Regioselective benzoylation of glycopyranosides by benzoic anhydride in the presence of Cu(CF3COO)2

Article abstract of DOI:10.1016/j.carres.2012.06.020

Benzoylation of methyl and benzyl glycopyranosides by benzoic anhydride in acetonitrile in the presence of copper(II) trifluoroacetate as a promoter has given monobenzoates with a good yield and high regioselectivity. The composition of monobenzoates depended both on a configuration of hydroxyl groups and on a configuration of aglycone. The simple syntheses of the monobenzoates of some glycosides are offered.

Full text of DOI:10.1016/j.carres.2012.06.020

Carbohydrate Research 359 (2012) 111–119
Contents lists available at SciVerse ScienceDirect
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Note
Regioselective benzoylation of glycopyranosides by benzoic anhydride
in the presence of Cu(CF3COO)2
⇑
Evgeny V. Evtushenko
G.B. Elyakov Pacific Institute of Bioorganic Chemistry, Far-East Branch, Russian Academy of Sciences, Vladivostok 690022, Russian Federation
a r t i c l e i n f o
a b s t r a c t
Article history:
Benzoylation of methyl and benzyl glycopyranosides by benzoic anhydride in acetonitrile in the presence
of copper(II) trifluoroacetate as a promoter has given monobenzoates with a good yield and high regiose-
lectivity. The composition of monobenzoates depended both on a configuration of hydroxyl groups and
on a configuration of aglycone. The simple syntheses of the monobenzoates of some glycosides are
offered.
Received 10 April 2012
Received in revised form 22 June 2012
Accepted 30 June 2012
Available online 9 July 2012
Ó 2012 Elsevier Ltd. All rights reserved.
Keywords:
Glycopyranosides
Regioselective benzoylation
Copper(II) trifluoroacetate
Carbohydrates and glycoconjugates are abundant in nature and
often play an important role in live processes. Their study demands
synthetic oligosaccharides. Synthesis of oligosaccharides usually
involves the strategy based on blocking and deblocking of hydroxyl
groups that demands multistages and time. Regioselective intro-
duction of protective groups in carbohydrates could become an
alternative approach for getting intermediates in oligosaccharide
synthesis. Earlier for regioselective acylation of carbohydrates both
enzymic1 and chemical approaches2–24 were used. Among the
latter copper,2–5 mercury,3 nickel,6 platinum6 and zinc6 chelates,
tin-organic,7–18 organoboron19 and organosilicon20 compounds,
amines,21–24 organocatalysts25,26 and TMS ethers27–29 were used.
However, despite certain advances in this area, regioselective
protection of hydroxyl groups in sugars is still a challenge in organ-
ic synthesis.
In the present work we wanted to study the effect of complex-
ation of carbohydrates with transition metals and in particular
with copper(II) in aprotic solvents on relative reactivity of hydroxyl
groups of carbohydrates in benzoylation.
It is of interest to note that salts of transition metals as catalysts
were not active in benzoylation of glycosides by benzoic anhy-
dride. However, the use of a little surplus of the salts in comparison
with stoichiometric quantities often showed their efficiency in
benzoylation (Table 1).
Table 1 shows that zinc(II), nickel(II), cobalt(II) and gadolin-
ium(III) salts (entries 14–17) moderately activate the benzoylation
of methyl a-L-rhamnopyranoside 1 and do not lead to the consid-
erable distinctions in amounts of 2- and 3-benzoates in reaction
mixtures. However, the use of trifluoroacetate (entry 4), triflate
(entry 10) and perchlorate (entry 11) of copper(II) showed forma-
tion of 2-benzoate with high yield and regioselectivity in this reac-
tion. Acetonitrile as solvent (entry 4 vs 5, 6, and 7) and collidine as
base (entry 4 vs 8 and 9) were preferable in this reaction. The
Carbohydrates are known to form complexes with transition
metals generally in water solutions.30–32 No doubt that nucleophi-
licity of hydroxyl groups involved in complexation will depend
both on the metal and on the geometry of the intermediate
complex.
benzoylation of methyl 2,3,4-tri-O-acetyl-a-D-glucopyranoside
and methyl 2,4-di-O-methyl-b- -xylopyranoside in these condi-
D
Recently we have found that selective substitution OH-3 in
glycopyranosides under acetylation33 and benzoylation34 is easily
achieved when molybdenum(V, VI) salts are used as catalysts, this
probably is determined by formation of an intermediate complex
of molybdenum atom with three hydroxyl groups of glycoside
molecule.33 Earlier Angyal35 has found that copper(II) ions form
strong complexes with some polyols at pH >5, presumably because
of formation of binuclear copper ions.
tions gave 45% and 12% of benzoates, respectively. This indicates
difficulty in substitution of isolated hydroxyl group especially at
secondary carbon atom.
High differences in the reactivity of secondary hydroxyl groups
of glycopyranosides in this reaction (Table 2) can be explained by
accepting the existence of an intermediate chelate of copper(II)
ion with cis-vicinal hydroxyl groups or with hydroxyl and methoxyl
groups (Scheme 1), in which only one hydroxyl group is predomi-
nantly ionized and the second hydroxyl group is coordinated with
copper(II) ion without ionization. The ionization of hydroxyl group
should essentially raise its nucleophilicity. Thus usually small
⇑
Tel.: +7 4232 311430; fax: +7 4232 314050.
E-mail address: evt@piboc.dvo.ru
0008-6215/$ - see front matter Ó 2012 Elsevier Ltd. All rights reserved.
http://dx.doi.org/10.1016/j.carres.2012.06.020

112
E. V. Evtushenko / Carbohydrate Research 359 (2012) 111–119
Table 1
Methyl
a
-
D
-fucopyranoside 4 (entry 4) has a configuration of
-arabinopyranoside 8, but it
Regioselective benzoylation of methyl a-L-rhamnopyranoside 1 by benzoic anhydride
hydroxyl groups similar to methyl b-
L
in the presence transition metal salts and 2,4,6-collidinea
also has the substitute at C-5, which evidently hinders attack of
the benzoylating agent, and does not contribute to stability of
O-4 anion, and as a result the content of 2-benzoate and 3-benzo-
ate in a reaction mixture was 80% and 9%, respectively. The latter
was probably formed owing to the reaction of a complex of Cu(II)
atom and O-3 and O-4 with benzoic anhydride (Scheme 4, a).
Entry Promoter
Solvent Parent
glycoside
Benzoatesb (%)
HO-2 HO-3 HO-4 Di- + Tri-
1
2
—
—
CH3CNc 92
CH3CN 66
2
4
6
26
10
2
3
4
3
3
6
3
4
3
2
1
3
2
1
3
5
6
3
2
2
4
3
2
3
4
Cu(CF3COO)2 CH3CNc 24
Cu(CF3COO)2 CH3CN
63
90
78
75
86
17
83
85
81
74
33
29
10
29
31
6
3
5
Methyl b-D-fucopyranoside 5 (entry 5) is likely to form only one
5
Cu(CF3COO)2 Dioxane 15
intermediate complex with involvement of O-3 and O-4 (Scheme 4,
b) and as a result, the content of 3-benzoate in reaction mixture
was 83% and 95% from monobenzoate fraction.
