A first total synthesis of ganglioside HLG-2

Article abstract of DOI:10.1002/chem.200802706

A first synthesis of the neuri-tegenic ganglioside HLG-2, which was identified in extracts of the sea cucumber Holothuria leucospilota, is described. The characteristic sequence of the trisaccharide part, α-N-glycolylsial-yl-(2,4)-& α-N-acetylsialyl-(2,6)-glucoside, was efficiently assembled by coupling of a highly active N-2,2,2-trichloro- ethoxycarbonyl (Troc)-protected sialyl donor and a 1,5-lactamized sialyl ac- ceptor with high stereoselectivity. The corresponding trisaccharyl imidate donor was directly glycosidated with the primary hydroxyl group of the ceramide part, producing protected HLG-2 in relatively high yield, global deprotection of which furnished ganglioside HLG-2 in highly pure form.

Full text of DOI:10.1002/chem.200802706

FULL PAPER
DOI: 10.1002/chem.200802706
A First Total Synthesis of Ganglioside HLG-2**
Yuki Iwayama,[a, b] Hiromune Ando,*[a, b] Hideharu Ishida,[c] and Makoto Kiso*[a, b]
Abstract: A first synthesis of the neuri-
tegenic ganglioside HLG-2, which was
identified in extracts of the sea cucum-
ber Holothuria leucospilota, is de-
scribed. The characteristic sequence of
the trisaccharide part, a-N-glycolylsial-
yl-(2,4)-a-N-acetylsialyl-(2,6)-glucoside,
was efficiently assembled by coupling
of a highly active N-2,2,2-trichloro-
ethoxycarbonyl (Troc)-protected sialyl
donor and a 1,5-lactamized sialyl ac-
ceptor with high stereoselectivity. The
corresponding trisaccharyl imidate
donor was directly glycosidated with
the primary hydroxyl group of the ce-
ramide part, producing protected
HLG-2 in relatively high yield, global
deprotection of which furnished gangli-
oside HLG-2 in highly pure form.
Keywords:
glycolipids
gangliosides
natural products
·
·
·
sialic acids · total synthesis
Introduction
many gangliosides, such as sialyl Lewis X,[2] GQ1b,[3] and
GQ1ba,[4] have been initially synthesized in a stereoselective
and convergent manner, and then utilized in biological stud-
ies.[5] Meanwhile, a variety of gangliosides have been isolat-
ed from echinoderms, and their unique structures have been
characterized. To date, several series of echinodermatous
gangliosides have been identified; for example, the LLG,[6]
HLG,[7] AG,[8] SJG,[9] and LMG[10] series. The attraction of
echinodermatous gangliosides is that they show neuritegenic
activity similar to that of mammalian gangliosides.[11] How-
ever, their structure–activity relationships have yet to be de-
lineated by using structurally homogeneous gangliosides.
Ganglioside HLG-2 is present in the sea cucumber Holo-
thuria leucospilota, and was first isolated by Higuchi et al.[7]
Ganglioside HLG-2 showed neuritegenic activity toward the
rat pheochromocytoma cell line PC-12 in the presence of
nerve growth factor, and its activity was as potent as that of
mammalian ganglioside GM1. As depicted in Figure 1, sev-
eral unique structural features are present within the HLG-
Gangliosides, sialic acid-containing glycosphingolipids, have
been attracting much attention due to their diverse biologi-
cal functions. In mammals, gangliosides function as media-
tors for cell–cell recognition, virus–cell recognition, toxin–
cell recognition, and cell signaling, and are also relevant to
neural network formation, fertilization, and oncogenesis.[1]
The mammalian gangliosides, a family comprised of six
major series (the hemato, ganglio, lacto, neolacto, globo,
and isoglobo series), have been targeted by chemical syn-
thetic studies over the last two decades. In our laboratory,
[a] Y. Iwayama, Dr. H. Ando, Dr. M. Kiso
Department of Applied Bioorganic Chemistry
Faculty of Applied Biological Sciences, Gifu University
1-1 Yanagido, Gifu-shi, Gifu 501-1193 (Japan)
E-mail: hando@gifu-u.ac.jp
2 molecule. An aACHTUNTRGNEUNG(2,4)-linkage between sialic acids is seen
[b] Y. Iwayama, Dr. H. Ando, Dr. M. Kiso
Institute for Integrated Cell-Material Sciences
Kyoto University
only in HLG series gangliosides (HLG-2 and HLG-3), and
the tandem of N-glycolylsialic acid (NeuGc) and N-acetyl-
sialic acid (NeuAc) is a further characteristic of HLG series
gangliosides. In addition, the ceramide part in HLG-2 (1
and 2), which comprises a mammalian-type unsaturated
sphingosine and an a-hydroxy fatty acid, is the sole combi-
nation among the echinodermatous gangliosides found to
date. Compound 1 was isolated from Holothuria leucospilota
as a major homologue of HLG-2.
69 Konoe-cho, Yoshida, Sakyo-ku, Kyoto 606-8501 (Japan)
Fax : (+81)58-293-3189
[c] Dr. H. Ishida
Department of Applied Bioorganic Chemistry
Faculty of Applied Biological Sciences, Gifu University
1-1 Yanagido, Gifu-shi, Gifu 501-1193 (Japan)
[**] Part 148 of the series: Synthetic studies on sialoglycoconjugates. For
part 147, see: A. Imamura, H. Ando, H. Ishida, M. Kiso, J. Org.
Chem. 2009, in press.
Previously, our group embarked on new research concern-
ing the systematic synthesis of echinodermatous gangliosides
with a view to developing their potential as drug leads for
Supporting information for this article is available on the WWW
under http://dx.doi.org/10.1002/chem.200802706.
Chem. Eur. J. 2009, 15, 4637 – 4648
ꢀ 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
4637

In the synthesis of glucosyl acceptor 8, we addressed the
chemical discrimination in etherification of the C-2 and C-3
hydroxyl groups in 4,6-benzylidenated glucoside 16[20]
(Scheme 3). We first tried Hungꢁs method (i) TMSCl, Et3N;
ii) Et3SiH, PhCHO, TMSOTf).[21] In the case of 16, the 3-O-
benzylated derivative 17 was generated in 61% yield and
was accompanied by several unidentified by-products. In
scaling-up this reaction, the generation of these unknown
by-products could not be suppressed. Conversely, regioselec-
Figure 1. Ganglioside HLG-2.
combatting neural disorders, and recently we reported a syn-
thesis of the glycan part of HLG-2.[12] In this paper, we de-
scribe in detail the first total synthesis of HLG-2.
Results and Discussion
According to the literature on ganglioside synthesis, the con-
jugation of the glycan part with the ceramide may be con-
ducted using several approaches. One major approach ex-
ploited the pre-incorporation of 2-azido-sphingosine at the
reducing end of the glycan chain, which was followed by as-
sembly of the ceramide structure.[13] Alternatively, in anoth-
er approach, the ceramide part was glycosylated with the
full-length glycan part to directly fashion a ganglioside
framework.[14] Although this direct method tends to de-
crease the coupling yields of large ganglioside syntheses, it
can offer high efficiency for small ganglioside syntheses.
Therefore, our disconnection of target compound 1 gave tri-
saccharide glycosyl donor 3, which bears a benzoyl group at
C-2 of glucose as a b-directing functionality in glycosylation,
and ceramide acceptor 4 (Scheme 1). The trisaccharide 3,
Scheme 1. Retrosynthetic analysis of the glycan part of 1. SE=2-(trime-
thylsilyl)ethyl, Bn=benzyl, MBn=p-methoxybenzyl.
which has the sequence Neu5Gc-aACTHNUGTRNENUG(2,4)-Neu5Ac-aHCATUNGTRENN(GUN 2,6)-Glc,
was further compartmentalized into N-2,2,2-trichloroethoxy-
carbonyl (Troc)-sialyl donor 5[15] and 1,5-lactamized sialyl
glucosyl acceptor 6,[12] which is a linchpin to construct the
Neu-aACHTUNGTRENNUNG(2,4)-Neu tandem structure. To synthesize the lacta-
mized sialyl glucosyl acceptor, N-trifluoroacetyl (TFAc)
sialyl donor 7[16] and glucosyl acceptor 8 were chosen. To in-
troduce the benzoyl group at the C-2 hydroxyl group of glu-
cose after a basic lactamization reaction, the C-2 hydroxyl
group was temporarily protected with the p-methoxybenzyl
(MBn) group. The 2-(trimethylsilyl)ethyl (SE) group was
chosen as a tentative aglycon during manipulation of the
glycan part, based on our reported results of ganglioside
syntheses.[17]
On the other hand, the ceramide part was disconnected at
the amide bond, affording (2S,3R)-2-amino-heptadec-4-ene-
1,3-diol 9 and an a-hydroxy fatty acid 10. According to an
article by Murakami et al.,[18] the coupling reaction of Gar-
nerꢁs aldehyde 11[19] and alkyne 12 was expected to furnish a
trans-alkene moiety within 9. Fatty acid 10 was fragmented
into oxirane 14 and alkyne 15 (Scheme 2).
Scheme 2. Retrosynthetic analysis of the ceramide part of 1.
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Chem. Eur. J. 2009, 15, 4637 – 4648

Synthesis of Ganglioside HLG-2
FULL PAPER
tive benzylation via the di-n-butylstannylidene intermedi-
ate[22] afforded 17 in moderate yield (53%) on a large scale,
concomitantly generating the 2-O-benzyl derivative in 34%
yield. In view of the practicalities, the stannylidene-mediat-
ed benzylation was used for conversion to 17. The C-2 hy-
droxyl group of 17 was protected with an MBn group in the
conventional manner (MBnCl, NaH/DMF), and then the
4,6-benzylidene group was reductively opened upon treat-
ment with DIBAL-H in toluene[23] to yield the 6-OH gluco-
syl acceptor 8. The position of the resulting free hydroxyl
group was confirmed by NMR analysis of compound 8 and
the corresponding acetylated derivative 8’. Comparing 8’
and 8, the signals of H-6a and H-6b were shifted to d=4.24
and 4.34 ppm from d=3.71 and 3.87 ppm, respectively.
90% yield (over two steps). The position of the acetal was
determined by comparison of the H NMR chemical shifts
1
of the H-7 signals of 24 and the corresponding acetylated
derivative 24’, similar to the case of compound 8. Com-
pound 24 was then converted into the 1,5-lactam form 25 in
95% yield by treatment with NaOMe in MeOH under
reflux in the presence of Drierite as a drying agent. To our
delight, the next sialylation of the diol acceptor 25 with N-
Troc sialyl donor 5 occurred exclusively at the C-4 hydroxyl
group in a stereoselective manner, delivering the HLG-2
glycan sequence 26 in 60% yield and the b-isomer 27 in 9%
yield. As previously reported, the anomeric configurations
of the new sialosides were determined on the basis of the
3
coupling constant between C-1 and H-3ax (26, JC1-H3ax
=
3
3.8 Hz; 27, JC1-H3ax =<1.0 Hz).[25] The isolated 26 was then
subjected to the reaction sequence for transformation to the
trichloroacetimidate form 34 as a trisaccharide glycosyl
donor. Thus, acid hydrolysis followed by conventional acety-
lation afforded 28. To open the lactam moiety, the hydrogen
of the lactam was substituted with a benzyloxycarbonyl
(Cbz) group by reaction with CbzOSu and DMAP, affording
29 in 79% yield. Prior to lactam opening, the MBn group at
the C-3 position of glucose was selectively removed by treat-
ment with DDQ and water,[26] and this was followed by in-
stallment of the benzoyl group as a stereo-directing element
in the final coupling reaction with the ceramide. Next, the
Troc group of sialic acid was replaced with a benzylglycolyl
group by subjecting 30 to reaction with Zn-Cu couple in
AcOH,[27] and this was followed by treatment with benzyl-
glycolyl chloride to afford 31 in 89% yield over two steps.
The lactam ring of 31 was then successfully hydrolyzed in a
7% triethylamine solution in MeCN/H2O (9:5) at 408C, and
Scheme 3. Synthesis of glucosyl acceptor 8. a) i) nBu2SnO/PhMe, reflux,
8 h; ii) then, BnBr, nBu4NBr, reflux, 8 h, 53%; b) MBnCl, NaH/DMF,
RT, 3 h; c) iBu2AlH/PhMe, RT, 18 h, 74% (2 steps); d) Ac2O, py, RT,
15 h, 97%.
The assembly of the trisaccharide sequence of HLG-2
commenced with synthesis of the 1,5-lactam-sialyl glucosyl
acceptor 25. In our previous study on the synthesis of the
HLG-2 glycan part,[12] the corresponding 9-O-benzoyl-4,7,8-
triol acceptor 19 was sialylated to yield the Neu-a
(2,6)-Glc sequence in 66%
yield, along with the b-isomer
(18%) and the Neu(2,8){Neu-
(2,4)}Neu(2,6)Glc tetrasacchar-
ACHTUNGTRENUN(NG 2,4)-Neu-
a
ACHTUNGTRENNUNG
G
ACHTUNGTRENNUNG
G
ACHTUNGTRENNUNG
ide 20 (8%) as a doubly-sialy-
lated by-product (Scheme 4). In
this study, to prevent the un-
wanted over-sialylation, the C-8
hydroxyl group was designed to
be protected as an 8,9-O-iso-
propylidene (Scheme 5). The a-
sialylation of the aforemen-
tioned glucosyl acceptor 8 with
N-TFAc sialyl donor 7 was pro-
moted by NIS/TfOH[24] in
MeCN/CH2Cl2 at ꢀ308C to
produce a-sialyl glucoside 21 in
75% yield along with b-isomer
22 (13%). The disaccharide was
deacetylated by treatment with
NaOMe in MeOH, and then
8,9-isopropylidenated by reac-
tion with 2-dimethoxypropane
and
(ꢁ)-10-camphorsulfonic
acid in MeCN to afford 24 in Scheme 4. Previous result relating to assembly of the HLG-2 glycan framework.
