Synthesis of three regioisomers of the pentasaccharide part of the Skp1 glycoprotein of Dictyostelium discoideum

Article abstract of DOI:10.1016/j.tetasy.2009.02.040

Three regioisomers of the linear pentasaccharide part of the Skp1 glycoprotein, found in Dictyostelium discoideum, were prepared in the form of (2-trimethylsilyl)ethyl glycosides by means of 2+3 block syntheses using the disaccharide donor at the non-redu

Full text of DOI:10.1016/j.tetasy.2009.02.040

Tetrahedron: Asymmetry 20 (2009) 808–820
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Tetrahedron: Asymmetry
journal homepage: www.elsevier.com/locate/tetasy
Synthesis of three regioisomers of the pentasaccharide part of the Skp1
glycoprotein of Dictyostelium discoideum
Zoltán B. Szabó a, Mihály Herczeg a, Anikó Fekete a, Gyula Batta b, Anikó Borbás a,
a,c
András Lipták a,b, , Sándor Antus
*
a Research Group for Carbohydrates of the Hungarian Academy of Sciences, University of Debrecen, PO Box 94, H-4010, Hungary
b Department of Biochemistry, University of Debrecen, PO Box 55, H-4010, Hungary
c Department of Organic Chemistry, University of Debrecen, PO Box 20, H-4010, Hungary
a r t i c l e i n f o
a b s t r a c t
Article history:
Three regioisomers of the linear pentasaccharide part of the Skp1 glycoprotein, found in Dictyostelium dis-
coideum, were prepared in the form of (2-trimethylsilyl)ethyl glycosides by means of 2+3 block syntheses
using the disaccharide donor at the non-reducing end, and three different trisaccharide acceptors at the
Received 2 February 2009
Accepted 12 February 2009
Available online 1 April 2009
reducing end. Fucosylation of (2-trimethylsilyl)ethyl 3,4,6-tri-O-benzyl-b-D-galactopyranosyl-(1?3)-4,6-
O-benzylidene-2-deoxy-2-NPhth-b- -glucopyranoside with different fucosyl donors carrying an O-(2-
naphthyl)methyl ether as a temporary-protecting group at positions C2, C3 or C4 gave rise to the pro-
tected core trisaccharides. After selective removal of the (2-naphthyl)methyl group, the resulting accep-
D
This paper is dedicated to Professor George
Fleet, on the occasion of his 65th birthday
tors were glycosylated with the
a(1?6) linked digalactosyl donor to yield the respective three
regioisomeric pentasaccharides. Transformation of the phthalimido moiety into an N-acetyl group, fol-
lowed by catalytic hydrogenation of the reducible-protecting groups furnished the free target pentasac-
charides, which should be able to assist during the elucidation of the exact structure of the natural
pentasaccharide.
Ó 2009 Elsevier Ltd. All rights reserved.
1. Introduction
the Galpa(1?6)Galpa(1??) (E + D) disaccharide at the [Fuca
(1?2)Galpb(1?3)GlcNAc] (C + B + A) core-trisaccharide could not
be determined by the authors.1–4 It is also supposed that the glyco-
sylation of the core is carried out in the cytoplasm and not in the
nucleus of the cell. To investigate the biology of the glycosylation
process of the core region, the structure of the pentasaccharide must
be determined as the first step.
Skp1 protein, a part of an enzyme complex SCF, named as an
acronym of the participating proteins,1 is expressed ubiquitously
in eukaryotes to facilitate the selection of other proteins for spe-
cific posttranslational modifications. Skp1, found in the soil-living
amoeba Dictyostelium discoideum, is located in the cytoplasm and
involved in the ubiquitination of certain cell cycle and nutritional
regulatory processes. It was found that the 143th amino acid
(hydroxyproline, HyPro) of Skp1 is glycosylated with a galactose-
and a fucose-containing oligosaccharide, which is unusual for a
cytoplasmic protein. This glycan side-chain on a cytoplasmic/nu-
clear protein suggested a novel glycosylation pathway in the cyto-
plasm; supposedly the oligosaccharide was formed via complex
glycosylation. The analysis of the saccharide chain revealed that
it is a linear pentasaccharide; West et al. proposed the following
2. Results and discussion
We proposed that the required structural elucidation could be
solved in a synthetic manner, thus we planned to prepare the three
possible regioisomeric pentasaccharides in the form of glycosides
(compounds 1, 2 and 3, Scheme 1). Meanwhile, West et al.
reported5 the determination of the linkage between the digalacto-
syl cap structure and the core trisaccharide. In their experiments,
model compounds acting as substrates were used and enzymatic
structure:1 Galp
NAc(1??)HyPro (Fig. 1). The trisaccharide part (core) at the reduc-
ing end [Fuc (1?2)Galpb(1?3)GlcpNAc(1?] has been known as
the blood group type H antigen, but the Galp (1?6)Galp (1?
a(1?6)Galpa(1??)Fuca(1?2)Galpb(1?3)Glcp-
synthesis showed that a galactose unit is placed on the 1-OBn-a-
a
L-Fucp moiety. Co-chromatography with model compounds proved
a
a
that galactose was attached to the 3-position of L-fucose. We
thought that a more precise way to determine the exact linkage
cap structure has not been found elsewhere. The exact linkage of
* Corresponding author. Tel.: +36 52512900/22256; fax: +36 52512900/22342.
E-mail address: liptaka@puma.unideb.hu (A. Lipták).
The monossacharide constituents of the isomeric pentasaccharides are denoted
with capital letters starting with ’A’ from the reducing end.
0957-4166/$ - see front matter Ó 2009 Elsevier Ltd. All rights reserved.
doi:10.1016/j.tetasy.2009.02.040

Z. B. Szabó et al. / Tetrahedron: Asymmetry 20 (2009) 808–820
809
acceptor (C1+B+A, C2+B+A or C3+B+A) bearing one free OH-group
at a fixed position. The B + A and the E + D building blocks were
designed to be built up from monosaccharide fragments with the
appropriate-protecting groups, which allow the formation of the
interglycosidic bonds with the correct stereochemistry, and subse-
quent transformations. The protected B + A and E + D disaccharide
fragments should be converted into an acceptor and a donor,
respectively. We have published6 the preparation of the fucose
building blocks (C1, C2 and C3), carrying one temporary-protecting
group at the suitable position and the other two hydroxyls blocked
with permanent-protecting groups. Although examples of the syn-
OH
O
OH
HO
HO
O
O
A
B
HyPro(143)
HO
O
NHAc
H3C
O
C
OH
OH
HO
HO
HO
D
thesis of the Galpa a(1?2)Galpb
(1?6)Galp7,8 and the Fucp
O
HO
(1?3)GlcNAc9–12 oligosaccharide moieties have already been
reported, the protecting groups employed in these works were
not suitable for our purposes.
Herein, the total synthesis of the regioisomeric pentasaccha-
rides from monosaccharide building blocks is discussed in
detail.
O
HO
O
HO
E
OH
HO
Figure 1. Structure of the pentasaccharide part of the Skp1 glycoprotein.
2.1. Synthesis of the B+A disaccharide moiety
of galactose on fucose is the synthesis of the possible isomeric
pentasaccharides, thus we continued our experiments on the con-
struction of the isomeric structures.
The preparation of the pentasaccharides was based on (2-tri-
methylsilyl)ethyl (SE) glycosides and we planned to perform with
a 2+3 block synthesis (Scheme 1), that is, attaching the digalactosyl
residue (E + D) to the appropriate reducing-end trisaccharide
The fully protected bromosugar 413 with a 2-O-acetyl-partici-
pating group was reacted with the N-phthalimidoglucosamine
acceptor 514 in the presence of AgOTf to give 6, a compound with
a b(1?3) interglycosidic linkage (Scheme 2). Cleavage of the 2-O-
acetyl group of 6 with the Zemplén method did not result in the
formation of acceptor 7 directly, since under the conditions of
Ph
R2
NAP Bn
Bn NAP Bn
Bn Bn NAP
R3
Bn
R1
O
OBn
BnO
SPh
OR1
O
H3C
R3O
O
C
O
O
C1
C2
C3
+
A
O
OSE
B
OR2
BnO
OH
BA acceptor
NPhth
C donors
glycosylation,
selective removal of NAP
SE = -CH2CH2Si(CH3)3
Ph
O
OBn
BnO
BnO
O
O
O
O
A
OSE
B
O
R1
OBn
O
BnO
R2
Bn
H
R3
NPhth
Bn
Bn
H
C1
C2
C3
H
Bn
E
OR1
O
BnO
H3C C
BnO
+
OR2
O
R3O
Bn
Bn
AcO
CBA acceptors
O
glycosylation,
NHAc formation,
deprotection
SPh
D
AcO
ED donor
ONAP
OH
O
OH
OH
HO
OH
O
OH
HO
OH
HO
O
HO
HO
O
O
O
O
HO
A
O
A
OSE
B
A
OSE
O
B
HO
OSE
HO
B
HO
H3C
O
NHAc
O
NHAc
O
NHAc
O
H3C
C
O
C
H3C
O
C
O
OH
OH
OH
O
OH
HO
HO
OH
O
HO
OH
OH
HO
O
D
O
HO
HO
D
D
O
O
HO
HO
OH
O
O
HO
OH
HO
HO
O
E
O
HO
E
HO
HO
E
HO
O
HO OH
OH
3
1
2
Scheme 1. Synthetic pathway for the target pentasaccharides 1–3.

810
Z. B. Szabó et al. / Tetrahedron: Asymmetry 20 (2009) 808–820
OBn
O
Ph
OBn
O
BnO
BnO
O
O
Ph
BnO
O
O
O
a
O
OSE
NPhth
A
+
HO
O
OSE
NPhth
6 R= Ac (72 %)
B
BnO
AcO
OR
Br
4
5
b
7
R= H (56 %)
Scheme 2. Reagents and conditions: (a) AgOTf, sym-collidine, DCM, toluene, ꢀ74 °C?+25 °C, overnight; (b) (i) NaOMe, MeOH–DCM, rt, 72 h; (ii) TFAA, pyridine, 30 min; (iii)
cat. NaOMe, MeOH–DCM, rt, 2.5 h.
Table 1
Selected 1H and 13C NMR data of compounds 6 and 7
1
Compound Monosaccharide
unit
1H NMR—d (ppm) 3J (Hz), 13C NMR—d (ppm) JC1,H1 (Hz)
1
2
3
4
5
6a,b
6
GlcNPhth (A)
Galp (B)
5.12 (d, J1,2 = 10.0) 4.36–4.26 (m)a 4.67 (dd, JA = 10.2, JB = 8.8) 3.84–3.77 (m)a 81.17b 3.30–3.22 (m)a
a: 3.30–3.22 (m)a b:
3.61–3.55 (m)a 68.03
a: 4.36–4.26 (m)a b:
3.84–3.77 (m)a 68.68
98.17 (J = 163.6)
55.61
75.28
80.37
3.84–3.77 (m)a 72.05b 3.61–3.55 (m)a
66.35
5.13 (t, J = 8.5) 3.30–3.22 (m)a 70.81
0
0
4.44 (d, J1 ,2 = 8.0)
100.63 (J = 160.7)
71.64
7
GlcNPhth (A)
Galp (B)
5.34 (d, J1,2 = 8.5)
98.34 (J = 164.5)
4.29–4.24 (m)a
4.29–4.24 (m)a 4.81 (t, J = 9.5) 72.07
3.83 (t, J = 10.3) 73.46 3.27–3.18 (m)a 81.50b a: 2.87 (t, J = 9.0) b:
55.99
2.37 (m) 66.58
a
3.97–3.88 (m)a 3.27–3.18 (m) 73.04b
3.79–3.74 (m)a
81.00
3.69 (m) 65.77
a: 4.40 (m) b:
102.70 (J = 162.5)
68.90
3.79–3.74 (m)a 68.78
a
Overlap.
Interchangeable assignments.
b
Ph
O
O
BnO
O
O
OBn
O
A
b
OSE
SPh
ONAP
H3C
O
C
a
NPhth
B
BnO
7
+
OBn
BnO
O
8
H3C
O
C
9 (60%)
10
OH
(75%)
OBn
BnO
Ph
OBn
O
O
BnO
O
O
A
OSE
NPhth
O
B
BnO
SPh
OBn
H3C
BnO
O
C
a
O
7
+
ONAP
H3C
O
C
12
(68%)
13 (73%)
OBn
b
11
OH
BnO
Ph
O
O
BnO
O
O
OBn
O
A
OSE
SPh
OBn
a
NPhth
H3C
O
B
C
BnO
+
7
O
OBn
NAPO
H3C
O
C
14
OBn
15 (62%)
16 (75%)
b
OBn
HO
Scheme 3. Reagents and conditions: (a) NIS/TMSOTf, CH2Cl2, ꢀ50 °C, 30 min; (b) DDQ, CH2Cl2–H2O 9:1, rt, 25 min.

