Multi-component one-pot synthesis of the tumor-associated carbohydrate antigen globo-H based on preactivation of thioglycosyl donors

Article abstract of DOI:10.1021/jo070585g

(Chemical Equation Presented) Two efficient routes for the rapid assembly of the tumor-associated carbohydrate antigen Globo-H hexasaccharide 2 by a preactivation based iterative one-pot strategy are reported. The first method involves the sequential coup

Full text of DOI:10.1021/jo070585g

Multi-Component One-Pot Synthesis of the Tumor-Associated
Carbohydrate Antigen Globo-H Based on Preactivation of
Thioglycosyl Donors
Zhen Wang,† Luyuan Zhou,† Kheireddine El-Boubbou,† Xin-shan Ye,‡ and Xuefei Huang*,†
Department of Chemistry, The UniVersity of Toledo, 2801 West Bancroft Street, MS 602, Toledo, Ohio
43606, and The State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical
Sciences, Peking UniVersity, Xue Yuan Road 38, Beijing 100083, China
Xuefei.huang@utoledo.edu
ReceiVed March 21, 2007
Two efficient routes for the rapid assembly of the tumor-associated carbohydrate antigen Globo-H
hexasaccharide 2 by a preactivation based iterative one-pot strategy are reported. The first method involves
the sequential coupling of four glycosyl building blocks, leading to the desired hexasaccharide in 47%
overall yield in one-pot synthesis. Although model studies on constructing the challenging Gal-R-(1-
4)-Gal linkage in Gb3 trisaccharide yielded the desired R linkage almost exclusively, a similar approach
to assemble the hexasaccharide led to the formation of a significant amount of â anomer. As an alternative,
the second synthesis utilized three components in one pot with the Gal-R-(1-4)-Gal linkage preformed,
producing the desired hexasaccharide in a similar overall yield as the four component approach. Both
methods demonstrate that oligosaccharides containing R and â linkages within the same molecule can be
constructed in one pot via a preactivation based approach with higher glyco-assembly efficiencies than
the automated solid-phase synthesis strategy. Furthermore, because glycosylations can be carried out
independent of anomeric reactivities of donors, it is not necessary to differentiate anomeric reactivities
of building blocks through extensive protective group adjustment for chemoselective glycosylation. This
confers great flexibilities in the building block design, allowing matching of the donor with the acceptor,
leading to improved overall yield.
Introduction
carcinomas.1-5 As a distinct tumor-associated antigenic marker,
Globo-H has been conjugated to an immunogenic protein carrier,
Globo-H 1, a member of the globo series of glycolipids, is
found overexpressed in many types of human cancer cells
including breast cancer, prostate cancer, ovarian cancer, and lung
(1) Zhang, S.; Zhang, H. S.; Reuter, V. E.; Slovin, S. F.; Scher, H. I.;
Livingston, P. O. Clin. Cancer Res. 1998, 4, 295.
(2) Hakomori, S.; Zhang, Y. Chem. Biol. 1997, 4, 97.
(3) Zhang, S.; Cordon-Cardo, C.; Zhang, H. S.; Reuter, V. E.; Adluri,
S.; Hamilton, W. B.; Lloyd, K. O.; Livingston, P. O. Int. J. Cancer 1997,
73, 42.
* Corresponding author. Tel.: (419) 530-1507; fax: (419) 530-4033.
† The University of Toledo.
‡ Peking University.
10.1021/jo070585g CCC: $37.00 © 2007 American Chemical Society
Published on Web 07/21/2007
J. Org. Chem. 2007, 72, 6409-6420
6409

Wang et al.
which is effective in generating protective antibodies against
cancer cells. Such a construct has shown promising results in
clinical trials as an anti-breast cancer vaccine.6-9
a major hurdle in the conventional stepwise chemical synthesis.25
For a high-yielding one-pot reaction, glycosyl donors and
acceptors must be well-differentiated, allowing selective donor
activation and subsequent glycosylation of the acceptor. This
is traditionally accomplished by using building blocks containing
different types of activatable aglycons (selective activation),26,27
or carrying out glycosylations in the order of decreasing
anomeric reactivities of glycosyl donors (reactivity based
armed-disarmed approach),28,29 or a combination of both
strategies.30,31 Besides the integration of several glycosylation
processes into a single synthetic operation to furnish the target
oligosaccharide in a few hours, the advantages of our preacti-
vation based one-pot approach are (1) only one type of glycosyl
donor (i.e., p-tolyl thioglycosides) is used, thus simplifying the
synthetic design and (2) the preactivation approach allows us
to perform glycosylations without the need to follow decreasing
anomeric reactivities of donors, thus granting us much freedom
in choosing protective groups to match donors and accep-
tors.23,32,33 As part of the program toward establishing the scope
of our method, we explored the synthesis of Globo-H 2
containing both R and â linkages by a preactivation based multi-
component one-pot strategy.
Because of its biological significance, Globo-H has attracted
considerable attention from the synthetic community. It was first
assembled by Danishefsky and co-workers using the glycal
strategy,10,11 which was subsequently refined.12 Other elegant
syntheses include Schmidt and Lassaletta’s trichloroacetimidate
method,13 Boon and Zhu’s two-directional glycosylation,14
a
reactivity based one-pot method by Wong and co-workers,15-17
linear synthesis18 and automated solid-phase synthesis19 by the
Seeberger group, as well as syntheses of the non-reducing end
fragments.20,21 However, many of the reported methods required
various synthetic transformations of the oligosaccharide inter-
mediates. Furthermore, with both R and â linkages in Globo-
H, stereochemical control often became a formidable chal-
lenge.10,14,18 Therefore, a highly efficient assembly of the
Globo-H hexasaccharide is still in great demand.
We have previously developed a preactivation based iterative
one-pot strategy22-24 for construction of complex oligosaccha-
rides. One-pot synthesis refers to the glycosylation processes
where multiple step glycosylation reactions can be performed
in a single reaction flask without synthetic manipulation and
purification of intermediate oligosaccharides, thus overcoming
(4) Kannagi, R.; Levery, S. B.; Ishijamik, F.; Hakomori, S.; Schevinsky,
L. H.; Knowles, B. B.; Solter, D. J. Biol. Chem. 1983, 258, 8934.
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S.; Kannagi, R.; Hakomori, S. J. Biol. Chem. 1984, 259, 14773.
(6) Gilewske, T.; Ragupathi, G.; Bhuta, S.; Williams, L. J.; Musselli,
C.; Zhang, X.-F.; Bencsath, K. P.; Panageas, K. S.; Chin, J.; Hudis, C. A.;
Norton, L.; Houghton, A. N.; Livingston, P. O.; Danishefsky, S. J. Proc.
Natl. Acad. Sci. U.S.A. 2001, 98, 3270.
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shov, V.; Ragupathi, G.; Spassova, M.; Bornmann, W.; Slovin, S. F.; Scher,
H. I.; Livingston, P. O.; Lloyd, K. O.; Danishefsky, S. J. Proc. Natl. Acad.
Sci. U.S.A. 2000, 97, 2719.
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836.
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S.; Spassova, M.; Bornmann, W. G.; Fazzari, M.; Dantis, L.; Olkiewicz,
K.; Lloyd, K. O.; Livingston, P. O.; Danishefsky, S. J.; Scher, H. I. Proc.
Natl. Acad. Sci. U.S.A. 1999, 96, 5710.
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Kwon, O.; Danishefsky, S. J. J. Am. Chem. Soc. 1996, 118, 11488.
(11) Bilodeau, M. T.; Park, T. K.; Hu, S.; Randolph, J. T.; Danishefsky,
S. J.; Livingston, P. O.; Zhang, S. J. Am. Chem. Soc. 1995, 117, 7840.
(12) Allen, J. R.; Allen, J. G.; Zhang, X.-F.; Williams, L. J.; Zatorski,
A.; Ragupathi, G.; Livingston, P. O.; Danishefsky, S. J. Chem.sEur. J.
2000, 6, 1366.
(13) Lassaletta, J. M.; Schmidt, R. R. Liebigs Ann.Chem. 1996, 1417.
(14) Zhu, T.; Boons, G. J. Angew. Chem., Int. Ed. 1999, 38, 3495.
(15) Huang, C.-Y.; Thayer, D. A.; Chang, A. Y.; Best, M.; Hoffmann,
L.; Head, S.; Wong, C.-H. Proc. Natl. Acad. Sci. U.S.A. 2006, 100, 15.
(16) Wacowich-Sgarbi, S.; Rabuka, D.; Sgarbi, P. W. M.; Ichikawa, Y.
In Synthesis of Carbohydrates through Biotechnology; Wang, P. G.,
Ichikawa, Y., Eds.; ACS Symposium Series 873; American Chemical
Society: Washington, DC, 2004; pp 23-38.
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Chem., Int. Ed. 2001, 40, 1274.
(18) Bosse, F.; Marcauelle, L. A.; Seeberger, P. H. J. Org. Chem. 2002,
67, 6659.
Results and Discussion
Retrosynthetically, we divided Globo-H into four fragments,
A, BC, D, and EF. Although the exclusive R linkage between
A and B units can be produced according to our previous
studies,24 an R/â mixture will be formed between the newly
formed AB disaccharide and C due to the lack of neighboring
group participation.14 To circumvent this difficulty, BC disac-
charide will be prepared in advance with the desired â linkage.
An aminopropyl spacer will be introduced to the reducing end
(25) Yu, B.; Yang, Z.; Cao, H. Curr. Org. Chem. 2005, 9, 179 and
references cited therein.
(26) Pornsuriyasak, P.; Demchenko, A. V. Tetrahedron: Asymmetry
2005, 6, 433 and references cited therein.
(27) Kanie, O. In Carbohydrates in Chemistry and Biology; Ernst, B.,
Hart, G. W., Sinay, P., Eds.; Wiley-VCH: Weinheim, Germany, 2000; Vol.
1, pp 407-426.
(28) Fraser-Reid, B.; Wu, Z.; Udodong, U. E.; Ottosson, H. J. Org. Chem.
1990, 55, 6068.
(19) Werz, D. D.; Castagner, B.; Seeberger, P. H. J. Am. Chem. Soc.
2007, 129, 2770.
(20) For an example, see: Adinolfi, M.; Iadonisi, A.; Ravida´, A.;
Schiattarella, M. J. Org. Chem. 2005, 70, 5316.
(29) Koeller, K. M.; Wong, C.-H. Chem. ReV. 2000, 100, 4465 and
references cited therein.
(30) Tanaka, H.; Adachi, M.; Takahashi, T. Chem.sEur. J. 2005, 11,
849 and references cited therein.
(21) Tanaka, H.; Matoba, N.; Takanishi, T. Chem. Lett. 2005, 34, 400.
(22) Huang, L.; Huang, X. Chem.sEur. J. 2007, 13, 529.
(23) Huang, L.; Wang, Z.; Li, X.; Ye, X.-S.; Huang, X. Carbohydr. Res.
2006, 341, 1669.
(24) Huang, X.; Huang, L.; Wang, H.; Ye, X.-S. Angew. Chem., Int.
Ed. 2004, 42, 5221.
(31) Tanaka, H.; Adachi, M.; Tsukamoto, H.; Ikeda, T.; Yamada, H.;
Takahashi, T. Org. Lett. 2002, 4, 4213.
(32) Fraser-Reid, B.; Lo´pez, J. C.; Go´mez, A. M.; Uriel, C. Eur. J. Org.
Chem. 2004, 2004, 1387.
(33) Fraser-Reid, B.; Lo´pez, J. C.; Radhakrishnan, K. V.; Mach, M.;
Schlueter, U.; Gomez, A. M.; Uriel, C. J. Am. Chem. Soc. 2002, 124, 3198.
6410 J. Org. Chem., Vol. 72, No. 17, 2007

