Matched and mismatched acceptor/donor pairs in the glycosylation of a trisaccharide diol free at O-3 of two N-acylated glucosamine residues

Article abstract of DOI:10.1016/j.carres.2012.04.020

Reciprocal donor acceptor selectivity (RDAS) and double diastereodifferentiation are two concepts that have been used to explain how a glycosyl acceptor and donor may be 'matched' or 'mismatched' in glycosylation reactions. We describe here how the α-l-fucosylation and β-d-galactosylation of a trisaccharide displaying two equatorial OH groups at C-3 of N-acylated glucosamine units led to different regioselectivities or different 'matched' pairs. These results may be explained under the reciprocal donor acceptor selectivity or double diastereodifferentiation concepts. We also suggest a third explanation to these results: the presence of a benzylidene at the nonreducing end acceptor led to rigidity at this residue which resulted into a mismatched pair during β-d-galactosylation but allowed α-l-fucosylation.

Full text of DOI:10.1016/j.carres.2012.04.020

Carbohydrate Research 357 (2012) 132–138
Contents lists available at SciVerse ScienceDirect
Carbohydrate Research
journal homepage: www.elsevier.com/locate/carres
Note
Matched and mismatched acceptor/donor pairs in the glycosylation of a
trisaccharide diol free at O-3 of two N-acylated glucosamine residues
⇑
Mickael Guillemineau, France-Isabelle Auzanneau
Department of Chemistry, University of Guelph, Guelph, Ontario, Canada N1G 2W1
a r t i c l e i n f o
a b s t r a c t
Article history:
Received 7 March 2012
Received in revised form 25 April 2012
Accepted 30 April 2012
Available online 26 May 2012
Reciprocal donor acceptor selectivity (RDAS) and double diastereodifferentiation are two concepts that
have been used to explain how a glycosyl acceptor and donor may be ‘matched’ or ‘mismatched’ in gly-
cosylation reactions. We describe here how the
a-L-fucosylation and b-D-galactosylation of a trisaccha-
ride displaying two equatorial OH groups at C-3 of N-acylated glucosamine units led to different
regioselectivities or different ‘matched’ pairs. These results may be explained under the reciprocal donor
acceptor selectivity or double diastereodifferentiation concepts. We also suggest a third explanation to
these results: the presence of a benzylidene at the nonreducing end acceptor led to rigidity at this residue
This paper is dedicated to Dr. Malcolm B.
Perry on the occasion of his retirement
which resulted into a mismatched pair during b-
D-galactosylation but allowed
a-L-fucosylation.
Ó 2012 Elsevier Ltd. All rights reserved.
Keywords:
Fucosylation
Galactosylation
N-Acylglucosamine
Regioselectivity
Reciprocal donor acceptor selectivity
Double diastereodifferentiation
The importance of donor–acceptor complementarity for suc-
cessful glycosylation reactions is well recognized.1 The terms
‘matched’ and ‘mismatched’ introduced by Paulsen in the early
80s were further elaborated by Fraser–Reid into the concept of re-
ciprocal donor acceptor selectivity (RDAS) to explain the regiose-
lective preferences shown by ‘disarmed’ or ‘armed’ glycosyl
donors when allowed to react with acceptors bearing two free hy-
droxyl groups of different reactivity.2 For instance using acceptors
displaying two free secondary hydroxyl groups, studies in Fraser–
Reid’s group showed that the armed donors seemed to favor reac-
tion at the most ‘accessible’ hydroxyl group although with less
overall regioselectivity, while the disarmed donors often favored
glycosylation at the hydroxyl group thought to be less accessible.3
In 1991, Spijker et al.,4 reported examples of glycosylation reac-
tions that led to donor/acceptor pairs that they also labeled
‘matched’ or ‘mismatched’ this time based on the notion of double
diastereodifferentiation introduced by Masamune et al.5 They ob-
served that despite the presence of a participating group at C-2, a
to the expected b glycosidic bond. To explain these results, the
authors proposed that, in the transition state leading to a b glyco-
sidic bond, the
tween the acceptor’s phathalimido and the benzoyl oxonium ion
in the donor, while the
donor did not induce such repulsions.4
In this paper we describe how -fucosylation and b- -galactosy-
D galactosyl donor induced steric repulsions be-
L
a-
L
D
lation of trisaccharide acceptor 1 (A0BA) (Scheme 1) displaying two
equatorial OH groups at C-3 of N-acylated glucosamine residues
led to different regioselectivities or different matched pairs.6 We
also report NMR evidence that the benzylidene group at the reduc-
ing end imposes conformational rigidity of residue A0 that may be a
factor in the observed regioselectivities. Benzylidene acetals in
glycosyl donors are known to direct the outcome of glycosylation
reactions through torsional or electronic effects,1,7 our results
may indicate that they play an equally important role in acceptors
by tuning reactivity of vicinal hydroxyl groups toward specific gly-
cosyl donors.
Selective chloroacetylation of diol 1 at low temperature gave
mono chloroacetate 2 quantitatively (Scheme 1) indicating that
the nonreducing end hydroxyl group was more ‘reactive’ toward
electrophiles than the reducing end hydroxyl group. Thus we ex-
pected that glycosylation reactions would also selectively take
place at the nonreducing end residue A0.
perbenzoylated
D-galactosyl donor led preferentially to an a glyco-
sidic bond when coupled at O-3 of an N-phthalimido glucosamine
acceptor while the L enantiomer galactosyl donor led preferentially
Fucosylation of diol 1 was attempted using the known8 armed
thioglycoside 3 (Scheme 2, Table 1) activated with NIS and TMSOTf
⇑
Corresponding author. Tel.: +1 519 824 4120x53809; fax: +1 519 766 1499.
E-mail address: fauzanne@uoguelph.ca (F.-I. Auzanneau).
0008-6215/$ - see front matter Ó 2012 Elsevier Ltd. All rights reserved.
http://dx.doi.org/10.1016/j.carres.2012.04.020

M. Guillemineau, F.-I. Auzanneau / Carbohydrate Research 357 (2012) 132–138
133
Table 1
Fucosylation of diol 1
AcO
O
OPiv
O
OBn
O
Ph
O
O
Methoda
Yields (%)
O
Entry
3 (equiv)
B
O
A'
A
O(CH2)6Cl
RO
HO
1
4
6
8
AcO
TCAHN
AcHN
1
2
3
4
5
6
1.2
3
4
1.2
3
4
A
A
A
B
B
B
65
20
—
30
—
17
57
63
40
31
7
—
—
—
11
—
—
—
—
17
3
58
78
1 R = H
ClAcCl
2 R =ClAc (quant.)
Scheme 1. Diol acceptor 1 and regioselective chloroacetylation.
—
a
Reagents and conditions: A, NIS/TMSOTf, 0 °C, CH2Cl2, 7–24 h; B, Cu(Br)2/
at low temperature.9 Our results showed that, under these condi-
tions, fucosylation occurred first at the nonreducing end glucosa-
mine residue A0 with mono fucosylated tetrasaccharide 4 being
the only product formed when 1–3 equiv of donor were used (en-
tries 1 and 2). Using 4 equiv of donor 3 (entry 3) led to the disap-
pearance of diol 1 giving predominantly tetrasaccharide 4 and
small amount of pentasaccharide 8. The structure of tetrasaccha-
ride 4 and position of the newly introduced fucosyl unit were con-
firmed by NMR (Table 2) after acetylation of the C-3A hydroxyl
group giving tetrasaccharide 5. The coupling constant measured
between H-1 and H-2 of the fucosyl units (3.7 Hz) in tetra- and
Bu4NBr, DMF–CH2Cl2, rt, 40 h.
Table 2
Selected 1H and 13C NMR chemical shifts for compounds 1, 2, 4–8, 10, 11
a
b
Compound
H-3a
H-3A0
C-4Ab
C-4A0
1
2
4
5
6
7
8
10
11
3.95
3.91
3.92
4.95
4.07
4.06
4.03
4.08
4.10
4.34
5.46
4.28
4.28
4.33
5.32
4.30
4.30
5.35
80.4
80.5
80.4
74.0
73.8
73.6
73.6
71.1
71.1
81.3
78.1
80.0
80.0
81.3
78.1
80.1
81.4
78.3
penta- saccharides 4 and 8 confirmed the formation of
a fucosidic
bonds in all instances. To prevent the fast degradation of donor 3,
we also investigated the fucosylation under copper(II) bromide-
tetrabutylammonium bromide activation (Table 2, entries 4–6).10
Under these milder conditions, lower selectivity of the fucosylation
was observed. Using 1.2 equiv of donor 3, mono fucosylated
a
dH in ppm.
dC in ppm.
b
tetrasaccharides 4 and 6, pentasaccharide 8 and unreacted diol 1
(entry 4) were isolated. Adding up to 4 equiv of donor led to the
disappearance of the diol acceptor and promptly converted the tet-
rasaccharides to pentasaccharide 8 (entry 6). The position of the
fucosyl unit in tetrasaccharide 6 was again confirmed by NMR (Ta-
ble 2) upon acetylation of the C-3A0 free hydroxyl group giving tet-
SEt
O
+
OBn
1
OBn
BnO
3
CuBr/Bu4NBr
AcO
or NIS/TMSOTf
rasaccharide 7. The
a configuration of the fucosidic bond in
tetrasaccharide 6 was confirmed by measuring the coupling con-
stant between H-1 and H-2 of the fucosyl unit (3.8 Hz). Thus, it is
clear from these reactions that a-L-fucosylation with the armed do-
nor 3 occurred preferentially at O-3 of the nonreducing end gluco-
samine residue A0 rather than at O-3 of the reducing end
glucosamine residue A.
