N-Heterocyclic Carbene Catalyzed Stereoselective Synthesis of 2-Nitro-thiogalactosides

Article abstract of DOI:10.1055/s-0039-1690099

A highly selective NHC-catalyzed Michael addition of alkanethiols or thiophenol to 2-nitro- d -galactal compounds for the synthesis of 2-nitro-thiogalactoside derivatives has been developed for the first time. A wide variety of 1,2- cis -2-nitro-thiogalactosides can be prepared in good to excellent yields and high to excellent α-selectivities.

Full text of DOI:10.1055/s-0039-1690099

SYNTHESIS
0
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8
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1
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7
-
2
1
0
X
© Georg Thieme Verlag Stuttgart · New York
2019, 51, A–K
paper
A
en
Y.-L. Hu et al.
Paper
Synthesis
N-Heterocyclic Carbene Catalyzed Stereoselective Synthesis of
2-Nitro-thiogalactosides
Yu-Long Hu ‡
Cl
Bo-Bo Gou ‡
Jiao Wang
Ming Zhao
Jia-Lin Liu
Jie Chen*
N
N
Mes
(0.15 equiv)
O
O
SR
Mes
PO
BnO
PO
BnO
RSH
+
NO2
Cs2CO3 (0.1 equiv)
DCM, r.t., 24 h
NO2
OBn
OBn
R = alkyl, α:β = 4:1 to 1:0
R = aryl, α:β > 25:1
27 examples
up to 95%
yield
Ling Zhou*
Key Laboratory of Synthetic and Natural Functional Molecule
Chemistry of Ministry of Education, Department of Chemistry &
Materials Science, National Demonstration Center for Experi-
mental Chemistry Education, Northwest University, Xi’an
710127, P. R. of China
chmchenj@nwu.edu.cn
zhoul@nwu.edu.cn
‡ These authors contributed equally to this work.
Received: 18.02.2019
Accepted after revision: 21.05.2019
Published online: 26.06.2019
kyl halides provides the opportunity to construct thioglyco-
sides in a stereoselective manner, the efficient synthesis of
glycosyl thiols is not easy.7 Therefore, the development of
efficient and diastereoselective synthetic methods to syn-
thesize thioglycosides using simple starting materials is
highly desirable.
DOI: 10.1055/s-0039-1690099; Art ID: ss-2019-h0107-op
Abstract A highly selective NHC-catalyzed Michael addition of alkan-
ethiols or thiophenol to 2-nitro-D-galactal compounds for the synthesis
of 2-nitro-thiogalactoside derivatives has been developed for the first
time. A wide variety of 1,2-cis-2-nitro-thiogalactosides can be prepared
in good to excellent yields and high to excellent -selectivities.
Scheme 1 outlines current procedures for the construc-
tion of 2-amino-2-deoxy thioglycoside bonds from thiols.
For example, -selective thioglycoside bond formation can
be achieved by SN2 reaction of halogenoses under basic con-
ditions,8 because the halogen atom generally adopts the ax-
ial position. Similar results could also be obtained under
Lewis acid conditions.9 Very recently, Borbás and co-work-
ers developed a photoinitiated thiol-ene coupling reaction
of 2-substituted glycals with thiols to give 1,2-cis--thio-
glycosides at –80 °C.10 Notably, 2-nitroglycals are efficient
glycosyl donors for the formation of glycosidic bonds, offer-
ing excellent yields and high stereoselectivities.11 Indeed,
reaction of 2-nitrogalactal with thiophenol in the presence
of a stoichiometric amount of TlOEt gave the desired -
thioglycoside as the major products.12 Schmidt and co-
workers developed tBuOK-catalyzed thioglycosylation of 2-
nitrogalactals with thiophenol to construct S-glycosidic
bonds with excellent -selectivity.13 Recently, they explored
the same reaction with excellent -selectivity by using TEA
as the catalyst and controlling the reaction times.14 Sun, Yu,
and co-workers developed DMAP-catalyzed glycosylation of
2-nitrogalactals with thiophenol to give -thiogalactopyra-
noside as the major product.15 However, all these reactions
were performed by using thiophenols; reaction of 2-nitro-
galactals with thiols to give (alkylthio)glycosides has re-
mained unknown.
Key words N-heterocyclic carbenes, thiols, glycosylation, diastereose-
lectivity, catalysis
2-Amino-2-deoxyglycosides are ubiquitously distribut-
ed in organisms, such as the cells of glycolipid, lipopolysac-
charide, glycoprotein, heparin, hyaluronic acid, heparan
sulfate, chondroitin sulfate, and numerous aminoglycosidic
antibiotics.1 Many of these play vital roles in biochemistry
and biology.1,2 Besides O-glycosides, thioglycosides make up
the most abundant family of naturally occurring thiosug-
ars.3 Thioglycosides are widely used as protecting groups in
oligosaccharide synthesis, and the thio function can be acti-
vated by using a series of electrophiles to generate glyco-
sylating species.3,4 Moreover, it is already acknowledged
that S-glycosides are more stable than O-glycosides in the
chemical and enzymatic milieu.5 Consequently, the design
and synthesis of specific thioglycosides for potential use as
carbohydrate therapeutics has attracted considerable at-
tention. Many remarkable endeavors have been made to de-
velop the thioglycosylation method over the past de-
cades.4,6–10 However, compared with the well-documented
methodologies for the construction of O-glycosides, -se-
lective construction of thioglycosides has met with limited
success. Although direct reaction of glycosyl thiols with al-
© 2019. Thieme. All rights reserved. — Synthesis 2019, 51, A–K
Georg Thieme Verlag KG, Rüdigerstraße 14, 70469 Stuttgart, Germany

B
Y.-L. Hu et al.
Paper
Synthesis
Previous work:
bulky 2,4,6-trimethylphenyl substituents was used (entry
5). These results suggest that steric bulk in the aromatic
substituent of the NHC plays a crucial role in determining
glycosylation stereoselectivity (entry 5 vs entries 6 and 7).
O
X
O
SR
RO
RO
RO
conditions
PhSH
+
RO
NR1R2
NR1R2
OR
O
OR
X = F, Br: base, β selectivity
X = OAc,O(C=NH)CCl3: Lewis acid, β selectivity
O
SR
Table 1 Optimization of the Reaction Conditionsa
AcO
AcO
DPAP, hν
PhSH
PhSH
+
α selectivity
AcO
NHAc
AcO
NHAc
O
O
SEt
OAc
O
OAc
O
EtSH (2 equiv)
conditions
BnO
BnO
BnO
BnO
SPh
NO2
NO2
NO2
RO
RO
RO
RO
catalyst
OBn
OBn
+
1a
3a
NO2
OR
OR
O
N
N
PhSH, TlOEt (1 equiv), β selectivity
O
N
PhSH, tBuOK, β selectivity (major)
PhSH, TEA, α selectivity (major)
PhSH, DMAP, β selectivity
Mes
N
Cl
Previous work:
ClO4
N
N
Cl
Mes
N
S
Mes
Bn
This work: alkanethiols and PhSH, NHC, α selectivity (major)
4a
4b
4c
Cl
R
Scheme 1 2-Amino-2-deoxythioglycoside bond formation
Bn
N
N
R
N
Br
4e, R = Mes
4f, R = 4-FC6H4
4g, R = 2,6-iPr2C6H3
S
In the past decades, N-heterocyclic carbene (NHC) cata-
lyzed reactions have emerged as one of the most powerful
strategies to construct complex molecules.16 Recently, we
have developed several unconventional NHC-catalyzed re-
actions.17 Among them, NHC-catalyzed glycosylation of 2-
nitrogalactals with alcohols and phenol has been devel-
oped, and a variety of 1,2-cis-2-nitroglycosides can be pre-
pared in good to excellent yields and high to excellent -se-
lectivities.18 To continue our research interest in the devel-
opment and application of NHC-catalyzed reactions and C–
S bond construction,17–19 and to develop a new strategy for
the selective construction of S-glycosides, herein, we report
an efficient and stereoselective NHC-catalyzed Michael ad-
dition of thiols and thiophenol to 2-nitrogalactals to give -
thiogalactopyranosides as the major products.
Inspired by Schmidt’s thioglycosylation reactions and
the hydrogen-bonding activation model of NHC with the
sulfhydryl group,20 we hypothesized that such a bulky
NHC–thiol complex would be well suited as a mild promot-
er for the stereoselective glycosylation of 2-nitroglycals. To
test this hypothesis, 2-nitrogalactal (1a) and ethanethiol
(2a) were selected as model substrates. As shown in Table 1,
after treatment of 2-nitrogalactal and ethanethiol in a ratio
of 1:2 in the presence of triazolium salt 4a and cesium car-
bonate in dichloromethane at room temperature for 72
hours, the desired thiogalactopyranoside 3a was obtained
in 55% yield, albeit as a 2:1 / anomeric mixture (entry 1).
Then various NHC catalysts were screened; the chiral tri-
azolium salt 4b returned product 3a in 79% yield and as a
5:1 / anomeric mixture after 72 hours (entry 2). Thiazoli-
um salt 4c gave a further increase in -selectivity (entry 3).
