FeCl3/C as an efficient catalyst for Ferrier rearrangement of 3,4,6-tri-O-Benzyl-D-glucal

Article abstract of DOI:10.1080/07328303.2020.1788575

FeCl₃/C was used as an efficient and convenient promoter for glycosylation through Ferrier-type rearrangement of 3,4,6-tri-O-benzyl-D-glucal, which is a relatively unreactive substrate for this type of reaction. The method was applicable to a w

Full text of DOI:10.1080/07328303.2020.1788575

Journal of Carbohydrate Chemistry
ISSN: (Print) (Online) Journal homepage: https://www.tandfonline.com/loi/lcar20
FeCl3/C as an efficient catalyst for Ferrier
rearrangement of 3,4,6-tri-O-Benzyl-D-glucal
Yuling Mei , Youxian Dong , Juan Li , Bo Zhang , Guosheng Sun , Jiafen Zhou ,
Wenshuai Si , Yiwen Han , Zhenliang Wu & Jianbo Zhang
To cite this article: Yuling Mei , Youxian Dong , Juan Li , Bo Zhang , Guosheng Sun , Jiafen
Zhou , Wenshuai Si , Yiwen Han , Zhenliang Wu & Jianbo Zhang (2020): FeCl3/C as an efficient
catalyst for Ferrier rearrangement of 3,4,6-tri-O-Benzyl-D-glucal, Journal of Carbohydrate
Chemistry, DOI: 10.1080/07328303.2020.1788575
To link to this article: https://doi.org/10.1080/07328303.2020.1788575
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JOURNAL OF CARBOHYDRATE CHEMISTRY
https://doi.org/10.1080/07328303.2020.1788575
FeCl3/C as an efficient catalyst for Ferrier
rearrangement of 3,4,6-tri-O-Benzyl-D-glucal
Yuling Mei, Youxian Dong, Juan Li, Bo Zhang, Guosheng Sun, Jiafen Zhou,
Wenshuai Si, Yiwen Han, Zhenliang Wu, and Jianbo Zhang
School of Chemistry and Molecular Engineering, East China Normal University, Shanghai, China
ABSTRACT
ARTICLE HISTORY
Received 6 May 2020
Accepted 24 June 2020
FeCl3/C was used as an efficient and convenient promoter for
glycosylation through Ferrier-type rearrangement of 3,4,6-tri-
O-benzyl-D-glucal, which is a relatively unreactive substrate for
this type of reaction. The method was applicable to a wide
range of alcohols, especially phenols. A series of 2,3-unsatur-
ated-O-glucosides were prepared efficiently (47–92%) by this
method under mild conditions.
KEYWORDS
FeCl3/C; Ferrier
rearrangement; promoter;
glycosylation; 346-tri-O-
benzyl-D-glucal
Introduction
2,3-Unsaturated-O-glycosides are of great importance in organic synthesis
and have been widely used as chiral intermediates in the preparation of
various biologically active compounds,[1] such as nucleosides,[2] antibiot-
ics,[3] glycopeptides,[4,5] oligosaccharides,[6] uronic acids,[7] and modified
sugar derivatives.[8] The C2-C3 double bond of the pyranose ring can be
further modified via several types of reactions, such as hydroxylation,
hydrogenation, oxidation and aminohydroxylation, to generate structural
complexity and diversity.[9–15] One of the most valuable methods to achieve
2,3-unsaturated-O-glycosides directly and efficiently is Ferrier rearrange-
ment, in which glycal is reacted with nucleophiles under the promotion of
various catalysts.[16] So far, many reagents have been developed to catalyze
[22–24]
this reaction,[17–21] including Bronsted acid,
Lewis acid,[25–28] oxi-
€
dant,[29] etc. However, most catalysts are difficult to be applied to the
rearrangement of 3,4,6-tri-O-benzyl-D-glycal, mainly owing to the lower
reactivity of O-benzyl sugar comparing to O-acetyl sugars in this reac-
tion.[22] Previous methods reported for synthesis of 2,3-unsaturated glyco-
sides from 3,4,6-tri-O-benzyl-D-glycal are shown in Figure 1. For instance,
in 2001, Pachamuth and coworkers reported CAN-catalyzed synthesis of
2-deoxyglycosides. Meanwhile, 2,3-unsaturated glycoside product was also
CONTACT Jianbo Zhang
jbzhang@chem.ecnu.edu.cn
School of Chemistry and Molecular Engineering,
East China Normal University, No 500, Dongchuan Road, Shanghai 200241, P. R. China
ß 2020 East China Normal University

2
Y. MEI ET AL.
Figure 1. Methods for the synthesis of 2,3-unsaturated glycosides from 3,4,6-tri-O-benzyl-
D-glycal.
obtained in low yields (18–44%).[30] Another approach was reported by the
Lin group, using 10 equiv of TFA to catalyze the reaction of 3,4,6-tri-O-
benzyl-D-galactal with cyclohexanol and the Ferrier rearrangment product
was obtained in a yield of 24%.[31] Subsequently, Rauter and coworkers
developed acid zeolite catalysts to prepare 2,3-unsaturated O- and S-glyco-
sides at 85 ꢀC with good a-selectivity, despite that only three acceptors
were suitable to low yields (38–50%).[32] In 2008, Fe2(SO4)3ꢁvH2O (1 mol%)
was used as a catalyst to synthesize a benzyl protected 2,3-unsaturated
glycoside by the Zhang group. The reaction was carried out at 60 ꢀC or
under microwave irradiation to give good yields (70–84%). Unfortunately,
only four alcohol acceptors were suitable for this catalytic system.[33]
Recently, our group used H2SO4/SiO2 as a catalyst to promote the reaction
of benzyl-protected glycal with a series of alcohol acceptors at room tem-
perature. The reaction conditions were mild and the yields were good, but
it was necessary to add nucleophilic acceptors after rearrangement.[24]
More recently, Chen and co-workers developed Gd(OTf)3 as a Lewis acid
to catalyze the synthesis of benzyl protected 2,3-unsaturated glycosides at
60 ꢀC.[26] Through the above reports, we can conclude that the current
methods suffered from disadvantages including narrow scope of acceptors
(none of the reaction systems are suitable for phenolic acceptors), low
yields, long reaction time, harsh reaction conditions, or use of toxic agents.
Iron catalysts have been extensively utilized as convenient and eco-
friendly catalysts in synthetic chemistry.[34–37] It is noteworthy that FeCl3
as a catalyst plays a more and more important role in carbohydrate

JOURNAL OF CARBOHYDRATE CHEMISTRY
3
chemistry.[38–41] Based on our long-standing interest in iron catalysts, we
have reported a series of glycosylation reactions catalyzed by ferric chlor-
ide.[42–44] Indeed, some of this type of catalysts such as FeCl3,[45]
[46]
Fe2(SO4)3ꢂxH2O,[33] Fe(OTf)3
and FeCl3 immobilized in ionic liquids[47]
have been utilized for the Ferrier rearrangement. In our previous reports,
FeCl3ꢂ6H2O/C, Fe3O4@C@SO3H and Fe3O4@C@Fe(III) were successfully
used as the catalysts for 3,4,6-tri-O-acetyl-D-glucal Ferrier rearrangement
with high yields and anomeric selectivity.[48–50] Recently, our group has
successfully applied FeCl3/C to catalyze b-stereoselective glycosylation of
alcohols and phenolic acceptors for the synthesis of benzyl protecting prop-
argyl glycosides.[51] In view that immobilized iron (III) catalysts have been
successfully used in glycosylation, we expected that this mild approach
would find more applications in glycoside synthesis, especially in Ferrier
rearrangement of ether-protected glycals. This report describes the Ferrier
rearrangement of 3,4,6-tri-O-benzyl-D-glucal under mild conditions using
FeCl3/C as an efficient catalyst.
Results and discussion
Initially, we conducted a model reaction between 3,4,6-tri-O-benzyl-D-glu-
cal 1 and n-octanol 2a in the presence of different iron catalysts in DCM
at room temperature. The main reason for choosing n-octanol, instead of
benzyl alcohol, as the model nucleophilic acceptor was due to the presence
of the benzyl protecting group at the 3-O-position, which can easily form
rearrangement by-products of 3,4,6-tri-O-benzyl-D-glucal.[24] First, we
examined a series of iron (III) catalysts, FeCl3, FeCl3ꢁ6H2O/C, FeBr3, FeF3,
Fe2(SO4)3 and Fe(acac)3, for their ability to promote the glycosylation in
CH2Cl2 at rt. As shown in Table 1, FeCl3 showed the best catalytic activity
(Entries 1–6). However, the glycosylation yield was not particularly high
(ꢃ67%). As a continuous work, we tried to substitute FeCl3 for immobi-
lized iron (III) catalysts. Then, reaction optimization was carried out by
screening different carriers, including SiO2, Al2O3, molecular sieves and
carbon, to immobilize FeCl3 according to the literature methods.[51–53] To
our delight, we found that FeCl3/C was the most promising, because other
immobilized iron (III) catalysts, including FeCl3/SiO2, FeCl3/Al2O3 and
FeCl3/4 Å MS, could only give the desired product either in longer time or
poorer yields (Table 1, Entries 7–10). We also tried FeCl3ꢂ6H2O/C,[48]
which had been utilized for Ferrier rearrangement of 3,4,6-tri-O-acetyl-D-
glucal. Unfortunately, we did not get the desired result (Table 1, Entry 11).
Then, the optimal mass ratio of FeCl3/C was evaluated. When changing the
mass ratio of FeCl3/C to 3:5 or 1:10, product was obtained with lower
yields (Entries 12 and 13). At the same time, to eliminate the possible