OPiv
O
O
Ph
OBn
O
O
O
A'
HNTCA
OBn
B
O
RO
O
O
A
O(CH2)6Cl
AcO
O
AcHN
C'
We then investigated the b-D-galactosylation of trisaccharide 1
OBn
BnO
4 R = H
with the known11 peracetylated galactosyl bromide (9). Diol 1 was
first left to react with 1.5 equiv of disarmed bromide 9 under Helf-
rich activation at 50 °C. After 15 h of reaction, TLC showed that a
new product had formed but that a large amount of acceptor re-
mained unreacted. Over the next 24 h, more donor (up to
5.5 equiv) and activator (up to 6 equiv) were added and the reac-
tion was quenched when a 1 to 1 ratio of starting acceptor and
new product was observed by TLC. After purification, unreacted
diol 1 and b galactosylated tetrasaccharide 10 were isolated both
in 31% yield. The b configuration of the galactosidic bond was eas-
ily determined from the coupling constant measured between H-1
and H-2 of the galactose unit (ꢀ8.0 Hz) and the position of this res-
idue in tetrasaccharide 10 was established by NMR after acetyla-
tion of the remaining free hydroxyl group giving tetrasaccharide
11 (Table 2). This reaction was repeated starting with 5 equiv of
donor 9 (Scheme 3) and leaving the reaction to proceed for 5 h at
50 °C. Under these conditions, the tetrasaccharide 10 was isolated
in 67% yield and no other product was seen by TLC, nor isolated by
Ac2O
5
R = Ac
+
OPiv
O
AcO
OBn
O
O
Ph
O
O
A'
H NTCA
B
O
O
O
RO
A
O(CH2)6Cl
AcO
AcHN
O
C
OBn
OBn
BnO
6 R = H
Ac2O
O
7
R = Ac
+
OPiv
O
AcO
OBn
O
Ph
O
B
O
A'
O
O
O
A
O
O(CH2)6Cl
AcO
HNTCA
O
AcHN
OBn
chromatography. Thus it is clear that this b-D-galactosylation was
selective for the reducing end glucosamine residue A.
This work led to a couple of interesting NMR observations.
While glycosylation at the reducing end glucosamine A led to the
expected12 distortion of the 4C1 chair (JH-1A,H-2A = 5.4 Hz for 8;
4.6 Hz for 10; compared to 8.0 Hz for acceptor 1), the nonreducing
C'
OBn
O
OBn
C
BnO
OBn
BnO
8
Scheme 2. Fucosylation of diol acceptor 1.

134
M. Guillemineau, F.-I. Auzanneau / Carbohydrate Research 357 (2012) 132–138
On-going studies in our laboratory aim at shedding light on the im-
OAc
O
AcO
AcO
pact of 4,6-O-benzylidene and trichloroacetamido on glycosyla-
tions at the nonreducing end of trisaccharide 1 as well as further
understanding the factors governing these regioselectivities.
1
+
AcO
Br
9 (5 equiv)
1. Experimental section
1.1. General methods
Hg(CN)2
PhCH3/CH3NO2
50 ºC, 5 h
OPiv
O
1H NMR (600.13 MHz) and 13C NMR (150.9 MHz) spectra were
recorded with Bruker Avance spectrometers in CDCl3 (internal
standard, for 1H residual CHCl3 dH 7.24; for 13C: CDCl3 dC 77.0).
1H NMR and 13C NMR chemical shifts are reported in part per mil-
lion (ppm). Coupling constants (J) were obtained from a first-order
analysis of one-dimensional spectra and are reported in Hertz (Hz).
Assignments of proton and carbon resonances were based on two
dimensional 1H–1H and 13C–1H correlation experiments. 1H NMR
data are reported using standard abbreviations: singlet (s), doublet
(d), triplet (t), doublet of doublet (dd), broad singlet (br s), broad
triplet (br t), and multiplet (m). Analytical thin-layer chromatogra-
phy (TLC) was performed on aluminium plates precoated with Sil-
AcO
O
Ph
OBn
O
O
O
B
A'
O
O
RO
TCAHN
A
AcO
AcO
O(CH2)6Cl
O
O
AcHN
AcO
C
OAc
AcO
10
R = H (67%)
11 R = Ac (quant)
Ac2O
Scheme 3. Galactosylation of diol acceptor 1.
ica Gel 60 F254 (250 lm) containing a fluorescent indicator. The
end glucosamine unit A0 retained a well-defined 4C1 chair confor-
plates were visualized under UV and/or charred with a 20% solu-
tion of H2SO4 in EtOH. Compounds were purified by flash chroma-
tography with Silica Gel 60 (230–400 mesh) unless otherwise
stated. Solvents were distilled and dried according to standard pro-
cedures and organic solutions were dried over Na2SO4 and concen-
trated under reduced pressure. Molecular sieves were activated by
heating at 300 °C overnight under reduced pressure. All reagents
were purchased from commercial suppliers and used without fur-
ther purification. Reverse-phase HPLC purifications were carried
mation (J H-1A ,H2A = 8.0 Hz) upon fucosylation. As expected,9 the
C-4A chemical shift underwent, a large upfield shift (
d ꢀ 6–
7 ppm) upon fucosylation or acetylation at the vicinal O-3A which
was even more pronounced (
d ꢀ 9 ppm) in the galactosylated
0
0
D
D
analogues (Table 2, compare analogues 5, 8, 10, 11 and 1, 2, 4).
In sharp contrast, the impact of substitution at O-3A0 on the chem-
ical shift measured for C-4A0 only led to a 3 ppm upfield shift upon
acylation in analogues 2, 7, 11, and a ꢀ1 ppm upfield shift in the
fucosylated analogues 4, 5 and 8. Thus, it appears that the benzyl-
idene ring at the nonreducing end glucosamine ring A0 is prevent-
ing distortion to take place at this residue and limiting the impact
of the substitution at O-3 on the vicinal C-4 chemical shift.
out on Prep Nova PakÒ HR C18, 6
lm 60 Å columns using mixtures
of HPLC grade acetonitrile and milli-Q water. Optical rotations
were measured at 22 °C on a Rudolph Research Autopol III polarim-
eter and reported as follows: [a]D (c in g per 100 mL, solvent). High
In conclusion, our results support once again1–4 that the out-
come of selective glycosylation cannot be solely explained based
on the relative reactivities of hydroxyl groups. Our results suggest
that the nonreducing end 3-OH (A0) group in diol 1 is more reactive
toward small electrophiles than the reducing end 3-OH at residue
A. However, while the armed donor 3 showed a relative but non-
exclusive preference for this same hydroxyl group at residue A0,
the disarmed galactosyl donor 9 showed an exclusive preference
for the hydroxyl group at residue A. Therefore, these results may
be rationalized by the concept of reciprocal donor acceptor selec-
tivity (RDAS) formulated by Fraser–Reid.2,3 However, since the for-
resolution electrospray ionization mass spectra (HRESI MS) were
recorded by the analytical services of the McMaster Regional Cen-
tre for Mass Spectrometry, Hamilton, Ontario.
