Efficient synthesis of O-antigen fragments expressed by Burkholderia anthina by modular synthesis approach

Article abstract of DOI:10.1016/j.carres.2014.11.005

To facilitate mapping of the interaction region of the O-chain of the lipopolysaccharide from Burkholderia anthina and of a lipopolysaccharide-specific monoclonal antibody, trisaccharide propyl α-l-rhamnopyranosyl-(1→2)-α-d-galactopyranosyl-(1→3)-α-l-rham

Full text of DOI:10.1016/j.carres.2014.11.005

Carbohydrate Research 404 (2015) 98–107
Contents lists available at ScienceDirect
Carbohydrate Research
journal homepage: www.elsevier.com/locate/carres
Efficient synthesis of O-antigen fragments expressed by Burkholderia
anthina by modular synthesis approach
Inga Nilsson a, Dirk Michalik a,b, Alba Silipo c, Antonio Molinaro c, Christian Vogel a,
⇑
a University of Rostock, Institute of Chemistry, Albert-Einstein-Strasse 3a, D-18059 Rostock, Germany
b Leibniz Institute for Catalysis at the University of Rostock, Albert-Einstein-Str. 29a, D-18059 Rostock, Germany
c Department of Chemical Sciences, University of Naples ‘Federico II’, I-80126—Via Cinthia 4, Napoli, Italy
a r t i c l e i n f o
a b s t r a c t
Article history:
Received 12 June 2014
Received in revised form 30 October 2014
Accepted 17 November 2014
Available online 29 November 2014
To facilitate mapping of the interaction region of the O-chain of the lipopolysaccharide from Burkholderia
anthina and of a lipopolysaccharide-specific monoclonal antibody, trisaccharide propyl -rhamnopyr-
-rhamnopyranoside (27) and hexasaccharide propyl
-galactopyranosyl-(1?3)- -rhamnopyranosyl-(1?2)- -rhamnopyr-
-galactopyranosyl-(1?3)- -rhamnopyranoside (33) were synthesized. These
a
-L
anosyl-(1?2)-
a
-
-
D
-galactopyranosyl-(1?3)-
a
-
L
a
-L-rhamnopyranosyl-(1?2)-
a
-D
a-L
a-L
anosyl-(1?2)-
a
D
a-L
oligosaccharides represent the repeating monomer and dimer of the O-antigen, respectively.
Ó 2014 Elsevier Ltd. All rights reserved.
Keywords:
D-Galactose
L-Rhamnose
Oligosaccharides
O-Antigen
Burkholderia anthina
Glycosylation
1. Introduction
be obtained. In this multidisciplinary approach, the chemical syn-
thesis of the oligosaccharides was our task.
Gram-negative bacteria like Burkholderia anthina belonging to
the Burkholderia cepacia complex are human opportunistic patho-
gens responsible for lung infections in immunocompromised
patients, such as those with cystic fibrosis.1 Obviously, lipopolysac-
charides (LPSs) of B. cepacia complex are pivotally involved in the
mechanism of bacterial invasion and virulence.2 As a rule such LPSs
consist of a lipid A, a conserved core oligoheterosaccharide region,
and an antigenic O-specific polysaccharide chain. The O-antigen
structure of B. anthina has been determined by GC–MS and meth-
ylation analysis plus different NMR techniques as shown earlier:3
2. Results and discussion
The target of this project was not to develop new synthetic
methods but to apply the known chemistry for the efficient synthe-
sis of oligosaccharides. Retrosynthetic analysis of the repeating
unit described above illustrates that the key connection for a
blockwise oligosaccharide synthesis is the glycosidic linkage
between both of the
a trisaccharide module having
attached with two -rhamnose units serving either as acceptor or
as donor moieties at both ends of the molecule (Fig. 1).
Thus, higher oligosaccharides would be obtained by
L-rhamnose units. This strategy would require
D
-galactose located in the center
[?3)-a-L-Rha-(1?2)-a-L-Rha-(1?2)-a-D-Gal-(1?]n
L
To understand more about the pathogenic mechanisms, the
interaction between this O-polysaccharide chain and a lipopoly-
saccharide specific monoclonal antibody has been studied using
high resolution NMR spectroscopy.4 With in this framework, tri-
saccharide and hexasaccharide O-antigen repeating units have
been synthesized as simpler carbohydrate ligands. In addition
molecular dynamic simulations on the saccharides have been car-
ried out. The synthesis and dynamics studies allow for more
detailed information about the molecular recognition process to
a-glycosyl-
ation of a manno-configured donor. The formation of this type of
1,2-trans glycosidic bond is characterized by high stereoselectivity
caused by the anomeric effect and by using intramolecular neigh-
boring group participation of acyl groups at the C-2 hydroxyl
group, especially.
By taking advantage of difference in reactivities of acetyl and
benzoyl esters we utilized benzoyl and benzyl functions as perma-
nent and acetyl and allyl functions as temporary protecting groups.
Our initial task was the synthesis of suitable
which allowed either as donor the stereoselective formation of
the required -(1?2)-glycosidic bond to -galactose, or as
L-rhamnose units
⇑
Corresponding author.
E-mail address: christian.vogel@uni-rostock.de (C. Vogel).
a
D
http://dx.doi.org/10.1016/j.carres.2014.11.005
0008-6215/Ó 2014 Elsevier Ltd. All rights reserved.

I. Nilsson et al. / Carbohydrate Research 404 (2015) 98–107
99
OAll
3,4-O-dibenzyl derivative 910 which gave after acetylation of the
C-2 hydroxyl group the glycosyl donor 10.
O
O
BnO
O
The acetylation at the O-2 position of compound 9 caused a sig-
nificant downfield shift of the H-2 signal from d 4.19 to d 5.61 ppm
in the 1H NMR spectrum of compound 10. Again, the observed
13C–1H coupling constant 1JC-1,H-1 = 169 Hz confirmed the assigned
O
O
AcO
OBz
BnO
BnO
a
configuration.
BzO
OBn
Basically, this pathway can also be applied to the synthesis of
OBz
acceptor 5. Thus, isopropylidenation of compound 1 followed by
successive benzylation, deisopropylidenation, formation of cyclic
orthoester and its regioselective opening provided acceptor 5 as
described by Pinto et al.11 But, compared to the former pathway
the overall yield was significantly lower (57%) and the total
number of synthetic steps twice as high.
Figure 1.
acceptor the
a
-(1?3)-linkage by D-galactose. For the synthesis of a
rhamnosyl acceptor, allyl
a-L
-rhamnopyranoside 15 was regiose-
lectively protected as an orthoester (3)6 followed by benzylation
of the C-4 hydroxyl group.7 Treatment of the fully protected deriv-
ative 4 with dilute acid gave, regioselectively, the intermediate
where the C-2 hydroxyl group was protected as a benzoyl ester
while its C-3 hydroxyl group remained unprotected (5, Scheme 1).
So, acceptor 5 was obtained in 86% overall yield, which is calcu-
lated based on compound 1.
Furthermore, the rhamnose donor 1712 was synthesized start-
ing from tetraacetate 11 which was transformed via bromide 12
into the cyclic 1,2-orthoester 13. Consecutive treatment of 13 with
potassium hydroxide and benzyl chloride furnished 3,4-dibenzyl
orthoester 15.13 Exposure of the cyclic orthoester to aqueous acetic
acid, removal of the solvent from the reaction mixture, and
treatment of the residue with acetic anhydride provided derivative
That regioselective ring opening of orthoester 4 had occurred
was proven by 1H NMR data obtained. As expected, the benzoyl
substituent at O-2 caused a considerable downfield shift of the
H-2 signal from d 3.94 ppm of compound 1 to d 5.39 ppm in the
spectrum of 5. The stereochemistry at the anomeric center was
16 as
a/b-mixture of O-acetates. This second glycosyl donor
synthesis gave finally bromide 17 by treatment of 16 with oxalyl
bromide in 49% yield over seven steps starting from L-rhamnose
tetraacetate 11.
The next task was to synthesize a D-galactose donor and assem-
1
evident from the 13C–1H coupling constant JC-1,H-1 = 171 Hz
ble the galactose-rhamnose unit. After formation of the disaccha-
ride, the deprotected C-20 hydroxyl group of galactose residue
should serve as an acceptor to furnish the desired trisaccharide
module 25. The galactose unit preparation began by reaction of
confirming the proposed
a
configuration.
The
L-rhamnose donor synthesis was based on procedures from
the literature and began with thioglycoside 28 by selective protec-
tion of the hydroxyl groups at C-2 and C-3 as the acetonide (6) fol-
lowed again by benzylation of the C-4 hydroxyl group.9 After
removal of the isopropylidene group from 7, regioselective
mono-benzylation by the stannylation methodology provided
known phenyl b-D
-thiogalactopyranoside14 with 2,2-dimethoxy-
propane to form the diacetal 1815 (Scheme 2) followed by protec-
tion of the C-2 hydroxyl group as p-methoxybenzyl ether. Exposure
of the fully protected intermediate to camphorsulfonic acid
R
OAll
OAll
i
O
iii
O
O
HO
RO
BnO
HO
O
HO
OH
O
OBz
Ph
OEt
3 R = H (from 1)
4 R = Bn
1 R = OAll
2 R = SPh
5
ii
iv
SPh
SPh
O
SPh
vi
O
viii
RO
O
BnO
BnO
R2O
O
BnO
OR1
O
OAc
8 R1 = R2 = H
9 R1 = H R2 = Bn
6 R = H (from 2)
7 R = Bn
10
v
vii
R
R
x
xiii
O
AcO
O
O
O
RO
BnO
AcO
RO
CH3
OAc
BnO
O
OAc
OEt
11 R = OAc
12 R = Br
16 R = α/β OAc (from 15)
17 R = Br
13 R = OAc (from 12)
14 R = H
ix
xiv
xi
xii
15 R = Bn
Scheme 1. (i) Camphorsulfonic acid, triethylorthobenzoate, DMF, 2 h, 0?20 °C; (ii) BnBr, NaH, DMF, 18 h, 0?20 °C; (iii) 50% aq acetic acid, 30 min, 20 °C (5, 86% over three
steps); (iv) camphorsulfonic acid, 2,2-dimethoxypropane, acetone, 1 h, 20 °C; (v) BnBr, NaH, DMF, 16 h, 0?20 °C; (vi) 90% aq acetic acid, 3 h, 90 °C (8, 87% over three steps);
(vii) dibutyltin oxide, benzene, 5 h, reflux; then CsF, BnBr, DMF, 2 h, 20 °C (9, 75%); (viii) Ac2O, pyridine, 1 h, 0?20 °C (10, 91%); (ix) 40% HBr, CHCl3, 1 h, 0?20 °C; (x) 2,6-
lutidine, n-Bu4NBr, EtOH, CH2Cl2, 18 h, 20 °C (13, 92% over two steps); (xi, xii) KOH, BnBr, toluene, 45 min, reflux (15, 82%); (xiii) 70% aq acetic acid, 10 min, 20 °C, ultrasonic
bath; then Ac2O, pyridine, 1 h, 0?20 °C (16a, 66%; 16b, 15%); oxalyl bromide, CH2Cl2, 2 h, ꢀ40?20 °C, Ar atmosphere (8, 85%).

100
I. Nilsson et al. / Carbohydrate Research 404 (2015) 98–107
O
R2O
R1O
O
OR3
OMe
BzO
BzO
OBn
O
i
O
iv
O
SPh
O
SPh
SPh
HO
PMBO
PMBO
19 R1 R2 = C(CH3)2 R3 = H
20 R1 R2 = C(CH3)2 R3 = Bn
21 R1 = R2 = H R3 = Bn
18
22 (from 21)
ii
iii
Scheme 2. (i) p-Methoxybenzyl bromide, NaH, DMF, 16 h, 0?20 °C; then camphorsulfonic acid, MeOH, 10 min, 20 °C (19, 80%); (ii) BnBr, NaH, DMF, 16 h, 0?20 °C (20, 81%);
(iii) camphorsulfonic acid, MeOH, 14 h, 20 °C (21, 79%); (iv) BzCl, pyridine, 16 h, 0?20 °C (22, 98%).
effected the removal of the aliphatic acetal at the C-6 hydroxyl
group (19).16 Consecutive benzylation (20), deisopropylidenation
(21), and benzoylation gave the galactose module 22 in 50% yield
over six steps.
with NIS/AgOTf17 in CH2Cl2 at ꢀ20?20 °C. The glycosylation reac-
tion was complete within 30 min. Under these conditions disac-
charide 23 was obtained in excellent 89% yield (Scheme 3). The
acceptor disaccharide 24 was then prepared by oxidative cleavage
of the p-methoxybenzyl ether linkage using cerium ammonium
nitrate (CAN)18 which gave quite a better yield (85%) than 2,3-
dichloro-5,6-dicyano-1,4-benzoquinone (DDQ)19 (58%).
