Formation of O-glycosidic linkages from 1-hydroxy sugars by bismuth(III) triflate-catalyzed dehydrative glycosidation

Article abstract of DOI:10.3987/COM-08-S(F)41

This paper describes the direct formation of various O-glycosidic linkages from 1-hydroxy sugars by bismuth(III) triflate-catalyzed dehydrative glycosidation. The condensation reactions of 1 -hydroxy sugars with some primary alcohols in the presence of on

Full text of DOI:10.3987/COM-08-S(F)41

HETEROCYCLES, Vol. 77, No. 1, 2009
445
HETEROCYCLES, Vol. 77, No. 1, 2009, pp. 445 - 460. © The Japan Institute of Heterocyclic Chemistry
Received, 7th July, 2008, Accepted, 22nd August, 2008, Published online, 25th August, 2008.
DOI: 10.3987/COM-08-S(F)41
FORMATION OF O-GLYCOSIDIC LINKAGES FROM 1-HYDROXY
SUGARS BY BISMUTH(III) TRIFLATE-CATALYZED DEHYDRATIVE
GLYCOSIDATION
Takashi Yamanoi,a,* Ryo Inoue,a,b Sho Matsuda,a Kazuya Iwao,a Yoshiki
Oda,a Akihiro Yoshida,a and Keita Hamasakib
aThe Noguchi Institute, 1-8-1 Kaga, Itabashi-ku, Tokyo 173-0003, Japan, E-mail:
b
tyama@noguchi.or.jp Department of Applied Chemistry, Shibaura Institute of
Technology, 3-7-5 Toyosu, Koto-ku, Tokyo 135-8548, Japan
Abstract – This paper describes the direct formation of various O-glycosidic
linkages from 1-hydroxy sugars by bismuth(III) triflate-catalyzed dehydrative
glycosidation. The condensation reactions of 1-hydroxy sugars with some primary
alcohols in the presence of only 5 mol% bismuth(III) triflate at reflux temperature
for 15 min in dichloromethane afforded O-glycosides in good yields. An
1,6-anhydro-β-D-glucopyranosidic linkage was formed by the intramolecular
condensation of the corresponding 1-hydroxy sugar performed with similar
reaction conditions using 5 mol% bismuth(III) triflate. A reaction using 10 mol%
bismuth(III) triflate at room temperature in dichloromethane promoted the self- or
cross-condensations of 1-hydroxy sugars to produce several kinds of
1,1’-disaccharides. This paper reports some important properties of bismuth(III)
triflate catalyzed dehydrative glycosidation using 1-hydroxy sugars to form
various O-glycosidic linkages.
INTRODUCTION
The development of an efficient preparation of complex glycosides is a major focus in synthetic
carbohydrate chemistry.1 Dehydrative glycosidation of 1-hydroxy sugars, which are easy to prepare and
handle, can be a simple and versatile method for glycosidic bond formations.2 Due to the generally poor
leaving ability of the anomeric hydroxyl group of 1-hydroxy sugars, most of the conventional dehydrative
O-glycosidation methods using 1-hydroxy sugars require the formation of a highly reactive glycosyl
This paper is dedicated to Professor Emeritus Keiichiro Fukumoto on the occasion of his 75th birthday.

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HETEROCYCLES, Vol. 77, No. 1, 2009
donor in the reaction system by in situ introduction of a transient leaving group at its anomeric hydroxyl
group.3
Dehydrative glycosidation by an acid catalyst, which can directly activate the hemiacetal hydroxyl group
of 1-hydroxy sugars, is considered to be a more practical approach because it does not require a transient
leaving group. However, there have been only a few reports on such dehydrative glycosidation
approaches using an acid catalyst.4 This type of dehydrative glycosidation, called “Fischer glycosidation”,
requires the use of large excesses of acid (activator) and alcohol (acceptor) in order to increase the
reactivity.5 It is problematic that the reaction system using the stoichiometric amounts of an alcohol
produces 1,1’-disaccharide (a non-reducing disaccharide) as a byproduct through self-condensation of
1-hydroxy sugars.6 Therefore, it is important to develop an efficient dehydrative O-glycosidation method
that does not require excess amounts of acid and alcohol in order to prevent the formation of the
1,1′-disaccharides. On the other hand, there is currently a significant emphasis on the study of the
biologically novel functions of 1,1’-disaccharide derivatives, which are structurally-classified as trehalose
analogs.7 Therefore, the establishment of an efficient method for preparing 1,1’-disaccharides directly
from 1-hydroxy sugars also becomes one of the most noteworthy subjects in dehydrative glycosidation
studies.8
Our previous work showed that the O-ketopyranosidation9 via the dehydrative condensation of artificial
ketopyranoses, i.e., 1-C-alkylated sugar derivatives, proceeded easily when using catalytic bismuth(III)
triflate (Bi(OTf)3) as the activator.10 This finding prompted us to test the applicability of Bi(OTf)3 in
dehydrative O-aldosylation using 1-hydroxy sugars.11 We then investigated the direct formation of
various O-glycosidic linkages from 1-hydroxy sugars by dehydrative glycosidation using Bi(OTf)3. Part
of the study, as reported in our preliminary letter, showed that the condensation of 1-hydroxy sugars with
several primary alcohols in the presence of only 5 mol% Bi(OTf)3 at reflux temperature for 15 min
produced O-aldopyranosides and also controlled the production of undesirable 1,1’-disaccharides.12 Our
other studies of glycosidation using Bi(OTf)3 revealed the following significant findings. The
O-D-arabinofuranosidic and 1,6-anhydro-β-D-glucopyranosidic linkages were formed from the
corresponding 1-hydroxy sugars under the similar glycosidation systems using 5 mol% Bi(OTf)3. In
addition, various 1,1’-disaccharides were produced in good yields by self- or cross-condensation with
1-hydroxy sugars in the presence of 10 mol% Bi(OTf)3 at room temperature.
This paper describes the direct formation of various O-glycosidic linkages from 1-hydroxy sugars by
Bi(OTf)3-catalyzed dehydrative glycosidation.
RESULTS AND DISCUSSION
The 1-hydroxy sugars and alcohols used in this study are shown in Figures 1 and 2. The typical

HETEROCYCLES, Vol. 77, No. 1, 2009
447
O-glycosides and 1,1’-disaccharides produced are shown in Figures 3 and 4.
1: R1= OBn, R2= H, R3= OBn, R4= H, R5= OBn
2: R1= H, R2= OBn, R3= OBn, R4= H, R5= OBn
3: R1= OBn, R2= H, R3= H, R4= OBn, R5= OBn
4: R1= N3, R2= H, R3= OBn, R4= H, R5= OBn
5: R1= OBn, R2= H, R3= OBn, R4= H, R5= OH
BnO
R5
R2
O
O
R4
BnO OH
R3
BnO
BnO
OH
R1
6
Figure 1. 1-Hydroxy sugars used
HO
BnO
BnO
O
HO
HO
BnO
OMe
8
9
7
HO
HO
HO
12
10
11
Figure 2. Alcohols used
OBn
R2
O
BnO
R4
13: R1= OBn, R2= H, R3= OBn, R4= H
14: R1= H, R2= OBn, R3= OBn, R4= H
15: R1= OBn, R2= H, R3= H, R4= OBn
16: R1= N3, R2= H, R3= OBn, R4= H
O
BnO
O
R3
BnO
O
R1
BnO
17
OBn
R2
O
BnO
BnO
OBn
O
O
20: R5=
21: R5=
22: R5=
23: R5=
R1
BnO
BnO
O
BnO
BnO
18: R1= OBn, R2= H
19: R1= H, R2= OBn
BnO
OMe
BnO OR5
OH
O
O
OBn
BnO
BnO
O
O
BnO
Bn
OBn OBn
24
25
Figure 3. Typical O-glycosides produced