6
7
8
9
Cu(CF3COO)2 EtAc
Cu(CF3COO)2 THF
13
9
Cu(CF3COO)2 CH3CNd 75
4
4
3
7
6
5
6
Cu(CF3COO)2 CH3CNe
4
The benzoylation of methyl (1) and especially benzyl (2)
a-L-
10
11
12
13
14
15
16
17
Cu(TfO)2
Cu(ClO4)2
CH3CN
CH3CN
4
2
rhamnopyranoside (entries 1 and 2, respectively) in fact gave one
2-benzoate, possibly, due to the proximity of O-2 anion to the
anomeric center (Scheme 5, a and b). While the benzoylation of
b-anomer (3) (entry 3) gave almost exceptionally 3-benzoate,
92% from total mixture and 98% from monobenzoate fraction.
Probably, stereoelectronic factor plays a main role in this case,
destabilizing anion O-2 (Scheme 5, c). The interesting fact is that
the benzoylation of these anomers in the presence of MoO2(acac)2
as catalyst demonstrated inverse dependence.34
4
Cu(CCl3COO)2 CH3CN
Cu(BzO)2 CH3CN
Zn(CF3COO)2 CH3CN
Ni(CF3COO)2 CH3CN
Co(CF3COO)2 CH3CN
Gd(CF3COO)3 CH3CN
7
10
16
21
8
13
31
44
42
78
55
32
4
a
Reaction conditions: methyl
a-L-rhamnopyranoside (0.5 mmol), Bz2O
(0.65 mmol), promoter (0.65 mmol), base (0.65 mmol) in solvent (4 mL), 6 h, rt.
Determined by 1H NMR.
b
c
Acylation of methyl a-L-rhamnopyranoside 1 by anhydrides of
Reaction was executed without base.
Pyridine was used as base.
Triethylamine was used as base.
d
acetic, propionic and butyric acids (entries 23, 24, 25, respectively)
in these conditions gave similar results with larger selectivity for
butyric anhydride.
e
differences in the reactivity of hydroxyl groups of sugars in acyla-
tion reactions can become considerable ones after forming chelates
with copper(II) atoms.
Earlier8 it has been observed that the benzoylation of methyl
glycosides
method gave 6-benzoates, but the benzoylation of methyl glyco-
sides b- -galactose and -mannose led to mixtures of 3- and 6-
benzoates.
We have found that benzoylation of glycosides bearing free HO-
6, methyl - and b- -glucopyranosides 24 and 25 (entries 27 and
28, respectively), benzyl b- -glucopyranoside 26 (entry 30), benzyl
b- -galactopyranoside 27 (entry 32) and methyl 2-acetamido-2-
deoxy- -glucopyranoside 23 (entry 26) gave 6-benzoates with
a- and b-D-glucose and a-D-galactose using (Bu3Sn)2O
In general, both steric factors and factors, favoring the stabiliza-
tion of intermediate anions and increasing their nucleophilicity,
play an important role in the reactivity of the hydroxyl groups of
carbohydrates. They include, in particular, electron-withdrawing
adjacent groups, the adjacent methylene group, intermolecular
hydrogen bonding,36–38 and stereoelectronic effects.39 The com-
plexation of carbohydrates can change the ratio of these factors,
and as a consequence, the reactivity of the hydroxyl groups, that
seems interesting from a synthetic point of view.
D
a-D
a
D
D
D
a-D
average yield and full regioselectivity.
Benzoylation and butyration of methyl
a-D-glucopyranoside 24
As a result, methyl and benzyl b-
L
-arabinopyranosides 8 and 9
with 2.5 equiv of reagents gave 2,6-dibenzoate and 2,6-dibutyrate
with yields of 74% and 70%, respectively, (entries 33 and 34),
(Scheme 6). The similar result was received earlier18 at benzoyla-
(entries 8 and 9) having two couples of neighboring oxygen atoms,
O-3 and O-4 and O-2 and O-1 (Scheme 2, a) gave in this reaction 2-
and 4-benzoates in significant amounts. At the same time methyl
tion of methyl a-D-glucopyranoside using (Bu3Sn)2O method.
and benzyl
a
-L
-arabinopyranosides 6 and 7 (entries 6 and 7) having
It is known,9 that benzoylation in the presence of tributyltin
ethers and dialkylstannylene acetals of 6-O-protected glycosides
only one couple contiguous oxygen atoms, O-3 and O-4 (Scheme 2,
b) gave basically 4-benzoates.
The results of benzoylation of
the above-mentioned ones. While the benzoylation of
ranoside 11 (entry 11) has given an equal mixture of 2- and 4-ben-
zoates, the benzoylation of methyl (13) (entry 13) and benzyl (14)
(entry 14) b-D-xylopyranosides has demonstrated exceptionally
high regioselectivity in substitution of OH-4, which can be ex-
plained by the adjacency of the hydroxyl group to a methylene site
demonstrated replacement of O-3 for
glucose, but for the glycosides of -mannose high regioselectiv-
ity was not observed. We have found that the benzoylation of
methyl (17) and benzyl (18) glycosides of 6-O-trityl- -galacto-
pyranose (entries 17 and 18, respectively), methyl 6-O-trityl-
glucopyranoside (20) (entry 20) and methyl (21) and benzyl (22)
glycosides of 6-O-trityl- -mannopyranose (entries 21 and 22,
a-D-galactose, O-2 for a-D-
D
-xylopyranosides were similar to
-xylopy-
a-D
a
-D
a-D
a-D-
a-D
respectively) gave 2-benzoates with good yield and high
at C-5 (Scheme 3, a and b). Similar results of the benzoylation of
xylopyranosides and -arabinopyranosides with using organo tin
compounds were observed earlier.8,16,17
For better understanding the character of the interaction of cop-
per(II) ion with molecule of b- -xylopyranoside, methyl ethers of
this glycoside were used. Methyl 2-O-methyl-b- -xylopyranoside
15 (entry15) gave in this reaction practically one 2,4-di-O-methyl
b- -xylopyranoside confirming non participation of O-2 in the
D-
regioselectivity.
L
This result can be explained by the deprotonation of OH-2 in
intermediate copper(II) complex due to the proximity to the ano-
meric center with more electron-withdrawing capacity (Scheme
7). The benzoylation of methyl 6-O-trityl-b-
19 (entry 19) gave 3-benzoate with high yield and it was similar
to the result for methyl b- -fucopyranoside 5 (entry 5).
In conclusion, we have developed a simple and effective method
for regioselective protection of hydroxyl groups in glycopyrano-
sides. The regioselectivity is a consequence of formation of interme-
diate complexes of glycosides with copper(II) ions. The reaction of
the latter with benzoic anhydride leads to selective replacement.
As a consequence, replacement of OH-2 is reached for glycosides
D
D-galactopyranoside
D
D
D
complexation of the parent glycoside.
