A facile regio- and stereoselective synthesis of mannose octasaccharide of the N-glycan in human CD2 and mannose hexasaccharide antigenic factor 13b

Article abstract of DOI:10.1016/S0008-6215(01)00307-X

A highly concise and effective synthesis of the mannose octasaccharide of the N-linked glycan in the adhesion domain of human CD2 was achieved via TMSOTf-promoted selective 6-glycosylation of a trisaccharide 4,6-diol acceptor with a pentasaccharide donor, followed by deprotection. The pentasaccharide was constructed by selective 3,6-diglycosylation of 1,2-O-ethylidene-β-D-mannopyranose with 2-O-acetyl-3,4,6-tri-O-benzoyl-α-D-mannopyranosyl-(1 → 2)-3,4,6-tri-O-benzoyl-α-D-mannopyranosyl trichloroacetimidate, while the trisaccharide was obtained by selective 3-O-glycosylation of allyl 4,6-O-benzylidene-α-D-mannopyranoside with the same disaccharide trichloroacetimidate, followed by debenzylidenation. The mannose hexasaccharide antigenic factor 13b was synthesized by condensation of a trisaccharide donor, 2-O-acetyl-3,4,6-tri-O-benzoyl-α-D-mannopyranosyl-(1 → 2)-3,4,6-tri-O-benzoyl-α-D-mannopyranosyl-(1 → 3)-4,6-di-O-acetyl-2-O-benzoyl-α-D-mannopyranosyl trichloroacetimidate, with a trisaccharide acceptor, methyl 3,4,6-tri-O-benzoyl-α-D-mannopyranosyl-(1 → 2)-3,4,6-tri-O-benzoyl-α-D-mannopyranosyl-(1 → 2)-3,4,6-tri-O-benzoyl-α-D-mannopyranoside, followed by deprotection.

Full text of DOI:10.1016/S0008-6215(01)00307-X

Carbohydrate Research 337 (2002) 207–215
www.elsevier.com/locate/carres
A facile regio- and stereoselective synthesis of mannose
octasaccharide of the N-glycan in human CD2 and mannose
hexasaccharide antigenic factor 13b
Yuliang Zhu, Langqiu Chen, Fanzuo Kong*
Research Center for Eco-En6ironmental Sciences, Academia Sinica, PO Box 2871, Beijing 100085, China
Received 5 September 2001; accepted 14 November 2001
Abstract
A highly concise and effective synthesis of the mannose octasaccharide of the N-linked glycan in the adhesion domain of human
CD2 was achieved via TMSOTf-promoted selective 6-glycosylation of a trisaccharide 4,6-diol acceptor with a pentasaccharide
donor, followed by deprotection. The pentasaccharide was constructed by selective 3,6-diglycosylation of 1,2-O-ethylidene-b-
mannopyranose with 2-O-acetyl-3,4,6-tri-O-benzoyl-a- -mannopyranosyl-(1“2)-3,4,6-tri-O-benzoyl-a- -mannopyranosyl
trichloroacetimidate, while the trisaccharide was obtained by selective 3-O-glycosylation of allyl 4,6-O-benzylidene-a- -mannopy-
ranoside with the same disaccharide trichloroacetimidate, followed by debenzylidenation. The mannose hexasaccharide antigenic
factor 13b was synthesized by condensation of a trisaccharide donor, 2-O-acetyl-3,4,6-tri-O-benzoyl-a- -mannopyranosyl-(1“2)-
3,4,6-tri-O-benzoyl-a- -mannopyranosyl-(1“3)-4,6-di-O-acetyl-2-O-benzoyl-a- -mannopyranosyl trichloroacetimidate, with a
trisaccharide acceptor, methyl 3,4,6-tri-O-benzoyl-a- -mannopyranosyl-(1“2)-3,4,6-tri-O-benzoyl-a- -mannopyranosyl-(1“2)-
3,4,6-tri-O-benzoyl-a- -mannopyranoside, followed by deprotection. © 2002 Elsevier Science Ltd. All rights reserved.
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Keywords: Mannose oligosaccharides; Trichloroacetimidates; Regio- and stereoselective synthesis
1. Introduction
the high mannose N-glycan at Asn65 could be normally
expressed on cell surfaces, but showed neither antibody-
nor ligand-binding activity. These data suggest that the
N-linked adhesion domain glycan on human CD2 plays
an important role in maintaining native receptor struc-
ture. Wagner and co-workers investigated the solution
structure of a fragment containing the high mannose
N-glycan by NMR spectrometry.2 Bewley and Otero-
Quintero reported the important binding of anti-HIV
protein cyanovirin-N to high mannose oligosaccharides
very recently.5 For a study of the details of the recogni-
tion mechanism, chemically synthesized oligosaccha-
rides are required because such homogeneous
oligosaccharide samples are hardly obtainable from
natural sources. We present herein a facile and conver-
gent synthesis of the mannose octasaccharide of the
N-glycan in the adhesion domain of human CD2.
Meanwhile we also describe an efficient synthesis of
mannose hexasaccharide antigenic factor 13b6 using a
similar strategy and the same synthons.
Human CD2, a cell-surface glycoprotein on T
lymphocytes and natural killer cells, is important in
mediating both cellular adhesion and signal transduc-
tion through interactions with its counterreceptor,
CD58.1 The adhesion domain of CD2 bears a single
N-linked carbohydrate containing mannose oligosac-
charides.2 Recny et al. indicated that glycosylation is
required for human CD2 adhesion function.3 More-
over, transmembrane CD2 variants with mutations in
the consensus N-glycosylation sequence Asn65–Gly66–
Thr67 (N65Q3 or T67A4) that preclude attachment of
* Corresponding author. Tel.: +86-10-62936613; fax: 86-
10-62923563.
E-mail address: fzkong@mail.rcees.ac.cn (F. Kong).
0008-6215/02/$ - see front matter © 2002 Elsevier Science Ltd. All rights reserved.
PII: S0008-6215(01)00307-X

208
Y. Zhu et al. / Carbohydrate Research 337 (2002) 207–215
sation of 3 promoted by catalytic TMSOTf gave the
2. Results and discussion
disaccharide 4 in satisfactory yield (66%). Deallylation
with PdCl2, followed by activation with CCl3CN in the
presence of DBU or K2CO3, produced the disaccharide
donor 5. Regioselective coupling of 5 with allyl 4,6-O-
Scheme 1 shows the structure of the high-mannose
N-glycan of human CD2105 containing the D1 D2
isomer of Man-8 as marked with a bracket. Retrosyn-
thetic analysis indicated that the mannose octamer can
be obtained by condensation of two moieties, i.e., a
mannose pentamer donor and a mannose trimer accep-
tor. The pentasaccharide then can be constructed from
a disaccharide donor and a 1,2-ethylidenated mannose
acceptor, while the trisaccharide can be built from the
same disaccharide donor and another simple mannose
derivative.
benzylidene-a-
-mannopyranoside (6)12 resulted in the
D
(1“3)-linked trisaccharide 7, and subsequent acetyla-
1
tion yielded the trisaccharide 8. The H NMR spectrum
of 8 showed H-2 of the reducing mannose at l 5.42
ppm with J1,2 1.4 and J2,3 2.8 Hz, indicating the 3-selec-
tive glycosylation of 6. Debenzylidenation of 8 gave the
trisaccharide acceptor 9. For the pentasaccharide donor
synthesis, 1,2-O-ethylidene-b- -mannopyranose (10)
D
We previously reported a highly regio- and stereose-
lective method7 through orthoester formation–rear-
rangement for the synthesis of oligosaccharides, and
some biologically important oligosaccarides such as the
phytoalexin elicitor hexasaccharide were efficiently syn-
thesized.8 Later on we found that by controlling the
reaction conditions, (1“6)-linked oligosaccharides
with 1,2-trans linkages were readily constructed with
acylated glycosyl trichloroimidates as the donors and
unprotected or partially protected saccharides as the
acceptors through orthoester intermediates.9 We also
found that (1“2)-linked mannosyl disaccharides were
easily synthesized by self-condensation of benzoylated
mannose 1,2-orthoester.10 Based on these new findings,
we designed a concise and effective route for the syn-
thesis of the mannosyl octasaccharide as shown in
Scheme 2.
was chosen as the starting material since its glycosyla-
tion has excellent regioselectivity for both the 6- and
3-positions via orthoester intermediates,7b and its ethyl-
idene group is readily removed for the next reaction.