4
Y. MEI ET AL.
Table 1. Catalyst screening for the glycosylation of alcohol 2a with glucal 1a
.
Mass ratio
(Cat./C)
Eq.
(Cat.)
Time
(h)
Yield
(%)a
Entry
Catalyst
FeCl3
1
2
3
4
5
6
7
8
–
–
–
–
–
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.05
0.2
0.1
0.1
0.1
2
2
2
6
6
6
2
2
20
3
4
3
4
3
3
5
2
5
67
57
FeCl3ꢂ6H2O
FeBr3
47
FeF3
NDb
NDb
NDb
78
Fe2(SO4)3
Fe(acac)3
FeCl3/SiO2
FeCl3/Al2O3
FeCl3/4Å MS
FeCl3/C
–
1:5
1:5
1:5
1:5
1:5
3:5
1:10
1:5
1:5
1:5
1:5
1:5
1:5
1:5
80
9
NDb
88
10
11
12
13
14c
15d
16
17
18e
19f
20g
FeCl3ꢂ6H2O/C
69
76
72
78
89
80
83
FeCl3/C
FeCl3/C
FeCl3/C
FeCl3/C
FeCl3/C
FeCl3/C
FeCl3/C
FeCl3/C
FeCl3/C
78
24
24
NDb
65
aIsolated yields. bNot determined. cThree equivalents of 2a were used. dFive equivalents of 2a were used. e2a
was added after the rearrangement occurred. fEt2O was used as solvent. gCH3CN was used as solv-
ent, a:b ¼ 7:1.
Ferrier rearrangement and other side reactions with benzyl alcohol gener-
ated in situ, more than one equivalent of the alcohol was tested, and we
found that 4 equivalents of the alcohol were sufficient for this purpose
(Entries 14–15). Moreover, we further optimized the use of FeCl3/C, and
found that reducing the amount of catalyst to 0.05 equivalent, the yield
reduced to 80% and the reaction time was increased to 5 h (Entry 16).
Increasing the catalyst equivalent to 0.2, the reaction time was shortened,
but the yield was reduced to 83% (Entry 17). We also tested the two-step
glycosylation as depicted in the reference.[24] After the system undergoing
rearrangement reaction and then adding the acceptor, the reaction time
required was longer while the yield was reduced (78%) with the generation
of more rearranged by-products (Entry 18). Solvent effect was also eval-
uated, and we found that the reaction did not proceed in Et2O (Entry
19).[50] When using CH3CN as the solvent, desired product was obtained
in poor yield (Entry 20),[28,50] although the a/b selectivity of product was
slightly increased to 7:1. Considering the balance of reaction time and
yields, we deemed DCM as the best solvent. Therefore, we have established
the optimal reaction conditions as 1.0 equivalent of donor, 4.0 equivalents

JOURNAL OF CARBOHYDRATE CHEMISTRY
5
Table 2. The Scope of Ferrier-rearrangement based glycosylation of various alcohols and
phenols with glucal 1 under optimal conditionsa.
of acceptor, and 0.1 equivalent of FeCl3/C (1:5) in DCM under room
temperature.
Having established the optimal reaction conditions, we then turned our
attention to exploring the scope of the acceptors using compounds 2a–2u
as shown in Table 2. In all cases, reactions proceeded smoothly and 2,3-
unsaturated glycosides were obtained in good to excellent yields (47–92%),

6
Y. MEI ET AL.
demonstrating that the catalytic system tolerated the presence of alcoholic,
saccharide, and phenolic nucleophiles, which was a significantly extended
range of applicable nucleophilic acceptors compared to that reported in the
literature. Structures of all compounds were confirmed by NMR and mass
spectrometry, in accordance with literature reports.[30–33] In specific, the
reactions with linear alcohols afforded products 3a–3f in good to excellent
yields (74–91%). When a branched alcohol was used as the nucleophile, the
product 3g was also obtained in 83% yield. Additionally, the reaction of
chlorohydrin with 3,4,6-tri-O-benzyl-D-glucal afforded 3h in a slightly
lower yield (81%), probably due to the presence of an electron withdrawing
group in the acceptor. For secondary alcohols such as cyclohexanol and
menthol, the reaction system was also suitable to give 3i and 3j.
Glycosylation with sterol also proceeded smoothly to afford 3k and 3l.
Moreover, the catalytic system was suitable for saccharide acceptors. For
example, the reactions with glucoside acceptor 2m, mannoside 2n and
rhamnoside acceptor 2o afforded the desired products 3m–3o in good
yields (63–71%) and high a-selectivity. It is worth noting that when galac-
toside acceptor 2p was used to react with the donor under optimal condi-
tions, the conversion rate of the donor was only 5% in 12 h, and after
increasing the catalyst to 1 equivalent, the reaction could be completed
in 3.5 h.
After the successful synthesis of various alcohol glycosides by the above
method, we hoped to extend it to phenolic acceptors, considering the bio-
logical significance of many phenolic deoxyglycosides.[43,54–57] Although it
is more difficult for phenols react with glycals as compared to alcohols,
especially when FeCl3 was utilized as the catalyst,[33,45] it should be noted
that our method succeeded with phenols when 0.3 equivalent of FeCl3/C
(mass ratio of FeCl3/C ¼ 1:7) was used. As a result, a series of phenolic gly-
cosides 3q–3u were conveniently obtained in good yields (47–80%) and
high anomeric selectivity (a:b > 6:1) in short reaction time (0.7–1.5 h).
In order to gain an insight into the reaction mechanism, we carried out
the following control experiments (Fig. 2). Firstly, when 0.1 equivalent of
DMAP was added in the system, the glycosylation reaction was quenched
and no product was formed, leading to recovery of starting materials.
However, addition of 0.1 equivalent of Cs2CO3 to the system, the reaction
still occurred. Based on the above experimental results, we believed that
Figure 2. Two-step glycosylation of 2a with 1 involving 1a as an intermediate.

JOURNAL OF CARBOHYDRATE CHEMISTRY
7
Figure 3. A plausible mechanism for Ferrier-rearrangement based glycosylation reactions of
glucal 1.
this was a Lewis acid-catalyzed process rather than a protic one. Secondly,
when 1 was treated with the catalyst under the optimized reaction without
adding a nucleophilic acceptor, 1a was obtained after column chromatog-
1
raphy and its structure was confirmed by H-NMR data. Furthermore, after
the isolated product 1a was dissolved in dry DCM, treated with FeCl3/C
for 5 min and then mixed with acceptor 2a, the desired product 3a was
formed in 78% isolated yield upon stirring at rt for 3 h. This result implied
that rearrangement product 1a was possibly an intermediate and could be
further converted into product 3a in the presence of nucleophiles under
the optimized reaction conditions.
Based on the above observation and previous reports,[16,23,24,31,43] we
proposed a reaction mechanism as depicted in Figure 3. First, 3,4,6-tri-
O-benzyl-D-glucal was converted into an oxonium ion intermediate with
the assistance of FeCl3/C. Thereafter, this intermediate was transformed
into glycosylation products via reaction with nucleophilic acceptors. At
the same time, in the absence of proper nucleophiles the intermediate
would also undergo rearrangement to result in 2,3-unsaturated benzyl
glycoside 1a as a by-product. However, the rearranged by-product 1a
could be further converted to an oxonium ion intermediate with the
help of iron catalyst to react with nucleophiles to afford the
desired products.
In conclusion, we have described herein a facile and efficient method for
the synthesis of 2,3-unsaturated-O-glycosides from 3,4,6-tri-O-benzyl-D-gly-
cal catalyzed by FeCl3/C. The reaction is applicable to a wide range of
acceptors including primary and secondary alcohols, sterols, sugars ad phe-
nols, and the conditions are mild. The reaction proceeds with good to
excellent yields. In addition, the catalyst FeCl3/C has many advantages such
as being affordable and safe, stable in the air, mild and efficient perform-
ance. Thus, we expect that this methodology will find widespread use in
glycoside and oligosaccharide synthesis. Further applications of this

8
Y. MEI ET AL.
methodology to other ether-protected glycals are currently explored in
our laboratory.
Experimental section
General procedures
To a stirred solution of 3, 4, 6-tri-O-benzyl-D-glucal (42 mg, 0.1 mmol) in
DCM (1 mL) were added the corresponding acceptors (4 equiv.) and FeCl3/
C[44] (0.1 equiv.) at ambient temperature. After the reaction was completed
(monitored by TLC), the reaction mixture was filtered and the catalyst was
washed with dichloromethane. After evaporation of the solvent under vac-
uum, the crude products were purified by silica gel column chromatog-
raphy. (Petroleum ether/EtOAc ¼ 10/1). All compounds were fully
characterized by NMR and MS.
Catalyst FeCl3/C
Activated charcoal-supported FeCl3 was prepared by the following method:
To a mixture of FeCl3 (0.1 g) and activated charcoal (0.5 g, 200–300 mesh)
was added anhyd EtOH (5 mL) and the slurry was refluxed for 30 min.[51]
The solvent was evaporated under reduced pressure resulting in free flow-
ing FeCl3/activated charcoal, which was dried at 120 ꢀC for 2 h and used
for the reactions directly.
Product characterization data
Octyl 4, 6-di-O-benzyl-2, 3-dideoxy-D-erythro-hex-2-enopyranoside
1
(3a)[24]: a:b 5 4:1 H NMR (500 MHz, CDCl3): a-Anomer: d ¼ 7.35 ꢄ 7.23
(m, 10H), 6.06 (d, J ¼ 10.3 Hz, 1H), 5.78 (d, J ¼ 10.3 Hz, 1H), 5.01(s, 1H),
4.65 (d, J ¼ 12.2 Hz, 1H), 4.60 (d, J ¼ 11.5 Hz, 1H), 4.51 (d, J ¼ 12.2 Hz,
1H), 4.44 (d, J ¼ 11.5 Hz, 1H), 4.17 (d, J ¼ 9.4 Hz, 1H), 3.97 (d, J ¼ 9.4 Hz,
1H), 3.80–3.70 (m, 3H), 3.50–3.46 (m, 1H), 1.62–1.56 (m, 2H), 1.26 (br,
10H), 0.89–0.86 (m, 3H). b-Anomer: d ¼ 7.35–7.23 (m, 10H), 6.03 (d,
J ¼ 12.5 Hz, 1H), 5.83 (d, J ¼ 12.5 Hz, 1H), 5.11 (s, 1H), 4.59 (d, J ¼ 12.2 Hz,
1H), 4.57 (d, J ¼ 6.8 Hz, 1H), 4.52 (d, J ¼ 6.8 Hz, 1H), 4.43 (d, J ¼ 12.5 Hz,
1H), 4.17 (d, J ¼ 2.0 Hz, 1H), 3.97 (d, J ¼ 2.0 Hz, 1H), 3.97–3.95 (m, 3H),
3.50–3.46 (m, 1H), 1.62–1.56 (m, 2H), 1.26 (br, 10H), 0.89–0.86 (m, 3H).
ESI-MS [M þ Na]þ: calcd for C28H38NaO4: 461.28, found: 461.33.
Methyl 4, 6-di-O-benzyl-2, 3-dideoxy-D-erythro-hex-2-enopyranoside
1
(3 b):[24]a:b 5 5:1 H NMR (500 MHz, CDCl3): a-Anomer: d ¼ 7.35 ꢄ 7.23
(m, 10H), 6.07 (d, J ¼ 10.3 Hz, 1H), 5.77 (dt, J ¼ 10.3, 2.1 Hz, 1H), 4.91 (s,
1H), 4.65 (d, J ¼ 12.2 Hz, 1H), 4.59 (d, J ¼ 11.6 Hz, 1H), 4.52 (d,