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HETEROCYCLES, Vol. 77, No. 1, 2009
BnO
OBn
R2
O
26: R1= OBn, R2= H, R3= OBn, R4= H
27: R1= H, R2= OBn, R3= OBn, R4= H
28: R1= OBn, R2= H, R3= H, R4= OBn
29: R1= N3, R2= H, R3= OBn, R4= H
R4
BnO
O
BnO
R3
OBn
O
O
R1
O
R2
BnO
BnO
O
OBn
OBn
R3
R1
BnO
30
R4
BnO
O
OBn
O
BnO
O
OBn
OBn
BnO
BnO
31
Figure 4. 1,1'-Disaccharides produced
1. Dehydrative glycosidation for producing typical O-glycosides (Scheme 1, Table 1)
We first investigated the glycosidation of 2,3,4,6-tetra-O-benzyl-D-glucopyranose (1) with an equimolar
amount of 2-phenylethyl alcohol (7). The amount of Bi(OTf)3 was varied in CH2Cl2 for 2 h at room
temperature in the presence of a drying agent, anhydrous calcium sulfate (CaSO4). These reaction
conditions were similar to those previously reported.13 The reaction using 5 mol% Bi(OTf)3 afforded the
corresponding glycoside 13 in only 35% yield. The use of 10 mol% Bi(OTf)3 effectively promoted the
glycosidation to produce 13 in a respectable yield of 85% with an α/β ratio of 71/29. It is noteworthy that
under these reaction conditions the production of 1,1’-disaccharide 26 decreased only to a 7% yield. The
use of 20 mol% Bi(OTf)3 slightly reduced the yield of 13 to 68% with an increase in the yield of 26 to
13%. When the reaction temperature was raised to reflux temperature, the glycosidation using only 5
mol% Bi(OTf)3 in CH2Cl2 for 15 min easily proceeded to produce 13 in a good yield of 87% (α/β =
69/31) with the formation of 26 in only 9% yield. A similar reaction using a mixed CH2Cl2/MeCN (v/v =
1/2) solvent at reflux temperature gave 13 in 72% yield (α/β = 34/66). The effect of other metal triflates
was examined. Similar reaction conditions employing 5 mol% scandium(III) triflate (Sc(OTf)3) and
ytterbium(III) triflate (Yb(OTf)3) afforded 13 in 82% yield (α/β = 65/35) and 14% yield (α/β = 44/56),
respectively. Sc(OTf)3 was fairly effective in dehydrative glycosidation. Thus, a reaction using only 5
mol% Bi(OTf)3 at reflux temperature in CH2Cl2 for 15 min effectively promoted the glycosidation
between 1 and 7 (1 equivalent) to produce the desired glycoside 13 with only a slight production of 26.
activator
O
O
O
+
+
ROH
O
OR
OH
O
CH2Cl2, anhydrous CaSO4
1-6
7-12
13-25
26-30
Scheme 1

HETEROCYCLES, Vol. 77, No. 1, 2009
449
Table 1. The Formation of O-glycosides by the reactions of 1-6 with 7-12.
Glycoside
1,1'-Disaccharide
Product Yield/ %
1-Hydroxy
Entrya
Alcohol Activator (mol%)
Yield/ %
(α/β)b
sugar
Product
1c
2c
3d
4
1
1
1
1
1
1
1
1
1
1
1
1
2
2
3
4
6
5
5
7
Bi(OTf)3 (5)
Bi(OTf)3 (10)
Bi(OTf)3 (20)
Bi(OTf)3 (5)
Bi(OTf)3 (5)
Sc(OTf)3 (5)
Yb(OTf)3 (5)
Bi(OTf)3 (5)
13
13
13
13
13
13
13
18
35 (57/43)
85 (71/29)
68 (57/43)
87 (69/31)
72 (34/66)
82 (65/35)
14 (44/56)
85 (62/38)
71 (60/40)
52 (75/25)
40 (80/20)
58 (65/35)
73 (α only)
81 (91/9)
70 (77/23)
51 (52/48)
81 (85/15)
73
26
26
26
26
26
26
26
26
26
26
26
26
27
27
28
29
30
−
4
7
7
7
13
9
7
5e
7
17
11
4
6
7f
7
7
8
8
9
9
8
Bi(N(SO2-n-C8F17)2)3 (5) 18
10
11
21
17
16
16
10
33
5
10
11g
12
13
14
15
16
17
18
19h
9
Bi(OTf)3 (5)
Bi(OTf)3 (5)
Bi(OTf)3 (5)
Bi(OTf)3 (5)
Bi(OTf)3 (5)
Bi(OTf)3 (5)
Bi(OTf)3 (5)
Bi(OTf)3 (5)
Bi(OTf)3 (5)
Bi(OTf)3 (20)
20
21
22
14
19
15
16
17
24
25
10
11
7
8
7
7
7
−
12
−
78 (65/35)
−
−
aReaction conditions: molar ratio of donor : acceptor = 1 : 1; solvent = CH2Cl2; reflux temperature; reaction time =
15 min. bAll the α/β ratios were determined by NMR. cReaction conditions: room temperature; reaction time = 12 h.
dReaction conditions: room temperature; reaction time = 2 h. eThe mixed solvent (CH2hCl2/MeCN = 1/2) was used.
g
fReaction time = 40 min. Compound 23 was obtained in 31% yield as a byproduct. Reaction conditions: molar
ratio of donor : acceptor = 1 : 10; compound 24 was obtained in 16% yield.
Next, we examined the glycosidation of 1 with various alcohols (1 equivalent) using 5 mol% Bi(OTf)3 at
reflux temperature in CH2Cl2 for 15 min. A reaction using n-octanol (8) produced the glycoside 18 in a
good yield of 85% (α/β = 62/38) with the formation of 26 in only 9% yield. The glycosylation of 1 to
methyl 2,3,4-tri-O-benzyl-α-D-glucopyranoside (9) afforded 20 in a moderate yield of 52% (α/β = 75/25)
with the production of 26 in 11% yield. Even reactions using less reactive acceptors such as phenol (10)
and 1-adamantanol (11) produced the corresponding glycosides 21 and 22 in 40% (α/β = 80/20) and 58%