Detailed NMR investigation of compounds 19, 20, 21, and 22
verified the expected structures. First, the benzylation of the O-6
position caused a significant downfield shift of the C-6 signal in
the 13C NMR spectrum from d 62.6 to d 69.7 ppm in the spectrum
of compound 20. The deisopropylidenation of compound 20 led to
an upfield shift of H-3 and H-4 signals in the 1H NMR spectrum and
C-3 and C-4 signals in the 13C NMR spectrum, respectively. The
benzoylation of O-3 and O-4 positions caused again a significant
downfield shift of the H-3 and H-4 proton signals from 3.61 ppm
(H-3) and 3.75 ppm (H-4) to 5.87 ppm (H-3) and 5.43 ppm (H-4)
in the 1H NMR spectrum of donor 22. The vicinal coupling constant
3JH-1,H-2 = 9.6 Hz is consistent with the b configuration.
The coupling constant of 3JH-1 ,H-2 = 3.5 Hz in the 1H NMR spec-
trum of disaccharide 23 indicated clearly the linkage between
0
0
a
the D-galactose and the L-rhamnose residue. After the debenzyla-
tion at the O-20 position, the NMR data confirmed the proposed
structure of compound 24.
Although we expected a high stereoselectivity during the for-
mation of the L-Rha-(1?2)-a-D-Gal linkage, we systematically
examined the trisaccharide synthesis by applying the potential
rhamnopyranosyl donors 10, 16, and 17. Thus, disaccharide
acceptor 24 was glycosylated with rhamnosyl bromide 17 in the
presence of Helferich promotors20 to give trisaccharide 25 in
For the synthesis of galactosyl-rhamnose disaccharide 23, cou-
pling of thioglycoside 22 and rhamnose acceptor 7 was promoted
R1
1
OAll
5
6
5
O
3
R2O
6
1
O
3
10 (iii)
16 (iv)
+
+
+
2
BnO
4
O
O
2'
R4O
1'
OR3
2
1''
4
2''
O
17
(v)
i
1'
OBz
22
+
5
RO
O
O
3''
2'
3'
R2O
O
5''
5'
6'
3'
4''
R3O 4'
OR2
5'
R2O
6''
BzO
OBn
6'
OR3
4'
OBz
25 R1 = OAll R2 = Bn R3 = Bz R4 = Ac
26 R1 = OAll R2 = Bn R3 = R4 = H
27 R1 = O(CH2)2CH3 R2 = R3 = R4 = H
vi
23 R = PMB
24 R = H
ii
viii
vii
1
2
3
R =
1 = OC(=NPh)CF3 R2 = Bn R3 = Bz R4 = Ac
OH R = Bn R = Bz R4 = Ac
α β
,
28
29
ix
x
R
30 R1 = OAll R2 = Bn R3 = Bz R4 = H
xi
A
R1
5
1
R2O6
O
B
3
2
4
O
O
5
6
4
OR3
1''
1'
O
1
R2O
2''
3
R4O
O2
2''
O
1''
2'
O
3''
O
1'
3'
R2O
5'
6'
O
2'
R3O
5''
3''
O
R2O
4''
R3O4'
OR2
R2O
3'
4''
6''
5''
O
OR3
31 R1 = OAll R2 = Bn R3 = Bz R4 = Ac (from 29 + 30)
R2O R3O
5'
6''
4'
OR2
6'
OR3
xii
R = OAll R = Bn R3 = R4 = H
1
2
32
xiii
33 R1 = O(CH2)2CH3 R2 = R3 = R4 = H
Scheme 3. (i) NIS, AgOTf, mol. sieves, CH2Cl2, Ar atmosphere, 20 min, ꢀ10?20 °C (23, 89%); (ii) CAN, CH3CN–H2O, 3 h, 20 °C (85%); (iii) NIS, AgOTf, mol. sieves, Ar
atmosphere, CH2Cl2, 1 h, ꢀ20?20 °C (25, 66%); (iv) TMSOTf, mol. sieves, Ar atmosphere, CH2Cl2, 36 h, 20 °C (25, 61%); (v) Hg(CN)2, HgBr2, CH3CN, mol. sieves, Ar atmosphere,
in the dark, 24 h, 20 °C (25, 35%); (vi) NaOMe, MeOH, 24 h, 20 °C (26, 74%); (vii) Pd(OH)2/C, MeOH, H2 atmosphere, 48 h, 20 °C (27, 94%); (viii) PdCl2, MeOH–CH2Cl2, 16 h,
20 °C; (ix) ClC(@NPh)CF3, CsCO3, acetone, 3 h, 20 °C (29, 87% over two steps); (x) methanolic HCl, 18 h, 20 °C (30, 74%); (xi) TMSOTf, mol. sieves, Ar atmosphere, CH2Cl2,
30 min, ꢀ10 to 20 °C (31, 53%); (xii) NaOMe, MeOH, 43 h, 20 °C (32, 76%); (xiii) Pd(OH)2/C, MeOH–H2O, H2 atmosphere, 72 h, 20 °C (33, 93%).

I. Nilsson et al. / Carbohydrate Research 404 (2015) 98–107
101
disappointing 35% yield. However, when 1-O-acetate 16 was used
as donor promoted by trimethylsilyl trifluoromethanesulfonate,21
25 was obtained in promising 61% yield. The best result was
observed when thioglycoside 10 was coupled with 24 by treatment
with NIS/AgOTf17 to provide the desired trisaccharide 25 in 66%
yield. As anticipated, the manno-configuration and the neighboring
effect of O-2 ester function directed the glycosylation to give only
NaHCO3 and NaCl solutions were saturated. Reactions were moni-
tored by thin-layer chromatography (TLC; Silica Gel 60, F254
,
0.25 mm, Merck KGaA). The following solvent systems (v/v) were
used: (A1) 2:1, (A2) 1:1 n-heptane–EtOAc; (B1) 50:1, (B2) 15:1,
(B3) 1:1, (B4) 18:1, (B5) 2:3 toluene–EtOAc; (C1) 2:1 CHCl3–MeOH;
(D1) 4:0.5:0.5 acetonitrile–pyridine–H2O. TLC spots were made vis-
ible by dipping the TLC plates into an ethanolic 10% H2SO4 solution
and charring with a heat gun for 3–5 min. Detection of benzyl
derivatives was effected by UV fluorescence. Preparative flash
chromatography was performed by elution from columns of
the
a-linkage. The
a
configuration of the newly generated stereo-
genic center in the trisaccharide 25 was verified by 1D and 2D
NMR
spectroscopy.
The
13C–1H
coupling
constant
1
00
00
JC-1 ,H-1 = 169 Hz is consistent with the proposed
a
linkage.
slurry-packed Silica Gel 60 (Merck, 40–63 lm). All solvents and
Synthesis of either trisaccharide donor 29 or trisaccharide
acceptor 30 starting from module 25 was performed following pro-
cedures described previously by our group.5 Accordingly deallyla-
tion22 of 25 gave hemiacetal 28 which was treated with
(N-phenyl)trifluoroacetimidate chloride23 in the presence of Cs2-
CO3 in acetone to furnish (N-phenyl)trifluoroacetimidate 29.
The anomeric proton signal of donor 29 appeared as broadened
reagents were purified and dried according to standard proce-
dures.24 After classical work-up of the reaction mixtures, the
organic layers were dried over MgSO4 and then concentrated under
reduced pressure (rotary evaporator).
3.2. Allyl 2-O-benzoyl-4-O-benzyl-a-L-rhamnopyranoside (5)
at ambient temperature due to a dynamic process, but the coupling
Camphorsulfonic
ethylorthobenzoate (0.86 mL, 3.8 mmol) were successively added
to a solution of allyl
-rhamnopyranoside5 (1, 613 mg, 3.0 mmol)
acid
(117 mg,
0.5 mmol)
and
tri-
1
constant JC-1,H-1 = 174 Hz established the
a configuration of the
(N-phenyl)trifluoroacetimidate group at the anomeric center. On
the other hand, deacetylation of 25 with 0.28 m methanolic HCl5
provided acceptor 30 with only the O-200 position being unsubsti-
tuted. The successful cleavage of the acetyl group was confirmed
in the 1H NMR spectrum by a significant upfield shift for the
H-200 ring proton signal from d 5.09 ppm (25) to d 3.71 ppm (30).
The final task was to couple donor 29 with acceptor 30 to get
the hexasaccharide 31 and the global deprotection of both oligo-
saccharides 25 and 31 (Scheme 3). Using CF3SO3SiMe3 as promoter,
hexasaccharide 31 was obtained in 53% yield. Again, the stereo-
chemistry of the new glycosidic linkage of hexasaccharide 31
a-L
in dry N,N-dimethylformamide (30 mL) at 0 °C under an argon
atmosphere. The mixture was allowed to attain room temperature
and stirring was continued for 2 h. After complete reaction (3, TLC:
Rf = 0.73, EtOAc), the reaction mixture was neutralized with trieth-
ylamine (1 mL) and then cooled to 0 °C, followed by addition of
sodium hydride (178 mg, 7.4 mmol, 60% dispersion in oil) with vig-
orous stirring. The reaction mixture was stirred for 30 min at 0 °C,
followed by dropwise addition of benzyl bromide (0.5 mL,
4.2 mmol) at 0 °C. The mixture was allowed to attain room temper-
ature and stirring was continued for another 18 h. After complete
reaction (4, TLC: Rf = 0.76, solvent A1), MeOH (10 mL) was added
at 0 °C, and after stirring for additional 20 min, the reaction mix-
ture was concentrated. The residue was dissolved in CH2Cl2
(50 mL) and the organic solution was washed with water
(2 ꢂ 20 mL), dried and concentrated. The crude product was puri-
fied by flash chromatography (short column, Eluent EtOAc–hep-
tane 1:4 with 1% NEt3). The obtained syrup was dissolved in 50%
aq acetic acid (45 mL) and stirred 30 min at room temperature
(monitored by TLC). After complete reaction, satd NaHCO3
(10 mL) solution was added to the reaction mixture. The solution
was concentrated and repeatedly co-concentrated with toluene.
1
was evident from the 13C–1H coupling constant JC-1,H-1 = 169 Hz.
Deprotection of oligosaccharides 25 and 31 was accomplished by
Zemplén deacylation followed by catalytic hydrogenation to give
the propyl glycosides 27 and 33 in good yield.
In summary, we have developed an efficient synthesis of trisac-
charide module 25 which represents the repeating O-antigen
structure of B. anthina. Applying the methodology of modular
design principle5 higher fragments of the O-chain are accessible.
On this basis, hexasaccharide 31 was synthesized. After deprotec-
tion trisaccharide 27and hexasaccharide 33 were used for mapping
the interacting epitope with a monoclonal antibody and conforma-
tional studies on the bond state.4
The crude product was purified by flash chromatography (eluent
22
solvent A1) to give 5 (1.03 g, 86%) as a colorless syrup: [
a]
D
+5.3
(c 1.0, CHCl3), Lit.11
A1); NMR data see Ref. 11.
[a
]
D
+5.5 (c 0.9, CH2Cl2); Rf = 0.55 (solvent
25
3. Experimental
3.1. General methods
3.3. Phenyl 2-O-acetyl-3,4-di-O-benzyl-1-thio-a-L-
rhamnopyranoside (10)
Melting points were determined with a Boetius micro-heating
plate BHMK 05 (Rapido, Dresden) and were not corrected. Optical
rotations were measured for solutions in a 2-cm cell with an auto-
matic polarimeter GYROMAT (Dr. Kernchen Co.). 1H NMR spectra
(500.13 MHz, 300.13 MHz and 250.13 MHz) and 13C NMR spectra
(125.8 MHz, 75.5 MHz and 62.9 MHz) were recorded with Bruker
instruments AVANCE 500, AVANCE 300, and AVANCE 250, with
CDCl3, Me2SO-d6, CD3OD or D2O as solvents. NMR spectra were cal-
Acetyl anhydride (0.9 mL, 9.5 mmol) was added dropwise to a
stirred solution of phenyl 3,4-di-O-benzyl-1-thio-a-L-rhamnopyr-
anoside10 (9, 437 mg, 1.0 mmol) in dry pyridine (2 mL) under an
argon atmosphere at 0 °C. Then the reaction mixture was allowed
to attain room temperature and stirring was continued for 1 h.