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4639

H. Ando, M. Kiso et al.
subsequent acetylation and methylation gave 32 in 73%
yield (over three steps). The Cbz group and benzyl groups
within 32 were hydrogenolyzed over Pd(OH)2, and re-acety-
lation of the liberated amine and hydroxyl groups afforded
the fully acylated trisaccharide 33. Finally, treatment of 33
with trifluoroacetic acid in CH2Cl2 followed by reaction
with CCl3CN and DBU[28] furnished the trisaccharide glyco-
syl donor 34.
Starting from 9-decen-1-ol 35, the known alkyne 12 was
synthesized by the following procedures reported in the lit-
erature[29] (Scheme 6). This conversion involved tosylation
of the hydroxyl group of 35, isobutylation with iBuMgBr
and Li2CuCl4, and 1,2-dibromination followed by eliminative
alkynylation, thereby generating 12 in 58% yield over four
steps. To assemble the erythro-sphingosine derivative, the
alkyne 12 in hand was hydrozirconated by treatment with
[Cp2Zr(H)Cl], and subsequently reacted with Garnerꢁs alde-
hyde 11 in the presence of ZnBr2 according to Murakamiꢁs
method.[18] This coupling reaction afforded erythro-sphingo-
sine 37 in 56% yield, which was accompanied by unidenti-
fied by-products. The cyclic isopropylaminal was then re-
Scheme 6. Synthesis of sphingosine 39. a) p-TsCl, py/CH2Cl2 2:3, RT,
08C, 2 h; b) iBuMgBr, Li2CuCl4/THF, ꢀ788C!RT, 6 h, 94% (2 steps);
c) Br2/CH2Cl2, 08C, 10 min; d) tBuOK, [18]crown-6/petroleum ether,
reflux, 3 h, 62% (2 steps); e) i) [Cp2Zr(H)Cl]/THF, RT, 1 h; ii) then 11,
ZnBr2, RT, 18 h, 56%; f) 80% aq. AcOH, 458C, 4 h, 67%; g) TFAcOH/
CH2Cl2, RT, 15 min, 81%. Ts=tosyl, Cp=cyclopentadienyl.
moved in 80% aqueous AcOH and subsequent exposure to
trifluoroacetic acid in CH2Cl2 yielded the unprotected sphin-
gosine 39, which was suitably predisposed for condensation
with an incoming fatty acid.
Scheme 5. Synthesis of trisaccharide glycosyl donor 34. a) NIS, TfOH, MS 3 ꢂ, MeCN/CH2Cl2 13:1, ꢀ308C, 3.5 h, 88% (a/b 75:13); b) 21, NaOMe,
MeOH, RT, 2 h, 94%; c) DMP, CSA/MeCN, RT, 2 h, 96%; d) Ac2O, py, RT, 2 h, 96%; e) NaOMe, Drierite/MeOH, reflux, 92 h, 95%; f) 5, NIS, TfOH,
MS 3 ꢂ, EtCN/CH2Cl2 9:1, ꢀ408C, 16 h, 69% (a/b 60:9); g) i) 26, 80% aq. AcOH, 458C, 17 h; ii) Ac2O, py, RT, 6 h, 82% (2 steps); h) CbzOSu, DMAP/
py, RT, 48 h, 79%; i) i) DDQ, H2O/CH2Cl2, RT, 2 h; ii) Bz2O, DMAP/py, RT, 20 h, 93% (2 steps); j) i) Zn-Cu/AcOH, RT, 45 min; ii) BnGcCl/THF, 1.5 h,
89% (2 steps); k) i) 10% Et3N solution in MeCN/H2O 2:1, 408C, 19 h; ii) Ac2O, DMAP/py, RT, 1 h; iii) MeI, K2CO3/DMF, RT, 1 h, 73% (3 steps);
l) i) H2, Pd(OH)2, AcOH, EtOH/THF (3:1), RT, 1 h; ii) Ac2O, DMAP/py, RT, 6.5 h, 89% (2 steps); m) i) TFA/CH2Cl2, RT, 4 h; ii) CCl3CN, DBU/CH2Cl2,
08C, 1 h, 87% (2 steps). NIS=N-iodosuccinimide, TfOH=trifluoromethanesulfonic acid, MS=molecular sieves, DMP=2,2-dimethoxypropane, CSA=
(ꢁ)-10-camphorsulfonic acid, Cbz=benzyloxycarbonyl, DMAP=4-dimethylaminopyridine, DDQ=2,3-dichloro-5,6-dicyano-p-benzoquinone, Bz=ben-
zoyl, Gc=glycolyl, TFA=trifluroacetic acid, TFAc=trifluoroacetyl, DBU=1,8-diazabicycloACTHNUGTRNEUNG[5.4.0]undec-7-ene.
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Synthesis of Ganglioside HLG-2
FULL PAPER
The synthesis of (R)-2-hydroxytetracosanoic acid deriva-
tive 46 commenced with the conversion of 1-icosanol 40 into
henicos-1-yne 15 (Scheme 7). Although Komori et al. have
previously reported a synthesis of 15,[30] which involved cou-
pling of 1-heptyne and 1-bromotetradecane and migration
of the triple bond, we were unable to reproduce their re-
ported yields for each reaction step. In this study, therefore,
we designed an alkyne moiety by the Corey–Fuchs ap-
proach.[31] Thus, 1-icosanol 40 was first converted into alde-
hyde 41 in 89% yield by Dess–Martin oxidation.[32] One-
carbon-extension of 41 by reaction with CBr4 and PPh3
yielded dibromoalkene 42, treatment of which with nBuLi
in THF at ꢀ788C afforded the terminal acetylene 15 in pure
form and in almost quantitative yield (93% over two steps).
Alkylation of 15 with the commercially available oxirane 14
was conducted according to an earlier report by Komori
et al.,[30] affording 43 in 78% yield. The secondary hydroxyl
group of 43 was protected with a benzoyl group, and hydro-
genolysis of the benzyl group and the triple bond, followed
by Dess–Martin oxidation, afforded a-benzoyloxy aldehyde
45 in 87% yield over two steps. The aldehyde 45 was then
oxidized to the carboxylic acid by the action of NaClO2 in
the presence of 2-methyl-2-butene[33] to quantitatively afford
the desired a-hydroxy fatty acid 46. The synthesized fatty
acid 46 and the aforementioned sphingosine 39 were cou-
pled under catalysis by 1-ethyl-3-(dimethylaminopropyl)car-
bodiimide hydrochloride in CH2Cl2, producing ceramide
framework 47 in 68% yield. The primary hydroxyl group at
C-1 was selectively protected as triisopropylsilyl (TIPS)
ether, allowing benzoylation of the remaining unprotected
hydroxyl group. Finally, the TIPS group was removed by the
action of TBAF in the presence of AcOH in THF, furnishing
ceramide acceptor 50.
As depicted in Scheme 8, coupling of the trisaccharide
glycosyl donor 34 (1.0 equiv) with the ceramide acceptor 50
(1.3 equiv), which was promoted by TMSOTf (0.8 equiv in
total), successfully afforded protected HLG-2 51 in 49%
yield. Finally, global deprotection of 51 delivered ganglio-
side HLG-2 1.
Scheme 8. Assembly of the fully protected HLG-2 and its deprotection.
a) TMSOTf,
AW-300/CH2Cl2,
08C!108C!RT,
17.5 h,
49%;
b) i) NaOMe, MeOH, RT, 4 h; ii) then H2O, RT, 116 h, quant. TMSOTf=
trimethylsilyl trifluoromethanesulfonate, AW-300=acid-washed 4 ꢂ mo-
lecular sieves.
In summary, we have presented the first synthesis of gan-
glioside HLG-2. In the assembly of the glycan part, NeuGc-
aACTHNUTRGENNU(G 2,4)-NeuAc-aHCATUNGTRENN(UGN 2,6)-Glc, the yield of the sialylation at the
C-4 hydroxyl group of the sialic acid residue was improved
by exploiting the 8,9-isopropylidenated 1,5-lactam-sialyl unit
as a novel glycosyl acceptor. The three chiral carbons of the
ceramide part were each efficiently established in a stereo-
selective manner. The final connection of the glycan and ce-
ramide parts was accomplished with relatively high yield.
We are now investigating the neuritegenic activity of syn-
thetic HLG-2 toward the PC-12 and Neuro2a cell lines.
Experimental Section
1
General procedures: H and 13C NMR spectra were recorded with Varian
Unity INOVA 400, INOVA 500, JEOL JNM-ECX400P, JNM-ECA500,
and JNM-ECA600 spectrometers. Chemical shifts are expressed in ppm
(d) relative to the signal of Me4Si as an internal standard. High-resolu-
tion mass spectrometry (HRMS) was performed with a Bruker Daltonics
micrOTOF (ESI-TOF) mass spectrometer. FAB mass spectra were re-
corded on a JEOL JMS-700/GI using m-nitrobenzyl alcohol (NBA) as a
matrix. MALDI-TOF mass spectra were recorded on a Bruker Autoflex
using a-cyano-4-hydroxy-cinnamic acid (CHCA) as a matrix. Specific ro-
tations were determined with a Horiba SEPA-300 high-sensitivity polar-
imeter. Molecular sieves were purchased from Wako Chemicals Inc. and
dried at 3008C for 2 h in a muffle furnace prior to use. Drierite was pow-
dered and dried at 3008C for 6 h in a muffle furnace prior to use. Sol-
vents as reaction media were dried over molecular sieves and used with-
Scheme 7. Synthesis of ceramide acceptor 50. a) Dess–Martin periodi-
nane, NaHCO3/CH2Cl2, RT, 1 h, 89%; b) CBr4, PPh3/CH2Cl2, 08C!RT,
2 h, 96%; c) nBuLi/THF, ꢀ788C!RT, 1 h, 97%; d) 14, nBuLi, HMPA/
THF, RT, 2.5 h, 78%; e) BzCl, DMAP/py, RT, 2 h, 99%; f) i) H2,
Pd(OH)2/EtOH, RT, 1.5 h; ii) Dess–Martin periodinane, NaHCO3/
CH2Cl2, RT, 1 h, 87% (2 steps); g) NaClO2, NaH2PO4, 2-methyl-2-
butene, tBuOH/THF/H2O (5:4:1), 308C, 15 min, quant.; h) 39, ED-
CI·HCl/CH2Cl2, RT, 18 h, 68%; i) TIPSCl, imidazole/DMF, RT, 2.5 h,
83%; j) Bz2O, DMAP/py, 17 h, 99%; k) TBAF, AcOH/THF, RT, 24 h,
90%. HMPA=hexamethylphosphoric triamide, EDCI=1-ethyl-3-(3-di-
methylaminopropyl)carbodiimide, TIPS=triisopropylsilyl, TBAF=tetra-
n-butylammonium fluoride.
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H. Ando, M. Kiso et al.
out further purification. TLC analysis was performed on Merck TLC
plates (silica gel 60F254 on glass). Compounds were visualized either by
exposure to UV light (254 nm) or by spraying with 10% H2SO4 solution
in EtOH, 20% phosphomolybdic acid solution in EtOH, or ninhydrin re-
agent, followed by heating. Flash column chromatography on silica gel
(Fuji Silysia Co., 80 mesh and 300 mesh) or Sephadex (Pharmacia LH-
20) was performed with the solvent systems (v/v) specified. Evaporation
and concentration were conducted in vacuo.