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(α/β = 65/35) yields with the formation of 26 in 21% and 17% yields, respectively. In addition, during the
reaction using 10, the benzyl glucoside 23 was obtained as a new byproduct in 31% yield. It seemed that
the benzyl alcohol was formed along with the degradation of 1 under the given reaction conditions using
10. The glycosidation of 1 with some primary alcohols afforded the desired glycosides in good yields. In
contrast, for the reactions using less reactive alcohols, the yields of the desired glycosides decreased due
to increase in the yield of 26 and the appearance of a new byproduct 23.
Similarly, 2,3,4,6-tetra-O-benzyl-D-mannopyranose (2), 2,3,4,6-tetra-O-benzyl-D-galactopyranose (3),
2-azido-3,4,6-tri-O-benzyl-2-deoxy-D-glucopyranose (4) and 2,3,5-tri-O-benzyl-D-arabinofuranose (6)
were used as 1-hydroxy sugars. The reaction of 2 with 7 or 8 under the reaction conditions using 5 mol%
Bi(OTf)3 at reflux temperature for 15 min stereoselectively afforded the corresponding glycosides 14 or
19 in 73% yield (α only) or 81% yield (α/β = 91/9) and the production of the 1,1’-disaccharide 27 in 16%
yield in both cases. Similar reaction conditions using 3, 4, or 6 with 7 gave the glycosides 15, 16 or 17 in
70% yield (α/β = 77/23), 51% yield (α/β = 52/48) or 81% yield (α/β = 85/15) with the production of the
1,1’-disaccharide 28, 29 or 30 in 10%, 15% or 5% yield, respectively. The reaction of 1 with 8 using 5
14
mol% Bi(N(SO2-n-C8F17)2)3 instead of Bi(OTf)3 afforded 18 in 71% yield (α/β = 60/40) with the
production of 26 in 16% yield.
The formation of an 1,6-anhydro-β-glucopyranosidic linkage from 2,3,4-tri-O-benzyl-D-glucopyranose
(5) was examined. The reaction conditions using 5 mol% Bi(OTf)3 at reflux temperature for 15 min in
CH2Cl2
easily
promoted
intramolecular
condensation
of
5
to
give
1,6-anhydro-2,3,4-tri-O-benzyl-β-D-glucopyranose (24) in 73% yield. A reaction using 5 and allyl
alcohol (10 equivalent) in the presence of 20 mol% Bi(OTf)3 produced the allyl O-glycoside 25 in 78%
yield (α/β = 65/35) as a main product and 24 was given in only 16% yield. This result indicated that
under theses reaction conditions the intermolecular condensation of 5 with allyl alcohol preceded the
intramolecular condensation of 5.
2. Dehydrative glycosidation for producing 1,1’-disaccharides (Scheme 2, Table 2)
activator
O
O
O
OH
O
CH2Cl2, anhydrous CaSO4
1-4, 6
26-31
Scheme 2
We next, investigated the formation of the symmetrical 1,1’-disaccharide 26 by the self-condensation of 1
in detail. The reactions using 5 mol% and 10 mol% Bi(OTf)3 at reflux temperature for 15 min promoted

HETEROCYCLES, Vol. 77, No. 1, 2009
451
the self-condensation of 1 to produce 26 in 77% and 71% yields. At the same time, however, the benzyl
glucoside 23 was obtained as a byproduct in 19% and 14% yields, respectively. The reaction using 5
mol% Bi(OTf)3 at room temperature for 15 h afforded 26 in only 12% yield with no production of 23. The
use of 10 mol% Bi(OTf)3 at room temperature increased the yield of 26 to 85% with an αα/αβ/ββ isomer
ratio of 53/33/14. The use of 50 mol% Bi(OTf)3 decreased the yield of 26 to 59% and increased the yield
of 23 to 35%. The increase of Bi(OTf)3 seemed to promote the degradation of 1.
The effect of other metal triflates was also examined using Sc(OTf)3 and Yb(OTf)3. Sc(OTf)3 was a fairly
effective activator for the production of 26 in 67% yield, while Yb(OTf)3 was completely ineffective.
This result roughly corresponded to that of entries 6 and 7 in Table 1.
Table 2. The formation of 1,1’-disaccharides by the self- or cross-condensations of 1-6.
1,1'-Disaccharide
Entrya
1-Hydroxy sugar
Activator (mol%)
Yield/ % (αα/αβ/ββ)b
Product
26
1c
2d
3
1
Bi(OTf)3 (5)
Bi(OTf)3 (10)
Bi(OTf)3 (5)
Bi(OTf)3 (10)
Bi(OTf)3 (20)
Bi(OTf)3 (50)
Sc(OTf)3 (20)
Yb(OTf)3 (20)
Bi(OTf)3 (10)
Bi(OTf)3 (10)
Bi(OTf)3 (20)
Bi(OTf)3 (50)
Bi(OTf)3 (100)
Bi(OTf)3 (10)
Bi(OTf)3 (10)
77
1
26
71
1
26
12
4
1
26
85 (53/33/14)
84 (65/29/6)
59
5
6e
1
26
1
26
7
1
26
67 (55/32/13)
−
8
1
26
9f
2
27
85 (ααonly)
70 (71/29/0)
−
10g
11
12
13
14h
15h,i
3
28
4
29
4
29
23
4
29
53 (35/32/33)
93 (85/15/0)
74 (31/31/31/7)k
6
30
31j
6, 1
aReaction conditions: solvent = CH2Cl2; room temperature; reaction time = 1 d. bAll the isomer ratios were
determined by NMR. cReaction conditions: reflux temperature; reaction time = 10 min; compound 23 was obtained
in 19% yield as a byproduct. dReaction conditions: reflux temperature; reaction time = 10 min; compound 23 was
obtained in 14% yield as a byproduct. eCompound 23 was obtained in 35% yield. fReaction conditions: room
temperature; reaction time = 1 h. gReaction conditions: 0 oC; reaction time = 1 d. hReaction conditions: 0 oC;
reaction time = 3.5 h. iReaction conditions: molar ratio of 6 : 1 = 1 : 1.5. jCompound 30 was obtained in 11% yield.
kIsomer ratios of Glcα-αAra/Glcα-βAra/Glcβ-αAra/Glcβ-βAra.

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Subsequently, the synthesis of various symmetrical 1,1’-disaccharides 27, 28, 29 and 30 by the
self-condensation of the 1-hydroxy sugars 2-4 and 6 was examined. Similar reaction conditions using 10
mol% Bi(OTf)3 in CH2Cl2 at room temperature for 3 to 15 h successfully gave 27, 28 and 30 in good
yields of 85% (αα only), 70% (αα/αβ/ββ= 71/29/0) and 93% (αα/αβ/ββ= 85/15/0) from 2, 3 and 6.
However, the same reaction conditions were not applicable to self-condensation using 4 at all. The
reaction conditions using 100 mol% Bi(OTf)3 increased the yield of 29 up to 53% (αα/αβ/ββ= 35/32/33).
We observed that the reactivity of 6 was higher than that of 1. Next, the synthesis of the unsymmetrical
structural 1,1’-disaccharide 31 by the cross-condensation using 6 and 1 was examined. The reaction of 6
with 1 (1.5 equivalent) using 10 mol% Bi(OTf)3 for 3.5 h afforded the desired 31 in a good yield of 74%
with a mixture of αα/αβ/βα/ββ isomers = 31/31/31/7. Under these reaction conditions 30 was obtained in
11% yield and 26 was scarcely produced.
CONCLUSIONS
The direct formation of various O-glycosidic linkages from 1-hydroxy sugars by Bi(OTf)3-catalyzed
dehydrative glycosidation was demonstrated. The reactions of several benzylated 1-hydroxy sugars with
certain primary alcohols using only 5 mol% Bi(OTf)3 at reflux temperature in dichloromethane for 15 min
successfully afforded the desired O-glycosides in good yields. These reaction conditions controlled the
formation of unwanted 1,1’-disaccharides. The application of a similar reaction system effectively led to
the formation of an 1,6-anhydro-β-D-glucopyranosidic linkage from the corresponding 1-hydroxy sugar.
Self- or cross-condensation with 1-hydroxy sugars was promoted by 10 mol% Bi(OTf)3 in CH2Cl2 at
room temperature and produced various symmetrical or unsymmetrical 1,1’-disaccharides. Therefore, we
believe that our dehydrative glycosidation procedure can contribute to the convenient production of
certain chemically or biologically useful glycosides.
EXPERIMENTAL
1H NMR (600 MHz) and 13C NMR (150 MHz) spectra were recorded on a JEOL ECA-600 spectrometer
in CDCl3 using TMS as an internal standard. Optical rotations were recorded on a JASCO DIP-360
digital polarimeter. HRMS were obtained on a Mariner spectrometer (PerSeptive Biosystems Inc.).
Preparative TLC was performed using Merck silica gel 60GF254. Column chromatography was
conducted using silica gel 60 N (40~50 μm, Kanto Chemical Co., INC.). Bi(OTf)3 was purchased from
Sigma-Aldrich. All anhydrous solvents were purified according to standard methods.
2-Phenylethyl 2,3,4,6-Tetra-O-benzyl-D-glucopyranoside (13) (Table 1, Entry 4): To a stirred
suspension of Bi(OTf)3 (5.4 mg, 0.0082 mmol) and 7 (20.3 mg, 0.17 mmol) in CH2Cl2 (3 mL) was added