The benzothiazole salt 4d resulted in 80% yield with moder-
ate stereoselectivity (entry 4). To our delight, when imidaz-
olium salts 4e–g were utilized as catalysts, the yields were
all improved (entries 5–7). More importantly, a 13:1 / ra-
tio was obtained when the imidazolium salt 4e with two
4d
Entry
Catalyst
Solvent
Time (h)
Yield (%)b
Ratio
/c
1
4a
4b
4c
4d
4e
4f
DCM
DCM
DCM
DCM
DCM
DCM
DCM
DCM
DCM
DCM
n-hexane
CCl4
72
72
48
24
24
24
24
48
36
48
48
48
72
72
8
55
2:1
5:1
7:1
5:1
13:1
6:1
5:1
3:1
6:1
9:1
6:1
7:1
3:1
–
2
79
3
60
4
80
5
85
6
87
7
4g
4e
4e
4e
4e
4e
4e
4e
4e
4e
4e
–
82
8d
9e
10f
11
12
13
14
15g
16h
17i
18j
19
71
75
80
77
80
MeCN
72
1,4-dioxane
DCM
trace
81
8:1
12:1
–
DCM
72
72
0.5
0.5
60
DCM
trace
75
DCM
2:1
3:1
–
DCM
80
a Reaction conditions: 1a (0.10 mmol), EtSH (0.20 mmol), catalyst 4 (0.015
mmol, 15 mol%), Cs2CO3 (0.010 mmol, 10 mol%), solvent (1.0 mL), r.t., un-
der argon.
b Yields of isolated products.
c Determined by 1H NMR spectroscopy.
d K2CO3 as base.
e KHMDS as base.
f tBuOK as base.
g At 40 °C.
h At 0 °C.
i At –30 °C.
j TEA as base.
© 2019. Thieme. All rights reserved. — Synthesis 2019, 51, A–K

C
Y.-L. Hu et al.
Paper
Synthesis
Then various bases were evaluated; K2CO3, KHMDS, and
tBuOK all provided diminished yields with decreased stere-
oselectivities (Table 1, entries 8–10). It seems that the bulky
cesium ion may also impact the selectivity. Next, we decid-
ed to explore the solvent effects by using 4e as the model
catalyst. The reactions proceeded smoothly in nonpolar sol-
vents such as n-hexane or CCl4, giving the desired product
in 77–80% yield with clearly decreased / ratios (entry 5 vs
entries 11 and 12). Notably, a poorer stereoselectivity was
observed when the polar solvent acetonitrile was used (/
3:1, entry 13). However, no reaction was detected when the
polar solvent 1,4-dioxane was used (entry 14). Further opti-
mization of this reaction by varying the temperature al-
lowed us to explore the optimal conditions; higher and
lower reaction temperatures all returned lower stereoselec-
tivities (entries 15–17). In addition, when TEA or Cs2CO3
was used as base without NHC under the optimal condi-
tions, both returned the desired product quickly, albeit
with poor stereoselectivity (entries 18 and 19).
To test the stability of compound 3a and the equilibra-
tion between 3a and 3a, compound 3a was treated with
a series of reaction conditions. As shown in Table 2, after
treatment of 3a under the optimal conditions in the ab-
sence of EtSH for 1 hour, about 5% of starting material 1a
was observed (entry 1). Upon addition of EtSH, 3a was re-
tained (entry 2). These results indicate that this Michael ad-
dition reaction is reversible. Interestingly, 3a was observed
after 24 hours under the same reaction conditions or when
using more NHC catalyst (entries 3–5). Precatalyst 4e in the
absence of Cs2CO3 gave no reaction, while Cs2CO3 in the ab-
sence of 4e returned 3a as a major product after 24 hours
(entries 6–8); this suggests that the base plays a key role in
the reversible process.
oselectivities. Alkanethiols all gave good yields (73–90%)
and high to excellent -stereoselectivities (13:1 to only ;
3a–d, 3pa–pb, 3s). Various benzyl thiols were well tolerated
by this method, and the corresponding products were ob-
tained in excellent yields and -selectivities (3f–m). Allyl
thiol, furfuryl thiol, cyclopentanethiol, and cyclohexanethi-
ol all gave the corresponding thioglycosides in good yields
(68–85%) and high to excellent -stereoselectivities (11:1 to
only ; 3na–o, 3q–rb). Notably, the reaction of C-6 silyl-
protected galactal with some thiols afforded the desired
products with clearly improved / ratios (3bb, 3eb, 3nb,
3rb vs 3ba, 3ea, 3na, 3ra), probably for steric reasons. Apart
from the simple thiols described above, an L-cysteine deriv-
ative were also selected as substrates to test this method.
Satisfactorily, the desired 3t was obtained in moderate yield
(60%) with acceptable -selectivity (/ 4:1). To further
demonstrate the value of this method, weakly nucleophilic
O
SR
O
PO
BnO
PO
BnO
4e (0.15 equiv), Cs2CO3 (0.10 equiv)
NO2
NO2
RSH (2 equiv), DCM, r.t., 24 h
OBn
OBn
3
1
O
SEt
O
S
O
S
BnO
PO
BnO
BnO
BnO
BnO
NO2
NO2
NO2
OBn
OBn
OBn
3a, 85% (13:1)
3ba, P = Bn, 81% (20:1)
3bb, P = TIPS, 73% (1:0)
3c, 87% (16:1)
R
O
Snheptyl
NO2
O
S
Bn
O
S
BnO
BnO
PO
BnO
BnO
BnO
NO2
NO2
OBn
OBn
OBn
3d, 90% (20:1)
3ea, P = Bn, 75% (21:1)
3eb, P = TIPS, 75% (25:1)
3f, R = H, 84% (16:1)
3g, R = 4-Me, 92% (20:1)
3h, R = 4-tBu, 85% (15:1)
3i, R = 4-OMe, 95% (20:1)
3j, R = 2-Br, 85% (21:1)
3k, R = 2-Cl, 90% (20:1)
3l, R = 4-Cl, 85% (19:1)
3m, R = 4-F, 91% (15:1)
O
O
S
PO
BnO
O
S
Table 2 Stability of 3a in DCM at Room Temperaturea
BnO
BnO
NO2
NO2
OBn
OBn
Productsb
3na, P = Bn, 68% (17:1)
3nb, P = TIPS, 77% (1:0)
Entry
4e (equiv) Cs2CO3
EtSH
(equiv)
Time
(h)
3o, 72% (11:1)
(equiv)
O
S
O
S
O
S
1
2
3
4
5
6
7
8
0.15
0.15
0.15
0.75
0.75
0.75
0
0.1
0.1
0.1
0.5
0.5
0
0
2
2
2
2
2
2
2
1
1a + 3a (1:18)
3a
PO
BnO
BnO
BnO
PO
BnO
1
NO2
NO2
NO2
OBn
OBn
OBn
24
1
3a + 3a (15:1)
3a + 3a (22:1)
3a + 3a (3:1)
3a
3pa, P = Bn, 82% (1:0)
3pb, P = TIPS, 79% (1:0)
3q, 83% (12:1)
3ra, P = Bn, 83% (12:1)
3rb, P = TIPS, 85% (21:1)
24
24
1
O
O
N
O
S
O
S
O
O
S
0.5
0.5
3a + 3a (8:1)
3a + 3a (1:12)
BnO
BnO
BnO
BnO
BnO
BnO
R
OEt
0
24
NO2
NO2
NO2
OBn
3s, 73% (1:0)
OBn
OBn
a Reaction conditions: 3a (1.0 equiv), 4e, EtSH, Cs2CO3, DCM, r.t., 24 h.
3t, 60% (4:1) (10 h)
3u, R = Ph, 72% (38:1)
3v, R = Tol, 83% (26:1)
b Yields 90–100%; product ratios obtained by 1H NMR spectroscopy.
Scheme 2 NHC-catalyzed stereoselective glycosylation of 2-nitroga-
lactals with thiols and thiophenol. Reagents and conditions: 1 (0.10
mmol), RSH (0.20 mmol), 4e (0.015 mmol), Cs2CO3 (0.010 mmol),
DCM (1.0 mL), r.t., under argon, 24 h; yields shown are for isolated
products; both isomers were separated by flash column chromatogra-
phy.
With the optimized conditions in hand, we tested this
method on a series of thiols (Scheme 2). The reactions all
proceeded smoothly to yield the corresponding S-glyco-
sides in good to excellent yields and high to excellent stere-
© 2019. Thieme. All rights reserved. — Synthesis 2019, 51, A–K

D
Y.-L. Hu et al.
Paper
Synthesis
thiophenols were used as glycosylation acceptors, giving
the desired products 3u and 3v smoothly (3u, 72% yield, /
38:1; 3v, 83% yield, / 26:1).
4e
Cs2CO3
N
N
SMe
MeS
To test the synthetic practicability of this stereoselective
glycosylation method, a scaled-up experiment was carried
out under the optimal reaction conditions, and 3ra was ob-
tained in comparable yield and selectivity (Scheme 3; 83%
yield, / 12:1). To further demonstrate the synthetic prac-
ticability of the newly developed methodology, synthesis of
mycothiol analogue 5 was carried out. Reduction of the ni-
tro group of -thioglycoside 3ra by using Zn/HCl in a mix-
ture of AcOH/THF/H2O, followed by N-acetylation with ace-
tic anhydride in pyridine, furnished the target 5 in 90%
yield over two steps (Scheme 3).21
RSH
3
A
OBn
O
OBn
BnO
Mes
N+
–
S
S–
R
O
H
N
Mes
N
R
H
N
O
N
Mes
B
Mes
1a
C
Scheme 5 Proposed mechanism
In summary, we have described the first NHC-catalyzed
direct and stereoselective thioglycosylation of 2-nitrogalac-
tals to afford -S-linked-2-amino-2-deoxygalactosides in
good to excellent yields and high selectivities under simple
and practicable conditions. The method is widely applica-
ble to a range of nucleophilic acceptors, covering various al-
kanethiols and thiophenols. Furthermore, we have demon-
strated the applicability of the catalytic method in the syn-
thesis of mycothiol analogues. This NHC-catalyzed system
has the potential to be a valuable platform for a wide range
of broadly useful stereocontrolled syntheses of glycopep-
tides, 2-amino sugars, and other bioactive natural or non-
natural products. Further investigations aiming at a better
understanding of the mechanism and extending the scope
as well as application of this glycosylation reaction are un-
derway.