Thus, coupling of
5
(2.2 equiv) with 10 in
dichloromethane in the presence of catalytic TMSOTf
produced the pentasaccharide 11. It was noted that
addition of TMSOTf was performed at −20 °C to
ensure that at the initial stage of the reaction, the
orthoester was formed with high regioselectivity,7b,9 and
then it rearranged to the required pentasaccharide
along with extension of the reaction time. If TMSOTf
was added at room temperature, the reaction was very
fast, and the 3,4,6-trisubstituted heptasaccharide was
the major product, even if only 2 equiv of 5 were used.
Acetylation of 11 gave fully protected pentasaccharide
1
12, and its H NMR spectrum showed a newly emerged
Orthoester 3 was obtained from acetylated mannosyl
bromide 1 through the intermediate 2 in high yield
(90%) by a previously reported method.11 Self-conden-
triplet at l 5.20 ppm with J3,4=J4,5 10 Hz for H-4
confirming the 3,6-glycosylation of 10. Removal of the
ethylidene group of 12 with 90% trifluoroacetic acid,
followed by acetylation with acetic anhydride in pyri-
dine, selective 1-O-deacetylation with (NH4)2CO3 and
subsequent activation with CCl3CN in the presence of
DBU or K2CO3 afforded the pentasaccharide donor 14.
Selective 6-O-glycosylation of 99,13 with 14 produced
the octasaccharide 15 as the major product. Acetylation
of 15 gave the fully acylated octasaccharide 16, and the
structures of 15 and 16 were characterized by mass
spectrometry, which showed m/z 3479 [M+] and 3521
[M+], respectively. The 13C NMR spectrum of 16 gave
eight signals for C-1 from l 96.0–99.7 ppm, with
2JC-1ꢀH-1 170–174 Hz, indicating all a linkages. Deac-
ylation was conducted at room temperature in ammo-
nia-saturated methanol for one week giving the target
mannose octasaccharide 17, whose bioassay is in
process.
The synthesis of mannose hexasaccharide antigenic
factor 13b was accomplished using a similar strategy
and the same synthons, as shown in Scheme 3. Thus,
coupling of 2-O-acetyl-3,4,6-tri-O-benzoyl-a-
D-manno-
Scheme 1.
pyranosyl trichloroacetimidate (18)10 with methyl 3,4,6-

Y. Zhu et al. / Carbohydrate Research 337 (2002) 207–215
209
,
,
Scheme 2. Reagents: (a) lutidine, CH2Cl2, 4 A MS, then MeONa, MeOH; (b) BzCl–pyridine (dry); (c) TMSOTf, CH2Cl2, 4 A MS;
(d) PdCl2, CH2Cl2; (e) CCl3CN, DBU, CH2Cl2; (f) Ac2O–pyridine (dry); (g) 99.9:0.1 CH3OH–CH3COCl; (h) 90% CF3COOH; (i)
DMF, (NH4)2CO3; (j) NH3–MeOH.
tri-O-benzoyl-a-
D
-mannopyranosyl-(1“2)-3,4,6-tri-O-
3. Experimental
benzoyl-a-
D
-mannopyranoside (19)10 gave the trisac-
charide 20, and subsequent deacetylation afforded the
trisaccharide acceptor 21.10 The trisaccharide donor 26
was obtained from 7 through benzoylation (“22),
debenzylidenation (“23), acetylation (“24), deallyla-
tion (“25), and trichloroacetimidation. Condensation
of 26 with 21 yielded the hexasaccharide 27, and its
deacylation gave the antigenic factor 13b.
In summary, we present herein a very effective regio-
and stereoselective synthesis of the mannose octasac-
charide of the N-glycan in human CD2 and the man-
nose hexasaccharide antigenic factor 13b. Pre-
paration on large scale is possible owing to the rela-
tively simple procedure and convenient raw materials.
The method described will be suitable for the prepara-
tion of higher mannose oligosaccharides with similar
structure.
General methods.—Optical rotations were deter-
mined at 25 °C with a Perkin–Elmer model 241-MC
automatic polarimeter. Melting points were determined
1
with a ‘Mel-Temp’ apparatus. H NMR, 13C NMR and
1H–1H COSY and 1H–13C COSY spectra were
recorded with Bruker ARX 400 spectrometers (400
MHz for 1H, 100 MHz for 13C) at 25 °C for solutions in
CDCl3 or D2O as indicated. Chemical shifts are given
in ppm downfield from internal Me4Si. Mass spectra
were measured using MALDI-TOF-MS with CCA as
matrix or recorded with a VG PLATFORM mass
spectrometer using the ESI mode. IR spectra were
recorded with a Hitachi 270-30 spectrometer. Thin-
layer chromatography (TLC) was performed on Silica
Gel HF254 with detection by charring with 30% (v/v)
H2SO4 in MeOH or in some cases by a UV lamp.

210
Y. Zhu et al. / Carbohydrate Research 337 (2002) 207–215
,
Scheme 3. Reagents: (a) TMSOTf, CH2Cl2, 4 A MS; (b) 95:5 CH3OH–CH3COCl; (c) BzCl–pyridine (dry); (d) 99.9:0.1
CH3OH–CH3COCl; (e) Ac2O–pyridine (dry); (f) PdCl2, HOAc–NaOAc; (g) CCl3CN, DBU, CH2Cl2; (h) TMSOTf, CH2Cl2, 4 A
MS; (i) NH3–MeOH.
,
Column chromatography was conducted by elution of a
column (16×240 mm, 18×300 mm, 35×400 mm) of
silica gel (100–200 mesh) with EtOAc–petroleum ether
(60–90 °C) as the eluent. Solutions were concentrated
at B60 °C under reduced pressure.
PhꢀCH), 5.40 (dd, 1 H, CH2ꢁCHꢀCH2), 5.30 (dd, 1 H,
CH2ꢁCHꢀCH2), 5.02 (s, 1 H, H-1%%), 4.91 (s, 1 H), 4.90
(s, 1 H), (H-1, H-1%), 4.60–4.50 (m, 2 H), 4.47 (dd, J2,3
2.8, J1,2 1.3 Hz, 1 H, H-2), 4.36 (dd, J3,4 10.0 Hz, 1 H,
H-3), 4.29–4.17 (m, 3 H), 4.15–4.05 (m, 3 H), 4.02–
3.95 (m, 3 H), 3.88 (dd, 1 H, CH2ꢁCHꢀCH2), 3.82 (dd,
J4,5 10.0 Hz, 1 H, H-4), 2.01 (s, 3 H, CH3CO); 13C
NMR (CDCl3): l 169.29, (CH3CO), 166.48, 165.89,
165.69, 165.67, 165.45, 165.07, (4 C6H5CO), 101.92,
(PhꢀC), 99.95, 99.39, 98.87, (C-1I–III), 78.66, (C-3),
75.84, 73.32, 71.28, 70.51, 69.83, 69.46, 69.44, 68.91,
67.89, 66.85, 64.14, 63.40, 62.77, 55.01 (C-2,3,4,5,6I–III).
Anal. Calcd for C72H66O23: C, 66.56; H, 5.08. Found:
C, 66.68; H, 5.01.