Z. B. Szabó et al. / Tetrahedron: Asymmetry 20 (2009) 808–820
811
the deacetylation opening of the phthalimido group also occurred.
acceptor 7 in the presence of NIS/TMSOTf promoter to yield 9, 12
or 15, respectively. The fucosylation reactions were carried out
under the same conditions and the desired compounds with an
Reclosure of the phthalimido ring and removal of the formed 20-O-
trifluoroacetyl group required two additional steps, following the
11
procedure described by Oscarson et al.
to afford compound 7
a-fucosidic linkage were obtained in each case (Scheme 3). The
in 56% overall yield. Our efforts to avoid the cumbersome prepara-
tion of the B + A disaccharide acceptor by using the more readily
removable chloroacetyl group at the 2-position of the Gal moiety
were unsuccessful. Glycosylation of 5 with different chloroacety-
lated donors did not give the desired compounds. These results will
be published elsewhere soon.
Surprisingly, the NMR spectra of compounds 6 and 7 differed to
a great extent, supposedly due to an intramolecular hydrogen bond
formed between the 20-OH and the phthaloyl-C@O after cleavage of
the 20-O-acyl group. The interaction fixed 7 in a definite conforma-
tion proved by the shift of the signals of both carbohydrate moie-
ties and the splitting of the phthaloyl-C@O (13C NMR) in compound
7 as compared to 6. The NMR-data of compounds 6 and 7 are
presented in Table 1.
next step was the selective cleavage of the 2-O-naphthylmethyl
ether from the trisaccharides to unblock the OH group at suitable
positions. Deprotection of the NAP-ether in the presence of benzyl
ethers and the other protecting groups could be achieved with
DDQ, and compounds 10, 13 and 16 were obtained in good yields.
The appropriate positions of the free OH-groups on the trisaccha-
rides were confirmed by NMR and the data are presented in Table
2. The
to the
a
- and b-shifts of the carbon atoms and the protons attached
L-fucose skeleton of the derivatives were characterized. In
the case of compounds 10 and 13, hydrogen bonding between
the free hydroxyl and the phthaloyl-C@O could again be observed,
3
as confirmed by the JH,OH coupling constants of the OH0s.
2.3. Synthesis of the E+D disaccharide building block
2.2. Preparation of the Cx+B+A trisaccharides
Development of the desired a(1?6) linkage between the E and
D units was planned by the coupling of a tetra-O-benzyl-galacto-
pyranosyl donor and an acceptor with a single OH group at the
The protected core trisaccharide was synthesized by coupling
the appropriate fucoside donor 8, 11 or 146 and disaccharide
Table 2
Selected 1H and 13C NMR data of compounds 9, 10, 12, 13, 15 and 16
1
Compound Monosaccharide
unit
1H NMR—d (ppm) 3J (Hz), 13C NMR—d (ppm) JC1,H1 (Hz)
1
2
3
4
5
6
Misc. signal
9(2-ONAP)
D
-GlcNPhth (A)
-Galp (B)
5.13 (d, J1,2 = 8.5)
98.38 (J = 164.0)
4.50–4.46 (m)a
100.38 (J = 159.0)
5.39 (d, J1,2 = 3.5)
97.37 (J = 170.5)
4.42–4.27 (m)a
56.43
5.04 (t, J = 9.5)
72.53
3.83–3.72
(m)a 78.21
3.91–3.83
(m)a 72.16
4.42–4.27
(m)a 80.31
3.69–3.55
a: 4.42–4.27 (m)a,b b:
PhCH: 5.55 (s)
100.64 (J = 162.5)
(m)a 66.48a 3.83–3.72 (m)a,b 68.52a
D
4.12 (dd, J1,2 = 7.6; 3.50 (dd, J2,3 = 9.6;
3.38 (m)
72.78
a,b: 3.69–3.55 (m)a
J2,3 = 9.5) 75.46a
3.69–3.55 (m)a
75.46a
J3,4 = 2.8) 83.15
3.83–3.72 (m)a
79.01
68.52a
L
-Fucp (C)
4.42–4.27
1.26 (d, J5,6 = 6.4) 16.49
(m)a 66.48a
10(2-OH)
D
-GlcNPhth (A)
-Galp (B)
5.29 (d, J1,2 = 8.6)
98.12 (J = 166.0)
4.46–4.40 (m)a
100.72 (J = 161.0)
4.81–4.73 (m)a
99.91 (J = 170.0)
4.36–4.28 (m)a
56.01
4.81–4.73 (m)a
74.00
3.91–3.75
(m)a 80.76
3.91–3.75
(m)a 71.69
3.54 (br s)
77.75
3.63–3.56
(m)a 66.26
3.27 (m)
72.64
3.99 (m)
67.37
a: 4.36–4.28 (m)a,b b:
3.91–3.75 (m)a,b 68.69
a: 3.63–3.56 (m)a,b b:
3.50–3.43 (m)a,b 68.53
1.21 (d, J5,6 = 6.4) 16.63
PhCH: 5.49 (s)
100.94 (J = 160.0)
D
3.91–3.75 (m)a
77.34
3.42–3.31 (m)a
82.45
L
-Fucp (C)
3.42–3.31 (m)a
69.46
3.42–3.31 (m)a
80.30
OH: 2.44 (d,
JOH,H = 8.6)
12(3-ONAP)
D
-GlcNPhth (A)
-Galp (B)
5.15 (d, J1,2 = 8.5)
98.43 (J = 163.0)
4.49–4.36 (m)a
100.54 (J = 161.0)
5.31 (d, J1,2 = 3.2)
97.45 (J = 172.0)
4.36–4.23 (m)a
56.43
4.99 (t, J = 9.5)
72.84
3.84–3.71
(m)a 78.45
3.84–3.71
(m)a 72.48
4.49–4.36
(m)a 80.41
3.62–3.52
a: 4.36–4.23 (m)a,ba,b b:
PhCH: 5.55 (s)
100.74 (J = 163.0)
(m)a 66.54a 3.84–3.71 (m)a,b 68.63
D
4.06 (t, J = 8.4)
75.81
3.48–3.41 (m)a
83.11
3.34 (m)
72.88
a: 3.64 (t, J = 8.3)b b:
3.62–3.52 (m)a,b 68.68
1.25 (d, 6.4) 16.56
L
-Fucp (C)
3.62–3.52 (m)a
75.90
3.84–3.71 (m)a
79.07
4.36–4.23
(m)a 66.54a
13(3-OH)
D
-GlcNPhth (A)
-Galp (B)
5.13 (d, J1,2 = 8.5)
98.53 (J = 164.0)
4.46–4.39 (m)a
100.39 (J = 160.0)
5.29 (d, J1,2 = 3.3)
96.77 (J = 171.0)
4.37–4.27 (m)a
56.25
4.97 (t, J = 9.5)
3.77–3.71
(m)a 80.11
3.91–3.84
(m)a 72.14
3.67–3.51
(m)a 80.15
3.67–3.51
(m)a 66.60
3.41–3.36
(m)a 72.80
4.19 (m)
66.43
a: 4.37–4.27 (m)a,b b:
3.79 (t, J = 10.2)b 68.60
a,b: 3.67–3.51 (m)a
68.50
PhCH: 5.53 (s)
100.75 (J = 161.0)
72.86
D
4.02 (dd, J1,2 = 7.5; 3.41–3.36 (m)a
J2,3 = 9.3) 75.61
83.17
L
-Fucp (C)
3.24 (dd, J1,2 = 3.3, 3.77–3.71 (m)a
1.25 (d, J5,6 = 6.5) 16.46
OH: 1.92 (d,
JOH,H = 4.6)
J2,3 = 10.2) 76.28
69.73
15(4-ONAP)
D
-GlcNPhth (A)
-Galp (B)
5.14 (d, J1,2 = 8.5)
98.41 (J = 164.0)
4.47 (d, J ffi 7.6)a
100.45 (J = 161.0)
4.36–4.25 (m)a
56.44
5.01 (t)a 72.77
3.81–3.73
(m)a 78.36
3.89–3.82
(m)a 72.46
3.61–3.53
(m)a 66.52
3.35 (t,
a: 4.36–4.25 (m)a,b b:
3.81–3.73 (m)a,b 68.60
a: 3.65 (t, J = 8.4)b b:
3.61–3.53 (m)a,b 68.67
PhCH: 5.54 (s)
100.73 (J = 161.0)
D
4.07 (dd)a 75.66
3.47–3.41 (m)a
83.13
J = 6.5)
72.87
L
-Fucp (C)
5.33 (d, J1,2 = 3.5)
97.50 (J = 172.0)
3.61–3.53 (m)a
75.84
3.81–3.73 (m)a
79.25
3.81–3.73
(m)a 80.38
4.36–4.25
1.27 (d, J5,6 = 6.5) 16.62
(m)a 66.56
16(4-OH)
D
-GlcNPhth (A)
-Galp (B)
5.17 (d, J1,2 = 8.5)
98.40 (J = 164.0)
4.43 (d, J1,2 = 7.5)
100.37 (J = 161.0)
5.31 (d, J1,2 = 3.6)
97.28 (J = 171.0)
4.41–4.25 (m)a
56.44
4.08 (dd, J1,2 = 7.5, 3.42 (dd, J2,3 = 9.5,
J2,3 = 9.5) 75.85
3.39–3.33 (m)a
75.03
5.01 (t, J = 9.5)
72.57
3.82–3.72
(m)a 77.80
3.83 (m)a
72.35
3.60 (m)
66.49
3.39–3.33
(m)a 72.89
4.41–4.25
(m)a 65.36
a: 4.41–4.25 (m)a,b b:
3.82–3.72 (m)a,b 68.57
a: 3.66 (m)a,b b: 3.55
(m)b 68.52
PhCH: 5.54 (s)
100.69 (J = 161.0)
D
J3,4 = 2.6) 82.93
L
-Fucp (C)
3.70 (dd, J2,3 = 10.1, 3.94 (br s)
1.31 (d, J5,6 = 6.6) 16.02
OH: 2.07 (s)
J3,4 = 3.1)a 80.21
69.82
a
Overlap.
Interchangeable assignments.
b

812
Z. B. Szabó et al. / Tetrahedron: Asymmetry 20 (2009) 808–820
OMIP
O
OMIP
O
O
OH
O
O
b
a
O
SPh
SPh
SPh
O
O
O
ONAP
OH
ONAP
19
17
18 (94%)
(84%)
MeO
MIP =
BnO
OBn
O
E
BnO
BnO
BnO
OBn
OH
O
O
NH
c
BnO
O
O
+
O
SPh
O
CCl3
O
O
SPh
D
ONAP
BnO
O
ONAP
20
19
21 (88 %)
21 (68 %)
OBn
BnO
BnO
OBn
O
BnO
BnO
+ 19
d
O
SPh
e
BnO
BnO
Br
22
23
Scheme 4. Reagents and conditions: (a) NAPBr, NaH, DMF, 0 °C?rt, 3 h; (b) CH3COOH(aq), CH2Cl2, 55 °C, 2.5 h; (c) TMSOTf, Et2O, ꢀ30 °C, 45 min; (d) Br2, CH2Cl2, 0 °C, 10 min;
(e) Bu4NBr, DCM–DMF, 0 °C, 24 h.
6-position. The D unit also needs a non-participating group at the
2-position for the synthesis of the planned pentasaccharides, and
to fulfill this requirement the 2-naphthylmethyl-protecting group
was selected.
to furnish a separable mixture of the anomers. In a subsequent
chromatographic step, donor 24 (E + D) was obtained in an accept-
able yield (Scheme 5). The NMR data for compound 24 are
presented in Table 3.
Compound 1715 was the starting material for the synthesis of
the partially protected D unit; first the 2-OH group was reacted
with (2-bromomethyl)naphthalene to furnish 18. Selective cleav-
age of the mixed (methoxydimethyl)methyl (MIP) acetal from
the primary position in a mild acidic medium resulted in the for-
mation of acceptor 19 from 17 in good overall yield (Scheme 4).
Galactosylation of 19 was attempted with 20,16 but the NMR spec-
tra of the chromatographically homogeneous material showed that
a mixture of both disaccharide stereoisomers was produced. Hop-
2.4. Synthesis of the pentasaccharides and removal of their
protecting groups
The E + D donor 24 and the appropriate trisaccharide acceptors
10, 13 and 16 were reacted and the planned three isomeric penta-
saccharides 25, 26 and 27 were obtained in acceptable yields. The
reactions were promoted by NIS/AgOTf and products with
glycosidic linkages were isolated in each case (Scheme 6).
a-inter-
ing to obtain a pure
a
-linked product, glycosylation of 19 was
For deblocking, first the transformation of the phthalimido
moiety into an N-acetyl and then removal of the reducible
groups by catalytic hydrogenation were planned. Treatment of
repeated with bromosugar 23, derived from 22.17 The reaction
under in situ anomerization conditions, introduced by Lemieux
for cis-glycoside synthesis, gave, again a mixture of the anomers.
The desired a-anomer could be isolated in pure form only after
protecting group manipulation; the 3,4-O-isopropylidene group of
21 was hydrolyzed and the crude product was directly acetylated
Table 3
Selected 1H and 13C NMR data of compound 24
1
Compound Monosaccharide 1H NMR—d (ppm) 3J (Hz), 13C NMR—d (ppm) JC1,H1
unit
(Hz)
OBn
O
BnO
1
2
3
4
5
6a,b
24
Galp (D)
4.82–
4.67
3.81– 5.09 (dd, 5.43 4.03– a:, b: 3.57–
3.72 J2,3 = 9.6, (d, J = 3.96 3.45 (m)a
(m)a J3,4 = 3.1) 2.7) (m)a 69.03
E
BnO
BnO
(m)a
O
a
b
87.48 (J 76.48 74.16
= 156.0)
68.47 75.39b
21
AcO
O
Galp (E)
4.82–
4.67
4.03– 3.84 (dd, 3.89 4.03– a: 3.57–
3.96 J2,3 = 10.1, (br s) 3.96 3.45 (m)a b:
(m)a J3,4 = 2.5) 75.32 (m)a 3.81–3.72
SPh
D
AcO
(m)a
ONAP
98.32 (J 69.42 78.84
75.08b (m)a 67.12
24 (60 %)
= 168.0)
Scheme 5. Reagents and conditions: (a) (i) HCl(aq), THF, 50 °C, 5 h; (ii) Ac2O,
pyridine, 0 °C?rt, overnight; (iii) chromatographic separation (n-hexane–ethyl
acetate 65:35).
a
Overlap.
b
Interchangeable assignments.