HETEROCYCLES, Vol. 77, No. 1, 2009
453
1 (89.2 mg, 0.17 mmol) in the presence of anhydrous CaSO4 (ca. 100 mg) under an Ar atmosphere. The
resulting mixture was stirred at reflux temperature for 15 min. The reaction was then quenched by the
addition of a saturated aqueous NaHCO3 solution (5 mL). The reaction mixture was extracted with EtOAc,
and the organic layer was washed with water and a saturated aqueous NaCl solution. After the organic
layer was dried over Na2SO4, the solvent was evaporated under reduced pressure. The crude product was
purified using a preparative silica gel TLC (PTLC; EtOAc/hexane = 1/3) to give the desired glycoside 13
(92.4 mg, 87%, a mixture of α and β anomers) as a colorless oil and 1,1’-disaccharide 26 (8.3 mg, 9%) as
1
a colorless oil. H NMR δ 2.92-2.99 (m, CH2CH2Phαβ), 3.99 (dd, J = 8.2 Hz, J = 8.9 Hz, H-3α),
13
4.19-4.23 (m, CHaHbCH2Phβ), 4.41 (d, J = 7.6 Hz, H-1β), 4.77 (d, J = 3.4 Hz, H-1α); C NMR δ 35.9,
36.2, 68.4, 68.7, 68.9, 70.1, 70.6, 73.1, 73.36, 73.41,74.6, 74.80, 74.82, 74.9, 75.59, 75.60, 77.6, 77.8,
80.0, 81.9, 82.2, 84.6, 96.8 (C-1α), 103.6 (C-1β); HRMS (ESI, α/β mixture) m/z calcd for 667.3030
(C42H44O6+Na+), found 667.2993.
Octyl 2,3,4,6-Tetra-O-benzyl-D-glucopyranoside (18) (Table 1, Entry 8): The same procedure used for
the preparation of 13 using Bi(OTf)3 (5.1 mg, 0.0078 mmol), 8 (20.2 mg, 0.16 mmol), and 1 (84.1 mg,
0.16 mmol) in CH2Cl2 (3 mL) gave the desired glycoside 18 (PTLC; EtOAc/hexane = 1/3, 85.6 mg, 85%,
a mixture of α and β anomers) as a colorless oil and 26 (7.1 mg, 9%). (Table 1, Entry 9): The same
procedure using Bi(N(SO2-n-C8F17)2)3 (32.2 mg, 0.01 mmol), 8 (27.0 mg, 0.2 mmol), and 1 (111.9 mg,
0.21 mmol) in CH2Cl2 (3 mL) gave the desired glycoside 18 (92.1 mg, 71%, a mixture of α and β
1
anomers) and 26 (11.5 mg, 10%). H NMR δ 0.86-0.89 (m, CH3), 1.27-1.70 (m, (CH2)6), 3.40-3.47 (m,
H-2β, H-5β, CHaHb(CH2)6CH3α), 3.51-3.69 (m, H-2α, H-4α, Ha-6α, CHaHb(CH2)6CH3α, H-3β, H-4β,
Ha-6β, CHaHb(CH2)6CH3β), 3.72 (dd, J = 3.4 Hz, J = 10.3 Hz, Hb-6α), 3.73-3.75 (m, Hb-6β), 3.77-3.80
(m, H-5α), 3.95-3.99 (m, CHaHb(CH2)6CH3β), 3.99 (dd, J = 8.9 Hz, J = 9.6 Hz, H-3α), 4.39 (d, J = 7.6
Hz, H-1β), 4.76 (d, J = 4.1 Hz, H-1α); 13C NMR δ 14.1, 22.6, 26.11, 26.14, 29.18, 29.21, 29.3, 29.3, 29.4,
29.7, 31.8, 31.8, 68.2, 68.5, 69.0, 70.0, 70.1, 73.1, 73.4, 73.4, 74.7, 74.8, 74.9, 75.0, 75.6, 75.6, 77.7, 77.9,
80.1, 82.1, 82.2, 84.7, 96.8 (C-1α), 103.6 (C-1β); HRMS (ESI, α/β mixture) m/z calcd for 675.3656
(C42H52O6+Na+), found 675.3680. (Lit.,15 α anomer: 1H NMR δ 4.76 (J = 2.1 Hz, H-1); 13C NMR δ 96.8
(C-1); β anomer: 1H NMR δ 4.39 (J = 7.6 Hz, H-1); 13C NMR δ 103.6 (C-1)).
Methyl 6-O-(2,3,4,6-Tetra-O-benzyl-D-glucopyranosyl)-2,3,4-tri-O-benzyl-α-D-glucopyranoside (20)
(Table 1, Entry 10): The same procedure used for the preparation of 13 using Bi(OTf)3 (5.0 mg, 0.0076
mmol), 9 (70.8 mg, 0.15 mmol), and 1 (82.4 mg, 0.15 mmol) in CH2Cl2 (3 mL) gave the desired
glycoside 20 (PTLC; EtOAc/hexane = 1/3, 77.7 mg, 52%, a mixture of α and β anomers) as a colorless
1
oil and 26 (9.2 mg, 11%). H NMR δ 3.25 (s, CH3β), 3.35 (s, CH3 α), 3.43 (dd, J = 3.4 Hz, J = 8.9 Hz,