Allyl 2-O-acetyl-3,4,6-tri-O-benzoyl-h-
ranosyl-(1“2)-3,4,6-tri-O-benzoyl-h- -mannopyran-
osyl-(1“3)-4,6-O-benzylidene-h- -mannopyranoside
D-mannopy-
D
D
(7).—The disaccharide donor 510 (1153 mg, 1 mmol)
and the monosaccharide acceptor 6 (308 mg, 1 mmol)
were dried together under high vacuum for 2 h, then
dissolved in anhyd CH2Cl2 (50 mL). TMSOTf (15 mL,
0.08 equiv) was added dropwise at −20 °C with N2
protection. The reaction mixture was stirred for 2 h,
during which time the reaction temperature was gradu-
ally raised to ambient temperature. Then the mixture
was neutralized with triethylamine and concentrated
under reduced pressure to an oily residue. Purification
by column chromatography (1:1.5 petroleum ether–
EtOAc) gave 7 (1194 mg, 92%) as colorless crystals: mp
135–137 °C; [h]D −2.0° (c 0.9, CHCl3); 1H NMR
(CDCl3): l 8.06–7.32 (m, 30 H, BzꢀH), 5.95–5.85 (m, 3
H, H-3%%, H-4%%, CH2ꢁCHꢀCH2), 5.83 (dd, J2,3 3.0, J3,4
10.0 Hz, 1 H, H-3%), 5.77 (dd, J4,5 10.1 Hz, 1 H, H-4%),
5.61 (dd, J2,3 3.0, J1,2 1.5 Hz, 1 H, H-2%), 5.56 (s, 1 H,
Allyl 2-O-acetyl-3,4,6-tri-O-benzoyl-h-
ranosyl-(1“2)-3,4,6-tri-O-benzoyl-h- -mannopyran-
osyl-(1“3)-2-O-acetyl-4,6-O-benzylidene-h- -manno-
D-mannopy-
D
D
pyranoside (8).—Acetic anhydride (1 mL, 10 mmol)
was added dropwise to a solution of 7 (1298 mg, 1
mmol) in pyridine (30 mL), and the mixture was stirred
overnight at rt. TLC (1.5:1 petroleum ether–EtOAc)
indicated that the reaction was complete. The mixture
was diluted with CH2Cl2, washed with 1 N HCl, water,
and satd aq NaHCO3. The organic layers were com-
bined, dried, and concentrated. Purification by column

Y. Zhu et al. / Carbohydrate Research 337 (2002) 207–215
211
chromatography (2:1 petroleum ether–EtOAc) quanti-
tatively gave 8 as colorless crystals: mp 130–132 °C;
[h]D −7.3° (c 0.9, CHCl3); H NMR (CDCl3): l 8.09–
tion. The reaction mixture was stirred for 3 h, during
which time the reaction temperature was gradually
raised to ambient temperature. Then the mixture was
neutralized with triethylamine and concentrated under
reduced pressure to give an oily residue. Purification by
column chromatography (1:1.5 petroleum ether–
EtOAc) gave 11 (940 mg, 86%) as a colorless solid: mp
141–144 °C; [h]D −11.5° (c 1.1, CHCl3); 1H NMR
(CDCl3): l 7.98–7.25 (m, 60 H, BzꢀH), 6.03–5.85 (m, 8
H), 5.67 (dd, J 3.0, J 1.7 Hz, 1 H), 5.64 (dd, J 3.1, J 1.7
Hz, 1 H), 5.53 (s, 1 H), 5.26 (q, 1 H, CH3ꢀCH), 5.20 (s,
1 H), 5.12 (d, J 1.6 Hz, 1 H), 5.08 (d, J 1.7 Hz, 1 H),
5.05 (d, J 1.7 Hz, 1 H), 4.60–4.46 (m, 13 H), 4.42 (dd,
J 3.0, J 1.7 Hz, 1 H), 4.20 (dd, J 3.0, J 1.7 Hz, 1 H),
4.04 (t, J 10.0 Hz, 1 H), 3.98–3.94 (m, 1 H), 3.83 (dd,
J 3.2, J 10.0 Hz, 1 H), 3.75–3.68 (m, 1 H), 3.41–3.37
(m, 1 H), 2.01 (s, 3 H, CH3CO), 2.00 (s, 3 H, CH3CO),
1.50 (d, 3 H, CH3ꢀCH). Anal. Calcd for C120H106O40:
C, 65.87; H, 4.85. Found: C, 65.98; H, 4.80.
1
7.35 (m, 30 H, BzꢀH), 5.97 (t, J3,4=J4,5 10.0 Hz, 1 H,
H-4%%), 5.93–5.85 (m, 2 H, H-3%%, CH2ꢁCHꢀCH2), 5.81
(dd, J2,3 3.0, J3,4 10.0 Hz, 1 H, H-3%), 5.72 (t, J4,5 10.1
Hz, 1 H, H-4%), 5.63 (dd, J2,3 3.0, J1,2 1.5 Hz, 1 H,
H-2%%), 5.55 (s, 1 H, PhꢀCH), 5.42 (dd, J2,3 2.8, J1,2 1.4
Hz, 1 H, H-2), 5.32 (dd, 1 H, CH2ꢁCHꢀCH2), 5.24 (dd,
1 H, CH2ꢁCHꢀCH2), 5.05 (d, 1 H, H-1%%), 4.96 (s, 1 H),
4.86 (s, 1 H), (H-1, H-1%), 4.60–4.50 (m, 2 H), 4.40 (dd,
J2,3 2.8, J1,2 1.3 Hz, 1 H, H-2), 4.36 (dd, J3,4 10.0 Hz, 1
H, H-3), 4.29–4.20 (m, 2 H), 4.15–4.05 (m, 3 H),
4.02–3.95 (m, 3 H), 3.88 (dd, 1 H, CH2ꢁCHꢀCH2), 3.84
(t, J4,5 10.0 Hz, 1 H, H-4), 2.39 (s, 3 H, CH3CO) 1.97
(s, 3 H, CH3CO). Anal. Calcd for C74H68O24: C, 66.27;
H, 5.07. Found: C, 66.40; H, 5.00.
Allyl 2-O-acetyl-3,4,6-tri-O-benzoyl-h-
ranosyl-(1“2) -3,4,6-tri-O-benzoyl-h- -mannopyran-
osyl-(1“3)-2-O-acetyl-h- -mannopyranoside (9).—
D-mannopy-
D
D
2-O-Acetyl-3,4,6-tri-O-benzoyl-h-
(1“2)-3,4,6-tri-O-benzoyl-h- -mannopyranosyl-(1“3)-
[2-O-acetyl-3,4,6-tri-O-benzoyl-h- -mannopyranosyl-
(1“2)-3,4,6-tri-O-benzoyl-h- -mannopyranosyl-(1“
D-mannopyranosyl-
Acetyl chloride (0.05 mL, 0.7 mmol) was added drop-
wise to a solution of 8 (1340 mg, 1 mmol) in MeOH (50
mL), and the mixture was stirred overnight at rt. TLC
(1.5:1 petroleum ether–EtOAc) indicated that the reac-
tion was complete, and the mixture was concentrated.