Synthesis of Carbohydrate Antigen Globo-H
TABLE 1. Evaluation of Buiding Blocks for BC Disaccharide
Synthesis
and a HMBC correlation between C1′ and H3. The erosion of
stereochemical control despite the presence of a participating
benzoyl group on C2 of the donor is presumably due to the
competing R directing effect of ethereal solvents.22,39-44 We
found that by substituting diethyl ether with a small amount of
acetonitrile to dissolve AgOTf, the formation of disaccharide
12R can be suppressed to negligible amounts with 72% yield
of the desired â disaccharide 12â (entry 6). The enhancement
of stereoselectivity is most likely due to the exclusion of diethyl
ether from the reaction and/or the â directing effect of
acetonitrile.45 The disaccharide 12â was then converted to 13
through standard transformations with an 85% overall yield
(Scheme 1a). The Troc group was introduced to direct the 1,2-
trans linkage in future glycosylation.
entry
donor
acceptor
product (yield)
1
2
3
4
5
3
7
8
7
8
4
4
4
5
6
9 (10%)a
10 (30%)a
11 (30%)a
12â (50-70%)a
12r (10-20%)a
12â (72%)b
6
8
6
a AgOTf was added as a solution in diethyl ether to the donor dissolved
in dichloromethane. Ratio of diethyl ether to dichloromethane was 1:2.
b AgOTf was added as a solution in acetonitrile to the donor dissolved in
dichloromethane. Ratio of acetonitrile to dichloromethane was 1:20.
The introduction of the R-(1-4) linkage at the DE junction
of Globo-H is challenging due to the low reactivity of the axial
4-hydroxyl group of the E ring and the difficulty in stereo-
chemical control. As a model, we explored first the formation
of DEF trisaccharide, known as Gb3 or Pk trisaccharide, which
is also highly enriched on the surface of a variety of cancer
cells and involved in many carbohydrate-receptor recognition
events.46 Many types of glycosyl donors, including fluoride,11,12
chloride,46 trichloroacetimidate,18,19,47 phosphite,48 phosphate,18,19
thioglycoside,49-51 sulfoxide,52 and thioimidates53 have been
examined in this reaction. The yield for the formation of the
Gal-R-(1-4)-Gal linkage is often not high with an anomeric
mixture of products.11,18,19,48,50 To test whether our glycosylation
condition is suitable to construct this key linkage, we examined
the glycosylation of lactoside 15 by thiogalactosyl donor 14
(Scheme 1b). Without any optimization, the desired trisaccharide
16 was obtained in 82% yield with only trace amounts of the â
anomer isolated. The R stereochemistry of the newly formed
of Globo-H 2, which can be used for future conjugation to an
immunogenic carrier protein.8,34
glycosidic linkage in 16 was confirmed by NMR (1JC1′′-H1′′
)
174 Hz).38 Encouraged by this result, we decided to test the
possibility of assembling Globo-H using four component one-
pot reactions with building blocks 18, 13, 19, and 15.
The assembly of the BC disaccharide was examined first
using several easily prepared glycosyl donor-acceptor pairs,
and the results are summarized in Table 1. Each glycosylation
was carried out by preactivating the glycosyl donor35 in mixed
solvents of dichloromethane and diethyl ether using the promoter
p-TolSOTf, formed in situ by reaction of p-TolSCl with AgOTf
at -78 °C,36 followed by addition of the acceptor.24 Reaction
of 337 and 437 was attempted without success with the recovery
of acceptor 4 (Table 1, entry 1). Removal of benzylidene in
donor 3 and replacing the levulinoyl with the benzoyl group
led to small improvements with the recovery of most acceptors
(entries 2 and 3). We next investigated the effect of substituting
the bulky phthalimide (Phth) on the acceptor with more sterically
accessible trichloroethoxy carbonyl (Troc) and azido moieties.
While the Troc group did not have a significant effect (entry
4), glycosylation of the azido containing acceptor 6 by donor 8
produced disaccharide 12â (1H NMR: δH1′ ) 4.79 ppm, 3JH1′,H2′
) 7.8 Hz) in 50-70% yield along with 10-20% 12R (1H
Preactivation of the fucosyl donor 18 at -78 °C with
p-TolSCl/AgOTf was followed by the addition of the first
acceptor 13 (Scheme 2a). A sterically hindered base, 2,4,6-tri-
tert-butyl-pyrimidine (TTBP)54 was added with the acceptor to
(39) Demchenko, A. V. Synlett 2003, 1225 and references cited therein.
(40) Tokimoto, H.; Fujimoto, Y.; Fukase, K.; Kusumoto, S. Tetrahe-
dron: Asymmetry 2005, 16, 441.
(41) Chiba, H.; Funasaka, S.; Mukaiyama, T. Bull. Chem. Soc. Jpn. 2003,
76, 1629.
(42) Adinolfi, M.; Barone, G.; Iadonisi, A.; Schiattarella, M. Tetrahedron
Lett. 2002, 43, 5573.
(43) Jona, H.; Mandai, H.; Chavasiri, W.; Takeuchi, K.; Mukaiyama, T.
Bull. Chem. Soc. Jpn. 2002, 75, 291.
(44) Demchenko, A. V.; Stauch, T.; Boons, G.-J. Synlett 1997, 818.
(45) Schmidt, R. R.; Behrendt, M.; Toepfer, A. Synlett 1990, 694.
(46) Kamath, V. P.; Yeske, R. E.; Gregson, J. M.; Ratcliffe, R. M.; Fang,
Y. R.; Palcic, M. M. Carbohydr. Res. 2004, 339, 1141 and references cited
therein.
(47) Chen, L.; Zhao, X.-E.; Lai, D.; Song, Z.; Kong, F. Carbohydr. Res.
2006, 341, 1174 and references cited therein.
(48) Hsieh, S.-Y.; Jan, M.-D.; Patkar, L. N.; Chen, C.-T.; Lin, C.-C.
Carbohydr. Res. 2005, 340, 49.
(49) Wang, C.; Li, Q.; Wang, H.; Zhang, L.; Ye, X.-S. Tetrahedron 2006,
62, 11657.
3
NMR: δH1′ ) 5.57 ppm, JH1′,H2′ ) 4.2 Hz) (entry 5). The
structure of 12R was confirmed by the presence of the Bz
carbonyl in the 13C NMR spectrum with a chemical shift of
δBz ) 166.5 ppm, 1JC1′-H1′ ) 174 Hz, indicating an R linakge,38
(34) Jennings, H. J.; Snood, R. K. In Neoglycoconjugates: Preparation
and Application; Lee, Y. C., Lee, R. T., Eds.; Academic Press: San Diego,
1994; p 325.
(50) Dohi, H.; Nishida, Y.; Takeda, T.; Kobayashi, K. Carbohydr. Res.
2002, 337, 983.
(51) Bhattacharyya, S.; Magnusson, B. G.; Wellmar, U.; Nilsson, U. J.
J. Chem. Soc., Perkin Trans. 1 2001, 886.
(35) Crich, D.; Sun, S. Tetrahedron 1998, 54, 8321.
(36) Martichonok, V.; Whitesides, G. M. J. Org. Chem. 1996, 61, 1702.
(37) Zhang, Z.; Ollman, I. R.; Ye, X.-S.; Wischnat, R.; Baasov, T.; Wong,
C.-H. J. Am. Chem. Soc. 1999, 121, 734.
(52) Sarkar, A. K.; Matta, K. L. Carbohydr. Res. 1992, 233, 245.
(53) Pornsuriyasak, P.; Demchenko, A. V. Carbohydr. Res. 2006, 341,
1458.
(38) Bock, K.; Pedersen, C. J. Chem. Soc., Perkin Trans. 2 1974, 293.
(54) Crich, D.; Smith, M.; Yao, Q.; Picione, J. Synthesis 2001, 323.
J. Org. Chem, Vol. 72, No. 17, 2007 6411

Wang et al.
SCHEME 1
SCHEME 2
neutralize trifluomethane sulfonic acid generated from glyco-
sylation. The reaction temperature was raised to -20 °C, and
the acceptor 13 was completely consumed as judged by TLC
analysis. The reaction temperature was cooled back down to
-78 °C, followed by sequential addition of AgOTf, p-TolSCl,
the second acceptor galactoside 19, TTBP, and warming up to
-20 °C. After 19 completely disappeared, the reaction tem-
perature was lowered to -78 °C again, and the last acceptor
lactoside 15, TTBP, AgOTf, and p-TolSCl were added to the
reaction medium. The fully protected Globo-H hexasaccharide
20R was obtained in 47% yield from the four component one-
pot reactions within 7 h, which were fully characterized by 1H
NMR, 13C NMR, gCOSY, gHMQC, gHMBC, and HRMS. In
addition, the anomer 20â was also produced in 23% yield.55
Both Globo-H anomers will be useful for immunological studies
as demonstrated by Danishefsky and co-workers.10 It is note-
worthy that thiogalactoside 19 has a higher anomeric reactivity
than disaccharide 13. This reversal of anomeric reactivity (i.e.,
a more reactive thioglycosyl acceptor is glycosylated by a less
reactive thioglycosyl donor) is not possible with the reactivity
based chemoselective glycosylation method.28,29,37 The preac-
tivation method allowed us to use the readily available building
(55) To determine the configuration of newly formed glycosyl bonds,
we once isolated the intermediate oligosaccharides during one-pot synthesis
and confirmed the linkages via NMR analysis.
6412 J. Org. Chem., Vol. 72, No. 17, 2007

Synthesis of Carbohydrate Antigen Globo-H
SCHEME 3
charide and disaccharide building blocks, the overall yield for
20R through the three component approach is similar to that of
the four component route.
Conclusion
block 19 instead of going through elaborate protective group
manipulations to achieve the precise anomeric reactivity.15-17
Recently, Seeberger and co-workers have reported an elegant
synthesis of Globo-H hexasaccharide19 with an overall yield of
30% for glyco-assembly using the automated solid-phase
synthesis pioneered by their group.56 As compared to the
automated method, our synthesis of the desired Globo-H
hexasaccharide achieved a higher glyco-assembly yield in a
shorter amount of time without consuming a large excess of
precious glycosyl building blocks. This underscores the advan-
tage of the preactivation based iterative one-pot oligosaccharide
synthesis method.
We have developed two routes for rapid assembly of the
tumor-associated carbohydrate antigen Globo-H hexasaccharide
2 by a preactivation based one-pot strategy, demonstrating that
oligosaccharides containing R and â linkages within the same
molecule can be constructed in one pot. Higher glyco-assembly
efficiencies have been achieved with only a near stoichiometric
amount of building blocks via the preactivation based one-pot
method as compared to the automated solid-phase synthesis
method. However, reliable stereochemical control in glycosy-
lation still remains a challenge, which will require further
developments and studies.
Deprotection of the hexasaccharide 20R was performed by
first removing the Troc protecting group with 1 M NaOH in
THF followed by acetylation. Staudinger reduction of the azide
group and subsequent catalytic hydrogenation over Pearlman’s
catalyst57 gave the fully deprotected Globo-H 2 in 50% overall
yield for all deprotection steps (Scheme 2b). Attempts to reduce
the azide and remove benzyl groups simultaneously by hydro-
genation failed even in the presence of additives such as
di-tbutyl carbonate58 and hydrochloric acid.
The formation of 20â in the 4 + 2 glycosylation is surprising
in view of our model studies on Gb3. Moreover, previous
syntheses of Globo-H hexasaccharides through the 4 + 2
coupling of tetrasaccharide donors with lactoside acceptors by
the Wong group17 and Schmidt and Lassaletta13 did not form
any stereoisomers. This unpredicted discrepancy highlights the
challenge of complex oligosaccharide assembly. The generation
of 20â may be due to the increased size of the tetrasaccharide
donor in our 4 + 2 coupling as compared to donor 14. We tested
next the lactoside acceptor 21 containing multiple electron
withdrawing benzoyl groups in the 4 + 2 glycosylation reaction,
as the less reactive acceptor is expected to be more selective.
However, the glycosylation yield was low with a large amount
of acceptor recovered.
Experimental Section
Characterization of Anomeric Stereochemistry. The stere-
ochemistries of the newly formed glycosidic linkages in Globo-H
3
hexasaccharides and intermediates were determined by JH1,H2
through 1H NMR and/or JC1,H1 through gHMQC 2-D NMR
1
(without 1H decoupling). Smaller coupling constants of JH1,H2
3
(around 3 Hz) indicate R linkages, and larger coupling constants
3JH1,H2 (7.2 Hz or larger) indicate â linkages. This can be further
1
1
confirmed by JC1,H1 (∼170 Hz) for R linkages and JC1,H1 (∼160
Hz) for â linkages.38
p-Tolyl 2-Azido-4,6-O-benzylidene-2-deoxy-1-thio-â-D-galac-
topyranoside (6). Trichloroethoxycarbonyl chloride (7.7 mL, 57.2
mmol) was added dropwise over a period of 30 min at room
temperature to a vigorously stirred solution of D-galactosamine
hydrochloride (10 g, 46.3 mmol) and NaHCO3 (11.8 g, 139.9
mmol) in water (90 mL). The mixture was stirred for another 2 h
and then filtered to give a yellowish solid, which was dried under
vacuum. The obtained crude solid (15 g) was dissolved in pyridine
(50 mL), and then acetic anhydride (30 mL) was added at 0 °C
over a period of 30 min. The mixture was stirred at room
temperature under N2 overnight and then quenched with ethanol
(20 mL) at 0 °C. The mixture was concentrated, and the resulting
residue was diluted with ethyl acetate and washed with a saturated
aqueous solution of NaHCO3, 10% HCl, water, and brine. The
organic phase was dried over Na2SO4, filtered, and concentrated.
Without separation, the obtained crude solid (21 g) and p-
toluenethiol (5.76 g, 46.3 mmol) were dissolved in CH2Cl2 (60 mL),
and the solution was cooled to 0 °C. Boron trifluoride etherate (17.8
mL, 160 mmol) was added dropwise at 0 °C, and the mixture was
stirred under N2 at room temperature for 6 h. The mixture was
diluted with CH2Cl2 (400 mL) and washed with a saturated aqueous
solution of NaHCO3 until the pH was 7 and then dried over Na2-
SO4, filtered, and concentrated. The obtained crude product was
recrystallized from EtOAc/hexanes to afford p-tolyl 3,4,6-tri-O-
acetyl-2-deoxy-2-N-trichloroethoxycarbonylamino-1-thio- â-D-ga-
lactopyranoside59 (S1) as a white solid (20.67 g, 76% for three
steps). 1H NMR (600 MHz, CDCl3): δ 1.98, 2.04, 2.13 (3s, 9H, 3
× COCH3), 2.34 (s, 3H, SPhCH3), 3.91-3.95 (m, 2H, H-2, H-5),
4.10-4.20 (m, 2H, H-6a, H-6b), 4.73-4.80 (m, 2H, CH2CCl3),
4.84 (d, 1H, J1,2 ) 10.2 Hz, H-1), 5.19 (dd, 1H, J2,3 ) 10.8 Hz,
J3,4 ) 2.4 Hz, H-3), 5.30 (d, 1H, JNH,2 ) 9.6 Hz, NH), 5.39 (d, 1H,
J3,4 ) 2.4 Hz, H-4), 7.10-7.16 (m, 2H), 7.40-7.46 (m, 2H); 13C
NMR (100 MHz, CDCl3): δ 20.9, 20.9, 21.4, 51.4, 62.0, 67.1, 71.2,
74.6, 74.7, 87.8, 95.7, 128.9, 129.9, 133.3, 138.7, 154.3, 170.5,
170.7, 170.8. ESI-MS [M + Na]+ C22H26NaCl3NO9S calcd 608.0,
obsd 608.3. p-Tolyl 3,4,6-tri-O-acetyl-2-deoxy-2-N-trichloroethoxy-
Since trisaccharide 16 was synthesized highly stereoselec-
tively, as an alternative to the four component one-pot strategy,
we examined a three component approach with the challenging
Gal-R-(1-4)-Gal linkage preformed. The p-methoxybenzyl
moiety in trisaccharide 16 was selectively removed to generate
acceptor 17 in 80% yield (Scheme 1b). One-pot sequential
glycosylation of fucoside 18 with disaccharide 13 and trisac-
charide 17 produced hexasaccharide 20R with a 74% overall
yield (Scheme 3), which was identical in all aspects to 20R
prepared via the four component approach, thus further confirm-
ing our stereochemical assignments. Starting from monosac-
(56) Plante, O. J.; Palmacci, E. R.; Seeberger, P. H. Science 2001, 291,
1523.
(57) Li, J.; Wang, J.; Czyryca, P. G.; Chang, H.; Orsak, T. W.; Evanson,
R.; Chang, C.-W. T. Org. Lett. 2004, 6, 1381.
(58) Cheshev, P. E.; Khatuntseva, E. A.; Gerbst, A. G.; Tsvetkov, Y.
E.; Shashkov, A. S.; Nifantiev, N. E. Russ. J. Bioorg. Chem. 2003, 29,
372.
(59) Mong, T. K.-K.; Lee, H.-K.; Duron, S. G.; Wong, C.-H. Proc. Natl.
Acad. Sci. U.S.A. 2003, 100, 797.
J. Org. Chem, Vol. 72, No. 17, 2007 6413

