Formation of 2-acetamido-2-deoxy-d-glucopyranosidic linkages via glycosidation using a combination of two lewis acids

Article abstract of DOI:10.3987/COM-14-S(K)4

A mixed activation system composed of ytterbium(III) triflate and a catalytic boron trifluoride diethyl etherate complex efficiently promotes the glycosylation of various alcohol acceptors using 2-acetamido-3,4,6-tri-O-benzyl-2-deoxy-α-D-glucopyranosyl ac

Full text of DOI:10.3987/COM-14-S(K)4

HETEROCYCLES, Vol. 90, No. 1, 2014, pp. -. © 2014 The Japan Institute of Heterocyclic Chemistry
Received, 27th January, 2014, Accepted, 17th March, 2014, Published online, 26th March, 2014
DOI: 10.3987/COM-14-S(K)4
FORMATION OF 2-ACETAMIDO-2-DEOXY-D-GLUCOPYRANOSIDIC
LINKAGES VIA GLYCOSIDATION USING A COMBINATION OF TWO
LEWIS ACIDS†
Yoshiki Oda, Masanobu Midorikawa, and Takashi Yamanoi*
The Noguchi Institute, 1-8-1 Kaga, Itabashi-ku, Tokyo 173-0003, Japan
†Dedicated to Professor Dr. Isao Kuwajima on his 77th birthday.
Abstract – A mixed activation system composed of ytterbium(III) triflate and a
catalytic boron trifluoride diethyl etherate complex efficiently promotes the
glycosylation
2-acetamido-3,4,6-tri-O-benzyl-2-deoxy-α-D-glucopyranosyl
dichloromethane at room temperature
of
various
alcohol
acceptors
acetate
to
using
in
afford
2-acetamido-2-deoxy-D-glucopyranosides in good yields with significant
formation of the α-isomers. Notably, stereoselective glycosylations of phenol
derivatives as the acceptors afforded aryl 1,2-cis-α-glycosides without the
formation of any β-isomers. This highly stereocontrolled 1,2-cis-α-glycosidation
was applied to the synthesis of a novel hydroquinone α-glycoside.
INTRODUCTION
Glycosidation is an indispensable tool for glycoside synthesis; however, identifying appropriate glycosyl
donors and activating agents is a major challenge for the development of glycosidation methods. Lewis
acids are probably the most widely used activators for glycosidation. Among them, ytterbium(III) triflate
(Yb(OTf)3) is known to be a powerful activator for a few glycosidation reactions.1 We previously showed
that Yb(OTf)3 is effective with several glycosyl acetates.2 Several glycosidation methods using a
combination of two Lewis acids such as bismuth(III) triflate-boron trifluroride diethyletherate
(BF3·OEt2),3 silver perchlorate-lithium perchlorate,4 and Yb(OTf)3-zinc chloride5 have been reported. In
addition, we recently showed that a mixed activating system based on Yb(OTf)3 and a catalytic amount of
BF3·OEt2 was useful for glycosidation using certain less reactive glycosyl acetates.6 When our attention
was directed toward glycosidation using 2-acetamido-3,4,6-tri-O-benzyl-2-deoxy-α-D-glucopyranosyl

acetate (1),7 which is a less reactive glycosyl donor, the use of the mixed Yb(OTf)3-BF3·OEt2 activating
system exhibited interesting glycosyl acceptor specificities,8 i.e., the glycosidation using certain aliphatic
alcohols afforded the corresponding 2-acetamido-2-deoxy-D-glucopyranosides with a considerable
amount of formation of the α-isomers, while glycosidations of phenol derivatives proceeded
stereoselectively, affording aryl α-glycosides without the formation of any β-isomers.
The 2-acetamido-2-deoxy-α-D-glucopyranosidic linkage is involved in some glycosidic natural products
such as O-glycans of gastric mucins,9 lipopolysaccharides of bacteria,10 and tunicamycin11,12 Therefore,
the development of a convenient method for the formation of the 1,2-cis-α-glycosidic linkage directly
from 2-acetamido-2-deoxy-D-glucopyranose derivatives is an important goal in synthetic carbohydrate
chemistry.13
Herein,
we
describe
in
detail
the
formation
of
the
2-acetamido-2-deoxy-α-D-glucopyranosidic linkage based on the glycosyl acceptor properties for
glycosidations using 1 with a mixed activation system composed of Yb(OTf)3-BF3·OEt2. To demonstrate
the applicability of the method, the synthesis of a novel hydroquinone α-glycoside was achieved using the
highly stereocontrolled 1,2-cis-aryl-α-glycosidation.
RESULTS AND DISCUSSION
Glycosidation using 1 with the mixed activating system composed of Yb(OTf)3 (1 equiv.)-BF3·OEt2 (0.03
equiv.) was first investigated with phenethyl alcohol (2) as the substrate (Scheme 1). This reaction, which
proceeded in CH2Cl2 overnight at room temperature, gave the desired phenethyl
2-acetamido-3,4,6-tri-O-benzyl-2-deoxy-D-glucopyranoside (3) in a high yield of 95% with an α/β ratio
of 40/60 (Entry 1, Table 1). Interestingly, this reaction resulted in the formation of a considerable amount
of α-glycoside. This finding that the 1,2-cis-α-glycosidic linkage was directly formed from a
2-acetamido-2-deoxy-D-glucopyranosyl donor was very rare. It is known that glycosidations using
2-acetamido-2-deoxy-D-glucopyranosyl donors bearing a natural N-acetyl protecting group typically form
the corresponding β-glycosides via SN2-like nucleophilic substitution of alcohols with in situ generated
oxazoline derivatives (or oxazolinium cation intermediates).14 Therefore, this unusual stereoselectivity of
the glycosidation between 1 and 2 using our mixed activating system suggests that the reaction may
proceed via a different pathway that does not involve the generation of an oxazoline intermediate.
BnO
BnO
BnO
BnO
O
O
O
Yb(OTf)3-Additive
CH2Cl2, rt
BnO
BnO
BnO
BnO
AcHN
BnO
AcHN
+
ROH
OR
3, 17-29
O
N
OAc
1
2, 4-16
30
Scheme 1

Table 1. Reaction of 1(and 30) with aliphatic alcohols (2, 4-11) and phenol derivatives (12-16)a
Entry
1
Donor
Acceptor
Additive
BF3·OEt2
None
Glycoside
Yield (%)
 Ratio
40/60
-
1
1
2
2
3
95
2
3
Trace
3
1
2
TfOH
3
68
47/53
51/49
19/81
49/51
37/63
38/62
23/77
53/47
31/69
35/65
α
4
1
2
AcOH
3
72
5
1
4
BF3·OEt2
BF3·OEt2
BF3·OEt2
BF3·OEt2
BF3·OEt2
BF3·OEt2
BF3·OEt2
BF3·OEt2
BF3·OEt2
BF3·OEt2
BF3·OEt2
BF3·OEt2
BF3·OEt2
BF3·OEt2
BF3·OEt2
17
18
19
20
21
22
23
24
25
26
27
28
29
3
83
6
1
5
86
7
1
6
94
8
1
7
71
9
1
8
70
10
11
12
13
14
15
16
17
18
19
1
9
68
1
10
11
12
13
14
15
16
2
71
1
37
1
67
1
84
α
1
57
α
1
46
60
α
1
α
30
30
53
β
12
25
No reaction
-
aReaction conditions; molar ratio; Donor: Acceptor: Yb(OTf)3: Additive= 1.2: 1: 1: 0.03; overnight; room
temperature.
HO
HO
HO
HO
HO
OBn
HO
HO
2
4
5
6
7
8
9
HO
BnO
HO
HO
HO
HO
HO
HO
O
NHCbz
O
BnO
OMe
OBz
CO2Bn
BnO
OMe
O
10
11
12
13
14
15
16
Figure 1