aqueous NaHCO3 solution at 08C, filtered through Celite, and the filter
bed was washed with EtOAc. The combined filtrate and washings were
extracted with EtOAc, and the organic layer was washed with saturated
aqueous Na2S2O3 and brine, dried over Na2SO4, and concentrated. The
residue was purified by column chromatography on silica gel (CHCl3/
EtOAc 8:1!7:1) to give 21 (3.20 g, 75%) and 22 (541 mg, 13%). 21:
[a]D =ꢀ1.18 (c=1.4, CHCl3); 1H NMR (500 MHz, CDCl3): d=7.33–6.82
(m, 14H; 3 Ar), 6.17 (d, 1H, JNH,5 =10.0 Hz; NH), 5.41 (m, 1H; H-8b),
5.26 (dd, 1H, J6,7 =2.2, J7,8 =9.3 Hz; H-7b), 4.99 (m, 1H; H-4b), 4.89–4.64
2-(Trimethylsilyl)ethyl 3,4-di-O-benzyl-2-O-p-methoxybenzyl-b-d-gluco-
pyranoside (8): NaH (60% dispersion in mineral oil; 971 mg, 24.3 mmol)
was added to a solution of compound 17 (5.57 g, 12.1 mmol) in DMF
(121 mL) and the mixture was stirred for 40 min at 08C. p-Methoxyben-
zyl chloride (1.82 mL, 13.4 mmol) was then added and stirring was con-
tinued for 3 h at room temperature. Completion of the reaction was con-
firmed by TLC (hexane/EtOAc 3:1). The reaction mixture was then
quenched with EtOH and saturated aqueous NH4Cl solution at 08C, and
extracted with EtOAc. The organic layer was washed sequentially with
water and brine, dried over Na2SO4, and concentrated. The residue was
roughly purified by column chromatography on silica gel (hexane/EtOAc
12:1) to give crude 18 (7.37 g). The crude material was dried for 21 h and
then dissolved in toluene (160 mL), and the resulting solution was cooled
to 08C. DIBAL-H (1.5m solution in toluene; 20.2 mL, 30.3 mmol) was
added and the resulting mixture was stirred for 18 h at room tempera-
ture. Completion of the reaction was confirmed by TLC (hexane/EtOAc
3:1). After the addition of Rochelle salt {KOOC-CH(OH)-CH(OH)-
COONa}, the suspension was extracted with EtOAc. The organic layer
was washed with brine, dried over Na2SO4, and concentrated. The residue
was purified by column chromatography on silica gel (hexane/EtOAc
5:1) to give 8 (5.21 g, 74%). [a]D =+14.08 (c=3.1, CHCl3); 1H NMR
(500 MHz, CDCl3): d=7.50–6.82 (m, 14H; 3 Ar), 4.94–4.62 (6 d, 6H;
ArCH2), 4.43 (d, 1H, J1,2 =7.8 Hz; H-1), 3.99 (m, 1H; TMSCH2CH2),
3.87 (m, 1H; H-6), 3.79 (s, 3H; OMe), 3.71 (m, 1H; H-6’), 3.63 (m, 2H;
H-3, TMSCH2CH2), 3.55 (app t, 1H, J3,4 =9.3, J4,5 =9.5 Hz; H-4), 3.39
(6 d, 6H; ArCH2), 4.34 (d, 1H, J1,2 =8.1 Hz; H-1a), 4.23 (dd, 1H, J5,6
=
10.7 Hz; H-6b), 4.17 (m, 2H; H-4a, H-9b), 3.95 (m, 3H; H-5b, H-9’b,
TMSCH2CH2), 3.79 (s, 3H; OMe), 3.76 (s, 3H; COOMe), 3.59 (m, 4H;
H-3a, H-6a, H-6’a, TMSCH2CH2), 3.38 (m, 2H; H-2a, H-5a), 2.72 (dd,
1H, Jgem =12.7, J3eq,4 =4.6 Hz; H-3beq), 2.14–1.91 (m, 13H; H-3bax, 4 Ac),
1.04 ppm (m, 2H; TMSCH2CH2); 13C NMR (100 MHz, CDCl3): d=170.9,
170.5, 170.1, 169.8, 167.7, 159.1, 157.7, 157.3, 138.7, 138.4, 130.7, 129.7,
128.3, 128.2, 127.9, 127.7, 127.5, 116.8, 114.0, 113.7, 103.1, 98.8, 84.5, 81.8,
77.4, 75.6, 74.8, 74.3, 73.7, 71.5, 68.5, 67.3, 66.9, 63.9, 61.9, 55.2, 52.6, 50.1,
37.9, 29.6, 20.6, 20.5, 20.3, 18.5, ꢀ1.5 ppm; HRMS: m/z: calcd for
C53H68F3NO19Si+Na+: 1130.4005 [M+Na]+; found: 1130.4020; 22: [a]D =
+1.58 (c=1.3, CHCl3); 1H NMR (500 MHz, CDCl3): d=7.33–6.84 (m,
14H; 3 Ar), 6.73 (d, 1H, JNH,5 =10.3 Hz; NH), 5.41 (m, 1H; H-4b), 5.36
(dd, 1H, J6,7 =2.3, J7,8 =4.0 Hz; H-7b), 5.29 (m, 1H; H-8b), 4.94–4.66 (m,
7H; H-9b, ArCH2), 4.59 (dd, 1H, J5,6 =10.3 Hz; H-6b), 4.45 (d, 1H, J1,2
=
8.0 Hz; H-1a), 4.14 (m, 2H; H-5b, H-9’b), 4.04 (m, 1H; TMSCH2CH2),
3.75 (m, 10H; H-4a, H-6a, H-6’a, COOMe, OMe, TMSCH2CH2), 3.61
(app t, J2,3 =9.2, J3,4 =9.7 Hz; H-3a), 3.45 (m, 2H; H-2a, H-5a), 2.43 (dd,
1H, Jgem =12.6, J3eq,4 =4.6 Hz; H-3beq), 2.18–2.00 (m, 12H; 4Ac), 1.96
(app t, 1H; H-3bax), 1.07 ppm (m, 2H; TMSCH2CH2); 13C NMR
(125 MHz, CDCl3): d=170.6, 170.5, 169.9, 169.7, 166.8, 159.2, 157.8,
157.6, 138.5, 138.2, 130.5, 129.8, 128.4, 128.3, 127.8, 127.8, 127.7, 127.6,
116.6, 114.3, 113.8, 103.2, 97.5, 84.1, 82.0, 76.4, 75.7, 75.0, 74.8, 73.5, 71.3,
70.2, 68.6, 68.3, 68.0, 62.4, 60.9, 55.2, 52.7, 49.6, 37.1, 20.7, 20.6, 20.6, 18.6,
ꢀ1.6 ppm; HRMS: m/z: calcd for C53H68F3NO19Si+Na+: 1130.4005
[M+Na]+; found: 1130.4004.
(dd, 1H,
J2,3 =9.0 Hz; H-2), 3.35 (m, 1H; H-5), 1.05 ppm (m, 2H;
TMSCH2CH2); 13C NMR (100 MHz, CDCl3): d=159.2, 138.6, 138.0,
130.6, 129.8, 128.5, 128.3, 128.1, 127.9, 127.8, 127.6, 113.8, 103.3, 84.5,
82.1, 77.2, 75.6, 75.1, 74.9, 74.5, 67.8, 62.1, 55.2, 18.7, 14.2, ꢀ1.4 ppm;
HRMS: m/z: calcd for C33H44O7Si+Na+: 603.2754 [M+Na]+; found:
603.2774.
2-(Trimethylsilyl)ethyl (methyl 3,5-dideoxy-5-trifluoroacetamido-d-glyc-
ero-a-d-galacto-2-nonulopyranosylonate)-(2!6)-3,4-di-O-benzyl-2-O-p-
methoxybenzyl-b-d-glucopyranoside (23): A 28% solution of sodium
methoxide (59 mg, 306 mmol) in MeOH was added to a solution of com-
pound 21 (2.76 g, 2.49 mmol) in MeOH (36 mL). The mixture was stirred
for 2 h at room temperature, and the progress of the reaction was moni-
tored by TLC (CHCl3/MeOH 10:1). The reaction mixture was then neu-
tralized with Dowex-50 (H+), filtered, and concentrated. The residue was
purified by column chromatography on silica gel (CHCl3/MeOH 38:1!
20:1) to give 23 (2.19 g, 94%). [a]D =ꢀ0.28 (c=1.0, CHCl3/MeOH 1:1);
1H NMR (500 MHz, CD3OD): d=7.31–6.80 (m, 14H; 3 Ar), 4.86–4.61 (6
d, 6H; ArCH2), 4.39 (d, 1H, J1,2 =7.8 Hz; H-1a), 3.99 (m, 2H; H-5b,
TMSCH2CH2), 3.79 (m, 12H; H-6a, H-4b, H-6b, H-7b, H-8b, H-9b,
COOMe, OMe), 3.63 (m, 2H; H-9’b, TMSCH2CH2), 3.57 (app t, 1H,
2-(Trimethylsilyl)ethyl 6-O-acetyl-3,4-di-O-benzyl-2-O-p-methoxybenzyl-
b-d-glucopyranoside (8’): Acetic anhydride (500 mL) was added to a solu-
tion of compound 8 (124 mg, 214 mmol) in pyridine (800 mL). The mixture
was stirred for 15 h at room temperature. Completion of the reaction was
confirmed by TLC (hexane/EtOAc 4:1). The reaction mixture was then
concentrated and the residual solvent was removed by co-evaporation
with toluene. The residue was purified by column chromatography on
silica gel (hexane/EtOAc 7:1) to give 8’ (129 mg, 97%). [a]D =ꢀ20.08
(c=1.2, CHCl3); 1H NMR (500 MHz, CDCl3): d=7.34–6.82 (m, 14H;
3Ar), 4.97–4.54 (6d, 6H; ArCH2), 4.40 (d, 1H, J1,2 =8.0 Hz; H-1), 4.33
(d, 1H, Jgem =12.0 Hz; H-6), 4.24 (dd, 1H, J5,6’ =4.6 Hz; H-6’), 3.99 (m,
1H; TMSCH2CH2), 3.76 (s, 3H; OMe), 3.63 (m, 2H; H-3, TMSCH2CH2),
3.51 (m, 2H; H-4, H-5), 3.43 (app t, 1H, J2,3 =8.6 Hz; H-2), 2.02 (s, 3H;
Ac), 1.07 ppm (m, 2H; TMSCH2CH2); 13C NMR (100 MHz, CDCl3): d=
170.6, 159.1, 138.4, 137.7, 130.5, 129.7, 128.4, 128.3, 128.0, 127.8, 127.7,
127.5, 113.7, 103.1, 84.6, 81.8, 77.4, 75.5, 74.9, 74.3, 72.6, 67.5, 63.1, 55.1,
20.7, 18.4, ꢀ1.5 ppm; HRMS: m/z: calcd for C35H46O8Si+Na+: 645.2860
[M+Na]+; found: 645.2884.
J
2,3 =9.0, J3,4 =8.8 Hz; H-3a), 3.50 (m, 2H; H-4a, H-6’a), 3.40 (m, 1H; H-
5a), 3.29 (m, 1H; H-2a), 2.75 (dd, 1H, Jgem =12.9, J3eq,4 =4.6 Hz; H-3beq),
1.80 (app t, 1H; H-3bax), 1.02 ppm (m, 2H; TMSCH2CH2); 13C NMR
(100 MHz, CD3OD): d=170.5, 160.7, 140.0, 139.7, 132.0, 130.7, 129.3,
129.1, 128.8, 128.7, 128.5, 114.6, 104.2, 100.3, 85.8, 83.1, 78.8, 76.5, 75.8,
75.3, 75.1, 73.9, 72.6, 70.0, 68.4, 64.5, 64.3, 55.7, 53.9, 53.4, 41.7, 19.4,
ꢀ1.3 ppm; HRMS: m/z: calcd for C45H60F3NO15Si+Na+: 962.3582
[M+Na]+; found: 962.3580.
2-(Trimethylsilyl)ethyl (methyl 3,5-dideoxy-8,9-O-isopropylidene-5-tri-
fluoroacetamido-d-glycero-a-d-galacto-2-nonulopyranosylonate)-(2!6)-
3,4-di-O-benzyl-2-O-p-methoxybenzyl-b-d-glucopyranoside (24): 2,2-Di-
methoxypropane (193 mL, 1.57 mmol) and (ꢁ)-10-camphorsulfonic acid
(12 mg, 52 mmol) were added to a solution of compound 23 (981 mg,
1.04 mmol) in MeCN (20.8 mL). The mixture was stirred for 2 h at room
temperature, and the progress of the reaction was monitored by TLC
(hexane/EtOAc 1:1). The reaction mixture was then made alkaline to
pH 9 with triethylamine and the volatiles were co-evaporated with tolu-
ene. The residue was subjected to column chromatography on silica gel
(hexane/EtOAc 7:3) to give 24 (982 mg, 96%). [a]D =+0.38 (c=1.5,
CHCl3); 1H NMR (500 MHz, CD3OD): d=7.33–6.81 (m, 14H; 3Ar),
2-(Trimethylsilyl)ethyl (methyl 4,7,8,9-tetra-O-acetyl-3,5-dideoxy-5-tri-
fluoroacetamido-d-glycero-a-d-galacto-2-nonulopyranosylonate)-(2!6)-
3,4-di-O-benzyl-2-O-p-methoxybenzyl-b-d-glucopyranoside (21) and b-
isomer (22): 3 ꢂ molecular sieves (8.0 g) were added to a solution of
compounds 7 (3.05 g, 4.78 mmol) and 8 (2.22 g, 3.82 mmol) in MeCN
(43 mL)/CH2Cl2 (3.3 mL). The suspension was stirred for 1 h at room
temperature and then cooled to ꢀ308C, whereupon N-iodosuccinimide
(NIS) (1.70 g, 7.17 mmol) and trifluoromethanesulfonic acid (TfOH)
(42 mL, 478 mmol) were added. Stirring was continued for 3.5 h, after
which TLC analysis (PhMe/acetone 4:1) indicated completion of the re-
action. The reaction mixture was made alkaline to pH 8 with saturated
4642
www.chemeurj.org
ꢀ 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Chem. Eur. J. 2009, 15, 4637 – 4648

Synthesis of Ganglioside HLG-2
FULL PAPER
4.88–4.62 (6d, 6H; ArCH2), 4.40 (d, 1H, J1,2 =7.8 Hz; H-1a), 4.21 (q, 1H;
H-6b), 3.97 (m, 5H; H-6a, H-5b, H-8b, TMSCH2CH2), 3.78 (m, 9H; H-
4b, H-9b, H-9’b, COOMe, OMe), 3.65 (m, 1H; TMSCH2CH2), 3.59 (app
t, 1H, J2,3 =9.0, J3,4 =8.8 Hz; H-3a), 3.53 (app d, 1H; H-7b), 3.49 (app t,
1H, J4,5 =9.8 Hz; H-4a), 3.42 (m, 1H; H-6’a), 3.31 (m, 2H; H-2a, H-5a),
2.72 (dd, 1H, Jgem =12.7, J3eq,4 =4.6 Hz; H-3beq), 1.77 (app t, 1H; H-3bax),
1.34–1.29 (2s, 6H; 2 Me), 1.02 ppm (m, 2H; TMSCH2CH2); 13C NMR
(100 MHz, CDCl3): d=168.4, 159.2, 158.7, 158.3, 138.5, 138.1, 130.6,
129.7, 128.4, 128.3, 127.9, 127.8, 127.6, 117.0, 114.1, 113.8, 108.9, 103.1,
99.0, 84.6, 81.9, 77.6, 75.6, 75.5, 74.8, 74.4, 73.9, 72.6, 69.9, 67.7, 67.1, 66.4,
63.6, 55.2, 53.9, 52.5, 39.9, 26.7, 25.5, 18.5, ꢀ1.5 ppm; HRMS: m/z: calcd
for C48H64F3NO15Si+Na+: 1002.3895 [M+Na]+; found: 1002.3837.
cooled to ꢀ408C, whereupon NIS (1.33 g, 5.61 mmol) and TfOH (33 mL,
374 mmol) were added. Stirring was continued for 16 h, when completion
of the reaction was indicated by TLC (PhMe/EtOAc 2:3). The reaction
mixture was made alkaline to pH 8 with saturated aqueous NaHCO3 so-
lution at 08C, filtered through Celite, and the removed molecular sieves
were washed with EtOAc. The combined filtrate and washings were ex-
tracted with EtOAc, and the organic layer was washed with saturated
aqueous Na2S2O3 solution and brine, dried over Na2SO4, and concentrat-
ed. The residue was purified by column chromatography on silica gel
(PhMe/EtOAc 2:1!4:3) to give 26 (1.65 g, 60%) and 27 (235 mg, 9%).