JOURNAL OF CARBOHYDRATE CHEMISTRY
9
J ¼ 12.2 Hz, 1H), 4.44 (d, J ¼ 11.6 Hz, 1H), 4.17 (dd, J ¼ 8.1 Hz, 1.4 Hz, 1H),
3.93 (dt, J ¼ 9.4 Hz, 3.2 Hz, 1H), 3.74–3.69 (m, 2H), 3.44 (d, J ¼ 13.3 Hz,
3H). b-Anomer: d ¼ 7.35 ꢄ 7.23 (m, 10H), 6.03 (d, J ¼ 12.3 Hz, 1H), 5.78
(d, J ¼ 12.3 Hz, 1H), 5.03(s, 1H), 4.65–4.44 (m, 4H), 3.98–3.94 (m, 2H),
3.74–3.69 (m, 2H), 3.44 (s, 3H). ESI-MS [M þ Na]þ: calcd for C21H24NaO4:
363.17, found: 363.17.
n-Butyl 4,6-Di-O-benzyl-2,3-dideoxy-a-D-erythro-hex-2-enopyranoside
1
(3c)[24]: a:b 5 6:1 H NMR (500 MHz, CDCl3): a-Anomer: d ¼ 7.35 ꢄ 7.24
(m, 10H), 6.07 (d, J ¼ 10.2 Hz, 1H), 5.77 (d, J ¼ 10.2, 1H), 5.01 (s, 1H), 4.65
(d, J ¼ 12.1 Hz, 1H), 4.60 (d, J ¼ 11.6 Hz, 1H), 4.51 (d, J ¼ 12.1 Hz, 1H),
4.44 (d, J ¼ 1.5 Hz, 1H), 4.17 (d, J ¼ 9.4 Hz, 1H), 3.97 (d, J ¼ 7.5 Hz, 1H),
3.85 ꢄ 3.70 (m, 3H), 3.51 ꢄ 3.47 (m, 1H), 1.60 ꢄ 1.56 (m, 2H), 1.40 ꢄ 1.35
(m, 2H), 0.93 ꢄ 0.89 (m, 3H). b-Anomer: d ¼ 7.35 ꢄ 7.24 (m, 10H), 6.02 (d,
J ¼ 12.2 Hz, 1H), 5.83 (d, J ¼ 12.2 Hz, 1H), 5.10 (s, 1H), 4.65 ꢄ 4.30 (m,
4H), 3.96 (d, J ¼ 2.0 Hz, 1H), 3.87 ꢄ 3.85 (m, 1H), 3.83 ꢄ 3.70 (m, 3H),
3.51 ꢄ 3.47 (m, 1H), 1.60 ꢄ 1.56 (m, 2H), 1.40 ꢄ 1.35 (m, 2H), 0.93–0.89
(m, 3H). ESI-MS [M þ Na]þ: calcd for C24H30NaO4: 405.21, found: 405.33.
Nonyl 4, 6-di-O-benzyl-2, 3-dideoxy-D-erythro-hex-2-enopyranoside
1
(3d):[24] a:b 5 6:1 H NMR (500 MHz, CDCl3): a-Anomer: d ¼ 7.35 ꢄ 7.23
(m, 10H), 6.06 (d, J ¼ 10.3 Hz, 1H), 5.76 (d, J ¼ 10.3 Hz, 1H), 5.01(s, 1H),
4.65 (d, J ¼ 12.2 Hz, 1H), 4.59 (d, ¼ 11.6 Hz, 1H), 4.51 (d, J ¼ 12.2 Hz, 1H),
4.43 (d, J ¼ 11.5 Hz, 1H), 4.17 (d, J ¼ 9.4 Hz, 1H), 3.97 (d, J ¼ 7.3 Hz, 1H),
3.80 ꢄ 3.68 (m, 3H), 3.50 ꢄ 3.46 (m, 1H), 1.60 ꢄ 1.55(m, 2H), 1.25 (br,
12H), 0.89 ꢄ 0.86 (m, 3H). b-Anomer: d ¼ 7.35 ꢄ 7.23 (m, 10H), 6.03 (d,
J ¼ 12.3 Hz, 1H), 5.80 (d, J ¼ 12.3 Hz, 1H), 5.10(s, 1H), 4.65 ꢄ 4.43 (m, 4H),
3.97 (d, J ¼ 7.6 Hz, 1H), 3.80 ꢄ 3.69 (m, 3H), 3.50–3.45 (m, 1H), 1.59 ꢄ 1.55
(m, 2H), 1.25 (br, 12H), 0.89 ꢄ 0.86 (m, 3H). ESI-MS: [M þ Na]þ: calcd for
C29H40NaO4:475.29, found: 475.42.
Decyl 4, 6-di-O-benzyl-2, 3-dideoxy-D-erythro-hex-2-enopyranoside
1
(3e):[24] a:b 5 6:1 H NMR (500 MHz, CDCl3): a-Anomer: d ¼ 7.35 ꢄ 7.23
(m, 10H), 6.06 (d, J ¼ 10.3 Hz, 1H), 5.78 (d, J ¼ 10.3 Hz, 1H), 5.01(s, 1H),
4.65 (d, J ¼ 12.2 Hz, 1H), 4.59 (d, J ¼ 11.6 Hz, 1H), 4.51 (d, J ¼ 12.2 Hz,
1H), 4.43 (d, J ¼ 11.5 Hz, 1H), 4.17 (d, J ¼ 9.4 Hz, 1H), 3.97 (d, J ¼ 7.6 Hz,
1H), 3.80 ꢄ 3.69 (m, 3H), 3.50 ꢄ 3.45 (m, 1H), 1.59 ꢄ 1.55 (m, 2H),
1.30 ꢄ 1.25 (m, 14H), 0.89 ꢄ 0.86 (m, 3H) b-Anomer: d ¼ 7.35 ꢄ 7.23 (m,
10H), 6.02 (d, J ¼ 12.3 Hz, 1H), 5.84 (d, J ¼ 12.3 Hz, 1H), 5.10 (s, 1H),
4.65 ꢄ 4.43 (m, 4H), 3.97 (d, J ¼ 7.6 Hz, 1H), 3.80 ꢄ 3.69 (m, 3H),
3.50 ꢄ 3.45 (m, 1H), 1.59 ꢄ 1.55 (m, 2H), 1.30 ꢄ 1.25 (m, 14H), 0.89 ꢄ 0.86
(m, 3H) ESI-MS: [M þ Na]þ calcd for C30H42NaO4:489.31, found: 489.42.
Dodecanol 4, 6-di-O-benzyl-2, 3-dideoxy-D-erythro-hex-2-enopyrano-
side (3f):[24] a:b 5 6:1 1H NMR (500 MHz, CDCl3): a-Anomer:
d ¼ 7.35–7.23 (m, 10H), 6.06 (d, J ¼ 10.3 Hz, 1H), 5.77 (d, J ¼ 10.3, 1H),