After complete reaction (monitored by TLC), MeOH (100 lL) was
ibrated using solvent signals (CDCl3:
d
1H = 7.26 ppm,
d
added at 0 °C, and after stirring for additional 20 min, the reaction
mixture was poured into ice-water (80 mL). The aqueous phase
was extracted with CH2Cl2 (4 ꢂ 20 mL), and the combined organic
phases were washed successively with cold aq 15% NaHSO4
(2 ꢂ 30 mL), aq NaHCO3 (2 ꢂ 30 mL), water (1 ꢂ 50 mL), dried,
and concentrated. Purification by flash chromatography (solvent
13C = 77.00 ppm; Me2SO-d6: d 1H = 2.50 ppm, d 13C = 39.7 ppm;
CD3OD: d 1H = 3.31 ppm, d 13C = 49.0 ppm) or acetone as internal
standard (D2O: d 1H = 2.23 ppm, d 13C = 31.1 ppm). The 1H and
13C NMR signals were assigned by DEPT, two-dimensional 1H,1H
COSY and NOESY and 1H,13C correlation spectra (HMBC and HSQC).
For NMR numbering of atoms see Scheme 3. Mass spectra were
recorded with a Finnigan MAT 95-XP (Thermo Electron). Elemental
analysis was performed with a CHNS-Flash-EA-1112 instrument
(Thermoquest). All washing solutions were cooled to ꢁ5 °C. The
B1) afforded compound 10 (435 mg, 91%) as a colorless syrup:
[a
]
D
ꢀ117.2 (c 1.1, CHCl3); Rf = 0.25 (solvent B1); 1H NMR
22
(250.13 MHz, CDCl3): d 7.47–7.24 (m, 15H, 2 CH2C6H5, SC6H5);
5.61 (dd, 1H, J2,3 = 3.3 Hz, H-2); 5.41 (d, 1H, J1,2 = 1.6 Hz, H-1);
3
3

102
I. Nilsson et al. / Carbohydrate Research 404 (2015) 98–107
4.94, 4.63 (2d, 2H, 2J = 10.8 Hz), 4.72, 4.56 (2d, 2H, 2J = 11.2 Hz), (2
reaction (monitored by TLC), MeOH (10 mL) was added at 0 °C,
and after stirring for additional 20 min, the reaction mixture was
concentrated. The residue was dissolved in CH2Cl2 (50 mL) and
the organic solution was washed with water (2 ꢂ 20 mL), dried,
and concentrated. The crude product was purified by column chro-
3
3
CH2C6H5); 4.23 (dq, 1H, J4,5 = 9.5 Hz, J5,6 = 6.2 Hz, H-5); 3.91 (dd,
3
3
1H, J3,4 = 9.3 Hz, H-3); 3.52 (‘t’, 1H, J4,5 = 9.5 Hz, H-4); 2.15 (s,
3H, COCH3); 1.35 (d, 3H, J5,6 = 6.2 Hz, H-6); 13C NMR (62.9 MHz,
3
CDCl3): d 170.2 (COCH3); 138.3 137.7 (2 i-CH2C6H5); 133.9 (i-
SC6H5); 131.7, 129.0, 128.4, 128.4, 128.1, 127.9 (2 o-, m-CH2C6H5,
o-, m-SC6H5); 127.8, 127.7, 127.6 (2 p-CH2C6H5, p-SC6H5); 86.1
(C-1); 80.2 (C-4); 78.2 (C-3); 75.5, 71.8 (2ꢂ CH2C6H5); 70.6 (C-2);
69.1 (C-5); 21.0 (COCH3); 17.8 (C-6). HRMS (ESI-TOF): calcd for
matography (eluent gradient ethyl acetate in heptane 33?50%
23
with 1% NEt3) to give 20 (1.27 g, 81%) as a colorless syrup: [a]
D
ꢀ20.2° (c 1.0, CHCl3); Rf = 0.71 (solvent A2 with 1% NEt3); 1H
NMR (250.13 MHz, CDCl3): d 7.55 (m, 2H), 7.38–7.20 (m, 10H),
6.88 (m, 2H), (CH2C6H5, CH2C6H4, SC6H5); 4.76, 4.63 (2d, 2H,
2J = 11.0 Hz), 4.60, 4.53 (2d, 2H, 2J = 11.8 Hz), (CH2C6H5, CH2C6H4);
4.65 (d, 1H, J1,2 = 9.5 Hz, H-1); 4.28–4.20 (m, 2H, H-3, H-4); 3.94
(ddd, 1H, J4,5 = 5.9 Hz, J5,6a = 5.9 Hz, J5,6b = 1.8 Hz, H-5); 3.82–
C
28H30O5S (M+Na+): m/z 501.1706, found: m/z 501.1705. Anal.
Calcd for C28H30O5S (478.60): C, 70.27; H, 6.32; S, 6.70. Found: C,
70.18; H, 6.38; S, 6.58.
3
3
3
3
3
3.4. Phenyl 3,4-O-isopropylidene-2-O-p-methoxybenzyl-1-thio-
3.78 (m, 2H, H-6); 3.81 (s, 3H, OCH3); 3.53 (dd, 1H, J1,2 = 9.5 Hz,
b-
D
-galactopyranoside (19)
3J2,3 = 5.7 Hz, H-2); 1.43 (s, 3H), 1.36 (s, 3H), (C(CH3)2); 13C NMR
(62.9 MHz, CDCl3): d 159.3 (p-CH2C6H4); 138.2 (i-CH2C6H5); 134.0
(i-SC6H5); 130.0 (i-CH2C6H4); 131.7, 129.9, 128.7, 128.3, 127.6
(o-, m-CH2C6H5, o-CH2C6H4, o-, m-SC6H5); 127.6 (p-CH2C6H5);
127.2 (p-SC6H5); 113.7 (m-CH2C6H4); 110.0 (C(CH3)2); 86.3 (C-1);
79.6 (C-3); 77.9 (C-2); 75.7 (C-5); 73.8 (C-4); 73.1, 73.5 (CH2C6H5,
CH2C6H4); 69.7 (C-6); 55.3 (OCH3); 26.3, 27.8 (C(CH3)2). HRMS
(ESI-TOF): calcd for C30H35O6S (M+H+): m/z 523.2149, found: m/z
523.2144. Anal. Calcd for C30H34O6S (522.65): C, 68.94; H, 6.56;
S, 6.14. Found: C, 68.71; H, 6.73; S, 6.18.
A mixture of phenyl 1-thio-b-D
-galactopyranoside14 (1.09 g,
4.0 mmol), 2,2-dimethoxypropane (35 mL) and camphorsulfonic
acid (40 mg, 0.2 mmol) was stirred for 48 h under an argon atmo-
sphere at room temperature. After complete reaction (18, TLC:
Rf = 0.39, A2 with 1% NEt3), the reaction mixture was neutralized
with triethylamine (1.4 mL) and concentrated. The residue was
dissolved in dry N,N-dimethylformamide (27 mL) and cooled to
0 °C, followed by addition of sodium hydride (237 mg, 9.9 mmol,
60% dispersion in oil) with vigorous stirring. The reaction mixture
was stirred for 30 min at 0 °C, followed by dropwise addition of p-
methoxybenzyl bromide (0.82 mL, 5.6 mmol) at 0 °C. The mixture
was allowed to attain room temperature and stirring was contin-
ued for another 16 h. After complete reaction (TLC: Rf = 0.61, A2
with 1% NEt3), MeOH (5 mL) was added at 0 °C, and after stirring
for additional 20 min, the reaction mixture was concentrated.
The residue was dissolved in CH2Cl2 (50 mL) and the organic solu-
tion was washed with water (2 ꢂ 20 mL), dried, and concentrated.
A solution of the raw material and camphorsulfonic acid (29 mg,
0.1 mmol) in methanol (25 mL) was stirred for 10 min at room
temperature. After complete reaction (monitored by TLC), the reac-
tion mixture was neutralized with triethylamine (0.6 mL) and con-
centrated. The crude product was purified by flash
chromatography (eluent gradient ethyl acetate in heptane
3.6. Phenyl 6-O-benzyl-2-O-p-methoxybenzyl-1-thio-b-D-
galactopyranoside (21)
To a solution of compound 20 (540 mg, 1.0 mmol) in methanol
(56 mL) 10-camphorsulfonic acid (120 mg, 0.5 mmol) was added.
The mixture was stirred for 14 h at room temperature (monitored
by TLC). Then the solution was neutralized with NEt3 and concen-
trated. The residue was purified by flash chromatography (eluent
gradient ethyl acetate in heptane 33?100%) to afford compound
21 (396 mg, 79%) as colorless crystals: mp 103–106 °C (EtOAc–
25
heptane); [
a
]
+9.5 (c 1.0, CHCl3); Rf = 0.46 (EtOAc); 1H NMR
D
(250.13 MHz, DMSO-d6): d 7.48 (m, 2H), 7.37–7.17 (m, 10H), 6.87
3
(m, 2H), (CH2C6H5, CH2C6H4, SC6H5); 5.10 (d, 1H, J3,OH = 6.6 Hz,
3
OH-3); 4.81 (d, 1H, J4,OH = 4.5 Hz, OH-4); 4.78 (d, 1H,
20?50% with 1% NEt3) to give 19 (1.39 g, 80%) as a colorless syrup:
3J1,2 = 9.5 Hz, H-1); 4.70, 4.55 (2d, 2H, 2J = 10.6 Hz), 4.48 (s, 2H),
(CH2C6H5, CH2C6H4); 3.82–3.68 (m, 2H, H-4, H-5); 3.73 (s, 3H,
[a
]
+2.2 (c 1.0, CHCl3); Rf = 0.32 (solvent A2 with 1% NEt3); 1H
23
D
3
NMR (250.13 MHz, CDCl3): d 7.52 (m, 2H), 7.42–7.20 (m, 5H),
OCH3); 3.66–3.55 (m, 3H, H-3, H-6); 3.48 (‘t’, 1H, J2,3 = 9.3 Hz, H-
6.89 (m, 2H), (CH2C6H4, SC6H5); 4.77, 4.62 (2d, 2H, 2J = 11.0 Hz,
2); 13C NMR (62.9 MHz, DMSO-d6): d 158.6 (p-CH2C6H4); 138.5
(i-CH2C6H5); 135.1 (i-SC6H5); 131.0 (i-CH2C6H4); 129.6, 129.5,
129.0, 128.3, 127.5 (o-, m-CH2C6H5, o-CH2C6H4, o-, m-SC6H5);
127.5 (p-CH2C6H5); 126.5 (p-SC6H5); 113.5 (m-CH2C6H4); 86.0
(C-1); 77.8 (C-2); 77.3 (C-5); 74.5 (C-3); 73.9, 72.3 (CH2C6H5,
CH2C6H4); 70.0 (C-6); 69.5 (C-4); 55.2 (OCH3). HRMS (ESI-TOF):
calcd for C27H30O6S (M+Na+): m/z 505.1655, found: m/z 505.1658.
Anal. Calcd for C27H30O6S (482.59): C, 67.20; H, 6.27; S, 6.64.
Found: C, 67.04; H, 6.53; S, 6.68.
3
CH2C6H4); 4.65 (d, 1H, J1,2 = 9.3 Hz, H-1); 4.28 (‘t’, 1H,
3J3,4 = 6.0 Hz, H-3), 4.20 (dd, 1H, H-4); 3.96 (ddd, 1H, H-5); 3.87–
3
3.70 (m, 2H, H-6); 3.81 (s, 3H, OCH3); 3.53 (dd, 1H, J2,3 = 6.1 Hz,
H-2); 1.43 (s, 3H), 1.36 (s, 3H), (C(CH3)2); 13C NMR (62.9 MHz,
CDCl3): d 159.3 (p-CH2C6H4); 133.4 (i-SC6H5); 130.0 (i-CH2C6H4);
131.9, 129.9, 128.9 (o-CH2C6H4, o-, m-SC6H5); 127.5 (p-CH2C6H5);
127.2 (p-SC6H5); 113.7 (m-CH2C6H4); 110.3 (C(CH3)2); 85.9 (C-1);
79.8 (C-3); 77.9 (C-2); 76.7 (C-5); 73.9 (C-4); 73.1 (CH2C6H4);
62.6 (C-6); 55.3 (OCH3); 27.7, 26.3 (C(CH3)2). HRMS (ESI-TOF):
calcd for C23H28O6S (M+H+): m/z 433.5328, found: m/z 433.5329.
Anal. Calcd for C23H28O6S (432.53): C, 63.87; H, 6.52; S, 7.41.
Found: C, 63.78; H, 6.65; S, 7.29.
3.7. Phenyl 3,4-di-O-benzoyl-6-O-benzyl-2-O-p-methoxybenzyl-
1-thio-b-D-galactopyranoside (22)
Benzoyl chloride (0.65 mL, 5.6 mmol) was added dropwise to a
stirred solution of compound 21 (966 mg, 2.0 mmol) in dry pyri-
dine (10 mL) under an argon atmosphere at 0 °C. The reaction mix-
ture was stirred for 30 min at that temperature. The solution was
then allowed to attain room temperature and stirring was contin-
ued for further 16 h. After complete reaction (monitored by TLC),
MeOH (1 mL) was added at 0 °C, and after stirring for additional
20 min, the reaction mixture was poured into ice-water (100 mL).