The benzoylation of methyl 3-O-methyl-b-D-xylopyranoside 16
(entry 16), however, gave approximately equal ratio of 2- and
4-benzoates, that is, possibly, determined by another type of an
intermediate complex of the glycoside with Cu(II) ion (Scheme 3,
c).
with the configurations of
a-Rha, a-Fuc, and 6-O-trityl ethers of

E. V. Evtushenko / Carbohydrate Research 359 (2012) 111–119
113
Table 2
Regioselective benzoylation of methyl and benzyl glycosides by benzoic anhydride in acetonitrile in the presence Cu(CF3COO)2 and 2,4,6-collidine
Entry
Glycoside
Benzoatesa (%)
HO-4
HO-2
HO-3
2
Di- + tri-
OMe
OBn
Me
HO
O
1
90 (83)
2
6
OH
1
OH
Me
HO
O
2
92 (84)
1
7
OH
2
OH
OH
Me
HO
OMe
O
3
4
92 (84)
2
6
OH
3
HO
Me
O
80 (70)
9
11
HO
OH
OMe
4
HO
Me
O
5
6
7
4
83 (72)
13
12
9
OMe
HO
HO
5
OH
O
8
6
80 (71)
85 (75)
OMe
HO
OH
OH
6
O
OBn
HO
HO
OH
7
O
8
9
43
28
3
42
52
12
HO
OH
OH
OMe
8
O
11
25
9
HO
HO
OH
9
OBn
O
OMe
10
11
52
45
13
45
10
OH
O
OH
10
HO
HO
HO
10
16
HO
HO
HO
OH
O
11
OMe
OMe
12
13
84 (73)
95 (86)
MeO
12
O
5
OMe
13
OH
(continued on next page)

114
E. V. Evtushenko / Carbohydrate Research 359 (2012) 111–119
Table 2 (continued)
Entry
Glycoside
Benzoatesa (%)
HO-4
HO-2
HO-3
Di- + tri-
2
O
HO
HO
14
15
16
98 (87)
96 (83)
43
OBn
OMe
OMe
14
15
16
OH
O
HO
HO
4
6
MeO
O
HO
51
MeO
OH
OH
OTr
OTr
O
17
18
81 (70)
6
4
13
HO
OH
OH
17
OMe
OBn
O
88 (78)
8
HO
OH
OH
18
OTr
O
19
20
4
86 (75)
10
10
OMe
HO
19
OH
OTr
O
HO
HO
85 (74)
5
OH
20
OMe
OTr
OH
O
HO
HO
21
85 (76)
6
9
21
22
OMe
OBn
OTr
OH
O
HO
HO
22
88 (77)
5
7
23
24
25
1+ Ac2O
80
75
85
11
14
13
1
2
8
9
2
1+ (EtCO)2O
1+ (PrCO)2O
Parent glycoside
Benzoatesa (%)
HO-2
HO-3
HO-4
HO-6
Di- + tri-
OH
O
HO
26
4
91 (83)
5
HO
AcNH
O
OMe
23
OH
HO
27
3
9
72 (65)
82 (72)
25
9
HO
HO
OMe
OMe
24
OH
O
HO
28
HO
25
OH
(continued on next page)

E. V. Evtushenko / Carbohydrate Research 359 (2012) 111–119
115
Table 2 (continued)
Parent glycoside
Benzoatesa (%)
HO-4 HO-6
HO-2
HO-3
Di- + tri-
15
OH
OH
OH
O
HO
29
10
6
75 (68)
77 (69)
77 (67)
OMe
OBn
OBn
HO
b
OH
O
25
HO
30
17
18
HO
OH
O
26
HO
31
5
HO
OH
26b
OH
OH
O
32
8
80 (70)
12
OBn
HO
27
OH
Benzoatesa (%)
HO-4
HO-2
HO-3
HO-6
2,6-di-Bz
87 (74)
OH
O
HO
33
13
16
HO
HO
OMe
24
OH
O
HO
34
84 (70)
HO
HO
24b
OMe
a
Determined by 1H NMR, isolated yields in brackets.
Butyrates.
b
~
~
Cu(TFA)2
collidine
~
~
~
~
~
~
Bz2O
C6H5
O-
-CuOBzTFA
HO
O-
HO
TFACu+
-TFA
OH
HO
HO
OBz
C=O
TFACu+
O
O=C
C6H5
Scheme 1. The proposed mechanism of regioselective benzoylation of diols in the presence of Cu(CF3COO)2.
a
-Glc,
a
-Gal, and
a
-Man; replacement of OH-3 for glycosides with
Chemical shifts (d) are reported in ppm related to Me4Si. (+)HR
LSI mass spectra were obtained on an Agilent Technology 6510
Q_TOF LC/MS mass spectrometer (USA). The samples were dis-
solved in methanol (c 0.01 mg/mL). TLC was performed on Silica
the configurations of b-Rha, b-Fuc, and b-Gal; replacement of OH-4
for glycosides with the configurations of b-Xyl and -Ara;
replacement of OH-6 for fully unprotected glycosides with the
configurations of -NAcGlc, -Glc, b-Glc, and b-Gal. The simple
a
a
a
Gel L (5–40 lm; Chemapol) with hexane–acetone 7:3 (A), and with
syntheses of the monobenzoates of some glycosides are offered.
CHCl3–MeOH 20:1 (B). For detection 10% sulfuric acid in ethanol at
130° was used. Column chromatography was performed on Silica
Gel (100–160
lm; Chemapol).
1. Experimental
1.2. General procedure for the monoacylation of glycosides 1–
1.1. General methods
27 and for the dibenzoylation and dibutyration of methyl
glucopyranoside 24
a-D-
Melting points were determined on Boethius micro hot-stage
apparatus and were uncorrected. Optical rotations were measured
with a Perkin–Elmer model 141. Spectra 1H and 13C NMR were reg-
istered on Bruker DPX-300 (1H at 300 MHz and 13C at 75 MHz).
The solution of glycopyranoside (0.5 mmol), anhydride
(0.65 mmol), promoter (0.65 mmol), and 2,4,6-collidine
(0.65 mmol) in a solvent (4 ml) was stirred at room temperature
a

116
E. V. Evtushenko / Carbohydrate Research 359 (2012) 111–119
O-
O-
1.6. Methyl 2-O-benzoyl-a-D-fucopyranoside (4a)
TFACu+
TFACu+
O
O
OMe
Yield from 4 99 mg, 70%. Rf 0.45 (A). mp 176–177 °C (from
O-
OH
HO
HO
OMe
EtOAc–hexane) ½a D20
ꢀ
+188.4 (c 0.4, CHCl3). 1H NMR (300 MHz,
CDCl3) d 8.11–8.08 (m, 2H, Ar), 7.61–7.51 (m, 1H, Ar), 7.49–7.43
(m, 2H, Ar), 5.20 (dd, 1H, J1,2 = 3.8 Hz, J2,3 = 10.1 Hz, H-2), 4.99 (d,
1H, H-1), 4.18 (ddd, 1H, J3,4 = 3.4 Hz, J3,OH-3 = 6.6 Hz, H-3), 4.06
(m, 1H, H-5), 3.88 (t, 1H, J4,5 = 3.4 Hz, H-4), 3.39 (s, 3H, OCH3),
2.84 (d, 1H, OH-3), 2.46 (d, 1H, J4,OH-4 = 4.6 Hz, OH-4), 1.35 (d,
3H, J5,CH3 = 6.7 Hz, CH3). 13C NMR (75 MHz, CDCl3) d 167.0, 133.3,
129.9, 129.5, 128.4, 97.5, 72.4, 72.3, 68.8, 65.4, 55.4, 16.1. HRMS
TFACu+
a
b
Scheme 2. The proposed coordination of methyl b- (a) and
a- (b)
L
-arabinopyr-
anosides by Cu+(CF3COO).
(ESI) calcd for
305.0998.
C
14H18O6Na m/z (M+Na)+: 305.0996. Found:
for 6 h. The dibenzoylation and the dibutyration of methyl
a-D-
glucopyranoside 24 were done with 2.5 equiv surplus of reagents.