1.2. Analytical data for trisaccharide 1
[a]
+3.0 (c 1.0, CH2Cl2), 1H NMR (CDCl3, 600 MHz, 296 K): dH
D
7.47–7.43 (m, 2H, Ar), 7.38–7.28 (m, 8H, Ar), 6.95 (d, J = 6.9 Hz,
1H, NHA0), 5.57 (d, 1H, J = 7.9 Hz, NHA), 5.52 (s, 1H, ˜CHPh), 5.31
(d, 1H, J = 3.3 Hz, H-4B), 5.13 (d, 1H, J = 8.0 Hz, H-1A0), 5.09 (dd,
1H, J = 8.2, 9.9 Hz, H-2B), 4.71 (d, 1H, J = 8.0 Hz, H-1A), 4.68 (d,
1H, J = 12.4 Hz, CHHPh), 4.47 (d, 1H, J = 12.2 Hz, CHHPh), 4.38–
4.32 (m, 3H, H-1B, H-3A0, H-6A0a), 4.15 (dd, 1H, J = 4.7, 11.5 Hz,
H-6Ba), 3.97–3.92 (m, 2H, H-3A, H-6Bb), 3.90 (br s, 1H, OH-3A),
3.84–3.72 (m, 4H, H-3B, H-5B, H-6A0b, OCHHCH2), 3.67 (dd, 1H,
J = 3.7, 11.2 Hz, H-6Aa), 3.62 (dd, 1H, J = 3.7, 10.9 Hz, H-6Ab), 3.56
(t, 1H, J = 8.8 Hz, H-4A), 3.52–3.41 (m, 5H, H-5A, H-4A0, H-5A0,
OCHHCH2, CH2Cl), 3.38 (m, 1H, H-2A), 3.24 (m, 1H, H-2A0), 2.73
(br s, 1H, OH-3A0), 2.11, 2.02 (2s, 6H, 2OCOCH3), 1.96 (s, 3H,
NHCOCH3), 1.73 (m, 2H, O(CH2)4CH2CH2Cl), 1.56 (m, 2H,
OCH2CH2(CH2)3CH2Cl), 1.41 (m, 2H, O(CH2)3CH2(CH2)2Cl), 1.33
(m, 2H, O(CH2)2CH2(CH2)3Cl), 1.18 (s, 9H, C(CH3)3). 13C NMR
(125 MHz, CDCl3, 296 K): dC 178.1, 170.3, 169.8, 169.3, 162.2
(C@O), 138.2, 136.7 (quat Ar), 129.4, 128.5, 128.4, 127.8, 126.2
(Ar), 101.9 (˜CHPh), 101.1 (C-1B), 100.1 (C-1A), 99.2 (C-1A0), 92.3
(CCl3), 81.3 (C-4A0), 80.4 (C-4A), 75.8 (C-3B), 74.1 (C-5A), 73.6
(CH2Ph), 71.7 (C-5B), 71.2 (C-3A), 70.5 (C-2B), 69.4 (OCH2CH2),
69.1 (C-4B), 68.5 (C-3A0), 68.4 (C-6A0), 68.1 (C-6A), 66.1 (C-5A0),
62.0 (C-6B), 60.0 (C-2A0), 56.8 (C-2A), 45.0 (CH2Cl), 38.8
(C(CH3)3), 32.5 (O(CH2)4CH2CH2Cl), 29.3 (OCH2CH2(CH2)3CH2Cl),
mation of a b linkage with D-galactose was mismatched at the
nonreducing end glucosamine unit but matched at the reducing
end one, these observations also suggest that steric repulsions be-
tween the acyloxonium galactosyl donor and the trichloroacetam-
ido at C-2 of the nonreducing end unit A0 precluded the formation
of an
a-D galactosidic bond at O-3 of this residue. Thus, these re-
sults could also be rationalized under the double diastereodifferen-
tiation concept.4,5 It is clear from the NMR observations reported
above, that the 4,6-O-benzylidene group at the nonreducing end
impacted rigidity of this glucosamine unit. Thus, we also suggest
that the lack of flexibility of the nonreducing end glucosamine unit
(A0) imposed by the 4,6-O-benzylidene group disfavored the forma-
tion of a b-D-galactosidic linkage at O-3 of this residue. In contrast,
glycosylation at the reducing end glucosamine unit (A) was al-
lowed and led to distortion of the 4C1 conformation at this residue.
This latter hypothesis supports that, similarly to their ability to
direct the outcome of glycosylations when present in glycosyl
donors,1,7 benzylidene protecting groups in glycosyl acceptors play
an important role in promoting or impeding glycosylations.

M. Guillemineau, F.-I. Auzanneau / Carbohydrate Research 357 (2012) 132–138
135
27.0 (C(CH3)3), 26.5 (O(CH2)3CH2(CH2)2Cl), 25.2 (O(CH2)2
CH2(CH2)3Cl), 23.6 (NHCOCH3), 21.2, 20.8 (OCOCH3). HRESIMS
calcd for C51H68Cl4N2O19Na[M+Na]+ 1175.3098, found: 1175.3018.
0 °C and 12.5
(0.63
was stirred at 0 °C for 7.5 h. The reaction was quenched with
NEt3 (1.2 L, 0.00867 mmol, 0.5 equiv), diluted with CH2Cl2
l
L of a 50
l
L/mL solution of TMSOTf in dry CH2Cl2
l
L, 0.00346 mmol, 0.2 equiv) was added and the mixture
l
1.3. 6-Chlorohexyl 2-acetamido-4-O-[2,4-di-O-acetyl-6-O-piva-
loyl-3-O-(4,6-O-benzylidene-3-O-chloroacetyl-2-deoxy-2-tri-
(10 mL) and washed with 20% Na2S2O3 (1 ꢁ 15 mL). The aq layer
was re-extracted with CH2Cl2 (3 ꢁ 10 mL) and the combined or-
ganic layers were dried and concentrated. When using 1.2–3 equiv
of donor 3 the unreacted acceptor 1 and tetrasaccharide 4 were
purified as followed: flash chromatography of the residue
(EtOAc–hexanes, 4:6 then 1:1 then 100% EtOAc) gave glycosyl
acceptor 1 (13.0–4.0 mg, 65–20% see Table 1) and tetrasaccharide
4 contaminated with succinimide. Tetrasaccharide 4 was obtained
pure (4.7–15.5 mg, 17–57% see Table 1) by RP HPLC (CH3CN/
H2O = 80:100–100:0, 30 min). When using 4 equiv of donor 3, tet-
rasaccharide 4 and pentasaccharide 8 were purified as follows:
flash chromatography of the residue (EtOAc–hexanes, 4:6 then
1:1 then 100% EtOAc) gave a mixture of the two products contam-
inated with succinimide. These two compounds were separated by
RP HPLC (CH3CN/H2O = 80:100–100:0, 30 min) to give pure tetra-
saccharide 4 (17.1 mg, 63%) and pure pentasaccharide 8 (5.8 mg,
17%).
chloroacetamido-b-D-glucopyranosyl)-b-D-galactopyranosyl]-
6-O-benzyl-2-deoxy-b-D-glucopyranoside (2)
Chloroacetyl chloride (23.3 lL, 0.293 mmol, 1 equiv) was added
at 0 °C to a stirred solution of the trisaccharide 1 (338.2 mg,
0.293 mmol) in dry CH2Cl2 (60 mL) containing dry pyridine
(47.4 lL, 0.586 mmol, 2 equiv). The reaction was left at 0 °C under
N2 for 2 h then was sequentially washed with HCl 2 N (1 ꢁ 50 mL)
and saturated aq NaHCO3 (1 ꢁ 50 mL). The aq layers were re-ex-
tracted with CH2Cl2 (2 ꢁ 20 mL) and the combined organic layers
were dried and concentrated to give the selectively chloroacetylat-
ed trisaccharide 2 (360.6 mg, quant) as a slightly yellowish foam.