The aqueous phase was extracted with CH2Cl2 (4 ꢂ 50 mL), and
the combined organic phases were washed successively with cold
aq 15% NaHSO4 (4 ꢂ 50 mL), aq NaHCO3 (2 ꢂ 50 mL), water
3.5. Phenyl 6-O-benzyl-3,4-O-isopropylidene-2-O-p-
methoxybenzyl-1-thio-b-D-galactopyranoside (20)
Sodium hydride (178 mg, 7.4 mmol, 60% suspension in oil) was
added to a stirred solution of compound 19 (1.3 g, 3.0 mmol) in dry
N,N-dimethylformamide (20 mL) under an argon atmosphere at
0 °C. The reaction mixture was stirred for 30 min at that tempera-
ture, followed by dropwise addition of benzyl bromide (0.5 mL,
4.2 mmol) at 0 °C. The mixture was allowed to attain room temper-
ature and stirring was continued for another 16 h. After complete

I. Nilsson et al. / Carbohydrate Research 404 (2015) 98–107
103
(2 ꢂ 50 mL), dried and concentrated. Purification by flash chroma-
tography (eluent gradient ethyl acetate in heptane 20?50%) affor-
68.0 (C-2); 67.1 (C-50); 55.1 (OCH3); 18.2 (C-6). HRMS (ESI-TOF):
calcd for C58H58O14 (M+Na+): m/z 1001.3719, found: m/z
1001.3748. Anal. Calcd for C58H58O14 (979.07): C, 71.15; H, 5.97.
Found: C, 70.67; H, 6.34.
ded compound 22 (1.36 g, 98%) as a colorless syrup: [a]
24 +107.8 (c
D
1.0, CHCl3); Rf = 0.49 (solvent A1); 1H NMR (300.13 MHz, CDCl3): d
7.92 (m, 2H), 7.78 (m, 2H), 7.69 (m, 2H), 7.63 (m, 1H), 7.52–7.42
(m, 3H), 7.36–7.17 (m, 10H), 7.08 (m, 2H), 6.65 (m, 2H), (2 COC6H5,
CH2C6H5, CH2C6H4, SC6H5); 5.87 (dd, 1H, 3J3,4 = 3.3 Hz, 3J4,5 = 1.0 Hz,
H-4); 5.43 (dd, 1H, 3J2,3 = 9.4 Hz, H-3); 4.84 (d, 1H, 3J1,2 = 9.6 Hz, H-
1); 4.73, 4.52 (2d, 2H, 2J = 10.4 Hz), 4.53, 4.43 (2d, 2H, 2J = 11.9 Hz),
3.9. Allyl 3,4-di-O-benzoyl-6-O-benzyl-a-D-galactopyranosyl-
(1?3)-2-O-benzoyl-4-O-benzyl- -rhamnopyranoside (24)
a-L
Cerium ammonium nitrate (CAN; 343 mg, 0.63 mmol) was
added to a stirred solution of compound 23 (490 mg, 0.5 mmol)
in acetonitrile–water (9:1, 10 mL). After stirring for 1 h at room
temperature, additional CAN (274 mg, 0.5 mmol) was added to
the solution. The mixture was stirred for additional 1 h and then
diluted with CH2Cl2 (75 mL). The solution was washed with aq
NaHCO3 (2 ꢂ 25 mL). The aq phase was extracted with CH2Cl2
(2 ꢂ 30 ml). The combined organic phases were dried, concen-
trated, and the residue was purified by flash chromatography (elu-
3
3
(CH2C6H5, CH2C6H4); 4.08 (d‘t’, 1H, J5,6a = 6.3 Hz, J5,6b = 6.3 Hz,
3J4,5 = 1.0 Hz, H-5); 3.96 (‘t’, 1H, H-2); 3.70 (dd, 1H, J6a,6b = 9.8 Hz,
2
3J5,6a = 6.3 Hz, H-6a); 3.69 (s, 3H, OCH3); 3.61 (dd, 1H, J6a,6b = 9.8
2
Hz, J5,6b = 6.3 Hz, H-6b); 13C NMR (75.5 MHz, CDCl3): d 165.3,
3
165.3 (2 COC6H5); 159.2 (p-CH2C6H4); 137.6 (i-CH2C6H5); 133.3,
133.0 (p-CH2C6H5); 133.0 (i-SC6H5); 132.5, 129.9, 129.8, 129.6,
129.0, 128.4, 128.3, 128.2, 127.7 (o-, m-CH2C6H5, o-CH2C6H4, 2 o-,
m-COC6H5, o-, m-SC6H5); 129.5, 129.5 (2 i-COC6H5); 127.7 (p-CH2
C6H5); 127.7 (p-SC6H5); 113.6 (m-CH2C6H4); 87.4 (C-1); 76.3
(C-5); 75.0 (C-3); 75.0, 73.6 (CH2C6H5, CH2C6H4); 74.8 (C-2); 69.1
(C-4); 68.2 (C-6); 55.1 (OCH3). HRMS (ESI-TOF): calcd for
ent gradient ethyl acetate in toluene 4?6%) to give compound 24
23
(365 mg, 85%) as a colorless syrup: [
a
]
+178.1 (c 1.1, CHCl3);
D
Rf = 0.35 (solvent B2); 1H NMR (500.13 MHz, CDCl3): d 8.09 (m,
2H), 7.99 (m, 2H), 7.84 (m, 2H), 7.62–7.57 (m, 2H), 7.50–7.43 (m,
6H), 7.34–7.24 (m, 5H), 7.22–7.13 (m, 6H), (2 CH2C6H5, 3 COC6H5);
C
41H38O8S (M+H+): m/z 713.2180, found: m/z 713.2188. Anal. Calcd
for C41H38O8S (690.80): C, 71.29; H, 5.54; S, 4.64. Found: C, 71.23;
H, 5.67; S, 4.59.
3
5.87 (m, 1H, CH2CH@CH2); 5.63 (dd, 1H, J2,3 = 3.2 Hz, H-2); 5.59
3
3
(dd, 1H, J3 ,4 = 3.3 Hz, H-40); 5.53 (dd, 1H, J2 ,3 = 10.4 Hz, H-30);
0
0
0
0
3
5.46 (d, 1H, J1 ,2 = 3.8 Hz, H-10); 5.32–5.18 (m, 2H, CH2CH@CH2);
4.94 (d, 1H, 3J1,2 = 1.9 Hz, H-1); 4.89, 4.84 (2d, 2H, 2J = 10.7 Hz, CH2
C6H5); 4.49–4.45 (m, 2H, H-3, H-50); 4.27 (d‘t’, 1H, H-20); 4.20 (cen-
ter of qAB, 2H, 2J = 12.1 Hz, CH2C6H5); 4.18 (m, 1H), 4.02 (m, 1H),
0
0
3.8. Allyl 3,4-di-O-benzoyl-6-O-benzyl-2-O-p-methoxybenzyl-
-galactopyranosyl-(1?3)-2-O-benzoyl-4-O-benzyl-
rhamnopyranoside (23)
a-
D
a-L-
3
Glycosyl acceptor 5 (398 mg, 1.0 mmol), donor 22 (829 mg,
1.2 mmol), and molecular sieves (4 Å, 7 g) were dried under high
vacuum for 1 h at room temperature. The solids were then sus-
pended in dry CH2Cl2 (75 mL), and the reaction mixture was stirred
for 30 min under an argon atmosphere in the dark at room temper-
ature. After cooling to ꢀ10 °C, NIS (515 mg, 2.3 mmol) and AgOTf
(309 mg, 1.2 mmol, dissolved in 1 mL dry toluene) were added
and the suspension was stirred for 10 min at ꢀ10 °C and then
20 min at room temperature. After complete reaction (monitored
by TLC), the reaction mixture was neutralized with NEt3 and fil-
tered through Celite. The filtrate was washed with cold aq 1 M Na2
S2O3 (2 ꢂ 30 mL) and aq NaCl (1 ꢂ 30 mL), dried, and concentrated.
Purification by flash chromatography (eluent gradient ethyl ace-
(CH2CH@CH2); 3.93 (dq, 1H, H-5); 3.65 (‘t’, 1H, J3,4 = 9.8 Hz,
3
3
J4,5 = 9.5 Hz, H-4); 3.46 (dd, 1H, J5 ,6a = 6.6 Hz, H-6a0); 3.29 (dd,
0
0
3
2
1H,
0
J5 ,6b = 6.0 Hz,
J6a ,6b = 10.1 Hz, H-6b0); 2.16 (d, 1H,
0
0
0
0
J2 ,OH = 9.5 Hz, OH-20); 1.48 (d, 3H, J5,6 = 6.2 Hz, H-6); 13C NMR
(125.8 MHz, CDCl3): d 166.4, 166.2, 165.4 (3 COC6H5); 138.0,
137.7 (2 i-CH2C6H5); 133.6, 133.2, 132.9 (3 p-COC6H5); 133.4 (CH2
CH@CH2); 129.9, 129.8 (2), 128.6, 128.6, 128.5, 128.1, 128.0 (2),
127.5 (2 o-, m-CH2C6H5, 3 o-, m-COC6H5); 129.7, 129.3 (2) (3 i-
COC6H5); 128.2, 127.3 (2 p-CH2C6H5); 117.9 (CH2CH@CH2); 96.7
(C-1); 95.2 (C-10); 80.0 (C-4); 73.6 (C-3); 76.1, 72.8 (2 CH2C6H5);
71.6 (C-30); 69.5 (C-40); 68.8 (C-2); 68.3 (C-5); 68.2 (CH2CH@CH2);
68.1 (C-60); 67.8 (C-50); 67.4 (C-20); 18.2 (C-6). HRMS (ESI-TOF):
calcd for C50H50O13 (M+Na+): m/z 881.3144, found: m/z 881.3139.
Anal. Calcd for C50H50O13 (858.92): C, 69.92; H, 5.87. Found: C,
69.63; H, 6.11.
3
3
0
tate in toluene 4?6%) gave compound 23 (870 mg, 89%) as a color-
22
less syrup: [
a]
+151.6 (c 1.0, CHCl3); Rf = 0.38 (solvent B2); 1H
D
NMR (500.13 MHz, CDCl3): d 8.07 (m, 2H), 7.84 (m, 2H), 7.70 (m,
2H), 7.60–7.52 (m, 4H), 7.47–7.39 (m, 5H), 7.35 (m, 2H), 7.28–
7.23 (m, 3H), 7.22–7.12 (m, 5H), 6.91 (m, 2H), 6.54 (m, 2H), (2 CH2
C6H5, CH2C6H4, 3 COC6H5); 5.85 (m, 1H, CH2CH@CH2); 5.76 (dd, 1H,
3.10. Allyl 2-O-acetyl-3,4-di-O-benzyl-
(1?2)-3,4-di-O-benzoyl-6-O-benzyl-
(1?3)-2-O-benzoyl-4-O-benzyl- -rhamnopyranoside (25)
a
-
L
-rhamnopyranosyl-
a
-D-galactopyranosyl-
a-L
3
3
J3 ,4 = 3.4 Hz, H-30); 5.68 (dd, 1H, J2,3 = 3.3 Hz, H-2); 5.59 (dd, 1H,
0
0
3
3
J4 ,5 = 1.0 Hz, H-40); 5.42 (d, 1H, J1 ,2 = 3.5 Hz, H-10); 5.31–5.16 (m,
Via thioglycoside 10: Glycosyl acceptor 24 (215 mg,
0.25 mmol), donor 10 (158 mg, 0.33 mmol), and molecular sieves
(4 Å, 1 g) were dried under high vacuum for 1 h at room tempera-
ture. The solids were then suspended in dry CH2Cl2 (26 mL), and
the reaction mixture was stirred for 30 min at room temperature
under an argon atmosphere in the dark. After cooling to ꢀ10 °C,
NIS (176 mg, 0.78 mmol) and AgOTf (68 mg, 0.26 mmol, dissolved
in 1 mL dry toluene) were added and the suspension was stirred
for 10 min at ꢀ10 °C and then 1 h at room temperature. After com-
plete reaction (monitored by TLC), the reaction mixture was neu-
tralized with NEt3 and filtered through Celite. The filtrate was
washed with cold aq 1 M Na2S2O3 (2 ꢂ 30 mL) and aq NaCl
(1 ꢂ 30 mL), dried, and concentrated. Purification by flash chroma-
tography (eluent gradient ethyl acetate in toluene 4?6%) gave
compound 25 (203 mg, 66%) as a colorless syrup.