A catalytic amount of BF3·OEt2 is essential for promoting the glycosidation because the reaction barely
proceeds without added BF3·OEt2 (Entry 2). We speculate that the ROH-BF3 complex formed in situ
between BF3·OEt2 and the alcohol acceptor acts as a Brønsted acid and influences the glycosidation
reactivity.15 The effect of the Brønsted acids, acetic acid (AcOH) and triflic acid (TfOH), as additives was
thus examined (Entries 3 and 4). The addition of 3 mol% of AcOH and TfOH to the glycosidation
reaction using 1 (1.2 equiv.), phenethyl alcohol (1 equiv.), and Yb(OTf)3 (1 equiv.) in CH2Cl2 at room
temperature produced 3 in 72% and 68% yield with α/β ratios of 49/51 and 47/53, respectively. The
addition of AcOH and TfOH was also effective for the promotion of glycosidations using 1 and BF3·OEt2,
and these reactions also afforded a considerable amount of the α-glycoside.
Next, we investigated the glycosidation of several types of alcohols under similar reaction conditions
using 1 in order to examine the effect of the acceptor on the stereoselectivity of the reaction. Primary and
secondary alkyl alcohols 2, 4–11 gave the corresponding glycosides 3, 17–24, respectively, in good yields
with α/β ratios of ca. 1/1–1/5 (Entries 1 and 5–12, Table 1). Thus, each of these reactions gave a mixture
of α- and β-glycosides. However, surprisingly, the reactions using phenol derivatives 12–16 gave aryl
α-glycosides 25–29, respectively, in good yields with no formation of the β-glycosides (Entries 13–17).
The steric and electronic effects of the phenol derivatives may strongly influence the α-stereoselectivity
of the reaction. The configuration of the glycosidic bond of these glycosides was determined based on the
coupling constant values in their 1H-NMR spectra (α form: J = 3.3–4.1 Hz; β form: J = 7.2–8.4 Hz).
In addition, we confirmed that the β-anomer of 25 was not isomerized to the α-anomer under acidic
conditions in the presence of Yb(OTf)3 (1 equiv.) and BF3·OEt2 (0.03 equiv.) in CH2Cl2 at room
temperature. Therefore, the α-glycosides formed in the glycosidation using 1 are not conversion products
of in situ acid-catalyzed anomerization of the β-glycosides.
Furthermore, to clarify the difference in the reaction mechanism, we performed glycosidations using
3,4,6-tri-O-benzyl-1,2-oxazoline-glucopyranose (30),16 which appeared to at least partially proceed via an
in situ generated intermediate under the same conditions (see Table 2). The reaction of 30 (1.2 equiv.)
with 2 and 12 was examined in the presence of Yb(OTf)3 (1 equiv.) and BF3·OEt2 (0.03 equiv.) in CH2Cl2
at room temperature. Acceptor 2 afforded the corresponding β-glycoside in 53% yield with no formation
of the α-glycoside (Entry 18), while phenol (12) did not react at all (Entry 19). Thus, the reactivity and
stereoselectivity of the glycosidation using 30 were found to be quite different from those of the
glycosidation using 1.
We speculate that the complexation of ytterbium metal to the carbonyl group of 1 may generate a
glycosyl cation intermediate, as shown in Scheme 2. Formation of this complex would prevent the
generation of the oxazoline derivative because of the decrease in the Lewis basicity of the oxygen atom of
the carbonyl group, thus allowing the alcohol to attack the glycosyl cation intermediate from the α-face to

form the 1,2-cis-α-glycosidic linkage.17 The formation of 1,2-trans-β-glycosides during the glycosidation
using alkyl alcohols can be explained by the β-attack of the alcohol on the glycosyl cation intermediate or
the in situ generated oxazoline derivative. However, we have not yet found a sufficient explanation for
the high α-stereoselectivities of the glycosidations using phenol derivatives.
BnO
OR
O
BnO
BnO
AcHN
-Glycoside
BnO
BnO
BnO
HOR
HOR'
HOR
+
O
BnO
O
BnO
BnO
1
O
HN
C
N
Yb
Ln
O
Me
BnO
Oxazoline derivative
Glycosyl intermediate
O
BnO
BnO
AcHN
R= Alkyl
OR'
-Glycoside
R'= Alkyl or Aryl
Scheme 2
Finally, the 1,2-cis-α-aryl-D-glycosidation method was applied to the synthesis of the novel hydroquinone
α-glycoside 4-hydroxyphenyl 2-acetamido-2-deoxy-α-D-glucopyranoside (31)18; 31 is an analogue of
arbutin (4-hydroxyphenyl D-glucopyranoside) (32), which exhibits inhibitory activity against tyrosinase, a
key enzyme for the synthesis of melanin, the overproduction of which results in hyperpigmentation in the
epidermis. Notably, the α-anomeric isomer of 32 has stronger inhibitory activity against mammalian
tyrosinases than the β-anomeric isomer.19 As a result, the synthesis of α-arbutin analogues and the
investigation of their performance as skin-lightening agents has recently attracted attention.20
Hydroquinone (33) has been utilized as a glycosyl acceptor for the preparation of several hydroquinone
glycosides using both enzymatic and chemical glycosylation methods.21 We conducted a detailed
investigation of the glycosidation of 33 using 1, including evaluation of the by-products formed in the
reaction (Scheme 3). When the Yb(OTf)3 (1 equiv.)-BF3·OEt2 (0.03 equiv.) mixed activating system was
used in CH2Cl2 for 1 h at room temperature, the desired hydroquinone α-glycoside 35 was obtained in
only 18% yield. However, the production of its β-anomer isomer was not observed at all. Further, 1 was
recovered in 45% yield, and 30 was produced in 15% yield (Entry 1, Table 2). These results suggested
that the low yield was due to the poor solubility of 33 in CH2Cl2. However, when the reaction was run in
a mixed CH2Cl2/Et2O (v/v= 1/1) solvent in which 33 was soluble, only a trace amount of the desired 35
was formed (Entry 2). Thus, the use of Et2O inhibited the glycosylation.

Next, 4-tert-butoxyphenol (34) was utilized as the glycosyl acceptor; 34 was observed to be moderately
soluble in CH2Cl2, and the Lewis acid glycosylation promoter was expected to cleave the tert-butyl group
during the reaction. Rewardingly, the desired 35 was obtained in 66% yield using Yb(OTf)3 (1
equiv.)-BF3·OEt2 (0.03 equiv.) in CH2Cl2 for 1 h at room temperature (Entry 3). Interestingly, the
glycoside 36 with the tert-butyl group retained was also obtained in 8% yield. Thus, the total yield of the
glycoside products in this reaction reached 74%. In addition, 30 was formed in 21% yield. When the
reaction was allowed to proceed for 6 h, no 36 remained; however, 30 and 37 were produced as
byproducts in 22% and 10% yields, respectively (Entry 4). The deprotection of the benzyl groups of 35
using Pd(OH)2 in THF-MeOH yielded an excellent quantity of desired 31.
HO
HO
HO
O
O
HO
HO
HO
AcHN
HO
O
OH
O
OH
-Arbutin: 32
-Arbutin analogue: 31
Pd(OH)2/
THF-MeOH
93%
BnO
BnO
BnO
.
Yb(OTf)3-cat. BF3 OEt2
O
O
BnO
+
1
HO
OR
BnO
BnO
AcHN
+
CH2Cl2, rt
AcHN
OBut
O
O
OH
R = H: 33; But: 34
35
36
Scheme 3
Table 2. Preparation of hydroquinone α-glycoside 31 via glycosylation of 33 and 34 using 1
Product (%)
Entrya
Acceptor
Time (h)
35
18
36
-
30
15
-
37
trace
-
1b
2c
3
33
33
34
34
1
1
1
6
trace
66
-
8
-
21
22
-
4
52
10
a Molar ratio; 1: Acceptor: Yb(OTf)3: BF3·OEt2= 1.2: 1: 1: 0.03. Solvent; CH2Cl2. Temperature; room temperature.
b 45% of 1 was recovered.
c Solvent; CH2Cl2: Et2O= 1:1.
BnO
O
BnO
BnO
AcHN
OH
37