Purification by column chromatography (1.5:1
petroleum ether–EtOAc) gave 9 (1127 mmg, 90%) as a
D
D
D
6)]-4-O-acetyl-1,2-O-ethylidene-i-D-mannopyranose
(12).—Acetic anhydride (1 mL, 10 mmol) was added
dropwise to a solution of 11 (2186 mg, 1 mmol) in
pyridine (30 mL), and the mixture was stirred overnight
at rt. TLC (1.5:1 petroleum ether–EtOAc) indicated
that the reaction was complete. The mixture was di-
luted with CH2Cl2, washed with 1 N HCl, water, and
satd aq NaHCO3. The organic layers were combined,
dried, and concentrated. Purification by column chro-
matography (2:1 petroleum ether–EtOAc) quantita-
tively gave 12 as a colorless solid: mp 138–139 °C; [h]D
1
colorless solid: [h]D −10.3° (c 1.3, CHCl3); H NMR
(CDCl3): l 8.06–7.26 (m, 30 H, BzꢀH), 5.96 (dd,
J3,4=J4,5 10.0 Hz, 1 H, H-4%%), 5.90–5.78 (m, 3 H, H-4%,
H-3%%, CH2ꢁCHꢀCH2), 5.75 (dd, J2,3 3.0, J3,4 10.0 Hz, 1
H, H-3%), 5.65 (dd, J2,3 2.9, J1,2 1.4 Hz, 1 H, H-2%%), 5.62
(dd, J2,3 2.8, J1,2 1.4 Hz, 1 H, H-2), 5.38 (s, 1 H, H-1%%),
5.28 (dd, 1 H, CH2ꢁCHꢀCH2), 5.20 (dd, 1 H,
CH2ꢁCHꢀCH2), 5.12 (s, 1 H, H-1%), 4.84 (s, 1 H, H-1),
4.64–4.38 (m, 8 H), 4.18 (m, 1 H), 4.14 (dd, J2,3 3.0, J3,4
10.0 Hz, 1 H, H-3), 4.06 (dd, J3,4=J4,5 10.0 Hz, 1 H,
H-4), 3.95 (dd, 1 H, CH2ꢁCHꢀCH2), 3.78 (dd, J2,3 2.9,
J1,2 1.4 Hz, 1 H, H-2%), 3.70 (dd, 1 H, CH2ꢁCHꢀCH2),
2.22 (s, 3 H, CH3CO) 2.02 (s, 3 H, CH3CO); 13C NMR
(CDCl3): l 170.18, 169.84, (2 CH3CO), 166.28, 166.09,
165.49, 165.47, 164.44, 164.42, (6 C6H5CO), 99.97,
99.69, 97.97, (C-1I–III), 78.60, (C-3), 75.64, 72.37, 71.20,
70.83, 69.54, 69.48, 69.10, 68.97, 68.44, 68.07, 67.17,
64.92, 64.89, 62.30, (C-2,3,4,5,6I–III). Anal. Calcd for
C67H64O24: C, 64.22; H, 5.11. Found: C, 63.96; H, 5.14.
1
−4.5° (c 1.0, CHCl3); H NMR (CDCl3): l 8.09–7.25
(m, 60 H, BzꢀH), 6.03–5.82 (m, 7 H), 5.80 (dd, J 3.1, J
10.0 Hz, 1 H), 5.69 (dd, J 3.0, J 1.7 Hz, 1 H), 5.62 (dd,
J 3.0, J 1.7 Hz, 1 H), 5.28 (dd, 1 H, CH3ꢀCH), 5.22 (s,
1 H), 5.20 (t, J 10.0 Hz, 1 H), 5.18 (s, 1 H), 5.09 (s, 1
H), 5.08 (s, 1 H), 5.04 (s, 1 H), 4.63–4.44 (m, 12 H),
4.48 (dd, J 3.0, J 1.7 Hz, 1 H), 4.30 (dd, J 3.1, J 1.6 Hz,
1 H), 4.23 (dd, J 3.0, J 1.5 Hz, 1 H), 3.90–3.80 (m, 2
H), 3.60–3.55 (m, 1 H), 3.46–3.40 (m, 1 H), 2.12 (s, 3
H, CH3CO), 2.01 (s, 3 H, CH3CO), 2.00 (s, 3 H,
CH3CO), 1.46 (d, 3 H, CH3ꢀCH). Anal. Calcd for
C122H108O41: C, 65.71; H, 4.85. Found: C, 65.84; H
4.73.
2-O-Acetyl-3,4,6-tri-O-benzoyl-h-
(1“2)-3,4,6-tri-O-benzoyl-h- -mannopyranosyl-(1“3)-
[-2-O-acetyl-3,4,6-tri-O-benzoyl-h- -mannopyranosyl-
(1“2)-3,4,6-tri-O-benzoyl-h- -mannopyranosyl-(1“
6)]-1,2-O-ethylidene-i-D-mannopyranose (11).—The
D-mannopyranosyl-
D
2-O-Acetyl-3,4,6-tri-O-benzoyl-h-
(1“2)-3,4,6-tri-O-benzoyl-h- -mannopyranosyl-(1“3)-
[2-O-acetyl-3,4,6-tri-O-benzoyl -h- -mannopyranosyl-
(1“2)-3,4,6-tri-O-benzoyl-h- -mannopyranosyl-(1“
6)]-2,4-di-O-acetyl- -mannopyranose (13).—Com-
D-mannopyranosyl-
D
D
D
D
D
disaccharide donor 5 (1268 mg, 1.1 mmol) and the
monosaccharide acceptor 10 (103 mg, 0.5 mmol) were
dried together under high vacuum for 2 h, then dis-
solved in anhyd CH2Cl2 (30 mL). TMSOTf (15 mL, 0.08
equiv) was added dropwise at −20 °C with N2 protec-
D
pound 12 (2228 mg, 1 mmol) was treated with 90%
F3CCOOH (10 mL) at rt for 1 h, and the solution was
concentrated and co-concentrated with toluene. The
residue was dissolved in pyridine (10 mL) and treated

212
Y. Zhu et al. / Carbohydrate Research 337 (2002) 207–215
with Ac2O (3 mL) for 2 h. After conventional workup,
the residue was subjected to column chromatography
(1.5:1 petroleum ether–EtOAc) to yield 2-O-acetyl-
J 10.1 Hz, 2 H), 5.91 (t, J 10.1 Hz, 1 H), 5.88 (dd, J 3.0,
J 10.0 Hz, 1 H), 5.85 (dd, J 3.0, J 10.0 Hz, 1 H), 5.80
(dd, J 3.0, J 10.1 Hz, 1 H), 5.74 (dd, J 3.0, J 10.1 Hz,
1 H), 5.68–5.66 (m, 2 H), 5.64 (dd, J 3.0, J 1.5 Hz, 1
H), 5.45 (t, J 10.0 Hz, 1 H), 5.43 (s, 1 H), 5.17 (s, 1 H),
5.09 (s, 2 H), 4.61–4.43 (m, 13 H), 4.33 (dd, J 3.0, J 1.5
Hz, 1 H), 4.30 (dd, J 3.0, J 1.5 Hz, 1 H), 4.22–4.18 (m,
1 H), 3.89–3.84 (m, 1 H), 3.59–3.56 (m, 1 H), 2.26 (s,
3 H, CH3CO), 2.10 (s, 3 H, CH3CO), 2.02 (s, 3 H,
CH3CO), 2.00 (s, 3 H, CH3CO). Anal. Calcd for
C124H108Cl3NO42: C, 62.30; H, 4.52. Found: C, 62.45;
H, 4.40.