[
a]
D
ꢂ6.1 (c 0.9, CH2Cl2), 1H NMR (CDCl3, 600 MHz, 295 K): dH
7.42–7.38 (m, 2H, Ar), 7.32–7.27 (m, 8H, Ar), 6.90 (d, 1H,
J = 8.8 Hz, NHA0), 5.57 (d, 1H, J = 7.9 Hz, NHA), 5.50 (s, 1H, ˜CHPh),
5.46 (t, 1H, J = 10.0 Hz, H-3A0), 5.27 (d, 1H, J = 2.0 Hz, H-4B), 5.08
(dd, 1H, J = 8.3, 9.9 Hz, H-2B), 4.79 (d, 1H, J = 8.0 Hz, H-1A0), 4.70–
4.65 (m, 2H, H-1A, CHHPh), 4.48 (d, 1H, J = 12.1 Hz, CHHPh), 4.38
(d, 1H, J = 8.1 Hz, H-1B), 4.34 (dd, 1H, J = 4.9, 10.6 Hz, H6Aa0),
4.14 (dd, 1H, J = 4.6, 11.6 Hz, H-6Ba), 4.04 (d, 1H, J = 15.1 Hz,
COCHHCl), 4.00 (d, 1H, J = 15.1 Hz, COCHHCl), 3.98–3.89 (m, 3H,
H-3A, H-6Bb, OH-3A), 3.84–3.71 (m, 6H, H-3B, H-5B, H-2A0, H-
4A0, H-6A0b, OCHHCH2), 3.67 (dd, 1H, J = 2.1, 11.2 Hz, H-6Aa),
3.63 (dd, 1H, J = 3.6, 11.0 Hz, H-6Ab), 3.57 (t, 1H, J = 8.8 Hz, H-
4A), 3.56–3.40 (m, 6H, H-2A, H-5A, H-5A0, OCHHCH2, CH2Cl),
2.12, 2.01 (2s, 6H, 2OCOCH3), 1.97 (s, 3H, NHCOCH3), 1.73 (m,
2H, O(CH2)4CH2CH2Cl), 1.55 (m, 2H, OCH2CH2(CH2)3CH2Cl), 1.41
(m, 2H, O(CH2)3CH2(CH2)2Cl), 1.33 (m, 2H, O(CH2)2CH2(CH2)3Cl),
1.18 (s, 9H, C(CH3)3). 13C NMR (125 MHz, CDCl3, 295 K): dC 178.1,
170.3, 170.1, 169.1, 167.3, 162.1 (C@O), 138.2, 136.4 (quat Ar),
129.3, 128.4, 128.3, 127.7, 126.1 (Ar), 101.5 (˜CHPh), 101.0 (C-
1B), 100.2 (C-1A), 100.1 (C-1A0), 92.0 (CCl3), 80.5 (C-4A), 78.1 (C-
4A0), 75.3 (C-3B), 74.1 (C-5A), 73.6 (CH2Ph), 71.9 (C-3A0), 71.6 (C-
5B), 71.4 (C-3A), 70.6 (C-2B), 69.4 (OCH2CH2), 68.7 (C-4B), 68.2
(C-6A0), 68.1 (C-6A), 66.4 (C-5A0), 62.1 (C-6B), 56.8 (C-2A0), 56.6
(C-2A), 45.0 (CH2Cl), 40.4 (COCH2Cl), 38.8 (C(CH3)3), 32.5
(O(CH2)4CH2CH2Cl), 29.3 (OCH2CH2(CH2)3CH2Cl), 27.0 (C(CH3)3),
26.5 (O(CH2)3CH2(CH2)2Cl), 25.2 (O(CH2)2CH2(CH2)3Cl), 23.6
(NHCOCH3), 21.2, 20.7 (OCOCH3). HRESIMS calcd for
1.4.2. Method B
A mixture of glycosyl acceptor 1 (20 mg, 0.0173 mmol for 1.2
and 3 equiv of 3 and 27 mg, 0.0234 mmol for 4 equiv of 3), thiogly-
coside 3 (9.9–44.7 mg, 1.2–4 equiv) and activated powdered 4 Å
molecular sieves (200 mg) in a 1:1 mixture of dry DMF and CH2Cl2
(2 mL or 2.6 mL when using 4 equiv of donor 3) was stirred for 3 h
at rt under N2. CuBr2 (5.8–26.1 mg, 1.5–5 equiv) and Bu4NBr (8.9–
38.4 mg, 1.6–5 equiv) were then added and the reaction was left at
rt for 40 h. The reaction mixture was filtered over CeliteÒ and the
solids were washed with CH2Cl2 (15 mL). The filtrate was washed
sequentially with brine (1 ꢁ 15 mL) and saturated aq NaHCO3
(6 ꢁ 15 mL) and the aq layers were re-extracted with CH2Cl2
(2 ꢁ 15 mL). The combined organic layers were dried and concen-
trated. When using 1.2 equiv of 3, flash chromatography of the res-
idue (EtOAc–hexanes, 4:6 then 1:1) gave recovered glycosyl
acceptor 1 (6.0 mg, 30%) and a mixture of products 4, 6, and 8 that
were separated by RP HPLC (CH3CN/H2O = 80:100–100:0, 30 min):
4 (10.8 mg, 40%), 6 (3.0 mg, 11%), 8 (1.2 mg, 3%). isolated as color-
less amorphous glass. When using 3 or 4 equiv of donor 3, flash
chromatography of the residue obtained after work up (EtOAc–
hexanes, 3:7 then 4:6 then 100% EtOAc) gave pure tetrasaccharide
4 (8.9 and 2.6 mg, 31% and 7%, respectively) and pentasaccharide 8
(20.6 and 36.3 mg, 58% and 78%, respectively).
C
53H70Cl5N2O20 [M+H]+ 1229.2965, found: 1229.2921.
1.4.3. Analytical data for 4
1.4. 6-Chlorohexyl 2-acetamido-4-O-[2,4-di-O-acetyl-6-O-piva-
loyl-3-O-(4,6-O-benzylidene-3-O-(2,3,4-tri-O-benzyl- -fuco
pyranosyl)-2-deoxy-2-trichloroacetamido-b- -glucopyranosyl)-
b- -galactopyranosyl]-6-O-benzyl-2-deoxy-b- -glucopyranoside
(4), 6-Chlorohexyl 2-acetamido-4-O-[2,4-di-O-acetyl-6-O-piva-
loyl-3-O-(4,6-O-benzylidene-2-deoxy-2-trichloroacetamido-b-
Colorless glass, [
a
]
ꢂ21.2 (c 0.4, CH2Cl2), 1H NMR (CDCl3,
D
a-L
600 MHz, 295 K): dH 7.44–7.40 (m, 2H, Ar), 7.36–7.20 (m, 23H,
Ar), 6.90 (br s, 1H, NHA0), 5.56 (d, 1H, J = 7.7 Hz, NHA), 5.47 (s,
1H, ˜CHPh), 5.30 (d, 1H, J = 3.5 Hz, H-4B), 5.14 (d, 1H, J = 8.0 Hz,
H-1A0), 3.72 (d, 1H, J = 3.7 Hz, H-1C0), 5.07 (dd, 1H, J = 8.2,
10.0 Hz, H-2B), 4.92 (d, 1H, J = 11.8 Hz, CHHPh), 4.85 (d, 1H,
J = 11.5 Hz, CHHPh), 4.70 (d, 1H, J = 7.9 Hz, H-1A), 4.69–4.64 (m,
3H, CH2Ph, CHHPh), 4.61 (d, 1H, J = 11.8 Hz, CHHPh), 4.54 (d, 1H,
J = 11.6 Hz, CHHPh), 4.46 (d, 1H, J = 12.1 Hz, CHHPh), 4.37–4.31
(m, 2H, H-1B, H-6A0a), 4.28 (t, 1H, J = 9.3 Hz, H-3A0), 4.15 (dd, 1H,
J = 4.6, 11.6 Hz, H-6Ba), 4.03–3.97 (m, 2H, H-2C0, H-5C0), 3.96–
3.88 (m, 3H, H-3A, H-6Bb, H-3C0), 3.84–3.78 (m, 2H, H-3B,
OCHHCH2), 3.75 (dd, 1H, J = 4.7, 7.7 Hz, H-5B), 3.70 (t, 1H,
J = 10.2 Hz, H-6A0b), 3.67–3.58 (m, 3H, H-6Aab, H-4A0), 3.56–3.35
(m, 9H, H-2A, H-4A, H-5A, H-2A0, H-5A0, H-4C0, CH2Cl, OCHHCH2),
2.10, 1.94 (2s, 6H, 2OCOCH3), 1.96 (s, 3H, NHCOCH3), 1.73 (m,
2H, O(CH2)4CH2CH2Cl), 1.54 (m, 2H, OCH2CH2(CH2)3CH2Cl), 1.41
(m, 2H, O(CH2)3CH2(CH2)2Cl), 1.33 (m, 2H, O(CH2)2CH2(CH2)3Cl),
1.18 (s, 9H, C(CH3)3), 0.7 (d, 3H, J = 6.4 Hz, H-6C0). 13C NMR
D
D
D
D
-glucopyranosyl)-b-
4-tri-O-benzyl- -fucopyranosyl)-2-deoxy-b-
side (6), 6-Chlorohexyl 2-acetamido-4-O-[2,4-di-O-acetyl-6-O-
pivaloyl-3-O-(4,6-O-benzylidene-3-O-(2,3,4-tri-O-benzyl-
fucopyranosyl)-2-deoxy-2-trichloroacetamido-b- -glucopyr-
anosyl)-b- -galactopyranosyl]-6-O-benzyl-3-O-(2,3,4-tri-O-
benzyl- -fucopyranosyl)-2-deoxy-b- -glucopyranoside (8)
D
-galactopyranosyl]-6-O-benzyl-3-O-(2,3,
a-
L
D
-glucopyrano-
a-L-
D
D
a
-
L
D
1.4.1. Method A
A mixture of acceptor 1 (20 mg, 0.0173 mmol), thioglycoside 3
(9.9–33.1 mg, 0.0278–0.0693 mmol, 1.2–4 equiv) and NIS (8.2–
20.5 mg, 2–5 equiv) in dry CH2Cl2 (2 mL) under N2 was cooled to

136
M. Guillemineau, F.-I. Auzanneau / Carbohydrate Research 357 (2012) 132–138
(125 MHz, CDCl3, 295 K): dC 178.1, 170.3, 169.9, 169.1, 161.6
(C@O), 138.9, 138.4, 138.2, 137.0 (quat Ar), 129.3, 128.4, 128.3,
128.2, 127.7, 127.6, 127.5, 127.4, 127.2, 126.3 (Ar), 101.9 (˜CHPh),
101.1 (C-1B), 100.1 (C-1A), 98.9 (C-1A0), 98.3 (C-1C0), 91.9 (CCl3),
80.4 (C-4A), 80.0 (C-4A0), 79.9 (C-3C0), 77.3 (C-4C0), 76.1 (C-2C0),
75.1 (C-3B), 74.9 (CH2Ph), 74.1 (C-5A), 73.8 (CH2Ph), 73.7 (C-3A0),
73.6 (CH2Ph), 72.5 (CH2Ph), 71.7 (C-5B), 71.2 (C-3A), 70.5 (C-2B),
69.4 (OCH2CH2), 68.9 (C-4B), 68.5 (C-6A0), 68.2 (C-6A), 66.8 (C-
5C0), 66.1 (C-5A0), 62.1 (C-6B), 60.3 (C-2A0), 56.7 (C-2A), 45.0
(CH2Cl), 38.8 (C(CH3)3), 32.5 (O(CH2)4CH2CH2Cl), 29.2 (OCH2CH2
(CH2)3CH2Cl), 27.0 (C(CH3)3), 26.5 (O(CH2)3CH2(CH2)2Cl), 25.2
(O(CH2)2CH2(CH2)3Cl), 23.6 (NHCOCH3), 21.2, 20.8 (OCOCH3), 16.1
(C-6C0). HRESIMS calcd for C78H97Cl4N2O23 [M+H]+ 1569.5236,
found: 1569.5256.