In summary, several 2-acetamido-2-deoxy-D-glucopyranosides were directly synthesized from glycosyl
acetate 1 in good yields with the formation of a considerable amount of α-isomers using a
Yb(OTf)3-catalytic BF3·OEt2 mixed activating system. Notably, reactions of phenol derivatives as
acceptors only afforded aryl α-glycosides, with no formation of β-glycosides. The synthesis of the novel
hydroquinone 2-acetamido-2-deoxy-α-D-glucopyranoside as an α-arbutin analogue was also successfully
achieved using the highly stereocontrolled 1,2-cis-α-aryl-D-glycosidation method.
EXPERIMENTAL
1H-NMR (600 MHz) and 13C-NMR (150 MHz) spectra were recorded using a JEOL ECA-600
spectrometer. Melting points were determined using B-545 (BÜCHI Labortechnik AG) and are
uncorrected. Optical rotations were recorded using a JASCO DIP-360 digital polarimeter. Preparative
TLC was performed on Merck silica gel 60GF254. Column chromatography was conducted using silica
gel 60N (40–50 μm, Kanto Chemical Co. Inc.). All anhydrous solvents were purified according to
standard methods.
Typical glycosidation procedure
Yb(OTf)3 (98.2 mg, 0.2 mmol) was added to a solution of 1 (101.4 mg, 0.2 mmol), 2 (19.34 mg, 0.2
mmol), and BF3·OEt2 (47 μL, 0.005 mmol) in CH2Cl2 (3 mL) at 0 °C, and the resulting mixture was
stirred for 16 h at room temperature. The reaction was then quenched by the addition of sat. aq. NaHCO3
solution (5 mL), and the reaction mixture was extracted with CH2Cl2. The organic layer was then washed
with water and sat. aq. NaCl solution and dried over Na2SO4, the solvent. The crude product obtained
after evaporation of the solvent under reduced pressure was purified via preparative silica gel TLC
(EtOAc/hexane = 2/1) to give 3 (95% yield, α form; 35.7 mg, β form; 53.7 mg, α/β ratio = 40/60) as white
crystals.
Phenethyl 2-Acetamido-3,4,6-tri-O-benzyl-2-deoxy-D-glucopyranoside (3)
1
α Form; Rf 0.48 (EtOAc/hexane = 2/1); mp 152.5–154.5 °C; [α]25 +72.5 (c 1.0, CHCl3); H NMR (600
D
MHz, CDCl3): δ 1.62 (3H, s, CH3), 2.84 (2H, m, CH2CH2Ph), 3.35 (1H, dt, J = 6.7 Hz, J = 8.9 Hz,
CHaHbCH2Ph), 3.63–3.65 (2H, m, H-3, Ha-6), 3.69–3.72 (3H, m, H-4, H-5, Hb-6), 3.94 (1H, dt, J = 5.7
Hz, J = 9.6 Hz, CHaHbCH2Ph), 4.18 (1H, dt, J = 3.6 Hz, J = 10.0 Hz, H-2), 4.35–4.84 (6H, m, CH2Ph),
4.68 (1H, d, J = 3.6 Hz, H-1), 4.93 (1H, d, J = 9.5 Hz, NH), 7.10–7.31 (20H, m, Ph); 13C NMR (150 MHz,
CDCl3): δ 23.3 (CH3), 35.8 (CH2CH2Ph), 52.3 (C-2), 68.2 (CH2CH2Ph), 68.5 (C-6), 71.0 (C-5), 73.4–74.9
(CH2Ph), 78.3 (C-4), 80.1 (C-3), 97.7 (C-1), 126.3 (Ph), 127.6-128.8 (Ph), 128.8 (Ph), 138.9 (Ph), 169.6
(C=O), 138.0–138.4 (Ph); HRMS (ESI): m/z calcd for C37H41NO6Na+: 618.2826; found: 618.2828. β

1
Form; Rf 0.65 (EtOAc/hexane = 2/1); mp 154.7–157.5 °C; [α]25 +10.3 (c 1.0, CHCl3); H NMR (600
D
MHz, CDCl3): δ 1.73 (3H, s, CH3), 2.87 (2H, m, CH2CH2Ph), 3.44 (1H, m, H-2), 3.56 (1H, m, H-5), 3.62
(1H, t, J = 8.9 Hz, H-4), 3.65–3.75 (3H, m, H-6, CHaHbCH2Ph), 4.05 (1H, t, J = 8.9 Hz, H-3), 4.10 (1H,
dt, J = 6.5 Hz, J = 8.9 Hz, CHaHbCH2Ph), 4.51–4.80 (6H, m, CH2Ph), 4.76 (1H, d, J = 7.6 Hz, H-1), 5.45
13
(1H, d, J = 7.6 Hz, NH), 7.18–7.33 (20H, m, Ph); C NMR (150 MHz, CDCl3): δ 23.5 (CH3), 36.0
(CH2CH2Ph), 56.7 (C-2), 69.0 (C-6), 70.0 (CH2CH2Ph), 73.4–74.5 (CH2Ph), 74.7 (C-5), 78.5 (C-4), 80.4
(C-3), 99.8 (C-1), 126.1 (Ph), 127.6-128.7 (Ph), 129.0 (Ph), 138.8 (Ph), 170.2 (C=O), 138.0-138.4 (Ph);
HRMS (ESI): m/z calcd for C37H41NO6Na+: 618.2826; found: 648.2823.
Propyl 2-Acetamido-3,4,6-tri-O-benzyl-2-deoxy-D-glucopyranoside (17)
Using the same procedure as described above for 3, Yb(OTf)3 (123.3 mg, 0.2 mmol) was added to a
solution of 1 (127.3 mg, 0.2 mmol), 4 (12.0 mg, 0.2 mmol), and BF3·OEt2 (60 μL, 0.006 mmol) in
CH2Cl2 (3 mL) to give 17 (PTLC; EtOAc/hexane = 2/1, 95% yield, α form; 16.9 mg, β form; 71.5 mg, α/β
ratio = 19/81) as white crystals. α Form; Rf 0.50 (EtOAc/hexane = 2/1); mp 142.0–142.1 °C; [α]26
D
1
+102.7 (c 0.34, CHCl3); H NMR (600 MHz, CDCl3): δ 0.90 (3H, t, J = 7.4 Hz, CH2CH3), 1.57 (2H, m,
CH2CH3), 1.84 (3H, s, CH3), 3.34 (1H, dt, J = 6.6 Hz, J = 9.8 Hz, CHaHbCH2CH3), 3.61 (1H, dt, J = 6.8
Hz, J = 9.6 Hz, CHaHbCH2CH3), 3.68 (1H, dd, J = 1.5 Hz, J = 10.4 Hz, Ha-6), 3.69 (1H, t, J = 9.5 Hz,
H-3), 3.70 (1H, t, J = 9.2 Hz, H-4), 3.78 (1H, dd, J = 1.8 Hz, J = 11.3 Hz, Hb-6), 3.79 (1H, m, H-5), 4.26
(1H, dt, J = 3.7 Hz, J = 9.9 Hz, H-2), 4.51–4.86 (6H, m, CH2Ph), 4.78 (1H, d, J = 3.6 Hz, H-1), 5.28 (1H,
13
d, J = 9.5 Hz, NH), 7.17-7.35 (15H, m, Ph); C NMR (150 MHz, CDCl3): δ 10.6 (CH2CH3), 22.7
(CH2CH3), 23.5 (CH3), 52.6 (C-2), 68.6 (C-6), 69.4 (CH2CH2CH3), 71.0 (C-5), 73.5–75.1 (CH2Ph), 78.5
(C-4), 80.5 (C-3), 97.5 (C-1), 127.6–128.5 (Ph), 138.1-138.5 (Ph), 169.6 (C=O); HRMS (ESI): m/z calcd
for C32H39NO6Na+: 556.2670; found: 556.2668. β Form; Rf 0.57 (EtOAc/hexane = 2/1); mp
1
138.2–138.4 °C; [α]26 +25.7 (c 1.1, CHCl3); H NMR (600 MHz, CDCl3): δ 0.89 (3H, t, J = 7.5 Hz,
D
CH2CH3), 1.58 (2H, m, CH2CH3), 1.85 (3H, s, CH3), 3.38 (1H, q, J = 8.2 Hz, H-2), 3.42 (1H, dt, J = 6.8
Hz, J = 9.1 Hz, CHaHbCH2CH3), 3.59 (1H, m, H-5), 3.62 (1H, t, J = 8.6 Hz, H-4), 3.71 (1H, dd, J = 4.7
Hz, J = 10.4 Hz, Ha-6), 3.76 (1H, bd, J = 12.4 Hz, Hb-6), 3.81 (1H, td, J = 6.8 Hz, J= 9.5 Hz,
CHaHbCH2CH3), 4.13 (1H, t, J = 8.9 Hz, H-3), 4.54–4.84 (6H, m, CH2Ph), 4.81 (1H, d, J = 8.4 Hz, H-1),
13
5.58 (1H, d, J = 7.4 Hz, NH), 7.19–7.34 (15H, m, Ph); C NMR (150 MHz, CDCl3): δ 10.4 (CH2CH3),
22.8 (CH2CH3), 23.5 (CH3), 57.1 (C-2), 69.0 (C-6), 71.1 (CH2CH2CH3), 73.4–74.5 (CH2Ph), 74.8 (C-5),
78.7 (C-4), 80.3 (C-3), 99.8 (C-1), 127.5–128.4 (Ph), 138.1-138.5 (Ph), 170.2 (C=O); HRMS (ESI): m/z
calcd for C32H39NO6Na+: 556.2670; found: 556.2708.
Benzyl 2-Acetamido-3,4,6-tri-O-benzyl-2-deoxy-D-glucopyranoside (18)22-24