3,4,6-tri-O-benzoyl-a-
tri-O-benzoyl-a- -mannopyranosyl-(1“3)-[2-O-ace-
tyl-3,4,6-tri-O-benzoyl-a- -mannopyranosyl-(1“2)-
3,4,6-tri-O-benzoyl-a- -mannopyranosyl-(1“6)]-1,2,4-
tri-O-acetyl-a,b- -mannopyranose as a solid (1941 mg,
D
-mannopyranosyl-(1“2)-3,4,6-
D
D
D
D
85%). A solution of the solid (1142 mg, 0.5 mmol) and
ammonium carbonate (790 mg, 10 mmol) in DMF (20
mL) was stirred for 12 h at rt, at the end of which time
TLC (2:1 petroleum ether–EtOAc) indicated that the
reaction was complete. Water was added, and the mix-
ture was diluted with CH2Cl2, washed with 1 N HCl,
water, and satd aq NaHCO3. The organic layer was
combined, dried, and concentrated. The residue thus
obtained was passed through a short silica gel column
with 2:1 petroleum ether–EtOAc as the eluent to give
13 as a solid consisting predominantly of the a anomer
Allyl 2-O-acetyl-3,4,6-tri-O-benzoyl-h-D-mannopy-
ranosyl-(1“2)-3,4,6-tri-O-benzoyl-h- -mannopyran-
D
osyl - (1“3) - {2 - O - acetyl - 3,4,6 - tri - O - benzoyl - h -
mannopyranosyl - (1“2) - 3,4,6 - tri - O - benzoyl - h -
D
D
-
-
mannopyranosyl-(1“3)-[2-O-acetyl-3,4,6-tri-O-benzo-
yl-h- -mannopyranosyl-(1“2)-3,4,6-tri-O-benzoyl-h-
- mannopyranosyl - (1“6)] - 2,4 - di - O - acetyl - h -
mannopyranosyl-(1“6)}-2-O-acetyl-h- -mannopyran-
D
D
D-
D
1
(1021 mg, 91%): [h]D −13.2° (c 1.1, CHCl3); H NMR
oside (15).—The pentasaccharide donor 14 (1193 mg,
0.5 mmol) and the trisaccharide acceptor 9 (626 mg, 0.5
mmol) were dried together under high vacuum for 2 h,
then dissolved in anhyd CH2Cl2 (30 mL). TMSOTf (7.5
mL, 0.08 equiv) was added dropwise at −20 °C with N2
protection. The reaction mixture was stirred for 3 h,
during which time the reaction temperature was gradu-
ally raised to ambient temperature. Then the mixture
was neutralized with triethylamine and concentrated
under reduced pressure to an oily residue. Purification
by column chromatography (1:1 petroleum ether–
EtOAc) gave 15 (1426 mg, 82%) as a colorless solid:
[h]D −18.0° (c 0.9, CHCl3); 1H NMR (CDCl3): l
8.02–7.26 (m, 90 H, BzꢀH), 6.29 (t, J 9.9 Hz, 1 H), 6.03
(t, J 9.9 Hz, 1 H), 5.99–5.84 (m, 6 H), 5.78–5.70 (m, 3
H), 5.67–5.60 (m, 3 H), 5.56 (dd, J 3.0, J 1.5 Hz, 1 H),
5.48–5.30 (m, 6 H), 5.25 (s, 1 H), 5.23 (s, 1 H), 5.15 (s,
1 H), 5.12 (s, 1 H), 5.08 (s, 1 H), 5.04 (s, 1 H), 4.94 (s,
1 H), 4.88 (s, 1 H), 4.70–4.40 (m, 23 H), 4.22 (dd, J 3.0,
J 1.5 Hz, 1 H), 4.20 (dd, J 3.0, J 9.9 Hz, 1 H),
3.87–3.76 (m, 3 H), 3.70 (t, J 9.9 Hz, 1 H), 3.60–3.45
(m, 3 H), 2.29 (s, 3 H, CH3CO), 2.20 (s, 3 H, CH3CO),
2.08 (s, 3 H, CH3CO), 2.01 (s, 3 H, 2 CH3CO), 2.09 (s,
3 H, CH3CO), 1.95 (s, 6 H, 2 CH3CO); MALDI-TOF
MS: Calcd for C189H170O65: 3478.99 [M]. Found: 3479
[M]. Anal. Calcd for C189H170O65: C, 65.21; H, 4.89.
Found: C, 65.36; H, 4.76.
(CDCl3): l 8.01–7.26 (m, 60 H, BzꢀH), 5.95–5.83 (m, 7
H), 5.70 (dd, J 3.0, J 10.0 Hz, 1 H), 5.64 (dd, J 3.1, J
1.5 Hz, 1 H), 5.60 (dd, J 3.0, J 1.5 Hz, 1 H), 5.49 (dd,
J 3.0, J 1.5 Hz, 1 H), 5.40 (s, 1 H), 5.24 (s, 1 H), 5.22
(t, J 10.0 Hz, 1 H), 5.20 (s, 1 H), 5.08 (s, 1 H), 5.02 (s,
1 H), 4.66–4.37 (m, 14 H), 4.22 (dd, J 3.0, J 1.5 Hz, 1
H), 4.00–3.95 (m, 1 H), 3.77–3.73 (dd, 1 H), 3.58–3.55
(m, 1 H), 2.30 (s, 3 H, CH3CO), 2.19 (s, 3 H, CH3CO),
2.01 (s, 3 H, CH3CO), 2.00 (s, 3 H, CH3CO); 13C NMR
(CDCl3): l 170.52, 170.04, 169.31, 169.26, (4 CH3CO),
166.66, 166.53, 166.45, 166.15, 165.70, 165.67, 165.65,
165.55, 165.42, 165.28, 165.11, 164.98, (12 C6H5CO),
100.47, 99.76, 99.36, 98.97, 92.36 (C-1I–V), 79.08 (C-3),
77.28, 77.28 (C-2), 72.86, 71.32, 70.59, 70.06, 69.94,
69.73, 69.70, 69.67, 69.64, 69.61,69.58, 69.38, 69.11,
68.47, 68.20, 67.49, 67.12, 66.88, 63.97, 63.86, 63.33,
63.04, (C-2,3,4,5,6I–V). Anal. Calcd for C122H108O42: C,
65.24; H, 4.81. Found: C, 65.08; H, 4.88.
2-O-Acetyl-3,4,6-tri-O-benzoyl-h-
(1“2)-3,4,6-tri-O-benzoyl-h- -mannopyranosyl-(1“3)-
[2-O-acetyl-3,4,6-tri-O-benzoyl-h- -mannopyranosyl-
(1“2)-3,4,6-tri-O-benzoyl-h- -mannopyranosyl-(1“
6)]-2,4-di-O-acetyl-h- -mannopyranosyl trichloroace-
D-mannopyranosyl-
D
D
D
D
timidate (14).—The compound 13 (2244 mg, 1 mmol)
was dissolved in CH2Cl2 (20 mL), and CCl3CN (0.1
mL, 1 mmol) and DBU (14 mL, 0.1 mmol) were added.
The reaction mixture was stirred for 2 h, at the end of
which time TLC (2:1 petroleum ether–EtOAc) indi-
cated that the reaction was complete. Concentration of
the reaction mixture, followed by purification on a
silica gel column with 2:1 petroleum ether–EtOAc as
eluent furnished the pentasaccharide donor 14 as crys-
tals in a good yield (2150 mg, 90%): mp 135–137 °C;
Allyl 2-O-acetyl-3,4,6-tri-O-benzoyl-h-D-mannopy-
ranosyl-(1“2)-3,4,6-tri-O-benzoyl-h- -mannopyran-
D
osyl - (1“3) - {2 - O - acetyl - 3,4,6 - tri - O - benzoyl - h -
mannopyranosyl - (1“2) - 3,4,6 - tri - O - benzoyl - h -
D
D
-
-
mannopyranosyl-(1“3)-[2-O-acetyl-3,4,6-tri-O-benzo-
yl-h- -mannopyranosyl-(1“2)-3,4,6-tri-O-benzoyl-h-
-mannopyranosyl-(1“6)]-2,4-di-O-acetyl-h- -manno-
pyranosyl-(1“6)}-2,4-di-O-acetyl-h- -mannopyran-
D
D
D
1
[h]D −9.5° (c 1.3, CHCl3); H NMR (CDCl3): l 9.03
D
(s, 1 H, CꢁNH), 8.10–7.26 (m, 60 H, BzꢀH), 6.35 (d,
J1,2 1.5 Hz, 1 H, H-1), 6.05 (t, J 10.0 Hz, 1 H), 5.96 (t,
oside (16).—Acetic anhydride (1 mL, 10 mmol) was
added dropwise to a solution of 15 (1043 mg, 0.3 mmol)

Y. Zhu et al. / Carbohydrate Research 337 (2002) 207–215
213
signals overlapped); MALDI-TOF MS: Calcd for
C51H86O41: 1354.46 [M]. Found: 1354.66 [M].