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H-2’α), 3.48-3.57 (m, H-2α, H-2’β), 3.94-4.01 (m, H-3’α, H-3α), 4.35 (d, J = 8.2 Hz, H-1’β), 4.50-4.62
13
(m, H-1α, H-1β), 4.98 (d, J = 4.1 Hz, H-1’α); C NMR δ 97.2 (C-1’αα), 97.9 (C-1αα), 98.0 (C-1βα),
103.7 (C-1’βα); HRMS (ESI, α/β mixture) m/z calcd for 1009.4497 (C62H66O11+Na+), found 1009.4479.
(Lit.,16 α anomer: 1H NMR δ 4.98 (J = 3.7 Hz, H-1’); 13C NMR δ 97.9 (C-1’); β anomer: 1H NMR δ 4.34
(J = 7.8 Hz, H-1’); 13C NMR δ 103.7 (C-1’)).
Phenyl 2,3,4,6-Tetra-O-benzyl-D-glucopyranoside (21) (Table 1, Entry 11): The same procedure used
for the preparation of 13 using Bi(OTf)3 (5.4 mg, 0.0082 mmol), 10 (15.6 mg, 0.16 mmol), and 1 (89.0
mg, 0.16 mmol) in CH2Cl2 (3 mL) gave 21 (PTLC; toluene/EtOAc = 10/1, 40.3 mg, 40%, a mixture of α
and β anomers) as a colorless oil, 26 (18.5 mg, 21%) as a colorless oil and 2317 (32.2 mg, 31%) as a
1
colorless oil. H NMR δ 3.56 (dd, J = 2.1 Hz, J = 10.3 Hz, Ha-6α), 3.60-3.80 (m, H-2α, Hb-6α, H-2β,
H-3β, H-4β, H-5β, Ha-6β, Hb-6β), 3.79 (dd, J = 8.9 Hz, J = 10.3 Hz, H-4α), 3.87-3.89 (m, H-5α), 4.21
13
(dd, J = 8.9 Hz, J = 9.4 Hz, H-3α), 5.01 (d, J = 7.6 Hz, H-1β), 5.48 (d, J = 3.4 Hz, H-1α); C NMR δ
68.2, 68.8, 70.8, 73.3, 73.4, 73.5, 75.02, 75.05, 75.11, 75.77, 75.78, 77.4, 77.7, 79.7, 82.0, 84.7, 95.4
(C-1α), 101.6 (C-1β); HRMS (ESI, α/β mixture) m/z calcd for 639.2717 (C40H40O6+Na+), found
1
13
1
639.2693. (Lit.,16 α anomer: H NMR δ 5.48 (J = 3.4 Hz, H-1); C NMR δ 95.4 (C-1); β anomer: H
NMR δ 5.01 (J = 7.6 Hz, H-1); 13C NMR δ 101.6 (C-1)).
1-Adamantyl 2,3,4,6-Tetra-O-benzyl-D-glucopyranoside (22) (Table 1, Entry 12): The same
procedure used for the preparation of 13 using Bi(OTf)3 (5.6 mg, 0.0085 mmol), 11 (27.1 mg, 0.18 mmol),
and 1 (89.9 mg, 0.17 mmol) in CH2Cl2 (3 mL) gave the desired glycoside 22 (PTLC; EtOAc/hexane = 1/3,
1
65.2 mg, 58%, a mixture of α and β anomers) as a colorless oil and 26 (15.0 mg, 17%). H NMR δ
1.56-2.17 (30H, m, 1-adamantyl), 3.42-3.50 (m, H-2β, H-4β, H-5β), 3.53 (dd, J = 4.1 Hz, J = 9.6 Hz,
H-2α), 3.60-3.67 (m, Ha-6α, H-4α, Ha-6β, H-3β), 3.73 (dd, J = 2.1 Hz, J = 11.0 Hz, Hb-6β), 3.76 (dd, J =
3.4 Hz, J = 10.3 Hz, Hb-6α), 4.00-4.03 (m, H-5α), 4.01 (dd, J = 8.9 Hz, J = 9.6 Hz, H-3α), 4.70 (d, J =
7.6 Hz, H-1β), 5.28 (d, J = 3.4 Hz, H-1α); 13C NMR δ 30.6, 30.7, 36.3, 36.3, 42.4, 42.8, 68.8, 69.5, 69.6,
72.8, 73.3, 73.4, 74.51, 74.54, 74.9, 75.1, 75.3, 75.5, 75.7, 78.1, 78.2, 80.1, 82.1, 82.3, 85.1, 89.8 (C-1α),
96.2 (C-1β); HRMS (ESI, α/β mixture) m/z calcd for 697.3500 (C44H50O6+Na+), found 697.3538.
(Lit.,18 β anomer: 1H NMR δ 4.69 (J = 7.6 Hz, H-1); 13C NMR δ 96.2 (C-1)).
2-Phenylethyl 2,3,4,6-Tetra-O-benzyl-α-D-mannopyranoside (14) (Table 1, Entry 13): The same
procedure used for the preparation of 13 using Bi(OTf)3 (5.7 mg, 0.0087 mmol), 7 (21.3 mg, 0.17 mmol),
and 2 (94.1 mg, 0.17 mmol) in CH2Cl2 (3 mL) gave the desired glycoside 14 (PTLC; EtOAc/hexane = 1/3,
22
82.1 mg, 73%) as a colorless oil and 27 (14.7 mg, 16%) as a colorless oil. [α]D +30.5° (c 4.1, CHCl3);