Wang et al.
carbonylamino-1-thio-â-D-galactopyranoside S1 (3 g, 5.1 mmol)
was dissolved in MeOH (12 mL), AcOH (6 mL), and CH2Cl2 (6
mL). Zn powder (6 g, 92 mmol) was added slowly at 0 °C, and the
mixture was stirred under N2 at room temperature for 1 h. The
mixture was filtered and concentrated to dryness. The resulting
residue was diluted with CH2Cl2 (200 mL) and washed with a
saturated aqueous solution of NaHCO3 until the pH was 7 and then
was dried over Na2SO4, filtered, and concentrated. Silica gel column
chromatography (EtOAc) afforded p-tolyl 3,4,6-tri-O-acetyl-2-
amino-2-deoxy-1-thio-â-D-galactopyranoside as a white solid (S2)
was dissolved in HBr in acetic acid (30 mL, 33% w/w, 173.6
mmol). After 6 h, the mixture was diluted with CH2Cl2 (240 mL)
and poured onto crushed ice in saturated NaHCO3 (600 mL). The
organic phase was separated and washed again with saturated
NaHCO3 until the pH was about 7 and then dried over Na2SO4,
filtered, and concentrated. The resulting residue, 2,6-lutidine (11.93
mL, 102.4 mmol), and Bu4NBr (3.3 g, 10.24 mmol) were dissolved
in CH2Cl2 (45 mL) and dry EtOH (8.5 mL, 6 equiv). The mixture
was stirred at room temperature under N2 overnight and then
concentrated and vacuum-dried to afford a colorless oil (10 g). The
obtained oil was dissolved in a mixture of CH2Cl2/MeOH (50 mL
each), and a 1 M solution of NaOMe (25.6 mL, 25.6 mmol) was
added at room temperature. The mixture was stirred for 2 h at room
temperature under N2 and then concentrated and vacuum-dried. The
obtained residue was dissolved in DMF (100 mL), and the solution
was cooled to 0 °C. NaH (4 g, 60% NaH in mineral oil, 100 mmol)
was added in portions, followed by the addition of BnBr (15 mL,
125 mmol). The mixture was stirred at room temperature under N2
for 4 h and then diluted with EtOAc (300 mL). The mixture was
washed with saturated NaHCO3 and water and then dried over Na2-
SO4, filtered, and concentrated. The resulting residue (8.5 g),
p-toluenethiol (6.7 g, 53.9 mmol), and HgBr2 (0.46 g, 1.28 mmol)
were put into CH3CN (20 mL), and the mixture was heated at 60
°C under N2 overnight. The solvent was evaporated, and then the
residue was diluted with CH2Cl2 (300 mL). The mixture was washed
with saturated NaHCO3, water, and 10% HCl and then dried over
Na2SO4, filtered, and concentrated. Silica gel column chromatog-
raphy (2:1 hexanes-/EtOAc) afforded p-tolyl 2-O-acetyl-3,4,6-tri-
O-benzyl-1-thio-â-D-galactopyranoside62 (S4) as a white solid (6.4
1
(1.8 g, 85.7%). H NMR (400 MHz, CDCl3): d 2.02, 2.05, 2.09
(3s, 9H, 3 × COCH3), 2.35 (s, 3H, SPhCH3), 3.18 (t, 1H, J ) 10.0
Hz, H-2), 3.91 (t, 1H, J ) 6.2 Hz, H-5), 4.11 (dd, 1H, J ) 6.2,
10.8 Hz, H-6a), 4.18 (dd, 1H, J ) 6.2, 10.8 Hz, H-6b), 4.49 (d,
1H, J1,2 ) 10.0 Hz, H-1), 4.78 (dd, 1H, J2,3 ) 10.0 Hz, J3,4 ) 3.2
Hz, H-3), 5.36 (d, 1H, J3,4 ) 3.2 Hz, H-4), 7.10-7.18 (m, 2H),
7.44-7.50 (m, 2H); 13C NMR (100 MHz, CDCl3): δ 20.8, 20.9,
20.9, 21.4, 49.9, 62.0, 66.8, 74.4, 75.2, 90.4, 128.4, 129.9, 133.3,
138.6, 170.4, 170.5, 170.7. ESI-MS [M + H]+ C19H26NO7S calcd
412.1, obsd 412.1. p-Tolyl 3,4,6-tri-O-acetyl-2-amino-2-deoxy-1-
thio-â-D-galactopyranoside (S2) (1.8 g, 4.37 mmol, 1 equiv) was
dissolved in MeOH (7.5 mL) and CH2Cl2 (7.5 mL). 1 M NaOMe
(2.2 mL, 2.2 mmol) was added, and the mixture was stirred at room
temperature for 2 h. The mixture was neutralized by concd HCl
until the pH was around 7 and then was concentrated and dried
under vacuum. The resulting residue, K2CO3 (1.5 g, 10.87 mmol),
and a catalytic amount of ZnCl2 (40 mg, 0.3 mmol) were dissolved
in MeOH (12 mL) and H2O (3 mL). Freshly prepared TfN360 (13
mL in CH2Cl2, 13.1 mmol) was added, and the mixture was stirred
at room temperature overnight. The solvent was evaporated, and
the resulting residue was diluted with EtOAc (100 mL). The mixture
was neutralized by concd HCl until the pH value was 6-7 and
then was concentrated to dryness. Silica gel column chromatography
(9:1 CH2Cl2-/MeOH) afforded p-tolyl 2-azido-2-deoxy-1-thio-â-
D-galactopyranoside61 (S3) as a white solid (1.2 g, 88%). 1H NMR
(600 MHz, CD3OD): δ 2.22 (s, 3H, SPhCH3), 3.37 (t, 1H, J ) 9.6
Hz, H-2), 3.39-3.40 (m, 2H, H-3, H-5), 3.58-3.68 (m, 2H, H-6a,
H-6b), 3.74 (d, 1H, J3,4 ) 2.4 Hz, H-4), 4.34 (d, 1H, J1,2 ) 9.6 Hz,
H-1), 7.01-7.06 (m, 2H), 7.33-7.40 (m, 2H); 13C NMR (100 MHz,
CD3OD): δ 21.3, 62.7, 64.6, 69.8, 75.4, 80.8, 88.5, 130.7, 130.8,
130.9, 133.9, 134.0, 139.3. ESI-MS [M + Na]+ C13H17NaN3O4S
calcd 334.1, obsd 334.3. The mixture of compound p-tolyl 2-azido-
2-deoxy-1-thio-â-D-galactopyranoside (S3) (1.2 g, 3.85 mmol),
camphorsulfonic acid (0.27 g, 1.16 mmol), and benzaldehyde
dimethylacetal (0.7 mL, 4.62 mmol) in toluene (20 mL) was stirred
at room temperature for 1 h and then diluted with EtOAc (200
mL). The mixture was washed with a saturated aqueous solution
of NaHCO3 and water and then dried over Na2SO4, filtered, and
concentrated. Silica gel column chromatography (2:1 hexanes-/
EtOAc) afforded 6 as a white solid (1.15 g, 75%). [R]D -31.9 (c
) 1, CH2Cl2); 1H NMR (600 MHz, CDCl3): δ 2.36 (s, 3H,
SPhCH3), 2.62 (d, 1H, J3,3-OH ) 10.2 Hz, OH), 3.45 (s, 1H, H-5),
1
g, 42% for five steps). H NMR (600 MHz, CDCl3): δ 2.04 (s,
3H, COCH3), 2.29 (s, 3H, SPhCH3), 3.54 (dd, 1H, J2,3 ) 9.6 Hz,
J3,4 ) 3.0 Hz, H-3), 3.59-3.67 (m, 3H, H-5, H-6a, H-6b), 3.97 (d,
1H, J3,4 ) 3.0 Hz, H-4), 4.41, 4.45, 4.52, 4.56 (4d, 4H, J ) 12.0
Hz, CH2Ph), 4.55 (d, 1H, J1,2 ) 9.6 Hz, H-1), 4.66 (d, 1H, J )
12.0 Hz, CH2Ph), 4.93 (d, 1H, J ) 12.0 Hz, CH2Ph), 5.39 (t, 1H,
J ) 9.6 Hz, H-2), 6.98-7.06 (m, 2H), 7.25-7.34 (m, 15H,
aromatic), 7.37-7.38 (m, 2H); 13C NMR (150 MHz, CDCl3): δ
21.3, 21.4, 69.0, 70.0, 72.2, 73.0, 73.8, 74.6, 77.8, 81.7, 87.3,
127.67, 127.70, 127.99, 128.03, 128.1, 128.2, 128.4, 128.6, 129.7,
130.0, 132.7, 137.8, 138.09, 138.12, 138.7, 169.7. ESI-MS [M +
Na]+ C36H38NaO6S calcd 621.2, obsd 621.5. p-Tolyl 2-O-acetyl-
3,4,6-tri-O-benzyl-1-thio-â-D-galactopyranoside (S4) (3 g, 5 mmol)
was dissolved in a mixture of CH2Cl2/MeOH (50 mL each), and 1
M NaOMe (10 mL, 10 mmol) was added at room temperature.
The mixture was stirred for 2 h at room temperature under N2 and
then was neutralized with Amberlite IR-120 until the pH was around
6-7. The mixture was concentrated and diluted with CH2Cl2 (300
mL) and washed with saturated NaHCO3, 10% HCl, and water and
then dried over Na2SO4, filtered, and concentrated. Silica gel column
chromatography (2:1 hexanes-/EtOAc) afforded p-tolyl 3,4,6-tri-
O-benzyl-1-thio-â-D-galactopyranoside (S5) as a white solid (2.56
g, 92%). 1H NMR (600 MHz, CDCl3): δ 2.29 (s, 3H, SPhCH3),
2.42 (d, 1H, J2,2-OH ) 2.4 Hz, OH), 3.46 (dd, 1H, J2,3 ) 9.6 Hz,
J3,4 ) 2.4 Hz, H-3), 3.63-3.66 (m, 3H, H-5, H-6a, H-6b), 3.95-
3.98 (m, 2H, H-2, H-4), 4.44 (d, 1H, J ) 12.0 Hz, CH2Ph), 4.47
(d, 1H, J1,2 ) 9.6 Hz, H-1), 4.49, 4.56, 4.67, 4.73, 4.89 (5d, 5H, J
) 12.0 Hz, CH2Ph), 6.98-7.05 (m, 2H), 7.25-7.35 (m, 15H,
aromatic), 7.44-7.45 (m, 2H); 13C NMR (150 MHz, CDCl3): δ
21.4, 68.9, 69.3, 72.6, 73.5, 73.8, 74.6, 77.8, 83.4, 89.0, 127.6,
127.9, 127.95, 128.04, 128.05, 128.2, 128.4, 128.7, 128.8, 128.9,
129.8, 133.1, 138.0, 138.1, 138.3, 138.9. ESI-MS [M + Na]+
C34H36NaO5S calcd 579.2, obsd 579.6. p-Tolyl 3,4,6-tri-O-benzyl-
1-thio-â-D-galactopyranoside (S5) (3.8 g, 6.8 mmol) and N,N-
dimethylamino pyridine (DMAP) (0.08 g, 0.68 mmol) were
dissolved in pyridine (20 mL), and then benzoyl chloride (2.38 mL,
20.5 mmol) was added. The mixture was stirred at room temperature
3.47 (t, 1H, J ) 10.2 Hz, H-2), 3.59 (dt, 1H, J3,4 ) 3.0 Hz. J2,3
)
10.2, J3,3-OH ) 10.2 Hz, H-3), 3.99 (dd, 1H, J ) 1.8, 12.6 Hz,
H-6a), 4.12 (d, 1H, J3,4 ) 3.0 Hz, H-4), 4.35 (d, 1H, J1,2 ) 9.6 Hz,
H-1), 4.37 (dd, 1H, J ) 1.8, 12.6 Hz, H-6b), 5.49 (s, 1H, CHPh),
7.11-7.12 (d, 2H, J ) 7.8 Hz, aromatic), 7.35-7.41 (m, 5H,
aromatic), 7.59-7.66 (m, 2H), 13C NMR (150 MHz, CDCl3): δ
21.6, 62.2, 69.5, 69.96, 70.00, 73.4, 74.6, 74.7, 85.2, 101.6, 101.7,
126.5, 126.8, 128.5, 129.7, 130.1, 135.0, 137.6, 139.0. ESI-MS [M
+ Na]+ C20H21NaO4S calcd 422.1, obsd 422.2; Comparison of the
NMR data with those reported in the literature37 confirmed the
identity of 6.
p-Tolyl 2-O-Benzoyl-3,4,6-tri-O-benzyl-1-thio-â-D-galactopy-
ranoside (8). â-D-Galactopyranosyl pentaacetate (10 g, 25.6 mmol)
(60) Nyffeler, P. T.; Liang, C.-H.; Koeller, K. M.; Wong, C.-H. J. Am.
Chem. Soc. 2002, 124, 10773.
(61) Luening, B.; Norberg, T.; Tejbrant, J. Glycoconjugate J. 1989, 6,
(62) Lee, J.-C.; Wu, C.-Y.; Apon, J. V.; Siuzdak, G.; Wong, C. H. Angew.
Chem., Int. Ed. 2006, 45, 2753.
5.
6414 J. Org. Chem., Vol. 72, No. 17, 2007