26: [a]D =ꢀ3.08 (c=1.6, CHCl3); 1H NMR (500 MHz, CDCl3): d=7.37–
6.81 (m, 14H; 3 Ar), 6.89 (d, 1H, JNH,5 =5.9 Hz; NH-b), 5.43 (m, 1H; H-
8c), 5.28 (dd, 1H, J6,7 =2.0, J7,8 =9.8 Hz; H-7c), 4.97–4.50 (m, 10H; H-4c,
2-(Trimethylsilyl)ethyl (methyl 4,7-di-O-acetyl-3,5-dideoxy-8,9-O-isopro-
pylidene-5-trifluoroacetamido-d-glycero-a-d-galacto-2-nonulopyranosyl-
onate)-(2!6)-3,4-di-O-benzyl-2-O-p-methoxybenzyl-b-d-glucopyranoside
(24’): Acetic anhydride (500 mL) was added to a solution of compound 24
(54.0 mg, 55.1 mmol) in pyridine (1.0 mL) and the mixture was stirred for
2 h at room temperature. Completion of the reaction was confirmed by
TLC (hexane/EtOAc 1:1), whereupon the reaction mixture was concen-
trated and residual volatiles were removed by co-evaporation with tolu-
ene. The residue was purified by column chromatography on silica gel
(CHCl3/EtOAc 3:1) to give 24’ (56.1 mg, 96%). [a]D =2.48 (c=1.8,
CHCl3); 1H NMR (600 MHz, CDCl3): d=7.34–6.82 (m, 14H; 3Ar), 6.23
(brd, 1H; NH), 5.26 (dd, 1H, J6,7 =2.1, J7,8 =4.8 Hz; H-7b), 5.09 (m, 1H;
H-4b), 4.91–4.64 (6 d, 6H; ArCH2), 4.34 (m, 2H; H-1a, H-8b), 3.95 (m,
6H; H-6a, H-5b, H-6b, H-9b, H-9’b, TMSCH2CH2), 3.78 (2s, 6H;
COOMe, OMe), 3.59 (m, 3H; H-3a, H-4a, TMSCH2CH2), 3.37 (m, 2H;
H-2a, H-5a), 2.74 (dd, 1H, Jgem =13.1, J3eq,4 =4.8 Hz; H-3beq), 2.02–1.99
(2s, 6H; 2 Ac), 1.90 (app t, 1H; H-3bax), 1.34–1.32 (2s, 6H; 2 Me),
1.04 ppm (m, 2H; TMSCH2CH2); 13C NMR (125 MHz, CDCl3): d=170.8,
170.2, 167.6, 159.2, 138.6, 138.2, 138.1, 130.6, 129.8, 128.5, 128.4, 128.3,
128.0, 127.9, 127.8, 127.6, 113.7, 108.7, 103.1, 99.1, 84.6, 81.8, 77.4, 75.6,
75.3, 75.1, 74.9, 74.8, 74.4, 73.8, 73.7, 73.4, 72.6, 69.6, 68.7, 68.5, 68.2, 67.5,
67.4, 66.6, 65.6, 63.6, 63.5, 55.2, 52.7, 52.6, 50.6, 37.5, 26.8, 26.4, 25.5, 25.4,
20.7, 20.6, 18.5, ꢀ1.4 ppm; HRMS: m/z: calcd for C52H68F3NO17Si+Na+:
1086.4106 [M+Na]+; found: 1086.4106.
NH-c, Cl3CCH2, ArCH2), 4.39 (m, 2H; H-1a, H-6b), 4.32 (dd, 1H, J5,6
=
10.7, J6,7 =2.0 Hz; H-6c), 4.26 (dd, 1H, Jgem =12.2, J8,9 =2.4 Hz; H-9c),
4.15 (m, 2H; H-6a, H-9b), 4.03 (m, 4H; H-6’a, H-5b, H-9’b,
TMSCH2CH2), 3.89 (m, 3H; H-4b, H-8b, H-9’c), 3.76 (m, 8H; H-7b, H-
5c, COOMe, OMe), 3.58 (m, 4H; H-3a, H-4a, H-5a, TMSCH2CH2), 3.40
(app t, 1H, J1,2 =8.1, J2,3 =8.6 Hz; H-2a), 2.61 (dd, 1H, Jgem =12.8, J3eq,4
=
4.8 Hz; H-3ceq), 2.30 (dd, 1H, Jgem =10.6, J3ax,4 =3.4 Hz; H-3bax), 2.19–2.01
(m, 13H; H-3beq, 4 Ac), 1.95 (app t, 1H; H-3cax), 1.43–1.38 (2s, 6H; 2
Me), 1.06 ppm (m, 2H; TMSCH2CH2); 13C NMR (100 MHz, CDCl3): d=
171.6, 170.4, 170.3, 170.2, 169.2, 168.1, 159.1, 154.1, 138.7, 138.5, 130.8,
129.8, 128.3, 128.2, 127.9, 127.8, 127.5, 127.4, 113.7, 108.9, 103.1, 99.5,
95.6, 95.2, 84.7, 81.9, 78.1, 77.8, 75.6, 75.0, 74.6, 74.5, 74.3, 74.1, 72.7, 72.2,
70.9, 67.9, 67.4, 67.3, 66.8, 65.2, 63.5, 63.2, 55.2, 53.2, 52.8, 51.2, 38.0, 37.7,
29.6, 26.6, 25.7, 20.9, 20.8, 20.7, 20.6, 18.5, ꢀ1.5 ppm; HRMS: m/z: calcd
for C66H87Cl3N2O26Si+Na+: 1479.4280 [M+Na]+; found: 1479.4258. 27:
1
[a]D =ꢀ12.58 (c=0.9, CHCl3); H NMR (600 MHz, CDCl3): d=7.32–6.82
(m, 14H; 3 Ar), 6.83 (brs, 1H; NH-b), 5.42 (m, 1H; H-7c), 5.17 (m, 1H;
H-4c), 5.10 (d, 1H, JNH,5 =9.6 Hz; NH-c), 5.02 (m, 1H; H-8c), 4.90–4.47
(m, 9H; H-9c, Cl3CCH2, ArCH2), 4.43 (m, 1H; H-9b), 4.38 (d, 1H, J1,2
=
8.2 Hz; H-1a), 4.24 (m, 2H; H-4b, H-8b), 4.01 (m, 5H; H-6a, H-5b, H-
9’b, H-6c, TMSCH2CH2), 3.89 (m, 2H; H-7b, H-9c), 3.79 (m, 8H; H-6b,
H-5c, COOMe, OMe), 3.61 (m, 3H; H-3a, H-4a, TMSCH2CH2), 3.53 (m,
2H; H-5a, H-6’a), 3.39 (app t, 1H, J2,3 =8.3 Hz; H-2a), 3.15 (d, 1H; 7b-
OH), 2.49 (dd, 1H, Jgem =13.0, J3eq,4 =4.8 Hz; H-3ceq), 2.37 (app t, 1H; H-
3bax), 2.20 (dd, 1H, Jgem =13.8, J3eq,4 =4.8 Hz; H-3beq), 2.15–2.00 (4s, 12H;
4 Ac), 1.91 (app t, 1H; H-3cax), 1.38–1.28 (2s, 6H; 2 Me), 1.05 ppm (m,
2H; TMSCH2CH2); 13C NMR (100 MHz, CDCl3): d=170.9, 170.6, 170.1,
169.9, 169.2, 167.4, 159.1, 154.2, 138.8, 138.6, 130.8, 129.7, 128.3, 128.2,
127.8, 127.5, 127.4, 113.7, 109.2, 103.1, 99.5, 95.5, 95.3, 84.8, 81.9, 78.3,
77.6, 77.2, 75.6, 74.6, 74.5, 74.3, 74.2, 72.8, 71.7, 70.7, 70.2, 68.6, 67.9, 67.5,
66.6, 63.3, 62.1, 55.2, 53.3, 51.7, 51.1, 38.8, 36.9, 29.7, 26.7, 25.2, 20.9, 20.8,
20.7, 20.7, 18.6, ꢀ1.4 ppm; HRMS: m/z: calcd for C66H87Cl3N2O26Si+Na+:
1479.4280 [M+Na]+; found: 1479.4280.
2-(Trimethylsilyl)ethyl
(5-amino-3,5-dideoxy-8,9-O-isopropylidene-d-
glycero-a-d-galacto-2-nonulopyranosylono-1,5-lactam)-(2!6)-3,4-di-O-
benzyl-2-O-p-methoxybenzyl-b-d-glucopyranoside (25): Drierite (6.3 g)
was added to a solution of compound 24 (2.09 g, 2.13 mmol) in MeOH
(222 mL) and the suspension was stirred for 1 h at room temperature. A
28% solution of sodium methoxide in MeOH (1.27 mL, 5.33 mmol) was
added and the resulting mixture was stirred for 92 h under reflux. Com-
pletion of the reaction was confirmed by TLC (CHCl3/MeOH 10:1),
whereupon the reaction mixture was neutralized with Dowex-50 (H+)
and filtered through Celite. The combined filtrate and washings were
concentrated. The residue was subjected to column chromatography on
silica gel (CHCl3/MeOH 60:1!40:1) to give 25 (1.82 g, 95%). [a]D =
ꢀ23.08 (c=1.0, CHCl3); 1H NMR (500 MHz, CDCl3): d=7.33–6.81 (m,
14H; 3 Ar), 4.91–4.64 (m, 7H; H-5b, ArCH2), 4.40 (d, 1H, J1,2 =7.8 Hz;
H-1a), 4.32 (brs, 1H; H-8b), 4.28 (app d, 1H; H-9b), 4.10 (m, 1H; H-4b),
4.00 (m, 4H; H-6a, H-6b, H-9’b, TMSCH2CH2), 3.79 (s, 3H; OMe), 3.60
(m, 6H; H-3a, H-4a, H-5a, H-6’a, H-7b, TMSCH2CH2), 3.37 (app t, 1H;
2-(Trimethylsilyl)ethyl [methyl 4,7,8,9-tetra-O-acetyl-3,5-dideoxy-5-(2,2,2-
trichloroethoxycarbamoyl)-d-glycero-a-d-galacto-2-nonulopyranosylo-
nate]-(2!4)-(5-amino-7,8,9-tri-O-acetyl-3,5-dideoxy-d-glycero-a-d-galac-
to-2-nonulopyranosylono-1,5-lactam)-(2!6)-3,4-di-O-benzyl-2-O-p-me-
thoxybenzyl-b-d-glucopyranoside (28): 80% aqueous AcOH (3.84 mL)
was added to a flask containing compound 26 (225 mg, 154 mmol). The
mixture was stirred for 17 h at 458C, as the progress of the reaction was
monitored by TLC (CHCl3/MeOH 15:1). The reaction mixture was then
concentrated, the remaining volatiles were co-evaporated with toluene,
and the residue was exposed to high vacuum for 9 h. The crude material
was redissolved in pyridine (2.24 mL) and then acetic anhydride (873 mL)
was added to the solution at 08C. The mixture was stirred for 6 h at
room temperature, when completion of the reaction was confirmed by
TLC (CHCl3/MeOH 25:1). After quenching with EtOH, the mixture was
concentrated and the residual volatiles were co-evaporated with toluene.
The residue was redissolved in EtOAc, and this solution was washed with
2m aqueous HCl, water, saturated aqueous NaHCO3 solution, and brine,
dried (Na2SO4), and concentrated. The residue was purified by column
chromatography on silica gel (hexane/EtOAc 4:3) to give 28 (196 mg,
82%). [a]D =ꢀ2.58 (c=1.7, CHCl3); 1H NMR (500 MHz, CDCl3): d=
7.31–6.81 (m, 14H; 3 Ar), 6.93 (d, 1H, JNH,5 =5.9 Hz; NH-b), 5.84 (dd,
1H, J6,7 =2.4, J7,8 =9.4 Hz; H-7b), 5.46 (m, 2H; H-8b, H-8c), 5.27 (d, 1H,
H-2a), 2.43 (app t, 1H, Jgem =14.2 Hz; H-3bax), 1.97 (dd, 1H, J3eq,4
=
4.8 Hz; H-3beq), 1.36 (2s, 6H; 2 Me), 1.05 ppm (t, 2H; TMSCH2CH2);
13C NMR (100 MHz, CDCl3): d=170.4, 159.2, 138.5, 138.2, 130.5, 129.7,
128.3, 128.3, 127.9, 127.8, 127.6, 127.5, 113.7, 109.6, 103.2, 95.9, 84.6, 82.0,
77.6, 75.6, 75.3, 74.7, 74.5, 74.4, 71.0, 68.1, 67.3, 67.1, 63.4, 55.2, 54.0, 39.1,
29.6, 26.8, 25.2, 18.5, ꢀ1.5 ppm; HRMS: m/z: calcd for C45H61NO13Si+
Na+: 874.3810 [M+Na]+; found: 874.3811.