10
Y. MEI ET AL.
5.01(s, 1H), 4.65 (d, J ¼ 12.2 Hz, 1H), 4.60 (d, J ¼ 11.5 Hz, 1H), 4.51 (d,
J ¼ 12.2 Hz, 1H), 4.44 (d, J ¼ 11.5 Hz, 1H), 4.17 (d, J ¼ 9.4 Hz, 1H),
3.97 ꢄ 3.95 (m, 1H), 3.78 ꢄ 3.69 (m, 3H), 3.49 ꢄ 3.47 (m, 1H), 1.33 ꢄ 1.25
(m, 22H), 0.89 ꢄ 0.86 (m, 3H). b-Anomer: d ¼ 7.33–7.23 (m, 10H), 6.02 (d,
J ¼ 12.4 Hz, 1H), 5.81 (d, J ¼ 12.4 Hz, 1H), 5.01 (s, 1H), 4.57 ꢄ 4.49 (m 4H),
3.97 ꢄ 3.95 (m, 1H), 3.87 ꢄ 3.83 (m, 1H), 3.78 ꢄ 3.69 (m, 3H), 3.49 ꢄ 3.47
(m, 1H), 1.33 ꢄ 1.25 (m, 22H), 0.89 ꢄ 0.86 (m, 3H) 13C NMR (125 MHz,
CDCl3): d (ppm): 138.21, 138.08, 130.45, 128.37, 128.32, 128.27, 127.91,
127.78, 127.68, 127.64, 127.53, 126.74, 94.55, 73.32, 70.99, 70.38, 69.09,
68.91, 68.65, 31.89, 29.78, 29.64, 29.60, 29.58, 29.40, 29.32, 26.19, 22.66,
14.09. ESI-MS: [M þ Na]þ calcd for C32H46NaO4: 517.34, found: 517.42.
Isooctyl 4, 6-di-O-benzyl-2, 3-dideoxy-D-erythro-hex-2-enopyranoside
1
(3g):[24] a:b 5 6:1 H NMR (500 MHz, CDCl3): a-Anomer: d ¼ 7.36 ꢄ 7.24
(m, 10H), 6.06 (d, J ¼ 10.0 Hz, 1H), 5.77 (d, J ¼ 10.0 Hz, 1H), 4.99 (s, 1H),
4.67 (d, J ¼ 12.0 Hz, 1H), 4.60 (d, J ¼ 11.5 Hz, 1H), 4.51 (d, J ¼ 12.0 Hz,
1H), 4.44 (d, J ¼ 11.5 Hz, 1H), 4.18 (d, J ¼ 9.5 Hz, 1H), 3.95 (d, J ¼ 9.0 Hz,
1H), 3.77 ꢄ 3.69 (m, 3H), 3.38 ꢄ 3.34 (m, 1H),1.61 ꢄ 1.51(m, 1H),
1.36 ꢄ 1.27 (m, 8H), 0.89 ꢄ 0.84 (m, 6H). b-Anomer: d ¼ 7.36 ꢄ 7 .24 (m,
10H), 6.02 (d, J ¼ 12.0 Hz, 1H), 5.82 (d, J ¼ 12.0 Hz, 1H), 5.09 (s, 1H),
4.68 ꢄ 4.43 (m, 4H), 3.98 ꢄ 3.97 (m, 1H), 3.78 ꢄ 3.70 (m, 2H), 3.38 ꢄ 3.34
(m, 1H), 1.61 ꢄ 1.51(m, 1H), 1.36 ꢄ 1.27 (m, 8H), 0.89 ꢄ 0.84 (m, 6H). ESI-
MS: [M þ Na]þ calcd for C28H38NaO4: 461.28, found: 461.25.
Chloroethanyl 4, 6-di-O-benzyl-2, 3-dideoxy-a, b-D-erythro-hex-2-eno-
1
pyranoside (3h):[24] a:b 5 6:1 H NMR (500 MHz, CDCl3): a-Anomer:
d ¼ 7.37 ꢄ 7.23 (m, 10H), 6.10 (d, J ¼ 10.3 Hz, 1H), 5.78 (dd, J ¼ 10.3 Hz,
J ¼ 2.0 Hz, 1H), 5.07 (s, 1H), 4.65 (d, J ¼ 12.2 Hz, 1H), 4.60 (d, J ¼ 11.5 Hz,
1H), 4.50 (d, J ¼ 12.1 Hz, 1H), 4.44 (d, J ¼ 11.5 Hz, 1H), 4.17 (d, J ¼ 9.5 Hz,
1H), 4.02 ꢄ 3.98(m, 2H), 3.82 ꢄ 3.77 (m, 1H), 3.75 ꢄ 3.64 (m, 3H).
b-Anomer: d ¼ 7.37–7.23 (m, 10H), 6.06 (d, J ¼ 12.3 Hz, 1H), 5.82 (dd,
J ¼ 12.3 Hz, 1H), 5.19 (s, 1H), 4.65 ꢄ 4.42 (m, 4H), 4.01 ꢄ 3.98 (m, 2H),
3.82 ꢄ 3.78 (m, 1H), 3.75 ꢄ 3.64 (m, 3H). ESI-MS: [M þ Na]þ calcd for
C22H25ClNaO4: 411.14, found: 411.25.
Cyclohexyl 4, 6-di-O-benzyl-2, 3-dideoxy-D-erythro-hex-2-enopyrano-
1
side (3i):[24] a:b > 19:1 H NMR (500 MHz, CDCl3): d ¼ 7.33 ꢄ 7.23 (m,
10H), 6.06 (d, J ¼ 12.8 Hz, 1H), 5.73 ꢄ 5.77 (m, 1H), 5.16 (s, 1H), 4.66 (d,
J ¼ 14.9 Hz, 1H), 4.60 (d, J ¼ 14.6 Hz, 1H), 4.50 (d, J ¼ 15.3 Hz, 1H), 4.44
(d, J ¼ 14.3 Hz, 1H), 4.15 (d, J ¼ 11.9 Hz, 1H), 4.03 ꢄ 4.00 (m, 1H),
3.76 ꢄ 3.66 (m, 3H), 1.91 ꢄ 1.71 (m, 2H), 1.61 ꢄ 1.60 (m, 2H), 1.57–1.53
(m, 4H), 1.36 ꢄ 1.25 (m, 2H). ESI-MS: [M þ Na]þ calcd for C26H32NaO4:
431.23, found: 431.33.
Menthyl-4, 6-di-O-benzyl-2, 3-dideoxy-a,b-D-erythro-hex-2-enopyrano-
side (3j):[24] a:b 5 9:1 1H NMR (500 MHz, CDCl3): a-Anomer:

JOURNAL OF CARBOHYDRATE CHEMISTRY
11
d ¼ 7.35 ꢄ 7.22 (m, 10H), 6.06 (d, J ¼ 10.3 Hz, 1H), 5.80 ꢄ 5.78 (m, 1H),
5.09 (s, 1H), 4.66 (d, J ¼ 12.1 Hz, 1H), 4.59 (d, J ¼ 11.6 Hz, 1H), 4.50 (d,
J ¼ 12.2 Hz, 1H), 4.41 (d, J ¼ 11.5 Hz, 1H), 4.16 (d, J ¼ 9.4 Hz, 1H), 4.02 (d,
J ¼ 9.5 Hz, 1H), 3.76 ꢄ 3.68 (m, 2H), 3.45 ꢄ 3.40 (m, 1H), 2.21 ꢄ 2.17 (m,
1H), 2.12 ꢄ 2.06 (m, 1H), 1.62 ꢄ 1.58 (m, 2H), 1.40 ꢄ 1.25 (m, 2H),
1.28 ꢄ 1.20 (m, 1H), 1.01 ꢄ 0.76 (m, 11H). b-Anomer: d ¼ 7.35 ꢄ 7.22 (m,
10H), 6.01 (d, J ¼ 12.0 Hz, 1H), 5.73 (d, J ¼ 12.0 Hz, 1H), 5.25 (s, 1H),
4.61 ꢄ 4.54 (m, 4H), 4.16 (m, 1H), 3.85 (m, 1H), 3.73 ꢄ 3.68 (m, 1H), 3.54
(m, 1H), 2.21 ꢄ 2.17 (m, 1H), 2.12 ꢄ 2.06 (m, 1H), 1.62 ꢄ 1.58 (m, 2H),
1.40 ꢄ 1.25 (m, 2H), 1.28 ꢄ 1.20 (m, 1H), 1.01 ꢄ 0.76 (m, 11H). ESI-MS:
[M þ Na]þ calcd for C30H40NaO4: 487.29, found: 487.42.
Cholesteryl 4, 6-di-O-benzyl-2, 3-dideoxy-D-erythro-hex-2-enopyra-
noside (3k):[24] a:b 5 5:1 1H NMR (500 MHz, CDCl3): a-Anomer:
d ¼ 7.35 ꢄ 7.23 (m, 10H), 6.06 (d, J ¼ 10.2 Hz, 1H), 5.75 (d, J ¼ 10.2 Hz,
1H), 5.25 ꢄ 5.24 (m, 1H), 5.16 (s, 1H), 4.66 (d, J ¼ 12.2 Hz, 1H), 4.60 (d,
J ¼ 11.5 Hz, 1H), 4.50 (d, J ¼ 12.1 Hz, 1H), 4.44 (d, J ¼ 11.5 Hz, 1H), 4.16
(d, J ¼ 9.3 Hz, 1H), 4.03 ꢄ 4.01(m, 1H), 3.75 ꢄ 3.68 (m, 2H), 3.60 ꢄ 3.54
(m, 1H), 2.42 ꢄ 2.31 (m, 2H), 2.04 ꢄ 1.85 (m, 5H), 1.56 ꢄ 1.47 (m, 6H),
1.33 ꢄ 1.25 (m, 5H), 1.11 ꢄ 1.09 (m, 6H), 0.99 ꢄ 0.98 (m, 5H),
0.92 ꢄ 0.90 (m, 4H), 0.87 ꢄ 0.85 (m, 7H), 0.67 (s, 3H). b-Anomer:
d ¼ 7.35 ꢄ 7.23 (m, 10H), 6.01 (d, J ¼ 12.2 Hz, 1H), 5.81 (d, J ¼ 12.2 Hz,
1H), 5.28 ꢄ 5.26 (m, 2H), 4.66 ꢄ 4.42 (m, 4H), 4.60 (d, J ¼ 11.5 Hz, 1H),
4.50 (d, J ¼ 12.1 Hz, 1H), 4.44 (d, J ¼ 11.5 Hz, 1H), 4.16 (d, J ¼ 9.3 Hz,
1H), 4.03 ꢄ 4.01 (m, 1H), 3.75 ꢄ 3.68 (m, 2H), 3.60 ꢄ 3.54 (m, 1H),
2.42 ꢄ 2.31 (m, 2H), 2.04 ꢄ 1.85 (m, 5H), 1.56 ꢄ 1.47 (m, 6H),
1.33 ꢄ 1.25 (m, 5H), 1.11 ꢄ 1.09 (m, 6H), 0.99 ꢄ 0.98 (m, 5H),
0.92 ꢄ 0.90 (m, 4H), 0.87 ꢄ 0.85 (m, 7H), 0.67 (s, 3H). ESI-MS:
[M þ Na]þ calcd for C47H66NaO4: 717.50, found: 717.58.
Dehydroepiandrosteronyl 4, 6-di-O-benzyl-2, 3-dideoxy-D-erythro-
hex-2-enopyranoside (3l):[24] a:b > 19:1 1H NMR (500 MHz, CDCl3):
d ¼ 7.35 ꢄ 7.24 (m, 10H), 6.07 (d, J ¼ 10.3 Hz, 1H), 5.75 (d, J ¼ 10.2 Hz,
1H), 5.27 (s, 1H), 5.17(s, 1H), 4.65 (d, J ¼ 12.1 Hz, 1H), 4.60 (d,
J ¼ 11.5 Hz, 1H), 4.50 (d, J ¼ 12.1 Hz, 1H), 4.44 (d, J ¼ 11.5 Hz, 1H), 4.15
(d, J ¼ 9.5 Hz, 1H), 4.03(d, J ¼ 9.5 Hz, 1H), 3.73 ꢄ 3.72 (m, 2H), 3.60 ꢄ 3.56
(m, 1H), 2.45 ꢄ 2.43 (m, 2H), 2.09 ꢄ 2.04 (m, 1H), 1.87 ꢄ 1.83 (m, 2H),
1.66 ꢄ 1.64 (m, 4H), 1.59 (m, 4H), 1.51 ꢄ 1.49 (m, 3H), 1.30 ꢄ 1.25 (m,
2H), 1.02 (m, 1H), 1.00 (s, 3H), 0.88 (s, 3H). ESI-MS: [M þ Na]þ calcd for
C47H66NaO4: 619.35, found: 619.42.
4,6-Di-O-benzyl-2,3-dideoxy-a-D-hex-2-enopyranosyl-(1fi6)-Methyl-
2,3,4-tri-O-benzyl-a-D-glucopyranoside (3m):[58] a:b > 19:1 1H NMR
(500 MHz, CDCl3): d ¼ 7.35 ꢄ 7.21 (m, 25H), 6.05 (d, J ¼ 10.4 Hz, 1H), 5.78
(d, J ¼ 10.2 Hz, 1H), 5.10 (s, 1H), 4.97 (d, J ¼ 10.9 Hz, 1H), 4.87 (d,