Z. B. Szabó et al. / Tetrahedron: Asymmetry 20 (2009) 808–820
813
Ph
OBn
Ph
OBn
O
O
BnO
BnO
BnO
O
O
A
O
O
O
O
O
A
OSE
O
B
OSE
B
BnO
H3C
O
NPhth
O
NHAc
a
H3C
BnO
O
C
O
C
O
24 +10
O
ONAP
D
O
ONAP
D
O
OBn
a
c
OBn
OAc
OH
BnO
1 (90 %)
25
b
OAc
O
OH
O
OBn
OBn
OBn
OBn
BnO
E
E
O
BnO
O
BnO
OBn
28 (82 % for three steps)
25 (43 %)
Ph
OBn
Ph
O
O
BnO
BnO OBn
O
O
O
O
O
O
A
A
O
O
OSE
B
OSE
B
BnO
BnO
H3C
O
NHAc
O
NPhth
H3C
O
C
O
C
O
OBn
OBn
a
BnO
NAPO
O
a
c
24 + 13
BnO
26
2 (85 %)
NAPO
D
O
b
HO
HO
D
O
AcO
AcO
O
O
BnO
BnO
BnO
E
BnO
E
O
OBn
O
BnO
BnO OBn
26 (50 %)
29 (78 % for three steps)
Ph
OBn
O
Ph
O
O
BnO
BnO
O
OBn
BnO
O
O
A
O
O
O
OSE
A
B
OSE
NHAc
O
B
BnO
H3C
O
NPhth
O
H3C
O
C O
OBn
O
C
OBn
a
OBn
a
c
24 +16
OBn
27
3 (90 %)
O
NAPO
b
NAPO
AcO
D
HO
D
O
O
AcO
HO
O
O
BnO
BnO
O
BnO
E
BnO
E
O
OBn
BnO
27 (50 %)
OBn
BnO
30 (82 % for three steps)
Scheme 6. Reagents and conditions: (a) NIS/AgOTf, DCM, ꢀ8 °C, 3 h.
Scheme 7. Reagents and conditions: (a) NH2NH2ÁH2O, EtOH, reflux, 28: 24 h, 29, 30:
5 h; (b) (i) Ac2O, pyridine, 0 °C?rt, overnight; (ii) NaOMe, MeOH–CH2Cl2, rt, 5 h; (c)
Pd(C), H2, EtOH–THF 2:1, rt, overnight.
the fully blocked pentasaccharides with hydrazine hydrate
cleaved the phthaloyl groups, and the resulting mixture was
acetylated in pyridine to introduce the N-acetyl residue. The
3,4-di-O-acetyl groups, present at the D unit, were removed by
the Zemplén method and compounds 28, 29 and 30 were iso-
lated (Scheme 7).
The residual benzyl, 2-naphthylmethyl- and benzylidene
groups were reduced under hydrogen pressure in the presence of
Pd/C catalyst, to give the target free pentasaccharides 1, 2 and 3.
The NMR data for the anomeric centres of compounds 25, 26, 27
and 1, 2, 3 are presented in Tables 4 and 5.
3. Conclusion
The planned isomeric pentasaccharides 1, 2 and 3 were success-
fully prepared in deblocked forms. Over the course of the synthetic
experiments known glycosylation methods and the 2-naphthyl-
methyl ether as
a temporary-protecting group were used.
Glycosylation reactions by using fucosyl donors bearing one O-
(2-naphthyl)methyl ether group at the 2-, 3- or 4-position and
benzyl groups at the other positions led to the formation of the

814
Z. B. Szabó et al. / Tetrahedron: Asymmetry 20 (2009) 808–820
concentrated in vacuum. The 1H (200.13, 360.13 and
500.13 MHz) and 13C NMR (50.3, 90.54 and 125.76 MHz) spectra
were recorded with Bruker AC-200, Bruker DRX-360 and Bruker
DRX-500 spectrometers in CDCl3 solutions. The use of a different
solvent is indicated therein. Chemical shifts are referenced to
Me4Si (0.00 ppm for 1H) or to the residual solvent signals
(77.00 ppm for 13C). The F2-coupled 1H–13C-HSQC experiments
were performed on Bruker DRX-500 spectrometer at 298 K.
Selected NMR-data of compounds 1–3, 6, 7, 9, 10, 12, 13, 15,
16, 24 and 25–27 are presented in Tables 1–5, included in
Section 2. Additional NMR signals of these compounds are given
below separately at each experiment.
MALDI-TOF MS analyses of the compounds were carried out in
the positive reflectron mode using a BIFLEX III mass spectrometer
(Bruker, Germany) equipped with delayed-ion extraction. The
matrix solution was a saturated 2,4,6-trihydroxy-acetophenone
(THAP) solution in MeCN. ESI-TOF MS analyses of the compounds
were carried out in the positive reflectron mode using a MicrO-
TOF-Q mass spectrometer (Bruker, Germany). Elemental analyses
were performed at the analytical laboratories of the University of
Debrecen.
Table 4
The 1H and 13C NMR data for the anomeric centres of compounds 25, 26 and 27
Compound Monosaccharide
unit/PG
1H NMR d (ppm) 3J1,2 13C NMR d (ppm)
(Hz)
1JC1,H1 (Hz)
25
26
27
D
-GlcNPhth (A)
-Galp (B)
5.11–5.05 (m)a
4.51–4.43 (m)a
5.49 (br s)
98.58 (J = 163.0)
99.98 (J = 161.0)
98.51 (J = 174.5)
96.90 (J = 173.5)
97.36 (J = 169.5)
100.50 (J = 161.0)
D
L
-Fucp (C)
D
-Galp (D)
-Galp (E)
5.72 (br s)
D
4.72–4.68 (m)a
5.57 (s)
Benzylidene acetal
D
-GlcNPhth (A)
-Galp (B)
5.33–5.29 (m)a
4.46–4.40 (m)a
5.49–5.43 (m)a
5.04–4.95 (m)a
4.82–4.75 (m)a
5.49–5.43 (m)a
98.14 (J = 164.0)
101.11 (J = 160.0)
97.91 (J = 173.0)
96.62 (J = 168.0)
98.75 (J = 168.0)
100.88 (J = 162.0)
D
L
-Fucp (C)
D
-Galp (D)
-Galp (E)
D
Benzylidene acetal
D
-GlcNPhth (A)
-Galp (B)
5.15 (d, J = 8.5)
4.51–4.39 (m)a
5.23 (d, J = 3.2)
5.82 (d, J = 3.8)
4.85–4.75 (m)a
5.55 (s)
98.43 (J = 164.0)
100.32 (J = 160.0)
97.45 (J = 171.5)
96.64 (J = 169.5)
99.31 (J = 168.0)
100.69 (J = 160.5)
D
L
-Fucp (C)
D
-Galp (D)
-Galp (E)
D
Benzylidene acetal
a
Overlap.
4.2. General method A for the coupling reaction using NIS-
TMSOTf activation
Table 5
The 1H and 13C NMR data for the anomeric centres of compounds 1, 2 and 3
To a solution of the disaccharide acceptor 7 (2.7 g, 2.9 mmol,
1.0 equiv) and the appropriate fucoside donor (7.25 mmol, 2.5
equiv) in dry DCM (80 mL), 4 Å molecular sieves (7.5 g) were added
and stirred for 3 h at room temperature. Then the solution was
cooled to ꢀ55 °C and a solution of NIS (9.3 mmol, 3.2 equiv) and
TMSOTf (1.8 mL, 0.63 equiv) in a mixture of dry THF (9 mL) and
dry DCM (5 mL) was added. The reaction mixture was kept at
ꢀ55 °C until TLC showed the disappearance of the acceptor (0.5–
3 h), after which it was quenched by the addition of pyridine
(0.5 mL) and allowed to warm up to room temperature. The mix-
ture was filtered, the filtrate was diluted with CH2Cl2, washed with
5% Na2S2O3 and with satd NaHCO3 solutions and with water. The
organic layer was dried and evaporated. The residue was then puri-
fied by column chromatography.
Compound Monosaccharide
unit/PG
1H NMR d (ppm) 3J1,2 13C NMR d (ppm)
(Hz)
1JC1,H1 (Hz)
1
2
3
D-GlcNAc (A)
D-Galp (B)
L-Fucp (C)
D-Galp (D)
D-Galp (E)
4.47 (d, J = 7.5)
4.28 (d, Jffi 8.5)
4.79 (d, J = 3.2)
5.13 (d, Jffi 2.2)
5.13 (d, Jffi 2.2)
4.52 (d, J = 7.6)
4.29 (d, J = 8.5)
4.83 (d, J = 3.6)
5.06 (d, J = 4.0)
5.08 (d, J = 3.8)
100.23 (J = 165.0)
101.35 (J = 160.5)
98.65 (J = 169.5)
99.50 (Jffi 174.5)*
99.71 (Jffi 174.5)*
100.22 (J = 164.0)
101.32 (J = 160.0)
98.99 (J = 169.5)
99.63 (J = 172.5)
101.42 (J = 171.0)
W
W
W
D-GlcNAc (A)
D-Galp (B)
L-Fucp (C)
D-Galp (D)
D-Galp (E)
D-GlcNAc (A)
D-Galp (B)
L-Fucp (C)
D-Galp (D)
D-Galp (E)
4.48 (d, J = 7.6)
4.29 (d, J = 8.5)
4.80 (d, J = 2.7)
100.43 (J = 164.5)
101.26 (J = 160.5)
98.94 (J = 171.0)
99.72 (J = 173.0)
102.03 (J = 170.0)
W
4.3. General method B for oxidative removal of O-(2-
naphthyl)methyl group
5.06
W
5.06
W
Overlap.
Interchangeable assignments
*
The starting material (1.6 mmol, 1.0 equiv) was dissolved in a
mixture of DCM and H2O (9:1, 140 mL) and freshly crystallized
DDQ (2.6 mmol, 1.6 equiv) was added. The reactions reached com-
pletion within 25 min. Next the mixture was diluted with CH2Cl2,
and washed three times with satd NaHCO3 solution. The organic
layer was dried and evaporated. The residue was then purified by
column chromatography.
three trisaccharides which could be used, after selective removal of
the 2-naphthylmethyl-protecting group—as acceptors in the 2+3
block syntheses of the target regioisomeric pentasaccharides. The
ONAP-protecting group was also present at the C-2 position of
two donor compounds and behaved as a non-participating group,
as was expected. The synthesized molecules are suitable for the
structure elucidation of the natural pentasaccharide.
4.4. General method C for coupling reaction using NIS-AgOTf
promoter
To a solution of the trisaccharide acceptors 10, 13 or 16
(1.7 mmol, 1.0 equiv) and the disaccharide donor 24 (2.7 mmol,
1.6 equiv) in dry DCM (50 mL), 4 Å molecular sieves (5 g) were
added and stirred for 3 h at room temperature, after which the
solution was cooled to ꢀ8 °C. A solution of NIS (3.51 mmol, 2.1
equiv) in dry THF (2.2 mL) and a solution of AgOTf (0.41 mmol,
0.24 equiv) in dry toluene (2.2 mL) were mixed and added into
the cooled reaction mixture. The reaction mixture was kept at
ꢀ8 °C until TLC showed completion of the reaction (0.5–3 h). Then
it was neutralized by the addition of pyridine (0.5 mL) and allowed
to warm up to room temperature. The mixture was diluted with
CH2Cl2 and filtered through a pad of Celite. The filtrate was washed
4. Experimental
4.1. General methods
Optical rotations were measured at room temperature with a
Perkin–Elmer 241 automatic polarimeter. TLC was performed on
Kieselgel 60 F254 (Merck) with detection by immersing into 5%
ethanolic sulfuric acid solution followed by heating. Column
chromatography was performed on Silica Gel 60 (Merck 0.063–
0.200 mm). Organic solutions were dried over MgSO4, and