1.66 (m, 2H, O(CH2)4CH2CH2Cl), 1.44 (m, 2H, OCH2CH2(CH2)3
CH2Cl), 1.33 (m, 2H, O(CH2)3CH2(CH2)2Cl), 1.23 (m, 2H, O(CH2)2
CH2(CH2)3Cl), 1.18 (s, 9H, C(CH3)3), 1.12 (d, 3H, J = 6.5 Hz, H-6C),
0.72 (d, 3H, J = 6.4 Hz, H-6C0). 13C NMR (125 MHz, CDCl3, 295 K):
dC 177.7, 170.1, 169.6, 169.3, 161.6 (C@O), 139.0, 138.9, 138.8,
138.6, 138.5, 138.4, 138.0, 137.0 (quat Ar), 129.3, 128.5, 128.4,
128.3, 128.2, 127.8, 127.7, 127.6, 127.5, 127.3, 127.2, 127.1, 126.2
(Ar), 101.9 (˜CHPh), 99.6 (C-1A), 99.5 (C-1B), 99.0 (C-1A0), 98.2
(C-1C0), 96.8 (C-1C), 91.9 (CCl3), 80.1 (C-4A0), 79.8 (C-3C0), 79.7
(C-3C), 77.3 (C-4C0), 77.2 (C-4C), 76.5 (C-2C), 76.2 (C-2C0), 75.3
(C-3B), 74.9 (CH2Ph), 74.4 (CH2Ph), 74.1 (C-5A), 73.8 (CH2Ph),
73.6 (C-4A, C-3A0), 73.4 (CH2Ph), 73.2 (CH2Ph), 72.9 (C-3A), 72.6
(CH2Ph), 72.5 (CH2Ph), 70.9 (C-5B), 70.6 (C-2B), 69.2 (OCH2CH2),
68.8 (C-6A, C-4B), 68.5 (C-6A0), 66.8 (C-5C0), 66.5 (C-5C), 66.1 (C-
5A0), 61.2 (C-6B), 60.2 (C-2A0), 54.8 (C-2A), 45.0 (CH2Cl), 38.7
(C(CH3)3), 32.5 (O(CH2)4CH2CH2Cl), 29.2 (OCH2CH2 (CH2)3CH2Cl),
27.1 (C(CH3)3), 26.6 (O(CH2)3CH2(CH2)2Cl), 25.2 (O(CH2)2CH2
(CH2)3Cl), 23.1 (NHCOCH3), 21.2, 20.8 (OCOCH3), 16.6 (C-6C), 16.1
(C-6C0). HRESIMS calcd for C105H125Cl4N2O27 [M+H]+ 1985.7224,
found: 1985.7214.
1.4.4. Analytical data for 6
Colorless glass, [
a
]
D
ꢂ41.4 (c 1.0, CH2Cl2), 1H NMR (CDCl3,
600 MHz, 295 K): dH 7.47–7.44 (m, 2H, Ar), 7.38–7.23 (m, 23H,
Ar), 6.91 (br s, 1H, NHA0), 5.90 (d, 1H, J = 7.4 Hz, NHA), 5.53 (s,
1H, ˜CHPh), 5.27 (d, 1H, J = 3.5 Hz, H-4B), 5.10 (d, 1H, J = 8.0 Hz,
H-1A0), 5.06 (d, 1H, J = 3.8 Hz, H-1C), 4.97 (dd, 1H, J = 8.4, 10.0 Hz,
H-2B), 4.93 (d, 1H, J = 11.8 Hz, CHHPh), 4.86–4.78 (m, 3H, H-1A,
2CHHPh), 4.74–4.60 (m, 4H, 4CHHPH), 4.41–4.32 (m, 4H, H-1B,
H-3A0, H-6A0a, CHHPh), 4.27 (m, 1H, H-5C), 4.10–4.06 (m, 2H, H-
3A, H-2C), 4.02 (dd, 1H, J = 6.8, 11.1 Hz, H-6Ba), 3.91 (dd, 1H,
J = 6.9, 11.2 Hz, H-6Bb), 3.87 (dd, 1H, J = 2.6, 6.1 Hz, H-3C), 3.85–
3.79 (m, 2H, H-4A, H-6A0b), 3.77–3.72 (m, 2H, H-6Aab), 3.70 (m,
1H, OCHHCH2), 3.64 (dd, 1H, J = 3.5, 10.0 Hz, H-3B), 3.59 (s, 1H,
H-4C), 3.54 (t, 1H, J = 6.8 Hz, H-5B), 3.52–3.41 (m, 6H, H-2A, H-
5A, H-4A0, H-5A0, CH2Cl), 3.35 (m, 1H, OCHHCH2), 3.23 (m, 1H, H-
2A0), 2.70 (br s, 1H, OH-3A0), 2.02, 1.93 (2s, 6H, 2OCOCH3), 1.73
(s, 3H, NHCOCH3), 1.67 (m, 2H, O(CH2)4CH2CH2Cl), 1.45 (m, 2H,
OCH2CH2(CH2)3CH2Cl), 1.33 (m, 2H, O(CH2)3CH2(CH2)2Cl), 1.24
(m, 2H, O(CH2)2CH2(CH2)3Cl), 1.18 (s, 9H, C(CH3)3), 1.12 (d, 3H,
J = 6.5 Hz, H-6C). 13C NMR (125 MHz, CDCl3, 295 K): dC 177.7,
170.1, 169.5, 169.4, 162.2 (C@O), 139.0, 138.9, 138.6, 138.1,
136.7 (quat Ar), 129.4, 128.5, 128.4, 128.3, 128.2, 127.9, 127.6,
127.5, 127.4, 127.1, 126.2 (Ar), 101.9 (˜CHPh), 99.5 (C-1A), 99.4
(C-1B), 99.3 (C-1A0), 97.0 (C-1C), 92.2 (CCl3), 81.3 (C-4A0), 79.9 (C-
3C), 77.2 (C-4C), 76.6 (C-2C), 76.0 (C-3B), 74.4 (CH2Ph), 74.2 (C-
5A), 73.8 (C-4A), 73.5 (CH2Ph) 73.4 (CH2Ph), 73.1 (C-3A), 72.6
(CH2Ph), 70.9 (C-5B), 70.6 (C-2B), 69.3 (OCH2CH2), 69.0 (C-4B),
68.7 (C-6A0), 68.6 (C-3A0), 68.4 (C-6A), 66.5 (C-5C), 66.0 (C-5A0),
61.0 (C-6B), 59.9 (C-2A0), 55.1 (C-2A), 45.0 (CH2Cl), 38.7
(C(CH3)3), 32.5 (O(CH2)4CH2CH2Cl), 29.2 (OCH2CH2(CH2)3CH2Cl),
27.1 (C(CH3)3), 26.6 (O(CH2)3CH2(CH2)2Cl), 25.2 (O(CH2)2
CH2(CH2)3Cl), 23.2 (NHCOCH3), 21.2, 20.8 (OCOCH3), 16.7 (C-6C).
HRESIMS calcd for C78H97Cl4N2O23 [M+H]+ 1569.5236, found:
1569.5219.