HETEROCYCLES, Vol. 77, No. 1, 2009
455
1H NMR δ 2.82 (2H, t, J = 6.9 Hz, CH2CH2Ph), 3.57-3.63 (2H, m, CHaHbCH2Ph, H-5), 3.67 (1H, dd, J =
2.1 Hz, J = 11.0 Hz, Ha-6), 3.71-3.74 (2H, m, H-2, Hb-6), 3.84-3.88 (2H, m, CHaHbCH2Ph, H-3), 3.95
(1H, t, J = 9.6 Hz, H-4), 4.84 (1H, d, J = 2.1 Hz, H-1); 13C NMR δ 36.0, 68.1, 69.3, 71.8, 72.1, 72.5, 73.3,
74.7, 74.9, 74.9, 80.0, 97.7 (C-1, JC1-H1 = 168.3 Hz); HRMS (ESI) m/z calcd for 667.3030
(C42H44O6+Na+), found 667.3073.
Octyl 2,3,4,6-Tetra-O-benzyl-D-mannopyranoside (19) (Table 1, Entry 14): The same procedure used
for the preparation of 13 using Bi(OTf)3 (5.3 mg, 0.0081 mmol), 8 (21.1 mg, 0.16 mmol), and 2 (87.3 mg,
0.16 mmol) in CH2Cl2 (3 mL) gave the desired glycoside 19 (PTLC; EtOAc/hexane = 1/3, 84.9 mg, 81%,
a mixture of α and β anomers) as a colorless oil and 27 (13.5 mg, 16%). 1H NMR δ 0.88 (t, J = 6.9 Hz,
CH3α), 1.26-1.52 (m, CH2(CH2)6CH3), 3.35 (ddd, J = 2.8 Hz, J = 6.9 Hz, J = 9.6 Hz, CHaHb(CH2)6CH3α),
3.65 (ddd, J = 2.8 Hz, J = 6.9 Hz, J = 9.6 Hz, CHaHb(CH2)6CH3α), 3.72-3.80 (m, H-2α, H-5α, Ha-6α,
Hb-6α), 3.91 (dd, J = 3.4 Hz, J = 9.6 Hz, H-3α), 3.99 (t, J = 9.6 Hz, H-4α), 4.37 (d, J = 0.7 Hz, H-1β),
13
4.86 (d, J = 1.4 Hz, H-1α); C NMR δ 14.1, 14.5, 22.61, 22.63, 26.08, 26.12, 29.16, 29.24, 29.3, 29.4,
29.7, 31.8, 67.6, 69.3, 69.7, 70.0, 71.3, 71.7, 72.1, 72.5, 73.3, 73.4, 73.5, 73.6, 74.8, 74.9, 75.0, 75.1, 75.9,
80.3, 82.3, 97.8 (C-1α, JC1-H1 = 165.7 Hz), 101.7 (C-1β, JC1-H1 = 152.6 Hz); HRMS (ESI, α/β mixture)
m/z calcd for 675.3656 (C42H52O6+Na+), found 675.3663. (Lit.,19 α anomer: 1H NMR δ 4.86 (J = 2.1 Hz,
H-1); 13C NMR δ 97.8 (C-1)).
2-Phenylethyl 2,3,4,6-Tetra-O-benzyl-D-galacutopyranoside (15) (Table 1, Entry 15): The same
procedure used for the preparation of 13 using Bi(OTf)3 (4.6 mg, 0.007 mmol), 7 (17.1 mg, 0.14 mmol),
and 3 (75.9 mg, 0.14 mmol) in CH2Cl2 (3 mL) gave the desired glycoside 15 (PTLC; EtOAc/hexane = 1/3,
63.6 mg, 70%, a mixture of α and β anomers) as a colorless oil and 28 (7.6 mg, 10%) as a colorless oil.
1H NMR δ 2.91-2.97 (m, CH2CH2Ph), 3.92 (dd, J = 2.8 Hz, J = 9.6 Hz, H-3α), 4.03 (dd, J = 3.4 Hz, J =
9.6 Hz, H-2α), 4.15-4.19 (m, CHaHbCH2Phβ), 4.37 (d, J = 7.6 Hz, H-1β), 4.83 (d, J = 3.4 Hz, H-1α); 13C
NMR δ 36.0, 36.2, 68.6, 68.8, 68.9, 69.2, 70.5, 73.0, 73.1, 73.2, 73.30, 73.36, 73.39, 73.5, 74.4, 74.7, 75.0,
75.1, 76.5, 78.8, 79.5, 82.1, 97.4 (C-1α), 103.9 (C-1β); HRMS (ESI, α/β mixture) m/z calcd for 667.3030
(C42H44O6+Na+), found 667.3011.
2-Phenylethyl 2-Azido-3,4,6-tri-O-benzyl-2-deoxy-D-glucopyranoside (16) (Table 1, Entry 16): The
same procedure used for the preparation of 13 using Bi(OTf)3 (6.8 mg, 0.01 mmol), 7 (24 μL, 0.2 mmol),
and 4 (95.2 mg, 0.2 mmol) in CH2Cl2 (3 mL) gave the desired glycoside 16 (PTLC; EtOAc/hexane = 1/3,
59.5 mg, 51%, a mixture of α and β anomers) as a colorless oil and 29 (31.2 mg, 33%) as a colorless oil.
1H NMR δ 2.92-2.99 (4H, m, CH2CH2Ph), 3.34 (dd, J = 3.4 Hz, J = 10.3 Hz, H-2α), 3.84-3.88 (m,

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CHaHbCH2Phα), 3.95 (t, J = 9.6 Hz, H-3α), 4.12-4.16 (m, CHaHbCH2Phβ), 4.27 (d, J = 7.6 Hz, H-1β),
4.93 (d, J = 3.4 Hz, H-1α); 13C NMR δ 36.0, 36.2, 63.3, 66.4, 68.2, 68.6, 68.9, 70.6, 70.9, 73.4, 73.5, 74.8,
75.0, 75.3, 75.5, 77.7, 78.2, 80.1, 83.1, 97.6 (C-1α), 102.1 (C-1β); HRMS (ESI, α/β mixture) m/z calcd
for 602.2625 (C35H37O5N3+Na+), found 602.2668.
2-Phenylethyl 2,3,5-Tri-O-benzyl-D-arabinofuranoside (17) (Table 1, Entry 17): The same procedure
used for the preparation of 13 using Bi(OTf)3 (7.9 mg, 0.012 mmol), 7 (29.3 mg, 0.24 mmol), and 6
(101.2 mg, 0.24 mmol) in CH2Cl2 (3 mL) gave the desired glycoside 17 (PTLC; EtOAc/hexane = 1/3,
102.6 mg, 81%, a mixture of α and β anomers) as a colorless oil and 30 (4.5 mg, 5%) as a colorless oil.
1H NMR δ 2.86 (t, J = 6.9 Hz, CH2CH2Phβ), 2.90 (t, J = 6.9 Hz, CH2CH2Phα), 3.42 (d, J = 6.2 Hz, Ha-5β,
Hb-5β), 3.57 (dd, J = 5.5 Hz, J = 11.0 Hz, Ha-5α), 3.57 (ddd, J = 2.8 Hz, J = 6.9 Hz, J = 10.3 Hz,
CHaHbCH2Phβ), 3.61-3.66 (m, CHaHbCH2Phα, Hb-5α), 3.87 (ddd, J = 2.8 Hz, J = 6.9 Hz, J = 9.6 Hz,
CHaHbCH2Phβ), 3.91 (dd, J = 2.8 Hz, J = 6.9 Hz, H-3α), 3.97 (ddd, J = 2.8 Hz, J = 6.9 Hz, J = 9.6 Hz,
CHaHbCH2Phα), 4.00 (d, J = 2.1 Hz, H-2α), 4.03 (dd, J = 4.1, 6.9 Hz, H-2β), 4.07-4.11 (m, H-3β, H-4β),
4.13-4.16 (m, H-4α), 4.86 (d, J = 4.1 Hz, H-1β), 5.02 (s, H-1α); 13C NMR δ 36.0, 36.1, 68.3, 68.4, 69.6,
71.8, 72.0, 72.25, 72.28, 72.5, 73.2, 73.3, 80.2, 80.4, 83.3, 83.4, 84.2, 88.3, 100.4 (C-1β), 106.2 (C-1α);
HRMS (ESI, α/β mixture) m/z calcd for 547.2455 (C34H36O5+Na+), found 547.2446. A part of α anomer
was isolated. α Anomer: [α] D25 +46.6° (c 4.1, CHCl3).
1,6-Anhydro-2,3,4-tri-O-benzyl-β-D-glucopyranose (24) (Table 1, Entry 18): The same procedure
used for the preparation of 13 using Bi(OTf)3 (6.8 mg, 0.01 mmol) and 5 (93.4 mg, 0.21 mmol) in CH2Cl2
22
(3 mL) gave 24 (PTLC; EtOAc/hexane = 1/2, 65.5 mg, 73%) as white crystals. [α] D -30.6° (c 1,
CHCl3); 1H NMR δ 3.34 (1H, s, H-2 or H-3), 3.35 (1H, s, H-2 or H-3), 3.59 (1H, s, H-4), 3.67 (1H, dd, J
= 6.2 Hz, J = 6.9 Hz, Ha-6), 3.90 (1H, d, J = 6.9 Hz, Hb-6), 4.54-4.60 (1H, m, H-5), 5.46 (1H, s, H-1); 13C
NMR δ 65.3, 71.1, 71.7, 71.9, 74.3, 76.0, 76.1, 76.8, 100.6 (C-1); HRMS (ESI) m/z calcd for 455.1829
(C27H28O5+Na+), found 455.1858. (Lit.,20 [α] D20 -29.5° (c 1, CHCl3); Lit.,21 1H NMR δ 5.45 (bs, H-1)).
Allyl 2,3,4-Tri-O-benzyl-D-glucopyranoside (25) (Table 1, Entry 19): The same procedure used for the
preparation of 13 using Bi(OTf)3 (22.5 mg, 0.034 mmol), 12 (117.1 μL, 1.7 mmol), and 5 (77.4 mg, 0.17
mmol) in CH2Cl2 (3 mL) gave 25α (PTLC; EtOAc/hexane = 1/2, 43.1 mg, 51%) as a colorless oil, 25β
25
(22.9 mg, 27%) as a colorless oil, and 24 (12.2 mg, 16%) as a colorless oil. Compound 25α: [α] D
+46.6° (c 4.1, CHCl3); 1H NMR δ 3.51 (1H, dd, J = 3.4 Hz, J = 9.6 Hz, H-2), 3.54 (1H, dd, J = 8.9 Hz, J
= 9.6 Hz, H-4), 3.67-3.72 (2H, m, H-5, Ha-6), 3.74-3.77 (1H, m, Hb-6), 3.97-4.00 (1H, m,
CHaHbCH=CH2), 4.04 (1H, dd, J = 8.9 Hz, J = 9.6 Hz, H-3), 4.14 (1H, dd, J = 5.5 Hz, J = 13.6 Hz,