2-(Trimethylsilyl)ethyl [methyl 4,7,8,9-tetra-O-acetyl-3,5-dideoxy-5-(2,2,2-
trichloroethoxycarbamoyl)-d-glycero-a-d-galacto-2-nonulopyranosylo-
nate]-(2!4)-(5-amino-3,5-dideoxy-8,9-O-isopropylidene-d-glycero-a-d-
galacto-2-nonulopyranosylono-1,5-lactam)-(2!6)-3,4-di-O-benzyl-2-O-p-
methoxybenzyl-b-d-glucopyranoside (26) and b-isomer (27): 3 ꢂ molecu-
lar sieves (4.6 g) were added to a solution of compounds 5 (2.69 g,
3.74 mmol) and 25 (1.60 g, 1.87 mmol) in EtCN (34 mL)/CH2Cl2
(3.8 mL). The suspension was stirred for 1 h at room temperature, then
J
7,8 =9.8 Hz; H-7c), 4.99 (m, 1H; H-4c), 4.90–4.53 (m, 9H; NH-c,
Chem. Eur. J. 2009, 15, 4637 – 4648
ꢀ 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.chemeurj.org
4643

H. Ando, M. Kiso et al.
Cl3CCH2, ArCH2), 4.32 (m, 6H; H-1a, H-6a, H-6b, H-9b, H-6c, H-9c),
4.15 (dd, 1H, Jgem =11.4, J8,9 =5.3 Hz; H-9’c), 3.91 (m, 12H; H-6’a, H-4b,
H-5b, H-9’b, H-5c, COOMe, OMe, TMSCH2CH2), 3.56 (m, 4H; H-3a, H-
4a, H-5a, TMSCH2CH2), 3.39 (app t, 1H, J1,2 =7.8, J2,3 =9.0 Hz; H-2a),
2.50 (dd, 1H, Jgem =12.7, J3eq,4 =4.6 Hz; H-3ceq), 2.24–1.89 (m, 24H; H-
purified by column chromatography on silica gel (hexane/EtOAc 3:2!
1:2) to give 30 (23.7 mg, 93%). [a]D =ꢀ5.78 (c=3.0, CHCl3); 1H NMR
(600 MHz, CDCl3): d=8.17–7.24 (m, 20H; 4 Ph), 6.09 (dd, 1H, J6,7 =2.5,
J
7,8 =9.3 Hz; H-7b), 5.71 (m, 1H; H-8c), 5.54 (d, 1H, J7,8 =10.3 Hz; H-7c),
5.46 (m, 4H; H-8b, H-4c, PhCH2), 5.39 (app t, 1H, J1,2 =8.2, J2,3 =9.0 Hz;
H-2a), 5.29 (d, 1H, JNH,5 =8.3 Hz; NH-c), 5.16 (s, 1H; H-5b), 5.11–4.64
3bax, H-3beq, H-3cax,
7 Ac), 1.05 ppm (app t, 2H; TMSCH2CH2);
13C NMR (100 MHz, CDCl3): d=171.5, 170.6, 170.5, 170.3, 169.9, 169.8,
169.2, 169.1, 168.7, 159.1, 157.6, 153.8, 139.5, 138.7, 138.6, 132.9, 130.8,
129.8, 129.6, 128.3, 128.2, 127.8, 127.8, 127.7, 127.4, 113.7, 110.5, 103.0,
102.8, 100.3, 95.7, 95.3, 85.7, 84.6, 82.0, 81.9, 78.2, 76.2, 75.5, 74.4, 74.3,
74.0, 73.4, 72.8, 72.6, 71.9, 68.8, 67.7, 67.5, 67.3, 66.9, 63.6, 63.4, 60.9, 56.3,
55.2, 53.1, 51.6, 50.5, 37.1, 36.3, 20.9, 20.8, 20.8, 20.7, 20.5, 20.5, 18.5,
ꢀ1.4 ppm; HRMS: m/z: calcd for C69H89Cl3N2O29Si+Na+: 1565.4284
[M+Na]+; found: 1565.4272.
(m, 8H; H-1a, H-6b, Cl3CCH2, PhCH2), 4.51 (dd, 1H, Jgem =12.4, J8,9
2.8 Hz; H-9c), 4.42 (m, 3H; H-4b, H-6b, H-9b), 4.35 (d, 1H, Jgem
=
=
10.3 Hz; H-6a), 4.27 (dd, 1H, Jgem =11.4, J8,9 =4.5 Hz; H-9’b), 4.19 (d,
1H; H-9’c), 4.14 (m, 1H; TMSCH2CH2), 3.97 (m, 5H; H-3a, H-6’a,
COOMe), 3.84 (m, 2H; H-4a, H-5a), 3.68 (m, 2H; H-5c, TMSCH2CH2),
2.75 (dd, 1H, Jgem =13.0, J3eq,4 =4.8 Hz; H-3ceq), 2.44 (m, 2H; H-3bax, H-
3beq), 2.27–1.89 (7s, 21H; 7 Ac), 1.71 (app t, 1H, J3ax,4 =13.0 Hz; H-3cax),
1.00 ppm (app t, 2H; TMSCH2CH2); 13C NMR (150 MHz, CDCl3): d=
170.8, 170.7, 170.2, 169.9, 169.7, 169.6, 169.5, 168.3, 165.1, 164.3, 153.6,
151.8, 138.3, 137.8, 135.1, 132.9, 130.2, 129.7, 128.5, 128.3, 128.2, 128.2,
128.1, 128.0, 127.8, 127.7, 127.5, 100.3, 98.9, 96.0, 95.6, 82.8, 78.3, 75.4,
74.9, 74.5, 74.2, 73.8, 71.6, 71.2, 69.4, 69.3, 69.2, 67.1, 67.0, 66.9, 63.5, 62.1,
60.7, 53.3, 53.1, 51.0, 37.5, 35.9, 29.6, 20.9, 20.8, 20.8, 20.6, 20.5, 20.4, 17.8,
ꢀ1.5 ppm; HRMS: m/z: calcd for C76H91Cl3N2O31Si+Na+: 1683.4338
[M+Na]+; found: 1683.4338.
2-(Trimethylsilyl)ethyl [methyl 4,7,8,9-tetra-O-acetyl-3,5-dideoxy-5-(2,2,2-
trichloroethoxycarbamoyl)-d-glycero-a-d-galacto-2-nonulopyranosylo-
nate]-(2!4)-(7,8,9-tri-O-acetyl-5-benzyloxycarbamoyl-3,5-dideoxy-d-
glycero-a-d-galacto-2-nonulopyranosylono-1,5-lactam)-(2!6)-3,4-di-O-
benzyl-2-O-p-methoxybenzyl-b-d-glucopyranoside (29): N-Benzyloxycar-
bonyl succinimide (146 mg, 574 mmol) and 4-dimethylaminopyridine
(DMAP) (7.0 mg, 57.4 mmol) were added to a solution of compound 28
(222 mg, 143 mmol) in pyridine (3.0 mL). The mixture was stirred for 48 h
at room temperature with monitoring of the reaction by TLC (hexane/
EtOAc 2:3). After quenching with EtOH, the mixture was concentrated
and the residual volatiles were co-evaporated with toluene. The residue
was redissolved in EtOAc, and this solution washed with 2m aqueous
HCl, water, saturated aqueous NaHCO3 solution, and brine, dried
(Na2SO4), and concentrated. The residue was purified by column chroma-
tography, first on silica gel (hexane/EtOAc 2:1) and then on Sephadex
LH-20 (CHCl3/MeOH 1:1) to give 29 (191 mg, 79%). [a]D =ꢀ0.68 (c=
1.1, CHCl3); 1H NMR (500 MHz, CDCl3): d=7.45–6.81 (m, 19H; 4 Ar),
5.92 (dd, 1H, J6,7 =2.3, J7,8 =9.7 Hz; H-7b), 5.55 (m, 1H; H-8c), 5.38 (d,
1H, J7,8 =9.7 Hz; H-7c), 5.30 (m, 4H; H-8b, H-4c, ArCH2), 5.14 (d, 1H,
2-(Trimethylsilyl)ethyl (methyl 4,7,8,9-tetra-O-acetyl-5-benzyloxyacetami-
do-3,5-dideoxy-d-glycero-a-d-galacto-2-nonulopyranosylonate)-(2!4)-
(7,8,9-tri-O-acetyl-5-benzyloxycarbamoyl-3,5-dideoxy-d-glycero-a-d-gal-
acto-2-nonulopyranosylono-1,5-lactam)-(2!6)-2-O-benzoyl-3,4-di-O-
benzyl-b-d-glucopyranoside (31): Zinc-copper couple (7.44 g) was added
to a solution of compound 30 (496 mg, 298 mmol) in acetic acid (14.9 mL)
and the suspension was stirred for 45 min at room temperature. Comple-
tion of the reaction was confirmed by TLC (CHCl3/MeOH 20:1). The
suspension was then filtered through Celite and the filtrate was extracted
with CH2Cl2. The organic layer was washed with saturated aqueous
NaHCO3 solution and brine, dried (Na2SO4), and concentrated. The resi-
due was exposed to high vacuum for 30 min, and was then treated with a
solution of benzyloxyacetyl chloride (64 mL, 388 mmol) in THF (7.5 mL)
for 1.5 h. The progress of the reaction was monitored by TLC (CHCl3/
MeOH 20:1). Upon its completion, the mixture was diluted with EtOAc,
and the organic layer was washed with saturated aqueous NaHCO3 solu-
tion and brine, dried (Na2SO4), and concentrated. The residue was puri-
fied by column chromatography on silica gel (hexane/EtOAc 2:3) to give
31 (435 mg, 89%). [a]D =ꢀ10.38 (c=1.1, CHCl3); 1H NMR (500 MHz,
CDCl3): d=8.16–7.23 (m, 25H; 5 Ph), 6.57 (d, 1H, JNH,5 =9.7 Hz; NH-c),
6.03 (dd, 1H, J6,7 =4.3, J7,8 =8.9 Hz; H-7b), 5.67 (m, 1H; H-8c), 5.49 (dd,
1H, J6,7 =1.7, J7,8 =10.3 Hz; H-7c), 5.44 (m, 3H; H-8b, PhCH2), 5.38 (app
t, 1H, J1,2 =8.0, J2,3 =9.2 Hz; H-2a), 5.21 (m, 1H; H-4c), 5.11 (app t, 1H;
H-5b), 4.97–4.72 (m, 6H; PhCH2), 4.68 (d, 1H; H-1a), 4.50 (brt, 1H; H-
J
NH,5 =8.6 Hz; NH-c), 5.00 (s, 1H; H-5b), 4.96–4.48 (m, 9H; H-6c,
Cl3CCH2, PhCH2), 4.38 (d, 1H, J1,2 =8.0 Hz; H-1a), 4.35 (dd, 1H, Jgem
=
12.6, J8,9 =2.9 Hz; H-9c), 4.25 (m, 3H; H-4b, H-6b, H-9b), 4.12 (m, 2H;
H-6a, H-9’b), 4.02 (m, 2H; H-9’c, TMSCH2CH2), 3.80 (m, 7H; H-6’a,
COOMe, OMe), 3.57 (m, 5H; H-3a, H-4a, H-5a, H-5c, TMSCH2CH2),
3.39 (app t, 1H, J2,3 =9.2 Hz; H-2a), 2.59 (dd, 1H, Jgem =12.6, J3eq,4
4.9 Hz; H-3ceq), 2.25 (m, 2H; H-3bax, H-3beq), 2.11–1.91 (m, 21H; 7 Ac),
1.55 (app t, 1H, 3ax,4 =12.6 Hz; H-3cax), 1.06 ppm (app t, 2H;
=
J
TMSCH2CH2); 13C NMR (100 MHz, CDCl3): d=170.8, 170.7, 170.2,
169.9, 169.7, 169.5, 168.3, 164.2, 159.2, 153.6, 151.8, 138.7, 138.6, 135.1,
130.8, 129.8, 128.5, 128.3, 128.2, 128.2, 128.2, 127.8, 127.8, 127.6, 127.5,
127.4, 113.7, 103.0, 98.9, 95.9, 95.6, 84.6, 81.8, 78.1, 77.2, 75.6, 75.4, 74.5,
74.3, 74.2, 73.8, 71.7, 71.2, 69.5, 69.3, 69.2, 67.4, 67.0, 63.5, 62.1, 60.7, 55.2,
53.2, 53.1, 51.0, 37.5, 35.8, 29.7, 21.0, 20.8, 20.8, 20.7, 20.5, 20.3, 18.5,
ꢀ1.4 ppm; HRMS: m/z: calcd for C77H95Cl3N2O31Si+Na+: 1699.4651
[M+Na]+; found: 1699.4626.