O
O
S
Cs2CO3 (0.15 equiv)
4e (0.15 equiv), CySH
BnO
BnO
BnO
NO2
BnO
NO2
DCM, r.t., 24 h
OBn
OBn
1a (1.08 g)
3ra, 83% (12:1)
O
S
BnO
BnO
i) Zn, HCl, AcOH, THF, H2O, 0 °C, 3 h
ii) Ac2O, pyridine, r.t., 1 h
NHAc
OBn
5, 90%
Scheme 3 Gram-scale preparation of 3ra and synthesis of compound 5
2-Nitroglucal was also examined under the optimal re-
action conditions. Not surprisingly, the desired thioglyco-
side 6 was obtained with -selectivity as the major product,
together with the minor product 7 (Scheme 4). These re-
sults are accordance with our previously proposed mecha-
nism,18 that the C-4 stereocenter is also responsible for the
stereocontrol in this glycosylation reaction.
All reactions that required anhydrous conditions were carried by
standard procedures under argon atmosphere. Commercially avail-
able reagents were used as received. The solvents were dried by distil-
lation over the appropriate drying reagents. IR spectra were recorded
on a TENSOR 27FT-IR spectrophotometer. 1H and 13C NMR spectra
were recorded on a Varian (400 MHz) spectrometer. Chemical shifts
() are reported in ppm relative to TMS ( = 0.00) for the 1H NMR and
chloroform ( = 77.0) for the 13C NMR measurements. High resolution
mass spectra were obtained on an UltiMate 3000 spectrometer. Enan-
tiomeric excesses were determined by HPLC analysis on Dionex Ulti-
Mate 3000 HPLC units, including the following instruments: pump,
LPG-3400SD; detector, VWD-3100; column, Daicel Chiralpak IA, IB,
IC, or ID. Optical rotations were recorded on a Jasco DIP-1000 po-
larimeter. Reactions were followed by TLC (0.254 mm silica gel 60-F
plates). Visualization was accomplished with UV light. Flash chroma-
tography separations were performed on 200–300 mesh silica gel.
OBn
O
Cs2CO3 (0.15 equiv)
OBn
OBn
4e (0.15 equiv), CySH
O
S
O
S
+
BnO
NO2
DCM, r.t., 24 h
OBn
BnO
NO2 BnO
NO2
OBn
OBn
7, 16%
1c
6, 56% (β:α = 3:1)
Scheme 4 Reaction of 2-nitroglucal with cyclohexanethiol
Based on the literature and our previous work, a plausi-
ble mechanism is proposed (Scheme 5). The deprotonation
of imidazolium salt 4e by Cs2CO3 leads to carbene A, which
is also recognized as a carbon-centered Brønsted base. Sub-
sequently, A interacts with the sulfhydryl group via hydro-
gen bonding to give an NHC−HSR complex B, which facili-
tates the Michael addition of the sulfhydryl group to the 2-
nitrogalactal from the sterically favored side. Finally, an -
anomer bearing a C-2 carbanion intermediate was generat-
ed stereoselectively, together with 4e. Then protonation of
the C-2 carbanion intermediate with 4e at the -side leads
to the 1,2-cis-glycoside product and regenerates the NHC
organocatalyst.
NHC-Catalyzed Stereoselective Glycosylation of 2-Nitrogalactal;
General Procedure
A suspension of Cs2CO3 (3.3 mg, 0.010 mmol), 4e (5.1 mg, 0.015
mmol), and tri-O-benzyl-2-nitrogalactal (1a; 46 mg, 0.10 mmol, 1.0
equiv) in anhydrous DCM (1.0 mL, 0.01 M) was stirred in a Schlenk
flask under an argon atmosphere at room temperature for 0.5 h. To
the mixture was added the appropriate RSH (0.20 mmol, 2.0 equiv) in
one portion. The reaction mixture was stirred until the consumption
© 2019. Thieme. All rights reserved. — Synthesis 2019, 51, A–K

E
Y.-L. Hu et al.
Paper
Synthesis
of 1a, as monitored by TLC. Upon completion of the reaction, the sol-
vent was removed under reduced pressure. The residue was purified
by flash column chromatography (silica gel, n-hexane/EtOAc) to yield
the corresponding product 3.
13C NMR (100 MHz, CDCl3):  = 137.98, 137.16, 128.53, 128.31,
128.30, 128.16, 128.12, 127.79, 84.50, 81.68, 75.92, 75.18, 73.38,
73.24, 71.78, 61.74, 32.91, 22.68, 17.94, 13.29, 11.76.
HRMS (ESI): m/z [M + Na]+ calcd for C32H49NO6SSiNa: 626.2942;
found: 626.2930.
Ethyl 3,4,6-Tri-O-benzyl-2-deoxy-2-nitro-1-thio-D-galactopyrano-
side (3a, 3a)
3-Methylbutyl 3,4,6-Tri-O-benzyl-2-deoxy-2-nitro-1-thio-D-galac-
topyranoside (3c, 3c)
Yield: 3a: 41 mg (79%) and 3a: 3 mg (6%); clear oils.
Yield: 3c: 47 mg (83%) and 3c: 3 mg (4%); clear oils.
3a
[]D24 +12.9 (c 2.0, CHCl3).
3c
IR (KBr): 2922, 2360, 1552, 1357, 1062, 739 cm–1
.
[]D22 +12.5 (c 1.0, CHCl3).
1H NMR (400 MHz, CDCl3):  = 7.39–7.19 (m, 15 H), 5.73 (d, J = 6.0 Hz,
1 H), 5.28 (dd, J = 10.8, 6.0 Hz, 1 H), 4.84 (d, J = 11.1 Hz, 1 H), 4.71 (s, 2
H), 4.51–4.41 (m, 3 H), 4.40–4.35 (m, 1 H), 4.29 (dd, J = 10.8, 2.5 Hz, 1
H), 4.03–3.99 (m, 1 H), 3.62–3.50 (m, 2 H), 2.67–2.50 (m, 2 H), 1.24 (t,
J = 7.2 Hz, 3 H).
13C NMR (100 MHz, CDCl3):  = 137.87, 137.67, 137.09, 128.51,
128.44, 128.34, 128.18, 128.13, 127.85, 127.76, 84.35, 81.50, 75.93,
75.18, 73.50, 73.38, 73.11, 69.93, 68.24, 25.16, 14.53.
IR (KBr): 2953, 1570, 1373, 1068, 734, 673 cm–1
.
1H NMR (400 MHz, CDCl3):  = 7.39–7.18 (m, 15 H), 5.71 (d, J = 5.8 Hz,
1 H), 5.28 (dd, J = 10.4, 6.3 Hz, 1 H), 4.84 (d, J = 11.1 Hz, 1 H), 4.75–4.67
(m, 2 H), 4.52–4.34 (m, 4 H), 4.29 (d, J = 10.8 Hz, 1 H), 4.00 (s, 1 H),
3.62–3.49 (m, 2 H), 2.66–2.49 (m, 2 H), 1.69–1.54 (m, 1 H), 1.49–1.40
(m, 2 H), 0.85 (dd, J = 6.3, 3.7 Hz, 6 H).
13C NMR (101 MHz, CDCl3):  = 137.78, 137.57, 136.97, 128.48,
128.40, 128.31, 128.15, 128.12, 128.09, 127.83, 127.73, 84.30, 81.68,
75.84, 75.11, 73.43, 73.24, 73.04, 69.87, 68.18, 37.98, 29.03, 27.17,
22.18, 22.03.
HRMS (ESI): m/z [M + Na]+ calcd for C29H33NO6SNa: 546.1921; found:
546.1922.
HRMS (ESI): m/z [M + Na]+ calcd for C32H39NO6SNa: 588.2390; found:
588.2385.
n-Propyl 3,4,6-Tri-O-benzyl-2-deoxy-2-nitro-1-thio-D-galactopy-
ranoside (3ba, 3ba)
Yield: 3ba: 41 mg (77%) and 3ba: 2 mg (4%); clear oils.
1-Heptyl 3,4,6-Tri-O-benzyl-2-deoxy-2-nitro-1-thio-D-galactopy-
ranoside (3d, 3d)
3ba
Yield: 3d: 51 mg (86%) and 3d: 3 mg (4%); clear oils.
[]D24 +8.8 (c 0.5, CHCl3).
IR (KBr): 2938, 1907, 1554, 1099, 734, 688 cm–1
.
3d
[]D22 +8.2 (c 1.0, CHCl3).
IR (KBr): 2938, 1601, 1053, 795, 689 cm–1
1H NMR (400 MHz, CDCl3):  = 7.38–7.21 (m, 15 H), 5.71 (d, J = 6.0 Hz,
1 H), 5.28 (dd, J = 10.8, 6.0 Hz, 1 H), 4.84 (d, J = 11.1 Hz, 1 H), 4.75–4.69
(m, 2 H), 4.47 (dd, J = 11.4, 5.9 Hz, 2 H), 4.42 (d, J = 11.7 Hz, 1 H), 4.37
(t, J = 6.5 Hz, 1 H), 4.29 (dd, J = 10.9, 2.9 Hz, 1 H), 4.01 (d, J = 2.5 Hz, 1
H), 3.60–3.52 (m, 2 H), 2.63–2.47 (m, 2 H), 1.65–1.57 (m, 2 H), 0.93 (t,
J = 7.3 Hz, 3 H).
13C NMR (100 MHz, CDCl3):  = 137.88, 137.69, 137.11, 128.51,
128.43, 128.34, 128.19, 128.12, 127.84, 127.73, 84.39, 81.90, 75.90,
75.17, 73.48, 73.40, 73.12, 69.95, 68.28, 33.15, 22.68, 13.29.
.
1H NMR (400 MHz, CDCl3):  = 7.38–7.22 (m, 15 H), 5.71 (d, J = 6.0 Hz,
1 H), 5.28 (dd, J = 10.8, 6.0 Hz, 1 H), 4.84 (d, J = 11.1 Hz, 1 H), 4.75–4.68
(m, 2 H), 4.47 (dd, J = 11.4, 5.3 Hz, 2 H), 4.43 (s, 1 H), 4.38 (dd, J = 11.5,
4.9 Hz, 1 H), 4.29 (dd, J = 10.9, 2.9 Hz, 1 H), 4.01 (d, J = 2.5 Hz, 1 H),
3.61–3.51 (m, 2 H), 2.64–2.49 (m, 2 H), 1.60–1.51 (m, 2 H), 1.32–1.19
(m, 8 H), 0.87 (t, J = 6.8 Hz, 3 H).