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CHaHbCH=CH2), 4.77 (1H, d, J = 3.4 Hz, H-1), 5.22 (1H, dd, J = 1.4 Hz, J = 10.3 Hz, CH2CH=CHaHb),
13
5.31 (1H, dd, J = 1.4 Hz, J = 17.2 Hz, CH2CH=CHaHb), 5.92 (1H, m, CH2CH=CH2); C NMR δ 61.8,
68.2, 70.8, 73.2, 75.0, 75.7, 77.4, 80.0, 81.9, 95.6 (C-1), 118.2, 133.6; HRMS (ESI) m/z calcd for
22
1
513.2248 (C30H34O6+Na+), found 513.2293. Compound 25β: [α] D +4.5° (c 1.2, CHCl3); H NMR δ
3.35-3.37 (1H, m, H-5), 3.45 (1H, dd, J = 8.3 Hz, J = 8.9 Hz, H-2), 3.57 (1H, t, J = 9.6 Hz, H-4), 3.67
(1H, dd, J = 8.9 Hz, J = 9.6 Hz, H-3), 3.70-3.73 (1H, m, Ha-6), 3.85-3.88 (1H, m, Hb-6), 4.16 (1H, dd, J =
6.2 Hz, J = 13.1 Hz, CHaHbCH=CH2), 4.40 (1H, dd, J = 5.5 Hz, J = 13.1 Hz, CHaHbCH=CH2), 4.50 (1H,
d, J = 7.6 Hz, H-1), 5.22 (1H, dd, J = 1.4 Hz, J = 10.3 Hz, CH2CH=CHaHb), 5.35 (1H, dd, J = 2.1 Hz, J =
13
17.1 Hz, CH2CH=CHaHb), 5.96 (1H, m, CH2CH=CH2); C NMR δ 62.0, 70.7, 74.97, 75.01, 75.1, 75.7,
77.5, 82.3, 84.5, 102.8 (C-1), 117.5, 133.87; HRMS (ESI) m/z calcd for 513.2248 (C30H34O6+Na+), found
513.2253.
2,3,4,6-Tetra-O-benzyl-D-glucopyranosyl 2,3,4,6-Tetra-O-benzyl-D-glucopyranoside (26) (Table 2,
Entry 4): To a stirred solution of Bi(OTf)3 (8.3 mg, 0.013 mmol) in CH2Cl2 (3 mL) was added 1 (68.4
mg, 0.13 mmol) in the presence of anhydrous CaSO4 (ca. 100 mg) under an Ar atmosphere. The resulting
mixture was stirred at rt for 1 d. The same procedure used for the preparation of 13 was followed. The
crude product was purified using a preparative silica gel TLC (EtOAc/hexane = 1/3) to provide the
desired 1,1’-disaccharide 26 (57.0 mg, 85%, a mixture of αα, αβ, and ββ isomers) as a colorless oil. 1H
NMR δ 3.36-3.38 (m, Ha-6αα), 3.48-3.54 (m, Hb-6αα, H-2αβ-β, H-5ββ), 3.53 (dd, J = 7.6 Hz, J = 8.2 Hz,
H-2ββ), 3.57-3.65 (2H, m, H-2αα, H-2αβ-α), 3.68 (1H, t, J = 9.6 Hz, H-4αα), 3.76 (dd, J = 7.6 Hz, J =
10.3 Hz, H-4αβ-α), 4.02 (1H, dd, J = 8.9 Hz, J = 9.6 Hz, H-3αα-α), 4.09 (1H, t, J = 9.6 Hz, H-3αβ-α),
4.15-4.17 (1H, m, H-5αα-α), 4.58 (1H, d, J = 7.6 Hz, H-1αβ-β), 4.90 (d, J = 8.2 Hz, H-1ββ), 5.16 (1H, d,
J = 3.4 Hz, H-1αβ-α), 5.23 (1H, d, J = 3.4 Hz, H-1αα-α); 13C NMR δ 68.1, 68.9, 70.6, 73.5, 74.6, 74.97,
75.03, 75.6, 77.6, 77.7, 79.3, 81.7, 81.9, 82.2, 84.6, 94.4 (C-1αα), 99.3 (C-1ββ), 99.4 (C-1αβ-α), 104.1
(C-1αβ-β); HRMS (ESI, isomer mixture) m/z calcd for 1085.4810 (C68H70O11+Na+), found 1085.4798. A
part of ββ isomer was isolated. ββ Isomer: [α] D20 +15.9° (c 0.42, CHCl3). (Lit.,22 αα isomer: 13C NMR δ
94.26 (C-1); αβ isomer: 13C NMR δ 99.54 (C-1α), 104.27 (C-1β)).
2,3,4,6-Tetra-O-benzyl-α-D-mannopyranosyl 2,3,4,6-Tetra-O-benzyl-α-D-mannopyranoside (27)
(Table 2, Entry 9): A similar procedure as employed for the preparation of 26 by stirring both Bi(OTf)3
(12.5 mg, 0.019 mmol) and 2 (103.2 mg, 0.19 mmol) in CH2Cl2 (3 mL) at rt for 1 h gave the desired
1,1’-disaccharide 27 (PTLC; EtOAc/hexane = 1/3, 86.0 mg, 85%) as a colorless oil. [α] D25 +30.2° (c 0.88,
CHCl3); 1H NMR δ 3.53-3.56 (2H, m, H-5), 3.60 (2H, dd, J = 2.1 Hz, J = 3.4 Hz, H-2), 3.63 (2H, dd, J =
2.1 Hz, J = 11.0 Hz, Ha-6), 3.69-3.72 (4H, m, Hb-6, H-3), 3.97 (2H, dd, J = 9.6 Hz, J = 10.3 Hz, H-4),