Using the same procedure as described above for 3, Yb(OTf)3 (125.1 mg, 0.2 mmol) was added to a
solution of 1 (129.0 mg, 0.2 mmol), 5 (22.0 mg, 0.2 mmol), and BF3·OEt2 (60 μL, 0.006 mmol) in
CH2Cl2 (3 mL) to give 18 (PTLC; EtOAc/hexane = 2/1, 86% yield, α form22; 52.1 mg, β form23, 24; 49.6
mg, α/β ratio = 51/49) as white crystals.
Allyl 2-Acetamido-3,4,6-tri-O-benzyl-2-deoxy-D-glucopyranoside (19)25,26
Using the same procedure as described above for 3, Yb(OTf)3 (126.4 mg, 0.2 mmol) was added to a
solution of 1 (130.5 mg, 0.2 mmol), 6 (11.8 mg, 0.2 mmol), and BF3·OEt2 (61 μL, 0.006 mmol) in
CH2Cl2 (3 mL) to give 19 (PTLC; EtOAc/hexane = 2/1, 102.1 mg, 94% yield, α/β ratio = 37/63) as white
1
crystals. α25,26 And β form mixture; Rf 0.58 (EtOAc/hexane = 2/1); H NMR (600 MHz, CDCl3): δ 1.84
(3H, s, α-CH3), 1.85 (3H, s, β-CH3), 3.46 (1H, q, J = 8.4 Hz, β-H-2), 3.59 (1H, dt, J = 2.2 Hz, J = 6.9 Hz,
β-H-5), 3.63–3.78 (7H, m, α-CH2=CHCH2, β-CH2=CHCH2, α-H-3, α-H-4, β-H-4), 3.80 (1H, dd, J = 2.2
Hz, J = 9.7 Hz , α-H-5), 3.94 (1H, dd, J = 6.1 Hz, J = 13.0 Hz, α-Ha-6), 4.06 (1H, dd, J = 6.7 Hz, J = 13.4
Hz, β-Ha-6), 4.10 (1H, t, J = 9.0 Hz, β-H-3), 4.14 (1H, dd, J = 5.2 Hz, J = 12.9 Hz, α-Hb-6), 4.28 (1H, td,
J = 3.7 Hz, J = 9.8 Hz, α-H-2), 4.32 (1H, dd, J = 5.2 Hz, J = 12.9 Hz, β-Hb-6), 4.80 (1H, d, J =3.6 Hz,
α-H-1), 4.50–4.86 (12H, m, CH2Ph), 4.85 (1H, d, J =7.6 Hz, β-H-1), 5.17 (2H, bdd, J = 10.5 Hz, J = 14.4
Hz, α-CHaHb=CHCH2, β-CHaHb=CHCH2), 5.24 (2H, td, J = 0.8 Hz, J = 10.4 Hz, J = 17.2 Hz,
α-CHaHb=CHCH2, β-CHaHb=CHCH2), 5.31 (1H, d, J = 9.5 Hz, α-NH), 5.60 (1H, d, J = 7.7 Hz, β-NH),
13
5.86 (2H, m, α-CH2=CHCH2, β-CH2=CHCH2), 7.17–7.35 (30H, m, Ph); C NMR (150 MHz, CDCl3): δ
23.4 (α-CH3), 23.6 (β-CH3), 52.5 (α-C-2), 56.8 (β-C-2), 68.1 (α-C-6), 68.5 (α-CH2=CHCH2), 69.0 (β-C-6),
69.8 (β-CH2=CHCH2), 71.1 (α-C-5), 73.5–75.1 (CH2Ph), 74.8 (β-C-5), 78.4 (α-C-4), 78.5 (β-C-4), 80.2
(β-C-3), 80.4 (α-C-3), 96.9 (α-C-1), 99.0 (β-C-1), 117.3 (α-CH2=CHCH2), 117.6 (β-CH2=CHCH2),
127.6-128.5 (Ph), 133.7 (α-CH2=CHCH2), 134.1 (β-CH2=CHCH2), 138.0-138.5 (Ph), 169.7 (α-C=O),
170.3 (β-C=O); HRMS (ESI): m/z calcd for C32H37NO6Na+: 554.2513; found: 554.2509.
5-Benzyloxypenthyl 2-Acetamido-3,4,6-tri-O-benzyl-2-deoxy-D-glucopyranoside (20)
Using the above same procedure as described above for 3, Yb(OTf)3 (142.5 mg, 0.2 mmol) was added to
a solution of 1 (147.2 mg, 0.3 mmol), 7 (44.6 mg, 0.2 mmol), and BF3·OEt2 (69 μL, 0.007 mmol) in
CH2Cl2 (3 mL) to give 20 (PTLC; EtOAc/hexane = 2/1, 71% yield, α form; 41.8 mg, β form; 69.5 mg, α/β
ratio = 38/62) as white crystals. α From; Rf 0.48 (EtOAc/hexane = 2/1); mp 84.0–84.8 C; [α]26 +70.0
D
(c 0.64, CHCl3); 1H NMR (600 MHz, CDCl3): δ 1.41 (2H, m, BnOCH2CH2CH2), 1.57 (2H, q, J = 7.4 Hz,
BnOCH2CH2), 1.62 (2H, q, J = 7.1 Hz, BnOCH2CH2CH2CH2), 1.81 (3H, s, CH3), 3.36 (1H, td, J = 6.5 Hz,
J = 9.8 Hz, BnOCH2CH2CH2CH2CHaHb), 3.46 (2H, t, J = 6.5 Hz, BnOCH2), 3.66 (1H, dt, J = 6.4 Hz, J =
9.8 Hz, BnOCH2CH2CH2CH2CHaHb), 3.67 (1H, bd, J = 10.3 Hz, Ha-6), 3.69 (1H, t, J = 10.0 Hz, H-3),