13C NMR (101 MHz, CDCl3):  = 137.79, 137.59, 137.03, 128.49,
128.41, 128.32, 128.16, 128.13, 128.09, 127.83, 127.73, 84.31, 81.78,
75.84, 75.12, 73.44, 73.23, 73.05, 69.84, 68.19, 31.61, 31.06, 29.21,
28.72, 28.61, 22.54, 14.07.
HRMS (ESI): m/z [M + Na]+ calcd for C30H35NO6SNa: 560.2077; found:
560.2071.
HRMS (ESI): m/z [M + Na]+ calcd for C34H43NO6SNa: 616.2703; found:
n-Propyl 3,4-Di-O-benzyl-2-deoxy-2-nitro-6-O-triisopropylsilyl-
8-D-galactopyranoside (3bb)
616.2714.
Yield: 44 mg (73%); clear oil.
2-Phenylethyl 3,4,6-Tri-O-benzyl-2-deoxy-2-nitro-1-thio-D-galac-
topyranoside (3ea, 3ea)
3bb
[]D22 +9.7 (c 1.0, CHCl3).
Yield: 3ea: 42 mg (71%) and 3ea: 2 mg (4%); clear oils.
IR (KBr): 2923, 2376, 1556, 1114, 734, 688 cm–1
.
3ea
1H NMR (400 MHz, CDCl3):  = 7.40–7.26 (m, 10 H), 5.71 (d, J = 6.0 Hz,
1 H), 5.28 (dd, J = 10.8, 6.0 Hz, 1 H), 4.85 (d, J = 11.1 Hz, 1 H), 4.77 (d,
J = 10.8 Hz, 1 H), 4.72 (d, J = 10.9 Hz, 1 H), 4.53 (d, J = 11.1 Hz, 1 H),
4.33 (dd, J = 10.8, 2.7 Hz, 1 H), 4.20 (t, J = 6.5 Hz, 1 H), 3.97 (d, J = 2.3
Hz, 1 H), 3.73 (d, J = 6.5 Hz, 2 H), 2.64–2.48 (m, 2 H), 1.65–1.56 (m, 2
H), 1.10–1.03 (m, 21 H), 0.95 (t, J = 7.3 Hz, 3 H).
[]D21 +5.8 (c 3.0, CHCl3).
IR (KBr): 3014, 1540, 1114, 1084, 750, 689 cm–1
1H NMR (400 MHz, CDCl3):  = 7.35–7.24 (m, 15 H), 7.24–7.19 (m, 3
H), 7.14 (d, J = 7.1 Hz, 2 H), 5.71 (d, J = 6.0 Hz, 1 H), 5.27 (dd, J = 10.9,
6.0 Hz, 1 H), 4.84 (d, J = 11.2 Hz, 1 H), 4.71 (s, 2 H), 4.48 (d, J = 3.1 Hz, 1
.
© 2019. Thieme. All rights reserved. — Synthesis 2019, 51, A–K

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Y.-L. Hu et al.
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Synthesis
H), 4.45 (d, J = 2.5 Hz, 1 H), 4.40 (d, J = 11.7 Hz, 1 H), 4.34 (t, J = 6.4 Hz,
1 H), 4.28 (dd, J = 10.9, 2.7 Hz, 1 H), 4.00 (d, J = 2.1 Hz, 1 H), 3.59–3.49
(m, 2 H), 2.90–2.75 (m, 4 H).
13C NMR (100 MHz, CDCl3):  = 139.78, 137.78, 137.58, 137.03,
128.51, 128.47, 128.44, 128.35, 128.17, 128.13, 127.88, 127.87,
127.78, 126.48, 84.29, 81.84, 75.85, 75.17, 73.52, 73.29, 73.11, 70.03,
68.28, 35.92, 32.31.
1H NMR (400 MHz, CDCl3):  = 7.37–7.18 (m, 15 H), 7.13 (d, J = 7.9 Hz,
2 H), 7.06 (d, J = 8.0 Hz, 2 H), 5.52 (d, J = 6.0 Hz, 1 H), 5.22 (dd, J = 10.8,
6.0 Hz, 1 H), 4.82 (d, J = 11.2 Hz, 1 H), 4.68 (s, 2 H), 4.49–4.40 (m, 3 H),
4.36 (t, J = 6.4 Hz, 1 H), 4.31 (dd, J = 10.9, 2.7 Hz, 1 H), 3.99 (d, J = 2.4
Hz, 1 H), 3.74 (d, J = 13.2 Hz, 1 H), 3.64 (d, J = 13.2 Hz, 1 H), 3.58–3.51
(m, 1 H), 3.44 (dd, J = 9.2, 6.1 Hz, 1 H), 2.30 (s, 3 H).
13C NMR (101 MHz, CDCl3):  = 137.70, 137.61, 136.97, 136.95,
133.25, 129.19, 128.89, 128.48, 128.44, 128.31, 128.17, 128.13,
128.09, 127.85, 127.75, 84.08, 79.86, 76.12, 75.07, 73.47, 73.17, 73.02,
69.94, 68.27, 33.85, 21.08.
HRMS (ESI): m/z [M + Na]+ calcd for C35H37NO6SNa: 622.2234; found:
622.2238.
HRMS (ESI): m/z [M + Na]+ calcd for C35H37NO6SNa: 622.2234; found:
622.2241.
2-Phenylethyl 3,4-Di-O-benzyl-2-deoxy-2-nitro-6-O-triisopropyl-
silyl-8-D-galactopyranoside (3eb, 3eb)
Yield: 3eb: 49 mg (72%) and 3eb: 2 mg (3%); clear oils.
4- tert-Butylbenzyl 3,4,6-Tri-O-benzyl-2-deoxy-2-nitro-1-thio-D-
galactopyranoside (3h, 3h)
3eb
Yield: 3h: 51 mg (80%) and 3h: 3 mg (5%); clear oils.
[]D21 +7.7 (c 1.0, CHCl3).
IR (KBr): 3021, 1531, 1099, 1003, 738, 682 cm–1
.
3h
1H NMR (400 MHz, CDCl3):  = 7.35–7.26 (m, 12 H), 7.24–7.12 (m, 3
H), 5.68 (d, J = 6.0 Hz, 1 H), 5.27 (dd, J = 10.3, 5.4 Hz, 1 H), 4.84 (d, J =
11.1 Hz, 1 H), 4.75 (d, J = 10.8 Hz, 1 H), 4.70 (d, J = 10.8 Hz, 1 H), 4.52
(d, J = 11.1 Hz, 1 H), 4.30 (dd, J = 10.9, 2.9 Hz, 1 H), 4.18 (t, J = 6.5 Hz, 1
H), 3.96 (d, J = 2.5 Hz, 1 H), 3.73 (d, J = 6.6 Hz, 2 H), 2.90–2.75 (m, 4 H),
1.05–1.00 (m, 21 H).
13C NMR (100 MHz, CDCl3):  = 139.71, 137.91, 137.10, 128.54,
128.49, 128.43, 128.33, 128.30, 128.19, 128.15, 127.83, 126.48, 84.42,
81.67, 75.88, 75.19, 73.29, 73.24, 71.89, 61.73, 36.01, 32.05, 17.94,
11.74.
[]D22 +14.9 (c 2.0, CHCl3).
IR (KBr): 2953, 1554, 1129, 765, 704 cm–1
.
1H NMR (400 MHz, CDCl3):  = 7.36–7.24 (m, 15 H), 7.21–7.16 (m, 4
H), 5.55 (d, J = 5.8 Hz, 1 H), 5.23 (dd, J = 10.6, 6.0 Hz, 1 H), 4.82 (d, J =
11.2 Hz, 1 H), 4.68 (s, 2 H), 4.50–4.30 (m, 5 H), 3.98 (s, 1 H), 3.75 (d, J =
13.3 Hz, 1 H), 3.66 (d, J = 13.2 Hz, 1 H), 3.58–3.46 (m, 2 H), 1.29 (s, 9
H).
13C NMR (101 MHz, CDCl3):  = 150.22, 137.72, 137.61, 136.95,
133.23, 128.67, 128.49, 128.45, 128.32, 128.17, 128.15, 128.11,
127.86, 127.76, 84.11, 79.90, 76.13, 75.08, 73.49, 73.21, 73.05, 69.94,
68.34, 34.44, 33.76, 31.26.
HRMS (ESI): m/z [M + Na]+ calcd for C37H51NO6SSiNa: 688.3099;
found: 688.3105.
HRMS (ESI): m/z [M + Na]+ calcd for C38H43NO6SNa: 664.2703; found:
664.2698.
Benzyl 3,4,6-Tri-O-benzyl-2-deoxy-2-nitro-1-thio-D-galactopyra-
noside (3f, 3f)
4-Methoxybenzyl 3,4,6-Tri-O-benzyl-2-deoxy-2-nitro-1-thio-D-ga-
lactopyranoside (3i, 3i)
Yield: 3f: 46 mg (79%) and 3f: 3 mg (5%); clear oils.
Yield: 3i: 56 mg (90%) and 3i: 3 mg (5%); clear oils.
3f
[]D24 +46.4 (c 1.0, CHCl3).
IR (KBr): 2920, 1551, 1463, 1335, 1267, 752 cm–1
3i
.
[]D25 +23.4 (c 2.0, CHCl3).
IR (KBr): 2922, 1560, 1460, 1375, 752 cm–1
1H NMR (400 MHz, CDCl3):  = 7.40–7.15 (m, 20 H), 5.54 (d, J = 6.0 Hz,
1 H), 5.23 (dd, J = 10.8, 6.0 Hz, 1 H), 4.82 (d, J = 11.2 Hz, 1 H), 4.68 (s, 2
H), 4.49–4.38 (m, 3 H), 4.38–4.23 (m, 2 H), 3.99 (d, J = 2.3 Hz, 1 H),
3.81–3.67 (m, 2 H), 3.62–3.49 (m, 1 H), 3.44–3.34 (m, 1 H).