The reaction was monitoring by TLC. For the treatment of mono-
benzoates of glycosides 1–22, 2,6-dibenzoate and 2,6-dibutyrate
of 24 chloroform (30 mL) was added to the reaction mixture. The or-
ganic layer was washed with 2 M HCl (2 mL), aq NaHCO3 (1 mL) and
water (1 mL) and was concentrated to small volume under reduced
pressure at room temperature. The products were isolated by flash
chromatography on a column of silica gel using gradient acetone
1.7. Methyl 3-O-benzoyl-b-D-fucopyranoside (5a)
Yield from 5 101 mg, 72%. The properties are as according to the
literature data.34
1.8. Methyl 4-O-benzoyl-a-L-arabinopyranoside (6a)
Yield from 6 95 mg, 71%. Rf 0.24 (A). ½a D20
ꢀ
+29.0 (c 0.7, CHCl3). 1H
in hexane. For the treatment of monobenzoates of methyl
a-L-
rhamnopyranoside 1, 6-monobenzoates and 6-monobutyrates of
glycosides 23–27 aq sodium thiosulfate (2 mmol) was added to
the reaction mixture until discoloration. The solution was concen-
trated to small volume under reduced pressure at room tempera-
ture. The products were isolated by flash chromatography on a
column of silica gel using gradient methanol in chloroform.
NMR (300 MHz, CDCl3) d 8.09–8.06 (m, 2H, Ar), 7.62–7.54 (m, 1H,
Ar), 7.47–7.42 (m, 2H, Ar), 5,39 (td, 1H, J3,4 = 3.5 Hz, J4,5a = 2.8 Hz,
J4,5b = 1.7 Hz, H-4), 4,23 (d, 1H, J1,2 = 6.8 Hz, H-1), 4.18 (dd, 1H,
J5a,5b = 13.2 Hz, H-5a), 3.92 (dd, 1H, J2,3 = 9.0 Hz, H-3), 3,83 (dd,
1H, H-2), 3,70 (dd, 1H, H-5b), 3,58 (s, 3H, CH3O). 13C NMR
(75 MHz, CDCl3) d 166.7, 133.2, 129.8, 129.6, 128.3, 103.9, 71.9,
71.6, 70.7, 63.7, 57.0. HRMS (ESI) calcd for C13H16O6Na m/z
(M+Na)+: 291.0839. Found: 291.0837.
1.3. Methyl 2-O-benzoyl-a-L-rhamnopyranoside (1a)
Yield from 1 117 mg, 83%. Rf 0.41 (A). ½a D20
ꢀ
+2.8 (c 0.6, CHCl3). 1H
1.9. Benzyl 4-O-benzoyl-a-L-arabinopyranoside (7a)
NMR (300 MHz, CDCl3) d 8.12–8.04 (m, 2H, Ar), 7.64–7.57 (m, 1H,
Ar), 7.49–7.43 (m, 2H, Ar), 5.34 (dd, 1H, J1,2 = 1.7 Hz, J2,3 = 3.5 Hz, H-
2), 4,78 (d, 1H, H-1), 4,06 (dd, 1H, J3,4 = 9.4 Hz, H-3), 3,74 (dd, 1H,
J5,6 = 6.1 Hz, H-5), 3,61 (t, 1H, J4,5 = 9.4 Hz, H-4), 3,42 (s, 3H,
OCH3), 1,39 (d, 3H, CH3). 13C NMR (75 MHz, CDCl3) d 166.3,
133.3, 129.8, 129.4, 128.3, 98.5, 73.5, 72.8, 70.5, 67.8, 54.9, 17.5.
HRMS (ESI) calcd for C14H18O6Na m/z (M+Na)+: 305.0996. Found:
305.1004.
Yield from 7 129 mg, 75%. Rf 0.33 (A). mp 137–138 °C (from
EtOAc–hexane), ½a D20
ꢀ
+8.4 (c 0.5, CHCl3). 1H NMR (300 MHz, CDCl3)
d 8.12–8.05 (m, 2H, Ar), 7.60–7.53 (m, 1H, Ar), 7.47–7.29 (m, 7H,
Ar), 5.38 (m, 1H, H-4), 4.95 (d, 1H, Jgem = 11.6 Hz, CH2Ph), 4.62 (d,
1H, CH2Ph), 4.40 (d, 1H, H-1), 4.20 (dd, 1H, J4,5a = 2.8 Hz,
J5a,5b = 13.2 Hz, H-5a), 3.89 (m, 2H, H-2, H-3), 3.69 (dd, 1H,
J4,5b = 1.5 Hz, H-5b). 13C NMR (75 MHz, CDCl3) d 166.2, 136.7,
133.2, 129.8, 128.5, 128.3, 128.2, 128.1, 101.8, 72.0, 71.6, 71.0,
70.5, 63.7. HRMS (ESI) calcd for
367.1152. Found: 367.1151.
C
19H20O6Na m/z (M+Na)+:
1.4. Benzyl 2-O-benzoyl-a-L-rhamnopyranoside (2a)
Yield from 2 150 mg, 84%. Rf 0.52 (A). mp 126–127 °C (from
EtOAc–hexane) ½a D20
ꢀ
ꢁ53.5 (c 0.6, CHCl3). 1H NMR (300 MHz,
1.10. Methyl 4-O-benzoyl-2-O-methyl-a-D-xylopyranoside (12a)
CDCl3) d 8.09–8.04 (m, 2H, Ar), 7.64–7.57 (m, 1H, Ar), 7.47–7.30
(m, 7H, Ar), 5.42 (dd, 1H, J1,2 = 1.6 Hz, J2,3 = 3.5 Hz, H-2), 5.01 (d,
1H, H-1), 4.78 (d, 1H, Jgem = 11.8 Hz, CH2Ph), 4.58 (d, 1H, CH2Ph),
4.15 (dd, 1H, J3,4 = 9.4 Hz, H-3), 3.84 (dd, 1H, J4,5 = 9.4 Hz,
J5,6 = 6.1 Hz, H-5), 3.65 (t, 1H, H-4), 1.39 (d, 3H, CH3). 13C NMR
(75 MHz, CDCl3) d 166.3, 136.9, 133.4, 129.8, 129.3, 128.4, 128.3,
127.9, 96.9, 73.6, 72.9, 70.6, 69.4, 68.2, 17.5. HRMS (ESI) calcd for
Yield from 12 103 mg, 73%. Rf 0.47 (A). mp 107–108 °C (from
EtOAc–hexane) ½a D20
ꢀ
+71.3 (c 0.4, CHCl3). 1H NMR (300 MHz, CDCl3)
d 8.08–8.04 (m, 2H, Ar), 7.61–7.54 (m, 1H, Ar), 7.48–7.41 (m, 2H,
Ar), 5.10 (m, 1H, H-4), 4.91 (d, 1H, J1,2 = 3.4 Hz, H-1), 4.15 (t, 1H,
J2,3 = 9.4 Hz, J3,4 = 9.4 Hz, H-3), 3.89 (dd, 1H, J4,5a = 5.9 Hz,
J5a,5b = 10.8 Hz, H-5a), 3.61 (t, J4,5b = 10.8 Hz, H-5b), 3.55 (s, 3H,
OCH3), 3.46 (s, 3H, OCH3), 3.30 (dd, 1H, H-2). 13C NMR (75 MHz,
CDCl3) d 166.1, 133.3, 129.8, 129.5, 128.4, 96.9, 81.4, 71.9, 70.7,
58.7, 58.4, 55.5. HRMS (ESI) calcd for C14H18O6Na m/z (M+Na)+:
305.0996. Found: 305.0992.
C
20H22O6Na m/z (M+Na)+: 381.1309. Found: 381.1305.