1.5. 6-Chlorohexyl 2-acetamido-4-O-[2,4-di-O-acetyl-6-O-piva-
loyl-3-O-(4,6-O-benzylidene-3-O-(2,3,4-tri-O-benzyl-
a-L-fucopyr-
anosyl)-2-deoxy-2-trichloroacetamido-b- -glucopyranosyl)-b-D-
D
galactopyranosyl]-6-O-benzyl-3-O-acetyl-2-deoxy-b-D-gluco-
pyranoside (5)
Tetrasaccharide 4 (2.9 mg, 1.846 lmol) was treated with a 1:1
mixture of Ac2O/pyridine (2 mL) at 50 °C for 2 h. The mixture was
co-concentrated with PhMe (3 ꢁ 5 mL) and the residue was dis-
solved in CH2Cl2 (10 mL) and sequentially washed with HCl 2 N
(1 ꢁ 10 mL) and saturated aq NaHCO3 (1 ꢁ 10 mL). The organic
layer was dried and concentrated. Flash column chromatography
of the residue (EtOAc–hexanes, 6:4) gave 5 (2.9 mg, 97%) as a color-
less amorphous glass. [
a
]
D
ꢂ28.3 (c 0.3, CH2Cl2), 1H NMR (CDCl3,
600 MHz, 295 K): dH 7.43–7.40 (m, 2H, Ar), 7.36–7.20 (m, 23H,
Ar), 6.86 (d, 1H, J = 7.1 Hz, NHA0), 5.61 (d, 1H, J = 9.3 Hz, NHA),
5.48 (s, 1H, ˜CHPh), 5.26 (d, 1H, J = 3.5 Hz, H-4B), 5.13 (d, 1H,
J = 7.9 Hz, H-1A0), 5.08 (d, 1H, J = 3.7 Hz, H-1C0), 4.97–4.93 (m, 3H,
H-3A, H-2B, CHHPh), 4.85 (d, 1H, J = 11.5 Hz, CHHPh), 5.68 (s, 2H,
CH2Ph), 4.65 (d, 1H, J = 12.1 Hz, CHHPh), 4.61 (d, 1H, J = 11.8 Hz,
CHHPh), 4.54 (d, 1H, J = 11.5 Hz, CHHPh), 4.45 (d, 1H, J = 12.1 Hz,
CHHPh), 4.35 (d, 1H, J = 7.0 Hz, H-1A), 4.34–4.26 (m, 3H, H-1B, H-
3A0, H-6A0a), 4.04 (dd, 1H, J = 5.9, 11.3 Hz, H-6Ba), 4.02–3.93 (m,
4H, H-2A, H-6Bb, H-2C0, H-5C0), 3.91 (dd, 1H, J = 2.6, 10.1 Hz, H-
3C0), 3.83 (t, 1H, J = 7.9 Hz, H-4A), 3.79 (m, 1H, OCHHCH2), 3.75–
3.59 (m, 6H, H-6Aab, H-3B, H-5B, H-4A0, H-6A0b), 3.53 (d, 1H,
J = 2.4 Hz, H-4C0), 3.52–3.47 (m, 3H, H-5A0,CH2Cl), 3.47–3.35 (m,
3H, H-5A, H-2A0, OCHHCH2), 2.10, 1.98, 1.93 (3s, 9H, 3OCOCH3),
1.93 (s, 3H, NHCOCH3), 1.73 (m, 2H, O(CH2)4CH2CH2Cl), 1.54 (m,
2H, OCH2CH2(CH2)3CH2Cl), 1.40 (m, 2H, O(CH2)3CH2(CH2)2Cl), 1.31
(m, 2H, O(CH2)2CH2(CH2)3Cl), 1.19 (s, 9H, C(CH3)3), 0.7 (d, 3H,
J = 6.4 Hz, H-6C0). 13C NMR (125 MHz, CDCl3, 295 K): dC 178.0,
170.7, 169.9, 169.1, 161.6 (C@O), 138.9, 138.5, 138.4, 137.9, 137.0
(quat Ar), 129.3, 128.5, 128.4, 128.3, 128.2, 127.9, 127.8, 127.6,
127.5, 127.4, 127.2, 126.3 (Ar), 101.9 (˜CHPh), 101.2 (C-1A), 100.4
(C-1B), 98.8 (C-1A0), 98.2 (C-1C0), 92.0 (CCl3), 80.0 (C-4A0), 79.9 (C-
3C0), 77.4 (C-4C0), 76.1 (C-2C0), 75.4 (C-3B), 74.9 (CH2Ph), 74.7 (C-
5A), 74.0 (C-4A), 73.8 (CH2Ph), 73.6 (C-3A0), 73.5 (CH2Ph), 72.5
(CH2Ph), 72.0 (C-3A), 71.0 (C-5B), 70.8 (C-2B), 69.2 (OCH2CH2),
68.9 (C-4B), 68.6 (C-6A0), 67.9 (C-6A), 66.8 (C-5C0), 66.1 (C-5A0),
61.5 (C-6B), 60.4 (C-2A0), 52.7 (C-2A), 45.0 (CH2Cl), 38.7 (C(CH3)3),
32.5 (O(CH2)4CH2CH2Cl), 29.2 (OCH2CH2(CH2)3CH2Cl), 27.1
(C(CH3)3), 26.5 (O(CH2)3CH2(CH2)2Cl), 25.2 (O(CH2)2CH2(CH2)3Cl),
23.3 (NHCOCH3), 21.2, 20.8 (OCOCH3), 16.1 (C-6C0). HRESIMS calcd
for C80H99Cl4N2O24 [M+H]+ 1611.5342, found: 1611.5294.
1.4.5. Analytical data for 8
Colorless glass, [
a
]
D
ꢂ61.5 (c 1.0, CH2Cl2), 1H NMR (CDCl3,
600 MHz, 295 K): dH 7.44–7.40 (m, 2H, Ar), 7.37–7.22 (m, 38H,
Ar), 6.90 (d, 1H, J = 7.3 Hz, NHA0), 5.98 (d, 1H, J = 7.7 Hz, NHA),
5.48 (s, 1H, ˜CHPh), 5.26 (d, 1H, J = 3.4 Hz, H-4B), 5.12–5.09 (m,
2H, H-1A0, H-1C0), 5.08 (d, 1H, J = 3.7 Hz, H-1C), 4.99–4.77 (m, 6H,
H-2B, 5CHHPh), 4.76 (d, 1H, J = 5.4 Hz, H-1A), 4.73–4.60 (m, 6H,
CH2Ph, 4CHHPh), 4.59–4.52 (m, 2H, 2CHHPh), 4.39–4.32 (m, 3H,
H-1B, H-6A0a, CHHPh), 4.30 (t, 1H, J = 9.3 Hz, H-3A0), 4.21 (m, 1H,
H-5C), 4.08 (dd, 1H, J = 3.7, 10.1 Hz, H-2C), 4.07–3.98 (m, 4H,
H-3A, H-6Ba, H-2C0, H-5C0), 3.94–3.89 (m, 2H, H-6Bb, H-3C0), 3.86
(dd, 1H, J = 2.5, 10.1 Hz, H-3C), 3.84–3.79 (m, 2H, H-4A, H-6Aa),
3.74–3.65 (m, 4H, H-6Ab, H-3B, H-6A0b,OCHHCH2), 3.63 (t, 1H,
J = 9.2 Hz, H-4A0), 3.58 (d, 1H, J = 2.4 Hz, H-4C), 3.56–3.43 (m, 8H,
H-2A, H-5A, H-5B, H-2A0, H-5A0, H-4C0, CH2Cl), 3.34 (m, 1H,
OCHHCH2), 1.97, 1.96 (2s, 6H, 2OCOCH3), 1.77 (s, 3H, NHCOCH3),

M. Guillemineau, F.-I. Auzanneau / Carbohydrate Research 357 (2012) 132–138
137
1.6. 6-Chlorohexyl 2-acetamido-4-O-[2,4-di-O-acetyl-6-O-piva-
loyl-3-O-(4,6-O-benzylidene-3-O-acetyl-2-deoxy-2-trichlo-
1H, J = 8.0 Hz, H-1A0), 5.13 (dd, 1H, J = 8.1, 10.3 Hz, H-2C), 5.06 (dd,
1H, J = 3.2, 10.4 Hz, H-3C), 5.02 (t, 1H, J = 8.6 Hz, H-2B), 4.89 (d, 1H,
J = 7.9 Hz, H-1C), 4.56 (d, 1H, J = 11.5 Hz, CHHPh), 4.48 (d, 1H,
J = 11.5 Hz, CHHPh), 4.34–4.27 (m, 3H, H-1B, H-3A0, H-6A0a), 4.24
(d, 1H, J = 4.6 Hz, H-1A), 4.16 (dd, 1H, J = 8.5, 10.8 Hz, H-6Ba),
4.10–4.01 (m, 5H, H-2A, H-3A, H-6Bb, H-6Cab), 3.98–3.90 (m, 3H,
H-3B, H-5B, H-5C), 3.77–3.72 (m, 2H, H-5A, H-6A0b), 3.71–3.61
(m, 4H, H-4A, H-6Aab, OCHHCH2), 3.52–3.45 (m, 4H, H-4A0, H-
5A0,CH2Cl), 3.31–3.22 (m, 2H, H-2A0,OCHHCH2), 2.98 (br s, 1H,
OH-3A0), 2.12, 2.11, 2.07, 2.03, 2.01, 1.95 (6s, 18H, 6OCOCH3),
2.00 (s, 3H, NHCOCH3), 1.73 (m, 2H, O(CH2)4CH2CH2Cl), 1.51 (m,