4b), 4.40 (m, 4H; H-6b, H-9b, H-6c, H-9c), 4.29 (dd, 1H, Jgem =12.0, J5,6
5.2 Hz; H-6a), 4.17 (m, 3H; H-9’b, H-5c, H-9’c), 4.05 (m, 2H;
BnOCH2CO), 3.96 (m, 6H; H-3a, H-6’a, COOMe, TMSCH2CH2), 3.82
=
(m, 2H; H-4a, H-5a), 3.66 (m, 1H; TMSCH2CH2), 2.73 (dd, 1H, Jgem
=
12.6, J3eq,4 =4.6 Hz; H-3ceq), 2.39 (m, 2H; H-3bax, H-3beq), 2.26–2.07 (7s,
21H; 7 Ac), 1.94 (app t, 1H, Jgem =12.6 Hz; H-3cax), 1.00 ppm (app t,
2H; TMSCH2CH2); 13C NMR (125 MHz, CDCl3): d=170.7, 170.3, 170.1,
170.1, 169.6, 169.5, 168.2, 165.1, 164.3, 151.7, 138.2, 137.7, 136.7, 135.0,
132.8, 130.1, 129.7, 128.5, 128.4, 128.4, 128.2, 128.2, 128.1, 128.0, 127.9,
127.7, 127.6, 127.5, 127.4, 100.3, 98.8, 96.0, 82.7, 78.2, 77.2, 75.6, 74.9, 74.5,
74.2, 73.7, 73.5, 73.2, 72.0, 70.6, 69.6, 69.2, 69.2, 68.8, 68.1, 67.0, 67.0, 66.6,
63.4, 62.1, 61.0, 53.5, 53.0, 48.6, 37.3, 35.8, 29.6, 22.6, 21.0, 20.8, 20.7, 20.7,
20.6, 20.5, 20.4, 17.7, ꢀ1.6 ppm; HRMS: m/z: calcd for C82H98N2O31Si+
Na+: 1657.5821 [M+Na]+; found: 1657.5821.
2-(Trimethylsilyl)ethyl [methyl 4,7,8,9-tetra-O-acetyl-3,5-dideoxy-5-(2,2,2-
trichloroethoxycarbamoyl)-d-glycero-a-d-galacto-2-nonulopyranosylo-
nate]-(2!4)-(7,8,9-tri-O-acetyl-5-benzyloxycarbamoyl-3,5-dideoxy-d-
glycero-a-d-galacto-2-nonulopyranosylono-1,5-lactam)-(2!6)-2-O-ben-
zoyl-3,4-di-O-benzyl-b-d-glucopyranoside (30): 2,3-Dichloro-5,6-dicyano-
p-benzoquinone (4.4 mg, 19.4 mmol) was added to a solution of com-
pound 29 (25.6 mg, 15.2 mmol) in CH2Cl2 (400 mL)/H2O (20 mL). The sus-
pension was stirred for 2 h at room temperature, whereupon completion
of the reaction was confirmed by TLC (CHCl3/MeOH 15:1). The mixture
was diluted with CHCl3, and the organic layer was washed with saturated
aqueous NaHCO3 solution and brine, dried over Na2SO4, concentrated,
and exposed to high vacuum for 7 h. The crude material was redissolved
in pyridine (500 mL) and then benzoic anhydride (16.8 mg, 74.2 mmol)
and DMAP (3.0 mg, 24.6 mmol) were added to the solution. The resulting
mixture was stirred for 20 h at room temperature. After completion of
the reaction was indicated by TLC (PhMe/EtOAc 1:1), the reaction mix-
ture was concentrated and the residual volatiles were co-evaporated with
toluene. The residue was redissolved in EtOAc, and this solution was
washed with 2m aqueous HCl, water, saturated aqueous NaHCO3 solu-
tion, and brine, dried over Na2SO4, and concentrated. The residue was
2-(Trimethylsilyl)ethyl (methyl 4,7,8,9-tetra-O-acetyl-5-benzyloxyacetami-
do-3,5-dideoxy-d-glycero-a-d-galacto-2-nonulopyranosylonate)-(2!4)-
(methyl 7,8,9-tri-O-acetyl-5-benzyloxycarbamoyl-3,5-dideoxy-d-glycero-
a-d-galacto-2-nonulopyranosylonate)-(2!6)-2-O-benzoyl-3,4-di-O-
benzyl-b-d-glucopyranoside (32):
A 10% triethylamine solution in
MeCN (6.0 mL) and water (3.0 mL) were added to a flask containing
compound 31 (435 mg, 266 mmol). The mixture was stirred for 19 h at
408C, with monitoring of the reaction by TLC (CHCl3/MeOH 10:1).
Upon its completion, the mixture was concentrated and the residual vola-
tiles were co-evaporated with toluene. The residue was redissolved in
4644
www.chemeurj.org
ꢀ 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Chem. Eur. J. 2009, 15, 4637 – 4648

Synthesis of Ganglioside HLG-2
FULL PAPER
CHCl3, and this solution was washed with 2m aqueous HCl and brine,
dried (Na2SO4), and concentrated, and the residue was exposed to high
vacuum for 2 h. The crude material was redissolved in pyridine (2.0 mL),
and acetic anhydride (500 mL) and DMAP (5.0 mg) were added to the so-
lution. The resulting mixture was stirred for 1 h at room temperature, as
the progress of the reaction was monitored by TLC (CHCl3/MeOH 10:1).
After quenching with EtOH, the mixture was concentrated and the resid-
ual volatiles were co-evaporated with toluene. The residue was redis-
solved in CHCl3, and this solution was washed with 2m aqueous HCl,
water, and brine, dried (Na2SO4), and concentrated. The residue was ex-
posed to high vacuum for 2 h, redissolved in DMF (6.7 mL), and then io-
domethane (133 mL, 2.13 mmol) and K2CO3 (441 mg, 3.19 mmol) were
added at 08C. The resulting mixture was stirred for 1 h at room tempera-
ture. After completion of the reaction had been indicated by TLC
(CHCl3/MeOH 20:1), triethylamine was added to the reaction mixture.
The resulting mixture was extracted with EtOAc, and the combined ex-
tracts were washed with water and brine, dried (Na2SO4), and concentrat-
ed. The residue was purified by column chromatography on silica gel
(PhMe/EtOAc 1:1) to give 32 (326 mg, 73%). [a]D =+2.48 (c=2.7,
CHCl3); 1H NMR (600 MHz, CDCl3): d=8.00–7.09 (m, 25H; 5 Ph), 6.25
(d, 1H, JNH,5 =11.0 Hz; NH-c), 5.56 (d, 1H, JNH,5 =9.7 Hz; NH-b), 5.48
(m, 3H; H-7b, H-8b, H-8c), 5.27 (m, 2H; H-7c, PhCH2), 5.20 (app t, 1H,
4.5 Hz; H-3ceq), 2.22 (dd, 1H, Jgem =12.8, J3eq,4 =3.7 Hz; H-3beq), 2.18–1.88
(m, 34H; H-3cax, 11 Ac), 1.79 (app t, 1H; H-3bax), 0.81 ppm (m, 2H;
TMSCH2CH2); 13C NMR (100 MHz, CDCl3): d=171.9, 171.2, 170.6,
170.5, 170.4, 170.4, 170.1, 170.0, 169.6, 169.1, 167.7, 167.6, 167.1, 165.0,
133.2, 129.8, 129.5, 128.4, 100.5, 98.5, 98.0, 77.6, 77.2, 73.2, 72.5, 72.4, 72.2,
71.8, 71.3, 68.4, 68.0, 67.7, 67.6, 67.5, 67.2, 64.0, 62.7, 53.1, 52.3, 49.1, 48.8,
38.7, 38.2, 29.7, 23.3, 21.2, 21.2, 20.9, 20.9, 20.8, 20.7, 20.7, 20.7, 20.6, 20.6,
17.8, ꢀ1.5 ppm; HRMS: m/z: calcd for C62H86N2O34Si+Na+: 1453.4729
[M+Na]+; found: 1453.4728.
(Methyl 4,7,8,9-tetra-O-acetyl-5-acetoxyacetamido-3,5-dideoxy-d-glycero-
a-d-galacto-2-nonulopyranosylonate)-(2!4)-(methyl 5-acetamido-7,8,9-
tri-O-acetyl-3,5-dideoxy-d-glycero-a-d-galacto-2-nonulopyranosylonate)-
(2!6)-3,4-di-O-acetyl-2-O-benzoyl-a-d-glucopyranosyl trichloroacetimi-
date (34): CF3COOH (500 mL) was added to a solution of compound 33
(70.0 mg, 48.9 mmol) in CH2Cl2 (1.0 mL) at 08C. The mixture was stirred
for 4 h at room temperature with monitoring of the reaction by TLC
(CHCl3/MeOH 10:1), then concentrated, and the remaining volatiles
were co-evaporated with toluene. The residue was subjected to column
chromatography on silica gel (CHCl3/MeOH 35:1) to give the 1-OH de-
rivative (63.8 mg). This compound was exposed to high vacuum for 12 h
and then redissolved in CH2Cl2 (1.0 mL). Trichloroacetonitrile (49 mL,
489 mmol) and 1,8-diazabicycloACHTUNTRGNEU[GN 5.4.0]undec-7-ene (2.2 mL, 14.7 mmol)
J
1,2 =8.3, J2,3 =8.9 Hz; H-2a), 4.98 (d, 1H; PhCH2), 4.87–4.52 (m, 7H; H-
were added to the solution, and the resulting mixture was stirred for 1 h
at 08C. Completion of the reaction was confirmed by TLC (CHCl3/
MeOH 10:1). The mixture was concentrated, and the residue was puri-
fied by column chromatography (CHCl3/MeOH 40:1) to give 34
(62.5 mg, 87%). [a]D =+41.68 (c=0.7, CHCl3); 1H NMR (400 MHz,
CDCl3): d=8.52 (s, 1H; Cl3CCNH), 7.98–7.40 (m, 5H; Ph), 6.67 (d, 1H,
4c, PhCH2), 4.44 (d, 1H; H-1a), 4.24 (dd, 1H, Jgem =12.4, J8,9 =2.1 Hz; H-
9b), 4.20 (m, 2H; H-6a, H-9c), 4.11 (m, 1H; H-5c), 4.02 (m, 2H; H-6b,
H-9’b), 3.81 (m, 15H; H-3a, H-4a, H-4b, H-5b, H-6c, H-9’c, COOMe,
BnOCH2CO, TMSCH2CH2), 3.60 (d, 1H, Jgem =10.3 Hz; H-6’a), 3.47 (m,
2H; H-5a, TMSCH2CH2), 2.66 (dd, 1H, Jgem =12.7, J3eq,4 =4.5 Hz; H-
3ceq), 2.33 (m, 4H; H-3beq, Ac), 2.16–1.77 (m, 20H; H-3bax, H-3cax, 6 Ac),
0.82 ppm (m, 2H; TMSCH2CH2); 13C NMR (100 MHz, CDCl3): d=170.9,
170.7, 170.5, 170.3, 170.2, 170.1, 170.0, 169.9, 167.5, 167.3, 165.2, 156.5,
138.3, 137.9, 137.8, 137.0, 136.8, 132.9, 130.1, 129.7, 129.0, 128.6, 128.4,
182.2, 128.2, 128.2, 128.0, 128.0, 127.8, 127.7, 127.5, 127.0, 125.3, 100.5,
98.6, 98.3, 82.5, 77.7, 77.2, 75.0, 74.9, 74.0, 73.7, 73.5, 72.7, 72.3, 71.2, 69.2,
68.7, 68.1, 67.7, 67.4, 67.0, 66.8, 66.5, 62.9, 62.6, 62.4, 53.2, 52.1, 51.4, 48.3,
39.6, 38.2, 29.7, 21.4, 21.3, 21.2, 20.8, 20.8, 20.6, 20.4, 17.9, ꢀ1.5 ppm;
HRMS: m/z: calcd for C83H102N2O32Si+Na+: 1689.6083 [M+Na]+;
found: 1689.6083.
J
J
1,2 =3.7 Hz; H-1a), 6.03 (d, 1H, JNH,5 =10.5 Hz; NH-b), 5.76 (d, 1H,
NH,5 =10.1 Hz; NH-c), 5.75 (app t, 1H, J2,3 =10.1, J3,4 =9.6 Hz; H-3a),
5.61 (m, 1H; H-8b), 5.39 (m, 4H; H-2a, H-4a, H-7c, H-8c), 5.16 (dd, 1H,
6,7 =2.3, J7,8 =8.7 Hz; H-7b), 4.81 (m, 1H; H-4c), 4.58 (d, 1H, Jgem
J
=
15.1 Hz; AcOCH2CO), 4.40 (dd, 1H, Jgem =12.2, J8,9 =2.3 Hz; H-9b), 4.31
(dd, 1H, J5,6 =12.4, J6,7 =2.8 Hz; H-6c), 4.27 (d, 1H; AcOCH2CO), 4.20
(brd, 1H; H-5a), 3.96 (m, 13H; H-6a, H-5b, H-6b, H-9’b, H-5c, H-6c, H-
9’c, COOMe), 3.65 (m, 1H; H-4b), 3.42 (app d, 1H; H-6’a), 2.62 (dd, 1H,
J
gem =12.6, J3eq,4 =4.4 Hz; H-3ceq), 2.34–1.97 (m, 34H; H-3beq, 11 Ac), 1.90
(app t, 1H; H-3cax), 1.83 ppm (app t, 1H, gem =12.6 Hz; H-3bax);
J
13C NMR (100 MHz, CDCl3): d=171.9, 171.2, 170.6, 170.5, 170.4, 170.2,
170.0, 169.6, 168.8, 167.7, 167.6, 167.0, 165.3, 160.6, 133.6, 129.8, 128.6,
128.5, 98.3, 98.0, 93.2, 90.7, 77.2, 72.5, 72.2, 71.3, 70.8, 70.4, 70.2, 68.3,
67.9, 67.6, 67.5, 67.2, 67.1, 64.0, 62.7, 61.6, 53.0, 52.5, 49.1, 48.8, 38.7, 38.1,
31.9, 30.0, 29.7, 29.3, 23.3, 22.6, 21.2, 20.9, 20.8, 20.8, 20.7, 20.7, 20.6,
14.1 ppm; MALDI-TOF MS: m/z: calcd for C59H74Cl3N3O34 +Na+:
1496.3 [M+Na]+; found: 1496.3.