Z. B. Szabó et al. / Tetrahedron: Asymmetry 20 (2009) 808–820
815
with 5% Na2S2O3 and satd NaHCO3 solutions and with water. The
organic layer was dried and evaporated. The residue was then puri-
fied by column chromatography.
4.8. (2-Trimethylsilyl)ethyl 3,4,6-tri-O-benzyl-b-
galactopyranosyl-(1?3)-4,6-O-benzylidene-2-deoxy-2-
phthalimido-b- -glucopyranoside 7
D-
D
4.5. General method D for conversion of N-phthaloyl-group
into N-acetyl group
To a solution of 6 (16.930 g, 17 mmol) in a mixture of DCM–
MeOH = 1:2 (350 ml) 1 M methanolic NaOMe solution was added
(32 ml) and it was stirred overnight. Then another portion of meth-
anolic NaOMe (25 ml) was added. The reaction was monitored by
TLC (DCM–acetone = 97:3), the disappearance of the starting mate-
rial required 5 days. The mixture was neutralized with Amberlite
IR-120 H+ ion exchange resin, filtered and evaporated. The residue
was dissolved in dry pyridine (300 ml), cooled in an ice bath and
trifluoroacetic anhydride was added dropwise. After 45 min TLC
showed the formation of a product of high mobility. (DCM–acetone
= 97:3, Rf = 0.81). The mixture was diluted with dichloromethane,
washed with water (400 mL), with 10% aq CuSO4 (400 mL), with
1 M HCl solution (2 Â 300 mL), water (300 mL) then washed until
neutral pH with satd NaHCO3 solution and water. The solution
was dried and evaporated, and the 2-O-trifluoroacetylated inter-
mediate was analyzed by ESI-TOF: m/z calcd for C55H58F3NO13Si
(1026.13) [M+H]+: 1026.370. Measured: 1026.372).
Dephthaloylation step: To a solution of the starting material
(0.14 mmol) in abs EtOH (7 mL) hydrazine-hydrate was added
(1 mL) and the mixture was refluxed overnight. The presence of
the free amine was detected with TLC by immersing into 1% etha-
nolic ninhydrine solution followed by heating. The solvent was
evaporated in vacuo and co-evaporated with toluene. Acetylation
step: the residue obtained was dissolved in pyridine (5 mL) and
acetic anhydride (5 mL) was added at 0 °C. After 10 h the mixture
was evaporated in vacuo and co-evaporated with toluene. The res-
idue was diluted with CH2Cl2, washed with 10% aq citric acid solu-
tion, with water and satd NaHCO3 solution, then with water again.
The organic layer was dried and evaporated.
O-Deacetylation step: For the removal of the O-acetyl groups
present in the molecule the crude material was dissolved in a 1:2
mixture of DCM–MeOH (6 mL) and was treated with catalytic
amount of NaOMe (ꢁ20 mg). After complete conversion the mix-
ture was neutralized with Amberlite IR-120 H+ ion exchange resin,
filtered and evaporated. The residue was purified by column
chromatography.
The crude product was dissolved in a 1:2 mixture of DCM–
MeOH (350 mL) and treated with 1 M methanolic NaOMe
(6 Â 1 mL), the reaction was monitored by TLC (DCM–acetone =
98:2, Rf = 0.39). After complete conversion of the trifluoroacetylat-
ed intermediate the mixture was neutralized with Amberlite IR-
120 H+ ion exchange resin, filtered and evaporated. The syrupy res-
idue was purified by column chromatography (DCM–EtOAc = 95:5)
4.6. General method E for catalytic hydrogenation
to yield 7 as a white foam (9.070 g, 56%), ½a D25
¼ ꢀ48:5 (c 0.24,
Š
To a solution of the starting material (0.07 mmol) in a mixture
of 96% EtOH (2 mL) and THF (1 mL) in an autoclave 10% Pd/C
(0.100 g) was added. The autoclave was degassed by applying vac-
uum and filled with 26 bar pressure of hydrogen. After overnight of
vigorous stirring TLC showed complete conversion. The catalyst
was removed by filtration through Celite and was washed twice
with aq MeOH. The filtrate was evaporated and the crude product
was purified by column chromatography.
CHCl3). 1H NMR (500 MHz) d (ppm) 7.75 (br s, 1H, arom.), 7.57–
7.45 (m, 5H, arom.), 7.40–7.16 (m, 17H, arom.), 7.11–7.06 (m, 2H,
1
arom.), 5.60 (s, 1H, JC,H = 164.0 Hz, Hacetalic), 4.93 (d, 1H, Jgem
=
11.9 Hz, PhCHH), 4.52 (q, 2H, PhCH2), 4.44 (d, Jgem = 11.9 Hz, 1H,
PhCHH), 4.02 (q, 2H, PhCH2), 3.97–3.88 (m, 2H, OCHHCH2Si, H-
20), 3.49 (ddd, 1H, OCHHCH2Si), 3.27–3.18 (m, 3H, OH, H-5, H-300),
0.86–0.77 (m, 1H, CHHSi), 0.76–0.69 (m, 1H, CHHSi), –0.14 (s, 9H,
Si(CH3)3). 13C NMR
d (ppm) 168.18, 167.49 (C@O), 139.24,
138.60, 137.77, 136.23, 132.06 (Cq, arom.), 133.50, 129.34,
128.27, 128.08, 128.01, 127.57, 127.37, 127.24, 127.06, 126.25,
123.15 (Carom.), 102.11 (Cacetalic), 74.47, 72.87, 72.50 (PhCH2),
67.32 (OCH2CH2Si), 17.77 (CH2Si), ꢀ1.60 (Si(CH3)3). ESI-TOF: m/z
calcd for C53H59NO12Si (930.1) [M+Na]+: 952.370. Measured:
952.373.
4.7. (2-Trimethylsilyl)ethyl 2-O-acetyl-3,4,6-tri-O-benzyl-b-
galactopyranosyl-(1?3)-4,6-O-benzylidene-2-deoxy-2-
D-
phthalimido-b-
D-glucopyranoside 6
To
a
solution of donor 413 (18.022 g) and acceptor 514
(12.036 g) in dry dichloromethane (250 mL) 4 Å powdered
molecular sieves (18.5 g) and sym-collidine (4.4 mL) were added
and the mixture was stirred for 30 min in the dark. Then it was
cooled into ꢀ74 °C and AgOTf (10.900 g) in dry toluene (120 mL)
was added. After overnight stirring, the mixture was diluted
with dichloromethane, filtered through a pad of Celite, evapo-
rated in vacuo, and the residue was purified by column chroma-
tography (n-hexane–EtOAc = 67:33) to yield 6 as a white foam
4.9. (2-Trimethylsilyl)ethyl 3,4-di-O-benzyl-2-O-(2-naphthyl)
methyl-a-L-fucopyranosyl-(1?2)-3,4,6-tri-O-benzyl-b-D-galacto-
pyranosyl-(1?3)-4,6-O-benzylidene-2-deoxy-2-phthalimido-b-
D-glucopyranoside 9
Compound 8 (4.063 g, 7.194 mmol) was reacted with 7 (2.669 g,
2.869 mmol) according to general method A at ꢀ55 °C. T.l.c: DCM–
acetone 99:1, Rf = 0.54. Purification of the crude product by column
chromatography (n-hexane–ethylacetate 7:3) afforded 9 as a foam
(16.930 g, 72%), Rf = 0.47, [
a]
D = ꢀ6.1 (c 0.16, CHCl3). 1H NMR
(500 MHz) d (ppm) 7.85 (br s, 2H, arom.), 7.75–7.71 (m, 2H,
arom.), 7.48–7.44 (m, 2H, arom.), 7.34–7.11 (m, 18H, arom.),
(2.406 g, 60%); [
a
]
D = ꢀ37.7 (c 0.13, CHCl3); 1H NMR (500 MHz) d
1
5.51 (s, 1H, JC,H
=
162.5 Hz, Hacetalic), 4.80 (d, 1H, Jgem
=
(ppm) 7.71 (d, 1H, arom.), 7.65 (br s, 1H, arom.) 7.52–7.44 (m,
11.7 Hz, PhCHH), 4.51–4.45 (m, 2H, 2 Â PhCHH), 4.19 (q, 2H,
PhCH2), 3.89 (ddd, 1H, OCHHCH2Si), 3.46 (ddd, 1H, OCHHCH2Si),
2.14 (s, 3H, COCH3), 0.81–0.73 (m, 1H, CHHSi), 0.73–0.66 (m, 1H,
CHHSi), ꢀ0.15 (s, 9H, Si(CH3)3). 13C NMR d (ppm) 168.74 (C@O),
138.41, 137.86, 137.70, 137.38 (Cq, arom.), 128.87, 128.28,
128.12, 128.06, 127.99, 127.94, 127.85, 127.69, 127.36, 127.27,
126.97, 126.05 (Carom.), 101.10 (Cacetalic), 74.27, 73.34, 71.46
(PhCH2), 67.10 (OCH2CH2Si), 20.24 (CH3CO), 17.74 (OCH2CH2Si),
ꢀ1.64 (Si(CH3)3). ESI-TOF: m/z calcd for C55H61NO13Si (972.16)
[M+Na]+: 994.383. Measured: 994.383.
6H, arom.), 7.41–7.14 (m, 33H, arom.), 7.02 (dd, 1H, arom.), 4.87–
4.75 (m, 4H, ArCH2), 4.62 (s, 2H, ArCH2), 4.55 (d, 2H, Jgem
=
11.1 Hz, ArCHH), 4.50–4.46 (m, 2H, ArCHH, H-1’), 4.42–4.27 (m,
6H, H-400, H-500, H-6a, H-2, ArCHH), 3.90–3.84 (m, 2H, H-400,
OCHHCH2Si), 3.44 (ddd, 1H, OCHHCH2Si), 0.76–0.63 (m, 2H, CH2Si),
ꢀ0.15 (s, 9H, Si(CH3)3). 13C NMR d (ppm) 139.15, 138.89, 138.59,
138.33, 137.74, 137.38, 135.68, 132.98, 132.60, 131.47 (Cq, arom.),
128.51, 128.32, 128.24, 128.17, 128.01, 127.99, 127.90, 127.83,
127.76, 127.69, 127.44, 127.39, 127.31, 127.20, 127.18, 127.10,
127.04, 126.14, 126.07, 125.68, 125.50, 125.32, 123.47 (Carom.),