2H, OCH2CH2(CH2)3CH2Cl), 1.41 (m, 2H, O(CH2)3CH2(CH2)2Cl),
1.29 (m, 2H, O(CH2)2CH2(CH2)3Cl), 1.18 (s, 9H, C(CH3)3). 13C NMR
(125 MHz, CDCl3, 295 K): dC 177.6, 170.8, 170.3, 170.2, 170.0,
169.7, 162.0 (C@O), 138.3, 136.7 (quat Ar), 129.4, 128.4, 127.8,
127.7, 126.2 (Ar), 101.8 (˜CHPh), 100.4 (C-1A), 99.2 (C-1A0), 98.6
(C-1B), 98.5 (C-1C), 92.3 (CCl3), 81.4 (C-4A0), 75.6 (C-5A, C-5C),
74.9 (C-3B), 73.4 (CH2Ph), 72.1 (C-3A), 71.1 (C-4A, C-2B), 70.8 (C-
5B), 70.7 (C-3C), 70.1 (C-6A), 69.1 (OCH2CH2), 68.7 (C-4B), 68.6
(C-3A0), 68.3 (C-2C, C-6A0), 67.0 (C-4C), 66.1 (C-5A0), 60.5 (C-6C,
C-6B), 59.8 (C-2A0), 49.4 (C-2A), 45.0 (CH2Cl), 38.7 (C(CH3)3), 32.4
(O(CH2)4CH2CH2Cl), 29.2 (OCH2CH2(CH2)3CH2Cl), 27.1 (C(CH3)3),
26.6 (O(CH2)3CH2(CH2)2Cl), 25.3 (O(CH2)2CH2(CH2)3Cl), 23.1
(NHCOCH3), 21.6, 20.9, 20.7, 20.6 (OCOCH3). HRESIMS calcd for
roacetamido-b-
benzyl-3-O-(2,3,4-tri-O-benzyl-
b- -glucopyranoside (7)
D
-glucopyranosyl)-b-
D-galactopyranosyl]-6-O-
a
-L
-fucopyranosyl)-2-deoxy-
D
Tetrasaccharide 6 (20 mg, 0.0127 mmol) was acetylated and
isolated as described for compound 5 to give 7 pure (20 mg, 97%)
as a colorless glass. [
a]
D
ꢂ48.5 (c 1.0, CH2Cl2), 1H NMR (CDCl3,
600 MHz, 295 K): dH 7.44–7.41 (m, 2H, Ar), 7.37–7.22 (m, 23H,
Ar), 7.01 (d, 1H, J = 8.9 Hz, NHA0), 5.94 (d, 1H, J = 7.9 Hz, NHA),
5.50 (s, 1H, ˜CHPh), 5.36 (t, 1H, J = 10.1 Hz, H-3A0), 5.22 (d, 1H,
J = 3.6 Hz, H-4B), 5.08 (d, 1H, J = 4.0 Hz, H-1C), 4.97–4.91 (m, 2H,
H-2B, CHHPh), 4.83–4.78 (m, 2H, 2CHHPh), 4.76 (d, 1H, J = 5.4 Hz,
H-1A), 4.73–4.69 (m, 2H, 2CHHPh), 4.65 (d, 1H, J = 11.8 Hz,
CHHPH), 4.63–4.57 (m, 2H, H-1A0, CHHPH), 4.43–4.38 (m, 2H, H-
1B, CHHPh), 4.28 (dd, 1H, J = 5.0, 10.6 Hz, H-6A0a), 4.20 (m, 1H,
H-5C), 4.11–4.02 (m, 3H, H-3A, H-2C, H-6Ba), 3.96 (dd, 1H,
J = 6.9, 11.1 Hz, H-6Bb), 3.89–3.82 (m, 4H, H-4A, H-6Aa, H-3C, H-
2A0), 3.79–3.65 (m, 4H, H-6Ab, H-4A0, H-6A0b, OCHHCH2), 3.62
(dd, 1H, J = 3.7, 10.0 Hz, H-3B), 3.60–3.47 (m, 5H, H-2A, H-5A, H-
5B, H-4C, H-5A0), 3.45 (t, 2H, J = 6.7 Hz, CH2Cl), 3.34 (m, 1H,
OCHHCH2), 2.03, 1.99, 1.93 (3s, 9H, 3OCOCH3), 1.76 (s, 3H,
NHCOCH3), 1.66 (m, 2H, O(CH2)4CH2CH2Cl), 1.45 (m, 2H,
OCH2CH2(CH2)3CH2Cl), 1.33 (m, 2H, O(CH2)3CH2(CH2)2Cl), 1.23
(m, 2H, O(CH2)2CH2(CH2)3Cl), 1.18 (s, 9H, C(CH3)3), 1.12 (d, 3H,
J = 6.5 Hz, H-6C). 13C NMR (125 MHz, CDCl3, 295 K): dC 177.7,
171.4, 170.1, 169.8, 169.0, 162.0 (C@O), 139.0, 138.9, 138.5,
138.1, 136.8 (quat Ar), 129.2, 128.4, 128.3, 128.2, 127.8, 127.6,
127.5, 127.3, 127.0, 126.1 (Ar), 101.4 (˜CHPh), 100.5 (C-1A0), 99.6
(C-1A), 99.3 (C-1B), 96.8 (C-1C), 92.2 (CCl3), 79.7 (C-3C), 78.3
(C-4A0), 77.2 (C-4C), 76.5 (C-2C), 74.5 (C-3B), 74.4 (CH2Ph), 74.2
(C-5A), 73.6 (C-4A), 73.5 (CH2Ph) 73.2 (CH2Ph), 72.8 (C-3A), 72.6
(CH2Ph), 71.1 (C-2B), 70.8 (C-5B), 70.6 (C-3A0), 69.2 (OCH2CH2),
68.8 (C-6A), 68.6 (C-4B), 68.2 (C-6A0), 66.6 (C-5A0), 66.4 (C-5C),
61.1 (C-6B), 56.4 (C-2A0), 54.6 (C-2A), 45.0 (CH2Cl), 38.7
(C(CH3)3), 32.5 (O(CH2)4CH2CH2Cl), 29.2 (OCH2CH2(CH2)3CH2Cl),
27.1 (C(CH3)3), 26.6 (O(CH2)3CH2(CH2)2Cl), 25.2 (O(CH2)2CH2
(CH2)3Cl), 23.1 (NHCOCH3), 21.0, 20.8, 20.7 (OCOCH3), 16.6 (C-
6C). HRESIMS calcd for C80H99Cl4N2O24 [M+H]+ 1611.5342, found:
1611.5304.
C
65H87Cl4N2O28 [M+H]+ 1483.4199, found: 1483.4148.
1.8. 6-Chlorohexyl 2-acetamido-4-O-[2,4-di-O-acetyl-6-O-piva-
loyl-3-O-(4,6-O-benzylidene-3-O-acetyl-2-deoxy-2-trichloroace-
tamido-b-D-glucopyranosyl)-b-D-galactopyranosyl]-6-O-benzyl-
3-O-(2,3,4,6-tetra-O-acetyl-b-
D
-galactopyranosyl)-2-deoxy-b-
D-
glucopyranoside (11)
Tetrasaccharide 10 (8.5 mg, 5.708 lmol) was acetylated as de-
scribed for compound 5 and isolated without column chromatog-
raphy to give 11 pure (8.7 mg, quant) as a colorless amorphous
glass. [a]
ꢂ25.5 (c 0.9, CH2Cl2), 1H NMR (CDCl3, 600 MHz,
D
296 K): dH 7.43–7.40 (m, 2H, Ar), 7.36–7.26 (m, 8H, Ar), 6.99 (d,
1H, J = 7.0 Hz, NHA0), 6.36 (d, 1H, J = 9.4 Hz, NHA), 5.50 (s, 1H,
˜CHPh), 5.38 (d, 1H, J = 3.3 Hz, H-4C), 5.35 (t, 3H, J = 10. 0 Hz, H-
3A0), 5.29 (d, 1H, J = 3.2 Hz, H-4B), 5.15 (br t, 1H, JH-2,H-1 + JH-2,H-
3 = 18.3 Hz, H-2C), 5.05 (dd, 1H, J = 2.9, 10.3 Hz, H-3C), 4.97 (t,
1H, J = 8.6 Hz, H-2B), 4.88 (d, 1H, J = 7.8 Hz, H-1C), 4.67 (d, 1H,
J = 8.0 Hz, H-1A0), 4.59 (d, 1H, J =11.5 Hz, CHHPh), 4.50 (d, 1H,
J = 11.4 Hz, CHHPh), 4.32–4.27 (m, 2H, H-1B, H-6A0a), 4.24 (d, 1H,
J = 4.3 Hz, H-1A), 4.18 (dd, 1H, J = 8.5, 10.9 Hz, H-6Ba), 4.12–4.03
(m, 5H, H-2A, H-3A, H-6Bb, H-6Cab), 3.98–3.93 (m, 2H, H-5B, H-
5C), 3.87 (m, 1H, H-2A0), 3.79–3.62 (m, 8H, H-4A, H-5A, H-6Aab,
H-3B, H-4A0, H-6A0b, OCHHCH2), 3.56–3.49 (m, 3H, H-5A0,CH2Cl),
3.29 (m, 1H,OCHHCH2), 2.15, 2.07, 2.03, 2.01, 1.95, (7s, 21H,
7OCOCH3), 2.00 (s, 3H, NHCOCH3), 1.74 (m, 2H, O(CH2)4CH2CH2Cl),
1.52 (m, 2H, OCH2CH2(CH2)3CH2Cl), 1.40 (m, 2H, O(CH2)3CH2
(CH2)2Cl), 1.30 (m, 2H, O(CH2)2CH2(CH2)3Cl), 1.19 (s, 9H, C(CH3)3).