13C NMR (101 MHz, CDCl3):  = 137.78, 137.67, 137.02, 136.54,
128.99, 128.52, 128.49, 128.45, 128.32, 128.15, 128.11, 127.86,
127.78, 127.32, 84.16, 80.13, 76.15, 75.12, 73.51, 73.32, 73.09, 70.09,
68.29, 34.30.
.
1H NMR (400 MHz, CDCl3):  = 7.38–7.13 (m, 17 H), 6.79 (d, J = 8.5 Hz,
2 H), 5.52 (d, J = 6.0 Hz, 1 H), 5.22 (dd, J = 10.8, 6.0 Hz, 1 H), 4.82 (d, J =
11.2 Hz, 1 H), 4.68 (s, 2 H), 4.50–4.39 (m, 3 H), 4.37 (t, J = 6.4 Hz, 1 H),
4.35–4.24 (m, 1 H), 4.07–3.92 (m, 1 H), 3.79–3.77 (m, 3 H), 3.73–3.62
(m, 2 H), 3.58–3.44 (m, 2 H).
13C NMR (100 MHz, CDCl3):  = 158.80, 137.76, 137.67, 137.01,
130.16, 128.49, 128.45, 128.32, 128.27, 128.17, 128.14, 128.10,
127.86, 127.76, 113.91, 84.13, 79.89, 76.18, 75.10, 73.51, 73.31, 73.07,
70.06, 68.40, 55.21, 33.63.
HRMS (ESI): m/z [M + Na]+ calcd for C34H35NO6SNa: 608.2077; found:
608.2073.
HRMS (ESI): m/z [M + Na]+ calcd for C35H37NO7SNa: 638.2183; found:
638.2179.
4-Methylbenzyl 3,4,6-Tri-O-benzyl-2-deoxy-2-nitro-1-thio-D-ga-
lactopyranoside (3g, 3g)
Yield: 3g: 52 mg (87%) and 3g: 3 mg (5%); clear oils.
2-Bromobenzyl 3,4,6-Tri-O-benzyl-2-deoxy-2-nitro-1-thio-D-ga-
lactopyranoside (3j, 3j)
3g
Yield: 3j: 54 mg (81%) and 3j: 3 mg (4%); clear oils.
[]D20 +13.2 (c 1.0, CHCl3).
IR (KBr): 3044, 1585, 1220, 764, 673 cm–1
.
3j
[]D25 +12.6 (c 2.0, CHCl3).
© 2019. Thieme. All rights reserved. — Synthesis 2019, 51, A–K

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Y.-L. Hu et al.
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Synthesis
IR (KBr): 3075, 1555, 1113, 734, 673 cm–1
.
3m
[]D24 +21.7 (c 2.0, CHCl3).
IR (KBr): 2922, 2360, 1552, 1388, 1267, 1064, 748 cm–1
1H NMR (400 MHz, CDCl3):  = 7.50 (d, J = 7.9 Hz, 1 H), 7.38–7.25 (m,
15 H), 7.23–7.15 (m, 2 H), 7.07 (t, J = 7.6 Hz, 1 H), 5.66 (d, J = 5.9 Hz, 1
H), 5.26 (dd, J = 10.9, 5.9 Hz, 1 H), 4.82 (d, J = 11.2 Hz, 1 H), 4.68 (s, 2
H), 4.46 (d, J = 11.2 Hz, 1 H), 4.42 (s, 2 H), 4.36 (t, J = 6.4 Hz, 1 H), 4.30
(dd, J = 10.9, 1.7 Hz, 1 H), 4.01 (s, 1 H), 3.89 (d, J = 13.3 Hz, 1 H), 3.84
(d, J = 13.3 Hz, 1 H), 3.54 (t, J = 8.2 Hz, 1 H), 3.38 (dd, J = 8.8, 6.0 Hz, 1
H).
13C NMR (101 MHz, CDCl3):  = 137.70, 137.57, 136.92, 136.04,
133.08, 130.99, 129.00, 128.48, 128.44, 128.32, 128.21, 128.12,
128.10, 127.87, 127.80, 127.39, 124.47, 84.08, 80.55, 75.98, 75.14,
73.45, 73.09, 73.03, 69.94, 67.92, 34.86.
.
1H NMR (400 MHz, CDCl3):  = 7.39–7.16 (m, 17 H), 6.94 (t, J = 8.4 Hz,
2 H), 5.50 (d, J = 5.7 Hz, 1 H), 5.23 (dd, J = 10.1, 6.2 Hz, 1 H), 4.82 (d, J =
11.2 Hz, 1 H), 4.69 (s, 2 H), 4.50–4.39 (m, 3 H), 4.37–4.27 (m, 2 H),
3.99 (s, 1 H), 3.76–3.65 (m, 2 H), 3.57–3.40 (m, 2 H).
13C NMR (101 MHz, CDCl3):  = 162.00 (d, J = 246.1 Hz), 137.67 (d, J =
10.1 Hz), 136.98, 132.24 (d, J = 2.9 Hz), 130.62 (d, J = 8.1 Hz), 128.52,
128.48, 128.36, 128.19, 128.16, 127.91, 127.80, 115.42 (d, J = 21.5 Hz),
84.10, 79.95, 76.15, 75.13, 73.56, 73.29, 73.13, 70.22, 68.42, 33.45.
HRMS (ESI): m/z [M + Na]+ calcd for C34H34FNO6SNa: 626.1983; found:
626.1976.
HRMS (ESI): m/z [M + Na]+ calcd for C34H34BrNO6SNa: 686.1182;
found: 686.1180.
Allyl 3,4,6-Tri-O-benzyl-2-deoxy-2-nitro-1-thio-D-galactopyrano-
side (3na, 3na)
2-Chlorobenzyl 3,4,6-Tri-O-benzyl-2-deoxy-2-nitro-1-thio-D-ga-
lactopyranoside (3k, 3k)
Yield: 3na: 34 mg (64%) and 3na: 2 mg (4%); clear oils.
Yield: 3k: 53 mg (86%) and 3k: 3 mg (4%); clear oils.
3na
3k
[]D24 +7.5 (c 0.5, CHCl3).
IR (KBr): 2920, 1625, 1458, 1373, 1066, 734 cm–1
[]D22 +15.4 (c 1.0, CHCl3).
IR (KBr): 3029, 1570, 1220, 1114, 779, 673 cm–1
.
.
1H NMR (400 MHz, CDCl3):  = 7.47–7.29 (m, 15 H), 5.84–5.76 (m, 1
H), 5.73 (d, J = 6.0 Hz, 1 H), 5.70 (dd, J = 10.8, 6.0 Hz, 1 H), 5.21 (d, J =
3.2 Hz, 1 H), 5.18 (s, 1 H), 4.91 (d, J = 11.2 Hz, 1 H), 4.78 (s, 2 H), 4.57–
4.52 (m, 3 H), 4.43 (t, J = 6.4 Hz, 1 H), 4.38 (dd, J = 10.8, 2.8 Hz, 1 H),
4.09 (d, J = 2.0 Hz, 1 H), 3.71–3.57 (m, 2 H), 3.32–3.22 (m, 1 H), 3.21–
3.14 (m, 1 H).
13C NMR (100 MHz, CDCl3):  = 137.77, 137.62, 137.01, 132.24,
128.47, 128.41, 128.30, 128.12, 128.08, 127.83, 127.72, 118.62, 84.14,
79.76, 76.14, 75.11, 73.46, 73.27, 73.04, 70.10, 68.27, 32.73.
1H NMR (400 MHz, CDCl3):  = 7.37–7.26 (m, 15 H), 7.23–7.19 (m, 2
H), 7.18–7.10 (m, 2 H), 5.65 (d, J = 5.9 Hz, 1 H), 5.26 (dd, J = 11.3, 5.4
Hz, 1 H), 4.82 (d, J = 11.2 Hz, 1 H), 4.67 (s, 2 H), 4.46 (d, J = 11.1 Hz, 1
H), 4.41 (d, J = 12.7 Hz, 2 H), 4.35 (t, J = 6.5 Hz, 1 H), 4.30 (dd, J = 10.9,
1.3 Hz, 1 H), 4.01 (s, 1 H), 3.88 (d, J = 13.3 Hz, 1 H), 3.84 (d, J = 13.5 Hz,
1 H), 3.54 (t, J = 8.2 Hz, 1 H), 3.38 (dd, J = 8.7, 6.1 Hz, 1 H).
13C NMR (100 MHz, CDCl3):  = 137.70, 137.58, 136.92, 134.41,
134.05, 130.95, 129.77, 128.80, 128.48, 128.43, 128.32, 128.20,
128.13, 128.10, 127.87, 127.86, 127.78, 126.74, 84.09, 80.52, 75.98,
75.14, 73.45, 73.10, 73.03, 69.91, 67.95, 32.09.
HRMS (ESI): m/z [M + Na]+ calcd for C30H33NO6SNa: 558.1921; found:
558.1913.
HRMS (ESI): m/z [M + Na]+ calcd for C34H34ClNO6SNa: 642.1688;
found: 642.1701.
Allyl 3,4-Di-O-benzyl-2-deoxy-2-nitro-6-O-triisopropylsilyl-8-D-
galactopyranoside (3nb)
4-Chlorobenzyl 3,4,6-Tri-O-benzyl-2-deoxy-2-nitro-1-thio-D-ga-
lactopyranoside (3l, 3l)
Yield: 3nb: 46 mg (77%); clear oil.
Yield: 3l: 50 mg (81%) and 3l: 3 mg (4%); clear oils.
3nb
[]D22 +8.5 (c 1.0, CHCl3).
IR (KBr): 2968, 2847, 1549, 1068, 734, 659 cm–1
3l
[]D25 +19.2 (c 2.0, CHCl3).
.