2-(Trimethylsilyl)ethyl (methyl 4,7,8,9-tetra-O-acetyl-5-acetoxyacetami-
do-3,5-dideoxy-d-glycero-a-d-galacto-2-nonulopyranosylonate)-(2!4)-
(methyl 5-acetamido-7,8,9-tri-O-acetyl-3,5-dideoxy-d-glycero-a-d-galac-
to-2-nonulopyranosylonate)-(2!6)-3,4-di-O-acetyl-2-O-benzoyl-b-d-glu-
copyranoside (33): 20% Pd(OH)2 on activated carbon (273 mg) was
added to
a solution of compound 32 (273 mg, 164 mmol) in EtOH
(6.2 mL)/THF (2.0 mL)/AcOH (0.8 mL) and the suspension was stirred
under a hydrogen stream for 1 h at room temperature. After completion
of the reaction had been indicated by TLC (CHCl3/MeOH 10:1), the re-
action mixture was filtered through Celite and the filtrate was concen-
trated. The residue was exposed to high vacuum for 12 h. The crude ma-
terial was redissolved in pyridine (2.0 mL), and acetic anhydride (1.0 mL)
and DMAP (5.0 mg) were added to the solution. The resulting mixture
was stirred for 6.5 h at room temperature with monitoring of the reaction
by TLC (CHCl3/MeOH 15:1). After quenching with EtOH, the mixture
was concentrated and the remaining volatiles were co-evaporated with
toluene. The residue was redissolved in EtOAc, and this solution was
washed with 2m aqueous HCl, water, saturated aqueous NaHCO3 solu-
tion, and brine, dried (Na2SO4), and concentrated. The residue was puri-
fied by column chromatography on silica gel (CHCl3/MeOH 50:1) to give
33 (209 mg, 89%). [a]D =+4.38 (c=2.0, CHCl3); 1H NMR (600 MHz,
CDCl3): d=8.00–7.42 (m, 5H; Ph), 6.05 (d, 1H, JNH,5 =10.3 Hz; NH-b),
5.78 (d, 1H, JNH,5 =9.6 Hz; NH-c), 5.60 (m, 1H; H-8c), 5.45 (dd, 1H,
AHCTUNGTERG(NNUN 2S,3R,4E)-2-N-tert-Butoxycarbonyl-1O,2N-isopropylidene-3-hydroxy-15-
methylhexadec-4-ene (37): [Cp2Zr(H)Cl] (2.20 g, 8.54 mmol) was added
to a solution of compound 12 (1.17 g, 6.17 mmol) in THF (12.0 mL) at
08C and the resulting mixture was stirred for 1 h at room temperature
and then cooled to 08C once more. The resulting yellow solution was
treated first with a solution of 11 (1.09 g, 4.75 mmol) in THF (12 mL)
and then with zinc bromide (270 mg, 1.19 mmol) and the mixture was
stirred for 18 h at room temperature. Completion of the reaction was
confirmed by TLC (CHCl3/MeOH 10:1). After the addition of Rochelle
salt, the suspension was filtered through Celite and the filtrate was ex-
tracted with EtOAc. The organic phase was washed with water and brine,
dried over Na2SO4, and concentrated. The residue was purified by
column chromatography on silica gel (hexane/EtOAc 10:1!8:1) to give
37 (1.06 g, 56%). [a]D =ꢀ39.18 (c=1.0, CHCl3); 1H NMR (400 MHz,
CDCl3): d=5.75 (m, 1H), 5.45 (dd, 1H, J=5.1, 15.7 Hz), 4.14 (m, 2H),
4.03 (brs, 1H), 3.84 (brs, 1H), 2.05 (m, 2H), 1.54 (m, 15H; 5 Me), 1.36
(m, 2H), 1.20 (m, 15H; -CH2-, H-15), 0.86 ppm (d, 6H, J=6.6 Hz; CH-
J
6,7 =2.1, J7,8 =8.3 Hz; H-7b), 5.41 (m, 1H; H-8b), 5.35 (t, 1H, J2,3 =J3,4
9.6 Hz; H-3a), 5.23 (m, 2H; H-2a, H-4a), 5.16 (dd, 1H, J6,7 =2.1, J7,8
8.9 Hz; H-7c), 4.81 (m, 1H; H-4c), 4.57 (d, 1H,
AcOCH2CO), 4.56 (d, 1H, J1,2 =8.2 Hz; H-1a), 4.40 (dd, 1H, Jgem =11.7,
8,9 =1.3 Hz; H-9c), 4.35 (dd, 1H, Jgem =12.0, J8,9 =2.4 Hz; H-9b), 4.27 (d,
=
=
AHCTUNGTRENNUNG
(CH3)2); 13C NMR (100 MHz, CDCl3): d=133.4, 128.1, 94.4, 74.0, 64.9,
62.3, 39.0, 32.4, 32.3, 31.9, 29.9, 29.6, 29.5, 29.3, 29.2, 29.1, 29.0, 28.4, 27.9,
27.4, 26.2, 24.6, 22.6, 14.1 ppm; HRMS: m/z: calcd for C25H47NO4 +Na+:
448.3403 [M+Na]+; found: 448.3405.
J
gem =15.8 Hz;
J
1H; AcOCH2CO), 4.05 (m, 3H; H-5b, H-9’b, H-5c), 3.89 (m, 11H; H-6a,
H-6b, H-6c, H-9’c, COOMe, TMSCH2CH2), 3.65 (m, 2H; H-5a, H-4b),
AHCTUNGTRENNUNG
3.52 (m, 2H; H-6’a, TMSCH2CH2), 2.62 (dd, 1H, Jgem =12.8, J3eq,4
=
Chem. Eur. J. 2009, 15, 4637 – 4648
ꢀ 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.chemeurj.org
4645

H. Ando, M. Kiso et al.
compound 37 (614 mg, 1.44 mmol). The mixture was stirred for 4 h at
458C, as the progress of the reaction was monitored by TLC (hexane/
EtOAc 1:1). The reaction mixture was then concentrated, the remaining
volatiles were co-evaporated with toluene, and the residue was extracted
with CHCl3. The organic phase was washed with water, saturated aque-
ous NaHCO3 solution, and brine, dried over Na2SO4, and concentrated.
The residue was purified by column chromatography on silica gel
(hexane/EtOAc 3:1) to give 38 (372 mg, 67%). [a]D =ꢀ3.68 (c=1.8,
ACHTUNGTRENNUNG
1
CHCl3); H NMR (400 MHz, CDCl3): d=5.77 (m, 1H), 5.52 (dd, 1H, J=
6.6, 15.4 Hz), 5.36 (d, 1H, J=8.1 Hz; NH), 4.29 (br, 1H), 3.81 (m, 2H),
3.60 (brs, 1H), 3.11 (brs, 1H), 2.05 (m, 2H), 1.50 (m, 9H; 3 Me), 1.37
(m, 2H), 1.19 (m, 15H; -CH2-, H-15), 0.86 ppm (d, 6H, J=6.6 Hz; CH-
ACHTUNGTRENNUNG
(CH3)2); 13C NMR (100 MHz, CDCl3): d=156.2, 134.0, 133.8, 128.9, 79.7,
74.6, 73.1, 64.1, 55.4, 39.0, 32.3, 29.9, 29.7, 29.6, 29.5, 29.2, 29.1, 28.5, 28.3,
28.1, 27.9, 27.7, 27.5, 27.4, 22.6 ppm; HRMS: m/z: calcd for C22H43NO4 +
Na+: 408.3090 [M+Na]+; found: 408.3097.
ACHTUNGTRENNUNG(2S,3R,4E)-2-Amino-15-methylhexadec-4-ene-1,3-diol (39): CF3COOH
(2.68 mL, 35.0 mmol) was added to a solution of compound 38 (90 mg,
233 mmol) in CH2Cl2 (4.66 mL). The mixture was stirred for 15 min at
room temperature, as the progress of the reaction was monitored by TLC
(CHCl3/MeOH 3:1). The reaction mixture was then concentrated, the re-
maining volatiles were co-evaporated with toluene, and the residue was
extracted with CHCl3. The organic phase was washed with saturated
aqueous NaHCO3 solution, dried over Na2SO4, and concentrated. The
residue was purified by column chromatography on silica gel (CHCl3/
MeOH 10:1!3:1) to give 39 (54 mg, 81%). [a]D =ꢀ14.78 (c=1.8,
AHCTUNGTRENNUNG
2.16 mmol) and TIPSCl (185 mL, 865 mmol) were added to a solution of
compound 47 (327 mg, 432 mmol) in DMF (2.2 mL). The mixture was
stirred for 2.5 h at room temperature with monitoring of the reaction by
TLC (hexane/EtOAc 3:1). After quenching with MeOH, the mixture was
extracted with EtOAc. The organic phase was washed with water and
brine, dried over Na2SO4, and concentrated. The residue was purified by
column chromatography on silica gel (hexane/EtOAc 20:1) to give 48
(328 mg, 83%). [a]D =+1.88 (c=0.9, CHCl3); 1H NMR (600 MHz,
CDCl3): d=8.09–7.45 (m, 5H; Ph), 7.05 (d, 1H, J=8.3 Hz; NH), 5.81 (m,
1H), 5.54 (m, 2H), 4.24 (brs, 1H), 4.09 (dd, 1H, J=2.7, 10.3 Hz), 3.99
(m, 1H), 3.78 (dd, 1H, J=2.7, 10.3 Hz), 3.41 (d, 1H), 2.00 (m, 4H), 1.52
(m, 1H), 1.31 (m, 56H; -CH2-), 0.91 ppm (m, 30H; CH3CH2, (CH3)2CH,
{(CH3)2CH}3Si); 13C NMR (150 MHz, CDCl3): d=169.8, 164.9, 133.4,
133.3, 129.7, 129.3, 129.2, 128.5, 74.3, 74.3, 63.6, 53.0, 39.0, 32.3, 32.2, 31.9,
29.9, 29.7, 29.6, 29.6, 29.5, 29.5, 29.4, 29.3, 29.3, 29.3, 29.1, 27.9, 27.4, 24.8,
22.7, 22.6, 17.9, 17.7, 17.3, 14.1, 11.7, 11.5, 11.3 ppm; HRMS: m/z: calcd
for C57H105NO5Si+Na+: 934.7660 [M+Na]+; found: 934.7660.
1
CHCl3); H NMR (400 MHz, CDCl3): d=5.76 (m, 1H), 5.47 (dd, 1H, J=
7.0, 15.4 Hz), 4.06 (m, 1H), 3.65 (m, 2H), 2.87 (brs, 1H), 2.54 (brs, 2H;
NH2), 2.06 (m, 2H), 1.51 (m, 1H), 1.37 (m, 2H), 1.19 (m, 14H; -CH2-),
0.86 ppm (d, 6H, J=6.6 Hz; CHACHTNUGRTNEUNG
(CH3)2); 13C NMR (100 MHz, CDCl3):
d=134.6, 134.1, 129.2, 75.1, 63.7, 56.1, 39.0, 32.3, 29.9, 29.7, 29.6, 29.5,
29.2, 27.9, 27.4, 22.6 ppm; HRMS: m/z: calcd for C17H35NO2 +Na+:
308.2565 [M+Na]+; found: 308.2520.
1-Icosanal (41): NaHCO3 (631 mg, 7.51 mmol) and Dess–Martin periodi-
nane (251 mg, 593 mmol) were added to a solution of compound 40
(118 mg, 395 mmol) in CH2Cl2 (7.90 mL). The mixture was stirred for 1 h
at room temperature with monitoring of the reaction by TLC (hexane/
EtOAc 8:1). After quenching with saturated aqueous NaHCO3 solution
and saturated aqueous Na2S2O3 solution, the mixture was extracted with
CHCl3. The organic phase was washed with water and brine, dried over
Na2SO4, and concentrated. The residue was purified by column chroma-
tography on silica gel (hexane/EtOAc 20:1) to give 41 (104 mg, 89%).