816
Z. B. Szabó et al. / Tetrahedron: Asymmetry 20 (2009) 808–820
75.00, 74.31, 73.53, 72.60, 71.80, 71.22 (ArCH2), 67.26 (OCH2CH2-
Si), 17.87 (CH2Si), –1.67 (Si(CH3)3). ESI-TOF: m/z calcd for
C84H89NO16Si (1395.595) [M+Na]+: 1418.585. Found 1418.642.
Calcd for [M+2Na]2+: 720.787. Found: 720.786.
4.39–4.26 (m, 4H, H-6a, H-2, PhCHH), 3.96 (d, 1H, Jgem = 12.2 Hz,
PhCHH), 3.88 (ddd, 1H, OCHHCH2Si), 3.44 (ddd, 1H, OCHHCH2Si),
0.79–0.64 (m, 2H, CH2Si), –0.14 (s, 9H, Si(CH3)3). 13C NMR d (ppm)
138.85, 138.64, 138.23, 138.08, 137.85, 137.45, 131.53 (Cq, arom.),
134.00, 128.55, 128.21, 128.13, 128.03, 127.92, 127.74, 127.66,
127.51, 127.44, 127.29, 127.21, 127.06, 126.25, 126.12, 123.48 (Car-
om.), 75.55, 74.30, 73.50, 71.21, 71.16 (PhCH2), 67.22 (OCH2CH2Si),
17.86 (CH2Si), –1.64 (Si(CH3)3). Anal. Calcd for C73H81NO16Si
(1256.51): C, 69.78; H, 6.50. Found: C, 69.55; H, 6.52. MALDI-TOF:
m/z calcd for [M+Na]+: 1278.522. Found 1278.314.
4.10. (2-Trimethylsilyl)ethyl 3,4-di-O-benzyl-
(1?2)-3,4,6-tri-O-benzyl-b- -galactopyranosyl-(1?3)-4,6-O-
benzylidene-2-deoxy-2-phthalimido-b- -glucopyranoside 10
a-L-fucopyranosyl-
D
D
Trisaccharide 9 (2.250 g, 1.61 mmol) was treated with DDQ
according to general method B. Purification of the crude product
by column chromatography (DCM–acetone 99:1, Rf
=
0.60)
4.13. (2-Trimethylsilyl)ethyl 2,3-di-O-benzyl-4-O-(2-naphthyl)
methyl-a-L-fucopyranosyl-(1?2)-3,4,6-tri-O-benzyl-b-D-galactopy-
ranosyl-(1?3)-4,6-O-benzylidene-2-deoxy-2-phthalimido-b-D-
glucopyranoside 15
afforded 10 as a foam (1.518 g, 75%); [
a
]
D = ꢀ47.4 (c 0.15); 1H
NMR (500 MHz) d (ppm) 7.62 (br s, 2H, arom.), 7.45 (d, 2H, arom.),
7.37–7.18 (m, 30H, arom.), 4.81–4.73 (m, 4H, 3-H, H1–100, PhCHH),
4.58–4.41 (m, 7H, H-10, 3 Â PhCH2), 4.36–4.23 (m, 4H, 2-H, H-6a,
PhCHH), 3.91–3.75 (m, 5H, H-20, H-40, H-4, H-6b, OCHHCH2Si),
3.50–3.43 (m, 2H, H-60b, OCHHCH2Si), 0.75, 0.68 (m, 2H, CHHSi),
Compound 14 (3.795 g, 6.720 mmol) was reacted with
7
(2.500 g, 2.687 mmol) according to general method A at ꢀ58 °C.
Purification of the crude product by column chromatography (n-
hexane–ethyl acetate 7:3, Rf = 0.60) afforded 15 as a foam
–0.16 (Si(CH3)3). 13C NMR
d (ppm) 139.02, 138.74, 138.35,
137.63, 137.42, 137.23 (Cq, arom.), 133.66, 128.71, 128.38,
128.34, 128.31, 128.14, 128.08, 128.04, 128.00, 127.96, 127.89,
127.73, 127.63, 127.45, 127.34, 127.23, 127.19, 127.12, 126.05 (Car-
om.), 74.92, 74.30, 73.45, 72.31, 71.75 (PhCH2), 67.13 (OCH2CH2Si),
17.77 (CH2Si), ꢀ1.65 (Si(CH3)3). Anal. Calcd for C73H81NO16Si
(1256.51): C, 69.78; H, 6.50. Found: C, 69.95; H, 6.47. MALDI-
TOF: m/z calcd for [M+Na]+: 1278.522. Found 1278.620.
(2.328 g, 62%); [
a]
D = ꢀ40.5 (c 0.22, CHCl3). 1H NMR (500 MHz) d
(ppm) 7.83–7.74 (m, 4H, arom.), 7.64 (br s, 2H, arom.), 7.52–7.41
(m, 7H, arom.), 7.37–7.11 (m, 24H, arom.), 7.06 (t, 2H, arom.),
7.00 (d, 2H, arom.), 5.03–4.97 (m, 2H, 3-H, ArCHH), 4.80–4.69 (m,
4H, ArCH2), 4.58 (q, 2H, ArCH2), 4.49–4.45 (m, 2H, H-10, ArCHH),
4.42–4.37 (m, 2H, ArCHH), 4.36–4.25 (m, 5H, H-6a, H-500, H-2,
ArCHH), 3.86 (ddd, 1H, OCHHCH2Si), 3.47–3.41 (m, 2H, H-30,
OCHHCH2Si), 0.75–0.62 (m, 2H, CHHSi), ꢀ0.16 (s, 9H, Si(CH3)3).
13C NMR d (ppm) 139.23, 138.67, 138.38, 137.85, 137.46, 136.59,
133.17, 132.89, 131.55 (Cq, arom.), 133.97, 128.54, 128.32,
128.20, 128.12, 128.01, 127.96, 127.93, 127.86, 127.74, 127.67,
127.58, 127.50, 127.20, 127.15, 127.09, 127.01, 126.97, 126.69,
126.56, 126.31, 126.11, 125.79, 125.59, 123.43 (Carom.), 74.97,
74.31, 73.54, 72.66, 72.16, 71.52 (ArCH2), 67.21 (OCH2CH2Si),
17.89 (CH2Si), ꢀ1.66 (SiCH3)3). Anal. Calcd for C84H89NO16Si
(1396.69): C, 72.24; H, 6.42. Found: C, 72.08; H, 6.44. MALDI-
TOF: m/z calcd for (M+Na)+: 1418.584. Found 1418.654.
4.11. (2-Trimethylsilyl)ethyl 2,4-di-O-benzyl-3-O-(2-naphthyl)
methyl-a-L-fucopyranosyl-(1?2)-3,4,6-tri-O-benzyl-b-D-galactopy-
ranosyl-(1?3)-4,6-O-benzylidene-2-deoxy-2-phthalimido-b-D-
glucopyranoside 12
Compound 11 (3.795 g, 6.719 mmol) was reacted with 7 (2.500 g,
2.687 mmol) according to general method A at ꢀ58 °C. Purification
of the crude product by column chromatography (n-hexane–ethyl
acetate 7:3, Rf = 0.60) afforded 12 as a foam (2.570 g, 68%);
[
a
]
D = ꢀ33.8 (c 0.21, CHCl3); 1H NMR (500 MHz) d (ppm) 7.82–7.73
(m, 3H, arom.), 7.64–7.58 (d, 3H, arom.), 7.49, (d, 2H, arom.), 7.46–
7.00 (m, 33H, arom.), 4.93–4.87 (m, 2H, ArCHH), 4.83 (d, 1H, Jgem
=
4.14. (2-Trimethylsilyl)ethyl 2,3-di-O-benzyl-
(1?2)-3,4,6-tri-O-benzyl-b- -galactopyranosyl-(1?3)-4,6-O-
benzylidene-2-deoxy-2-phthalimido-b- -glucopyranoside 16
a-L-fucopyranosyl-
12.3 Hz, ArCHH), 4.79 (d, 1H, Jgem = 11.6 Hz, ArCHH), 4.63–4.54 (m,
3H, ArCHH), 4.49–4.36 (m, 4H, H-10, H-400, ArCHH), 4.36–4.23 (m,
5H, H-2, H-500, H-6a, ArCHH), 3.87 (ddd, 1H, OCHHCH2Si), 3.48–
3.41 (m, 2H, H-30, OCHHCH2Si), 0.77–0.63 (m, 2H, CH2Si), ꢀ0.15 (s,
9H, Si(CH3)3). 13C NMR d (ppm) 139.10, 138.69, 138.45, 138.39,
137.87, 137.48, 136.79, 133.28, 132.71, 131.55 (Cq, arom.), 133.96,
128.56, 128.34, 128.29, 128.14, 128.10, 128.04, 127.98, 127.89,
127.83, 127.68, 127.53, 127.41, 127.22, 127.04, 126.99, 126.36,
126.12, 125.89, 125.57, 125.50, 125.30. 123.47 (Carom.), 75.08,
74.33, 73.55, 72.50, 72.07, 71.60 (ArCH2), 67.25 (OCH2CH2Si), 17.92
(CH2Si), ꢀ1.63 (Si(CH3)3). Anal. Calcd for C84H89NO16Si (1396.69):
C, 72.24; H, 6.42. Found: C, 72.50; H, 6.39. MALDI-TOF: m/z calcd
for [M+Na]+: 1418.584. Found 1418.590.
D
D
Trisaccharide 15 (2.000 g, 1.431 mmol) was treated with DDQ
according to general method B. Purification of the crude product
by column chromatography (DCM–acetone 98:2) afforded 16 as a
foam (1.350 g, 75%); Rf = 0.39 (n-hexane–ethyl acetate 7:3);
[a]
D = ꢀ34.2 (c 0.16). 1H NMR (500 MHz) d (ppm) 7.78–7.62 (m,
4H, arom.), 7.50 (d, 2H, arom.), 7.34–7.06 (m, 26H, arom.), 6.98
(d, 2H, arom.), 4.79 (d, 1H, Jgem. = 11.7 Hz, PhCHH), 4.67 (s, 2H,
PhCH2), 4.54 (q, 2H, PhCH2), 4.48 (d, 1H, Jgem = 11.7 Hz, PhCHH),
4.45–4.25 (m, 8H, H-10, H-2, H-6a, H-500, PhCHH), 3.89 (ddd, 1H,
OCHHCH2Si), 3.46 (ddd, 1H, OCHHCH2Si), 0.79–0.64 (m, 2H, CH2Si),
ꢀ0.14 (s, 9H, Si(CH3)3). 13C NMR d (ppm) 138.62, 138.46, 138.30,
138.23, 137.80, 137.43, 131.62 (Cq, arom.), 134.04, 128.51,
128.28, 128.09, 128.00, 127.91, 127.85, 127.75, 127.64, 127.46,
127.29, 127.18, 127.01, 126.26, 126.07, 123.37 (Carom.), 74.28,
73.50, 71.99, 71.83, 71.36 (PhCH2), 67.21 (OCH2CH2Si), 17.84
(CH2Si), –1.66 (Si(CH3)3). Anal. Calcd for C73H81NO16Si (1256.51):
C, 69.78; H, 6.50. Found: C, 69.50; H, 6.46. MALDI-TOF: m/z calcd
for [M+Na]+: 1278.522. Found 1278.368.
4.12. (2-Trimethylsilyl)ethyl 2,4-di-O-benzyl-
(1?2)-3,4,6-tri-O-benzyl-b- -galactopyranosyl-(1?3)-4,6-O-
benzylidene-2-deoxy-2-phthalimido-b- -glucopyranoside 13
a-L-fucopyranosyl-
D
D
Trisaccharide 12 (2.550 g, 1.825 mmol) was treated with DDQ
according to general method B. Purification of the crude product
by column chromatography (DCM–acetone 99:1) afforded 13 as a
foam (1.562 g, 77%); Rf = 0.39 (n-hexane–ethyl acetate 7:3); [a] =
D
ꢀ61.0 (c 0.12, CHCl3). 1H NMR (500 MHz) d (ppm) 7.77 (br s, 2H,
arom.), 7.56 (br s, 2H, arom.), 7.49 (d, 2H, arom.), 7.36–7.13 (m,
26H, arom.), 6.95 (d, 2H, arom.), 4.78 (d, 1H, Jgem = 11.6 Hz, PhCHH),
4.71 (d, 1H, Jgem = 11.4 Hz, PhCHH), 4.63–4.58 (m, 2H, PhCHH), 4.48
(d, 1H, Jgem = 11.6 Hz, PhCHH), 4.45–4.39 (m, 3H, H-10, PhCHH),
4.15. Phenyl 3,4-O-isopropylidene-6-O-(methoxydimethyl)
methyl-2-O-(2-naphthyl)methyl-1-thio-b-D-galactopyranoside 18
Compound 1715 (3.340 g, 8.7 mmol) was dissolved in dry DMF
(15 mL) and cooled to 0 °C. NaH (13.0 mmol, 1.5 equiv, 60%,