1H NMR (400 MHz, CDCl3):  = 7.37–7.25 (m, 10 H), 5.75–5.69 (m, 1
H), 5.65 (d, J = 6.1 Hz, 1 H), 5.30 (dd, J = 10.6, 6.3 Hz, 1 H), 5.14 (s, 1 H),
5.11 (d, J = 4.6 Hz, 1 H), 4.84 (d, J = 11.1 Hz, 1 H), 4.75 (d, J = 10.8 Hz, 1
H), 4.71 (d, J = 10.8 Hz, 1 H), 4.52 (d, J = 11.2 Hz, 1 H), 4.33 (dd, J = 10.9,
2.9 Hz, 1 H), 4.18 (t, J = 6.5 Hz, 1 H), 3.96 (d, J = 2.5 Hz, 1 H), 3.77–3.67
(m, 2 H), 3.23 (dd, J = 13.7, 8.9 Hz, 1 H), 3.10 (dd, J = 13.7, 5.5 Hz, 1 H),
1.08–0.98 (m, 21 H).
13C NMR (100 MHz, CDCl3):  = 137.91, 137.10, 132.30, 128.54,
128.33, 128.29, 128.17, 127.83, 118.60, 84.30, 79.65, 76.24, 75.13,
73.31, 73.24, 72.05, 61.97, 32.48, 17.95, 11.77.
IR (KBr): 2922, 1554, 1498, 1361, 1097, 742 cm–1
.
1H NMR (400 MHz, CDCl3):  = 7.35–7.16 (m, 19 H), 5.51 (d, J = 5.9 Hz,
1 H), 5.23 (dd, J = 10.6, 6.0 Hz, 1 H), 4.82 (d, J = 11.2 Hz, 1 H), 4.68 (s, 2
H), 4.52–4.36 (m, 3 H), 4.30 (d, J = 7.3 Hz, 2 H), 3.98 (s, 1 H), 3.75–3.62
(m, 2 H), 3.53–3.38 (m, 2 H).
13C NMR (100 MHz, CDCl3):  = 137.71, 137.61, 136.96, 135.17,
133.14, 130.36, 128.69, 128.52, 128.48, 128.35, 128.18, 128.15,
127.92, 127.80, 84.08, 80.03, 76.12, 75.13, 73.56, 73.26, 73.13, 70.22,
68.37, 33.56.
HRMS (ESI): m/z [M + Na]+ calcd for C34H34ClNO6SNa: 642.1688;
found: 642.1677.
HRMS (ESI): m/z [M + Na]+ calcd for C32H47NO6SSiNa: 624.2786;
found: 624.2770.
4-Fluorobenzyl 3,4,6-Tri-O-benzyl-2-deoxy-2-nitro-1-thio-D-ga-
lactopyranoside (3m, 3m)
2-Furylmethyl 3,4,6-Tri-O-benzyl-2-deoxy-2-nitro-1-thio-D-galac-
topyranoside (3o, 3o)
Yield: 3m: 51 mg (85%) and 3m: 3 mg (6%); clear oils.
Yield: 3o: 38 mg (66%) and 3o: 3 mg (6%); clear oils.
© 2019. Thieme. All rights reserved. — Synthesis 2019, 51, A–K

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Y.-L. Hu et al.
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Synthesis
3o
1H NMR (400 MHz, CDCl3):  = 7.37–7.19 (m, 15 H), 5.75 (d, J = 6.0 Hz,
1 H), 5.27 (dd, J = 10.8, 6.0 Hz, 1 H), 4.84 (d, J = 11.1 Hz, 1 H), 4.75–4.67
(m, 2 H), 4.50–4.37 (m, 4 H), 4.26 (dd, J = 10.8, 2.5 Hz, 1 H), 4.00 (d, J =
1.5 Hz, 1 H), 3.62–3.52 (m, 2 H), 3.18–3.10 (m, 1 H), 2.05–1.91 (m, 2
H), 1.73–1.64 (m, 2 H), 1.58–1.45 (m, 4 H).
13C NMR (100 MHz, CDCl3):  = 137.83, 137.63, 137.05, 128.49,
128.40, 128.31, 128.18, 128.11, 128.08, 127.82, 127.70, 75.86, 75.14,
73.42, 73.30, 73.04, 69.92, 68.13, 43.84, 33.79, 33.47, 24.63, 24.25.
[]D24 +20.4 (c 2.0, CHCl3).
IR (KBr): 2922, 1553, 1458, 1349, 1064, 744 cm–1
.
1H NMR (400 MHz, CDCl3):  = 7.48–7.26 (m, 16 H), 6.36–6.32 (m, 1
H), 6.23 (d, J = 2.4 Hz, 1 H), 5.78 (d, J = 6.0 Hz, 1 H), 5.36 (dd, J = 10.8,
6.0 Hz, 1 H), 4.91 (d, J = 11.2 Hz, 1 H), 4.77 (s, 2 H), 4.56–4.50 (m, 3 H),
4.40–4.36 (m, 2 H), 4.09 (s, 1 H), 3.92 (d, J = 14.8 Hz, 1 H), 3.76 (d, J =
14.8 Hz, 1 H), 3.70–3.55 (m, 2 H).
13C NMR (100 MHz, CDCl3):  = 149.73, 142.51, 137.78, 137.64,
136.99, 128.50, 128.44, 128.33, 128.14, 127.86, 127.78, 110.43,
108.29, 84.12, 80.53, 76.09, 75.14, 73.49, 73.25, 73.08, 70.19, 68.18,
26.42.
HRMS (ESI): m/z [M + Na]+ calcd for C32H37NO6SNa: 586.2234; found:
586.2242.
Cyclohexyl 3,4,6-Tri-O-benzyl-2-deoxy-2-nitro-1-thio-D-galacto-
pyranoside (3ra, 3ra)
HRMS (ESI): m/z [M + Na]+ calcd for C32H33NO7SNa: 598.1870; found:
598.1861.
Yield: 3ra: 44 mg (77%) and 3ra: 3 mg (6%); clear oils.
3ra
Isopropyl 3,4,6-Tri-O-benzyl-2-deoxy-2-nitro-1-thio--D-galacto-
pyranoside (3pa)
[]D24 +38.2 (c 1.0, CHCl3).
IR (KBr): 2920, 1536, 1438, 1381, 1269, 754 cm–1
.
Yield: 44 mg (82%); clear oil; []D24 +14.1 (c 0.5, CHCl3).
1H NMR (400 MHz, CDCl3):  = 7.49–7.06 (m, 15 H), 5.80 (d, J = 6.1 Hz,
1 H), 5.26 (dd, J = 10.9, 6.0 Hz, 1 H), 4.84 (d, J = 11.2 Hz, 1 H), 4.79–4.88
(m, 2 H), 4.47–4.39 (m, 4 H), 4.26 (dd, J = 10.9, 3.0 Hz, 1 H), 3.99 (d, J =
2.3 Hz, 1 H), 3.61–3.52 (m, 2 H), 2.85–2.70 (m, 1 H), 1.97–1.87 (m, 2
H), 1.75–1.65 (m, 2 H), 1.41–1.16 (m, 6 H).
13C NMR (100 MHz, CDCl3):  = 137.93, 137.72, 137.16, 128.51,
128.42, 128.33, 128.20, 128.09, 127.81, 127.70, 84.36, 80.90, 75.94,
75.17, 73.49, 73.44, 73.13, 69.95, 68.28, 44.15, 33.85, 33.23, 25.85,
25.69, 25.55.
IR (KBr): 2922, 1625, 1560, 1381, 1062, 739, 582 cm–1
.
1H NMR (400 MHz, CDCl3):  = 7.38–7.20 (m, 15 H), 5.78 (d, J = 6.1 Hz,
1 H), 5.27 (dd, J = 10.9, 6.1 Hz, 1 H), 4.84 (d, J = 11.1 Hz, 1 H), 4.78–4.67
(m, 2 H), 4.47–4.36 (m, 4 H), 4.26 (dd, J = 10.9, 3.0 Hz, 1 H), 4.00 (d, J =
2.3 Hz, 1 H), 3.62–3.51 (m, 2 H), 3.08–2.97 (m, 1 H), 1.28–1.26 (m, 6
H).
13C NMR (100 MHz, CDCl3):  = 137.92, 137.71, 137.15, 128.51,
128.44, 128.34, 128.21, 127.84, 127.73, 84.33, 80.95, 75.97, 75.21,
73.49, 73.45, 73.13, 69.97, 68.20, 35.80, 23.64, 23.23.
HRMS (ESI): m/z [M + Na]+ calcd for C33H39NO6SNa: 600.2390; found:
600.2379.
HRMS (ESI): m/z [M + Na]+ calcd for C30H35NO6SNa: 560.2077; found:
560.2078.
Cyclohexyl 3,4-Di-O-benzyl-2-deoxy-2-nitro-6-O-triisopropylsi-
lyl-8-D-galactopyranoside (3rb, 3rb)
Isopropyl 3,4-Di-O-benzyl-2-deoxy-2-nitro-6-O-triisopropylsilyl-
8-D-galactopyranoside (3pb)
Yield: 48 mg (79%); clear oil; []D21 +10.2 (c 1.0, CHCl3).
Yield: 3rb: 52 mg (82%) and 3rb: 3 mg (3%); clear oils.
IR (KBr): 2893, 1554, 1448, 1053, 734, 688 cm–1
.
3rb
1H NMR (400 MHz, CDCl3):  = 7.36–7.26 (m, 10 H), 5.79 (d, J = 6.1 Hz,
1 H), 5.28 (dd, J = 10.9, 6.0 Hz, 1 H), 4.84 (d, J = 11.1 Hz, 1 H), 4.76 (d,
J = 10.9 Hz, 1 H), 4.71 (d, J = 10.9 Hz, 1 H), 4.52 (d, J = 11.1 Hz, 1 H),
4.29 (dd, J = 10.9, 3.0 Hz, 1 H), 4.20 (d, J = 6.6 Hz, 1 H), 3.96 (d, J = 2.5
Hz, 1 H), 3.72 (d, J = 6.6 Hz, 2 H), 3.08–3.01 (m, 1 H), 1.26 (d, J = 6.8 Hz,
6 H), 1.09–1.03 (m, 21 H).
13C NMR (100 MHz, CDCl3):  = 138.03, 137.22, 128.53, 128.32,
128.16, 128.13, 127.79, 84.44, 80.59, 76.02, 75.21, 73.46, 73.26, 71.84,
61.73, 35.36, 23.54, 23.20, 17.94, 11.79.