3.74 (1H, t, J = 9.0 Hz, H-4), 3.76 (1H, bd, J = 9.6 Hz, Hb-6), 3.77 (1H, m, H-5), 4.26 (1H, dt, J = 3.7 Hz,
J = 9.9 Hz, H-2), 4.49–4.84 (8H, m, CH2Ph), 4.76 (1H, d, J = 3.8 Hz, H-1), 5.31 (1H, d, J = 9.5 Hz, NH),
13
7.16–7.33 (20H, m, Ph); C NMR (150 MHz, CDCl3): δ 22.9 (BnOCH2CH2CH2), 23.4 (CH3), 29.1
(BnOCH2CH2), 29.4 (BnOCH2CH2CH2CH2), 52.5 (C-2), 67.7 (BnOCH2), 68.6 (C-6), 70.1
(BnOCH2CH2CH2CH2CH2), 70.9 (C-5), 72.9–75.0 (CH2Ph), 78.4 (C-4), 80.5 (C-3), 97.6 (C-1), 127.5–
128.5 (Ph), 138.0-138.5 (Ph), 169.6 (C=O); HRMS (ESI): m/z calcd for C41H49NO7Na+: 690.3401; found:
1
690.3380. β Form; Rf 0.65 (EtOAc/hexane = 2/1); mp 83.2–85.5 °C; [α]26 +10.1 (c 1.0, CHCl3); H
D
NMR (600 MHz, CDCl3): δ 1.41 (2H, q, J = 7.7 Hz, BnOCH2CH2CH2), 1.57 (2H, q, J = 7.3 Hz,
BnOCH2CH2CH2CH2), 1.61 (2H, q, J = 7.1 Hz, BnOCH2CH2), 1.81 (3H, s, CH3), 3.37 (1H, dt, J = 7.9 Hz,
J = 9.6 Hz, H-2), 3.44 (2H, t, J = 6.6 Hz, BnOCH2), 3.43-3.47 (1H, m, BnOCH2CH2CH2CH2CHaHb),
3.57 (1H, ddd, J = 2.3 Hz, J = 4.6 Hz, J = 9.3 Hz, H-5), 3.60 (1H, t, J = 8.8 Hz, H-4), 3.70 (1H, dd, J =
4.5 Hz, J = 10.7 Hz, Ha-6), 3.75 (1H, dd, J = 2.4 Hz, J = 10.7 Hz, Hb-6), 3.86 (1H, dt, J = 6.4 Hz, J = 9.6
Hz, BnOCH2CH2CH2CH2CHaHb), 4.10 (1H, dd, J = 8.3 Hz, J = 9.6 Hz, H-3), 4.79 (1H, d, J = 7.7 Hz,
13
H-1), 5.53 (1H, d, J = 7.9 Hz, NH), 4.47–4.82 (8H, m, CH2Ph), 7.19–7.34 (20H, m, Ph); C NMR (150
MHz, CDCl3): δ 22.7 (BnOCH2CH2CH2), 23.5 (CH3), 29.3 (BnOCH2CH2), 29.5 (BnOCH2CH2CH2CH2),
57.1 (C-2), 69.1 (C-6), 69.4 (BnOCH2CH2CH2CH2CH2), 70.3 (BnOCH2), 72.9–74.6 (CH2Ph), 74.8 (C-5),
78.7 (C-4), 80.4 (C-3), 99.8 (C-1), 127.5–128.5 (Ph), 138.1–138.6 (Ph), 170.3 (C=O); HRMS (ESI): m/z
calcd for C41H49NO7Na+: 690.3401; found: 690.3389.
3-β-Cholestanyl 2-Acetamido-3,4,6-tri-O-benzyl-2-deoxy-D-glucopyranoside (21)
Using the same procedure as described above for 3, Yb(OTf)3 (129.0 mg, 0.2 mmol) was added to a
solution of 1 (133.2 mg, 0.2 mmol), 8 (80.8 mg, 0.1 mmol), and BF3·OEt2 (62 μL, 0.006 mmol) in
CH2Cl2 (3 mL) to give 21 (PTLC; EtOAc/hexane = 2/1, 70% yield, α form; 28.8 mg, β form; 96.4 mg, α/β
ratio = 23/77) as white crystals. α Form; Rf 0.28 (EtOAc/hexane = 2/1); mp 164.4–166.0 °C; [α]27D +82.6
1
(c 1.0, CHCl3); H NMR (600 MHz, CDCl3): δ 1.86 (3H, s, CH3), 0.57-1.97 (47H, m, 3-β-cholestanyl),
3.50 (1H, dt, J = 5.4 Hz, J= 10.9 Hz, CH), 3.68 (1H, t, J = 9.5 Hz, H-3), 3.67 (1H, dd, J = 1.9 Hz, J =
10.9 Hz, Ha-6), 3.72 (1H, t, J = 9.3 Hz, H-4), 3.76 (1H, dd, J = 4.3 Hz, J = 8.8 Hz, Hb-6), 3.89 (1H, ddd, J
= 1.9 Hz, J = 4.1 Hz, J = 9.4 Hz, H-5), 4.24 (1H, dt, J = 3.8 Hz, J = 9.8 Hz, H-2), 4.50–4.85 (6H, m,
CH2Ph), 4.91 (1H, d, J = 3.8 Hz, H-1), 5.32 (1H, d, J = 9.3 Hz, NH), 7.16–7.35 (15H, m, Ph); 13C NMR
(150 MHz, CDCl3): δ 23.5 (CH3), 12.1–56.4 (3-β-cholestanyl), 52.5 (C-2), 68.7 (C-6), 70.9 (C-5),
73.4–75.0 (CH2Ph), 77.0 (CH), 78.5 (C-4), 80.8 (C-3), 96.2 (C-1), 169.6 (C=O), 127.6–128.5 (Ph),
138.1-138.6 (Ph); HRMS (ESI): m/z calcd for C56H79NO6Na+: 884.5800; found: 884.5843. β Form; Rf
1
0.41 (EtOAc/hexane = 2/1); mp 164.0–165.3 °C; [α]26 +28.8 (c 1.0, CHCl3); H NMR (600 MHz,
D
CDCl3): δ 1.84 (3H, s, CH3), 0.63-1.97 (47H, m, 3-β-cholestanyl), 3.19 (1H, td, J = 7.9 Hz, J = 9.6 Hz,

H-2), 3.54–3.59 (3H, m, H-4, H-5, CH), 3.68 (1H, dd, J = 4.1 Hz, J = 10.7 Hz, Ha-6), 3.75 (1H, dd, J =
1.0 Hz, J = 10.7 Hz, Hb-6), 4.25 (1H, dd, J = 9.6 Hz, J = 8.3 Hz, H-3), 4.54–4.83 (6H, m, CH2Ph), 5.00
13
(1H, d, J = 7.9 Hz, H-1), 5.57 (1H, d, J = 7.2 Hz, NH), 7.20-7.34 (15H, m, Ph); C NMR (150 MHz,
CDCl3): δ 23.6 (CH3), 12.1–56.5 (3-β-cholestanyl), 58.2 (C-2), 69.2 (C-6), 73.4–74.7 (CH2Ph), 74.7 (C-5),
78.8 (C-4), 79.1 (CH), 80.4 (C-3), 98.1 (C-1), 127.5-128.4 (Ph), 138.1-138.6 (Ph), 170.3 (C=O); HRMS
(ESI): m/z calcd for C56H79NO6Na+: 884.5800; found: 884.5833.
Cyclohexyl 2-Acetamido-3,4,6-tri-O-benzyl-2-deoxy-D-glucopyranoside (22)27
Using the above same procedure as described above for 3, Yb(OTf)3 (130.0 mg, 0.2 mmol) was added to
a solution of 1 (134.2 mg, 0.2 mmol), 9 (21 mg, 0.3 mmol), and BF3·OEt2 (63 μL, 0.006 mmol) in CH2Cl2
(3 mL) to give 21 (PTLC; EtOAc/hexane = 2/1, 81.7 mg, 68% yield, α/β ratio = 53/47) as white crystals.
1
α And β27 from mixture; Rf 0.72 (EtOAc/hexane = 2/1); H NMR (600 MHz, CDCl3): δ 1.83 (3H, s,
α-CH3), 1.84 (3H, s, β-CH3), 1.17–1.93 (20H, m, cyclohexyl), 3.21 (1H, dt, J = 7.9 Hz, J = 9.8 Hz, β-H-2),
3.55–3.57 (3H, m, α-CH, β-H-5, β-H-4), 3.59–3.63 (2H, m, β-CH, α-H-3), 3.66–3.78 (5H, m, α-H-6,
β-H-6, α-H-4), 3.89 (1H, ddd, J = 1.7 Hz, J = 4.0 Hz, J = 9.6 Hz, α-H-5), 4.23–4.27 (2H, m,
α-H-2β-H-3), 4.50–4.86 (12H, m, CH2Ph), 4.92 (1H, d, J = 3.8 Hz, α-H-1), 5.00 (1H, d, J = 8.1 Hz,
13
β-H-1), 5.26 (1H, d, J = 9.3 Hz, α-NH), 5.69 (1H, d, J = 7.6 Hz, β-NH), 7.17–7.35 (30H, m, Ph); C
NMR (150 MHz, CDCl3): δ 23.4 (α-CH3), 23.6 (β-CH3), 23.4-25.6 (cyclohexyl), 52.6 (α-C-2), 58.2
(β-C-2), 68.7 (α-C-6), 69.2 (β-C-6), 71.0 (α-C-5), 73.4-74.8 (CH2Ph), 74.7 (β-C-5), 75.1 (α-CH), 77.3
(β-CH), 78.5 (α-C-4), 79.0 (β-C-4), 80.4 (β-C-3), 80.5 (α-C-3), 95.9 (α-C-1), 98.0 (β-C-1), 127.5-128.5
(Ph), 138.1-138.6 (Ph), 169.6 (α-C=O), 170.3 (β-C=O); HRMS (ESI): m/z calcd for C35H43NO6Na+:
596.2983; found: 596.2981.
2-Adamantyl 2-Acetamido-3,4,6-tri-O-benzyl-2-deoxy-D-glucopyranoside (23)
Using the same procedure as described above for 3, Yb(OTf)3 (144.2 mg, 0.2 mmol) was added to a
solution of 1 (148.9 mg, 0.3 mmol), 10 (35.4 mg, 0.2 mmol), and BF3·OEt2 (70 μL, 0.007 mmol) in
CH2Cl2 (3 mL) to give 23 (PTLC; EtOAc/hexane = 2/1, 71% yield, α form; 31.5 mg, β form; 71.4 mg, α/β
ratio = 31/69) as white crystals. α Form; Rf 0.63 (EtOAc/hexane = 2/1); mp 121.0–122.8 °C; [α]26D +82.6
1
(c 0.55, CHCl3); H NMR (600 MHz, CDCl3): δ 1.79 (3H, s, CH3), 1.50–2.17 (14H, m, 2-adamantyl),
3.67 (1H, dd, J = 1.6 Hz, J = 10.7 Hz, Ha-6), 3.72-3.80 (4H, m, H-3, H-4, Hb-6, CH), 3.88 (1H, bd, J =
9.8 Hz, H-5), 4.20 (1H, dt, J = 3.5 Hz, J = 9.7 Hz, H-2), 4.50–4.87 (6H, m, CH2Ph), 4.94 (1H, d, J = 3.6
13
Hz, H-1), 5.12 (1H, d, J = 9.1 Hz, NH), 7.20–7.36 (15H, m, Ph); C NMR (150 MHz, CDCl3): δ 23.4
(CH3), 27.1–37.4 (2-adamantyl), 52.7 (C-2), 68.7 (C-6), 71.3 (C-5), 73.4–75.2 (CH2Ph), 78.5 (C-4), 79.5
(CH), 79.8 (C-3), 95.8 (C-1), 127.6-128.5 (Ph), 138.0-138.7 (Ph), 169.5 (C=O); HRMS (ESI): m/z calcd