1.5. Methyl 3-O-benzoyl-b- -rhamnopyranoside (3a)
L
Yield from 3 118 mg, 84%. Rf 0.48 (A). mp 104–105 °C (from
EtOAc–hexane) ½a D20
ꢀ
+92.0 (c 0.5, CHCl3). 1H NMR (300 MHz, CDCl3)
1.11. Methyl 4-O-benzoyl-b-D-xylopyranoside (13a)
d 8.12–8.08 (m, 2H, Ar), 7.62–7.55 (m, 1H, Ar), 7.47–7.40 (m, 2H,
Ar), 4.98 (dd, 1H, J2,3 = 3.0 Hz, J3,4 = 9.7 Hz, H-3), 4.50 (d, 1H,
J1,2 = 1.0 Hz, H-1), 4.23 (dd, 1H, H-2), 3.87 (t, 1H, J4,5 = 9.5 Hz, H-
4), 3.56 (s, 3H, OCH3), 3.43 (dd, 1H, J5,6 = 6.1 Hz, H-5), 1.41 (d, 3H,
CH3). 13C NMR (75 MHz, CDCl3) d 166.7, 133.3, 129.8, 129.4,
128.4, 100.2, 76.6, 72.2, 70.5, 69.4, 56.8, 17.5. HRMS (ESI) calcd
for C14H18O6Na m/z (M+Na)+: 305.0996. Found: 305.1001.
Yield from 13 115 mg, 86%. Rf 0.30 (A). mp 118–119 °C (from
EtOAc–hexane) ½a D20
ꢀ
ꢁ101.8 (c 0.4, CHCl3). Lit. data:8 mp 125–
126 °C. Lit. data:16 mp 84–85 °C, ½a D20
ꢀ
ꢁ81.4 (CHCl3). Lit. data:17
mp 122.5–123.5 °C, ½a D
ꢀ
ꢁ92.3 (CH2Cl2). 1H NMR (300 MHz, CDCl3)
d 8.08–8.02, (m, 2H, Ar), 7.62–7.56 (m, 1H, Ar), 7.48–7.43 (m, 2H,
Ar), 5.09 (td, 1H, J3,4 = 7.4 Hz, J4,5a = 4.5 Hz, J4,5b = 7.4 Hz, H-4),

E. V. Evtushenko / Carbohydrate Research 359 (2012) 111–119
117
OMe
OMe
O
O
O
O-
OH
O-
OH
OMe
O-
-O
O-
OH
TFACu+
TFACu+
OMe
TFACu+
TFACu+
a
b
c
Scheme 3. The proposed coordination of methyl
a
- (a), b- (b) and 3-O-methyl b- (c)
D
-xylopyranosides by Cu+(CF3COO).
(ESI) calcd for
305.0993.
C
14H18O6Na m/z (M+Na)+: 305.0996. Found:
OH
Me
TFACu+
Me
O
OH
TFACu+
O
O-
O-
OMe
O-
OMe
HO
1.14. Methyl 2-O-benzoyl-6-O-trityl-a-D-galactopyranoside (17a)
TFACu+
Yield from 17 189 mg, 70%. Rf 0.48 (A). mp 144–146 °C (from
a
b
EtOAc–hexane) ½a D20
ꢀ
+90.0 (c 0.4, CHCl3). 1H NMR (300 MHz, CDCl3)
d 8.15–8.10 (m, 2H, Ar), 7.87–7.83 (m, 1H, Ar), 7.64–7.47 (m, 9H,
Ar), 7.39–7.28 (m, 8H, Ar), 5,28 (dd, 1H, J1,2 = 3.8 Hz, J2,3 = 9.8 Hz,
H-2), 5,09 (d, 1H, H-1), 4.28–4.12 (m, 2H, H-3, H-4), 3,97 (bt, 1H,
J5,6 = 5.8 Hz, H-5), 3.54–3.46 (m, 2H, H-6a, H-6b), 3,44 (s, 3H,
OCH3), 2.79 (d, 1H, JH,OH = 3.2 Hz, OH), 2.76 (d, 1H, JH,OH = 7.7 Hz,
OH). 13C NMR (75 MHz, CDCl3) d 166.9, 143.6, 133.2, 132.0,
129.9, 129.6, 128.5, 128.3, 127.9, 127.3, 127.1, 97.5, 72.3, 70.3,
Scheme 4. The proposed coordination of methyl
a- (a) and b- (b) D-fucopyrano-
sides by Cu+(CF3COO).
4.40 (d, 1H, J1,2 = 5.9 Hz, H-1), 4.23 (dd, 1H, J5a,5b = 12.1 Hz, H-5a),
3,91 (dt, 1H, J2,3 = 7.4 Hz, J3,OH-3 = 3.9 Hz, H-3), 3.63–3.49 (m, 2H,
H-2, H-5b), 3.56 (s, 3H, OCH3). 13C NMR (75 MHz, CDCl3) d 165.9,
133.4, 129.7, 129.3, 128.4, 103.4, 72.7, 72.5, 71.8, 61.7, 56.8. HRMS
(ESI) calcd for
291.0843.
C
13H16O6Na m/z (M+Na)+: 291.0839. Found:
68.5 ꢂ 2, 63.3, 55.3. HRMS (ESI) calcd for
C33H32O7Na m/z
(M+Na)+: 563.2040. Found: 563.2036.
1.12. Benzyl 4-O-benzoyl-b-D-xylopyranoside (14a)
1.15. Benzyl 2-O-benzoyl-6-O-trityl-a-D-galactopyranoside (18a)
Yield from 14 150 mg, 87%. Rf 0.44 (A). mp 142–143 °C (from
Yield from 18 240 mg, 78%. Rf 0.46 (A). mp 67–68 °C (from
EtOAc–hexane) ½a D20
ꢀ
ꢁ53.6 (c 0.5, CHCl3). 1H NMR (300 MHz,
EtOAc–hexane) ½a D20
ꢀ
+94.8 (c 0.6, CHCl3). 1H NMR (300 MHz, CDCl3)
CDCl3) d 8.05–8.02 (m, 2H, Ar), 7.63–7.56 (m, 1H, Ar), 7.49–7.30
(m, 7H, Ar), 5.11 (dt, 1H, J3,4 = 7.3 Hz, J4,5a = 4.4 Hz, J4,5b = 7.3 Hz,
H-4), 4.91 (d, 1H, Jgem = 11.6 Hz, CH2Ph), 4.64 (d, 1H, CH2Ph), 4.58
(d, 1H, J1,2 = 5.8 Hz, H-1), 4.26 (dd, 1H, J5a,5b = 12.2 Hz, H-5a), 3.90
(dt, 1H, J2,3 = 7.4 Hz, H-3), 3.64 (dt, 1H, H-2), 3.55 (dd, 1H, H-5b),
3.10, (d, 1H, JOH,H = 5.3 Hz, OH), 2.72 (d, 1H, JOH,H = 5.1 Hz, OH)