12
Y. MEI ET AL.
J ¼ 10.9 Hz, 1H), 4.82 ꢄ 4.76 (m, 2H), 4.65 (t, J ¼ 11.8 Hz, 2H), 4.61 (d,
J ¼ 2.4 Hz, 1H), 4.56 (d, J ¼ 12.0 Hz, 2H), 4.41 (d, J ¼ 11.5 Hz, 1H), 4.37 (d,
J ¼ 12.2 Hz, 1H), 4.18 (d, J ¼ 9.3 Hz, 1H), 4.07 (dd, J ¼ 11.2, 2.4 Hz, 1H),
3.98 (t, J ¼ 9.2 Hz, 1H), 3.85 (d, J ¼ 9.2 Hz, 1H), 3.76 (d, J ¼ 9.9 Hz, 1H),
3.71 (d, J ¼ 11.3 Hz, 1H), 3.63 ꢄ 3.58 (m, 2H), 3.55 ꢄ 3.47 (m, 2H), 3.37
(s, 3H).
4,6-Di-O-benzyl-2,3-dideoxy-a-D-hex-2-enopyranosyl-(1fi6)-Methyl-
2,3,4-tri-O-benzoyl-a-D-mannopyranoside (3n): a:b > 19:1 1H NMR
(500 MHz, CDCl3) d ¼ 8.12 (d, J ¼ 7.7 Hz, 2H), 7.97 (d, J ¼ 7.8 Hz, 2H),
7.86 (d, J ¼ 7.8 Hz, 2H), 7.59 (d, J ¼ 7.0 Hz, 1H), 7.55 ꢄ 7.47 (m, 3H), 7.44
(t, J ¼ 7.0 Hz, 1H), 7.41 ꢄ 7.27 (m, 14H), 6.07 (t, J ¼ 9.2 Hz, 2H), 5.86 (d,
J ¼ 10.0 Hz, 1H), 5.72 (dd, J ¼ 10.3, 1.8 Hz, 1H), 5.68 (s, 1H), 5.11 (s, 1H),
5.00 (s, 1H), 4.62 (d, J ¼ 11.5 Hz, 1H), 4.54 (d, J ¼ 12.2 Hz, 1H), 4.47 (d,
J ¼ 11.5 Hz, 1H), 4.34 (d, J ¼ 12.2 Hz, 1H), 4.25 (t, J ¼ 9.5 Hz, 2H), 4.09 (d,
J ¼ 11.0 Hz, 1H), 3.98 (d, J ¼ 9.1 Hz, 1H), 3.79 (d, J ¼ 10.8 Hz, 1H), 3.67 (d,
J ¼ 10.6 Hz, 1H), 3.53 (s, 3H), 3.45 (d, J ¼ 10.7 Hz, 1H). 13C NMR
(125 MHz, CDCl3) 165.61, 165.60, 165.29, 138.32, 138.18, 133.48, 133.32,
133.13, 131.19, 130.05, 129.85, 129.50, 129.40, 129.29, 128.65, 128.46,
128.41, 128.34, 128.32, 127.91, 127.89, 127.75, 127.62, 126.14, 98.62, 94.90,
73.39, 71.17, 70.51, 70.41, 70.22, 69.72, 69.37, 68.57, 67.30, 66.74, 55.60.
HRMS (ESIþ): m/z calcd. for C48H46NaO12 [M þ Na]þ 837.2888,
found 837.2881.
4,6-Di-O-benzyl-2,3-dideoxy-a-D-hex-2-enopyranosyl-(1fi6)-4-
Methoxyphenyl-2-O-acetyl-4-O-benzyl-a-L-rhamnopyranoside
(3o):
1
a:b > 19:1 H NMR (500 MHz, CDCl3) d ¼ 7.32 ꢄ 7.25 (m, 10H), 7.19 (d,
J ¼ 9.1 Hz, 5H), 6.98 (d, J ¼ 8.3 Hz, 2H), 6.82 (d, J ¼ 8.2 Hz, 2H), 6.09 (d,
J ¼ 10.2 Hz, 1H), 5.66 (d, J ¼ 10.2 Hz, 1H), 5.48 (s, 1H), 5.30 (s, 1H), 5.26
(s, 1H), 4.84 (d, J ¼ 10.9 Hz, 1H), 4.64 (d, J ¼ 10.9 Hz, 1H), 4.59 (d,
J ¼ 12.2 Hz, 1H), 4.53 (d, J ¼ 11.5 Hz, 1H), 4.48 (dd, J ¼ 9.5, 3.0 Hz, 1H),
4.36 (d, J ¼ 11.4 Hz, 1H), 4.27 (t, J ¼ 11.5 Hz, 2H), 3.92 (dd, J ¼ 15.9,
7.1 Hz, 2H), 3.77 (s, 3H), 3.42 (t, J ¼ 9.5 Hz, 1H), 3.38 (s, 2H), 1.31 (d,
J ¼ 6.2 Hz, 3H). 13C NMR (125 MHz, CDCl3) 170.35, 154.99, 150.17,
138.30, 138.13, 138.11, 131.23, 128.27, 128.24, 128.22, 127.99, 127.86,
127.68, 127.61, 127.55, 127.52, 126.27, 117.64, 114.59, 96.84, 91.38, 79.10,
75.37, 73.59, 73.27, 71.32, 70.13, 69.53, 68.59, 68.54, 68.07, 55.65, 21.07,
17.97. HRMS (ESIþ): m/z calcd. for C42H46NaO10 [M þ Na]þ 733.2990,
found 733.2983.
4,6-Di-O-benzyl-2,3-dideoxy-a,b-D-hex-2-enopyranosyl-(1fi6)-1,2;3,4-
1
di-O-isopropylidene-a-D-galactopyranoside (3p):[24] a:b 5 4:1 H NMR
(500 MHz, CDCl3): a-Anomer: d ¼ 7.34 ꢄ 7.23 (m, 10H), 6.06 (d,
J ¼ 10.3 Hz, 1H), 5.78 (dt, J ¼ 10.3 Hz, J ¼ 2.1 Hz, 1H), 5.52 (d, J ¼ 5.0 Hz,