Z. B. Szabó et al. / Tetrahedron: Asymmetry 20 (2009) 808–820
817
previously treated with hexane) was added carefully to the
mixture and stirred for half an hour. Then 2-bromomethylnaph-
thalene (1.923 g, 10.44 mmol, 1.2 equiv) was added. The reaction
reached completion within 3 h. The excess of NaH was decom-
posed by the addition of MeOH and the solvent was evaporated
in vacuo. The residue was dissolved in DCM, extracted three
times with water, then the organic layer was dried and evapo-
rated. Column chromatographic purification (DCM–acetone 99:1
7.58 mmol, 1.5 equiv) in dry DMF (40 mL) were added and the
mixture was allowed to warm up to room temperture slowly.
The reaction took place within 24 h. The mixture was diluted with
CH2Cl2 and filtered through a pad of Celite, the filtrate was washed
with 5% Na2S2O3 and with satd NaHCO3 solutions then with water.
The organic layer was dried and evaporated. The residue was then
purified by column chromatography to give 21 as a colourless oil
(2.347 g, 68%); Rf
= 0.60 (n-hexane–ethyl acetate 65:35);
+1% Et3N) afforded 18 as a colourless oil (4.298 g, 94%); Rf
=
[a]
D = +26.7 (c 1.05, CHCl3); 1H NMR (360 MHz) d (ppm) 7.84–
0.46 (DCM–acetone 98:2 +1% Et3N); [ D = +2.7 (c 1.01, CHCl3);
a
]
7.11 (m, 32H, arom.), 4.91–3.43 (m, 24H, skeleton Hs, 5 Â Ph-
CH2), 1.32, 1.30 (2s, 6H, Ip-CH3). 13C NMR d (ppm) 138.79,
138.61, 138.05, 135.15, 133.88, 133.12, 133.00, 131.48, 130.60,
128.69, 128.28, 128.13, 127.98, 127.84, 127.69, 127.60, 127.78 (Car-
om.), 110.07 (Cacetalic), 97.76 (C-10), 85.80 (C-1), 79.67, 79.08, 77.85,
76.47, 75.02, 73.48, 73.20, 68.92 (skeleton Cs), 74.79, 73.47, 73.20,
73.12, 72.95 (ArCH2), 68.68 (C-6), 67.31 (C-60), 27.72, 26.37 (Ip
CH3). Anal. Calcd for C60H62O10S (975.19): C, 73.90; H, 6.41; S,
3.29. Found: C, 74.18; H, 6.38; S, 3.31. MALDI-TOF: m/z calcd for
[M+Na]+: 997.396. Found: 997.343.
1H NMR (200 MHz, CDCl3 + TEA) d (ppm) 7.84–7.53 (m, 7H,
arom.), 7.47–7.21 (m, 5H, arom.), 4.89 (q, 2H, Jgem = 11.3 Hz,
ArCH2), 4.67 (d, 1H, J1,2 = 9.5 Hz, H-1), 4.28 (t, 1H, J = 5.8 Hz),
4.20 (dd, 1H), 3.86 (m, 1H), 3.66 (m, 3H), 3.17 (s, 3H, OCH3),
1.36, 1.34, 1.33 (3s, 12H, 4 Â CH3). 13C NMR d (ppm) 135.26,
134.10, 133.17, 133.03, 131.52, 128.60, 127.96, 127.83, 127.56,
127.03, 126.26, 125.87, 125.75 (Carom.), 109.97 (Cacetalic), 100.00
(MIP-Cacetalic), 86.04 (C-1), 79.73, 78.06, 75.73, 73.83 (skeleton
Cs), 73.31 (ArCH2), 60.21 (C-6), 48.45 (OCH3), 27.66, 26.17 (IP
CH3), 24.28 (MIP CH3); Anal. Calcd for C30H36O6S (524.16): C,
54.72; H, 6.34; S, 6.96. Found: C, 54.51; H, 6.37; S 6.92.
4.18. Phenyl 2,3,4,6-tetra-O-benzyl-a-D-galactopyranosyl-
(1?6)-3,4-di-O-acetyl-2-O-(2-naphthyl)methyl-1-thio-b-D-
4.16. Phenyl 3,4-O-isopropylidene-2-O-(2-naphthyl)methyl-1-
galactopyranoside 24
thio-b-D-galactopyranoside 19
Compound 21 (2.248 g, 2.22 mmol) was dissolved in THF
(15 mL) and a mixture of concd HCl–H2O (1:3, 0.68 mL) was added.
The mixture was kept at 45 sC for 5 h. Then the mixture was di-
luted with DCM, washed with satd NaHCO3 solution and with
water, the organic layer was dried and evaporated. The residue
was then purified by column chromatography (DCM–MeOH 97:3)
to give the diol intermediate as a colourless oil (1.795 g, 91%); Rf
= 0.26 (n-hexane–ethyl acetate 65:35); 1H NMR (360 MHz) d
(ppm) 7.81–7.03 (m, 32H, arom.), 5.05–3.28 (m, 24H, skeleton
Hs, 5 Â Ph-CH2), 2.61 (s, 2H, 2 Â OH). 13C NMR d (ppm) 138.52,
138.41, 138.06, 137.88, 135.56, 134.06, 133.18, 132.98, 131.63,
131.21, 128.84, 128.31, 128.12, 128.01, 127.90, 127.75, 127.69,
127.60, 127.51, 127.28, 126.95, 126.16, 125.98, 125.84 (Carom.),
98.52 (C-10), 87.66 (C-1), 78.79, 78.32, 76.37, 76.18 75.06, 74.71,
73.53, 69.44 (skeleton Cs), 75.38, 73.30, 72.82, (ArCH2), 68.77 (C-
60), 67.78 (C-6). Anal. Calcd for C57H58O10S (935.13): C, 73.21; H,
6.25; S, 3.43. Found: C, 73.25; H, 6.23; S, 3.41. MALDI-TOF: m/z
calcd for [M+Na]+: 957.364. Found: 956.257.
To a solution of 18 (4.200 g, 0.001 mol) in DCM (71 mL) acetic
acid (96%, 5.7 mL) and water (0.08 mL) were added and the mix-
ture was kept at 55 sC under reflux conditions. After completion
of the reaction (2.5 h) the mixture was diluted with DCM,
washed with satd NaHCO3 solution, dried and evaporated. Col-
umn chromatographic purification (DCM–acetone 9:1) afforded
19 as a colourless oil (3.231 g, 84%); Rf = 0.29 (DCM–acetone
97:3 +1% Et3N);
(200 MHz, CDCl3 + 1% TEA) d (ppm) 7.84–7.22 (m, 12H, arom.),
4.89 (q, 2H, Jgem = 11.3 Hz, ArCH2), 4.65 (d, 1H, J1,2 = 9.5 Hz, H-
[a]
D = +12.8 (c 1.03, CHCl3); 1H NMR
1), 4.27 (t, 1H, J = 5,8 Hz), 4.12 (dd, 1H, JA = 5.4 Hz, JB
1.4 Hz, H-4), 3.84 (m, 3H, H-5, H-6a,b), 3.55 (dd, 1H, JA
=
=
9.5 Hz, JB = 6.2 Hz), 2.31 (s, 1H, OH), 1.34, 1.32 (2s, CH3). 13C
NMR d (ppm) 135.16, 133.37, 133.15, 133.00, 131.83, 128.80,
127.97, 127.85, 127.59, 127.42, 127.01, 126.23, 125.94, 125.82
(Carom.), 110.21 (Cacetalic), 85.80 (C-1), 79.66, 78.06, 76.70, 73.79
(skeleton Cs), 73.33 (ArCH2), 62.40 (C-6), 27.59, 26.20 (Ip CH3).
Anal. Calcd for C26H28O5S (452.57): C, 52.51; H, 5.44; S, 8.25.
Found: C, 52.28; H, 5.41; S, 8.29.
To a solution of the diol intermediate (1.700 g, 1.78 mmol) in
pyridine (15 mL) acetic anhydride was added (8 mL) and the
mixture was stirred overnight. Then the mixture was evaporated
in vacuo and co-evaporated with toluene. The residue was di-
luted with CH2Cl2 washed with satd NaHCO3 solution, the organ-
ic layer was dried and evaporated. The residue was then purified
by column chromatography to give 24 as colourless oil (1.112 g,
4.17. Phenyl 2,3,4,6-tetra-O-benzyl-a,b-D-galactopyranosyl-
(1?6)-3,4-O-isopropylidene-2-O-(2-naphthyl)methyl-1-thio-b-
D
-galactopyranoside 21
Glycosylation with the imidate donor 20: To a solution of 19
60%); Rf = 0.48 (n-hexane–ethyl acetate 65:35); [
a
]
= +28.2 (c
D
(1.596 g, 3.64 mmol) and freshly prepared 2016 (3.323 g,
4.91 mmol, 1.35 equiv) in dry DCM (30 mL) 4 Å molecular sieves
(4.0 g) were added and the mixture was stirred for 2 h under Ar-
0.99, CHCl3). 1H NMR (500 MHz) d (ppm) 7.82–7.76 (m, 3H,
arom.), 7.70 (s, 1H, arom.), 7.58 (d, 2H, arom.), 7.48–7.42 (m,
3H, arom.), 7.40–7.19 (m, 23H, arom.), 4.50 (d, 1H, Jgem
=
gon. Then it was cooled to ꢀ30 °C and TMSOTf (117
l
l, 0.18
11.3 Hz, ArCHH), 4.92 (d, 1H, Jgem = 11.4 Hz, ArCHH), 4.80 (d,
1H, Jgem = 11.6 Hz, PhCHH), 4.78–4.71 (m, 4H, H-1, H-10, ArCH2),
4.70 (d, 1H, Jgem = 11.6 Hz, ArCHH), 4.64 (d, 1H, Jgem = 11.8 Hz,
ArCHH), 4.55 (d, 1H, Jgem = 11.4 Hz, ArCHH), 4.43 (q, 2H, ArCH2),
2.00, 1.87 (2s, 6H, COCH3). 13C NMR d (ppm) 170.08, 169.73
(C@O), 138.84, 138.59, 138.39, 138.09, 135.29, 133.55, 133.15,
132.95 (Cq, arom.), 131.69, 128.86, 128.30, 128.25, 128.13,
128.07, 128.00, 127.81, 127.73, 127.67, 127.60, 127.48, 127.42,
127.38, 127.30, 126.50, 126.06, 125.91, 125.83 (Carom.), 75.37,
74.69, 73.47, 73.22, 73.17 (ArCH2), 20.64, 20.60 (COCH3). Anal.
Calcd for C61H62O12S (1019.20): C, 71.88; H, 6.13; S, 3.15. Found:
C, 71.92; H, 6.10; S, 3.13. MALDI-TOF: m/z calcd for [M+Na]+:
1041.385. Found 1041.671.
equiv) in dry DCM (6 mL) was added. After completion of the
reaction (1.5 h) it was quenched by the addition of Et3N
(0.2 mL), the mixture was diluted with DCM, filtered and evapo-
rated. Column chromatographic purification afforded 21 as a col-
ourless oil (3.077 g, 88%); Rf = 0.60 (n-hexane–ethyl acetate
65:35).
Glycosylation with the bromosugar donor 23: To a stirred solution
of 2217 (3.200 g, 5.06 mmol, 1.0 equiv) in DCM (50 mL) at 0 °C Br2
(245 ll, 4.800 mmol, 0.95 equiv) was added. After complete conver-
sion of 22 4 AÅ powdered molecular sieves (5 g) were added into the
mixture and stirred for another half an hour at 0 sC. Then com-
pound 19 (1.585 g, 3.52 mmol, 0.7 equiv) and Bu4NBr (2.453 g,