Synthesis of Carbohydrate Antigen Globo-H
under N2 for 4 h and then diluted with of CH2Cl2 (200 mL). The
mixture was washed with saturated NaHCO3, water, and 10% HCl
and then dried over Na2SO4, filtered, and concentrated. Silica gel
column chromatography (2:1 hexanes-/EtOAc) afforded 8 as a
white solid (4.2 g, 93%). [R]D +38.2 (c ) 1, CH2Cl2); 1H NMR
(600 MHz, CDCl3): δ 2.25 (s, 3H, SPhCH3), 3.65-3.69 (m, 4H,
H-3, H-5, H-6a, H-6b), 4.03 (d, 1H, J3,4 ) 2.4 Hz, H-4), 4.41, 4.45,
12R: [R]D +70.8 (c ) 4.5, CH2Cl2); 1H NMR (600 MHz, CDCl3):
δ 2.27 (s, 3H, SPhCH3), 3.26 (s, 1H, H-5), 3.57-3.65 (m, 3H,
H-3, H-6a′, H-6b′), 3.79 (t, 1H, J ) 9.6 Hz, H-2), 3.86 (d, 1H, J
) 12.0 Hz, H-6a), 4.06 (s, 1H, H-4), 4.09 (d, 1H, J3′,4′ ) 2.4 Hz,
H-4′), 4.17 (dd, 1H, J2′,3′ ) 10.8 Hz, J3′,4′ ) 2.4 Hz, H-3′), 4.22-
4.24 (m, 2H, H-5′, H-6b), 4.32 (d, 1H, J1,2 ) 9.6 Hz, H-1), 4.47,
4.51, 4.59, 4.66, 4.68, 4.93 (6d, 6H, J ) 12.0 Hz, CH2Ph), 5.16 (s,
1H, CHPh), 5.42 (dd, 1H, J1′,2′ ) 3.6 Hz, J2′,3′ ) 10.8 Hz, H-2′),
5.57 (d, 1H, J1′,2′ ) 3.6 Hz, H-1′), 6.90-6.99 (m, 2H), 6.98-7.02
(m, 4H, aromatic), 7.12-7.44 (m, 19H, aromatic), 7.50-7.59 (m,
2H), 7.72-7.82 (m, 2H); 13C NMR (150 MHz, CDCl3): δ 21.4,
59.6, 68.9, 69.2, 69.7, 70.0, 70.7, 71.9, 73.2, 73.4, 74.7, 75.0, 76.0,
76.9, 85.7, 93.1, 100.2, 126.1, 126.9, 127.78, 127.80, 127.82,
127.86, 127.87, 128.3, 128.45, 128.49, 128.51, 128.55, 129.68,
129.70, 129.9, 133.0, 134.3, 137.5, 138.2, 138.3, 138.4, 138.5,
166.5. ESI-MS [M + Na]+ C54H53N3NaO10S calcd 958.3, obsd
4.47, 4.59, 4.61 (5d, 5H, J ) 12.0 Hz, CH2Ph), 4.71 (d, 1H, J1,2
)
10.2 Hz, H-1), 4.97 (d, 1H, J ) 12.0 Hz, CH2Ph), 5.68 (t, 1H, J )
10.2 Hz, H-2), 6.96-6.97 (d, 2H, J ) 7.8 Hz, aromatic), 7.10-
7.15 (m, 5H, aromatic), 7.25-7.36 (m, 12H, aromatic), 7.41-7.42
(m, 2H, aromatic), 7.53-7.55 (m, 1H, aromatic), 8.00-8.07 (m,
2H); 13C NMR (150 MHz, CDCl3): δ 21.5, 69.2, 70.8, 72.1, 73.1,
73.9, 74.7, 78.0, 81.5, 87.5, 127.8, 127.99, 128.00, 128.1, 128.2,
128.4, 128.5, 128.6, 128.7, 128.8, 129.8, 130.0, 130.2, 130.5, 133.0,
133.4, 137.9, 138.0, 138.2, 138.8, 165.6. HRMS: [M + Na]+
C41H40NaO6S calcd 683.2443, obsd 683.2421.
1
1
958.4. gHMQC (without H decoupling): JC1′,H1′ ) 172.4 Hz,
1JC1,H1 ) 160.1 Hz.
General Procedure for Single Step Preactivation Based
Glycosylation. A solution of donor (0.060 mmol) and freshly
activated molecular sieve MS 4 Å (200 mg) in CH2Cl2 (2 mL) was
stirred at room temperature for 30 min, and cooled to -78 °C,
which was followed by the addition of AgOTf (47 mg, 0.18 mmol)
dissolved in Et2O (1 mL) without touching the wall of the flask.
After 5 min, orange p-TolSCl (9.5 µL, 0.060 mmol) was added
through a microsyringe. Since the reaction temperature was lower
than the freezing point of p-TolSCl, p-TolSCl was added directly
into the reaction mixture to prevent it from freezing on the flask
wall. The characteristic yellow color of p-TolSCl in the reaction
solution dissipated rapidly within a few seconds, indicating depletion
of p-TolSCl. After the donor was completely consumed according
to TLC analysis (about 5 min at -78 °C), a solution of acceptor
(0.060 mmol) in CH2Cl2 (0.2 mL) was slowly added dropwise via
a syringe. The reaction mixture was warmed to -10 °C under
stirring in 2 h. Then, the mixture was diluted with CH2Cl2 (20 mL)
and filtered over Celite. The Celite was further washed with CH2-
Cl2 until no organic compounds were observed in the filtrate by
TLC. All CH2Cl2 solutions were combined and washed twice with
a saturated aqueous solution of NaHCO3 (20 mL) and twice with
water (10 mL). The organic layer was collected and dried over
Na2SO4. After removal of the solvent, the desired disaccharide was
purified from the reaction mixture via silica gel flash chromatog-
raphy.
p-Tolyl 3,4,6-Tri-O-benzyl-â-D-galactopyranosyl-(1 f 3)-4,6-
benzylidene-2-(2,2,2-tri-chloroethoxycarbonylamino)-2-deoxy-
1-thio-â-D-galactopyranoside (13). Compound 12â (1.7 g, 1.81
mmol) was dissolved in a mixture of CH2Cl2/MeOH (25 mL each),
and 1 M NaOMe (5.4 mL, 5.4 mmol) was added at room
temperature. The mixture was heated at reflux for 4 h under N2
and then was neutralized with concd HCl until the pH was around
7. The mixture was concentrated and then diluted with CH2Cl2 (200
mL). The organic phase was washed with saturated aqueous solution
of NaHCO3, 10% HCl, and water and then dried over Na2SO4,
filtered, and concentrated. Silica gel column chromatography (3:
1:1 hexanes-/EtOAc-/CH2Cl2) afforded p-tolyl 3,4,6-tri-O-benzyl-
â-D-galactopyranosyl-(1 f 3)-4,6-benzylidene-2-azido-2-deoxy-1-
thio-â-D-galactopyranoside (S6) as a white solid (1.5 g, quantitative).
1H NMR (600 MHz, CDCl3): d 2.32 (s, 3H, SPhCH3), 2.52 (s,
1H, OH), 3.35 (s, br, 1H, H-5), 3.46 (dd, 1H, J2′,3′ ) 9.6 Hz, J3′,4′
) 3.0 Hz, H-3′), 3.51-3.61 (m, 4H, H-3, H-5′, H-6a′, H-6b′), 3.78
(dd, 1H, J1,2 ) 10.2 Hz, H-2), 3.85 (d, 1H, J3.4 ) 3.0 Hz, H-4′),
3.86-3.89 (dd, 1H, J ) 1.8, 12.0 Hz, H-6a), 3.96 (t, 1H, J ) 9.6
Hz, H-2′), 4.22 (d, 1H, J3′,4′ ) 3.0 Hz, H-4), 4.31 (dd, 1H, J ) 1.8,
12.0 Hz, H-6b), 4.35 (d, 1H, J1,2 ) 10.2 Hz, H-1), 4.42, 4.46 (2d,
2H, J ) 12.0 Hz, CH2Ph), 4.48 (d, 1H, J1′,2′ ) 9.6 Hz, H-1′), 4.59,
4.72, 4.77, 4.90 (4d, 4H, CH2Ph), 5.45 (s, 1H, CHPh), 6.98-7.08
(m, 2H), 7.25-7.43 (m, 20H, aromatic), 7.58-7.68 (m, 2H); 13C
NMR (150 MHz, CDCl3): d 21.5, 60.2, 69.3, 69.4, 70.3, 71.4, 73.3,
73.6, 73.7, 74.3, 74.9, 75.4, 80.4, 82.1, 85.7, 101.3, 105.4, 126.2,
127.0, 127.9, 128.98, 127.99, 128.2, 128.3, 128.5, 128.6, 128.7,
128.8, 129.3, 130.1, 135.0, 138.0, 138.1, 138.5, 138.6, 138.9;
HRMS: [M + Na]+ C47H49N3NaO9S calcd 854.3087, obsd
854.3085. p-Tolyl 3,4,6-tri-O-benzyl-â-D-galactopyranosyl-(1 f 3)-
4,6-benzylidene-2-azido-2-deoxy-1-thio-â-D-galactopyranoside (S6)
(1.3 g, 1.56 mmol), 1,3-propanedithiol (1.57 mL, 15.6 mmol), and
Et3N (1.10 mL, 15.6 mmol) were dissolved in a mixture of CH2-
Cl2/MeOH (10 mL each). The mixture was heated at reflux
overnight under N2 and then concentrated. The resulting residue
was diluted with CH2Cl2 (200 mL) and then washed with a saturated
aqueous solution of NaHCO3 and water, dried over Na2SO4, filtered,
and concentrated. Silica gel column chromatography (20:1 CH2-
Cl2/MeOH) afforded p-tolyl 3,4,6-tri-O-benzyl-â-D-galactopyrano-
syl-(1 f 3)-4,6-benzylidene-2-amino-2-deoxy-1-thio-â-D-galacto-
pyranoside (S7) as a white solid (1.07 g, 85%). 1H NMR (600 MHz,
CDCl3): δ 2.32 (s, 4H, SPhCH3, OH), 3.25 (t, 1H, J ) 9.6 Hz,
p-Tolyl 2-O-Benzoyl-3,4,6-tri-O-benzyl-â-D-galactopyranosyl-
(1 f 3)-2-azido-4,6-O-benzylidene-2-deoxy-1-thio-â-D-galacto-
pyranoside (12â) and p-Tolyl 2-O-Benzoyl-3,4,6-tri-O-benzyl-
R-D-galactopyranosyl-(1 f 3)-2-azido-4,6-O-benzylidene-2-
deoxy-1-thio-â-D-galactopyranoside (12R). Compounds 12â and
12R were synthesized from donor 8 and acceptor 6 in 50-70 and
10-20% yields, respectively, following the general procedure of
single step glycosylation. When CH3CN (100 µL) was used instead
of diethyl ether to dissolve the AgOTf, the formation of disaccharide
12R can be suppressed to a negligible amount with 72% yield of
the desired â disaccharide 12â. For 12â: [R]D -28.5 (c ) 4.3,
1
CH2Cl2); H NMR (600 MHz, CDCl3): δ 2.24 (s, 3H, SPhCH3),
3.31 (s, 1H, H-5), 3.55-3.65 (m, 6H, H-2, H-3, H-3′, H-5′, H-6a′,
H-6b′), 3.84 (d, 1H, J ) 10.8 Hz, H-6a), 3.96 (d, 1H, J3′,4′ ) 2.4
Hz, H-4′), 4.24-4.27 (m, 2H, H-4, H-6b), 4.30 (d, 1H, J1,2 ) 9.6
Hz, H-1), 4.44-4.47 (m, 3H, CH2Ph), 4.59-4.62 (m, 2H, J ) 12.0
Hz, CH2Ph), 4.79 (d, 1H, J1′,2′ ) 7.8 Hz, H-1′), 4.98 (d, 1H, J )
12.0 Hz, CH2Ph), 5.37 (s, 1H, CHPh), 5.62 (t, 1H, J1′,2′ ) 7.8 Hz,
H-2′), 6.83-6.92 (m, 2H), 7.10-7.18 (m, 5H, aromatic), 7.23-
7.41 (m, 17H, aromatic), 7.43-7.52 (m, 2H), 7.49-7.59 (m, 1H),
7.94-8.04 (m, 2H); 13C NMR (150 MHz, CDCl3): δ 21.4, 59.7,
69.2, 69.3, 70.1, 71.7, 72.0, 72.6, 73.7, 74.2, 74.6, 74.9, 79.3, 80.3,
85.8, 100.8, 102.3, 126.2, 126.7, 127.8, 127.9, 128.0, 128.1, 128.2,
128.4, 128.5, 128.6, 128.7, 128.9, 129.9, 130.0, 130.2, 133.1, 134.5,
137.6, 137.9, 138.0, 138.5, 138.6, 165.5; HRMS: [M + Na]+
C54H53N3NaO10S calcd 958.3349, obsd 958.3365. gHMQC (without
H-2), 3.37 (s, 1H, H-5), 3.37-3.39 (dd, 1H, J2′,3′ ) 9.6 Hz, J3′,4′
)
3.0 Hz, H-3′), 3.53 (dd, 1H, J2,3 ) 10.2 Hz, J3,4 ) 3.0 Hz, H-3),
3.55-3.59 (m, 3H, H-5′, H-6a′, H-6b′), 3.86 (d, 1H, J3′,4′ ) 3.0
Hz, H-4′), 3.86 (d, 1H, J ) 12.0 Hz, H-6a), 3.95 (t, 1H, J ) 9.6
Hz, H-2′), 4.16 (d, 1H, J3.4 ) 3.0 Hz, H-4), 4.29 (d, 1H, J ) 12.0
Hz, H-6b), 4.35 (d, 1H, J1,2 ) 9.6 Hz, H-1), 4.43-4.44 (m, 3H,
J1′,2′ ) 10.2 Hz, H-1′, CH2Ph), 4.57, 4.65, 4.68, 4.86 (4d, 4H, J )
12.0 Hz, CH2Ph), 5.43 (s, 1H, CHPh), 6.95-7.08 (m, 2H), 7.23-
7.42 (m, 20H, aromatic), 7.50-7.58 (m, 2H); 13C NMR (100 MHz,
1
1
1H decoupling): JC1′,H1′ ) 160.9 Hz, JC1,H1 ) 159.9 Hz; For
J. Org. Chem, Vol. 72, No. 17, 2007 6415