[]D21 +12.4 (c 1.0, CHCl3).
IR (KBr): 2968, 1554, 1266, 1053, 749, 673 cm–1
.
1H NMR (400 MHz, CDCl3):  = 7.39–7.24 (m, 10 H), 5.79 (d, J = 6.0 Hz,
1 H), 5.26 (dd, J = 10.9, 6.0 Hz, 1 H), 4.83 (d, J = 11.1 Hz, 1 H), 4.76 (d,
J = 10.9 Hz, 1 H), 4.71 (d, J = 10.9 Hz, 1 H), 4.52 (d, J = 11.1 Hz, 1 H),
4.28 (dd, J = 10.9, 2.9 Hz, 1 H), 4.22 (t, J = 6.5 Hz, 1 H), 3.95 (d, J = 2.6
Hz, 1 H), 3.73 (d, J = 6.7 Hz, 2 H), 2.90–2.75 (m, 1 H), 1.91 (t, J = 13.4
Hz, 2 H), 1.76–1.65 (m, 2 H), 1.54 (s, 1 H), 1.39–1.24 (m, 5 H), 1.07–
1.02 (m, 21 H).
13C NMR (100 MHz, CDCl3):  = 138.03, 137.22, 128.52, 128.30,
128.13, 128.10, 127.76, 84.44, 80.68, 75.94, 75.21, 73.47, 73.24, 71.79,
61.69, 43.76, 33.80, 33.21, 25.81, 25.59, 25.55, 17.95, 17.93, 11.76.
HRMS (ESI): m/z [M + Na]+ calcd for C32H49NO6SSiNa: 626.2942;
found: 626.2955.
Cyclopentyl 3,4,6-Tri-O-benzyl-2-deoxy-2-nitro-1-thio-D-galacto-
pyranoside (3q, 3q)
HRMS (ESI): m/z [M + Na]+ calcd for C35H53NO6SSiNa: 666.3265;
found: 666.3271.
Yield: 3q: 47 mg (77%) and 3q: 4 mg (6%); clear oils.
tert-Butyl 3,4,6-Tri-O-benzyl-2-deoxy-2-nitro-1-thio-D-galactopy-
ranoside (3s)
3q
[]D22 +9.0 (c 2.0, CHCl3).
IR (KBr): 2938, 1601, 1387, 1159, 779, 673 cm–1
Yield: 40 mg (73%); clear oil.
.
3s
[]D21 +13.0 (c 0.5, CHCl3).
IR (KBr): 1968, 1615, 1570, 1296, 722, 618 cm–1
.
© 2019. Thieme. All rights reserved. — Synthesis 2019, 51, A–K

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Y.-L. Hu et al.
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Synthesis
1H NMR (400 MHz, CDCl3):  = 7.39–7.18 (m, 15 H), 5.87 (d, J = 6.3 Hz,
1 H), 5.27 (dd, J = 10.9, 6.3 Hz, 1 H), 4.84 (d, J = 11.1 Hz, 1 H), 4.75 (d,
J = 10.6 Hz, 1 H), 4.71 (d, J = 10.6 Hz, 1 H), 4.46 (dd, J = 11.3, 3.1 Hz, 2
H), 4.40 (dd, J = 12.5, 4.9 Hz, 2 H), 4.19 (dd, J = 10.9, 3.0 Hz, 1 H), 4.02
(d, J = 2.5 Hz, 1 H), 3.68–3.58 (m, 1 H), 3.50 (dd, J = 9.1, 5.6 Hz, 1 H),
1.32 (s, 9 H).
13C NMR (100 MHz, CDCl3):  = 137.95, 137.68, 137.17, 128.48,
128.41, 128.30, 128.21, 128.10, 128.06, 127.82, 127.74, 84.24, 79.90,
75.94, 75.24, 73.48, 73.38, 73.06, 69.84, 67.96, 44.64, 31.14.
1H NMR (400 MHz, CDCl3):  = 7.50–7.22 (m, 20 H), 5.89 (d, J = 5.9 Hz,
1 H), 5.36 (dd, J = 10.9, 5.9 Hz, 1 H), 4.88 (d, J = 11.2 Hz, 1 H), 4.84–4.75
(m, 2 H), 4.58 (t, J = 6.4 Hz, 1 H), 4.55–4.42 (m, 3 H), 4.37 (dd, J = 10.9,
2.6 Hz, 1 H), 4.09 (d, J = 2.0 Hz, 1 H), 3.67–3.56 (m, 2 H).
13C NMR (100 MHz, CDCl3):  = 137.81, 137.67, 137.03, 132.90,
132.15, 129.12, 128.55, 128.44, 128.35, 128.30, 128.21, 128.18,
128.07, 127.86, 127.85, 127.77, 85.63, 84.47, 75.83, 75.18, 73.50,
73.42, 73.18, 70.60, 68.35.
HRMS (ESI): m/z [M + Na]+ calcd for C33H33NO6SNa: 594.1921; found:
594.1917.
HRMS (ESI): m/z [M + Na]+ calcd for C31H37NO6SNa: 574.2234; found:
574.2225.
p-Tolyl 3,4,6-Tri-O-benzyl-2-deoxy-2-nitro-1-thio-D-galactopyra-
noside (3v, 3v) 14
Ethyl (2S)-3-({(3R,4R,5R,6R)-4,5-Bis(benzyloxy)-6-[(benzy-
loxy)methyl]-3-nitrotetrahydro-2H-pyran-2-yl}thio)-2-(1,3-diox-
oisoindolin-2-yl)propanoate (3t, 3t)
Yield: 3v: 46 mg (80%) and 3v: 1.8 mg (3%); white solids.
Yield: 3t: 32.5 mg (44%) and 3t: 8.5 mg (11%); clear oils.
3v
[]D24 +148 (c 1.0, CHCl3).
3t
1H NMR (400 MHz, DMSO-d6):  = 7.39–7.23 (m, 17 H), 7.06 (d, J = 8.0
Hz, 2 H), 5.96 (d, J = 5.9 Hz, 1 H), 5.24 (dd, J = 11.1, 5.9 Hz, 1 H), 4.88 (d,
J = 11.1 Hz, 1 H), 4.76 (d, J = 11.2 Hz, 1 H), 4.64 (d, J = 11.1 Hz, 1 H),
4.60–4.43 (m, 5 H), 4.34 (d, J = 2.5 Hz, 1 H), 3.65 (dd, J = 10.1, 5.1 Hz, 1
H), 3.58 (dd, J = 10.1, 7.0 Hz, 1 H), 2.25 (s, 3 H).
13C NMR (101 MHz, DMSO-d6):  = 138.27, 138.14, 138.10, 137.55,
132.98, 129.89, 128.40, 128.30, 128.25, 128.03, 127.89, 127.86,
127.67, 127.57, 84.65, 84.44, 75.15, 74.43, 73.44, 72.41, 71.65, 70.72,
68.80, 20.70.
[]D28 +44.6 (c 1.0, CHCl3).
IR (KBr): 2922, 1714, 1387, 1227, 1218, 1091, 771 cm–1
1H NMR (400 MHz, CDCl3):  = 7.88–7.81 (m, 2 H), 7.77–7.69 (m, 2 H),
7.39–7.25 (m, 13 H), 7.24–7.17 (m, 2 H), 5.83 (d, J = 5.9 Hz, 1 H), 5.26
(dd, J = 10.9, 5.9 Hz, 1 H), 4.98 (dd, J = 11.1, 5.1 Hz, 1 H), 4.81 (d, J =
11.1 Hz, 1 H), 4.64 (s, 2 H), 4.50–4.38 (m, 3 H), 4.27–4.14 (m, 4 H),
3.98 (d, J = 2.4 Hz, 1 H), 3.58–3.43 (m, 3 H), 3.36 (dd, J = 14.3, 11.2 Hz,
1 H), 1.20 (t, J = 7.1 Hz, 3 H).
.
13C NMR (100 MHz, CDCl3):  = 167.71, 167.33, 137.83, 137.68,
136.98, 134.28, 131.64, 128.48, 128.47, 128.33, 128.12, 128.10,
128.04, 127.86, 127.83, 127.76, 123.72, 83.96, 79.94, 75.78, 75.16,
73.51, 73.15, 73.04, 70.21, 67.83, 62.33, 50.32, 29.10, 14.03.
HRMS (ESI): m/z [M + Na]+ calcd for C40H40N2O10SNa: 763.2296;
found: 763.2283.
HRMS (ESI): m/z [M + Na]+ calcd for C34H35NO6SNa: 608.2077; found:
608.2072.
Cyclohexyl 3,4,6-Tri-O-benzyl-2-deoxy-2-acetamido-8--D-galac-
topyranoside (5)
Yield: 158 mg (90%); white solid; mp 211–213 °C; []D29 +11.4 (c 1.0,
CHCl3).
IR (KBr): 2953, 1646, 1554, 1039, 719, 612 cm–1
.
3t
[]D28 +16.2 (c 0.5, CHCl3).