818
Z. B. Szabó et al. / Tetrahedron: Asymmetry 20 (2009) 808–820
4.19. (2-Trimethylsilyl)ethyl 2,3,4,6-tetra-O-benzyl-
galactopyranosyl-(1?6)-3,4-di-O-acetyl-2-O-(2-naphthyl)methyl-
-galactopyranosyl-(1?2)-3,4-di-O-benzyl- -fucopyranosyl-
(1?2)-3,4,6-tri-O-benzyl-b- -galactopyranosyl-(1?3)-4,6-O-
benzylidene-2-deoxy-2-phthalimido-b- -glucopyranoside 25
a
-
D
-
74.38, 73.43, 73.10, 72.73, 72.64, 70.91, 70.87, 69.06, 68.71, 68.62,
67.16, 66.99 (OCH2), 55.89 (C-2), 20.74, 20.52 (COCH3), 17.83 (CH2Si),
17.00 (C-600), –1.68 (Si(CH3)3). Anal. Calcd for C128H137NO28Si
(2165.53): C, 70.75; H, 6.42. Found: C, 70.69; H, 6.44. MALDI-TOF:
m/z calcd for [M+Na]+: 2186.899. Found: 2187.079.
a-D
a-L
D
D
Compound 24 (0.521 g, 0.511 mmol) was reacted with 10
(0.428 g, 0.340 mmol) according to general method C at ꢀ5 °C. Puri-
fication of the crude product by column chromatography ((1) DCM–
acetone 98:2; (2) n-hexane–ethyl acetate 65:35) afforded 25 as a
4.21. (2-Trimethylsilyl)ethyl 2,3,4,6-tetra-O-benzyl-
galactopyranosyl-(1?6)-3,4-di-O-acetyl-2-O-(2-
a-D-
naphthyl)methyl-
-fucopyranosyl-(1?2)-3,4,6-tri-O-benzyl-b-
galactopyranosyl-(1?3)-4,6-O-benzylidene-2-deoxy-2-
phthalimido-b- -glucopyranoside 27
a-D-galactopyranosyl-(1?4)-2,3-di-O-benzyl-
a-L
D-
foam (0.319 g, 43%); Rf = 0.65 (DCM–acetone 97:3); [a]D = +64.8 (c
0.13); 1H NMR (500 MHz) d (ppm) 7.79 (m, 1H, arom.), 7.64 (m,
3H, arom.), 7.58 (d, 2H, J = 7.5 Hz, arom.), 7.46 (m, 2H, arom.), 7.36
(m, 11H, arom.), 7.31–6.97 (m, 41H, arom.), 6.79 (t, 1H, J = 7.4 Hz,
arom.), 5.72 (br s, 1H), 5.58 (s, 1H, Hacetalic), 5.49 (br s, 1H), 5.23–
5.17 (m, 2H), 5.11–5.06 (m, 2H), 4.94 (d, 1H, Jgem = 13.8 Hz, CHH),
4.86 (d, 1H, Jgem = 11.3 Hz, CHH), 4.81–4.68 (m, 7H), 4.65 (br s, 1H),
4.60–4.39 (m, 9H), 4.38–4.18 (m, 9H), 4.11 (t, 1H, J = 6.3 Hz) 4.03
(dd, 1H, JA = 10.5 Hz, JB = 2.1 Hz), 4.00 (br s, 1H), 3.98–3.89 (m, 3H),
3.86 (m, 1H), 3.82–3.76 (m, 2H), 3.74–3.70 (m, 2H), 3.69–3.63 (m,
4H), 3.62–3.56 (m, 2H), 3.51 (m, 1H), 3.46–3.41 (m, 2H), 3.27 (t,
1H, J = 8.7 Hz), 1.94 (s, 3H, COCH3), 1.76 (s, 3H, COCH3), 1.19 (d, 3H,
D
Compound 24 (0.521 g, 0.511 mmol) was reacted with 16
(0.428 g, 0.340 mmol) according to general method C at ꢀ8 °C. Puri-
fication of the crude product by column chromatography ((1) DCM–
acetone 98.5:1.5; (2) n-hexane–ethyl acetate 65:35) afforded 27 as a
foam (0.370 g, 50%); Rf = 0.78 (DCM–acetone 97:3); [
a
]
D = ꢀ4.3 (c
0.14); 1H NMR (500 MHz) d (ppm) 7.70 (m, 1H, arom.), 7.58–7.48
(m, 5H, arom.), 7.41–6.95 (m, 51H, arom.), 6.79 (d, 2H, J = 7.2 Hz),
5.82 (d, 1H, J = 3.82 Hz), 5.59 (d, 1H, J = 2.6 Hz), 5.55 (s, 1H, Hacetalic),
5.47 (dd, 1H, JA = 10.7 Hz, JB = 3.1 Hz), 5.23 (d, 1H, J = 3.1 Hz), 5.15 (d,
1H, J = 8.5 Hz), 5.01 (t, 1H, J = 9.5 Hz), 4.91 (d, 1H, J = 11.4 Hz), 4.85–
4.76 (m, 4H), 4.74–4.65 (m, 4H), 4.64–4.52 (m, 4H), 4.51–4.39 (m,
7H), 4.37–4.25 (m, 5H), 4.15 (s, 1H), 4.11–3.97 (m, 6H), 3.94 (dd,
1H, JA = 10.1 Hz, JB = 2.5 Hz), 3.86 (m, 1H), 3.83–3.74 (m, 5H), 3.73–
3.52 (m, 9H), 3.44 (m, 1H), 3.41–3.35 (m, 2H), 2.02 (s, 3H, COCH3),
J5 ,6 = 6.5 Hz, H-600), 0.68 (m, 2H, CH2Si), ꢀ0.16 (s, 9H, Si(CH3)3). 13C
00 00
NMR d (ppm) 169.98, 169.85 (C@O), 139.39, 139.17, 139.11,
139.07, 138.63, 138.48, 138.12, 137.97, 137.44, 135.57, 133.02,
132.71, 131.48 (Cq), 133.97, 128.45–127.38, 127.13, 127.05,
126.97, 126.47, 126.03, 126.00, 125.94, 125.72, 125.52, 125.15,
123.37 (Carom.), 100.50 (Cacetalic), 99.98, 98.58, 98.51, 97.36, 96.90
(anomer Cs), 82.57, 80.13, 79.14, 77.76, 75.93, 75.72, 73.23, 73.00,
70.96, 69.58, 69.43, 69.00, 67.67, 66.65, 66.14 (skeleton Cs), 75.33,
74.60, 73.98, 73.37, 73.03, 72.84, 72.60, 70.98, 70.81, 69.61, 68.82,
68.53, 67.31, 65.78 (OCH2), 56.70 (C-2), 20.77, 20.46 (COCH3),
17.95 (CH2Si), 16.65 (C-600), –1.66 (Si(CH3)3). Anal. Calcd for
C128H137NO28Si (2165.53): C, 70.99; H, 6.38. Found: C, 71.15; H,
6.35. MALDI-TOF: m/z calcd for [M+Na]+: 2186.899. Found:
2186.637.
1.92 (s, 3H, COCH3), 1.36 (d, 3H, J5 ,6 = 6.5 Hz, H-600), 0.77–0.63 (m,
00 00
2H, CH2Si), –0.16 (s, 9H, Si(CH3)3). 13C NMR d (ppm) 169.98, 169.70
(C@O), 138.86, 138.68, 138.61, 138.58, 138.51, 138.19, 137.88,
137.49, 135.86, 132.93, 132.61 (Cq), 128.48–127.90, 127.71–
127.39, 127.25, 127.13, 126.91, 126.82, 126.71, 126.19, 126.11,
125.78, 125.55, 125.45, 125.33 (Carom.), 100.69 (Cacetalic), 100.32,
99.31, 98.43, 97.45, 96.64 (anomer Cs), 83.04, 80.12, 79.40, 78.74,
76.67, 76.46, 75.81, 75.14, 74.98, 72.92, 72.87, 72.50, 72.40, 69.80,
69.16, 66.83, 66.61, 66.52 (skeleton Cs), 74.75, 74.22, 73.59, 73.50,
73.32, 73.13, 73.09, 72.18, 71.43, 71.14, 68.68, 68.48, 67.49, 67.25
(OCH2), 56.48 (C-2), 20.82, 20.61 (COCH3), 17.88 (CH2Si), 17.54 (C-
600), –1.67 (Si(CH3)3). Anal. Calcd for C128H137NO28Si (2165.53): C,
70.99; H, 6.38. Found: C, 71.20; H, 6.34. MALDI-TOF: m/z calcd for
[M+Na]+: 2186.899. Found 2186.666.
4.20. (2-Trimethylsilyl)ethyl 2,3,4,6-tetra-O-benzyl-
a-D-
galactopyranosyl-(1?6)-3,4-di-O-acetyl-2-O-(2-
naphthyl)methyl-
-fucopyranosyl-(1?2)-3,4,6-tri-O-benzyl-b-
galactopyranosyl-(1?3)-4,6-O-benzylidene-2-deoxy-2-
phthalimido-b- -glucopyranoside 26
a-D-galactopyranosyl-(1?3)-2,4-di-O-benzyl-
a-
L
D-
D
4.22. (2-Trimethylsilyl)ethyl 2,3,4,6-tetra-O-benzyl-
galactopyranosyl-(1?6)-2-O-(2-naphthyl)methyl-
galactopyranosyl-(1?2)-3,4-di-O-benzyl-
(1?2)-3,4,6-tri-O-benzyl-b- -galactopyranosyl-(1?3)-2-
acetamido-4,6-O-benzylidene-2-deoxy-b- -glucopyranoside 28
a
-D-
a-D
-
Compound24(0.520 g,0.510 mmol)wasreactedwith13(0.428 g,
0.340 mmol) according to general method C at ꢀ8 °C. Purification of
the crude product by column chromatography (DCM–acetone
98.5:1.5) afforded 26 as a foam (0.369 g, 50%); Rf = 0.70 (DCM–ace-
a-L-fucopyranosyl-
D
D
tone 98:2); [
a
]
D = ꢀ23.6 (c 0.12, CHCl3); 1H NMR1H NMR (500 MHz)
Compound 25 (0.280 g, 0.129 mmol) was converted to the title
compound in three steps according to general method D. Dephtha-
loylation step: TLC (DCM–MeOH 99:1), Rf,free amine = 0.32. Acetylation
step: white crystals (0.236 g, 88%); Rf = 0.53 (n-hexane–ethyl ace-
tate 55:45); mp 166–168 °C (ethyl acetate–n-hexane);
d (ppm) 7.81 (m, 1H, arom.), 7.72–7.59 (m, 3H, arom.), 7.52–7.38
(m, 12H, arom.), 7.34–7.11 (m, 42H, arom.), 7.10–7.05 (m, 3H, arom.),
7.03–6.97 (m, 3H, arom.), 5.50–5.43(m, 3H), 5.35–5.29 (m, 2H), 5.04–
4.91(m,3H),4.85–4.76(m,5H),4.70–4.61(m, 4H),4.57–4.49(m, 4H),
4.45–4.41 (m, 2H), 4.35–4.21 (m, 9H), 4.17 (d, 1H, J = 6.5 Hz), 4.09–
4.02 (m, 2H), 4.01–3.90 (m, 5H), 3.86–3.78 (m, 2H), 3.77–3.67 (m,
[a]D = +36.0 (c 0.38, CHCl3); C122H137NO27Si (2077.47). O-Deacety-
lation step: crude product was purified by column chromatography
4H), 3.63 (t, 1H, J = 10.3 Hz), 3.59–3.41 (m, 8H), 3.33 (dd, 1H, JA
=
(DCM–acetone 91:9), Rf = 0.34 to give 28 as a foam (0.211 g, 82%
9.5 Hz, JB = 2.3 Hz), 3.26 (m, 1H), 1.94 (s, 3H, COCH3), 1.87 (s, 3H,
over three steps); [a]
D = + 6.8 (c 0.13, CHCl3); 1H NMR (200 MHz)
COCH3), 1.36 (d, 3H, J5 ,6 = 6.3 Hz, H-600), 0.73 (m, 1H, CHHSi), 0.64
d (ppm) 7.70–7.05 (m, 62H, arom.), 6.59 (d, 1H, J = 7.2 Hz), 5.58
(s, 1H), 5.42 (s, 2H), 5.12–3.30 (m, 59H), 2.05 (s, 2H), 1.89 (s, 3H),
1.32–1.16 (m, 5H), 0.96–0.80 (m, 2H CH2Si), ꢀ0.07 (s, 9H, Si(CH3)3).
13C NMR d (ppm) 170.41 (COCH3), 138.71, 138.65, 138.50, 138.39,
138.18, 138.14, 137.72, 137.43, 135.56, 132.94, 132.65 (Cq),
00 00
(m, 1H, CHHSi), ꢀ0.18 (s, 9H, Si(CH3)3). 13C NMR d (ppm) 169.94,
169.52 (C@O), 139.41, 138.70, 138.69, 138.63, 138.56, 138.32,
138.25, 138.06, 137.74, 137.53, 135.74, 133.07, 132.69 (Cq), 132.18,
129.79, 129.24, 128.64, 128.29–127.90, 127.69–127.29, 126.97,
126.93, 126.60, 126.05, 125.93, 125.66, 125.43, 125.03 (Carom.),
100.88 (Cacetalic), 101.11, 98.75, 98.14, 97.91, 96.62 (anomer Cs),
82.29, 81.16, 80.71, 79.10, 76.31, 76.13, 75.49, 74.95, 74.47, 73.02,
72.56, 69.68, 68.92, 68.78, 67.36, 66.42 (skeleton Cs), 75.69, 74.68,
128.53–127.11, 126.58, 126.37, 125.98, 125.61, 125.48 (Carom.
)
101.81, 100.73, 98.44, 98.24 (Cacetalic, anomer Cs), 82.19, 80.05,
79.27, 78.84, 76.84, 76.23, 75.68, 74.73, 72.83, 70.75, 69.72,
69.27, 68.64, 67.12, 66.14 (skeleton Cs), 74.67, 74.53, 74.27,