0
0
0
0
2H, CH2CH@CH2); 5.02, 4.88 (2d, 2H, 2J = 10.7 Hz), 4.33, 4.27 (2d,
2H, 2J = 12.0 Hz), 4.22 (center of qAB, 2H, 2J = 12.3 Hz) (2 CH2C6H5,
3
CH2C6H4); 4.93 (d, 1H, J1,2 = 1.8 Hz, H-1); 4.52 (ddd, 1H,
3
3
J4 ,5 = 1.0 Hz, H-50); 4.45 (dd, 1H, J3,4 = 9.7 Hz, H-3); 4.07 (dd,
0
0
1H, J2 ,3 10.6 Hz, H-20); 4.15 (m, 1H), 4.01 (m, 1H), (CH2CH@CH2);
0
0
3
3
3.90 (dq, 1H, J4,5 = 9.7 Hz, J5,6 = 6.3 Hz, H-5); 3.74 (‘t’, 1H,
3
J4,5 = 9.7 Hz, H-4); 3.69 (s, 3H, OCH3); 3.46 (dd, 1H, 3J5 ,6b = 6.8 Hz,
0
0
3
2
H-6b0); 3.29 (dd, 1H, J5 ,6a = 5.5 Hz, J6a ,6b = 10.4 Hz, H-6a0); 1.46
0
0
0
0
(d, 3H, J5,6 = 6.2 Hz, H-6); 13C NMR (125.8 MHz, CDCl3): d 166.1,
3
165.4, 165.4 (3 COC6H5); 159.0 (p-CH2C6H4); 138.1, 137.9 (2 i-CH2
C6H5); 133.6 (CH2CH@CH2); 133.2, 133.1, 132.8 (3 p-COC6H5);
130.0, 129.7, 129.6, 129.6, 128.6, 128.4, 128.4, 128.3, 128.0, 127.5
(2) (2 o-, m-CH2C6H5, o-CH2C6H4, 3 o-, m-COC6H5); 129.9, 129.8,
129.7 (3 i-COC6H5); 128.0, 127.2 (2 p-CH2C6H5); 117.6 (CH2
CH@CH2); 113.5 (m-CH2C6H4); 96.7 (C-1); 92.6 (C-10); 79.7 (C-4);
72.3 (C-3); 71.9 (C-20); 76.1, 72.6, 71.6 (2 CH2C6H5, CH2C6H4);
70.4 (C-30); 69.9 (C-40); 68.2 (C-60); 68.2 (C-5); 68.1 (CH2CH@CH2);
Via 1-O-acetate 16: Glycosyl acceptor 24 (215 mg, 0.25 mmol),
donor 16 (141 mg, 0.33 mmol), and molecular sieves (4 Å, 1 g)
were dried under high vacuum for 1 h at room temperature. The

104
I. Nilsson et al. / Carbohydrate Research 404 (2015) 98–107
solids were then suspended in dry CH2Cl2 (9 mL), and the reaction
mixture was stirred for 1 h at room temperature under an argon
atmosphere in the dark. After the addition of trimethylsilyl trifluo-
reaction (monitored by TLC), the reaction mixture was neutralized
with Amberlite (H+) resin and filtered through Celite. The filtrate
was concentrated and the raw material was purified by flash chro-
romethanesulfonate (144
l
L, 0.8 mmol), the suspension was stir-
matography (solvent B3) to give compound 26 (50 mg, 74%) as a
23
red 36 h at room temperature. After complete reaction
(monitored by TLC), the reaction mixture was passed through a
layer of alkaline alumina by elution with chloroform. The filtrate
was washed with water (2 ꢂ 15 mL), dried, and concentrated. Puri-
fication by flash chromatography (eluent gradient ethyl acetate in
toluene 4?6%) gave compound 25 (188 mg, 61%) as a colorless
syrup.
Via glycosyl bromide 17: Glycosyl acceptor 24 (217 mg,
0.25 mmol), mercury(II) cyanide (39 mg, 0.15 mmol), mercury(II)
bromide (18 mg, 0.05 mmol), and molecular sieves (4 Å, 1 g) were
dried under high vacuum for 1 h at room temperature. A solution
of glycosyl donor 17 (157 mg, 0.35 mmol) in dry acetonitrile
(10 mL) was added to the glycosyl acceptor, mercury(II) cyanide,
mercury(II) bromide, and molecular sieves. The reaction mixture
was then stirred for 24 h under an argon atmosphere at room tem-
perature. After complete reaction (monitored by TLC), the reaction
mixture was passed through a layer of Celite by elution with chlo-
roform. The filtrate was washed with water (2 ꢂ 15 mL), 30% aq KI
solution (2 ꢂ 15 mL) and water (2 ꢂ 15 mL), dried and concen-
trated. Purification by flash chromatography (eluent gradient ethyl
colorless syrup: [
a]
ꢀ9.2 (c 0.5, CHCl3); Rf = 0.54 (EtOAc); 1H
D
NMR (500.13 MHz, CDCl3): d 7.36–7.20 (m, 20H, 4 CH2C6H5); 5.87
3
(m, 1H, CH2CH@CH2); 5.38 (d, 1H, J1 ,2 = 2.0 Hz, H-100); 5.29–
00 00
3
5.15 (m, 2H, CH2CH@CH2); 5.01 (d, 1H, J1 ,2 = 3.8 Hz, H-10); 4.84,
4.62 (2d, 2H, 2J = 11.4 Hz); 4.72, 4.59 (2d, 2H, 2J = 11.4 Hz), 4.68
(center of qAB, 2H, 2J = 11.4 Hz), 4.49, 4.35 (2d, 2H, 2J = 12.0 Hz),
0
0
3
(4 CH2C6H5); 4.79 (d, 1H, J1,2 = 1.2 Hz, H-1); 4.18 (br m, 1H, H-
3
200); 4.13 (m, 1H, CHHCH@CH2); 4.07 (dd, 1H, J2 ,3 = 9.8 Hz,
0
0
3
J1 ,2 = 3.8 Hz, H-20); 4.01–3.88 (m, 7H, H-2, H-3, H-30, H-300, H-40,
0
0
3
3
H-50, CHHCH@CH2); 3.78 (dq, 1H, J4,5 = 9.8 Hz, J5,6 = 6.3 Hz, H-
3
3
5); 3.70 (dq, 1H, J4 ,5 = 8.9 Hz, J5 ,6 = 6.3 Hz, H-500); 3.50–3.44
00 00
00 00
2
3
(m, 3H, H-4, H-400, H-6a0); 3.22 (dd, 1H, J = 10.7 Hz, J5 ,6b = 3.5 Hz,
0
0
H-6b0); 3.64 (d, 1H, 3JH,OH = 1.4 Hz, OH); 3.29 (d, 1H, 3JH,OH = 1.4 Hz,
OH); 2.60 (d, 1H, 3JH,OH = 9.0 Hz, OH); 2.56 (d, 1H, 3J2 ,OH-2 = 1.8 Hz,
00
00
3
3
OH-200); 1.35 (d, 3H, J5,6 = 6.3 Hz, H-6); 1.30 (d, 3H, J5 ,6 = 6.3 Hz,
H-600); 13C NMR (125.8 MHz, CDCl3): d 138.4, 138.2, 138.0, 137.1 (4
i-CH2C6H5); 133.8 (CH2CH@CH2); 128.5, 128.5, 128.4, 128.4, 127.8,
127.8, 127.8, 127.3 (4 o-, m-CH2C6H5); 128.0, 127.8, 127.7, 127.7 (4
p-CH2C6H5); 117.5 (CH2CH@CH2); 99.7 (C-100); 98.3 (C-1); 94.9 (C-
10); 79.9 (C-300); 79.6 (C-4); 79.4 (C-400); 76.1 (C-3); 75.2, 74.7, 73.9,
72.2 (4 CH2C6H5); 72.8 (C-20); 71.4 (C-40); 70.9 (C-30); 70.8 (C-60);
68.5 (C-500); 68.4 (C-200); 68.0 (C-50); 68.0 (CH2CH@CH2); 67.5 (C-
2); 67.4 (C-5); 18.0 (C-600); 18.0 (C-6). HRMS (ESI-TOF): calcd for
00 00
acetate in toluene 4?6%) gave compound 25 (110 mg, 35%) as a
24
colorless syrup: [
a]
D
+128.1 (c 1.0, CHCl3); Rf = 0.53 (solvent B2);
1H NMR (500.13 MHz, CDCl3): d 8.09 (m, 2H), 7.97 (m, 2H), 7.80
(m, 2H), 7.60 (m, 2H), 7.49–7.43 (m, 3H), 7.40–7.13 (m, 22H),
C
49H60O14 (M+Na+): m/z 895.3875, found: m/z 895.3891. Anal.
3
0
0
7.07 (m, 2H), (4 CH2C6H5, 3 COC6H5); 5.92 (dd, 1H, J3 ,4 = 3.5 Hz,
Calcd for C49H60O14 (872.99): C, 67.41; H, 6.93. Found: C, 67.77;
H, 6.94.
3
H-30); 5.82 (m, 1H, CH2CH@CH2); 5.61 (dd, 1H, J2,3 = 2.9 Hz,
3
3
J1,2 = 1.9 Hz, H-2); 5.57 (dd, 1H, J4 ,5 = 1.3 Hz, H-40); 5.40 (d, 1H,
0
0
3
J1 ,2 = 3.5 Hz, H-10); 5.27–5.12 (m, 2H, CH2CH@CH2); 5.09 (dd,
3.12. Propyl
a-L-rhamnopyranosyl-(1?2)-a-D-galactopyranosyl-
0
0
1H, 3J2 ,3 = 3.4 Hz, H-200); 5.05, 4.91 (2d, 2H, J = 10.4 Hz, CH2C6H5);
(1?3)- -rhamnopyranoside (27)
a-L
2
00 00
3
3
4.88 (d, 1H, J1 ,2 = 1.9 Hz, H-100); 4.87 (d, 1H, J1,2 = 1.9 Hz, H-1);
00 00
2
4.74, 4.57 (2d, 2H, J = 11.4 Hz, CH2C6H5); 4.68 (m, 1H, H-50); 4.49
To a solution of compound 26 (45 mg, 0.05 mmol) in methanol
(6 mL) 20% palladium(II) hydroxide on carbon (75 mg) was added.
The suspension was stirred for 43 h under a hydrogen atmosphere
at room temperature (monitored by TLC). The mixture was then fil-
tered over Celite by elution with methanol and the combined fil-
trates were concentrated. Purification by flash chromatography
3
3
(dd, 1H, J3,4 = 9.8 Hz, H-3); 4.46 (dd, 1H, J2 ,3 = 10.7 Hz, H-20);
4.22 (center of qAB, 2H, 2J = 12.0 Hz, CH2C6H5); 4.16, 3.44 (2d, 2H,
2J = 10.6 Hz) (CH2C6H5); 4.14–4.10 (m, 1H, CHHCH@CH2); 3.99–
0
0
3
3.92 (m, 2H, H-500, CHHCH@CH2); 3.90 (dq, 1H, J4,5 = 9.5 Hz,
3J5,6 = 6.2 Hz, H-5); 3.79 (‘t’, 1H, J4,5 = 9.5 Hz, H-4); 3.49 (dd, 1H,
3
3
3
2
J5 ,6a = 6.9 Hz, H-6a0); 3.28 (dd, 1H, J5 ,6b = 5.4 Hz, J6a ,6b = 10.4
(solvent C1) afforded compound 27 (25 mg, 94%) as a colorless
0
0
0
0
0
0
3
23
Hz, H-6b0); 3.27 (dd, 1H, J3 ,4 = 9.0 Hz, H-300); 3.21 (‘t’, 1H,
powder: [
a
]
ꢀ46.3 (c 1.0, H2O); Rf = 0.62 (solvent D1); 1H NMR
00 00
D
3
3
J4 ,5 = 9.0 Hz, H-400); 1.64 (s, 3H, COCH3); 1.48 (d, 3H,
(300.13 MHz, CD3OD): d 5.04 (d, 1H, J1 ,2 = 1.7 Hz, H-100); 5.01
00 00
00 00
3
3
3
3
J5,6 = 6.2 Hz, H-6); 1.38 (d, 3H, J5 ,6 = 6.2 Hz, H-600); 13C NMR
(d, 1H, J1 ,2 = 3.6 Hz, H-10); 4.71 (d, 1H, J1,2 = 1.7 Hz, H-1); 4.19
00 00
0
0
3
3
3
(ddd, 1H, J5 ,6a = 6.4 Hz, J5 ,6b = 5.8 Hz, J4 ,5 = 1.0 Hz, H-50);
4.05–3.90 (m, 5H, H-2, H-20, H-200, H-30, H-40); 3.78–3.68 (m, 4H,
H-3, H-300, H-60); 3.67–3.58 (m, 3H, H-5, H-500, CHHCH2CH3); 3.49
0
0
0
0
0
0
(125.8 MHz, CDCl3): d 168.8 (COCH3); 165.5, 165.5, 165.2 (3 COC6-
H5); 138.9, 138.3, 138.1, 137.8 (4 i-CH2C6H5); 133.6 (CH2CH@CH2);
133.2, 133.1, 132.9 (3 p-COC6H5); 130.5, 129.7, 129.7, 129.0, 128.6,
128.5, 128.3, 128.2, 128.2, 128.2, 128.2, 127.9, 127.7, 127.4 (4 o-,
m-CH2C6H5, 3 o-, m-COC6H5); 129.6, 129.5, 129.4 (3 i-COC6H5);
127.5, 127.3, 127.2 (3 p-CH2C6H5); 117.6 (CH2CH@CH2); 100.1 (C-
100); 96.5 (C-1); 94.6 (C-10); 80.0 (C-4); 79.9 (C-400); 77.9 (C-300);
72.4 (C-3); 72.1 (C-20); 76.1, 74.9, 72.7, 71.2 (4 CH2C6H5); 70.9
(C-30); 70.0 (C-40); 68.6, 68.5 (C-5, C-500); 68.5 (C-200); 68.4 (C-2);
68.3 (C-60); 68.2 (CH2CH@CH2); 67.2 (C-50); 20.3 (COCH3); 18.3
(C-6); 18.2 (C-600); one p-CH2C6H5 not given. HRMS (ESI-TOF): calcd
for C72H74O18 (M+Na+): m/z 1249.4767, found: m/z 1249.4792.