for C39H47NO6Na+: 648.3296; found: 648.3252. β Form; Rf 0.78 (EtOAc/hexane = 2/1); mp 119.8–
121.8 °C; [α]26D +19.4 (c 1.1, CHCl3); 1H NMR (600 MHz, CDCl3): δ 1.83 (3H, s, CH3), 1.44–2.17 (14H,
m, 2-adamantyl), 3.36 (1H, dt, J = 8.4 Hz, J= 9.7 Hz, H-2), 3.60 (1H, t, J = 8.8 Hz, H-4), 3.68 (1H, dd, J
= 4.6 Hz, J = 10.7 Hz, Ha-6), 3.76 (1H, dd, J = 1.9 Hz, J = 10.7 Hz, Hb-6), 3.87 (1H, s, CH), 3.88 (1H, m,
H-5), 4.19 (1H, t, J = 9.0 Hz, H-3), 4.55–4.84 (6H, m, CH2Ph), 4.92 (1H, d, J = 7.9 Hz, H-1), 5.56 (1H, d,
J = 7.6 Hz, NH), 7.21–7.35 (15H, m, Ph); 13C NMR (150 MHz, CDCl3): δ 23.6 (CH3), 27.1–37.6
(2-adamantyl), 57.8 (C-2), 69.1 (C-6), 73.4–74.6 (CH2Ph), 74.8 (C-5), 79.0 (C-4), 80.4 (C-3), 80.7 (CH),
97.7 (C-1), 127.5-128.5 (Ph), 138.2-138.7 (Ph), 170.2 (C=O); HRMS (ESI): m/z calcd for C39H47NO6Na+:
648.3296; found: 648.3255.
Methyl 6-O-(2’-Acetamido-3’,4’,6’-tri-O-benzyl-2’-deoxy-D-glucopyranosyl)-2,3,4-tri-O-benzyl-α-
D-glucopyranoside (24)24
Using the same procedure as described above for 3, Yb(OTf)3 (128.2 mg, 0.2 mmol) was added to a
solution of 1 (132.4 mg, 0.2 mmol), 11 (96.0 mg, 0.2 mmol), and BF3·OEt2 (62 μL, 0.006 mmol) in
CH2Cl2 (3 mL) to give 24 (PTLC; EtOAc/hexane = 2/1, 37% yield, α form; 24.9 mg, β form24; 45.7 mg,
α/β ratio = 35/65) as white crystals. α Form; Rf 0.23 (EtOAc/hexane = 2/1); mp 164.0–165.6 °C; [α]26
D
+86.6 (c 1.1, CHCl3); 1H NMR (600 MHz, CDCl3): δ 1.70 (3H, s, CH3), 3.33 (3H, s, OCH3), 3.37 (1H, t,
J = 9.5 Hz, H-4’), 3.42 (1H, dd, J = 3.6 Hz, J = 9.6 Hz, H-3), 3.56-3.59 (2H, m, Ha-6’ Ha-6), 3.61 (1H, dd,
J = 8.3 Hz, J = 10.4 Hz, H-3’), 3.67 (1H, dd, J = 3.4 Hz, J = 10.7 Hz, Hb-6’), 3.69–3.74 (3H, m, H-5,
H-5’, H-4’), 3.85 (1H, dd, J = 4.6 Hz, J = 11.3 Hz, Hb-6), 3.98 (1H, t, J = 9.2 Hz, H-2), 4.19 (1H, dt, J =
3.6 Hz, J = 9.9 Hz, H-2’), 4.45–5.02 (12H, m, CH2Ph), 4.52 (1H, d, J = 2.9 Hz, H-1), 4.80 (1H, d, J = 4.1
13
Hz, H-1’), 5.20 (1H, d, J = 9.3 Hz, NH), 7.17–7.37 (30H, m, Ph); C NMR (150 MHz, CDCl3): δ 23.4
(CH3), 52.6 (C-2’), 55.2 (OCH3), 66.7 (C-6), 68.4 (C-6’), 69.7 (C-5’), 71.3 (C-5), 72.9–74.6 (CH2Ph),
77.7 (C-4), 78.3 (C-4’), 79.7 (C-3’), 80.0 (C-3), 82.0 (C-2), 97.9 (C-1), 98.5 (C-1’), 127.5–128.5 (Ph),
138.1–138.6 (Ph), 169.5 (C=O); HRMS (ESI): m/z calcd for C57H63NO11Na+: 960.4293; found: 960.4283.
1
β Form; Rf 0.65 (EtOAc/hexane = 2/1); mp 194.5–195.8 °C; [α]26 +25.9 (c 2.1, CHCl3); H NMR (600
D
MHz, CDCl3): δ 1.70 (3H, s, CH3), 3.34 (3H, s, OCH3), 3.49–3.51 (1H, m, H-3’), 3.52 (1H, t, J = 8.9 Hz,
H-4), 3.59 (2H, m, H-4’, H-5’), 3.68 (1H, dd, J = 3.6 Hz, J = 11.2 Hz, Ha-6), 3.70-3.74 (3H, m, H-5’,
H-6’), 3.97 (1H, t, J = 9.3 Hz, H-2), 4.09 (1H, t, J = 9.2 Hz, H-3), 4.09–4.11 (1H, m, Hb-6), 4.49–4.98
(12H, m, CH2Ph), 4.58 (1H, d, J = 3.3 Hz, H-1), 4.83 (1H, d, J = 7.2 Hz, H-1’), 5.44 (1H, d, J = 7.7 Hz,
13
NH), 7.19–7.34 (30H, m, Ph); C NMR (150 MHz, CDCl3): δ 23.5 (CH3), 52.1 (OCH3), 56.7 (C-2’),
67.4 (C-6), 69.1 (C-6’), 69.6 (C-5’), 73.3-75.7 (CH2Ph), 74.9 (C-5), 77.6 (C-4), 78.6 (C-4’), 79.7 (C-3’),
80.1 (C-3), 82.0 (C-2), 98.0 (C-1), 99.8 (C-1’), 127.5–128.4 (Ph), 138.0–138.8 (Ph), 170.1 (C=O); HRMS
(ESI): m/z calcd for C57H63NO11Na+: 960.4293; found: 961.4316.