Z. B. Szabó et al. / Tetrahedron: Asymmetry 20 (2009) 808–820
819
73.28, 73.18, 72.93, 72.57, 72.33, 71.98, 71.47, 68.47, 68.33, 67.88,
C, 70.86; H, 6.69. MALDI-TOF: m/z calcd for [M+Na]+: 2014.883.
66.91 (OCH2), 57.23 (C-2), 23.15 (COCH3), 18.04 (CH2Si), 16.75 (C-
6
Found 2014.716.
0000), –1.66 (Si(CH3)3). Anal. Calcd for C118H133NO25Si (1993.40): C,
71.10; H, 6.73. Found: C, 71.36; H, 6.70. MALDI-TOF: m/z calcd
4.25. (2-Trimethylsilyl)ethyl
a-D-galactopyranosyl-(1?6)-a-D-
for [M+Na]+: 2014.883. Found 2014.719.
galactopyranosyl-(1?2)- -fucopyranosyl-(1?2)-b-D-
a
-L
galactopyranosyl-(1?3)-2-acetamido-2-deoxy-b-D-
4.23. (2-Trimethylsilyl)ethyl 2,3,4,6-tetra-O-benzyl-
galactopyranosyl-(1?6)-2-O-(2-naphthyl)methyl-
galactopyranosyl-(1?3)-2,4-di-O-benzyl-
(1?2)-3,4,6-tri-O-benzyl-b- -galactopyranosyl-(1?3)-2-
acetamido-4,6-O-benzylidene-2-deoxy-b- -glucopyranoside 29
a
-
D
-
glucopyranoside 1
a
-D-
a
-L
-fucopyranosyl-
Compound 28 (0.185 g, 0.092 mmol) was converted to the title
compound according to general method E. The yield after column
chromatography (DCM–MeOH–H2O 5:5:0.5): White powder
D
D
(0.080 g, 90%); Rf = 0.46 (DCM–MeOH–H2O 6:4:0.8); [a]D = +29.7
Compound 26 (0.230 g, 0.106 mmol) was converted to the title
compound in three steps according to general method D. Dephtha-
loylation step: TLC (DCM–MeOH 99:1), Rf,free amine = 0.50. Acetylation
step: product was obtained as a foam (0.199 g, 90%); Rf = 0.42 (n-
(c 0.14, MeOH). 1H NMR (500 MHz, D2O) d (ppm) 4.32–4.25 (d,
2H), 3.92–3.80 (m, 6H), 3.80–3.54 (m, 17H), 3.54–3.45 (m, 4H),
00 00
3.37–3.30 (m, 2H), 1.92 (s, 3H, CH3CO), 1.09 (d, 3H, J5 ,6 = 6.5 Hz,
CH3), 0.81, 0.70 (2 Â ddd, 2H, CH2Si), –0.15 (s, 9H, Si(CH3)3). 13C
NMR d (ppm) 174.07 (C@O), 77.48, 76.83, 75.72, 75.17, 73.89,
72.56, 72.45, 71.34, 69.73, 69.65, 69.55, 69.36, 69.12, 68.81,
68.58, 67.17 (skeleton Cs), 54.94 (C-2), 68.63 (C-6000), 67.51
(OCH2CH2Si), 61.51, 61.44, 60.99 (3 Â C-6), 22.72 (CH3CO), 17.53
(CH2Si), 15.57 (C-600), ꢀ2.08 (Si(CH3)3). Anal. Calcd for C37H67NO25Si
(954.01): C, 46.58; H, 7.08. Found: C, 46.37; H, 7.12. MALDI-TOF:
m/z calcd for [M+Na]+: 976.366. Found 976.363.
hexane–ethyl acetate 6:4); [
a
]
D = ꢀ11.5 (c 0.15, CHCl3); MALDI-
TOF: m/z calcd for [M+Na]+: 2098.904. Found 2097.698. O-Deacet-
ylation step: crude product was purified by column chromatogra-
phy (n-hexane–ethyl actetate, 1:1, Rf = 0.34) to give 29 as a foam
(0.165 g, 78% over three steps); Rf = 0.68 (DCM–acetone 94:6);
[a]
D = +5.8 (c 0.12, CHCl3); 1H NMR1H NMR (200 MHz) d (ppm)
7.85–7.05 (m, 67H, arom.), 6.48 (d, 1H, J = 6.8 Hz), 5.58–5.40 (m,
3H), 5.10–3.30 (m, 63H), 2.43 (br s, 1H), 1.82 (s, 3H COCH3), 1.35
(d, 3H, J5 ,6 = 6.0 Hz, H-600), 1.28 (s, 1H), 1.04–0.85 (m, 2H, CH2Si),
4.26. (2-Trimethylsilyl)ethyl
a-D-galactopyranosyl-(1?6)-a-D-
00 00
0.00 (s, 9H, Si(CH3)3). 13C NMR d (ppm) 170.41 (COCH3), 138.57,
138.49,138.37, 138.04, 137.84, 137.79, 137.49, 135.67, 133.06,
132.77 (Cq), 128.69, 128.31–127.62, 127.49, 127.46, 127.24,
126.89, 126.08, 126.01, 125.80, 125.58, 125.38 (Carom.), 102.31,
100.93, 99.18, 97.67, 97.12 (Cacetalic, anomer Cs), 82.46, 80.34,
80.11, 78.84, 78.25, 76.95, 76.83, 76.16, 75.46, 74.62, 74.48,
72.64, 69.76, 68.92, 68.86, 68.59, 67.76, 66.47 (skeleton Cs),
75.02, 74.67, 74.42, 73.60, 73.44, 73.32, 72.80, 72.58, 71.79,
71.22, 68.71, 68.41, 66.81 (OCH2), 56.67 (C-2), 23.11 (COCH3),
17.92 (CH2Si), 16.90 (C-600), ꢀ1.53 (Si(CH3)3); Anal. Calcd (%) for
C118H133NO25Si (1993.40): C, 71.10; H, 6.73. Found: C, 70.89; H,
6.78. MALDI-TOF: m/z calcd for [M+Na]+: 2014.883. Found
2014.717.
galactopyranosyl-(1?3)- -fucopyranosyl-(1?2)-b-D-
galactopyranosyl-(1?3)-2-acetamido-2-deoxy-b-D-
glucopyranoside 2
a
-
L
Compound 29 (0.135 g, 0.067 mmol) was converted to the title
compound according to general method E. The yield after column
chromatography (DCM–MeOH–H2O 4:6:0.8): White powder
(0.055 g, 85%); Rf = 0.39 (DCM–MeOH–H2O 4:6:0.5); [a]D = +21.1
(c 0.18, MeOH). 1H NMR (500 MHz, D2O) d (ppm) 4.26–4.20 (m,
2H), 3.94 (br s, 1H), 3.91 (br s, 1H), 3.88–3.72 (m, 10H), 3.72–
3.57 (m, 10H), 3.55–3.48 (m, 3H), 3.45 (t, 1H), 3.37–3.30 (m, 2H),
00 00
1.90 (s, 3H, COCH3), 1.09 (d, 3H, J5 ,6 = 6.5 Hz, CH3), 0.83 (ddd,
1H, CHHSi), 0.76–0.66 (m, 1H, CHHSi), ꢀ0.14 (s, 9H, Si(CH3)3); 13C
NMR d (ppm) 173.42 (COCH3), 80.32, 77.39, 77.16, 75.85, 75.35,
73.68, 71.77, 71.29, 70.12, 69.83, 69.58, 69.50, 69.44, 69.09,
68.99, 68.45, 67.13, 66.69 (skeleton Cs), 68.76 (C-6000), 67.65
(OCH2CH2Si), 61.73, 61.50, 61.05 (3 Â C-6), 55.04 (C-2), 22.85
(COCH3), 17.67 (CH2Si), 15.93 (C-600), ꢀ2.08 (Si(CH3)3). Anal. Calcd
for C37H67NO25Si (954.01): C, 46.58; H, 7.08. Found: C, 46.40; H,
7.05. MALDI-TOF: m/z calcd for [M+Na]+: 976.366. Found 976.249.
4.24. (2-Trimethylsilyl)ethyl 2,3,4,6-tetra-O-benzyl-
galactopyranosyl-(1?6)-2-O-(2-naphthyl)methyl-
galactopyranosyl-(1?4)-2,3-di-O-benzyl-
(1?2)-3,4,6-tri-O-benzyl-b- -galactopyranosyl-(1?3)-2-
acetamido-4,6-O-benzylidene-2-deoxy-b- -glucopyranoside 30
a
-
D-
a
-D-
a-L-fucopyranosyl-
D
D
Compound 27 (0.330 g, 0.152 mmol) was converted to the title
compound according to general method D. Dephthaloylation step:
TLC (DCM–MeOH = 99:1), Rf,free amine = 0.50. Acetylation step: product
wasobtained asa foam(0.285 g, 90%);Rf =0.35(n-hexane–ethyl ace-
4.27. (2-Trimethylsilyl)ethyl
a-D-galactopyranosyl-(1?6)-a-D-
galactopyranosyl-(1?4)- -fucopyranosyl-(1?2)-b-D-
a
-L
galactopyranosyl-(1?3)-2-acetamido-2-deoxy-b-D-
tate 65:35); [
a
]
D = ꢀ12.8 (c 0.16). O-Deacetylation step: crude prod-
glucopyranoside 3
uct was purified by column chromatography (DCM–acetone 9:1)
to give 30 as a foam (0.249 g, 82% over three steps); Rf = 0.58
Compound 30 (0.220 g, 0.110 mmol) was converted to the title
compound according to general method E. The yield after column
chromatography (DCM–MeOH–H2O 5:5:0.5): White powder
(DCM–acetone 91:9); [a]
D = +5.8 (c 0.12); 1H NMR (200 MHz) d
(ppm) 7.73–6.82 (m, 62H, arom.), 6.53 (d, 1H, J = 7.0 Hz), 5.88 (s,
1H), 5.50 (s, 2H), 5.05–3.30 (m, 58H), 2.65 (s, 1H), 1.84 (s, 3H, COCH3),
1.36–1.24(m, 4H), 0.98–0.82(m, 2H, CH2Si), 0.00 (Si(CH3)3). 13CNMR
d (ppm) 170.39 (COCH3), 138.46, 138.39, 138.11, 138.05, 138.01,
137.76, 137.67, 137.34, 135.74, 132.95, 132.55 (Cq), 128.22–
127.64, 127.52, 127.50, 127.43, 127.29, 127.17, 127.03, 126.78,
126.00, 125.75, 125.36, 125.11, 124.73 (Carom.), 101.97, 100.77,
100.56, 98.56, 97.16, 95.96 (Cacetalic, anomer Cs), 82.86, 79.55,
78.64, 76.85, 76.65, 76.11, 75.64, 74.74, 73.71, 72.92, 69.50, 69.12,
68.37, 67.02, 66.12 (skeleton Cs), 74.56, 74.25, 73.55, 73.28, 73.10,
72.80, 72.57, 72.23, 70.86, 68.67, 68.52, 67.76, 66.85 (OCH2), 57.54
(C-2), 23.17 (COCH3), 18.02 (CH2Si), 17.76 (C-60000), ꢀ1.63 (Si(CH3)3).
Anal. Calcd for C118H133NO25Si (1993.40): C, 71.10; H, 6.73. Found:
(0.095 g, 90%); Rf = 0.39 (DCM–MeOH–H2O 5:5:0.5); [a]D = +22.6 (c
0.22, MeOH). 1H NMR (500 MHz, D2O) d (ppm) 4.25–4.18 (m, 2H),
3.92 (d, 1H), 3.89–3.56 (m, 22H), 3.56–3.42 (m, 4H), 3.37–3.30 (m,
00 00
2H), 1.89 (s, 3H, COCH3), 1.17 (d, 3H, J5 ,6 = 6.6 Hz, CH3), 0.85–0.78
(m, 1H, CHHSi), 0.74–0.67 (m, 1H, CHHSi), ꢀ0.14 (s, 9H, Si(CH3)3).
13C NMR d (ppm) 173.84 (COCH3), 83.36, 77.63, 76.85, 75.77,
75.36, 73.72, 71.34, 70.50, 70.34, 69.72, 69.66, 69.55, 69.46, 69.44,
69.05, 69.01, 68.51, 66.63 (skeleton Cs), 68.53 (C-6000), 67.56
(OCH2CH2Si), 61.46, 60.95 (3 Â C-6), 54.93 (C-2), 22.59 (COCH3),
17.49 (CH2Si), 16.29 (C-600), –2.06 (Si(CH3)3). Anal. Calcd for
C37H67NO25Si (954.01): C, 46.58; H, 7.08. Found: C, 46.75; H, 7.11.
MALDI-TOF: m/z calcd for [M+Na]+: 976.366. Found 976.424.

820
Z. B. Szabó et al. / Tetrahedron: Asymmetry 20 (2009) 808–820
6. Szabó, Z. B.; Borbás, A.; Bajza, I.; Lipták, A. Tetrahedron: Asymmetry 2005, 16,
Acknowledgement
83–95.
7. Jain, R. K.; Sarkar, A. K.; Matta, K. L. Carbohydr. Res. 1991, 220, C1–C4.
8. Martín-Lomas, M.; Flores-Mosquera, M.; Chiara, J. L. Eur. J. Org. Chem. 2000,
1547–1562.
9. Matta, K. L.; Rana, S. S.; Piskorz, C. F.; Abbas, S. A. Carbohydr. Res. 1984, 131,
247–255.
This work was supported by the Hungarian Research Fund
(OTKA NK 48798 to A.L. and K 62802 to A.B.)
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