Wang et al.
CDCl3): δ 21.4, 49.7, 69.0, 69.6, 70.3, 71.5, 72.7, 73.0, 73.7, 74.2,
74.7, 75.4, 82.4, 83.8, 88.4, 101.1, 106.1, 126.6, 126.9, 127.79,
127.83, 127.9, 128.0, 128.2, 128.4, 128.5, 128.66, 128.68, 129.1,
129.9, 134.3, 138.08, 138.14, 138.3, 138.5, 138.6. HRMS: [M +
Na]+ C47H51NNaO9S calcd 828.3182, obsd 828.3182. p-Tolyl 3,4,6-
tri-O-benzyl-â-D-galactopyranosyl-(1 f 3)-4,6-benzylidene-2-
amino-2-deoxy-1-thio-â-D-galactopyranoside (S7) (1.06 g, 1.31
mmol) and solid NaHCO3 (0.22 g, 2.62 mmol) were put into THF
(16 mL), and then TrocCl (0.214 mL, 1.57 mmol) was added. The
mixture was stirred at room temperature under N2 for 4 h and
filtrated. The filtrate was concentrated and then diluted with CH2-
Cl2 (100 mL). The mixture was washed with water and brine, dried
over Na2SO4, filtered, and concentrated. Silica gel column chro-
matography (2:1 hexanes-/EtOAc) afforded 13 as a white solid
(1.2 g, 93%); [R]D -13.6 (c ) 1, CH2Cl2); 1H NMR (600 MHz,
CDCl3): δ 2.32 (s, 3H, SPhCH3), 3.34 (d, 1H, J2′,3′ ) 7.8 Hz, J3′,4′
) 3.0 Hz, H-3′), 3.40 (s, 1H, H-5), 3.48-3.61 (m, 3H, H-5′, H-6a′,
H-6b′), 3.65 (dd, 1H, J1,2 ) 10.2 Hz, JNH,2 ) 7.2 Hz, H-2), 3.82
(d, 1H, J3′,4′ ) 3.0 Hz, H-4′), 3.87 (d, 1H, J ) 12.0 Hz, H-6a),
3.92 (t, 1H, J ) 7.8 Hz, H-2′), 4.24-4.29 (m, 3H, H-3. H-4, H-6a),
4.35 (d, 1H, J1′,2′ ) 7.8 Hz, H-1′), 4.46 (s, 2H, CH2CCl3), 4.58 (d,
1H, J ) 12.0 Hz, CH2Ph), 4.66-4.71 (m, 3H, J ) 12.0 Hz, CH2-
topyranoside (S9) (3 g, 10.4 mmol) and dibutyltin oxide (2.6 g,
10.4 mmol) were put into MeOH (45 mL). The mixture was heated
at reflux for 2 h and then concentrated to dryness. DMF (30 mL)
was added to the resulting residue, p-methoxy benzyl chloride
(PMBCl, 1.5 mL, 10.4 mmol), and CsF (1.67 g, 10.4 mmol), which
were then stirred under N2 at 50 °C for 2 days and concentrated to
dryness. Silica gel column chromatography (1:2 hexanes/EtOAc)
afforded p-tolyl 3-O-p-methoxylbenzyl-1-thio-â-D-galactopyrano-
1
side (S10) as a white solid (2.34 g, 55% for two steps). H NMR
(600 MHz, CD3OD): δ 2.20 (s, 3H, SPhCH3), 3.27 (dd, 1H, J2,3
) 9.6 Hz, J3,4 ) 3.0 Hz, H-3), 3.35-3.38 (m, 1H, H-5), 3.58-
3.65 (m, 3H, J1,2 ) 10.2 Hz, H-2, H-6a, H-6b), 3.67 (s, 3H, OCH3),
3.94 (d, 1H, J3,4 ) 3.0 Hz, H-4), 4.41 (d, 1H, J1,2 ) 10.2 Hz, H-1),
4.51, 4.58 (2d, 2H, J ) 11.4 Hz, CH2PhOCH3), 6.72-6.82 (m,
2H), 6.96-7.05 (m, 2H), 7.20-7.28 (m, 2H), 7.30-7.38 (m, 2H);
13C NMR (100 MHz, CD3OD): δ 21.3, 55.76, 55.81, 62.7, 67.6,
70.3, 72.5, 80.5, 83.5, 90.8, 114.8, 130.64, 130.68, 130.8, 130.9,
131.9, 132.1, 133.1, 133.2, 138.6, 160.9. ESI-MS [M + Na]+
C21H26NaO6S calcd 429.2, obsd 429.3. p-Tolyl 3-O-p-methoxyl-
benzyl-1-thio-â-D-galactopyranoside (S10) (3.4 g, 8.36 mmol) was
dissolved in DMF (50 mL), and the solution was cooled to 0 °C.
NaH (1.34 g, 60% NaH in mineral oil, 33.44 mmol) was added in
portions, followed by the addition of BnBr (4 mL, 33.44 mmol).
The mixture was stirred at room temperature under N2 overnight
and then diluted with EtOAc (250 mL). The mixture was washed
with saturated NaHCO3 and water and then dried over Na2SO4,
filtered, and concentrated. Silica gel column chromatography (8:1
hexanes/EtOAc) afforded p-tolyl 2,4,6-tri-O-benzyl-3-O-p-meth-
oxylbenzyl-1-thio-â-D-galactopyranoside (14) as a white solid (4.5
g, 80%); [R]D +3.2 (c ) 1, CH2Cl2); 1H NMR (600 MHz,
CDCl3): δ 2.27 (s, 3H, SPhCH3), 3.56-3.65 (m, 4H, H-3, H-5,
H-6a, H-6b), 3.77 (s, 3H, OCH3), 3.87 (t, 1H, J ) 9.6 Hz, H-2),
3.93 (d, 1H, J3.4 ) 2.4 Hz, H-4), 4.40, 4.45, 4.58, 4.62, 4.65, 4.72,
4.78, 4.95 (8d, 8H, J ) 12.0 Hz, CH2PhOCH3, CH2Ph), 4.58 (d,
1H, J1,2 ) 10.2 Hz, H-1), 6.78-6.88 (m, 2H), 6.94-7.02 (m, 2H),
7.24-7.34 (m, 15H, aromatic), 7.35-7.45 (m, 2H), 7.40-7.49 (m,
2H); 13C NMR (150 MHz, CDCl3): δ 21.4, 55.5, 69.1, 72.7, 73.8,
73.9, 74.7, 75.9, 77.5, 84.2, 88.3, 114.1, 127.7, 127.96, 128.04,
128.1, 128.2, 128.4, 128.57, 128.59, 128.68, 129.5, 129.8, 130.5,
130.7, 132.5, 137.4, 138.2, 138.7, 139.1, 159.5. ESI-MS [M + Na]+
C42H44NaO6S calcd 699.3, obsd 699.5.
Compound 14 (0.3 g, 0.44 mmol) was dissolved in a mixture of
CH2Cl2/H2O (2.9 mL/0.15 mL), and the solution was cooled to 0
°C. 2,3-Dichloro 5,6-dicyano-1,4-benzoquinone (DDQ, 0.12 g, 0.53
mmol) was added, and the mixture was stirred at room temperature
for 3 h. The mixture was filtered and diluted with CH2Cl2 (30 mL),
and the organic phase was washed with H2O until the solution
became colorless. Silica gel column chromatography (4:1 hexanes-/
EtOAc) afforded 19 as a white solid (0.21 g, 85%); [R ]D -3.9 (c
) 3.3, CH2Cl2); 1H NMR (600 MHz, CDCl3): δ 2.21 (d, 1H, J )
5.4 Hz, OH), 2.30 (s, 3H, SPhCH3), 3.63-3.68 (m, 5H, H-2, H-3,
H-5, H-6a, H-6b), 3.89 (d, 1H, J3.4 ) 2.4 Hz, H-4), 4.44, 4.50 (2d,
2H, J ) 12.0 Hz, CH2Ph), 4.56 (d, 1H, J1,2 ) 9.0 Hz, H-1), 4.64
(d, 2H, J ) 12.0 Hz, CH2Ph), 4.73, 4.90 (2d, 2H, J ) 12.0 Hz,
CH2Ph), 6.98-7.08 (m, 2H), 7.28-7.37 (m, 15H), 7.42-7.52 (m,
2H); 13C NMR (150 MHz, CDCl3): δ 21.3, 68.8, 73.7, 75.1, 75.4,
75.9, 76.2, 77.5, 78.5, 87.9, 127.9, 127.98, 128.03, 128.05, 128.2,
128.53, 128.56, 128.60, 128.7, 129.8, 130.4, 132.2, 137.5, 138.0,
138.3, 138.7; HRMS: [M + Na]+ C34H36NaO5S calcd 579.2181,
obsd 579.2167.
Ph), 4.78, 4.88 (2d, 2H, J ) 12.0 Hz, CH2Ph), 5.07 (d, 1H, J1,2
)
10.2 Hz, H-1), 5.46 (s, 1H, CHPh), 5.52 (d, 1H, JNH,2 ) 7.2 Hz,
NH), 7.00-7.09 (m, 2H), 7.21-7.44 (m, 20H, aromatic), 7.50-
7.59 (m, 2H); 13C NMR (150 MHz, CDCl3): d 21.5, 51.8, 69.2,
69.5, 70.3, 71.3, 73.0, 73.4, 73.8, 74.2, 74.7, 74.8, 76.1, 77.3, 81.9,
84.3, 95.9, 101.1, 105.0, 127.0, 127.4, 127.9, 128.0, 128.0, 128.1,
128.2, 128.3, 128.5, 128.7, 128.76, 128.77, 129.2, 130.0, 134.5,
138.10, 138.12, 138.4, 138.6, 154.3; HRMS: [M + Na]+ C50H52-
Cl3NNaO11S calcd 1002.2224, obsd 1002.2208.
p-Tolyl 2,4,6-tri-O-Benzyl-1-thio-â-D-galactopyranoside (19).
â-D-Galactose pentaacetate (20 g, 51.2 mmol) and p-toluenethiol
(7.3 g, 58.8 mmol) were dissolved in CH2Cl2. (400 mL). Boron
trifluoride etherate (20.15 mL, 153.6 mmol) was added dropwise
at 0 °C, and the mixture was stirred under N2 at room temperature
for 20 h. The mixture was diluted with CH2Cl2 (450 mL) and
washed with saturated NaHCO3, dried over Na2SO4, filtered, and
concentrated. Silica gel column chromatography (2:1 hexanes/
EtOAc) afforded p-tolyl 2,3,4,6-tetra-O-acetyl-1-thio-â-D-galacto-
pyranoside (S8) as a white solid (21.2 g, 91%). 1H NMR (600 MHz,
CDCl3): δ 1.98, 2.05, 2.10, 2.12 (s, 12H, 4 × COCH3), 2.35 (s,
3H, SPhCH3), 3.92 (t, 1H, J ) 6.6 Hz, H-5), 4.10-4.20 (m, 2H,
H-6a, H-6b), 4.66 (d, 1H, J1,2 ) 10.2 Hz, H-1), 5.04 (dd, 1H, J2,3
) 9.6 Hz, J3,4 ) 3.0 Hz, H-3), 5.22 (t, 1H, J ) 10.2 Hz, H-2), 5.41
(d, 1H, J3,4 ) 3.0 Hz, H-4), 7.08-7.16 (m, 2H), 7.40-7.46 (m,
2H); 13C NMR (150 MHz, CDCl3): δ 20.82, 20.86, 20.90, 21.1,
21.4, 61.8, 67.4, 67.4, 67.5, 72.2, 74.5, 87.1, 128.8, 129.9, 133.3,
138.7, 160.74 169.7, 170.3, 170.4, 170.6. ESI-MS [M + Na]+
C21H26NaO9S calcd 477.1, obsd 477.3. Comparison of the NMR
data with those reported in the literature63 confirmed its identity.
p-Tolyl 2,3,4,6-tetra-O-acetyl-1-thio-â-D-galactopyranoside (S8)
(11.5 g, 25.3 mmol) was dissolved in a mixture of CH2Cl2/MeOH
(100 mL/70 mL), and 5.14 M NaOMe (2.4 mL, 12.7 mmol) was
added. The mixture was stirred at room temperature for 6 h under
N2 and then was neutralized with Amberlite IR-120 and concen-
trated to dryness. Silica gel column chromatography (10:1 CH2-
Cl2/MeOH) afforded p-tolyl 1-thio-â-D-galactopyranoside (S9) as
1
a white solid (7.2 g, quantitative). H NMR (600 MHz, CD3OD):
δ 2.28 (s, 3H, SPhCH3), 3.47 (dd, 1H, J2,3 ) 9.6 Hz, J3.4 ) 3.0 Hz,
H-3), 3.51 (t, 1H, J ) 6.6 Hz, H-5), 3.55 (t, 1H, J ) 9.6 Hz, H-2),
3.67-3.75 (m, 2H, H-6a, H-6b), 3.87 (d, 1H, J3.4 ) 3.0 Hz, H-4),
4.49 (d, 1H, J1,2 ) 9.6 Hz, H-1), 7.05-7.12 (m, 2H), 7.40-7.47
(m, 2H); 13C NMR (150 MHz, CD3OD): d 19.9, 61.4, 69.2, 69.8,
75.1, 79.4, 89.5, 129.4, 130.9, 131.7, 137.2. ESI-MS [M + Na]+
C13H18NaO5S calcd 309.1, obsd 309.1. p-Tolyl 1-thio-â-D-galac-
3-Azidopropyl 2,3,6-Tri-O-benzyl-â-D-galactopyranosyl-(1 f
4)-2,3,6-tri-O-benzyl-â-D-glucopyranoside (15). D-Lactose (5 g,
13.87 mmol) was dissolved in pyridine (30 mL), and then BzCl
(20 mL, 172 mmol) was added at 0 °C. The mixture was stirred at
room temperature under N2 overnight and then diluted with CH2-
Cl2 (400 mL). The mixture was washed with saturated NaHCO3
and water and then dried over Na2SO4, filtered, and concentrated.
The resulting residue was dissolved in CH2Cl2 (30 mL), and the
solution was cooled to -10 °C. HBr in acetic acid (60 mL, 33%
(63) Tai, C.-A.; Kulkarni, S. S.; Hung, S.-C. J. Org. Chem. 2003, 68,
8719.
6416 J. Org. Chem., Vol. 72, No. 17, 2007