JOURNAL OF CARBOHYDRATE CHEMISTRY
13
1H), 5.09 (s, 1H), 4.66 (d, J ¼ 12.2 Hz, 1H), 4.60 ꢄ 4.56 (m, 3H), 4.49 (d,
J ¼ 12.3 Hz, 1H), 4.43 (d, J ¼ 11.5 Hz, 1H), 4.31 ꢄ 4.26 (m, 2H), 4.23 (d,
J ¼ 9.4 Hz, 1H), 4.02 ꢄ 4.00 (m, 3H), 3.85 ꢄ 3.84 (m, 1H), 3.80 ꢄ 3.75 (m,
2H), 3.74 ꢄ 3.70 (m, 1H), 1.52 (s, 3H), 1.44 (s, 3H),1.34 ꢄ 1.26 (m, 6H).
b-Anomer: d ¼ 7.28 ꢄ 7.23 (m, 10H), 6.01 (d, J ¼ 12.3 Hz, 1H), 5.92 (dt,
J ¼ 12.3 Hz, 1H), 5.55 (d, J ¼ 5.0 Hz, 1H), 5.20 (s, 1H,) , 4.66 ꢄ 4.42 (m,
6H), 4.31 ꢄ 4.26 (m, 2H), 4.23 (d, J ¼ 9.4 Hz, 1H), 4.02 ꢄ 4.00 (m, 3H),
3.85 ꢄ 3.84 (m, 1H), 3.80 ꢄ 3.75 (m, 2H), 3.74 ꢄ 3.70 (m, 1H), 1.52 (s, 3H),
þ
1.44 (s, 3H),1.34 ꢄ 1.26 (m, 6H). ESI-MS: [M þ Na]
calcd for
C32H40NaO9: 591.27, found: 591.33.
Phenyl 4, 6-di-O-benzyl-2, 3-dideoxy-a, b-D-erythro-hex-2-enopyranoside
1
(3q)[59]: a:b 5 9:1 H NMR (500MHz, CDCl3): a-Anomer: d ¼ 7.34 ꢄ 7.25
(m, 12H), 7.13 ꢄ 7.11 (m, 2H), 7.02ꢄ 7.01 (m, 1H), 6.20 (d, J ¼ 10.1 Hz, 1H),
5.91 (d, J ¼ 10.2 Hz, 1H), 5.70 (s, 1H), 4.65 ꢄ 4.45 (m, 4H), 4.29 (d, J¼ 9.5 Hz,
1H), 4.09 (d, J ¼ 9.4 Hz, 1H), 3.76ꢄ 3.66 (m, 2H). b-Anomer: d ¼ 7.34 ꢄ 7.25
(m, 12H), 7.13 ꢄ 7.11 (m, 2H), 7.02ꢄ 7.01 (m, 1H), 6.14 (d, J ¼ 12.1 Hz, 1H),
6.03 (d, J ¼ 12.2 Hz, 1H), 5.79 (s, 1H), 4.65 ꢄ 4.45 (m, 4H), 4.23 ꢄ 4.21 (m,
1H), 4.07 ꢄ 4.02 (m, 1H), 3.76 ꢄ 3.66 (m, 2H). 13C NMR (125MHz, CDCl3): d
(ppm): 157.37, 138.08, 137.95, 131.68, 129.39, 129.36, 128.39, 128.26, 127.94,
127.87, 127.57, 125.70, 122.04, 117.02, 93.52, 73.28, 71.23, 70.06, 68.63, 20.55.
ESI-MS: [M þ Na]þ calcd for C26H26NaO4: 425.18, found: 425.25.
4-Methylphenyl 4, 6-di-O-benzyl-2, 3-dideoxy-a, b-D-erythro-hex-2-
1
enopyranoside (3r):[60] a:b 5 7:1 H NMR (500 MHz, CDCl3): a-Anomer:
d ¼ 7.33 ꢄ 7.24 (m, 10H), 7.07 ꢄ 7.05 (m, 2H), 7.02 ꢄ 6.98 (m, 2H), 6.19 (d,
J ¼ 10.5 Hz, 1H), 5.90 (d, J ¼ 10.5 Hz, 1H), 5.65 (s, 1H), 4.64 ꢄ 4.45 (m,
4H), 4.26(d, J ¼ 9.0 Hz, 1H), 4.08 (d, J ¼ 9.0 Hz, 1H), 3.75–3.69 (m, 2H),
1.28 (s, 9H). b-Anomer: d ¼ 7.33 ꢄ 7.24 (m, 10H), 7.07 ꢄ 7.05 (m, 2H),
7.02 ꢄ 6.98 (m, 2H), 6.13 (d, J ¼ 12.5 Hz, 1H), 6.00 (d, J ¼ 12.5 Hz, 1H),
5.73 (s, 1H), 4.64 ꢄ 4.45 (m, 4H), 4.19 ꢄ 4.18 (m, 1H), 4.02 ꢄ 4.00 (m, 1H),
3.75 ꢄ 3.69 (m, 2H), 2.29 (s, 3H). 13C NMR (125 MHz, CDCl3): 155.24,
138.12, 137.98, 131.57, 131.41, 129.82, 128.37, 128.27, 127.82, 127.76,
127.60, 127.55, 125.85, 117.02, 93.52, 73.28, 71.23, 70.06, 68.63, 20.55. ESI-
MS: [M þ Na]þ calcd for C27H28NaO4: 439.20, found: 439.25.
p-tert-Butylphenyl 4, 6-di-O-benzyl-2, 3-dideoxy-a, b-D-erythro-hex-2-
1
enopyranoside (3 s)[61]: a:b 5 7:1 H NMR (500 MHz, CDCl3): a-Anomer:
d ¼ 7.33–7.26 (m, 12H), 7.06–7.05 (m, 2H), 6.19 (d, J ¼ 10.5 Hz, 1H), 5.90
(d, J ¼ 10.0 Hz, 1H), 5.66 (s, 1H), 4.65 ꢄ 4.46 (m, 4H), 4.27(d, J ¼ 9.0 Hz,
1H), 4.07 (d, J ¼ 8.5 Hz, 1H), 3.76 ꢄ 3.66 (m, 2H), 2.28 (s, 3H). b-Anomer:
d ¼ 7.33–7.26 (m, 12H), 7.06–7.05 (m, 2H), 6.09 (d, J ¼ 12.5 Hz, 1H), 6.01
(d, J ¼ 12.5 Hz, 1H), 5.76(s, 1H), 4.64 ꢄ 4.62(m, 2H), 4.48 ꢄ 4.61 (m, 2H),
4.25 ꢄ 4.21 (m, 1H), 4.05 ꢄ 4.03 (m, 1H), 3.76 ꢄ 3.66 (m, 2H), 2.25 (s, 9H).

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Y. MEI ET AL.
13C NMR (125 MHz, CDCl3): 155.19, 144.79, 138.14, 137.98, 131.56, 128.37,
128.27, 127.84, 127.82, 127.76, 127.54, 126.15, 125.86, 116.54, 93.51, 73.31,
71.23, 70.10, 70.03, 68.65, 34.1 31.48. ESI-MS: [M þ Na]þ calcd for
C30H34NaO4: 481.25, found: 481.33.
Methoxyphenyl 4, 6-di-O-benzyl-2, 3-dideoxy-a, b-D-erythro-hex-2-
1
enopyranoside (3t):[62] a:b 5 6:1 H NMR (500 MHz, CDCl3): a-Anomer:
d ¼ 7.34 ꢄ 7.25 (m, 10H), 7.06 ꢄ 7.04 (m, 2H), 6.80 ꢄ 6.78 (m, 2H), 6.19 (d,
J ¼ 10.2 Hz, 1H), 5.92 (d, J ¼ 10.2 Hz, 1H), 5.56 (s, 1H), 4.65 ꢄ 4.46 (m,
4H), 4.24 (d, J ¼ 9.5 Hz, 1H), 4.11 (d, J ¼ 14.2 Hz, 1H), 3.76 ꢄ 3.69 (m, 5H).
b-Anomer: d ¼ 7.34 ꢄ 7.25 (m, 10H), 7.06 ꢄ 7.04 (m, 2H), 6.80 ꢄ 6.78 (m,
2H), 6.12 (d, J ¼ 12.2 Hz, 1H), 6.01 (d, J ¼ 12.2 Hz, 1H), 5.67 (s, 1H),
4.65 ꢄ 4.46 (m, 4H), 4.18 ꢄ 4.15 (m, 1H), 4.06 ꢄ 4.03 (m, 1H), 3.74 ꢄ 3.68
(m, 5H) 13C NMR (125 MHz, CDCl3): 154.93, 151.38, 138.13, 137.96,
131.50, 128.38, 128.27, 127.81, 127.77, 127.55, 125.94, 118.68, 117.94,
114.44, 94.30, 73.29, 71.18, 70.12, 69.96, 68.77, 55.60. ESI-MS: [M þ Na]þ
calcd for C27H28NaO5: 455.19, found: 455.25.
2,4-Dimethylphenyl 4, 6-di-O-benzyl-2, 3-dideoxy-a, b-D-erythro-hex-
1
2-enopyranoside (3 u): a:b 5 9:1 H NMR (500 MHz, CDCl3): a-Anomer:
d ¼ 7.33 ꢄ 7.24 (m, 10H), 7.11 ꢄ 7.09 (m, 1H), 6.94 ꢄ 6.90 (m, 2H), 6.18 (d,
J ¼ 10.5 Hz, 1H), 5.92 (d, J ¼ 10.0 Hz, 1H), 5.61 (s, 1H), 4.65 ꢄ 4.46 (m,
4H), 4.27 (d, J ¼ 9.5 Hz, 1H), 4.09 (d, J ¼ 9.5 Hz, 1H), 3.77 ꢄ 3.67 (m, 2H),
2.25 (s, 3H), 2.17 (s, 3H). b-Anomer: d ¼ 7.31 ꢄ 7.24 (m, 10H), 7.11 ꢄ 7.09
(m, 1H), 6.92 ꢄ 6.90 (m, 2H), 6.15 (d, J ¼ 12.5 Hz, 1H), 6.02 (d, J ¼ 12.5 Hz,
1H), 5.68 (s, 1H), 4.64 ꢄ 4.60 (m, 2H), 4.50 ꢄ 4.46 (m, 2H), 4.17 ꢄ 4.15 (m,
1H), 4.07 ꢄ 4.05 (m, 1H), 3.77 ꢄ 3.67 (m, 2H), 2.25 (s, 3H), 2.17 (s, 3H).
13C NMR (125 MHz, CDCl3): 153.60, 138.14, 137.93, 131.35, 131.33, 128.39,
128.27, 127.90, 127.83, 127.80, 127.54, 127.10, 126.03, 115.64, 93.84, 73.32,
71.40, 70.15, 70.13, 68.65, 20.51, 16.25. ESI-MS: [M þ Na]þ calcd for
C28H30NaO4: 453.21, found: 453.33.
Acknowledgment
We sincerely thank the analytic center of East China Normal University for data
measurements.
Funding
The project was supported by the Natural Science Foundation of Shanghai [11ZR1410400],
large instruments Open Foundation of East China Normal University [20161043], DAXIA
Science Research Foundation of East China Normal University [2011DX-288] and National
Undergraduate Training Program for Innovation and Entrepreneurship [201710269030G].

