 ,3 = 3.3,
20070412, 2007; Chem. Abstr. 2007, 146, 400659.
J1 ,2 = 2.0 Hz, H-20), 3.87 (1H, dd, J3 ,4 = 7.9, J2 ,3 = 3.3 Hz, H-30),
3.86–3.66 (8H, m, H-1a, 1b, 6a, 6b, 40, 50, 60a, 60b). 13C NMR
(100 MHz, D2O) d: 107.4, 91.9, 81.8, 72.8, 71.8, 69.4, 68.9, 68.7,
64.9, 60.9, 59.1, 58.7. IR (KBr): 3388, 2938, 1637, 1419, 1064,
976 cmꢀ1. MS (FAB) m/z: 365 [M+Na]+. HRMS (FAB) m/z: calcd
for C12H22O11Na, 365.1060; found, 365.1064.
0
0
0
0
0
0
7. N-Glycosylation (a) Grouiller, A.; Chattopadhyaya, J. Acta Chem. Scand. B 1984,
38, 367–373; (b) Pradeepkumar, P. I.; Zamaratski, E.; Földesi, A.;
Chattopadhyaya, J. J. Chem. Soc., Perkin Trans. 2 2001, 402–408; (c) Roivainen,
J.; Vepsäläinen, J.; Azhayev, A.; Mikhailopulo, I. A. Tetrahedron Lett. 2002, 43,
6553–6555; (d) Pradeepkumar, P. I.; Cheruku, P.; Plashkevych, O.; Acharya, P.;
Gohil, S.; Chattopadhyaya, J. J. Am. Chem. Soc. 2004, 126, 11484–11499; (e)
Bogucka, M.; Nauš, P.; Pathmasiri, W.; Barman, J.; Chattopadhyaya, J. Org.
Biomol. Chem. 2005, 3, 4362–4372; (f) Honcharenko, D.; Varghese, O. P.;
Plashkevych, O.; Barman, J.; Chattopadhyaya, J. J. Org. Chem. 2006, 71, 299–314.
8. C-Glycosylation (a) Dillon, M. P.; Maag, H.; Muszynski, D. M. Tetrahedron Lett.
1995, 36, 5469–5470; (b) Sano, H.; Mio, S.; Tsukaguchi, N. Sugai, S. 1995, 51,
1387–1394.
9. Uenishi, J.; Ueda, A. Tetrahedron: Asymmetry 2008, 19, 2210–2217.
10. Uenishi, J.; Ueda, A. Heterocycles 2009, 77, 1297–1305.
11. Hirano, S.; Ichikawa, S.; Matsuda, A. J. Org. Chem. 2007, 72, 9936–9946.
12. Yamanoi, T.; Ishiyama, T.; Oda, Y.; Matsuda, S.; Watanabe, M. Heterocycles
2010, 81, 1141–1147.
Acknowledgments
This work was supported by the 21st COE Program from the
Ministry of Education, Culture, Sports, Science, and Technology,
Japan.
Supplementary data
13. Kim, K. S.; Lee, Y. J.; Kim, H. Y.; Kang, S. S.; Kwon, S. Y. Org. Biomol. Chem. 2004,
2, 2408–2410.
14. Elhalabi, J.; Rice, K. G. Carbohydr. Res. 2001, 335, 159–165.
15. Nicolaou, K. C.; van Delft, F. L.; Conley, S. R.; Mitchell, H. J.; Zin, Z.; Rodríguez, R.
M. J. Am. Chem. Soc. 1997, 119, 9057–9058. and references cited therein.
16. (a) Lemieux, R. U.; Huber, G. J. Am. Chem. Soc. 1953, 75, 4118; (b) Lemieux, R. U.;
Huber, G. J. Am. Chem. Soc. 1956, 78, 4117–4119; (c) Tsuchida, H.; Komoto, M.
Agric. Biol. Chem. 1965, 29, 239–242; (d) Ness, R. K.; Fletcher, H. G., Jr.
Carbohydr. Res. 1971, 17, 465–470; (e) Iley, D. E.; Fraser-Reid, B. J. Am. Chem.
Soc. 1975, 97, 2563–2565; (f) Fraser-Reid, B.; Iley, D. E. Can. J. Chem. 1979, 57,
645–652.
17. (a) Nicolaou, K. C.; Mitchell, H. J.; Fylaktakidou, K. C.; Rodríguez, R. M.; Suzuki,
H. Chem. Eur. J. 2000, 6, 3116–3148; (b) Nicolaou, K. C.; Fylaktakidou, K. C.;
Mitchell, H. J.; van Delft, F. L.; Rodríguez, R. M.; Conley, S. R.; Jin, Z. Chem. Eur. J.
2000, 6, 3166–3185.
Supplementary data associated with this article can be found, in
the online version, at doi:10.1016/j.carres.2010.05.030.
References
1. (a) Garrett, E. R. J. Am. Chem. Soc. 1960, 82, 827–832; (b) Hough, L.; Stacey, B. E.
Phytochemistry 1963, 2, 315–320; (c) Hough, L.; Stacey, B. E. Phytochemistry
1966, 5, 215–222.
2. (a) Itoh, H.; Sato, T.; Izumori, K. J. Ferment. Bioeng. 1995, 80, 101–103; (b)
Takeshita, K.; Suga, A.; Takada, G.; Izumori, K. J. Biosci. Bioeng. 2000, 90, 453–
455.
3. Chemical transformations from other sugars; from
D-ribose, (a) Wolfrom, M. L.;
18. Oscarson, S.; Sehgelmeble, F. W. J. Am. Chem. Soc. 2000, 122, 8869–8872.
19. Namme, R.; Mitsugi, T.; Takahashi, H.; Ikegami, S. Eur. J. Org. Chem. 2007, 3758–
3764.
Thompson, A.; Evans, E. F. J. Am. Chem. Soc. 1945, 67, 1793–1797; from
D-
fructose (b) Heyns, K.; Paulsen, H.; Schroeder, H. Tetrahedron 1961, 13, 247–
257; (c) Passeron, S.; Recondo, E. J. Chem. Soc. 1965, 813–815; (d) McDonald, E.