Phenyl 2-Acetamido-3,4,6-tri-O-benzyl-2-deoxy-α-D-glucopyranoside (25)
Using the same procedure as described above for 3, Yb(OTf)3 (124 mg, 0.2 mmol) was added to a
solution of 1 (141 mg, 0.3 mmol), 12 (20.6 mg, 0.2 mmol), and BF3·OEt2 (66 μL, 0.007 mmol) in CH2Cl2
(3 mL) to give 25 (PTLC; EtOAc/hexane = 2/1, 83.4 mg, 67% yield) as white crystals. Rf 0.47
(EtOAc/hexane = 2/1); mp 161.1–161.8 °C; [α]28D +148.8 (c 1.0, CHCl3); 1H NMR (600 MHz, CDCl3): δ
1.75 (3H, s, CH3), 3.44 (1H, dt, J = 3.4 Hz, J = 9.6 Hz, H-2), 3.54 (1H, d, J = 11.0 Hz, H a-6), 3.68 (1H,
dd, J = 2.1 Hz, J = 11.0 Hz, H b-6), 3.78-3.90 (3H, m, H-3, H-4, H-5), 4.37-4.85 (6H, m, CH2Ph), 5.28
13
(1H, d, J = 8.9 Hz, NH), 5.47 (1H, d, J = 4.1 Hz, H-1), 6.80–7.40 (20H, m, Ph); C NMR (150 MHz,
CDCl3): δ 23.3 (CH3), 52.5 (C-2), 68.3 (C-6), 71.6 (C-5), 73.4–75.1 (CH2Ph), 78.2 (C-4), 79.8 (C-3), 96.3
(C-1), 116.6 (Ph), 122.6 (Ph), 129.6 (Ph), 156.1 (Ph), 169.9 (C=O), 127.6–128.5 (Ph), 137.9–138.4 (Ph);
HRMS (ESI): m/z calcd for C35H37NO6Na+: 590.2513; found: 590.2514.
4-O-Methylphenyl 2-Acetamido-3,4,6-tri-O-benzyl-2-deoxy-α-D-glucopyranoside (26)
Using the same procedure as described above for 3, Yb(OTf)3 (124.2 mg, 0.2 mmol) was added to a
solution of 1 (128.0 mg, 0.2 mmol), 13 (25 mg, 0.2 mmol), and BF3·OEt2 (60 μL, 0.006 mmol) in CH2Cl2
(3 mL) to give 26 (PTLC; EtOAc/hexane = 2/1, 100.6 mg, 84% yield) as white crystals. Rf 0.58
(EtOAc/hexane = 2/1); mp 189.2–189.8 °C; [α]25D +172.1 (c 1.0, CHCl3); 1H NMR (600 MHz, CDCl3): δ
1.77 (3H, s, CH3), 3.56 (1H, dd, J = 2.1 Hz, J = 11.0 Hz, Ha-6), 3.68 (1H, s, PhCH3), 3.69 (1H, bd, J =
11.0 Hz, Hb-6), 3.78 (1H, t, J = 8.9 Hz, H-4), 3.82 (1H, t, J = 9.3 Hz, H-3), 3.87 (1H, ddd, J = 9.6 Hz, J =
3.4 Hz, J = 1.4 Hz, H-5), 4.32 (1H, dt, J = 3.4 Hz, J = 9.6 Hz, H-2), 4.38–4.84 (6H, m, CH2Ph), 5.28 (1H,
d, J = 8.9 Hz, NH), 5.35 (1H, d, J = 3.4 Hz, H-1), 6.72 (2H, d, J = 8.9 Hz, Ph), 6.87 (2H, d, J = 8.9 Hz,
Ph), 7.17–7.31 (15H, m, Ph); 13C NMR (150 MHz, CDCl3): δ 23.4 (CH3), 52.6 (C-2), 55.6 (PhCH3), 68.4
(C-6), 71.5 (C-5), 73.4–75.1 (CH2Ph), 78.3 (C-4), 79.9 (C-3), 97.2 (C-1), 114.6 (Ph), 118.0 (Ph),
128.5–127.6 (Ph), 150.1 (Ph), 155.2 (Ph), 169.8 (C=O), 138.0-138.4 (Ph); HRMS (ESI): m/z calcd for
C36H39NO7Na+: 620.2619; found: 620.2616.
4-Benzoyloxyphenyl 2-Acetamido-3,4,6-tri-O-benzyl-2-deoxy-α-D-glucopyranoside (27)
Using the same procedure as described above for 3, Yb(OTf)3 (113.8 mg, 0.2 mmol) was added to a
solution of 1 (117.5 mg, 0.2 mmol), 14 (39.3 mg, 0.2 mmol), and BF3·OEt2 (55 μL, 0.006 mmol) in
CH2Cl2 (3 mL) to give 27 (PTLC; EtOAc/hexane = 2/1, 70.2 mg, 57% yield) as white crystals. Rf 0.81
(EtOAc/hexane = 2/1); mp 190.5–191.7 °C; [α]27D +160.8 (c 1.0, CHCl3); 1H NMR (600 MHz, CDCl3): δ
1.84 (3H, s, CH3), 3.64 (1H, d, J = 10.8 Hz, Ha-6), 3.78 (1H, dd, J = 1.5 Hz, J = 11.0 Hz, Hb-6),
3.90–3.92 (3H, m, H-3, H-4, H-5), 4.42 (1H, ddd, J = 3.3 Hz, J = 6.7 Hz, J = 12.5 Hz, H-2), 4.46–4.93
(6H, m, CH2Ph), 5.30 (1H, d, J = 9.1 Hz, NH), 5.54 (1H, d, J = 3.4 Hz, H-1), 7.07 (2H, d, J = 9.1 Hz, Ph),

7.12 (2H, d, J = 9.1 Hz, Ph), 7.20–7.40 (15H, m, Ph), 7.51 (2H, t, J = 7.8 Hz, Ph), 7.63 (1H, dt, J = 1.3 Hz,
13
J = 7.5 Hz, Ph), 8.19 (2H, dd, J = 1.3 Hz, J = 8.3 Hz, Ph); C NMR (150 MHz, CDCl3): δ 23.4 (CH3),
52.5 (C-2), 68.2 (C-6), 71.8 (C-5), 73.5-75.1 (CH2Ph), 78.2 (C-4), 79.8 (C-3), 96.8 (C-1), 117.4 (Ph),
122.7 (Ph), 127.7-128.6 (Ph), 129.5 (Ph), 130.1-130.2 (Ph), 133.6 (Ph), 137.9–138.4 (Ph), 145.9 (Ph),
153.9 (Ph), 165.4 (C=O), 169.9 (C=O(CH3)); HRMS (ESI): m/z calcd for C42H39NO8Na+: 710.2724;
found: 710.2734.
4-O-(2-Acetamido-3,4,6-tri-O-benzyl-2-deoxy-α-D-glucopyranosyl)-benzoic acid benzyl ester (28)
Using the same procedure as described above for 3, Yb(OTf)3 (80.0 mg, 0.13 mmol) was added to a
solution of 1 (82.6 mg, 0.15 mmol), 15 (29.4 mg, 0.13 mmol), and BF3·OEt2 (39 μL, 0.004 mmol) in
CH2Cl2 (3 mL) to give 28 (PTLC; EtOAc/hexane = 2/1, 19.2 mg, 46% yield) as white crystals. Rf 0.57
(EtOAc/hexane = 2/1); mp 147.2–148.1 °C; [α]25D +163.7 (c 1.0, CHCl3); 1H NMR (600 MHz, CDCl3): δ
1.74 (3H, s, CH3), 3.49 (1H, d, J = 9.8 Hz, H a-6), 3.66 (1H, dd, J = 3.5 Hz, J = 10.9 Hz, H b-6 ), 3.71 (1H,
d, J = 8.1 Hz, H-5), 3.82 (2H, m, H-3, H-4), 4.33 (1H, dd, J = 6.7 Hz, J = 8.9 Hz, H-2), 4.35–4.85 (6H, m,
CH2Ph), 5.15 (1H, d, J = 8.8 Hz, NH), 5.25 (2H, d, J = 2.6 Hz, CH2Ph), 5.56 (1H, d, J = 3.3 Hz, H-1),
6.97 (2H, d, J = 8.8 Hz, Ph), 7.10–7.35 (20H, m, Ph), 7.93 (2H, d, J = 8.6 Hz, Ph); 13C NMR (150 MHz,
CDCl3): δ 23.2 (CH3), 52.4 (C-2), 66.5 (CH2Ph), 68.1 (C-6), 71.8 (C-5), 73.4–75.1 (CH2Ph ), 78.0 (C-4),
79.4 (C-3), 95.9 (C-1), 116.0 (Ph), 124.3 (Ph), 131.7 (Ph), 136.1 (Ph), 159.7 (Ph), 165.8 (C=O), 170.0
(C=O(CH3)), 127.7-128.6 (Ph), 137.7-138.2 (Ph); HRMS (ESI): m/z calcd for C43H43NO8Na+: 724.2881;
found: 724.2883.
4-O-(2-Acetamido-3,4,6-tri-O-benzyl-2-deoxy-α-D-glucopyranosyl)-N-benzyloxycarbonyl-L-tyrosine
benzyl ester (29)
Using the same procedure as described above for 3, Yb(OTf)3 (76.0 mg, 0.1 mmol) was added to a
solution of 1 (78.4 mg, 0.1 mmol), 16 (49.7 mg, 0.1 mmol), and BF3·OEt2 (37 μL, 0.004 mmol) in
CH2Cl2 (3 mL) to give 29 (PTLC; EtOAc/hexane = 2/1, 64.8 mg, 60% yield) as white crystals. Rf 0.70
(EtOAc/hexane = 2/1); mp 169.9–170.1 °C; [α]25D +105.5 (c 1.1, CHCl3); 1H NMR (600 MHz, CDCl3): δ
1.74 (3H, s, CH3), 2.96 (2H, m, PhCH2CH), 3.50 (1H, d, J = 9.8 Hz, Ha-6), 3.67 (1H, dd, J = 3.2 Hz, J =
10.9 Hz, Hb-6), 3.76 (1H, bd, J = 6.9 Hz, H-5), 3.81–3.82 (2H, m, H-3, H-4), 4.33 (1H, td, J = 4.0 Hz, J =
9.3 Hz, H-2), 4.35–4.84 (6H, m, CH2Ph), 4.57 (1H, dd, J = 5.5 Hz, J = 13.2 Hz, CH), 5.00 (2H, s,
NHC(O)OCH2Ph), 5.02 (1H, d, J = 12.5 Hz, C(O)OCHaHbPh), 5.07 (1H, d, J = 12.0 Hz,
C(O)OCHaHbPh), 5.16 (1H, d, J = 8.1 Hz, NH), 5.22 (1H, d, J = 9.1 Hz, NH), 5.41 (1H, d, J = 3.4 Hz,
H-1), 6.76 (1H, d, J = 8.3 Hz, Ph), 6.80 (1H, d, J = 8.4 Hz, Ph), 7.10–7.31 (25H, m, Ph); 13C NMR (150
MHz, CDCl3): δ 23.3 (CH3), 37.2 (PhCH2CH), 52.3 (C-2), 54.8 (CH), 66.9 (NHC(O)OCH2Ph), 67.2