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15
References
[1] Liao, H.; Leng, W.; Hoang, K.; Yao, H.; He, J.; Voo, A.; Liu, X. Asymmetric synthe-
ses of 8-oxabicyclo[3,2,1]octane and 11-oxatricyclo[5.3.1.0]undecane from glycals.
Chem. Sci. 2017, 8(9), 6656–6661. doi: 10.1039/C7SC02625K.
[2] Park, Y.; Harper, K. C.; Kuhl, N.; Kwan, E. E.; Liu, R. Y.; Jacobsen, E. N.
Macrocyclic bis-thioureas catalyze stereospecific glycosylation reactions. Science.
2017, 355(6321), 162–166. doi: 10.1126/science.aal1875.
[3] Kartika, R.; Frein, J. D.; Taylor, R. E. Electrophile-induced ether transfer: stereo-
selective synthesis of 2,6-disubstituted-3,4-dihydropyrans. J. Org. Chem. 2008,
73(14), 5592–5594. doi: 10.1021/jo800704d.
[4] Gu, Z.; Zhang, X.; Zhang, J.; Xing, G. Highly efficient a-C-sialylation promoted by
(p-Tol)2SO/Tf2O with N-acetyl-5-N,4-O-oxazolidione protected thiosialoside as
donor. Org. Biomol. Chem. 2013, 11(30), 5017–5022. doi: 10.1039/c3ob40876k.
[5] Li, C.; Wang, L. Chemoenzymatic methods for the synthesis of glycoproteins. Chem.
Rev. 2018, 118(17), 8359–8413. doi: 10.1021/acs.chemrev.8b00238.
[6] Lowary, T. L. Twenty years of mycobacterial glycans: furanosides and beyond. Acc.
Chem. Res. 2016, 49(7), 1379–1388. doi: 10.1021/acs.accounts.6b00164.
[7] Schmidt, R. R.; Angerbauer, R. A short synthesis of racemic uronic acids and 2,3-
anhydrouronic acids. Carbohydr. Res. 1981, 89(1), 159–162. doi: 10.1016/S0008-
6215(00)85239-8.
[8] Schmidt, R. R.; Angerbauer, R. Simplede-novo Synthesis of Reactive
Pseudoglycals(Hex-2-enopyranosides)—Stereospecifica-Glycoside Coupling. Angew.
Chem. Int. Ed. Engl. 1977, 16(11), 783–784. doi: 10.1002/anie.197707832.
[9] Gordon, D. M.; Danishefsky, S. J. Ritter-like reactions of 1,2-anhydropyranose deriv-
atives. J. Org. Chem. 1991, 56(11), 3713–3715. doi: 10.1021/jo00011a050.
[10] Ernst, C.; Klaffke, W. Chemical synthesis of uridine diphospho-D-xylose and UDP-
L-arabinose. J. Org. Chem. 2003, 68(14), 5780–5783. doi: 10.1021/jo034379u.
€
[11] Fernandes, A.; Dell’Olmo, M.; Tatibouet, A.; Imberty, A.; Philouze, C.; Rollin, P.
Dramatic effect of PSE clamping on the behaviour of d-glucal under Ferrier I condi-
tions. Tetrahedron Lett. 2008, 49(21), 3484–3488. doi: 10.1016/j.tetlet.2008.03.093.
[12] Tanmaya, P. Vinyl sulfone-modified carbohydrates: an inconspicuous group of
chiral building blocks. Tetrahedron 2008, 64, 3605-3628. doi: 10.1016/j.tet.2008.01.
069.
[13] Neyts, J.; De Clercq, E.; Singha, R.; Chang, Y. H.; Das, A. R.; Chakraborty, S. K.;
Hong, S. C.; Tsay, S.-C.; Hsu, M.-H.; Hwu, J. R. Structure-activity relationship of
new anti-hepatitis C virus agents: heterobicycle-coumarin conjugates. J. Med. Chem.
2009, 52(5), 1486–1490. doi: 10.1021/jm801240d.
[14] Leibeling, M.; Koester, D. C.; Pawliczek, M.; Schild, S. C.; Werz, D. B. Domino
access to highly substituted chromans and isochromans from carbohydrates. Nat.
Chem. Biol. 2010, 6(3), 199–201. doi: 10.1038/nchembio.302.
[15] Leibeling, M.; Milde, B.; Kratzert, D.; Stalke, D.; Werz, D. B. Intermolecular twofold
carbopalladation/cyclization sequence to access chromans and isochromans from
carbohydrates. Chemistry 2011, 17(36), 9888–9892. doi: 10.1002/chem.201101917.
[16] Ferrier, R. J.; Prasad, N. Unsaturated carbohydrates. Part IX. Synthesis of 2,3-
dideoxy-a- D -erythro-hex-2-enopyranosides from tri-O-acetyl- D -glucal. J. Chem.
Soc. C. 1969, 0(4), 570–575. doi: 10.1039/J39690000570.
[17] Ferrier, R.J.; Hoberg, J.O. Synthesis and reactions of unsaturated sugars. Adv.
Carbohydr. Chem. Biochem. 2003, 58, 55–119. doi: 10.1016/s0065-2318(03)58003-9.

16
Y. MEI ET AL.
[18] Gomez, A. M.; Miranda, S.; Lopez, J. C. Ferrier rearrangement: an update on recent
developments. Carbohydr. Chem. 2017, 42, 210–247. doi: 10.1039/9781782626657-
00210.
[19] Gomez, A. M.; Lobo, F.; Uriel, C.; Lopez, J. C. Recent developments in the Ferrier
rearrangement. Eur. J. Org. Chem. 2013, 2013(32), 7221–7262. doi: 10.1002/ejoc.
201300798.
[20] Jiang, N.; Wu, Z.; Dong, Y.; Xu, X.; Liu, X.; Zhang, J. Progress in the synthesis of
2,3-unsaturated Glycosides. Coc. 2020, 24(2), 184–199. doi: 10.2174/
1385272824666200130111142.
[21] Bihari, M. K.; Kandasamy, J. Tris(Pentafluorophenyl)Borane-Driven stereoselective
O -glycosylation with glycal donors under mild condition. Asian J. Org. Chem.
2019, 8(4), 549–554. doi: 10.1002/ajoc.201900055.
[22] Zhou, J.; Zhang, B.; Yang, G.; Chen, X.; Wang, Q.; Wang, Z.; Zhang, J.; Tang, J. A
facile H2SO4/4 Å molecular sieves catalyzed synthesis of 2,3-unsaturated O-glyco-
sides via Ferrier-type rearrangement. Synlett 2010, 2010(06), 893–896. doi: 10.1055/
s-0029-1219539.
[23] Zhou, J. F.; Chen, X.; Wang, Q. B.; Zhang, B.; Zhang, L. Y.; Yusulf, A.; Wang, Z. F.;
Zhang, J. B.; Tang, J. H2SO4-SiO2: highly efficient and novel catalyst for the Ferrier-
type glycosylation. Chin. Chem. Lett. 2010, 21(8), 922–926. doi: 10.1016/j.cclet.2010.
03.013.
[24] Zhang, J.; Zhang, B.; Zhou, J.; Chen, H.; Li, J.; Yang, G.; Wang, Z.; Tang, J. A Facile
H2SO4-SiO2–catalyzed ferrier rearrangement of 3,4,6-tri-O-benzyl-D-glucal. J.
Carbohydr. Chem. 2013, 32(5–6), 380–391. doi: 10.1080/07328303.2013.809093.
[25] Sau, A.; Galan, M. C. Palladium-catalyzed a-stereoselective O-glycosylation of O(3)-
acylated glycals. Org. Lett. 2017, 19(11), 2857–2860. doi: 10.1021/acs.orglett.7b01092.
[26] Chen, P.; Su, J. Gd(OTf)3 catalyzed preparation of 2,3-unsaturated O-, S-, N-, and
C-pyranosides from glycals by Ferrier rearrangement. Tetrahedron 2016, 72(1),
84–94. doi: 10.1016/j.tet.2015.11.002.
[27] Roy, R.; Rajasekaran, P.; Mallick, A.; Vankar, Y. D. Gold(III) chloride and phenyla-
cetylene: a catalyst system for the ferrier rearrangement, and O-glycosylation of 1-
O-acetyl sugars as glycosyl donors. Eur. J. Org. Chem. 2014, 2014(25), 5564–5573.
doi: 10.1002/ejoc.201402606.
[28] Chen, H.; Luo, X.; Qiu, S.; Sun, G.; Zhang, J. TMSOTf mediated stereoselective syn-
thesis of a-C-glycosides from unactivated aryl acetylenes. Glycoconj. J. 2017, 34(1),
13–20. doi: 10.1007/s10719-016-9718-7.
[29] Lopez, J. C.; Fraser-Reid, B. n-Pentenyl esters facilitate an oxidative alternative to
the Ferrier rearrangement. An expeditious route to sucrose. J. Chem. Soc. Chem.
Commun. 1992, 0(2), 94–96. doi: 10.1039/C39920000094.
[30] Pachamuthu, K.; Vankar, Y. D. Ceric ammonium nitrate-catalyzed tetrahydropyra-
nylation of alcohols and synthesis of 2-deoxy-O-glycosides. J. Org. Chem. 2001,
66(22), 7511–7513. doi: 10.1021/jo0103322.
[31] Lin, H. C.; Du, W. P.; Chang, C. C.; Lin, C.H. Different reaction routes found in
acid-catalyzed glycosylation of endo- and exo-glycals: competition between Ferrier
rearrangement and protonation. Tetrahedron Lett 2005, 46(30), 5071–5076. doi: 10.
1016/j.tetlet.2005.05.061.
[32] Rauter, A. P.; Almeida, T.; Xavier, N. M.; Siopa, F.; Vicente, A. I.; Lucas, S. D.;
^
Marques, J. P.; Ramoa Ribeiro, F.; Guisnet, M.; Ferreira, M. J. Acid zeolites as effi-
cient catalysts for O- and S-glycosylation. J. Mol. Catal. A Chem. 2007, 275(1–2),
206–213. doi: 10.1016/j.molcata.2007.06.002.