Anal. Calcd for C72H74O18 (1227.35): C, 70.46; H, 6.08. Found: C,
70.03; H, 6.55.
(‘t’, 1H, J3,4 = 3J4,5 = 9.4 Hz, H-4); 3.43–3.34 (m, 2H, H-400, CHHCH2
3
3
00 00
CH3); 1.60 (m, 2H, CH2CH2CH3); 1.30 (d, 3H, J5,6(5 ,6 ) = 6.2 Hz),
3
1.29 (d, 3H, J5,6(5 ,6 ) = 6.3 Hz), (H-6, H-600); 0.95 (t, 3H,
00 00
13
3J = 7.5 Hz, CH3); C NMR (75.5 MHz, CD3OD): d 103.6 (C-100);
101.2 (C-1); 98.0 (C-10); 79.1 (C-3); 76.3 (C-20); 73.9 (C-400); 72.5
(C-4); 72.3 (C-50); 72.2 (C-300); 72.0 (C-200); 71.6 (C-40); 70.7 (C-
30); 70.4 (2) (CH2CH2CH3, C-5 or C-500); 69.5, 69.5 (C-2, C-5 or C-
500); 62.7 (C-60); 23.8 (CH2CH2CH3); 18.2, 18.1 (C-6, C-600); 11.1
(CH3). HRMS (ESI-TOF): calcd for C21H38O14 (M+Na+): m/z
537.2154, found: m/z 537.2167. Anal. Calcd for
C21H38O14
(514.52): C, 49.02; H, 7.44. Found: C, 49.00; H, 7.48.
3.11. Allyl 3,4-di-O-benzyl-
benzyl- -galactopyranosyl-(1?3)-4-O-benzyl-
rhamnopyranoside (26)
a
-
L
-rhamnopyranosyl-(1?2)-6-O-
3.13. 2-O-Acetyl-3,4-di-O-benzyl-
3,4-di-O-benzoyl-6-O-benzyl- -galactopyranosyl-(1?3)-2-O-
benzoyl-4-O-benzyl- -rhamnopyranosyl (N-
a-L-rhamnopyranosyl-(1?2)-
a-
D
a-
L
-
a-D
a
-L
phenyl)trifluoroacetimidate (29)
Compound 25 (95 mg, 0.08 mmol) was dissolved in dry MeOH
(5 mL) and methanolic NaOMe (1 M, 1 mL) was added. The reaction
mixture was stirred for 20 h at room temperature. After complete
To a solution of compound 25 (245 mg, 0.2 mmol) in MeOH/
CH2Cl2 (6.5 mL, 1.6:1) palladium chloride (8 mg, 0.05 mmol) was

I. Nilsson et al. / Carbohydrate Research 404 (2015) 98–107
105
added at room temperature. The reaction mixture was stirred for
16 h at room temperature. After complete reaction (monitored by
TLC), the mixture was filtrated through Celite by elution with CH2
Cl2 and concentrated to yield the hemiacetal intermediate 28
(C-500); 68.4 (C-200); 67.8 (C-60); 67.3 (C-50); 66.7 (C-2); 20.3
(COCH3); 18.4 (C-6); 18.1 (C-600); CCF3 signal not given; 19F NMR
(282.4 MHz, CDCl3): d ꢀ75.7 (CF3). HRMS (ESI-TOF): calcd for C77
H74F3NO18 (M+Na+): m/z 1380.4750, found: m/z 1380.4751.
(
a
,b = 4:1.3) in a satisfying purity for the next step: Rf = 0.16 (sol-
vent B2);
-anomer 1H NMR (500.13 MHz, CDCl3): d 8.10 (m, 2H),
7.97 (m, 2H), 7.82 (m, 2H), 7.62–7.56 (m, 3H), 7.49–7.43 (m, 4H),
7.40–7.07 (m, 22H) (4 CH2C6H5, COC6H5); 5.90 (dd, 1H,
J2 ,3 = 10.6 Hz, J3 ,4 = 3.5 Hz, H-30); 5.55–5.51 (m, 2H, H-2, H-40);
a
3.14. Allyl 3,4-di-O-benzyl-
O-benzoyl-6-O-benzyl- -galactopyranosyl-(1?3)-2-O-
benzoyl-4-O-benzyl- -rhamnopyranoside (30)
a-L-rhamnopyranosyl-(1?2)-3,4-di-
a-D
3
a-L
3
3
0
0
0
0
3
3
5.41 (d, 1H, J1 ,2 = 3.5 Hz, H-10); 5.18 (d, 1H, J1,2 = 1.9 Hz, H-1);
Compound 25 (245 mg, 0.2 mmol) was added to a stirred meth-
anolic HCl solution [0.28 M, 10 mL, prepared by adding 0.2 mL
acetyl chloride to 10 mL ice-cold dry MeOH], and the mixture
was kept for 18 h under an argon atmosphere at room temperature
(monitored by TLC). The reaction mixture was then filtered
through a layer of alkaline alumina by elution with chloroform.
The combined filtrates were dried and concentrated. Purification
0
0
3
3
5.11 (dd, 1H, J2 ,3 = 3.5 Hz, J1 ,2 = 1.9 Hz, H-200); 5.07, 4.88 (2d,
00 00
00 00
2H, 2J = 10.5 Hz, CH2C6H5); 4.90 (d, 1H, J1 ,2 = 1.9 Hz, H-100);
3
00 00
2
4.76, 4.57 (2d, 2H, J = 11.4 Hz, CH2C6H5); 4.68 (m, 1H, H-50); 4.53
3
3
3
0
0
(dd, 1H, J3,4 = 9.8 Hz, J2,3 = 2.8 Hz, H-3); 4.49 (dd, 1H, J2 ,3 = 10.6
Hz, H-20); 4.23 (center of qAB, 2H, 2J = 12.0 Hz, CH2C6H5); 4.20–3.59
(2d, 2H, 2J = 10.9 Hz, CH2C6H5); 4.07 (dq, 1H, J4,5 = 9.5 Hz,
3
3
3
3
00 00
00 00
J5,6 = 6.2 Hz, H-5); 3.94 (dq, 1H, J4 ,5 = 9.5 Hz, J5 ,6 = 6.3 Hz,
by flash chromatography (solvent B4) gave compound 30
3
3
23
H-500); 3.77 (‘t’, 1H, J3,4 = 9.8 Hz, J4,5 = 9.5 Hz, H-4); 3.50 (dd, 1H,
(175 mg, 74%) as a colorless foam: [
a]
+146.1 (c 0.5, CHCl3);
D
2
3
3
J6a ,6b = 10.4 Hz, J5 ,6a = 6.9 Hz, H-6a0); 3.77 (dd, 1H, J3 ,4 = 8.9
Rf = 0.29 (solvent B2); 1H NMR (500.13 MHz, CDCl3): d 8.08 (m,
0
0
0
0
00 00
3
3
Hz, H-300); 3.32 (dd, 1H, J5 ,6b = 5.4 Hz, H-6b0); 3.23 (‘t’, J4 ,5 = 9.5 -
2H), 7.95 (m, 2H), 7.86 (m, 2H), 7.58 (m, 3H), 7.48 (m, 1H), 7.43
0
0
00 00
Hz, H-400); 2.85 (br s, 1H, OH); 1.67 (s, 3H, COCH3); 1.44 (d, 3H,
(m, 3H), 7.40–7.10 (m, 23H), (4 CH2C6H5, 3 COC6H5); 5.86 (dd,
3
3
3
J5,6 = 6.2 Hz, H-6); 1.37 (d, 3H, J5 ,6 = 6.3 Hz, H-600); 13C NMR
1H, J3 ,4 = 3.5 Hz, H-30); 5.83 (m, 1H, CH2CH@CH2); 5.66 (dd, 1H,
00 00
0
0
3
3
3
J3 ,4 = 3.5 Hz, J4 ,5 = 1.5 Hz, H-40); 5.58 (dd, 1H, J2,3 = 3.0 Hz,
0
0
0
0
(125.8 MHz, CDCl3): d 168.9 (COCH3); 165.5, 165.5, 165.2 (3 COC6-
H5); 138.8, 137.9, 137.8, 137.8 (4 i-CH2C6H5); 129.5, 129.5, 129.4 (3
i-COC6H5); 133.2, 133.1, 132.9 (3 p-COC6H5); 130.7–127.2 (several
signals of o-, m-COC6H5, o-, m-, p-CH2C6H5); 100.1 (C-100); 95.3 (C-
10); 92.1 (C-1); 80.0 (C-4); 79.8 (C-400); 77.7 (C-300); 72.5 (C-3); 72.4
(C-20); 76.0, 74.9, 72.7, 71.1 (4 CH2C6H5); 70.9 (C-30); 69.9 (C-40);
69.1 (C-2); 68.6 (C-5); 68.4 (C-500); 68.4 (C-200); 68.3 (C-60); 67.4
(C-50); 20.4 (COCH3); 18.3 (C-6); 18.1 (C-600). HRMS (ESI-TOF): calcd
for C69H70O18 (M+Na+): m/z 1209.4454, found: m/z 1209.4454.
To a solution of the hemiacetal 28 in acetone (10 mL) and water
3
3
J1,2 = 1.8 Hz, H-2); 5.37 (d, 1H, J1 ,2 = 2.8 Hz, H-10); 5.27–5.12
0
0
(m, 2H, CH2CH@CH2); 5.06, 4.88 (2d, 2H, 2J = 10.4 Hz, CH2C6H5);
3
3
4.98 (d, 1H, J1 ,2 = 1.5 Hz, H-100); 4.91 (d, 1H, J1,2 = 1.8 Hz, H-1);
00 00
2
4.71, 4.61 (2d, 2H, J = 11.0 Hz, CH2C6H5); 4.69 (m, 1H, H-50); 4.49
3
3
(dd, 1H, J3,4 = 10.0 Hz, J2,3 = 3.0 Hz, H-3); 4.49 (dd, 1H,
3
3
J2 ,3 = 10.0 Hz, J1 ,2 = 2.8 Hz, H-20); 4.22 (center of qAB
, 2H,
0
0
0
0
2J = 12.0 Hz), 4.07, 3.88 (2d, 2H, 2J = 10.7 Hz), (2 CH2C6H5); 4.11
(m, 1H), 4.97 (m, 1H), (CH2CH@CH2); 3.92–3.86 (m, 1H, H-5);
3
3
3.83 (dd, 1H, J4 ,5 = 9.1 Hz, H-500); 3.78 (‘t’, 1H, J3,4 = 10.0 Hz,
00 00
3
2
J4,5 = 9.5 Hz, H-4); 3.71 (br, 1H, H-200); 3.48 (dd, 1H, J6a ,6b = 10.4
0
0
(50
lL), Cs2CO3 (189 mg, 0.6 mmol) and (N-phenyl)trifluoroace-
3
Hz, J5 ,6a = 6.9 Hz, H-6a0); 3.32–3.28 (m, 2H, H-400, H-6b0); 3.25
0
0
timidoyl chloride (56
l
L, 0.4 mmol) were added at room tempera-
3
3
(dd, 1H, J3 ,4 = 8.8 Hz, J2 ,3 = 2.8 Hz, H-300); 2.22 (br s, 1H, OH);
00 00
00 00
ture. The reaction mixture was stirred for 3 h at room temperature.