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13
5.20 (2H, d, J = 2.1 Hz, H-1); C NMR δ 69.0, 72.1, 72.4, 72.6, 73.5, 74.0, 74.6, 75.3, 79.5, 93.3 (C-1,
JC1-H1 = 167.5 Hz); HRMS (ESI) m/z calcd for 1085.4810 (C68H70O11+Na+), found 1085.4823. (Lit.,22 [α]
20 +40° (c 0.85, CHCl3); 13C NMR δ 93.25 (C-1)).
D
2,3,4,6-Tetra-O-benzyl-D-galactopyranosyl 2,3,4,6-Tetra-O-benzyl-D-galactopyranoside (28) (Table
2, Entry 10): A similar procedure as employed for the preparation of 26 by stirring both Bi(OTf)3 (6.4
o
mg, 0.0098 mmol) and 3 (52.9 mg, 0.098 mmol) in CH2Cl2 (3 mL) at 0 C for 1 d gave the desired
1,1’-disaccharide 28 (PTLC; EtOAc/hexane = 1/3, 36.3 mg, 70%, a mixture of αα and αβ isomers) as a
colorless oil. 1H NMR δ 4.54 (1H, d, J = 7.6 Hz, H-1αβ-β), 5.20 (1H, d, J = 3.4 Hz, H-1αβ-α), 5.28 (2H,
d, J = 4.1 Hz, H-1αα); 13C NMR δ 93.5 (C-1αα), 99.8 (C-1αβ-α), 103.7 (C-1αβ-β); HRMS (ESI, isomer
mixture) m/z calcd for 1085.4810 (C68H70O11+Na+), found 1085.4816. A part of αα isomer was isolated.
αα Isomer: [α] D21 +74.5° (c 0.81, CHCl3). (Lit.,22 αα isomer: [α] D20 +147.7° (c 0.65, CHCl3); 13C NMR
δ 93.54 (C-1); αβ isomer: 13C NMR δ 99.86 (C-1α), 103.82 (C-1β)).
2-Azido-3,4,6-tri-O-benzyl-2-deoxy-D-glucopyranosyl
2-Azido-3,4,6-tri-O-benzyl-2-deoxy-D-glucopyranoside (29) (Table 2, Entry 13): A similar procedure
as employed for the preparation of 26 by stirring both Bi(OTf)3 (142.5 mg, 0.22 mmol) and 4 (103.8 mg,
0.22 mmol) in CH2Cl2 (3 mL) at rt for 1 d gave the desired 1,1’-disaccharide 29 (PTLC; EtOAc/hexane =
1
1/3, 53.8 mg, 53%, a mixture of αα, αβ, and ββ isomers) as a colorless oil. H NMR δ 4.33 (1H, d, J =
7.56 Hz, H-1αβ-β), 4.72 (1H, d, J = 8.25 Hz, H-1ββ), 5.17 (1H, d, J = 3.44 Hz, H-1αβ-α), 5.21 (1H, d, J
= 3.44 Hz, H-1αα); 13C NMR δ 95.4 (C-1αα), 97.6 (C-1αβ-α), 101.3 (C-1αβ-β), 103.5 (C-1ββ); HRMS
(ESI, isomer mixture) m/z calcd for 955.4001 (C54H56O9N6+Na+), found 955.4026.
2,3,5-Tri-O-benzyl-D-arabinofuranosyl 2,3,5-Tri-O-benzyl-D-arabinofuranoside (30) (Table 2,
Entry 14): A similar procedure as employed for the preparation of 26 by stirring both Bi(OTf)3 (15.8 mg,
o
0.024 mmol) and 5 (101.2 mg, 0.24 mmol) in CH2Cl2 (3 mL) at 0 C for 3.5 h gave the desired
1,1’-disaccharide 30αα (PTLC; EtOAc/hexane = 1/2, 78.2 mg, 79%) as a colorless oil and 30αβ (13.7
mg, 14%) as a colorless oil. αα Isomer: [α] D22 +54.9° (c 3.9, CHCl3); 1H NMR δ 3.61-3.64 (2H, m, Ha-5),
3.65-3.68 (2H, m, Hb-5), 3.94-3.96 (2H, m, H-3), 4.10-4.11 (2H, m, H-2), 4.24-4.27 (2H, m, H-4), 5.50
(2H, s, H-1); 13C NMR δ 69.7, 71.8, 72.1, 73.4, 81.2, 83.7, 87.9, 102.1 (C-1). HRMS (ESI) m/z calcd for
1
25
845.3660 (C52H54O9+Na+), found 845.3686. (Lit.,23 αα isomer: H NMR δ 5.51 (s)). αβ Isomer: [α] D
+18.5° (c 0.69, CHCl3); 1H NMR δ 3.56-3.63 (3H, m, Ha-5α, Hb-5α, Ha-5β), 3.67 (1H, dd, J = 6.2 Hz, J =
10.3 Hz, Hb-5β), 3.99 (1H, dd, J = 2.8 Hz, J = 6.2 Hz, H-3α), 4.10-4.15 (4H, m, H-2α, H-2β, H-3β,
13
H-4β), 4.30-4.32 (1H, m, H-4α), 5.18 (1H, d, J = 3.4 Hz, H-1β), 5.20 (1H, s, H-1α); C NMR δ 69.5

HETEROCYCLES, Vol. 77, No. 1, 2009
459
(C-5α), 71.7 (CH2Ph), 72.1 (CH2Ph), 72.2 (CH2Ph), 72.6 (CH2Ph), 72.7 (C-5β), 73.1 (CH2Ph), 73.3
(CH2Ph), 80.8 (C-4β), 81.4 (C-4α), 83.58 (C-3α), 83.62 (C-2β or C-3β), 84.56 (C-2β or C-3β), 87.8
(C-2α), 99.5 (C-1β), 106.1 (C-1α); HRMS (ESI) m/z calcd for 845.3660 (C52H54O9+Na+), found
845.3659.
2,3,5-Tri-O-benzyl-D-arabinofuranosyl 2,3,4,6-Tetra-O-benzyl-D-glucopyranoside (31) (Table 2,
Entry 15): A similar procedure as employed for the preparation of 26 by stirring Bi(OTf)3 (11.0 mg,
0.017 mmol), 1 (135.7 mg, 0.25 mmol), and 6 (70.5 mg, 0.17 mmol) in CH2Cl2 (3 mL) at 0 oC for 3.5 h
gave the desired 1,1’-disaccharide 31 (PTLC; EtOAc/hexane = 1/4, 117.3 mg, 74%, a mixture of αα, αβ,
1
βα, and ββ (Glc/Ara linkages: 31/31/31/7) isomers) as a colorless oil. H NMR δ 4.62 (d, J = 8.2 Hz,
H-1βα(Glc)), 4.78-4.80 (m, H-1ββ(Glc)), 5.20 (d, J = 3.4 Hz, H-1αβ(Glc)), 5.29 (d, J = 4.2 Hz,
H-1’αβ(Ara)), 5.40 (1H, d, J = 3.4 Hz, H-1αα(Glc)), 5.42(1H, s, H-1’αα(Ara)), 5.43 (s, H-1’βα(Ara)),
5.60(d, J = 3.4 Hz, H-1’ββ(Ara));13C NMR δ 92.7 (C-1αα(Glc)), 96.1 (C-1’ββ(Ara)), 96.2 (C-1αβ(Glc)),
97.5 (C-1ββ(Glc)), 100.6 (C-1’αβ(Ara)), 101.4 (C-1βα(Glc)), 102.0 (C-1’αα(Ara)), 106.6
(C-1’βα(Ara)); HRMS (ESI, isomer mixture) m/z calcd for 965.4235 (C60H62O10+Na+), found 965.4237.
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