(C(O)OCH2Ph), 68.1 (C-6), 71.6 (C-5), 73.3–75.0 (CH2Ph), 78.0 (C-4), 79.7 (C-3), 96.2 (C-1), 116.5 (Ph),
127.6-128.6 (Ph), 129.6 (Ph), 130.4 (Ph), 135.0-136.1 (Ph), 137.8–138.3 (Ph), 155.1 (Ph), 155.5 (Ph),
169.8 (C=O(CH3)), 172.2 (C=O); HRMS (ESI): m/z calcd for C53H54NO10Na+: 901.3671; found:
901.3675.
4-Hydroxyphenyl
2-acetamido-3,4,6-tri-O-benzyl-2-deoxy-α-D-glucopyranoside
(35)
and
4-tert-butoxyphenyl 2-acetamido-3,4,6-tri-O-benzyl-2-deoxy-α-D-glucopyranoside (36)
Yb(OTf)3 (126.9 mg, 0.20 mmol) was added to a solution of 1 (133.8 mg, 0.25 mmol), 34 (35.0 mg, 0.21
mmol), and BF3·OEt2 (0.8 μL, 0.006 mmol) in CH2Cl2 (2 mL) at 0 °C. The resulting mixture was stirred
for 1 h at room temperature and then quenched by the addition of sat. aq. NaHCO3 solution (5 mL). The
reaction mixture was then extracted with CH2Cl2, and the organic layer was rinsed with water and sat. aq.
NaCl solution. After the organic layer was dried over Na2SO4, the solvent was evaporated under reduced
pressure. The crude products were purified via preparative silica gel TLC (EtOAc/hexane = 1/1) to give
35 (80.3 mg, 66%) and 36 (10.7 mg, 8%) as white crystals. Compound 35; Rf 0.12 (EtOAc/hexane = 1/1);
1
mp 207.2–209.2 °C; [α]23 +38 (c 0.9, CHCl3); H NMR (600 MHz, CDCl3): 1.81 (3H, s, CH3), 3.63
D
(1H, d, J = 10.7 Hz, Ha-6), 3.76 (1H, dd, J = 3.9 Hz, J = 9.5 Hz, Hb-6), 3.84–3.94 (3H, m, H-3, H-4, H-5),
4.33 (1H, dt, J = 3.9 Hz, J = 9.5 Hz, H-2), 4.44 (1H, d, J = 12.2 Hz, CH2Ph), 4.57 (1H, d, J = 10.7 Hz,
CH2Ph), 4.60 (1H, d, J = 12.2 Hz, CH2Ph), 4.68 (1H, d, J = 11.7 Hz, CH2Ph), 4.83 (1H, d, J = 10.7 Hz,
CH2Ph), 4.90 (1H, d, J = 11.7 Hz, CH2Ph), 5.30 (1H, d, J = 8.5 Hz, NH), 5.40 (1H, d, J = 3.7 Hz, H-1),
6.68 (2H, d, J = 9.1 Hz, Ph), 6.82 (2H, d, J = 8.8 Hz, Ph), 7.20–7.37 (15H, m, Ph); 13C-NMR (150 MHz,
CDCl3) 23.4 (CH3), 52.8 (C-2), 68.3 (C-6), 71.5 (C-5), 73.4 (CH2Ph), 74.9 (CH2Ph), 75.1 (CH2Ph),
78.3 (C-4), 79.6 (C-3), 97.1 (C-1), 116.1 (Ph), 118.1 (Ph), 127.6-151.5 (Ph), 170.2 (C=O); Anal. Calcd
for C35H37NO7: C, 72.02; H, 6.39; N, 2.40. Found: C, 71.80; H, 6.40; N, 2.36. Compound 36; Rf 0.36
1
(EtOAc/hexane = 1/1); mp 135.2–137.2 °C; [α]23 +134 (c 0.3, CHCl3); H NMR (600 MHz, CDCl3): δ
D
1.29 (9H, s, CH3), 1.83 (3H, s, CH3), 3.63 (1H, dd, J = 1.7 Hz, J = 11.0 Hz, Ha-6), 3.76 (1H, dd, J = 3.4
Hz, J = 11.0 Hz, Hb-6), 3.86-3–89 (2H, m, H-3, H-4), 3.91-3.93 (1H, m, H-5), 4.38 (1H, dt, J = 3.7 Hz, J
= 9.5 Hz, H-2), 4.46 (1H, d, J = 12.2 Hz, CH2Ph), 4.56 (1H, d, J = 10.8 Hz, CH2Ph), 4.62 (1H, d, J = 11.9
Hz, CH2Ph), 4.70 (1H, d, J = 11.7 Hz, CH2Ph), 4.83 (1H, d, J = 10.8 Hz, CH2Ph), 4.90 (1H, d, J = 11.7
Hz, CH2Ph), 5.28 (1H, d, J = 9.0 Hz, NH), 5.44 (1H, d, J = 3.5 Hz, H-1), 6.89 (4H, m, Ph), 7.18–7.39
13
(15H, m, Ph); C NMR (150 MHz, CDCl3): δ 23.4 (Ac), 28.7 (Me x 3), 52.4 (C-2), 68.3 (C-6), 71.6
(C-5), 73.4 (CH2Ph), 74.8 (CH2Ph), 75.1 (CH2Ph), 78.2 (C-4), 78.4 (C), 79.8 (C-3), 97.0 (C-1), 117.1
(Ph), 125.4 (Ph), 127.7–128.6 (Ph), 137.8 (Ph), 137.9 (Ph), 138.3 (Ph), 150.4 (Ph), 152.2 (Ph), 169.8
(C=O); Anal. Calcd for C39H45NO7·2.5H2O: C, 68.40; H, 7.36; N, 2.05. Found: C, 68.69; H, 7.09; N,
1.99.

4-Hydroxyphenyl 2-acetamido-2-deoxy-α-D-glucopyranoside (31)
Palladium hydroxide (26.4 mg, 0.1 mmol) was added to a solution of 35 (54.6 mg, 0.1 mmol) in
THF/MeOH (5 mL/5 mL). Hydrogen was then bubbled through the solution for 1 h. After the solvent was
filtered and evaporated under reduced pressure, the crude product was purified via flash column
chromatography on silica gel (CHCl3/MeOH = 8/1) to afford 31 (27.3 mg, 93%) as white crystals. Rf 0.10
1
(CHCl3/MeOH = 8/1); mp 78.8–80.8 °C; [α]23 +150 (c 1.1, MeOH); H NMR (600 MHz, D2O) 1.91
D
(3H, s, CH3), 3.44 (1H, t, J = 9.6 Hz, H-4), 3.65–3.67 (2H, m, H-6), 3.69–3.71 (1H, m, H-5), 3.80 (1H, t,
J = 10.3 Hz, H-3), 3.91 (1H, dd, J = 3.4 Hz, J = 11.0 Hz, H-2), 5.27 (1H, d, J = 2.7 Hz, H-1), 6.70 (2H, d,
J = 9.0 Hz, Ph), 6.87 (2H, d, J = 9.0 Hz, Ph); 13C NMR (150 MHz, D2O) 22.6 (CH3), 54.3 (C-2), 61.0
(C-6), 70.5 (C-4), 71.6 (C-3), 73.2 (C-5), 97.7 (C-1), 116.8 (Ph), 119.5 (Ph), 150.3 (Ph), 151.9 (Ph), 175.0
(C=O); Anal. Calcd for C14H19NO7: C, 53.67; H, 6.11; N, 4.47. Found: C, 53.45; H, 6.44; N, 4.23.
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