After complete reaction (monitored by TLC), the mixture was fil-
tered through Celite by elution with chloroform. The combined fil-
trates were concentrated and purified by flash chromatography
3
3
1.45 (d, 3H, J5,6 = 6.2 Hz, H-6); 1.35 (d, 3H, J5 ,6 = 6.0 Hz, H-600);
13C NMR (125.8 MHz, CDCl3): d 165.5, 165.5, 165.5 (3 COC6H5);
138.7, 138.1, 138.0, 137.7 (4 i-CH2C6H5); 133.5 (CH2CH@CH2);
133.2, 133.1, 133.0 (3 p-COC6H5); 130.5, 129.7, 129.6, 128.6,
128.5, 128.4, 128.3 (2), 128.3, 128.2, 128.0, 128.0, 127.4, 127.3 (4
o-, m-CH2C6H5, 3 o-, m-COC6H5); 129.6, 129.5, 129.3 (3 i-COC6H5);
128.1, 127.6, 127.5, 127.2 (4 p-CH2C6H5); 117.6 (CH2CH@CH2);
101.4 (C-100); 96.3 (C-1); 95.2 (C-10); 80.1 (C-4); 79.8 (C-300); 79.7
(C-400); 76.1, 75.1, 72.7, 71.6 (4 CH2C6H5); 72.7, 72.5 (C-3, C-20);
71.0 (C-30); 69.9 (C-40); 68.9 (C-2); 68.5 (C-5); 68.3 (C-200); 68.3
(C-60); 68.2 (C-500); 68.2 (CH2CH@CH2); 67.4 (C-50); 18.2 (C-6);
17.9 (C-600). HRMS (ESI-TOF): calcd for C70H72O17 (M+Na+): m/z
1207.4662, found: m/z 1207.4666. Anal. Calcd for C70H72O17
(1185.31): C, 70.93; H, 6.12. Found: C, 71.16: H, 6.29.
00 00
(solvent D) to yield compound 29 (236 mg, 87%) as a colorless
23
foam: [
a
]
+164.2 (c 0.3, CHCl3); Rf = 0.57 (solvent B2); 1H NMR
D
(500.13 MHz, CDCl3): d 8.08 (m, 2H), 7.97 (m, 2H), 7.81 (m, 2H),
7.61–7.56 (m, 4H), 7.49–7.42 (m, 4H), 7.41–7.08 (m, 22H), 7.05
(m, 2H), 6.83 (m, 2H) (4 CH2C6H5, 3 COC6H5, NC6H5); 6.27 (br,
3
3
1H, H-1); 5.93 (dd, 1H, J2 ,3 = 10.7 Hz, J3 ,4 = 3.5 Hz, H-30); 5.78
0
0
0
0
3
3
3
0
0
(dd, 1H, J2,3 = 3.0 Hz, J1,2 = 2.0 Hz, H-2); 5.58 (dd, 1H, J3 ,4 = 3.5
3
3
Hz, J4 ,5 = 1.4 Hz, H-40); 5.46 (d, 1H, J1 ,2 = 3.3 Hz, H-10); 5.07
0
0
0
0
3
3
(dd, 1H, J2 ,3 = 3.3 Hz, J1 ,2 = 1.9 Hz, H-200); 5.08, 4.94 (2d, 2H,
00 00
00 00
2J = 10.4 Hz, CH2C6H5); 4.89 (d, 1H, J1 ,2 = 1.9 Hz, H-100); 4.74,
3
00 00
2
4.58 (2d, 2H, J = 11.4 Hz, CH2C6H5); 4.68 (m, 1H, H-50); 4.55 (dd,
3
3
3
0
0
1H, J3,4 = 9.8 Hz, J2,3 = 3.0 Hz, H-3); 4.50 (dd, 1H, J2 ,3 = 10.7 Hz,
H-20); 4.24 (center of qAB, 2H, 2J = 12.2 Hz), 4.15, 3.43 (2d, 2H,
2J = 10.7 Hz), (2 CH2C6H5); 4.03 (dq, 1H, 3J4,5 = 9.2 Hz,
3.15. Allyl 2-O-acetyl-3,4-di-O-benzyl-
(1?2)-3,4-di-O-benzoyl-6-O-benzyl-
(1?3)-2-O-benzoyl-4-O-benzyl- -rhamnopyranosyl-(1?2)-
3,4-di-O-benzyl- -rhamnopyranosyl-(1?2)-3,4-di-O-benzoyl-
6-O-benzyl- -galactopyranosyl-(1?3)-2-O-benzoyl-4-O-
benzyl- -rhamnopyranoside (31)
a-L
-rhamnopyranosyl-
-D-galactopyranosyl-
a
3
3
3
00 00
00 00
J5,6 = 6.1 Hz, H-5); 3.98 (dq, 1H, J4 ,5 = 9.1 Hz, J5 ,6 = 6.3 Hz, H-
a-L
3
3
500); 3.98 (‘t’, 1H, J3,4 = 9.8 Hz, J4,5 = 9.5 Hz, H-4); 3.43 (dd, 1H,
a-L
3
2
3
J5 ,6a = 6.3 Hz, H-6a0); 3.31 (dd, 1H, J6a ,6b = 10.2 Hz, J5 ,6b = 5.7
a-D
0
0
0
0
0
0
3
3
Hz, H-6b0); 3.26 (dd, 1H, J3 ,4 = 8.8 Hz, J2 ,3 = 3.3 Hz, H-300); 3.23
a-L
00 00
00 00
3
(‘t’, 1H, J4 ,5 = 9.1 Hz, H-400); 1.63 (s, 3H, COCH3); 1.54 (d, 3H,
00 00
J5,6 = 6.1 Hz, H-6); 1.39 (d, 3H, J5 ,6 = 6.3 Hz, H-600); 13C NMR
Glycosyl acceptor 30 (179 mg, 0.15 mmol), donor 29 (217 mg,
0.16 mmol), and molecular sieves (4 Å, 1 g) were dried under high
vacuum for 1 h at room temperature. The solids were then sus-
pended in dry CH2Cl2 (10 mL), and the reaction mixture was stirred
for 1 h under an argon atmosphere in the dark at room tempera-
ture. After cooling to ꢀ20 °C, trimethylsilyl trifluoromethanesulfo-
3
3
00 00
(125.8 MHz, CDCl3): d 168.8 (COCH3); 165.1, 165.2, 165.5 (3 COC6
H5); 143.2 (i-NC6H5); 137.4, 137.8, 138.2, 138.9 (4 i-CH2C6H5);
133.4, 133.3, 133.0 (3 p-COC6H5); 130.6–127.2 (several signals of
o-, m-COC6H5, o-, m-, p-CH2C6H5, m-NC6H5); 129.5, 129.3, 128.8
(3 i-COC6H5); 124.4 (p-NC6H5); 119.4 (o-NC6H5); 115.9 (q,
1JC,F = 287 Hz, CF3); 100.0 (C-100); 94.4 (C-10); 93.7 (br, C-1); 79.9
(C-400); 79.0 (C-4); 77.8 (C-300); 76.3, 75.0, 72.8, 71.2 (4 CH2C6H5);
71.7 (C-20); 71.5 (C-3); 71.3 (C-5); 70.8 (C-30); 69.8 (C-40); 68.5
nate (38 lL, 0.21 mmol) was added. The suspension was stirred for
10 min at that temperature and then 15 min at room temperature.
After complete reaction (monitored by TLC), the reaction mixture

106
I. Nilsson et al. / Carbohydrate Research 404 (2015) 98–107
24
was neutralized by the addition of NEt3 and filtered through Celite.
The filtrate was concentrated and purified by flash chromatogra-
phy (eluent gradient ethyl acetate in heptane 33?50%) to provide
syrup: [
a
]
+8.3 (c 0.5, CHCl3); Rf = 0.35 (solvent G); 1H NMR
D
(500.13 MHz, CDCl3): d 7.37–7.20 (m, 40H, 8 CH2C6H5); 5.88 (m,
3
00 00
1H, CH2CH@CH2); 5.34 (d, 1H, J1 ,2 = 2.4 Hz), 5.33 (d, 1H,
23
3
J1 ,2 = 2.2 Hz), (H-100A, H-100B); 5.30–5.17 (m, 2H, CH2CH@CH2);
00 00
compound 31 (187 mg, 53%) as a colorless syrup: [
a
]
+187.1 (c
D
3
3
1.0, CHCl3); Rf = 0.22 (solvent A1); 1H NMR (500.13 MHz, CDCl3):
d 8.02 (m, 4H), 7.94 (m, 4H), 7.84–7.77 (m, 4H), 7.60–7.54 (m,
6H), 7.48–6.95 (m, 51H), 6.75 (m, 1H), (8 CH2C6H5, 6 COC6H5);
5.11 (d, 1H, J1 ,2 = 3.8 Hz, H-10B); 5.09 (d, 1H, J1,2 = 1.6 Hz, H-
0
0
3
3
1B); 5.04 (d, 1H, J1 ,2 = 3.8 Hz, H-10A); 4.76 (d, 1H, J1,2 = 1.4 Hz,
H-1A); 4.85–4.57 (m, 12H), 4.50 (2d, 2H, 2J = 12.0 Hz), 4.37 (d,
1H, 2J = 12.0 Hz), 4.35 (d, 1H, 2J = 12.0 Hz), (8 CH2C6H5); 4.20–
4.12 (m, 4H, H-2, H-200A, H-200B, CHHCH@CH2); 4.08–4.00 (m, 5H,
H-2, H-20A, H-20B, H-3A, H-3B); 3.98–3.86 (m, 10H, H-30A, H-30B,
0
0
3
3
5.91 (dd, 1H, J2 ,3 = 10.7 Hz, J3 ,4 = 3.5 Hz, H-30B); 5.83 (m, 1H,
0
0
0
0
3
3
CH2CH@CH2); 5.82 (dd, 1H, J2 ,3 = 10.7 Hz, J3 ,4 = 3.5 Hz, H-30A);
0
0
0
0
3
3
5.68 (dd, 1H, J4 ,5 = 1.3 Hz, H-40A); 5.61 (dd, 1H, J4 ,5 = 1.3 Hz, H-
0
0
0
0
3
40B); 5.50–5.47 (m, 2H, H-2A, H-2B); 5.35 (d, 1H, J1 ,2 = 3.2 Hz,
H-300A, H-300B, H-40A, H-40B, H-5, H-50A, H-50B, CHHCH@CH2);
0
0
3
3
H-10A); 5.33 (d, 1H, J1 ,2 = 3.5 Hz, H-10B); 5.26–5.11 (m, 2H, CH2
3.82–3.76 (m, 3H, H-5A, H-500, OH); 3.71 (dq, 1H, J4 ,5 = 8.6 Hz,
0
0
00 00
CH@CH2); 5.06, 4.88 (2d, 2H, 2J = 10.5 Hz, CH2C6H5); 5.03 (‘t’, 1H,
J5 ,6 = 6.3 Hz, H-500); 3.56 (br s, 1H, OH); 3.57–3.44 (m, 6H, H-
3
00 00
3
3
00 00
00 00
J2 ,3 = 2.8 Hz,
J1 ,2 = 1.9 Hz, H-200B); 5.01, 4.79 (2d, 2H,
4A, H-4B, H-400A, H-400B, H-6a0A, H-6a0B); 3.31 (br s, 1H, OH);
3.30–3.25 (m, 3H, H-6b0A, H-6b0B, OH); 3.00 (br s, 1H, OH); 2.87
2J = 10.5 Hz, CH2C6H5); 4.97 (d, 1H, J1,2 = 1.3 Hz, H-100A); 4.95 (d,
3
3
3
3
1H, J1,2 = 1.6 Hz, H-1A); 4.84 (d, 1H, J1 ,2 = 1.9 Hz, H-100B); 4.72,
4.54 (2d, 2H, 2J = 11.4 Hz, CH2C6H5); 4.70, 4.49 (2d, 2H,
2J = 11.4 Hz, CH2C6H5); 4.70 (m, 1H, H-50A); 4.61 (m, 1H, H-50B);
(br s, 1H, OH); 2.78 (d, 1H, JH,OH = 8.0 Hz, OH); 1.38 (d, 3H,
J5,6(5 ,6 ) = 6.3 Hz), 1.36 (d, 3H, J5,6(5 ,6 ) = 6.3 Hz), 1.32 (d, 3H,
J5,6(5 ,6 ) = 6.2 Hz), 1.26 (d, 3H, J5,6(5 ,6 ) = 6.3 Hz), (H-6A, H-6B, H-
00 00
3
3
3
00 00
00 00
3
00 00
00 00
3
3
4.50 (dd, 1H, J3,4 = 9.5 Hz, J2,3 = 3.0 Hz, H-3A); 4.41 (dd, 1H,
600A, H-600B); 13C NMR (125.8 MHz, CDCl3): d 138.4, 138.3, 138.2,
138.1, 138.1, 137.9, 137.2, 137.1 (8 i-CH2C6H5); 133.8 (CH2
CH@CH2); 128.4 (2), 128.4, 128.3 (2), 128.3, 128.3, 128.2, 127.9,