The spectral data were identical to those of the known compound.[34]
AHCTUNGTERG(NNUN 2S,3R,4E)-3-O-Benzoyl-2-[(R)-2-(benzoyloxy)tetracosanoylamino]-15-
methyl-1-O-triisopropylsilylhexadec-4-ene-1,3-diol (49): Benzoic anhy-
dride (244 mg, 1.08 mmol) and DMAP (4.0 mg, 32.7 mmol) were added to
a solution of compound 48 (328 mg, 359 mmol) in pyridine (3.0 mL). The
mixture was stirred for 17 h at room temperature with monitoring of the
reaction by TLC (hexane/EtOAc 10:1). After quenching with water, the
mixture was extracted with EtOAc. The organic phase was washed with
2m aqueous HCl, water, saturated aqueous NaHCO3 solution, and brine,
dried over Na2SO4, and concentrated. The residue was purified by
column chromatography on silica gel (hexane/EtOAc 25:1) to give 49
(361 mg, 99%). [a]D =+19.08 (c=1.0, CHCl3); 1H NMR (600 MHz,
CDCl3): d=8.04–7.40 (m, 10H; 2 Ph), 6.67 (d, 1H, J=9.6 Hz; NH), 5.92
(m, 1H), 5.61 (m, 2H), 5.52 (m, 1H), 4.44 (m, 1H), 3.95 (dd, 1H, J=2.8,
10.4 Hz), 3.70 (dd, 1H, J=4.1, 10.4 Hz), 1.98 (m, 4H), 1.51 (m, 1H), 1.20
(m, 56H; -CH2-), 0.88 ppm (m, 30H; CH3CH2, (CH3)2CH,
{(CH3)2CH}3Si); 13C NMR (125 MHz, CDCl3): d=169.4, 165.2, 164.9,
137.0, 133.4, 132.8, 130.3, 129.7, 129.6, 129.3, 128.5, 128.3, 124.9, 74.4,
73.9, 61.9, 52.0, 39.0, 32.3, 32.2, 31.9, 29.9, 29.7, 29.6, 29.5, 29.4, 29.4, 29.3,
29.3, 28.8, 27.9, 27.4, 24.9, 22.7, 22.6, 17.7, 17.7, 14.1, 11.7, 11.6 ppm;
HRMS: m/z: calcd for C64H109NO6Si+Na+: 1038.7922 [M+Na]+; found:
1038.7922.
1,1-Dibromohenicos-1-ene (42): PPh3 (6.08 g, 23.2 mmol) was added to a
solution of CBr4 (3.85 g, 11.6 mmol) in CH2Cl2 (48 mL). The mixture was
stirred for 5 min at 08C, and then 41 (1.72 g, 5.80 mmol) was added. The
reaction mixture was stirred for 30 min at 08C and was then allowed to
warm to room temperature. After stirring for 1.5 h at room temperature,
water was added and the resulting mixture was extracted with CHCl3.
The organic phase was washed with saturated aqueous NaHCO3 solution
and brine, dried over Na2SO4, and concentrated. The residue was purified
by column chromatography on silica gel (hexane) to give 42 (2.52 g,
96%). [a]D =ꢀ0.68 (c=0.8, CHCl3); 1H NMR (400 MHz, CDCl3): d=
6.38 (t, 1H, J=7.3 Hz), 2.09 (q, 2H, J=7.3 Hz), 1.26 (m, 34H; -CH2-),
0.88 ppm (t, 3H, J=6.8 Hz; CH3CH2); 13C NMR (100 MHz, CDCl3): d=
138.9, 88.4, 33.0, 31.9, 29.7, 29.7, 29.6, 29.5, 29.4, 29.3, 29.0, 27.8, 22.7,
14.1 ppm; FAB-MS: m/z: calcd for C21H40Br2ꢀ2H: 448 [Mꢀ2H]+;
found: 448.
1-Henicosyne (15): At ꢀ788C, a 1.6m solution of nBuLi in hexane
(5.98 mL, 9.57 mmol) was added to a solution of compound 42 (1.44 g,
3.19 mmol) in THF (10.6 mL). The reaction mixture was stirred for 1 h at
room temperature. Completion of the reaction was confirmed by TLC
(hexane). After the addition of water, the mixture was extracted with
Et2O. The organic phase was washed with water and brine, dried over
Na2SO4, and concentrated. The residue was purified by column chroma-
tography on silica gel (hexane) to give 15 (903 mg, 97%). The spectral
data were identical to those of the known compound.[30]
AHCTUNGTERG(NNUN 2S,3R,4E)-3-O-Benzoyl-2-[(R)-2-(benzoyloxy)tetracosanoylamino]-15-
methylhexadec-4-ene-1,3-diol (50): A 1m solution of TBAF in THF
(212 mL, 212 mmol) and AcOH (50 mL, 850 mmol) were added to a solu-
tion of compound 49 (108 mg, 106 mmol) in THF (520 mL). The mixture
was stirred for 24 h at room temperature with monitoring of the reaction
by TLC (hexane/EtOAc 4:1). The mixture was then diluted with EtOAc,
washed with water and brine, dried over Na2SO4, and concentrated. The
4646
www.chemeurj.org
ꢀ 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Chem. Eur. J. 2009, 15, 4637 – 4648

Synthesis of Ganglioside HLG-2
FULL PAPER
residue was purified by column chromatography on silica gel (hexane/
EtOAc 4:1) to give 50 (82 mg, 90%). [a]D =+15.78 (c=0.8, CHCl3);
1H NMR (600 MHz, CDCl3): d=8.05–7.40 (m, 10H; 2 Ph), 6.84 (d, 1H,
J=8.2 Hz; NH), 5.88 (m, 1H), 5.60 (m, 2H), 5.43 (m, 1H), 4.29 (m, 1H),
3.68 (m, 2H), 2.70 (brs, 1H), 1.97 (m, 4H), 1.50 (m, 1H), 1.42 (m, 2H),
1.23 (m, 54H; -CH2-), 0.87 ppm (m, 9H; CH3CH2, (CH3)2CH); 13C NMR
(100 MHz, CDCl3): d=170.2, 166.2, 165.3, 137.4, 133.5, 133.3, 129.7,
129.6, 129.2, 128.6, 128.4, 124.3, 74.6, 74.4, 61.4, 53.5, 39.0, 32.3, 31.9, 29.9,
29.7, 29.4, 29.4, 29.3, 29.3, 28.7, 27.9, 27.4, 24.8, 22.7, 22.6, 14.1 ppm;
HRMS: m/z: calcd for C55H89NO6 +Na+: 882.6588 [M+Na]+; found:
882.6568.
62.6, 54.6, 54.0, 53.3, 48.3, 43.1, 40.4, 40.3, 35.9, 33.5, 33.1, 31.1, 30.9, 30.8,
30.8, 30.6, 30.5, 30.3, 29.2, 28.6, 26.2, 23.7, 23.1, 22.8, 14.4 ppm; HRMS:
m/z: calcd for C112H161N3O39ꢀ2H+Na+: 1432.8298 [Mꢀ2H+Na]ꢀ;
found: 1432.8299.
Acknowledgements
This work was financially supported by MEXT of Japan (WPI program
and Grant-in-Aid for Scientific Research to M.K., No. 1701007). We
thank Ms. Kiyoko Ito for technical assistance.
(Methyl 5-acetoxyacetamido-4,7,8,9-tetra-O-acetyl-3,5-dideoxy-d-glycero-
a-d-galacto-2-nonulopyranosylonate)-(2!4)-(methyl 5-acetamido-7,8,9-
tri-O-acetyl-3,5-dideoxy-d-glycero-a-d-galacto-2-nonulopyranosylonate)-
(2!6)-3,4-di-O-acetyl-2-O-benzoyl-b-d-glucopyranosyl-(1!1)-
(2S,3R,4E)-3-O-benzoyl-2-[(R)-2-(benzoyloxy)tetracosanoylamino]-15-
methylhexadec-4-ene-1,3-diol (51): AW-300 4 ꢂ molecular sieves
(550 mg) were added to a solution of compounds 34 (62.5 mg, 42.4 mmol)
and 50 (47.4 mg, 55.1 mmol) in CH2Cl2 (500 mL). The suspension was
stirred for 1.5 h at room temperature, then cooled to 08C, whereupon
TMSOTf (3.1 mL, 17.0 mmol) was added. Stirring was continued for
30 min at 08C. The mixture was then warmed to 108C and stirred for
12 h as the progress of the reaction was monitored by TLC (CHCl3/
MeOH 20:1). A further portion of TMSOTf (3.1 mL, 17.0 mmol) was
added and stirring was continued for 5 h at 108C. The mixture was then
warmed to room temperature and stirred for 1.5 h. After quenching with
triethylamine, the mixture was filtered through Celite and concentrated.
The residue was purified by column chromatography on silica gel
(CHCl3/MeOH 70:1!60:1) to give 51 (44.9 mg, 49%). [a]D =+9.78 (c=
0.9, CHCl3); 1H NMR (600 MHz, CDCl3): d=8.02–7.36 (m, 15H; 3 Ph),
6.53 (d, 1H, JNH =8.9 Hz; NH of sphingosine), 6.05 (d, 1H, JNH,5 =9.6 Hz;
NH-b), 5.74 (d, 1H, JNH,5 =10.3 Hz; NH-c), 5.65 (m, 1H; H-5d), 5.60 (m,
1H; H-8b), 5.42 (m, 4H; H-7b, H-8c, H-3d, H-4d), 5.20 (m, 5H; H-2a,
H-3a, H-4a, H-7c, H-2e), 4.80 (m, 1H; H-4c), 4.58 (d, 1H, Jgem =15.2 Hz;
AcOCH2CO), 4.46 (m, 1H; H-2d), 4.42 (d, 1H, J1,2 =8.2 Hz; H-1a), 4.40
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(dd, 1H, Jgem =12.1, J8,9 =2.5 Hz; H-9c), 4.32 (dd, 1H, Jgem =12.4, J8,9
=
2.8 Hz; H-9b), 4.26 (d, 1H; AcOCH2CO), 4.06 (m, 4H; H-5b, H-9’b, H-
5c, H-1d), 3.90 (dd, 1H, J5,6 =10.7, J6,7 =2.5 Hz; H-6b), 3.83 (m, 9H; H-
6a, H-6c, H-9’c, COOMe), 3.63 (m, 1H; H-4b), 3.53 (dd, 1H, Jgem =9.6,
J
1,2 =6.2 Hz; H-1’d), 3.44 (m, 1H; H-5a), 3.35 (app d, 1H; H-6’a), 2.61
(dd, 1H, Jgem =12.8, J3eq,4 =4.5 Hz; H-3ceq), 2.20–1.82 (m, 39H; H-3beq, H-
3cax, H-6d, H-3e, 11 Ac), 1.77 (t, 1H, Jgem =J3ax,4 =12.7 Hz; H-3bax), 1.51
(m, 1H; H-15d), 1.34–1.13 (m, 56H; -CH2-), 0.88 ppm (m, 9H; CH3CH2,
(CH3)2CH); 13C NMR (150 MHz, CDCl3): d=172.0, 171.2, 170.6, 170.4,
170.4, 170.3, 170.0, 169.9, 169.5, 169.5, 168.9, 167.7, 167.6, 167.0, 165.2,
165.1, 164.8, 137.2, 133.6, 133.3, 132.9, 130.1, 129.8, 129.7, 129.6, 129.2,
129.2, 128.7, 127.4, 128.3, 123.9, 100.4, 98.4, 98.0, 74.5, 74.3, 72.8, 72.5,
72.4, 72.3, 71.3, 71.3, 68.1, 68.0, 67.9, 67.7, 67.6, 67.2, 66.2, 64.0, 62.7, 62.7,
62.3, 53.2, 52.6, 50.6, 49.1, 48.8, 39.1, 38.8, 38.2, 32.2, 31.9, 29.9, 29.7, 29.6,
29.5, 29.4, 29.4, 29.3, 29.3, 28.8, 28.0, 27.4, 24.8, 23.3, 22.7, 22.7, 21.2, 21.2,
20.9, 20.9, 20.8, 20.7, 20.7, 20.6, 14.1 ppm; HRMS: m/z: calcd for
C112H161N3O39 +Na+: 2195.0605 [M+Na]+; found: 2195.0606.
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Ganglioside HLG-2 (1): A 28% solution of sodium methoxide in MeOH
was added to a solution of compound 51 (9.9 mg, 4.55 mmol) in MeOH
(0.6 mL)/THF (0.3 mL). The mixture was stirred for 4 h at room temper-
ature, as the progress of the reaction was monitored by TLC (CHCl3/
MeOH/water 4:3:1). Water (0.1 mL) was then added and stirring was
continued for 116 h at room temperature. After neutralization with
Dowex-50 (H+), the mixture was concentrated. The residue was purified
by column chromatography on Sephadex LH-20 (CHCl3/MeOH/water
5:6:2) to give 1 (6.4 mg, quant.). [a]D =ꢀ44.18 (c=0.2, CHCl3/MeOH/
H2O 5:6:2); 1H NMR (600 MHz, CD3OD): d=5.72 (m, 1H; H-5d), 5.45
(dd, 1H, J3,4 =7.6, J4,5 =15.2 Hz; H-4d), 4.39 (m, 1H; H-4c), 4.23 (d, 1H,
J
1,2 =8.3 Hz; H-1a), 3.19 (app t, 1H, J2,3 =8.9 Hz; H-2a), 2.90 (m, 2H; H-
3beq, H-3ceq), 2.11 (s, 3H; Ac), 2.03 (q, 2H; H-6d), 1.70 (m, 1H; H-15d),
1.56 (m, 4H; H-3bax, H-3cax, H-3e), 1.39–1.16 (m, 56H; -CH2-), 0.89 ppm
(m, 9H; CH3CH2, (CH3)2CH); 13C NMR (150 MHz, CD3OD): d=177.4,
177.3, 176.5, 174.9, 173.8, 135.0, 131.0, 104.8, 101.8, 99.9, 77.5, 76.4, 75.0,
74.5, 73.3, 73.1, 72.8, 72.6, 71.2, 70.9, 70.6, 70.2, 70.0, 69.1, 64.8, 64.6, 64.0,
Chem. Eur. J. 2009, 15, 4637 – 4648
ꢀ 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.chemeurj.org
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Received: December 22, 2008
Published online: March 19, 2009
4648
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Chem. Eur. J. 2009, 15, 4637 – 4648