13C NMR (125 MHz, CDCl3, 296 K): dC 177.7, 171.4, 170.4, 170.3,
170.2, 169.9, 169.7, 162.0 (C@O), 138.3, 136.7 (quat Ar), 129.3,
128.4, 128.3, 127.9, 127.8, 126.0 (Ar), 101.4 (˜CHPh), 100.9 (C-
1A0), 100.5 (C-1A), 98.6 (C-1B, C-1C), 92.2 (CCl3), 78.3 (C-4A0),
75.6 (C-5C), 75.5 (C-5A), 74.5 (C-3B), 73.5 (CH2Ph), 72.3 (C-3A),
71.4 (C-2B), 71.1 (C-4A), 70.8 (C-5B), 70.7 (C-3C), 70.5 (C-3A0),
70.1 (C-6A), 69.1 (OCH2CH2), 68.4 (C-4B, C-2C), 68.2 (C-6A0), 67.0
(C-4C), 66.5 (C-5A0), 60.6 (C-6C, C-6B), 56.5 (C-2A0), 49.2 (C-2A),
45.0 (CH2Cl), 38.7 (C(CH3)3), 32.4 (O(CH2)4CH2CH2Cl), 29.2
(OCH2CH2(CH2)3CH2Cl), 27.1 (C(CH3)3), 26.6 (O(CH2)3CH2(CH2)2Cl),
25.3 (O(CH2)2CH2(CH2)3Cl), 23.1 (NHCOCH3), 21.5, 20.9, 20.8, 20.7,
20.6 (OCOCH3). HRESIMS calcd for C67H89Cl4N2O29 [M+H]+
1525.4305, found: 1525.4380.
1.7. 6-Chlorohexyl 2-acetamido-4-O-[2,4-di-O-acetyl-6-O-piva-
loyl-3-O-(4,6-O-benzylidene-2-deoxy-2-trichloroacetamido-b-
D
-glucopyranosyl)-b-
D-galactopyranosyl]-6-O-benzyl-3-O-(2,3,
4,6-tetra-O-acetyl-b-
D
-galactopyranosyl)-2-deoxy-b- -gluco-
D
pyranoside (10)
Trisaccharide acceptor 1 (30.0 mg, 0.0260 mmol, 1 equiv) and
galactosyl bromide 9 (53.9 mg, 0.130 mmol, 5 equiv) were dis-
solved in a 1:1 mixture of dry PhMe and MeNO2 (2 mL) containing
powdered molecular sieves 4 Å (400 mg) and the mixture was stir-
red for 3 h at rt under N2. Then Hg(CN)2 (39.4 mg, 0.156 mmol,
6 equiv) was added and the reaction was heated to 50 °C for 5 h.
The reaction mixture was filtered over CeliteÒ and the solids were
washed with CH2Cl2 (2 ꢁ 25 mL). The combined filtrate and wash-
ings were washed with saturated aq NaHCO3 (1 ꢁ 50 mL) and the
aq layer was re-extracted with CH2Cl2 (3 ꢁ 15 mL). The combined
organic layers were dried and concentrated. The product was puri-
fied by column chromatography (4:6–5:5 EtOAc–hexanes) to give
tetrasaccharide 10 (25.8 mg, 67%) as a white amorphous foam.
[
a
]
ꢂ30.0 (c 1.0, CH2Cl2), 1H NMR (CDCl3, 600 MHz, 295 K): dH
D
7.46–7.43 (m, 2H, Ar), 7.37–7.26 (m, 8H, Ar), 6.99 (d, 1H,
J = 7.1 Hz, NHA0), 6.38 (d, 1H, J = 9.5 Hz, NHA), 5.52 (s, 1H, ˜CHPh),
5.37 (d, 1H, J = 3.2 Hz, H-4C), 5.33 (d, 1H, J = 3.4 Hz, H-4B), 5.20 (d,

138
M. Guillemineau, F.-I. Auzanneau / Carbohydrate Research 357 (2012) 132–138
4. Spijker, N. M.; van Boeckel, A. A. Angew. Chem., Int. Ed. Engl. 1991, 30, 180–
Acknowledgments
183.
5. Masamune, S.; Choy, W.; Petersen, J. S.; Sita, L. R. Angew. Chem., Int. Ed. Engl.
1985, 24, 1–30.
6. Analytical data for trisaccharide 1 are given below; its chemical synthesis will
be described in a future publication.
7. Fraser-Reid, B.; Wu, Z.; Andrews, C. W.; Skowronski, E.; Bowen, J. P. J. Am. Chem.
Soc. 1991, 113, 1434–1435; Andrews, C. W.; Rodebaugh, R.; Fraser-Reid, B. J.
Org. Chem. 1996, 61, 5280–5289; Jensen, H. H.; Nordstrom, L. U.; Bols, M. J. Am.
Chem. Soc. 2004, 126, 9205–9213; Crich, D. Acc. Chem. Res. 2010, 43, 1144–
1153; Aubry, S.; Sasaki, K.; Sharma, I.; Crich, D. In Reactivity Tunning in
Oligosaccharide Assembly; Fraser-Reid, B., López, J. C., Eds.; Topics in Current
Chemistry 301; Springer-Verlag: Berlin, Germany, 2011; pp 141–
188.
The authors are grateful for financial support by NSERC.
Supplementary data
Supplementary data (1H and 13C spectra for compounds 1, 2, 4–
8, 10, 11) associated with this article can be found, in the online
version, at http://dx.doi.org/10.1016/j.carres.2012.04.020.
References
ˇ
8. Lönn, H. Carbohydr. Res. 1985, 139, 105–113; Ruttens, B.; Kovác, P. Synthesis
2004, 15, 2505–2508.
1. Bohé, L.; Crich, D. Trends Glycosci. Glycotechnol. 2010, 22, 1–15.
2. Fraser-Reid, B.; López, J. C.; Radhakrishnan, K. V.; Mach, M.; Schlueter, U.;
Gomez, A.; Uriel, C. Can. J. Chem. 2002, 80, 1075–1087; Fraser-Reid, B.; López, J.
C.; Gomez, A. M.; Uriel, C. Eur. J. Org. Chem. 2004, 7, 1387–1395; Fraser-Reid, B.;
López, J. C. In Reactivity Tunning in Oligosaccharide Assembly; Fraser-Reid, B.,
López, J. C., Eds.; Topics in Current Chemistry 301; Springer-Verlag: Berlin,
Germany, 2011; pp 1–29.
9. Hendel, J. L.; Auzanneau, F.-I. Eur. J. Org. Chem. 2011, 34, 6864–6876.
10. Wang, A.; Hendel, J. L.; Auzanneau, F.-I. Beilstein J. Org. Chem. 2010, 6. article 17,
doi:http://dx.doi.org/10.3762/bjoc.6.17; Hendel, J. L.; Cheng, A.; Auzanneau, F.-
I. Carbohydr. Res. 2008, 343, 2914–2923.
11. Kartha, K. P. R.; Jennings, H. J. J. Carbohydr. Chem. 1990, 9, 777–781.
12. Liao, L.; Auzanneau, F.-I. Org. Lett. 2003, 5, 2607–2610; Liao, L.; Robertson, V.;
ˇ
Auzanneau, F.-I. Carbohydr. Res. 2005, 340, 2826–2832; Ruttens, B.; Kovác, P.
Carbohydr. Res. 2006, 341, 1077–1080.
3. Fraser-Reid, B.; Lopez, J. C.; Radhakrishnan, K. V.; Mach, M.; Schlueter, U.;
Gomez, A. M.; Uriel, C. J. Am. Chem. Soc. 2002, 124, 3198–3199.