in pyridine (20 mL), and the mixture was stirred
overnight at rt. TLC (1.5:1 petroleum ether–EtOAc)
indicated that the reaction was complete. The mixture
was diluted with CH2Cl2, washed with 1 N HCl, water,
and satd aq NaHCO3. The organic layers were com-
bined, dried, and concentrated. Purification by column
chromatography (1.5:1 petroleum ether–EtOAc) gave
16 quantitatively as a colorless solid: [h]D −14.5° (c
Allyl 2-O-acetyl-3,4,6-tri-O-benzoyl-h-
ranosyl-(1“2)-3,4,6-tri-O-benzoyl-h- -mannopyran-
osyl - (1“3) - 2 - O - benzoyl - 4,6 - O - benzylidene-h-
D-mannopy-
D
D
-
mannopyranoside (22).—Compound 7 was benzoylated
with BzCl–pyridine to furnish 22 as a foamy solid in
quantitative yield: [h]D −17.7° (c 1.0, CHCl3); 1H
NMR (CDCl3): l 8.02–7.33 (m, 35 H, BzꢀH), 6.00 (t, J
10.0 Hz, 1 H), 5.87 (m, 1 H, CH2ꢁCHꢀCH2ꢀ), 5.84 (dd,
J 3.0, J 10.0 Hz, 1 H), 5.78 (t, J 10.0 Hz, 1 H), 5.75 (dd,
J 2.8, J 10.0 Hz, 1 H), 5.70 (dd, J2,3 2.9, J1,2 1.3 Hz, 1
H, H-2), 5.58 (s, 2 H, H-1, H-2%%), 5.46 (s, 1 H, PhꢀCH),
5.33 (dd, 1 H, CH2ꢁCHꢀCH2), 5.26 (dd, 1 H,
CH2ꢁCHꢀCH2), 5.11 (s, 1 H), 5.04 (s, 1 H), (H-1%,
H-1%%), 4.67–4.54 (m, 4 H), 4.36 (dd, J2,3 2.9, J1,2 1.2 Hz,
1 H, H-2%), 4.28 (m, 1 H), 4.23–4.17 (m, 3 H), 4.08 (m,
1 H), 3.99–3.92 (m, 3 H), 3.85 (t, J4,5 10.0 Hz, 1 H,
H-4), 2.02 (s, 3 H, CH3CO); 13C NMR (CDCl3): l
168.68 (CH3CO), 165.98, 165.63, 165.30, 165.13, 164.67,
164.67, 164.45, (7 C6H5CO), 136.59, 118.18,
(CH2ꢁCHꢀCH2ꢀ), 101.51, (PhꢀC), 99.15, 98.47, 97.27,
(C-1I–III), 78.74, (C-3), 75.20, 71.67, 71.52, 70.22, 69.25,
69.06, 69.06, 69.00, 68.34, 68.05, 66.64, 66.29, 63.23,
63.16, 62.16, (C-2,3,4,5,6I–III, CH2ꢁCHꢀCH2ꢀ). Anal.
Calcd for C79H70O24: C, 67.62; H, 4.99. Found: C,
67.67; H, 5.01.
1
1.0, CHCl3); H NMR (CDCl3): l 8.02–7.26 (m, 90 H,
BzꢀH), 6.31 (t, J 9.9 Hz, 1 H), 6.01 (t, J 9.9 Hz, 1 H),
5.98–5.83 (m, 7 H), 5.78–5.70 (m, 3 H), 5.67–5.60 (m,
3 H), 5.56 (dd, J 3.0, J 1.5 Hz, 1 H), 5.48 (t, J 9.9 Hz,
1 H), 5.45–5.30 (m, 5 H), 5.23 (s, 1 H), 5.20 (s, 1 H),
5.12 (s, 1 H), 5.10 (s, 1 H), 5.08 (s, 1 H), 5.03 (s, 1 H),
4.95 (s, 1 H), 4.92 (s, 1 H), 4.70–4.42 (m, 23 H), 4.25
(dd, J 3.0, J 1.5 Hz, 1 H), 4.20 (dd, J 3.0, J 9.9 Hz, 1
H), 3.87–3.76 (m, 2 H), 3.74 (t, J 9.9 Hz, 1 H),
3.60–3.45 (m, 3 H), 2.28 (s, 3 H, CH3CO), 2.23 (s, 3 H,
CH3CO), 2.08 (s, 3 H, CH3CO), 2.01 (s, 3 H, 2
CH3CO), 2.00 (s, 3 H, CH3CO), 2.09 (s, 3 H, CH3CO),
1.96 (s, 3 H, CH3CO); 13C NMR (CDCl3): l 170.11,
170.08, 169.56, 169.31, 169.82, 169.79, 169.76, (7
CH3CO), 165.92, 165.89, 165.83, 165.75, 165.56, 165.51,
165.28, 165.20, 165.01, 165.05, 164.99, 164.95, 164.89,
164.68, 164.56, 164.52, 164.48, 164.27, (18 C6H5CO),
99.73, 99.53, 99.49, 99.45, 98.90, 98.19, 97.20, 96.03,
(C-1I–VIII), 77.76, 77.42, (C-3), 73.59, 73.47, 73.22,
70.46, 70.25, 70.10, 69.85, 69.31, 69.17, 68.47, 68.24,
68.10, 66.70, 66.56, 66.42, 66.17, 65.83, 63.25, 63.05,
62.64, 62.27, 61.90, (C-2,3,4,5,6I–VIII, some signals over-
lapped); MALDI-TOF MS: Calcd for C191H172O66:
3521.01 [M]. Found: 3521 [M]. Anal. Calcd for
Allyl 2-O-acetyl-3,4,6-tri-O-benzoyl-h-
ranosyl-(1“2)-3,4,6-tri-O-benzoyl-h- -mannopyran-
osyl-(1“3)-2-O-benzoyl-h- -mannopyranoside (23).—
D-mannopy-
D
D
Acetyl chloride (0.05 mL, 0.7 mmol) was added drop-
wise to a solution of the trisaccharide 22 (1402 mg, 1
mmol) in anhyd MeOH (50 mL). The solution was
sealed in a flask and stirred for 2 h at rt. The reaction
was monitored by TLC until the starting material dis-
appeared, at which time the solution was neutralized
with Et3N, then concentrated to dryness. The residue
was passed through a short silica gel column to give 23
(1246 mg, 96%) as foamy solid that was directly used
for the further reaction: [h]D −11.8° (c 1.0, CHCl3); 1H
NMR (CDCl3): l 8.02–7.33 (m, 35 H, BzꢀH), 5.96–
5.80 (m, 4 H, H-4%, H-4%%, H-3%, CH2ꢁCHꢀCH2ꢀ), 5.71
(dd, J2,3 3.0, J3,4 10.0 Hz, 1 H, H-3%), 5.63 (dd, J2,3 2.9,
J1,2 1.3 Hz, 1 H, H-2%%), 5.60 (dd, J2,3 2.8, J1,2 1.2 Hz, 1
H, H-2), 5.58 (d, J1,2 1.2 Hz, 1 H, H-1), 5.30 (dd, 1 H,
CH2ꢁCHꢀCH2), 5.22 (dd, 1 H, CH2ꢁCHꢀCH2), 5.11 (d,
1 H, H-1%%), 5.04 (d, 1 H, H-1%), 4.59–4.39 (m, 8 H),
4.28 (t, J4,5 10.0 Hz, 1 H, H-4), 4.20 (dd, J2,3 2.8, J3,4
10.0 Hz, 1 H, H-3), 4.04–3.97 (m, 3 H), 3.96 (dd, J2,3
3.0 Hz, 1 H, H-2%), 3.79 (m, 1 H), 2.05 (s, 3 H, CH3CO);
13C NMR (CDCl3): l 168.78 (CH3CO), 166.21, 165.93,
165.54, 165.20, 164.97, 164.65, 164.48, (7 C6H5CO),
133.03, 117.67, (CH2ꢁCHꢀCH2ꢀ), 100.38, 98.23, 96.29,
(C-1I–III), 76.84, (C-3), 74.47, 72.05, 71.89, 70.32, 69.09,
68.95, 68.84, 68.09, 68.01, 67.62, 67.21, 67.05, 66.83,
63.06, 61.86, (C-2,3,4,5,6I–III, CH2ꢁCHꢀCH2ꢀ). Anal.
C
191H172O66: C, 65.11; H, 4.89. Found: C, 65.27; H,
4.81.