Synthesis of Carbohydrate Antigen Globo-H
w/w, 104 mmol) was added, and the mixture was stirred at room
temperature under N2 for 5 h. The mixture was diluted with CH2-
Cl2 (200 mL) and poured onto crushed ice in saturated NaHCO3
(400 mL). The organic phase was separated and washed again with
saturated NaHCO3 until the pH was about 7 and then dried over
Na2SO4, filtered, and concentrated. The resulting residue (2 g, 1.76
mmol), 1-bromo propanol (2.3 mL, 26.4 mmol), and freshly
activated molecular sieve MS 4 Å (300 mg) were put into a 100
mL round-bottomed flask containing CH2Cl2 (20 mL), and the
mixture was stirred at room temperature for 30 min. AgOTf (0.54
g, 2.11 mmol) was added, and the mixture was stirred at room
temperature for 1 h. The mixture was diluted with CH2Cl2 (100
mL) and filtered. The filtrate was washed with saturated aqueous
NaHCO3 and H2O. The organic layer was dried over Na2SO4,
filtered, and concentrated. Silica gel column chromatography (3:1
hexanes/EtOAc) afforded 3-bromopropyl 2,3,4,6-tetra-O-benzoyl-
â-D-galactopyranosyl-(1 f 4)-2,3,6-tri-O-benzoyl-â-D-glucopyra-
(dd, 1H, J ) 4.8, 12.0 Hz, H-6b), 3.92-3.96 (m, 1H, CH2N3), 4.27
(d, 1H, J1′,2′ ) 7.8 Hz, H-1′), 4.34 (d, 1H, J1,2 ) 7.8 Hz, H-1); 13
C
NMR (150 MHz, CD3OD): δ 29.0, 48.2, 60.7, 61.3, 66.4, 69.1,
71.4, 73.5, 73.6, 75.2, 75.3, 75.9, 79.4, 103.1, 103.9. ESI-MS [M
+ Na]+ C15H27NaN3O11 calcd 448.2, obsd 448.2. The mixture of
3-azidopropyl â-D-galactopyranosyl-(1 f 4)-â-D-glucopyranoside
(S13) (0.5 g, 1.17 mmol), camphorsulfonic acid (0.14 g, 0.59 mmol),
benzaldehyde dimethylacetal (0.2 mL, 1.35 mmol), and DMF (3
mL) were stirred at room temperature under N2 overnight. The
mixture was neutralized with solid NaHCO3 (0.98 g, 1.17 mmol)
and then concentrated to dryness. Silica gel column chromatography
(8:1 CH2Cl2/MeOH) afforded 3-azidopropyl 4,6-O-benzylidene-â-
D-galactopyranosyl-(1 f 4)-â-D-glucopyranoside64 (S14) as a white
1
solid (0.49 g, 81%). H NMR (600 MHz, CD3OD): δ 1.80 (m,
2H, CH2CH2CH2N3), 3.21 (t, 1H, J ) 7.8 Hz, H-2′), 3.34-3.39
(m, 3H, H-5, OCH2CH2CH2N3), 3.49-3.62 (m, 6H, H-2, H-3, H-6a,
H-3′, H-5′, CH2N3), 3.84-3.89 (m, 3H, H-4, H-6b, CH2N3), 4.05
(d, 1H, J ) 11.4 Hz, H-6a′), 4.11-4.13 (m, 2H, H-4′, H-6b′), 4.21
(d, 1H, J1′,2′ ) 7.8 Hz, H-1′), 4.40 (d, 1H, J1,2 ) 7.8 Hz, H-1), 5.52
(s, 1H, CHPh), 7.27-7.48 (m, 5H, aromatic); 13C NMR (100 MHz,
CD3OD): δ 30.3, 49.4, 61.8, 67.7, 68.29, 68.33, 70.3, 71.8, 73.5,
74.8, 76.3, 76.5, 77.3, 80.1, 102.2, 104.4, 104.9, 127.6, 129.2, 130.0,
139.6. ESI-MS [M + Na]+ C22H31NaN3O11 calcd 536.2, obsd 536.3.
3-Azidopropyl 4,6-O-benzylidene-â-D-galactopyranosyl-(1 f 4)-
â-D-glucopyranoside (S14) (2 g, 3.89 mmol) was dissolved in DMF
(25 mL), and the solution was cooled to 0 °C. NaH (0.93 g, 60%
NaH in mineral oil, 23.34 mmol) was added in portions, followed
by the addition of BnBr (2.8 mL, 33.44 mmol). The mixture was
stirred at room temperature under N2 for 6 h and then diluted with
EtOAc (250 mL). The mixture was washed with saturated aqueous
NaHCO3 and water and then dried over Na2SO4, filtered, and
concentrated. Silica gel column chromatography (6:1 hexanes/
EtOAc) afforded 3-azidopropyl 2,3-di-O-benzyl-4,6-O-benzylidene-
â-D-galactopyranosyl-(1 f 4)-2,3,6-tri-O-benzyl-â-D-glucopyra-
noside53 (S15) as a white solid (3 g, 80%); [R]D +176.4 (c, 0.56,
CH2Cl2); [R]D +16.1 (c ) 1, CHCl3); 1H NMR (600 MHz,
CDCl3): δ 1.88 (m, 2H, CH2CH2CH2N3), 2.93 (s, 1H, H-5′), 3.33-
3.39 (m, 4H, H-3, H-5, OCH2CH2CH2N3), 3.42 (t, 1H, J ) 7.8
Hz, H-2′), 3.60-3.64 (m, 2H, H-3′, CH2N3), 3.68-3.70 (d, 1H, J
) 10.8 Hz, H-6a), 3.74-3.77 (t, 1H, J ) 7.8 Hz, H-2), 3.84 (d,
1H, J3,4 ) 12.0 Hz, H-4), 3.86-3.89 (dd, 1H, J5′,6a′ ) 4.2 Hz, J6a′,6b′
) 10.8 Hz, H-6a′), 3.96-3.98 (m, 2H, H-6b, CH2N3), 4.02 (d, 1H,
J3′,4′ ) 3.0 Hz, H-4′), 4.20 (d, 1H, J ) 12.0 Hz, H-6b′), 4.32, (d,
1H, J ) 12.0 Hz, CH2Ph), 4.36 (d, 1H, J1′,2′ ) 7.8 Hz, H-1′), 4.44
(d, 1H, J1,2 ) 7.8 Hz, H-1), 4.54 (d, 1H, J ) 12.0 Hz, CH2Ph),
4.72-4.85 (m, 7H, CH2Ph), 5.19, 5.46 (2d, 2H, J ) 12.0 Hz, CH2-
Ph), 7.17-7.52 (m, 30H, aromatic); 13C NMR (150 MHz, CDCl3):
δ 29.47, 48.56, 66.57, 66.59, 66.78, 68.44, 69.19, 71.85, 73.22,
73.88, 75.33, 75.35, 75.34, 76.07, 77.80, 79.05, 79.86, 82.06, 83.30,
101.61, 103.09, 103.80, 126.81, 127.55, 127.66, 127.70, 127.87,
127.95, 127.99, 128.15, 128.33, 128.38, 128.45, 128.48, 128.59,
128.61, 128.87, 129.10, 138.32, 138.65, 138.72, 138.84, 139.09,
139.13. ESI-MS [M + Na]+ C57H61NaN3O11 calcd 986.4, obsd
986.7. 3-Azidopropyl 2,3-di-O-benzyl-4,6-O-benzylidene-â-D-ga-
lactopyranosyl-(1 f 4)-2,3,6-tri-O-benzyl-â-D-glucopyranoside (S15)
(0.6 g, 0.62 mmol) and NaBH3CN (0.35 g, 5.58 mmol) were
dissolved in THF (15 mL) and cooled to 0 °C. A solution of HCl
in ether (2 M, 3 mL) was added, and the mixture was stirred at
room temperature for 3 h and then concentrated to dryness. The
obtained residue was diluted with CH2Cl2 and washed with 10%
HCl and water and then dried over Na2SO4, filtered, and concen-
trated. Silica gel column chromatography (3:1 hexanes/EtOAc)
afforded 15 as a white solid (0.53 g, 89%); [R]D +16.1 (c ) 1,
1
noside (S11) as a white solid (1.6 g, 65% for 3 steps). H NMR
(600 MHz, CDCl3): δ 1.96 (m, 2H, OCH2CH2CH2N3), 3.27 (m,
2H, OCH2CH2CH2N3), 3.64 (m, 1H, CH2N3), 3.73-3.81 (m, 2H,
H-5′, H-6a′), 3.88-3.98 (m, 3H, H-5, H-6b′, CH2N3), 4.32 (t, 1H,
J ) 9.6 Hz, H-4), 4.56 (dd, 1H, J ) 4.2, 12.0 Hz, H-6a), 4.67 (d,
1H, J ) 12.0 Hz, H-6b), 4.75 (d, 1H, J1,2 ) 7.8 Hz, H-1), 4.96 (d,
1H, J1′,2′ ) 7.8 Hz, H-1′), 5.45 (dd, 1H, J2′,3′ ) 10.2 Hz, J3′,4′ ) 3.0
Hz, H-3′), 5.51 (t, 1H, J ) 9.6 Hz, H-2), 5.78-5.80 (m, 2H, H-2′,
H-4′), 5.87 (t, 1H, J ) 9.6 Hz, H-3), 7.14-8.04 (m, 35H, aromatic);
13C NMR (100 MHz, CDCl3): δ 30.1, 32.3, 61.1, 62.4, 67.5, 69.9,
71.4, 71.78, 71.82, 72.83, 73.0, 76.0, 101.1, 101.4, 128.3, 128.4,
128.56, 128.63, 128.8, 129.2, 129.4, 129.5, 129.57, 129.62, 129.68,
129.74, 130.0, 133.2, 133.3, 133.4, 133.6, 164.8, 165.2, 165.3,
165.4, 165.5, 165.8. ESI-MS [M + Na]+ C64H55NaBrO18 calcd
1213.3, obsd 1213.6. 3-Bromopropyl 2,3,4,6-tetra-O-benzoyl-â-D-
galactopyranosyl-(1 f 4)-2,3,6-tri-O-benzoyl-â-D-glucopyranoside
(S11) (1.2 g, 1 mmol) and NaN3 (0.66 g, 10 mmol) were dissolved
in DMF (10 mL). The mixture was stirred at 60 °C for 30 h and
then concentrated. The resulting residue was diluted with EtOAc
(200 mL), washed with H2O, and then dried over Na2SO4, filtered,
and concentrated. Silica gel column chromatography (3:1 hexanes/
EtOAc) afforded compound 3-azidopropyl 2,3,4,6-tetra-O-benzoyl-
â-D-galactopyranosyl-(1 f 4)-2,3,6-tri-O-benzoyl-â-D-glucopyra-
1
noside (S12) as a white solid (1.04 g, 90%). H NMR (600 MHz,
CDCl3): δ 1.72 (m, 2H, CH2CH2CH2N3), 3.18 (m, 2H, OCH2CH2-
CH2N3), 3.54 (m, 1H, CH2N3), 3.71-3.78 (m, 2H, H-5′, H-6a′),
3.86-3.95 (m, 3H, H-5, H-6b′, CH2N3), 4.29 (t, 1H, J ) 9.0 Hz,
H-4), 4.53 (dd, 1H, J ) 4.2, 12.0 Hz, H-6a), 4.64 (d, 1H, J ) 12.0
Hz, H-6b), 4.71 (d, 1H, J1,2 ) 7.8 Hz, H-1), 4.93 (d, 1H, J1′,2′
)
7.8 Hz, H-1′), 5.43 (dd, 1H, J2′,3′ ) 10.2 Hz, J3′,4′ ) 3.0 Hz, H-3′),
5.49 (t, 1H, J ) 7.8 Hz, H-2), 5.75-5.78 (m, 2H, H-2′, H-4′), 5.85
(t, 1H, J ) 9.6 Hz, H-3), 7.14-8.12 (m, 35H, aromatic); 13C NMR
(100 MHz, CDCl3): δ 29.1, 48.0, 61.2, 62.5, 66.8, 67.7, 70.0, 71.5,
71.9, 72.0, 73.0, 73.2, 76.2, 101.2, 101.4, 128.4, 128.67, 128.71,
128.76, 128.82, 128.99, 129.4, 129.6, 129.66, 129.74, 129.77,
129.84, 129.86, 129.93, 130.18, 130.37, 133.40, 133.5, 133.6, 133.8,
133.9, 165.0, 165.4, 165.58, 165.60, 165.8, 166.0. ESI-MS [M +
Na]+ C64H55NaN3O18 calcd 1176.4, obsd 1176.8. 3-Azidopropyl
2,3,4,6-tetra-O-benzoyl-â-D-galactopyranosyl-(1 f 4)-2,3,6-tri-O-
benzoyl-â-D-glucopyranoside (S12) (1 g, 0.86 mmol) was dissolved
in MeOH (16 mL), and 5.14 M NaOMe (1.67 mL, 8.6 mmol) was
added. The mixture was heated at reflux for 6 h under N2 and then
was neutralized with Amberlite IR-120 until the pH was around 7.
It was filtered and concentrated to dryness. Silica gel column
chromatography (4:1 CH2Cl2/MeOH) afforded 3-azidopropyl â-D-
galactopyranosyl-(1 f 4)-â-D-glucopyranoside (S13) as a white
1
1
CHCl3); H NMR (600 MHz, CDCl3): δ 1.86 (m, 2H, CH2CH2-
solid (0.36 g, 97%). H NMR (600 MHz, CD3OD): δ 1.85 (m,
CH2N3), 2.48 (s, 1H, OH), 3.30-3.41 (m, 6H, H-2′, H-3, H-5, H-5′,
OCH2CH2CH2N3), 3.46-3.49 (dd, 1H, J5,6a ) 5.4 Hz, J6a,6b ) 9.6
2H, CH2CH2CH2N3), 3.23 (t, 1H, J ) 7.8 Hz, H-2′), 3.38-3.40
(m, 1H, H-5), 3.40-3.58 (m, 7H, H-2, H-3, H-6a, H-3′, H-5′, OCH2-
CH2CH2N3), 3.60-3.64 (m, 1H, CH2N3), 3.68 (dd, 1H, J ) 4.8,
12.0 Hz, H-6a′), 3.76 (dd, 1H, J ) 7.8, 11.4 Hz, H-4), 3.80 (d, 1H,
J3′,4′ ) 3.0 Hz, H-4′), 3.83 (dd, 1H, J ) 3.6, 12.0 Hz, H-6b′), 3.88
(64) Yang, Z.-Q.; Puffer, E. B.; Pontrello, J. K.; Kiessling, L. L.
Carbohydr. Res. 2002, 337, 1605.
J. Org. Chem, Vol. 72, No. 17, 2007 6417