127.8 (2), 127.8, 127.7, 127.7 (2), 127.5, 127.3, 127.2 (o-, m-CH2C6
H5); 127.9, 127.8, 127.7, 127.7, 127.6, 127.5, 127.4, 127.2 (p-CH2C6
H5); 117.4 (CH2CH@CH2); 101.3 (C-1B); 99.9 (C-100B); 99.5 (C-100A);
98.3 (C-1A); 94.7 (C-10A); 94.2 (C-10B); 79.8, 79.6, 79.5 (2), 79.1 (2)
(C-300A, C-300B, C-4A, C-4B, C-400A, C-400B); 76.1 (C-3A); 75.3, 75.2
(CH2C6H5); 75.1 (C-3B); 74.5 (2) (CH2C6H5); 73.9 (C-200A); 73.8
(C-20B); 73.7, 73.7 (2 CH2C6H5); 73.1 (C-20A); 72.3, 72.2 (CH2C6H5);
71.2, 71.2 (C-40); 70.7, 70.5 (CH2C6H5); 70.6 (C-30A, C-30B); 69.0 (C-
500A); 68.6 (C-500B); 68.4 (C-200B); 67.9 (2), 67.8 (C-5B, C-50A, C-50B);
67.9 (CH2CH@CH2); 67.4 (C-5A); 67.3, 67.0 (C-2A, C-2B); 18.0, 17.9,
17.8, 17.8 (C-6A, C-6B, C-600A, C-600B). HRMS (ESI-TOF): calcd for
3
3
3
J2 ,3 = 10.7 Hz, J1 ,2 = 3.2 Hz, H-20B); 4.37 (dd, 1H, J2 ,3 = 10.7 Hz,
0
0
0
0
0
0
3
3
3
J1 ,2 = 3.2 Hz, H-20A); 4.33 (dd, 1H, J3,4 = 9.8 Hz, J2,3 = 2.8 Hz, H-
0
0
3
00 00
3B); 4.27 (d, 1H, J1 ,2 = 1.6 Hz, H-1B); 4.22 (center of qAB, 2H,
2J = 12.0 Hz, CH2C6H5); 4.14–4.07 (m, 4H, CH2C6H5, CHHCH@CH2,
CHHC6H5); 4.03 (d, 1H, 2J = 11.7 Hz, CHHC6H5); 3.99–3.92 (m, 3H,
3
H-500B, CHHCH@CH2, CHHC6H5); 3.88 (dq, 1H, J4,5 = 9.5 Hz,
3J5,6 = 6.0 Hz, H-5A); 3.84–3.77 (m, 2H, H-4A, H-5B); 3.69 (dq, 1H,
3
3
3
J4 ,5 = 8.5 Hz, J5 ,6 = 6.3 Hz, H-500A); 3.61 (‘t’, 1H, J3,4 = 9.8 Hz,
00 00
00 00
3
3
3
00 00
00 00
J4,5 = 9.5 Hz, H-4B); 3.52 (‘t’, 1H, J2 ,3 = 2.8 Hz, J3 ,4 = 1.9 Hz, H-
2
3
200A); 3.48 (dd, 1H, J6a ,6b = 10.2 Hz, J5 ,6a = 6.9 Hz, H-6a0A);
0
0
0
0
3.37–3.25 (m, 6H, H-300A, H-400A, H-6a0B, H-6b0A, H-6b0B, CHHC6H5);
3.19–3.14 (m, 2H, H-300B, H-400B); 1.59 (s, 3H, COCH3); 1.43 (d, 3H,
J5,6 = 6.2 Hz, H-6A); 1.29 (d, 3H, 3J5 ,6 = 6.3 Hz, H-600B); 1.21 (d, 3H,
3
00 00
J5 ,6 = 6.3 Hz, H-600A); 0.97 (d, 3H, J5,6 = 6.2 Hz, H-6B); 13C NMR
C
95H114O27 (M+Na+): m/z 1710.7474, found: m/z 1710.7486. Anal.
3
3
00 00
(125.8 MHz, CDCl3): d 168.7 (COCH3); 165.5, 165.5, 165.5, 165.4,
165.2, 164.6 (6 COC6H5); 139.1, 139.1, 138.7, 138.3, 138.1, 137.8,
137.8, 137.7 (8 i-CH2C6H5); 133.7 (CH2CH@CH2); 133.1 (2), 133.0
(2), 132.9, 132.8 (6 p-COC6H5); 130.5, 130.4, 129.7 (2), 129.7,
129.6, 128.5–127.1 (signals of o-, m-COC6H5, o-, m-, p-CH2C6H5);
129.8, 129.7 (2), 129.6, 129.5, 129.2 (6 i-COC6H5); 117.5 (CH2
CH@CH2); 101.8 (C-100A); 100.0 (C-100B); 99.4 (C-1B); 96.1 (C-1A);
95.6 (C-10A); 93.6 (C-10B); 80.2 (C-400A); 80.1 (C-4A); 80.0 (C-
400B); 79.7 (C-4B); 79.1 (C-300A); 78.0 (C-200A); 77.8 (C-300B); 76.2,
76.0, 75.3, 74.9 (4 CH2C6H5); 74.3 (C-20A); 72.9 (C-3A); 72.8, 72.7
(2 CH2C6H5); 71.9 (C-20B); 71.7 (CH2C6H5); 71.5 (C-3B); 72.7 (2
CH2C6H5); 71.1 (C-30B); 70.4 (C-30A); 70.0 (C-40A); 69.8 (C-40B);
69.4 (C-2B); 68.9 (C-500A); 68.8 (C-5B); 68.5 (C-200B); 68.5 (C-5A);
68.4 (C-500B); 68.3 (C-60A); 68.3 (CH2CH@CH2); 67.6 (C-2A); 67.5
(C-60B); 67.5 (C-50A); 66.8 (C-50B); 20.3 (COCH3); 18.2, 18.1, 18.1,
17.8 (C-6A, C-6B, C-600A, C-600B). HRMS (ESI-TOF): calcd for
C139H140O34 (M+Na+): m/z 2376.9152, found: m/z 2376.9114. Anal.
Calcd for C139H140O34 (2354.58): C, 70.90; H, 5.99. Found: C, 71.16;
H, 6.21.
Calcd for C95H114O27 (1687.91): C, 67.60; H, 6.81. Found: C,
67.48; H, 6.97.
3.17. Propyl
a
-
L
-rhamnopyranosyl-(1?2)-
-rhamnopyranosyl-(1?2)- -rhamnopyranosyl-
-galactopyranosyl-(1?3)- -rhamnopyranoside (33)
a-D-galactopyranosyl-
(1?3)-
a
a
-L
a-L
a-L
(1?2)-
-D
To a solution of compound 32 (54 mg, 0.03 mmol) in methanol–
water (6 mL, 5:1) 20% palladium(II) hydroxide on carbon (84 mg)
was added. The suspension was stirred for 74 h under a hydrogen
atmosphere at room temperature (monitored by TLC). The mixture
was then filtered over Celite by elution with methanol. The com-
bined filtrates were concentrated and purified by flash chromatog-
raphy (solvent C1) to provide compound 33 (28 mg, 93%) as a
23
colorless powder: [
a]
D
ꢀ57.5 (c 0.5, H2O); Rf = 0.21 (solvent D1);
1H NMR (500.13 MHz, D2O): d 5.20 (d, 1H, J1 ,2 = 1.6 Hz, H-100B);
3
00 00
3
3
5.17 (d, 1H, J1 ,2 = 3.8 Hz, H-10B); 5.11 (d, 1H, J1 ,2 = 3.8 Hz, H-
0
0
0
0
3
3
10A); 5.02 (d, 1H, J1 ,2 = 1.7 Hz, H-100A); 5.00 (d, 1H, J1,2 = 1.9 Hz,
00 00
3
H-1B); 4.81 (d, 1H, J1,2 = 2.0 Hz, H-1A); 4.27 (dd, 1H,
3J2,3 = 3.2 Hz, J1,2 = 1.9 Hz, H-2B); 4.22–4.18 (m, 2H, H-50A, H-
3
3.16. Allyl 3,4-di-O-benzyl-
benzyl- -galactopyranosyl-(1?3)-4-O-benzyl-
rhamnopyranosyl-(1?2)-3,4-di-O-benzyl-
rhamnopyranosyl-(1?2)-6-O-benzyl- -galactopyranosyl-
(1?3)-4-O-benzyl- -rhamnopyranoside (32)
a-
L-rhamnopyranosyl-(1?2)-6-O-
50B); 4.10–4.05 (m, 5H, H-2A, H-200A, H-200B, H-30A, H-30B); 4.03
3
(m, 2H, H-40A, H-4B); 3.93, 3.93 (2dd, 2H, J2 ,3 = 10.3 Hz,
0
0
a-
D
a-L-
3
J1 ,2 = 3.8 Hz, H-20A, H-20B); 3.89–3.83 (m, 3H, H-3A, H-3B, H-
0
0
a-
L
-
3
3
300B); 3.79 (dd, 1H, J3 ,4 = 9.8 Hz, J2 ,3 = 3.5 Hz, H-300A); 3.77–
3.70 (m, 8H, H-5A, H-5B, H-500A, H-500B, H-6a0A, H-6b0A, H-6a0B,
H-6b0B); 3.64 (m, 1H), 3.49 (m, 1H), (CH2CH2CH3); 3.59, 3.57 (2‘t’,
00 00
00 00
a-D
a-L
3
3
2H, J3,4 = 3J4,5 = 9.8 Hz, H-4A, H-4B); 3.49, 3.46 (2‘t’, 2H, J3 ,4
=
00 00
To a solution of compound 31 (221 mg, 0.1 mmol) in dry MeOH
(10 mL) methanolic NaOMe (1 M, 1 mL) was added. The reaction
mixture was then stirred for 43 h at room temperature. After com-
plete reaction (monitored by TLC), the reaction mixture was neu-
tralized with Amberlite (H+) resin and filtered through Celite. The
filtrate was concentrated and purified by flash chromatography
(solvent B5) to give compound 32 (101 mg, 76%) as a colorless
3
J4 ,5 = 9.6 Hz, H-400A, H-400B); 1.60 (m, 2H, CH2CH2CH3); 1.30 (m,
12H, H-6A, H-6B, H-600A, H-600B); 0.91 (t, 3H, 3J = 7.5 Hz, CH2CH2-
00 00
13
CH3); C NMR (125.8 MHz, D2O): d = 103.0 (C-1B); 102.9 (C-100A);
101.2 (C-100B); 100.3 (C-1A); 95.6, 95.4 (C-10A, C-10B); 78.9 (C-
200A); 76.1, 75.5 (C-3A, C-3B); 75.6, 75.1 (C-20A, C-20B); 72.7, 72.6
(C-400A, C-400B); 71.6, 71.6 (C-50A, C-50B); 71.2, 71.2 (C-4A, C-4B);

I. Nilsson et al. / Carbohydrate Research 404 (2015) 98–107
107
70.9 (C-300A); 70.8 (C-200B); 70.7 (C-300B); 70.4, 70.2 (C-40A, C-40B);
70.5 (CH2CH2CH3); 70.3, 70.1, 70.0, 69.4 (C-5A, C-5B, C-500A, C-
500B); 70.1, 69.8 (C-30A, C-30B); 67.7 (C-2A); 67.4 (C-2B); 61.7,
61.6 (C-60A, C-60B); 22.8 (CH2CH2CH3); 17.6, 17.6, 17.5, 17.5 (C-
6A, C-6B, C-600A, C-600B); 10.7 (CH2CH2CH3). HRMS (ESI-TOF): calcd
for C39H68O27 (M+Na+): m/z 991.3840, found: m/z 991.3838. Anal.
Calcd for C39H68O27 (968.94): C, 48.34; H, 7.07. Found: C, 48.53;
H, 7.21.
8. Zuurmond, H. M.; Van der Laan, S. C.; Van der Marel, G. A.; Van Boom, J. H.
Carbohydr. Res. 1991, 215, c1–c3.
9. Zegelaar-Jaarsveld, K.; van der Marel, G. A.; van Boom, J. H. Tetrahedron 1992,
48, 10133–10148.
10. Lau, R.; Schule, G.; Schwaneberg, U.; Ziegler, T. Liebigs Ann. 1995, 1745–1754.
11. Pinto, B. M.; Morissette, D. G. J. Chem. Soc., Perkin Trans. 1 1987, 9–14.
12. Farouk, M.; Michalik, D.; Villinger, A.; Vogel, C. ARKIVOC 2013, 389–407.
13. Fürstner, A.; Müller, T. J. Am. Chem. Soc. 1999, 121, 7814–7821.
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