13C NMR (75 MHz, CDCl3) d 166.1, 133.2, 132.8, 129.6, 128.3,
128.2, 128.1, 128.0, 127.9, 102.0, 73.1 ꢂ 2, 71.9, 70.8, 62.4. HRMS
d 8.12–8.06 (m, 2H, Ar), 7.64–7.56 (m, 1H, Ar), 7.52–7.44 (m, 8H,
Ar), 7.37–7.24 (m, 14H, Ar), 5,28 (dd, 1H, J1,2 = 3.8 Hz,
J2,3 = 10.0 Hz, H-2), 5,23 (d, 1H, H-1), 4,77 (d, 1H, Jgem = 12.3 Hz,
CH2Ph), 4,57 (d, 1H, CH2Ph), 4,19 (m, 1H, H-3), 4,11 (m, 1H, H-4),
4,03 (td, 1H, J4,5 = 1.0 Hz, J5,6a = 5.7, J5,6b = 5.7 Hz, H-5), 3,46 (dd,
1H, J6a,6b = 9.9 Hz, H-6a), 3,39 (dd, 1H, H-6b), 2.77 (dd, 1H,
JH,OH = 3.3 Hz, OH) 2.73 (dd, 1H, JH,OH = 7.8 Hz, OH). 13C NMR
(75 MHz, CDCl3) d 166.8, 143.6, 137.2, 133.2, 129.8, 129.6, 128.6,
128.3, 127.9, 127.7, 127.5, 127.1, 95.7, 72.3, 70.3, 69.4, 69.0, 68.6,
63.4. HRMS (ESI) calcd for C39H36O7Na m/z (M+Na)+: 639.2353.
Found: 639.2358.
(ESI) calcd for
367.1150.
C
19H20O6Na m/z (M+Na)+: 367.1152. Found:
1.13. Methyl 4-O-benzoyl-2-O-methyl-b-D-xylopyranoside (15a)
1.16. Methyl 3-O-benzoyl-6-O-trityl-b-D-galactopyranoside (19a)
Yield from 15 117 mg, 83%. Rf 0.52 (A). mp 135–136 °C (from
EtOAc–hexane) ½a D20
ꢀ
ꢁ133.8 (c 0.4, CHCl3). 1H NMR (300 MHz,
Yield from 19 202 mg, 75%. The properties are as according to
the literature data.34
CDCl3) d 8.09–8.04 (m, 2H, Ar), 7.61–7.54 (m, 1H, Ar), 7.48–7.41
(m, 2H, Ar), 5,08 (td, 1H, J3,4 = 7.9 Hz, J4,5a = 4.8 Hz, J4,5b = 7.9 Hz,
H-4), 4,40 (d, 1H, J1,2 = 6.1 Hz, H-1), 4,21 (dd, 1H, J5a,5b = 12.0 Hz,
H-5a), 3,89 (td, 1H, J2,3 = 7.9 Hz, J3,OH-3 = 3.0 Hz, H-3), 3,59 (s, 3H,
OCH3), 3,54 (s, 3H, OCH3), 3,47 (dd, 1H, H-5b), 3,16 (dd, 1H, H-2),
2,97 (d, 1H, OH-3). 13C NMR (75 MHz, CDCl3) d 166.0, 133.2,
129.7, 129.5, 128.3, 103.5, 81.5, 71.7 ꢂ 2, 61.6, 60.0, 56.4. HRMS
1.17. Methyl 2-O-benzoyl-6-O-trityl-a-D-glucopyranoside (20a)
Yield from 20 200 mg, 74%. Rf 0.46 (A). mp 83–85 °C (from
EtOAc–hexane), ½a D20
ꢀ
+70.1 (c 0.4, CHCl3). Lit data:40 85–86 °C. 1H
NMR (300 MHz, CDCl3) d 8.11–8.08 (m, 2H, PhH), 7.60–7.54 (m,
OMe
OMe
Me
Me
HO
OMe
O
Me
HO
O
O
HO
Cu+TFA
O-
OH
HO
-O
HO
O-
TFACu+
TFACu+
a
b
c
Scheme 5. The proposed coordination of methyl a- I type (a), a- II type (b) and b- (c) L
-rhamnopyranosides by Cu+(CF3COO).

118
E. V. Evtushenko / Carbohydrate Research 359 (2012) 111–119
Cu+TFA
CD3OD) d 8,08–8,00 (m, 2H, Ar), 7,63–7,57 (m, 1H, Ar), 7,50–7,44
Cu+TFA
OMe
-O
-O
(m, 2H, Ar), 4,67 (d, 1H, J1,2 = 3.6 Hz, H-1), 4,64 (dd, 1H,
J5,6a = 2.1 Hz, J6a,6b = 11.8 Hz, H-6a), 4,45 (dd, 1H, J5,6b = 5.8 Hz, H-
6b), 4.02 (dd, 1H, J2,3 = 10.6 Hz, H-2), 3.86 (ddd, 1H, J4,5 = 9.9 Hz,
H-5), 3,67 (dd, 1H, J3,4 = 8.9 Hz, H-3), 3.48 (t, 1H, H-4), 3.37
(s, 3H, OCH3), 1.98 (s, 3H, CH3CO). 13C NMR (75 MHz, CD3OD) d
174.3, 168.5, 134.9, 132.0, 131.1, 130.2, 100.5, 73.5, 73.0, 71.9,
65.9, 56.1, 55.9, 23.2. HRMS (ESI) calcd for C16H21O7NNa m/z
(M+Na)+: 362.1210. Found: 362.1205.
O
HO
HO
O
HO
HO
O-
HO
OMe
TFACu+
a
b
Scheme 6. The proposed coordination of methyl
COO), (a)—with 1.3 equiv, (b)—with 2.5 equiv of promoter.
a-
D
-glucopyranoside by Cu+(CF3-
1.21. Methyl 6-O-benzoyl-a-D-glucopyranoside (24a)
1H, PhH), 7.50–7.44 (m,7H, PhH), 7.35–7.22 (m, 10H, PhH), 5.03 (d,
1H, J1,2 3.7 Hz, H-1), 4.95 (dd, 1H, J2,3 9.9 Hz, H-2), 4.10 (t, 1H, J3,4
8.6 Hz, H-3), 3.74 (m, 1H, H-5), 3.66 (dd, 1H, J4.5 9.6 Hz, H-4),
3,49–3.42 (m, 2H, H-6a, H-6b), 3.38 (s, 3H, OCH3). 13C NMR
(75 MHz, CDCl3) d 166.6, 143.6, 133.4, 133.2, 129.9, 128.6, 128.3,
127.6, 127.1, 97.0, 73.7, 72.4, 71.7, 69.5, 63.9, 55.1. HRMS (ESI)
calcd for C33H32O7Na m/z (M+Na)+: 563.2040. Found: 563.2038.
Yield from 24 97 mg, 65%. Rf 0.21 (B). mp 126–128 °C (from
EtOAc–hexane), ½a D20
ꢀ
+92.7 (c 0.5, CHCl3). Lit. data:41 mp 127–
+91.0 (CHCl3). 1H NMR (300 MHz, CD3OD)
129 °C, Lit. data:18
½aꢀD
d 8.09–8.04 (m, 2H, Ar), 7.67–7.62 (m, 1H, Ar), 7.55–7.48 (m, 2H,
Ar), 4.72 (d, 1H, J1,2 = 3.7 Hz, H-1), 4.66 (dd, 1H, J5,6a = 2.1 Hz,
J6a,6b = 11.8 Hz, H-6a), 4.47 (dd, 1H, J5,6b = 6.0 Hz, H-6b), 3.88
(ddd, 1H, J4,5 = 9.8 Hz, H-5), 3.69 (t, 1H, J2,3 = J3,4 9.3 Hz, H-3),
3.47–3.37 (m, 2H, H-2, H-4), 3.44 (s, 3H, OCH3). 13C NMR
(75 MHz, CD3OD) d 168.5, 134.9 132.0, 131.1, 130.2, 101.9, 75.7,
74.1, 72.6, 71.8, 66.0, 56.2. HRMS (ESI) calcd for C14H18O7Na m/z
(M+Na)+: 321.0945. Found: 321.0949.