IR (KBr): 2960, 2358, 1714, 1259, 1022, 773 cm–1
1H NMR (400 MHz, DMSO-d6):  = 7.93 (d, J = 7.8 Hz, 1 H), 7.39–7.22
(m, 15 H), 5.46 (d, J = 5.3 Hz, 1 H), 4.73 (dd, J = 11.2, 2.3 Hz, 2 H), 4.59
(d, J = 11.1 Hz, 1 H), 4.52–4.43 (m, 3 H), 4.43–4.36 (m, 1 H), 4.26 (t, J =
6.0 Hz, 1 H), 4.08 (s, 1 H), 3.67 (dd, J = 11.4, 2.5 Hz, 1 H), 3.61 (dd, J =
9.9, 5.4 Hz, 1 H), 3.55 (dd, J = 9.8, 6.9 Hz, 1 H), 2.75 (td, J = 9.7, 3.4 Hz,
1 H), 1.89 (d, J = 11.8 Hz, 2 H), 1.83 (s, 3 H), 1.67–1.57 (m, 2 H), 1.30–
1.15 (m, 6 H).
13C NMR (100 MHz, DMSO-d6):  = 169.54, 138.73, 138.54, 138.30,
128.21, 128.20, 128.16, 127.84, 127.57, 127.48, 127.43, 127.40, 82.80,
76.74, 74.01, 73.47, 72.21, 71.16, 69.89, 69.14, 49.25, 42.22, 33.66,
33.36, 25.45, 25.32, 25.21.
.
1H NMR (400 MHz, CDCl3):  = 7.91–7.85 (m, 2 H), 7.79–7.73 (m, 2 H),
7.38–7.26 (m, 13 H), 7.20 (dd, J = 7.1, 2.4 Hz, 2 H), 5.76 (d, J = 6.0 Hz, 1
H), 5.22 (dd, J = 10.9, 6.0 Hz, 1 H), 5.02 (dd, J = 11.1, 4.4 Hz, 1 H), 4.80
(d, J = 11.1 Hz, 1 H), 4.64 (s, 2 H), 4.55 (d, J = 11.8 Hz, 1 H), 4.47 (dd, J =
11.5, 4.5 Hz, 2 H), 4.43–4.38 (m, 1 H), 4.23–4.08 (m, 3 H), 4.03 (d, J =
2.3 Hz, 1 H), 3.70–3.54 (m, 3 H), 3.41 (dd, J = 14.4, 4.4 Hz, 1 H), 1.19 (t,
J = 7.1 Hz, 3 H).
13C NMR (100 MHz, CDCl3):  = 167.52, 167.50, 137.85, 137.83,
137.00, 134.32, 131.69, 128.47, 128.43, 128.34, 128.12, 128.07,
127.85, 127.81, 127.77, 123.72, 84.26, 83.73, 75.74, 75.19, 73.60,
73.11, 72.99, 70.23, 67.98, 62.32, 53.06, 31.25, 14.01.
HRMS (ESI): m/z [M + Na]+ calcd for C35H43NO5SNa: 612.2754; found:
612.2747.
HRMS (ESI): m/z [M + Na]+ calcd for C40H40N2O10SNa: 763.2296;
found: 763.2289.
Cyclohexyl 3, 4, 6-tri-O-benzyl-2-deoxy-2-nitro-1-thio-D-gluco-
pyranoside (6, 6); Cyclohexyl 3, 4, 6-tri-O-benzyl-2-deoxy-2-ni-
tro-1-thio--D-mannopyranoside (7)
Phenyl 3,4,6-Tri-O-benzyl-2-deoxy-2-nitro-1-thio-D-galactopyra-
noside (3u, 3u)
Yield: 6: 8 mg (14%), 6: 24 mg (42%) and 7: 9 mg (16%); clear oils.
Yield: 3u: 40 mg (70%) and 3u: 1 mg (2%); white solids.
6
1H NMR (400 MHz, CDCl3):  = 7.38–7.27 (m, 11 H), 7.25–7.17 (m, 4
H), 4.91–4.71 (m, 3 H), 4.68–4.45 (m, 5 H), 4.42–4.22 (m, 1 H), 3.91–
3.65 (m, 3 H), 3.64–3.56 (m, 1 H), 2.99–2.89 (m, 1 H), 1.98 (d, J = 8.2
Hz, 2 H), 1.73 (d, J = 4.9 Hz, 2 H), 1.58 (s, 1 H), 1.48–1.16 (m, 5 H).
3u
[]D24 +142 (c 1.0, CHCl3).
IR (KBr): 2920, 2360, 1542, 1458, 1357, 1056, 744 cm–1
.
© 2019. Thieme. All rights reserved. — Synthesis 2019, 51, A–K

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Y.-L. Hu et al.
Paper
Synthesis
13C NMR (100 MHz, CDCl3):  = 137.86, 137.47, 136.88, 128.48,
128.45, 128.36, 128.09, 127.99, 127.84, 127.67, 127.65, 89.64, 82.86,
81.25, 79.47, 75.53, 75.13, 73.42, 68.39, 44.12, 33.96, 33.77, 25.88,
25.75, 25.46.
HRMS (ESI): m/z [M + Na]+ calcd for C33H39NO6SNa: 600.2390; found:
600.2380.
Org. Biomol. Chem. 2008, 6, 227. (f) Bennett, E. P.; Mandel, U.;
Clausen, H.; Gerken, T. A.; Fritz, T. A.; Tabak, L. A. Glycobiology
2012, 22, 736.
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7
[]D29 +54.4 (c 1.0, CHCl3).
IR (KBr): 2953, 1646, 1554, 1039, 719, 612 cm–1
.
1H NMR (400 MHz, CDCl3):  = 7.38–7.26 (m, 13 H), 7.18 (dd, J = 7.2,
2.0 Hz, 2 H), 5.77 (s, 1 H), 5.00 (dd, J = 4.9, 1.2 Hz, 1 H), 4.80 (d, J = 10.9
Hz, 1 H), 4.75–4.62 (m, 3 H), 4.50 (dd, J = 11.4, 7.6 Hz, 2 H), 4.38–4.29
(m, 1 H), 4.28–4.18 (m, 1 H), 4.06 (dd, J = 8.6, 4.9 Hz, 1 H), 3.81 (dd, J =
11.0, 5.0 Hz, 1 H), 3.70 (dd, J = 10.9, 1.8 Hz, 1 H), 2.93–2.79 (m, 1 H),
1.96 (dd, J = 28.4, 13.4 Hz, 2 H), 1.69 (d, J = 10.8 Hz, 2 H), 1.56 (s, 1 H),
1.47–1.14 (m, 5 H).
(5) (a) Wilson, J. C.; Kiefel, M. J.; Angus, D. I.; von Itzstein, M. Org.
Lett. 1999, 1, 443. (b) Witczak, Z. J.; Culhane, J. M. Microbiol. Bio-
technol. 2005, 69, 237.
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Crich, D. Org. Lett. 2012, 14, 4138. (c) Zeng, X.; Smith, R.; Zhu, X.
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K.; Li, B.-Y.; Liang, C.-F.; Hung, J.-T.; Chiou, S.-P.; Yu, A. L.; Hwu, J.
R.; Lin, C. C. Chem. Eur. J. 2017, 23, 6876.
13C NMR (100 MHz, CDCl3):  = 138.11, 137.92, 136.84, 128.59,
128.38, 128.30, 128.23, 128.16, 127.97, 127.81, 127.64, 127.54, 86.98,
79.49, 77.37, 75.11, 74.06, 73.29, 73.03, 72.03, 68.74, 44.52, 33.52,
33.40, 25.90, 25.71, 25.52, 22.63.
HRMS (ESI): m/z [M + Na]+ calcd for C33H39NO6SNa: 600.2390; found:
600.2386.
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Wong, C.-H. Angew. Chem. Int. Ed. 2005, 44, 4596.
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137, 65. (b) Nitz, M.; Bundle, D. R. J. Org. Chem. 2001, 66, 8411.
(c) Eisele, T.; Toepfer, A.; Kretzschmar, G.; Schmidt, R. R. Tetra-
hedron Lett. 1996, 37, 1389.
Funding Information
We thank the National Natural Science Foundation of China (NSFC-
21672170), the Natural Science Foundation of Shaanxi Province
(2018JC-020, 2018JM2029), the China Postdoctoral Science Founda-
tion (2018M643705), the Key Science and Technology Innovation
Team of Shanxi Province (2017KCT-37), and the ‘Top-rated Discipline’
Construction Scheme of Shaanxi Higher Education for financial sup-
port.
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(9) (a) Lonn, H. Carbohydr. Res. 1985, 139, 105. (b) Yan, L.; Kahne, D.
J. Am. Chem. Soc. 1996, 118, 9239. (c) Fuchss, T.; Schmidt, R. R.
Synthesis 1998, 753. (d) Auzanneau, F.-I.; Bennis, K.; Fanton, E.;
Promé, D.; Defaye, J.; Gelas, J. J. Chem. Soc., Perkin Trans. 1 1998,
3629. (e) Xu, Y.; Zhang, Q.; Xiao, Y.; Wu, P.; Chen, W.; Song, Z.;
Xiao, X.; Meng, L.; Zeng, J.; Wan, Q. Tetrahedron Lett. 2017, 58,
2381. (f) Kumar, A.; Schmidt, R. R. Eur. J. Org. Chem. 2012, 2715.
(g) De Leon, C. A.; Lang, G.; Saavedra, M. I.; Pratt, M. R. Org. Lett.
2018, 20, 5032.
(10) Eszenyi, D.; Kelemen, V.; Balogh, F.; Bege, M.; Csávás, M.;
Herczegh, P.; Borbás, A. Chem. Eur. J. 2018, 24, 4532.
(11) (a) Schmidt, R. R.; Vankar, Y. D. Acc. Chem. Res. 2008, 41, 1059.
(b) Delaunay, T.; Poisson, T.; Jubault, P.; Pannecoucke, X. Eur. J.
Org. Chem. 2014, 7525.
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1988, 18, 97.
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(14) Peng, P.; Geng, Y.; Göttker-Schnetmann, I.; Schmidt, R. R. Org.
Lett. 2015, 17, 1421.
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37, 2691. (c) Biju, A. T.; Kuhl, N.; Glorius, F. Acc. Chem. Res. 2011,
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Supporting Information
Supporting information for this article is available online at
https://doi.org/10.1055/s-0039-1690099.
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