Allyl h-
osyl-(1“3)-{h-
pyranosyl-(1“3)-[h-
mannopyranosyl-(1“6)]-h-
h- -mannopyranoside (17).—A saturated solution of
D
-mannopyranosyl-(1“2)-h-
-mannopyranosyl-(1“2)-h-
-mannopyranosyl-(1“2)-h-
-mannopyranosyl-(1“6)}-
D
-mannopyran-
D
D
-manno-
D
D -
D
D
ammonia in MeOH (5 mL) was added to a solution of
16 (704 mg, 0.2 mol) in MeOH (4 mL). After a week at
rt, the reaction mixture was concentrated, and the
residue was purified by chromatography on Sephadex
LH-20 (MeOH) to afford 17 (230 mg, 85%) as a syrup;
1H NMR (D2O): l 5.87 (m, 1 H, CH2ꢁCHꢀCH2), 5.31
(s, 1 H), 5.28 (dd, 1 H, CH2ꢁCHꢀCH2), 5.25 (s, 1 H),
5.20 (dd, 1 H, CH2ꢁCHꢀCH2), 5.08 (s, 1 H), 4.95 (s, 3
H), 4.80 (s, 1 H), 4.60 (s, 1 H), 4.05–3.53 (m, 50 H); 13
NMR (D2O): 136.88, 118.54, (CH2ꢁCHꢀCH2),
C
l
101.98, 101.86, 101.86, 100.56, 100.36, 100.28, 98.99,
97.60, (C-1I–VIII), 78.44, 78.38, (C-3), 72.75, 72.26,
70.71, 70.22, 69.85, 69.58, 69.50, 69.08, 66.42, 66.32,
66.24, 66.03, 65.24, 65.03, 64.65, 60.80, 60.68, 60.48,
59.96, 58.23, (C-2,3,4,5,6I–VIII, CH2ꢁCHꢀCH2, some

214
Y. Zhu et al. / Carbohydrate Research 337 (2002) 207–215
Calcd for C72H66O23: C, 66.56; H, 5.08. Found: C,
67.47; H, 5.01.
2-O-Acetyl-3,4,6-tri-O-benzoyl-h-
(1“2)-3,4,6-tri-O-benzoyl-h- -mannopyranosyl-(1“3)-
4,6-di-O-acetyl-2-O-benzoyl-h- -mannopyranosyl tri-
D-mannopyranosyl-
D
Allyl 2-O-acetyl-3,4,6-tri-O-benzoyl-h-
ranosyl-(1“2)-3,4,6-tri-O-benzoyl-h- -mannopyran-
osyl-(1“3)-4,6-di-O-acetyl-2-O-benzoyl-h- -manno-
D
-mannopy-
D
D
chloroacetimidate (26).—Compound 25 (537 mg, 0.4
mmol) was dissolved in CH2Cl2 (20 mL), then CCl3CN
(0.1 ml, 2 mmol) and DBU (14 mL, 0.18 mmol) were
added. The reaction mixture was stirred for 2 h, at the
end of which time TLC (2:1 petroleum ether–EtOAc)
indicated that the reaction was complete. Concentra-
tion of the reaction mixture, followed by purification
on a silica gel column with 2:1 petroleum ether–EtOAc
as the eluent furnished 26 as crystals in good yield (535
D
pyranoside (24).—Compound 23 was acetylated with
Ac2O–pyridine to furnish 24 as a foamy solid in quan-
titative yield: [h]D −7.6° (c 1.0, CHCl3); 1H NMR
(CDCl3): l 8.02–7.33 (m, 35 H, BzꢀH), 5.95–5.78 (m, 4
H, H-4%, H-4%%, H-3%%, CH2ꢁCHꢀCH2ꢀ), 5.63 (dd, J2,3
3.0, J3,4 10.0 Hz, 1 H, H-3%), 5.58 (s, 2 H, H-2, H-2%%),
5.53 (t, J3,4 10.0 Hz, 1 H, H-4), 5.37 (s, 1 H, H-1), 5.33
1
(dd,
1
H, CH2ꢁCHꢀCH2), 5.25 (dd,
1
H,
mg, 90%): H NMR (CDCl3): l 8.79 (s, 1 H, NꢁH),
CH2ꢁCHꢀCH2), 5.07 (s, 1 H, H-1), 4.99 (s, 1 H, H-1),
4.52–4.41 (m, 7 H), 4.29–4.15 (m, 4 H), 4.04 (m, 1 H),
3.91 (m, 1 H), 2.13 (s, 3 H, CH3CO), 2.12 (s, 3 H,
CH3CO), 1.99 (s, 3 H, CH3CO); 13C NMR (CDCl3): l
170.19, 169.38, 168.70, (3 CH3CO), 165.85, 165.58,
165.41, 165.16, 164.78, 164.43, 164.43, (7 C6H5CO),
133.18, 118.25, (CH2ꢁCHꢀCH2ꢀ), 99.65, 99.36, 96.09,
(C-1I–III), 76.80, (C-3), 74.74, 71.33, 69.71, 69.24, 69.14,
69.10, 68.94, 68.45, 68.13, 67.42, 66.57, 66.48, 62.94,
62.82, 62.08, (C-2,3,4,5,6I–III, CH2ꢁCHꢀCH2ꢀ). Anal.
Calcd for C76H70O25: C, 65.99; H, 5.07. Found: C,
66.17; H, 5.01.
8.02–7.23 (m, 35 H, BzꢀH), 6.52 (s, 1 H, H-1), 5.95 (t,
J 10.0 Hz, 1 H), 5.89 (t, J 10.0 Hz, 1 H), (H-4%, H-4%%),
5.79–5.75 (m, 2 H, H-2, H-3%%), 5.66 (t, J3,4 10.0 Hz, 1
H, H-4), 5.62 (dd, J2,3 3.0, J3,4 10.0 Hz, 1 H, H-3%), 5.56
(dd, J2,3 2.8, J1,2 1.2 Hz, 1 H, H-2%%), 5.38 (s, 1 H, H-1%%),
5.03 (s, 1 H, H-1%), 4.52–4.35 (m, 7 H), 4.25–4.18 (m,
4 H), 2.13 (s, 3 H, CH3CO), 2.08 (s, 3 H, CH3CO), 1.96
(s, 3 H, CH3CO). Anal. Calcd for C75H66Cl3NO25: C,
60.52; H, 4.44. Found: C, 60.37; H, 4.51.
Methyl 2-O-acetyl-3,4,6-tri-O-benzoyl-h-
ranosyl-(1“2)-3,4,6-tri-O-benzoyl-h- -mannopyran-
osyl-(1“3)-4,6-di-O-acetyl-2-O-benzoyl-h- -manno-
pyranosyl-(1“2)-3,4,6-tri-O-benzoyl-h- -mannopy-
ranosyl-(1“2)-3,4,6-tri-O-benzoyl-h- -mannopyran-
osyl-(1“2)-3,4,6-tri-O-benzoyl-h- -mannopyranoside
D-mannopy-
D
D
2-O-Acetyl-3,4,6-tri-O-benzoyl-h-
(1“2)-3,4,6-tri-O-benzoyl-h- -mannopyranosyl-(1“3)-
4,6-di-O-acetyl-2-O-benzoyl-h,i- -mannopyranose (25).