1.18. Methyl 2-O-benzoyl-6-O-trityl-a-D-mannopyranoside
(21a)
Yield from 21 205 mg, 76%. Rf 0.43 (A). mp 74–76 °C (from
EtOAc–hexane) ½a D20
ꢀ
+11.1 (c 0.5, CHCl3). 1H NMR (300 MHz, CDCl3)
d 8.10–8.06 (m, 2H, Ar), 7.63–7.43 (m, 9H, Ar), 7.35–7.27 (m, 9H,
Ar), 5,36 (dd, 1H, J1,2 = 1.7 Hz, J2,3 = 2.8 Hz, H-2), 4,86 (d, 1H, H-1),
4,10–3.98 (m, 2H, H-3, H-4), 3,68 (m, 1H, H-5), 3,54 (dd,
J5,6a = 3.9 Hz, J6a,6b = 10.2 Hz, H-6a), 3,46 (dd, 1H, J5,6b = 4.5 Hz,
H-6b), 3,40 (s, 3H, OCH3), 2.38 (d, 1H, JH,OH = 2.6 Hz, OH), 2.28
(d, 1H, JH,OH = 4.7 Hz, OH). 13C NMR (75 MHz, CDCl3) d 166.2,
143.7, 133.3, 129.8, 129.5, 128.6, 128.4, 127.8, 127.0, 98.6, 72.3,
70.6, 70.2, 69.4, 63.5, 55.0. HRMS (ESI) calcd for C33H32O7Na m/z
(M+Na)+: 563.2040. Found: 563.2045.
1.22. Methyl 6-O-benzoyl-b-D-glucopyranoside (25a)
Yield from 25 107 mg, 72%. Rf 0.19 (B). mp 132–133 °C (from
EtOAc–hexane), ½a D20
ꢀ
ꢁ18.5 (c 0.5, CHCl3). Lit. data:8 mp 136–
138 °C. Lit. data:41 mp 131–132 °C, ½a 2D7
ꢀ
ꢁ24.2 (water). 1H NMR
(300 MHz, CD3OD) d 8.10–8.06 (m, 2H, Ar), 7.67–7.62 (m, 1H, Ar),
7.55–7.49 (m, 2H, Ar), 4.69 (dd, 1H, J5,6a = 2.2 Hz, J6a,6b = 11.9 Hz,
H-6a), 4.49 (dd, 1H, J5,6b = 5.7 Hz, H-6b), 4.26 (d, 1H, J1,2 = 7.8 Hz,
H-1), 3.63 (ddd, 1H, J4,5 = 9.5 Hz, H-5), 3.52 (s, 3H, OMe), 3.45 (m,
2H, H-3, H-4), 3.24 (dd, 1H, J2,3 = 8.9, H-2). 13C NMR (75 MHz,
CD3OD) d 168.5, 134.9, 132.0, 131.2, 130.2, 106.0, 78.5, 76.0, 75.6,
72.4, 65.8, 57.8. HRMS (ESI) calcd for C14H18O7Na m/z (M+Na)+:
321.0945. Found: 321.0942.
1.19. Benzyl 2-O-benzoyl-6-O-trityl-a-D-mannopyranoside (22a)
Yield from 22 237 mg, 77%. Rf 0.37 (A). mp 62–64 °C (from
EtOAc–hexane) ½a D20
ꢀ
+21.4 (c 0.4, CHCl3). 1H NMR (300 MHz, CDCl3)
d 8.10–8.05 (m, 2H, Ar), 7.83–7.79 (m, 1H, Ar), 7.60–7.40 (m, 10H,
Ar), 7.36–7.27 (m, 12H, Ar) 5.43 (dd, 1H, J1,2 = 1.7 Hz, J2,3 = 3.3 Hz,
H-2), 5.07 (d, 1H, H-1), 4.76 and 4.56 (2d, 2H, Jgem = 11.8 Hz,
CH2Ph), 4.15 (m, 1H, H-3), 4.05 (t, 1H, J3,4 = 9.4 Hz, J4,5 = 9.4 Hz,
H-4), 3.78 (m, 1H, H-5), 3.52 (dd, 1H, J5,6a = 3.8 Hz, J6a,6b = 10.1
Hz, H-6a), 3,44 (dd, 1H, J5,6b = 4.6 Hz, H-6b), 2.39 (d, 1H,
JH,OH = 2.2 Hz, OH), 2.34 (d, 1H, JH,OH = 3.9 Hz, OH). 13C NMR
(75 MHz, CDCl3) d 166.2, 143.8, 136.9, 133.2, 131.9, 129.8, 129.6,
128.6, 128.5, 128.4, 127.8, 127.3, 127.0, 96.9, 72.4, 71.2, 70.4,
69.3, 69.2, 63.4. HRMS (ESI) calcd for C39H36O7Na m/z (M+Na)+:
639.2353. Found: 639.2357.
1.23. Methyl 6-O-butyryl-b-D-glucopyranoside (25b)
Yield from 25 90 mg, 68%. Rf 0.21 (B). mp 104–106 °C (from
EtOAc–hexane), ½a D20
ꢀ
ꢁ20.4 (c 0.4, CHCl3). 1H NMR (300 MHz,
CD3OD) d 4.45 (dd, 1H, J5,6a = 2.1 Hz, J6a,6b = 11.8 Hz, H-6a), 4.24
(dd, 1H, J5,6b = 5.8 Hz, H-6b), 4.20 (d, 1H, J1,2 = 7.8 Hz, H-1), 3.52 (s,
3H, OCH3), 3.50–3.37 (m, 2H), 3.30 (m, 1H), 3.14 (t, 1H, J = 8.4 Hz),
2.37 (t, 2H, J = 7.3 Hz, CH2CO), 1.68 (dt, 2H, J = 7.2 Hz, CH2CH3),
0.99 (t, 3H, J = 7.4 Hz, CH3). 13C NMR (75 MHz, CD3OD) d 175.8,
106.0, 78.5, 75.9, 75.6, 72.2, 65.1, 57.8, 37.4, 20.0, 14.5. HRMS (ESI)
calcd for C11H20O7Na m/z (M+Na)+: 287.1101. Found: 287.1096.