JOURNAL OF CARBOHYDRATE CHEMISTRY
17
[33] Zhang, G.; Liu, Q.; Shi, L.; Wang, J. X. Ferric sulfate hydrate-catalyzed O-glycosyla-
tion using glycals with or without microwave irradiation. Tetrahedron 2008, 64(2),
339–344. doi: 10.1016/j.tet.2007.10.097.
[34] Enthaler, S.; Junge, K.; Beller, M. Sustainable metal catalysis with iron: from rust to
a rising star? Angew. Chem. Int. Ed. Engl. 2008, 47(18), 3317–3321. doi: 10.1002/
anie.200800012.
[35] Salunke, S. B.; Babu, N. S.; Chen, C.T. Iron(III) chloride as an efficient catalyst for
stereoselective synthesis of glycosyl azides and a cocatalyst with Cu(0) for the subse-
quent click chemistry. Chem. Commun. (Camb.) 2011, 47(37), 10440–10442. doi: 10.
1039/c1cc13370e.
[36] Ding, Y.; Zhang, S.-Y.; Chen, Y.-C.; Fan, S.-X.; Tian, J.-S.; Loh, T.-P. Regioselective
C–H Amidation of (Alkyl)arenes by Iron(II) Catalysis. Org. Lett. 2019, 21(8),
2736–2739. doi: 10.1021/acs.orglett.9b00697.
[37] Piontek, A.; Bisz, E.; Szostak, M. Iron-catalyzed cross-couplings in the synthesis of
pharmaceuticals: in pursuit of sustainability. Angew. Chem. Int. Ed. Engl. 2018,
57(35), 11116–11128. doi: 10.1002/anie.201800364.
[38] Jose, C. A.; Antonio, L. P.; Avelino, C. Iron-Catalysed Markovnikov Hydrothiolation
of Styrenes. Adv. Synth. Catal. 2012, 354, 678–687. doi: 10.1002/adsc.201100731.
€
[39] Bauer, I.; Knolker, H.-J. Iron catalysis in organic synthesis. Chem. Rev. 2015, 115(9),
3170–3387. doi: 10.1021/cr500425u.
[40] Xolin, A.; Norsikian, S.; Boyer, F.; Beau, J. Iron(III)-triflate-catalyzed multiple glyco-
sylations with peracetylated b-d-glucosamine. Eur. J. Org. Chem. 2016, 2016(20),
3408–3418. doi: 10.1002/ejoc.201600457.
[41] Mukherjee, M. M.; Basu, N.; Ghosh, R. Iron(III) chloride modulated selective 1,2-
trans glycosylation based on glycosyl trichloroacetimidate donors and its application
in orthogonal glycosylation. RSC Adv. 2016, 6(107), 105589–105605. doi: 10.1039/
C6RA21859H.
[42] Qiu, S.; Zhang, W.; Sun, G.; Wang, Z.; Zhang, J. A facile and direct glycosidation
method for the synthesis of 2-deoxy-a-rhamnosides catalyzed by ferric chloride.
ChemistrySelect 2016, 1(15), 4840–4844. doi: 10.1002/slct.201600802.
[43] Qiu, S.; Sun, G.; Ding, Z.; Chen, H.; Zhang, J. Ferric chloride: an eco-friendly cata-
lyst for the stereoselective synthesis of 2-deoxy aryl-O-rhamnosides. Synlett. 2017,
28(15), 2024–2029. doi: 10.1055/s-0036-1588864.
[44] Sun, G.; Wu, Y.; Liu, A.; Qiu, S.; Zhang, W.; Wang, Z.; Zhang, J. Substoichiometric
FeCl3 activation of propargyl glycosides for the synthesis of disaccharides and glyco-
conjugates. Synlett 2018, 29(5), 668–672. doi: 10.1055/s-0036-1591525.
[45] Masson, C.; Soto, J.; Bessodes, M. Ferric chloride: a new and very efficient catalyst
for the ferrier glycosylation reaction. Synlett 2000, 9, 1281–1282. doi: 10.1055/s-
2000-7138.
[46] Chen, P.; Wang, S. Iron(III) triflate, a new efficient catalyst for Type I Ferrier
Rearrangement. Tetrahedron 2012, 68(27–28), 5356–5362. doi: 10.1016/j.tet.2012.04.
115.
[47] Tilve, R. D.; Alexander, M. V.; Khandekar, A. C.; Samant, S. D.; Kanetkar, V. R.
Synthesis of 2,3-unsaturated glycopyranosides by Ferrier rearrangement in FeCl3
based ionic liquid. J. Mol. Catal. A: Chem. 2004, 223(1–2), 237–240. doi: 10.1016/j.
molcata.2003.11.044.
[48] Zhou, J.; Chen, H.; Shan, J.; Li, J.; Yang, G.; Chen, X.; Xin, K.; Zhang, J.; Tang, J.
FeCl3 ꢁ6H2 O/C: an efficient and recyclable catalyst for the synthesis of 2,3-

18
Y. MEI ET AL.
unsaturated O- and S- glycosides. J. Carbohydr. Chem 2014, 33(6), 313–325. doi: 10.
1080/07328303.2014.941995.
[49] Sun, G.; Qiu, S.; Ding, Z.; Chen, H.; Zhou, J.; Wang, Z.; Zhang, J. Magnetic Core-
Shell Fe3O4@C-SO3H as an Efficient and Renewable ‘Green Catalyst’ for the
Synthesis of O-2,3-Unsaturated Glycopyranosides. Synlett. 2017, 28, 347–352. doi:
10.1055/s-0036-1588891.
[50] Dong, Y.; Ding, Z.; Guo, H.; Zhou, L.; Jiang, N.; Chen, H.; Qiu, S.; Xu, X.; Zhang, J.
Transition-metal-catalyzed ketone a-alkylation and alkenylation with simple alkenes
and alkynes through a dual activation strategy. Synlett. 2019, 30(6), 1419–1426. doi:
10.1055/s-0037-1611855.
[51] Guo, H.; Si, W.; Li, J.; Yang, G.; Tang, T.; Wang, Z.; Tang, J.; Zhang, J. An unex-
pected FeCl3/C-catalyzed b-stereoselective glycosylation in the presence of the C(2)-
benzyl group. J. Synthesis. 2019, 51(15), 2984–3000. doi: 10.1055/s-0037-1611801.
[52] Calleja, G.; Melero, J.A.; Martinez, F.; Molina, R. Activity and resistance of iron-con-
taining amorphous, zeolitic and mesostructured materials for wet peroxide oxidation
of phenol. Water Res. 2005, 39(9), 1741–1750. doi: 10.1016/j.watres.2005.02.013.
[53] He, L.; Du, G.; Gao, J.; Wang, X.; Wang, W., Dai, B., Synthesis of tributyl citrate
catalyzed by active carbon supported solid acid Chem. Res. Appli. 2013, 25,
1628–1631. doi: 10.3969/j.issn.1004-1656.2013.12.003.
[54] Yang, Y.; Zhang, X.; Yu, B. O-Glycosylation methods in the total synthesis of com-
plex natural glycosides. Nat. Prod. Rep. 2015, 32(9), 1331–1335. doi: 10.1039/
c5np00033e.
[55] Cottreau, K.; Spencer, C.; Wentzell, J.; Graham, C. L.; Borissow, C. N.; Jakeman,
D. L.; Mcfarland, S. A. Diverse DNA-cleaving capacities of the jadomycins through
precursor-directed biosynthesis. Org. Lett. 2010, 12(6), 1172–1175. doi: 10.1021/
ol902907r.
[56] Kusumi, S.; Sasaki, K.; Wang, S.; Watanabe, T.; Takahashi, D.; Toshima, K. Effective
and chemoselective glycosylations using 2,3-unsaturated sugars. Org. Biomol. Chem.
2010, 8(14), 3164–3178. doi: 10.1039/c004204h.
[57] Sau, A.; Palo, C.; Galan, M. C. Substrate-controlled direct a-stereoselective synthesis
of deoxyglycosides from glycals using B(C6F5)3 as catalyst. J. Org. Chem. 2019,
84(5), 2415–2424. doi: 10.1021/acs.joc.8b02613.
[58] Ghosh, T.; Mukherji, A.; Kancharla, P. K. Sterically hindered 2,4,6-tri- tert-butylpyr-
idinium salts as single hydrogen bond donors for highly stereoselective glycosylation
reactions of glycals. Org. Lett. 2019, 21(10), 3490–3495. doi: 10.1021/acs.orglett.
9b00626.
[59] Chen, P.; Li, S. Y(OTf)3 as a highly efficient catalyst in Ferrier Rearrangement for
the synthesis of O- and S-2,3-unsaturated glycopyranosides. Tetrahedron Lett 2014,
55(42), 5813–5816. doi: 10.1016/j.tetlet.2014.08.092.
[60] Kumaran, E.; Santhi, M.; Balasubramanian, K. K.; Bhagavathy, S. Montmorillonite
K-10 clay-catalyzed Ferrier rearrangement of 2-C-hydroxymethyl-d-glycals, 3,4,6-tri-
O-alkyl-d-glycals, and 3,4-(dihydro-2H-pyran-5-yl)methanol: a few unexpected dom-
ino transformations. Carbohydr. Res. 2011, 346(13), 1654–1661. doi: 10.1016/j.carres.
2011.03.027.
[61] Wernicke, A.; Sinou, D. Synthesis of unsaturated C -glycosyl glycines. J. Carbohydr.
Chem. 2001, 20(2), 181–190. doi: 10.1081/CAR-100103957.
[62] Nagaraj, P.; Ramesh, N. G. Direct Ferrier rearrangement on unactivated glycals cata-
lyzed by indium(III) chloride. Tetrahedron Lett. 2009, 50(27), 3970–3973. doi: 10.
1016/j.tetlet.2009.04.084.