Wang et al.
Hz, H-6a), 3.55-3.70 (m, 5H, H-2, H-3′, H-6a′, H-6b, CH2N3),
3.79-3.81 (dd, 1H, J5′,6a′ ) 4.2 Hz, J6a′,6b′ ) 10.8 Hz, H-6b′), 3.94-
4.01 (m, 3H, H-4, H-4′, CH2N3), 4.34-4.45 (m, 5H, J1,2 ) 7.8 Hz,
J1′,2′ ) 8.4 Hz, H-1, H-1′, CH2Ph), 4.54, 4.64, 4.69 (3d, 3H, J )
12.0 Hz, CH2Ph), 4.73-4.79 (m, 4H, CH2Ph), 4.83, 4.99 (2d, 2H,
J ) 12.0 Hz, CH2Ph), 7.19-7.39 (m, 30H, aromatic); 13C NMR
(150 MHz, CDCl3): δ 29.6, 48.6, 66.4, 66.8, 68.5, 68.8, 72.3, 73.1,
73.4, 73.8, 75.36, 75.39, 75.6, 75.7, 76.8, 79.7, 81.4, 82.1, 83.2,
89.5, 102.9, 103.9, 127.6, 127.85, 127.88, 127.95, 127.99, 128.09,
128.12, 128.19, 128.26, 128.40, 128.45, 128.61, 128.67, 128.70,
128.80, 138.2, 138.5, 138.6, 138.88, 138.94, 139.4. ESI-MS [M +
Na]+ C57H63NaN3O11 calcd 988.5, obsd 988.8.
4.36 (m, 4H, J1′,2′ ) 7.8 Hz, H-1′, H-6b′′, CH2Ph), 4.44-4.52 (m,
5H, J1,2 ) 7.8 Hz, H-1, CH2Ph), 4.68-4.80 (m, 7H, CH2Ph), 4.85-
4.87 (m, 2H, CH2Ph), 5.04 (d, 1H, J1′′,2′′ ) 3.0 Hz, H-1′′), 5.07 (d,
1H, CH2Ph), 6.77-7.46 (m, 49H, aromatic); 13C NMR (150 MHz,
CDCl3): δ 29.5, 48.6, 55.5, 66.7, 67.9, 68.1, 68.4, 69.7, 72.3, 72.4,
73.26, 73.30, 73.4, 73.50, 74.0, 75.0, 75.13, 75.19, 75.3, 75.50,
75.52, 76.7, 77.4, 79.5, 79.7, 81.9, 82.9, 101.1, 103.1, 103.7, 113.8,
127.62, 127.66, 127.68, 127.72, 127.74, 127.76, 127.83, 127.84,
127.86, 127.89, 127.91, 128.11, 128.21, 128.37, 128.40, 128.42,
128.48, 128.50, 128.51, 128.52, 128.54, 128.56, 128.63, 128.80,
129.08, 138.26, 138.59, 138.66, 138.83, 138.86, 138.99, 139.01,
139.20, 139.33, 159.1; HRMS: [M + Na]+ C92H99N3NaO17 calcd
1540.6872, obsd 1540.6831. gHMQC (without 1H decoupling):
3-Azidopropyl 2,3-Di-O-benzoyl-6-O-benzyl-â-D-galactopy-
ranosyl-(1 f 4)-2,3,6-tri-O-benzoyl-â-D-glucopyranoside (21).
3-Azidopropyl 4,6-O-benzylidene-â-D-galactopyranosyl-(1 f 4)-
â-D-glucopyranoside (0.5 g, 0.97 mmol) was dissolved in pyridine
(20 mL), and then BzCl (1.1 mL, 9.7 mmol) was added at 0 °C.
The mixture was stirred at room temperature under N2 overnight
and then diluted with CH2Cl2 (100 mL). The mixture was washed
with a saturated aqueous solution of NaHCO3 and water and then
dried over Na2SO4, filtered, and concentrated. The mixture of the
resulting residue and NaBH3CN (0.6 g, 9.7 mmol) in THF (20 mL)
was cooled to 0 °C, and then a solution of HCl in ether (2 M) was
added until the solution was acidic. The mixture was stirred at room
temperature for 3 h and then concentrated to dryness. The resulting
residue was diluted with CH2Cl2 and washed with 10% aqueous
HCl and water and then dried over Na2SO4, filtered, and concen-
trated. Silica gel column chromatography (2:1 hexanes/EtOAc)
afforded 21 as a gel-like solid (0.7 g, 70% for two steps); [R]D
+47.9 (c ) 1, CH2Cl2); 1H NMR (600 MHz, CDCl3): δ 1.70 (m,
2H, CH2CH2CH2N3), 3.01-3.08 (m, 2H, H-6a′, H-6b′), 3.12-3.19
(m, 2H, OCH2CH2CH2N3), 3.45 (t, 1H, J ) 6.0 Hz, H-5′), 3.48-
3.52 (m, 1H, CH2N3), 3.81-3.87 (m, 2H, H-5, CH2N3), 4.17-4.26
(m, 4H, H-4, H-4′, CH2Ph), 4.42 (dd, 1H, J ) 4.8, 12.0 Hz, H-6a),
4.60 (dd, 1H, J ) 1.8, 12.0 Hz, H-6b), 4.65 (d, 1H, J1,2 ) 7.8 Hz,
H-1), 4.76 (d, 1H, J1′,2′ ) 7.8 Hz, H-1′), 5.12 (dd, 1H, J2′,3′ ) 10.5
Hz, J3′,4′ ) 3.0 Hz, H-3′), 5.37 (t, 1H, J ) 7.8 Hz, H-2), 5.69-
5.75 (m, 2H, H-3, H-2′), 7.20-8.02 (m, 30H, aromatic); 13C NMR
(100 MHz, CDCl3): δ 29.0, 48.0, 62.5, 66.6, 67.2, 67.5, 70.1, 72.0,
73.1, 73.1, 73.4, 73.5, 74.4, 76.4, 101.0, 101.4, 127.7, 128.0, 128.6,
129.0, 129.2, 129.3, 129.7, 129.81, 129.84, 129.91, 129.93, 129.98,
130.01, 133.29, 133.37, 133.47, 137.8, 165.2, 165.43, 165.45,
165.88, 165.93; HRMS: [M + Na]+ C57H53N3NaO16 calcd
1058.3324, obsd 1058.3315.
1
1
1JC1′′,H1′′ ) 169.0 Hz, JC1′,H1′ ) 160.1 Hz, JC1,H1 ) 160.0 Hz.
3-Azidopropyl 2,4,6-Tri-O-benzyl-R-D-galactopyranosyl-(1 f
4)-2,3,6-tri-O-benzyl-â-D-galactopyranosyl-(1 f 4)-2,3,6-tri-O-
benzyl-â-D-glucopyranoside (17). Compound 16 (0.51 g, 0.34
mmol) was dissolved in a mixture of CH2Cl2/H2O (4.9 mL/0.5 mL),
and the solution was cooled to 0 °C. DDQ (0.84 g, 0.37 mmol)
was added, and the mixture was stirred at room temperature for 4
h. The mixture was filtered and diluted with CH2Cl2 (100 mL),
and the organic phase was washed with H2O until the solution
became colorless. Silica gel column chromatography (4:1 hexanes/
EtOAc) afforded 17 as a white solid (0.37 g, 80%). [R]D +34.6 (c
) 1, CH2Cl2); 1H NMR (600 MHz, CDCl3): δ 1.87 (m, 2H, CH2-
CH2CH2), 3.17 (dd, 1H, J ) 4.8, 8.4 Hz, H-6a), 3.27-3.39 (m,
6H, H-2′, H-3, H-5, H-5′, OCH2), 3.44-3.62 (m, 6H, H-2, H-3′,
H-5′′, H-6b, H-6a′, CH2N3), 3.69-3.82 (m, 3H, H-2′′, H6a′′, H-6b′),
3.91-4.14 (m, 9H, H-4, H-4′, H-4′′, H-3′′, CH2N3, CH2Ph), 4.34-
4.39 (m, 3H, J1′,2′ ) 7.8 Hz, H-1′, H-6a′′, CH2Ph), 4.45 (d, 1H, J1,2
) 7.8 Hz, H-1), 4.47-4.54 (m, 4H, CH2Ph), 4.67-4.84 (m, 8H,
CH2Ph), 5.07 (d, 1H, J ) 12.0 Hz, CH2Ph), 5.10 (d, 1H, J1′′,2′′
)
3.0 Hz, H-1′′), 7.13-7.39 (m, 45H, aromatic); 13C NMR (150 MHz,
CDCl3): δ 29.5, 48.6, 66.8, 67.9, 68.0, 68.5, 69.5, 70.3, 72.4, 73.27,
73.33, 73.38, 73.43, 75.1, 75.31, 75.36, 75.47, 75.51, 75.53, 77.2,
77.9, 79.6, 81.8, 81.9, 83.2, 89.5, 99.9, 103.0, 103.8, 127.5, 127.74,
127.76, 127.78, 127.79, 127.85, 127.86, 127.88, 127.92, 127.95,
128.00, 128.02, 128.10, 128.27, 128.34, 128.35, 128.42, 128.44,
128.52, 128.55, 128.56, 128.58, 128.60, 128.71, 128.79, 138.27,
138.48, 138.57, 138.62, 138.82, 138.83, 138.93, 139.02, 139.6;
HRMS: [M + Na]+ C84H91N3NaO16 calcd 1420.6297, obsd
1420.6276.
p-Tolyl 2,3,4-Tri-O-benzyl-1-thio-â-L-fucopyranoside (18). L-
Fucose (10 g, 60.9 mmol) and DMAP (0.72 g, 6.01 mmol) were
dissolved in anhydrous pyridine (100 mL), and acetic anhydride
(40 mL) was added at room temperature in a period of 30 min.
The mixture was stirred at room temperature under N2 overnight
and then quenched with ethanol (20 mL) at 0 °C. The mixture was
concentrated, and the resulting residue was diluted with ethyl acetate
(300 mL), and washed with water, saturated NaHCO3, 10% aqueous
hydrochloric acid, and brine. The organic phase was dried over
Na2SO4 and then filtered and concentrated. Silica gel column
chromatography (2:1 hexanes-/EtOAc) afforded the 1,2,3,4-tetra-
O-acetyl-L-fucopyranoside as a white solid (21 g, quantitative, R/â
mixtures) with the R isomer (S16) as the major product. 1H NMR
(600 MHz, CDCl3): δ 1.01 (d, 3H, J5,6 ) 6.6 Hz, H-6), 1.86, 1.87,
2.01, 2.04 (4s, 12H, 4 × COCH3), 4.15 (m, 1H, H-5), 5.15 (d, 1H,
J1,2 ) 3.6 Hz, H-2), 5.16-5.20 (m, 2H, H-3, H-4), 6.18 (d, 1H,
J1,2 ) 3.6 Hz, H-1); 13C NMR (150 MHz, CDCl3): δ 16.0, 20.6,
20.7, 20.8, 21.0, 66.6, 67.3, 67.9, 70.6, 89.9, 169.2, 170.0, 170.2,
170.6. ESI-MS [M + Na]+ C14H20NaO9 calcd 355.1, obsd 355.3.
The obtained R/â mixture of 1,2,3,4-tetra-O-acetyl-L-fucopyranoside
(21 g) and p-toluenethiol (8.32 g, 67 mmol) were dissolved in CH2-
Cl2 (180 mL) and cooled to 0 °C. Boron trifluoride etherate (10.5
mL, 83 mmol) was added dropwise at 0 °C, and the mixture was
stirred under N2 at room temperature overnight. The mixture was
diluted with CH2Cl2 and washed with saturated aqueous NaHCO3
until the pH was around 7 and then dried over Na2SO4, filtered,
and concentrated. The obtained crude product was recrystallized
3-Azidopropyl 2,4,6-Tri-O-benzyl-3-O-p-methoxybenzyl-R-D-
galactopyranosyl-(1 f 4)-2,3,6-tri-O-benzyl-â-D-galactopyra-
nosyl-(1 f 4)-2,3,6-tri-O-benzyl-â-D-glucopyranoside (16). After
the donor 14 (400 mg, 0.59 mmol), acceptor 15 (540 mg, 0.56
mmol), and activated molecular sieve MS-4 Å (500 mg) were stirred
for 30 min at room temperature in a mixture solvent of Et2O (8
mL) and CH2Cl2 (16 mL), the mixture was cooled to -78 °C,
followed by the addition of AgOTf (456 mg, 1.77 mmol) in Et2O
(12 mL). The mixture was vigorously stirred for 10 min, then
p-TolSCl (93.7 µL, 0.59 mmol) was added, and the reaction mixture
was stirred for 2 h from -78 to -40 °C (see the General Procedure
for Single Step Preactivation Based Glycosylation for precautions).
The mixture was concentrated under vacuum to dryness. The
resulting residue was diluted with CH2Cl2 (100 mL), followed by
filtration. The organic phase was washed with saturated aqueous
NaHCO3 and H2O and then dried over Na2SO4, filtered, and
concentrated. Silica gel column chromatography (2:1 hexanes/
EtOAc) afforded 16 as a gel-like solid (702 mg, 82%); [R]D +37.3
1
(c ) 2.6, CH2Cl2); H NMR (600 MHz, CDCl3): δ 1.86 (m, 2H,
OCH2CH2CH2N3), 3.15 (dd, 1H, J ) 4.8, 8.4 Hz, H-6a), 3.28-
3.38 (m, 6H, H-2′, H-3, H-5, H-5′, OCH2CH2CH2N3), 3.47-3.50
(m, 2H, H-5′′, H-6b), 3.55-3.70 (m, 4H, H-2, H-3′, H-6a′, CH2N3),
3.76 (s, 3H, OCH3), 3.82 (m, 1H, H-6a′′), 3.93-3.98 (m, 3H, H-4,
H-4′, CH2N3), 4.02-4.07 (m, 5H, H-2′′, H-3′’, H-6b′, CH2Ph), 4.17
(dd, 1H, H-4′′), 4.21-4.28 (2d, 2H, J ) 12.0 Hz, CH2Ph), 4.33-
6418 J. Org. Chem., Vol. 72, No. 17, 2007