1.20. Methyl 6-O-benzoyl-2-acetamido-2-deoxy-a-D-
glucopyranoside (23a)
1.24. Benzyl 6-O-benzoyl-b-D-glucopyranoside (26a)
Yield from 26 129 mg, 69%. Rf 0.33 (B). mp 118–119 °C (from
Yield from 23 141 mg, 83%. Rf 0.17 (B). mp 194–195 °C (from
EtOAc–hexane), ½a D20
ꢀ
ꢁ51.2 (c 0.7, CHCl3). 1H NMR (300 MHz,
EtOAc–hexane) ½a D20
ꢀ
+44.0 (c 0.6, CHCl3). 1H NMR (300 MHz,
Cu+TFA
TrO
TrO
-O
OTr
HO
OTr
O-
O
O
O
O
HO
HO
HO
HO
HO
HO
HO
O-
O-
OMe
OMe
OMe
OMe
TFACu+
TFACu+
TFACu+
a
b
c
d
Scheme 7. The proposed coordination of 6-O-trityl ethers of methyl
methyl
-mannopyranoside, II type (d) by Cu+(CF3COO).
a-D-glucopyranoside (a), methyl a-D-galactopyranoside (b), methyl a-D-mannopyranoside, I type (c) and
a-D

E. V. Evtushenko / Carbohydrate Research 359 (2012) 111–119
119
CD3OD) d 8.08–8.04 (m, 2H, Ar), 7.65–7.58 (m, 1H, Ar), 7.52–7.45
(m, 2H, Ar), 7.35–7.22 (m, 5H, Ar), 4.80 (d, 1H, Jgem = 11.9 Hz,
CH2), 4.67 (dd, 1H, J5,6a = 2.1 Hz, J6a,6b = 11.8 Hz, H-6a), 4.62
(d, 1H, CH2), 4.48 (dd, 1H, J5,6b = 6.1, H-6b), 4.37 (d, 1H,
J1,2 = 7.7 Hz, H-1), 3.57 (ddd, 1H, J4,5 = 9.4 Hz, H-5), 3.43 (t, 1H,
J = 8.5 Hz), 3.37 (t, 1H, J = 8.5 Hz), 3.27 (m, 1H). 13C NMR
(75 MHz, CD3OD) d 168.5, 139.3, 135.0, 132.0, 131.2, 130.2,
129.9, 129.8, 129.3, 103.7, 78.6, 76.0, 75.7, 72.5, 72.4, 65.8. HRMS
1H, J2,3 = 10.0 Hz, H-2), 4.49 (dd, 1H, J5,6a = 4.4 Hz, J6a,6b = 12.2 Hz,
H-6a), 4.26 (dd, 1H, J5,6b = 2.0 Hz, H-6b), 3.95 (t, 1H, J3,4 = 9.4 Hz,),
3.75 (ddd, 1H, J4,5 = 10.0, H-5), 3.42 (m, 1H), 3.36 (s, 3H, OCH3),
2.36 (m, 4H, CH2CO), 1.66 (m, 4H, CH2CH3), 0.95 (m, 6H, CH3). 13C
NMR (75 MHz, CDCl3) d 174.5, 173.5, 97.1, 72.8, 71.2, 70.4, 69.3,
62.8, 55.2, 35.9 ꢂ 2, 18.3 ꢂ 2, 13.5, 13.4. HRMS (ESI) calcd for
C
15H26O8Na m/z (M+Na)+: 357.1520. Found: 357.1523.
(ESI) calcd for
397.1252.
C
20H22O7Na m/z (M+Na)+: 397.1258. Found:
Supplementary data
Supplementary data associated with this article can be found,
in the online version, at http://dx.doi.org/10.1016/j.carres.2012.
06.020.
1.25. Benzyl 6-O-butyryl-b-D-glucopyranoside (26b)
Yield from 26 114 mg, 67%. Rf 0.36 (B). mp 54–56 °C (from
EtOAc–hexane) ½a D20
ꢀ
ꢁ56.7 (c 0.4, CHCl3). Lit. data:42 mp 65 °C
½
a 2D3
ꢀ
ꢁ55.7° (CHCl3). 1H NMR (300 MHz, CD3OD) d 7.50–7.25 (m,
References
5H, Ar), 4.63(d, 1H, Jgem = 11.8 Hz, CH2), 4.44 (dd, 1H,
J5,6a = 2.0 Hz, J6a,6b = 11.8 Hz, H-6a), 4.34 (d, 1H, J1,2 = 7.6 Hz, H-2),
4.22 (dd, 1H, J5,6b = 5.8 Hz, H-6b), 3.44 (ddd, 1H, J4,5 = 9.1 Hz, H-
5), 3.35–3.30 (m, 2H), 3.24 (dd, 1H, J2,3 = 9.3 Hz, H-3), 2.35 (t, 2H,
J = 7.2 Hz, CH2CO), 1.66 (dt, 2H, J = 7.4 Hz, CH2CH3), 0.96 (t, 3H,
J = 7.4 Hz, CH3). 13C NMR (75 MHz, CD3OD) d 175.8, 139.5, 129.9,
129.8, 129.3. 103.8, 78.5, 76.0, 75.6, 72.4, 72.3, 65.1, 37.5, 20.0,
14.6. HRMS (ESI) calcd for C17H24O7Na m/z (M+Na)+: 363.1414.
Found: 363.1419.
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94 °C ½a 2D5
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ꢁ22.5 (methanol). 1H NMR (300 MHz, CD3OD) d 8.07–
7.99 (m, 2H, Ar), 7.63–7.54 (m, 1H, Ar), 7.52–7.45 (m, 2H, Ar),
7.37–7.22 (m, 5H, Ar), 4.82 (d, 1H, PhCH2), 4.64 (d, 1H,
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129.8, 129.3, 104.1, 75.3, 74.7, 73.0, 72.2, 71.0, 65.8. HRMS (ESI)
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1.27. Methyl 2,6-di-O-benzoyl-a-D-glucopyranoside (24b)
Yield from 24 149 mg, 74%. Rf 0.41 (A). mp 142–143 °C (from
EtOAc–hexane) ½a D20
ꢀ
+70.4 (c 0.6, CHCl3). Lit. data:18 mp 140–
142 °C, ½a D
ꢀ
+66.1 (CHCl3). 1H NMR (300 MHz, CDCl3) d 8.11–8.07
(m, 4H, Ar), 7.63–7.55 (m, 2H, Ar), 7.49–7.43 (m, 4H, Ar), 5.06 (d,
1H, J1,2 = 3.7 Hz, H-1), 4.95 (dd, 1H, J2,3 = 10.0 Hz, H-2), 4.83 (dd,
1H, J5,6a = 4.2 Hz, J6a,6b = 12.3 Hz, H-6a), 4.52 (dd, 1H, J5,6b = 2.2 Hz,
H-6b), 4.19 (dt, 1H, J = 9.5 Hz), 3.95 (ddd, 1H, J4,5 = 10.0 Hz, H-5),
3.59 (dt, 1H, J = 9.6 Hz), 3.41 (s, 3H, OCH3), 3.32 (d, 1H,
JH,OH = 3.4 Hz, OH), 2.71 (d, 1H, JH,OH = 3.2 Hz, OH). 13C NMR
(75 MHz, CDCl3) d 167.2, 166.4, 133.3, 133.0, 129.9, 129.8, 129.5,
129.4, 128.4, 128.3, 97.3, 73.7, 71.5, 70.6, 69.5, 63.6, 55.3. HRMS
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(ESI) calcd for
425.1211.
C
21H22O8Na m/z (M+Na)+: 425.1207. Found:
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1.28. Methyl 2,6-di-O-butyryl-a-D-glucopyranoside (24c)
Yield from 24 117 mg, 70%. Rf 0.56 (A). ½a D20
ꢀ
+84.5 (c 0.6, CHCl3).
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1H NMR (300 MHz, CDCl3) d 4.89 (d, 1H, J1,2 = 3.6 Hz, H-1), 4.69 (dd,