D
-mannopyranosyl-
D
D
D
D
D
—To a solution of 24 (691 mg, 0.5 mmol) in 90%
AcOH (10 mL) containing sodium acetate (293 mg, 3
mmol) was added PdCl2 (89 mg, 0.5 mmol), and the
mixture was stirred for 12 h, at the end of which time
TLC (2:1 petroleum ether–EtOAc) indicated that the
reaction was complete. The mixture was diluted with
CH2Cl2 (30 mL) and washed with water and satd aq
NaHCO3. The organic layer was concentrated under
reduced pressure, and the residue thus obtained was
passed through a short silica gel column with 2:1
petroleum ether–EtOAc as the eluent to give 25 as a
foamy solid (604 mg, 90%): [h]D −29.8° (c 1.2,
CHCl3); 1H NMR (CDCl3): l 8.02–7.23 (m, 35 H,
BzꢀH), 5.92 (t, J 10.0 Hz, 1 H), 5.86 (t, J 10.0 Hz, 1 H),
(H-4%, H-4%%), 5.79 (dd, J 2.8, J 10.0 Hz, 1 H), 5.61 (dd,
J 2.8, J 10.0 Hz, 1 H), (H-3%, H-3%%), 5.58 (dd, J2,3 2.8,
J1,2 1.2 Hz, 1 H, H-2), 5.55 (s, 1 H, H-1), 5.51 (t, J3,4
10.0 Hz, 1 H, H-4), 5.39 (dd, J2,3 2.8, J1,2 1.2 Hz, 1 H,
H-2%%), 5.36 (s, 1 H, H-1%%), 4.99 (s, 1 H, H-1%), 4.60–4.39
(m, 7 H), 4.23 (m, 2 H, H-3, H-2%), 4.16 (m, 1 H), 4.05
(m, 1 H), 2.10 (s, 3 H, CH3CO), 2.09 (s, 3 H, CH3CO),
1.96 (s, 3 H, CH3CO); 13C NMR (CDCl3): l 170.32,
169.44, 168.73, (3 CH3CO), 165.90, 165.73, 165.40,
165.19, 164.81, 164.52, 164.44, (7 C6H5CO), 99.46,
99.44, 91.71, (C-1I–III), 76.70, (C-3), 73.98, 71.51, 69.66,
69.42, 69.24, 69.15, 68.97, 68.39, 67.37, 66.68, 66.57,
63.03, 62.87, 62.15, (C-2,3,4,5,6I–III). Anal. Calcd for
C73H66O25: C, 65.28; H, 4.92. Found: C, 65.07; H, 5.01.
(27).—Compounds 26 (446 mg, 0.3 mmol) and 21 (437
mg, 0.3 mmol) were dried together under high vacuum
for 2 h, then dissolved in anhyd CH2Cl2 (50 mL).
TMSOTf (5 mL, 0.08 equiv) was added dropwise at
−20 °C with N2 protection. The reaction mixture was
stirred for 2 h, during which time the reaction tempera-
ture was gradually raised to ambient temperature. Then
the mixture was neutralized with triethylamine and
concentrated under reduced pressure to an oily residue.
Purification by column chromatography (1:1 petroleum
ether–EtOAc) gave 27 (545 mg, 65%) as a colorless
foamy solid: [h]D −17.1° (c 1.0, CHCl3); 1H NMR
(CDCl3): l 8.19–7.24 (m, 80 H, BzꢀH), 6.06 (t, J 10.0
Hz, 1 H), 6.00–5.75 (m, 10 H), 5.64–5.60 (m, 2 H),
5.53 (s, 1 H), 5.40 (s, 2 H), 5.29 (s, 1 H), 5.10 (s, 1 H),
5.06 (s, 1 H), (six H-1), 4.65–4.21 (m, 18 H), 4.17–4.12
(m, 2 H), 4.00 (m, 1 H), 3.90 (m, 1 H), 3.34 (s, 3 H,
OCH3), 2.04 (s, 3 H, CH3CO), 1.97 (s, 3 H, CH3CO),
1.94 (s, 3 H, CH3CO); 13C NMR (CDCl3): l 170.80,
169.90, 169.17, (3 CH3CO), 166.64, 166.56, 166.33,
166.28, 166.20, 166.09, 165.88, 165.77, 165.66, 165.50,
165.42, 165.38, 165.31, 165.24, 164.96, 164.75, (16
C6H5CO), 100.21, 100.04, 99.90, 99.90, 99.51, 99.51,
(C-1I–VI), 76.66, (C-3), 72.09, 72.00, 71.90, 71.72, 71.46,
70.68, 70.60, 69.78, 69.78, 69.66, 69.66, 69.56, 69.50,
68.77, 68.22, 68.22, 67.90, 67.90, 67.07, 67.21, 67.09,
66,55, 64.09, 63.86, 63.86, 63.72, 63.54, 63.07, 62.95,
62.88, 62.49, 62.40, (C-2,3,4,5,6I–VI). Anal. Calcd for

Y. Zhu et al. / Carbohydrate Research 337 (2002) 207–215
215
(b) Siliciano, R. F.; Pratt, J. C.; Schmidt, R. E.; Ritz, J.;
Reinherz, E. L. Nature 1985, 317, 423–428;
(c) Yang, S. Y.; Chouaib, S.; Dupont, B. J. Immunol.
1986, 137, 1097–1102;
C155H134O50: C, 66.57; H, 4.80. Found: C, 66.42; H,
4.91.
Methyl h-
ranosyl-(1“3)-h-
pyranosyl - (1“2) - h -
D
-mannopyranosyl-(1“2)-h-
-mannopyranosyl(1“2)-h-
- mannopyranosyl - (1“2) - h - D-
D
-mannopy-
D
D
-manno-
(d) Hunig, T.; Tiefenthaler, G.; Meyer zum Bu¨schenfelde,
K.-H.; Meuer, S. C. Nature 1987, 326, 298–303;
(e) Qin, L.; Chaving, K. D.; Lin, J.; Yagita, H.;
Bromberg, J. S. J. Exp. Med. 1994, 179, 341–349.
2. Wyss, D. F.; Choi, J. S.; Li, J.; Knoppers, M. H.; Willis,
K. J.; Arulanandam, A. R. N.; Smolyar, A; Reinherz, E.
L.; Wagner, G. Science 1995, 269, 1273–1298.
3. Recny, M. A.; Luther, M. A.; Knoppers, M. H.; Neid-
hardt, E. A.; Khandekar, S. S.; Concino, M. F.; Shimke,
P. A.; Francis, M. A.; Moebius, U. J. Biol. Chem. 1992,
267, 22428–22434.
4. Arulanandam, A. R. N.; Smolyar, A; Reinherz, E. L.;
Wagner, G. Proc. Natl. Acad. Sci. USA 1993, 90, 11613–
11620.
5. Bewley, C. A.; Otero-Quintero, S. J. Am. Chem. Soc.
2001, 123, 3892–3902.
D
mannopyranoside (28).—A solution of 27 (279 mg, 0.1
mmol) in MeOH (4 mL) was added to a saturated
solution of ammonia in MeOH (5 mL). After a week at
rt, the reaction mixture was concentrated, and the
residue was purified by chromatography on Sephadex
LH-20 (MeOH) to afford 28 (85 mg, 85%) as a syrup:
1H NMR (D2O): l 5.30 (s, 1 H), 5.20 (s, 2 H), 4.94 (s,
1 H), 4.92 (s, 1 H), 4.89 (s, 1 H), 3.97–3.50 (m, 36 H),
3.29 (s, 3 H, OCH3). MALDI-TOF MS: Calcd for
C37H64O31: 1004.34 [M]. Found: 1004.46 [M].
6. Funayama, M.; Nishikawa, A.; Shinoda, T.; Fukazawa,
Y. Carbohydr. Res. 1983, 117, 229–239.
7. (a) Wang, W.; Kong, F. J. Org. Chem. 1998, 63, 5744–
5745;
Acknowledgements
(b) Wang, W.; Kong, F. Angew. Chem., Int. Ed. Engl.
1999, 38, 1247–1250.
This work was supported by The Chinese Academy
of Sciences (Projects KJ952J1510 and KIP-
RCEES9904) and by The National Natural Science
Foundation of China (Projects 29802009, 39970864,
and 30070815).
8. (a) Wang, W.; Kong, F. J. Org. Chem. 1999, 64, 5091–
5095;
(b) Wang, W.; Kong, F. Carbohydr. Res. 1999, 315,
117–126;
(c) Wang, W.; Kong, F. Tetrahedron Lett. 1998, 39,
1937–1940.
9. Zhu, Y.; Kong, F. Synlett 2000, 663–667.
10. Zhu, Y.; Kong, F. Synlett 2000, 1783–1788.
11. Wang, W.; Kong, F. J. Carbohydr. Chem. 1999, 18,
264–272.
12. Yang, G.; Kong, F. Synlett 2000, 1427–1430.
13. Unverzagt, C. Angew. Chem., Int. Ed. Engl. 1994, 33,
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