Synthesis of Carbohydrate Antigen Globo-H
by EtOAc/hexanes to give p-tolyl 2,3,4-tri-O-acetyl-1-thio-â-L-
in CH2Cl2 (1 mL). The mixture was stirred for 10 min at -78 °C,
and then p-TolSCl (12.5 µL, 78.60 µmol) was added into the
solution. The reaction mixture was stirred for 2 h from -78 to 10
°C and then was quenched with Et3N (40 µL) and concentrated
under vacuum to dryness. The resulting residue was diluted with
CH2Cl2 (30 mL), followed by filtration. The organic phase was
washed with a saturated aqueous solution of NaHCO3 and H2O
and then dried over Na2SO4, filtered, and concentrated. Silica gel
column chromatography (2:1 hexanes-/EtOAc) afforded 46.6 mg
of 20R (47%) and 22.4 mg of 20â (23%), respectively, as colorless
gel. For 20R: [R]D -18.0 (c ) 2.4, CH2Cl2); 1H NMR (600 MHz,
CDCl3): δ 0.42 (d, 3H, J ) 6.6 Hz, H-6′′′′′), 1.84 (m, 2H, OCH2-
CH2CH2N3), 2.80 (s, 1H), 3.19 (m, 1H), 3.27-3.39 (m, 7H), 3.46-
3.68 (m, 11H), 3.76-3.86 (m, 5H), 3.92-4.25 (m, 17H), 4.29-
4.59 (m, 18H), 4.64-4.87 (m, 13H), 4.94 (d, 1H, J1′′,2′′ ) 3.0 Hz,
H-1′′), 5.06 (d, 1H, J ) 11.4 Hz), 5.24 (d, 1H, J ) 11.4 Hz), 5.42
(s, 1H), 5.55 (d, 1H, J1′′′′′,2′′′′′ ) 3.6 Hz, H-1′′′′′), 7.00-7.45 (m,
80H, aromatic); 13C NMR (150 MHz, CDCl3): δ 16.1, 29.4, 29.9,
48.5, 54.4, 66.2, 66.6, 66.7, 67.7, 68.1, 68.4, 69.0, 69.2, 69.4, 72.0,
72.1, 72.5, 72.7, 72.9, 73.1, 73.22, 73.24, 73.28, 73.57, 73.63, 73.77,
73.9, 74.57, 74.67, 74.76, 74.78, 74.94, 75.13, 75.18, 75.27, 75.4,
76.2, 76.3, 76.8, 77.6, 78.6, 79.2, 79.7, 80.4, 81.5, 81.7, 82.0, 84.1,
95.8, 97.5, 100.8, 101.8, 102.6, 102.7, 102.8, 103.6, 126.6, 127.03,
127.06, 127.24, 127.28, 127.31, 127.41, 127.44, 127.55, 127.61,
127.67, 127.68, 127.70, 127.76, 127.79, 127.81, 127.93, 128.01,
128.02, 128.11, 128.16, 128.18, 128.20, 128.34, 128.38, 128.42,
128.45, 128.50, 128.56, 128.65, 128.68, 128.72, 128.76, 128.77,
129.1, 129.9, 137.9, 138.2, 138.3, 138.44, 138.45, 138.47, 138.67,
138.81, 138.94, 138.99, 139.1, 139.4, 139.7, 139.8, 154.0; HRMS:
[M + Na]+ C154H163Cl3N4O31 calcd 2692.0265, obsd 2692.0332.
1
fucopyranoside63 (S17) as a white solid (11.6 g, 48%). H NMR
(600 MHz, CDCl3): δ 1.15 (d, 3H, J5,6 ) 6.6 Hz, H-6), 1.90, 2.01,
2.07 (3s, 9H, 3 × COCH3), 2.26 (s, 3H, SPhCH3), 3.74 (m, 1H,
H-5), 4.58 (d, 1H, J1,2 ) 10.2 Hz, H-1), 4.98 (dd, 1H, J2,3 ) 9.6
Hz, J3,4 ) 3.0 Hz, H-3), 5.13 (t, 1H, J ) 9.6 Hz, H-2), 5.18 (d,
1H, J3,4 ) 3.0 Hz, H-4), 7.00-7.09 (m, 2H), 7.30-7.39 (m, 2H);
13C NMR (150 MHz, CDCl3): δ 16.7, 20.8, 20.9, 21.1, 21.3, 67.5,
70.5, 72.6, 73.2, 86.9, 129.3, 129.8, 133.0, 138.3, 169.6, 170.3,
170.8. ESI-MS [M + Na]+ C19H24NaO7S calcd 419.1, obsd 419.2.
p-tolyl 2,3,4-tri-O-acetyl-L-thio-â-L-fucopyranoside (S17) (9.2 g,
23.2 mmol) was dissolved in a mixture of CH2Cl2/MeOH (70 mL/
50 mL), and 1 M NaOMe (12 mL, 11.6 mmol) was added at room
temperature. The mixture was stirred for 2 h at room temperature
under N2, neutralized with Amberlite IR-120, concentrated, and
vacuum-dried. The obtained residue (6 g) was dissolved in DMF
(100 mL) and cooled to 0 °C. NaH (3.6 g, 60% NaH in mineral
oil, 88 mmol) was added in portions, followed by the addition of
BnBr (10.5 mL, 88 mmol) 30 min later. The mixture was stirred at
room temperature under N2 for 2 h and then diluted with EtOAc
(300 mL). The mixture was washed with saturated aqueous solution
of NaHCO3 and water and then dried over Na2SO4, filtered, and
concentrated. The obtained crude product was recrystallized by
EtOAc/hexanes to give 1837 as a white solid (9.4 g, 75% for two
1
steps); [R]D -9.4 (c ) 1, CH2Cl2); H NMR (600 MHz, CDCl3):
δ 1.25 (d, 3H, J5,6 ) 6.6 Hz, H-6), 2.29 (s, 3H, SPhCH3), 3.50 (m,
1H, H-5), 3.58 (dd, 1H, J2,3 ) 9.6 Hz, J3,4 ) 2.4 Hz, H-3), 3.62 (d,
1H, J3,4 ) 2.4 Hz, H-4), 3.89 (t, 1H, J ) 9.6 Hz, H-2), 4.55 (d,
1H, J1,2 ) 10.2 Hz, H-1), 4.66 (d, 1H, J ) 12.0 Hz, CH2Ph), 4.72-
4.81 (m, 4H, J ) 12.0 Hz, CH2Ph), 5.00 (d, 1H, J ) 12.0 Hz,
CH2Ph), 6.94-7.08 (m, 2H), 7.27-7.40 (m, 15H, aromatic), 7.44-
7.56 (m, 2H); 13C NMR (150 MHz, CDCl3): δ 17.6, 21.4, 73.1,
74.8, 75.8, 76.8, 77.4, 84.8, 88.1, 127.7, 127.8, 127.95, 127.97,
128.2, 128.4, 128.59, 128.62, 128.70, 129.78, 130.7, 132.4, 137.4,
138.6, 138.7, 139.0. ESI-MS [M + Na]+ C34H36NaO4S calcd 563.2,
obsd 563.5.
1
gHMQC (without 1H decoupling): JC1′′′′′,H1′′′′′ ) 171.9 Hz, 1JC1′′,H1′′
1
) 169.8 Hz, other four JC1,H1 ) 160.1, 160.1, 162.6, 162.6 Hz.
1
For 20â: [R]D -4.2 (c ) 1, CH2Cl2); H NMR (600 MHz,
CDCl3): δ 0.60 (d, 3H, J ) 6.6 Hz, H-6′′′′′), 1.85 (m, 2H, OCH2-
CH2CH2N3), 3.22-3.63 (m, 21H), 3.66-3.79 (m, 6H), 3.86-3.99
(m, 6H), 4.05-4.24 (m, 7H), 4.28-4.51 (m, 18H), 4.55-4.60 (m,
4H), 4.63-4.79 (m, 8H), 4.85-4.94 (m, 3H), 5.09-5.13 (m, 2H),
5.22 (d, 1H, J ) 12.0 Hz), 5.49 (s, 1H), 5.55 (d, 1H, J1′′′′′,2′′′′′ ) 3.6
Hz, H-1′′′′′), 6.92-7.43 (m, 80H, aromatic); 13C NMR (150 MHz,
CDCl3): δ 16.4, 29.5, 29.9, 48.5, 54.7, 66.6, 67.1, 68.2, 68.8, 69.0,
69.2, 69.3, 70.0, 72.3, 72.68, 72.74, 73.0, 73.3, 73.67, 73.69, 73.75,
73.80, 73.96, 74.75, 74.99, 75.12, 75.2, 75.4, 75.8, 76.2, 76.3, 76.6,
78.4, 79.3, 79.9, 80.6, 81.4, 81.8, 82.6, 83.2, 83.7, 96.0, 97.4, 101.6,
101.9, 102.8, 103.1, 103.7, 126.8, 126.92, 126.96, 127.1, 127.2,
127.36, 127.40, 127.45, 127.48, 127.51, 127.53, 127.67, 127.69,
127.73, 127.76, 127.83, 127.87, 127.90, 127.93, 128.01, 128.07,
128.10, 128.16, 128.27, 128.28, 128.34, 128.35, 128.38, 128.44,
128.50, 128.52, 128.53, 128.60, 128.64, 128.67, 128.71, 129.2,
138.1, 138.2, 138.3, 138.43, 138.47, 138.51, 138.57, 138.86, 138.88,
138.97, 139.06, 139.24, 139.51, 139.8, 140.0, 154.1; HRMS: [M
+ Na]+ C154H163Cl3N4NaO31 calcd 2692.0265, obsd 2692.0254.
1JC1′′′′′,H1′′′′′ ) 170.9 Hz, other five 1JC1,H1 ) 162.0 Hz, 162.0, 162.0,
162.0, 159.4 Hz.
3-Azidopropyl 2,3,4-Tri-O-benzyl-R-L-fucopyranosyl-(1 f 2)-
3,4,6-tri-O-benzyl-â-D-galactopyranosyl-(1 f 3)-4,6-benzylidene-
2-(2,2,2-tri-chloroethoxycarbonylamino)-2-deoxy-â-D-galacto-
pyranosyl-(1 f 3)-2,4,6-tri-O-benzyl-R-D-galactopyranosyl-(1 f
4)-2,3,6-tri-O-benzyl-â-D-galactopyranosyl-(1 f 4)-2,3,6-tri-O-
benzyl-â-D-glucopyranoside (20R) and 3-Azidopropyl 2,3,4-Tri-
O-benzyl-R-L-fucopyranosyl-(1 f 2)-3,4,6-tri-O-benzyl-â-D-
galactopyranosyl-(1 f 3)-4,6-benzylidene-2-(2,2,2-tri-chloro-
ethoxycarbonylamino)-2-deoxy-â-D-galactopyranosyl-(1 f 3)-
2,4,6-tri-O-benzyl-â-D-galactopyranosyl-(1 f 4)-2,3,6-tri-O-ben-
zyl-â-D-galactopyranosyl-(1 f 4)-2,3,6-tri-O-benzyl-â-D-glu-
copyranoside (20â). After the donor 18 (50 mg, 92.47 µmol) and
freshly activated molecular sieve MS-4 Å (500 mg) were stirred
for 30 min at room temperature in Et2O (4 mL), the solution was
cooled to -78 °C, followed by the addition of AgOTf (72 mg,
277.4 µmol) in Et2O (1.5 mL). The mixture was stirred for 5 min
at -78 °C, and then p-TolSCl (14.7 µL, 92.47 µmol) was added
into the solution (see the General Procedure for Single Step
Preactivation Based Glycosylation for precautions) The mixture was
vigorously stirred for 5 min, followed by the addition of a solution
of acceptor 13 (77.1 mg, 78.60 µmol) and TTBP (23 mg, 92.47
µmol) in CH2Cl2 (1 mL). The reaction mixture was stirred for 2 h
from -78 to -20 °C, and then the mixture was cooled down to
-78 °C, followed by the addition of AgOTf (24 mg, 92.47 µmol)
in Et2O (1 mL). The mixture was stirred for 10 min at -78 °C,
and then p-TolSCl (12.5 µL, 78.60 µmol) was added into the
solution. After stirring for 5 min, a solution of acceptor 19 (30.9
mg, 55.48 µmol) and TTBP (23 mg, 92.47 µmol) in CH2Cl2 (1
mL) was added slowly along the flask wall into the mixture, and
the reaction mixture was stirred for 2 h from -78 to -20 °C. The
mixture was cooled down again to -78 °C, followed by sequential
additions of AgOTf (24 mg, 92.47 µmol) in Et2O (1 mL), the last
acceptor 15 (35.7 mg, 36.99 µmol), and TTBP (23 mg, 92.47 µmol)
Three component one-pot synthesis procedure: after the donor
18 (50 mg, 92.47 µmol) and activated molecular sieve MS-4 Å
(500 mg) were stirred for 30 min at room temperature in Et2O (6
mL), the solution was cooled to -78 °C, followed by the addition
of AgOTf (72 mg, 277.4 µmol) in Et2O (1.5 mL). The mixture
was stirred for 5 min at -78 °C, and then p-TolSCl (14.7 µL, 92.47
µmol) was added into the solution (see the General Procedure for
Single Step Preactivation Based Glycosylation for precautions). The
mixture was vigorously stirred for 10 min, followed by addition of
a solution of acceptor 13 (81.7 mg, 83.22 µmol) and TTBP (23
mg, 92.47 µmol) in CH2Cl2 (1 mL). The reaction mixture was stirred
for 2 h from -78 to -20 °C, and then the mixture was cooled
down to -78 °C, followed by sequential additions of AgOTf (24
mg, 92.47 µmol) in Et2O (1 mL), acceptor 17 (90.5 mg, 64.73
µmol), and TTBP (23 mg, 92.47 µmol) in CH2Cl2 (1 mL). The
mixture was stirred for 5 min at -78 °C, and then p-TolSCl (13.2
J. Org. Chem, Vol. 72, No. 17, 2007 6419

Wang et al.
µL, 83.22 µmol) was added into the solution. The reaction mixture
was stirred for 3 h from -78 to 10 °C and then was quenched with
Et3N (40 µL) and concentrated under vacuum to dryness. The
resulting residue was diluted with CH2Cl2 (30 mL), followed by
filtration. The organic phase was washed with saturated aqueous
NaHCO3 and H2O and then dried over Na2SO4, filtered, and
concentrated. Silica gel column chromatography (2:1 hexanes-/
EtOAc) afforded 20R as a colorless gel (128 mg, 74%).
mixture of the obtained solid and Pd(OH)2 in MeOH/H2O/HOAc
(3 mL/1 mL/1 mL) was stirred under H2 at room temperature
overnight and then filtered. The filtrate was concentrated to dryness
under vacuum and then was coevaporated with H2O (10 mL) 3
times to remove AcOH. The aqueous phase was further washed
with CH2Cl2 (5 mL × 3) and EtOAc (5 mL × 3), and then the
aqueous phase was dried under vacuum to afford 2 (acetate salt)
as a white solid (16.2 mg, 50% for three steps). [R]D +27.8 (c )
1.4, H2O); 1H NMR (600 MHz, D2O): δ 1.00 (d, 3H, J ) 6.6 Hz,
H-6′′′′′), 1.74 (s, 3H), 1.79 (m, 2H), 1.83 (s, 3H), 2.95 (t, 2H, J )
6.6 Hz), 3.12 (t, 1H, J ) 8.4 Hz), 3.36-3.89 (m, 32H), 4.02-4.03
(m, 2H), 4.18 (t, 1H, J ) 6.0 Hz), 4.29 (d, 2H, J ) 7.8 Hz), 4.32
(d, 1H, J ) 7.8 Hz), 4.40 (d, 1H, J ) 7.8 Hz), 4.69 (d, 1H, J ) 3.6
Hz), 5.02 (d, 1H, J ) 3.6 Hz); 13C NMR (150 MHz, D2O): δ 15.4,
22.3, 23.4, 26.8, 37.7, 51.8, 60.1, 60.5, 61.1, 66.9, 67.9, 68.1, 68.6,
69.2, 69.3, 69.6, 70.2, 71.0, 72.0, 72.2, 73.0, 73.7, 74.5, 74.7, 75.0,
75.2, 75.6, 76.2, 76.4, 77.3, 78.3, 78.8, 99.4, 100.6, 102.2 (×2),
103.5, 104.1, 174.4; HRMS: [M + Na]+ C41H72N2NaO30 calcd
3-Azidopropyl R-L-Fucopyranosyl-(1 f 2)-â-D-galactopyra-
nosyl-(1 f 3)-2-acetamido-2-deoxy-â-D-galactopyranosyl-(1 f
3)-R-D-galactopyranosyl-(1 f 4)-â-D-galactopyranosyl-(1 f 4)-
â-D-glucopyranoside (2). The mixture of 20R (0.075 g, 0.028
mmol), 1 M NaOH (0.56 mL, 0.56 mmol), and THF (4 mL) was
stirred at 50 °C overnight and then concentrated to dryness. The
resulting residue was diluted with CH2Cl2 (50 mL), and the organic
phase was washed by H2O and then dried over Na2SO4, filtered,
and concentrated to dryness. The resulting residue was dissolved
in pyridine (2 mL), and a catalytic amount of DMAP was added.
Acetic anhydride (0.5 mL, 5.3 mmol) was added dropwise, and
the mixture was stirred at room temperature under N2 for 4 h. The
reaction was quenched by adding a few drops of H2O and then
diluted with EtOAc (20 mL). The organic phase was washed with
a saturated aqueous solution of NaHCO3 and H2O, and then dried
over Na2SO4, filtered, and concentrated to dryness. Silica gel column
chromatography (2:1 hexanes-/EtOAc) afforded the N-acetylation
product as a white solid. The mixture of the N-acetylation product,
1 M of PMe3 in THF (56 µL, 0.056 mmol), 0.1 M NaOH (0.5 mL,
0.05 mmol), and THF (3 mL) was stirred at 60 °C under N2
overnight. The mixture was concentrated, and the resulting residue
was diluted with CH2Cl2 (50 mL). The organic phase was washed
with H2O and then dried over Na2SO4, filtered, and concentrated
to dryness. The resulting residue was purified by quickly passing
through a short silica gel column (10:1, CH2Cl2-/MeOH). The
1
1
1095.4068, obsd 1095.4048. JC1′′′′′,H1′′′′′ ) 170.0 Hz, JC1′′,H1′′
)
1
171.2 Hz, other four JC1,H1 ) 162.6, 163.9, 162.4, 162.4 Hz.
Acknowledgment. We are grateful for financial support from
the University of Toledo, the National Institutes of Health (R01-
GM-72667), and the Pardee foundation. We dedicate this work
to Prof. Nina Berova, Columbia University, for her guidance
and continual encouragement over the years.
Supporting Information Available: Selected 1H, 13C, and 2-D
NMR spectra. This material is available free of charge via the
Internet at http://pubs.acs.org.
JO070585G
6420 J. Org. Chem., Vol. 72, No. 17, 2007