Glycosylation under thermodynamic control: Synthesis of the Di- and the hexasaccharide fragments of the O-SP of Vibrio Cholerae O:1 serotype ogawa from fully functionalized building blocks

Article abstract of DOI:10.1002/ejoc.200600851

The known 5-(methoxycarbonyl)pentyl α-glycoside of the hexasaccharide of the O-SP of Vibrio cholerae O:1, serotype Ogawa 31 was newly prepared from side-chain-equipped disaccharide building blocks. The intermediate tetrasaccharide 25 was prepared from the

Full text of DOI:10.1002/ejoc.200600851

FULL PAPER
DOI: 10.1002/ejoc.200600851
Glycosylation under Thermodynamic Control: Synthesis of the Di- and the
Hexasaccharide Fragments of the O-SP of Vibrio Cholerae O:1 Serotype
Ogawa from Fully Functionalized Building Blocks
[a]
[a]
ˇ
Roberto Adamo and Pavol Kovác*
Keywords: Carbohydrates / Oligosaccharides / Synthetic methods / Thioglycosides / Cholera vaccine
The known 5-(methoxycarbonyl)pentyl α-glycoside of the
hexasaccharide of the O-SP of Vibrio cholerae O:1, serotype
Ogawa 31 was newly prepared from side-chain-equipped di-
saccharide building blocks. The intermediate tetrasaccharide
25 was prepared from the disaccharide glycosyl acceptor 11
and the (1Ǟ2)-linked disaccharide thioglycoside glycosyl do-
nor 8, having a (non-participating) saccharide moiety at C-2
in the downstream end. When performed conventionally (at
room or at sub 0 °C temperatures), glycosylations with 11,
carried out without anchimeric assistance, showed poor ster-
eoselectivity but the formation of the 1,2-trans-glycosidic
linkage could be markedly improved through thermo-
dynamic control. This synthetic strategy towards 31 was
more efficient than the step-wise approach, which was based
on iterative glycosylation of 11 with 5 followed by delevuli-
noylation. Thermodynamic control improved considerably
the yields of glycosylation of tetrasaccharide glycosyl ac-
ceptor 26 with disaccharide donor 18, to give the fully pro-
tected hexasaccharide 28, and also a similar reaction of the
thioglycoside 18 with methyl 5-hydroxyhexanoate, to afford
the linker-equipped disaccharide 19. Sequential deacety-
lation and debenzylation of the hexasaccharide 28, and de-
protection of one of its intermediates, 19, gave the target
hexasaccharide 31, and the wanted disaccharide 22, respec-
tively.
(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim,
Germany, 2007)
gosaccharides. The latter synthetic strategy requires a set of
selectively removable protecting groups in intermediates. To
improve on our previous strategy[11] we have recently re-
ported[12] preparation of the 1-thio-α-perosaminide 5. It has
the 4-amino group functionalized with 2,4-di-O-acetyl-3-
deoxy--glycero-tetronic acid,[13] and is a potentially useful
synthon in the preparation of higher oligosaccharides in the
Vibrio cholerae O:1 series. The stable benzyl group at posi-
tion 3 in 5 eliminates problems of acyl group migration we
experienced[11] during glycosylations when the acetyl group
was at that position. The levulinoyl group at position 2 can
be selectively removed in the presence of acetyl groups in
the N-side-chain, and is capable of anchimeric assistance in
the glycosylation reactions.[12,14,15]
Utility of neoglycoconjugates from 5-(methoxycarbonyl)-
pentyl α-glycosides of di- and hexasaccharide fragments (22
and 31, respectively) of the O-SP of Vibrio cholerae O:1,
serotype Ogawa, as experimental vaccines has already been
proven.[16,17] Within our efforts to develop a clinically useful
vaccine for cholera, we explore, among other things, pos-
sibilities to improve existing synthetic strategies towards the
foregoing oligosaccharides. Here we describe a new syn-
thetic approach towards antigens 22 and 31 from fully func-
tionalized building blocks. We also compare the block-wise
and the step-wise assembly of the key tetrasaccharide inter-
mediate 25, using the side chain-equipped monosaccharide
5 and disaccharide 8 as glycosyl donors.
Introduction
Cholera is a very serious enteric disease caused by the
bacterium Vibrio cholerae. Intestinal infection is usually fol-
lowed by severe diarrhea with dehydration, rapid loss of
bodily fluids and electrolytes, which can quickly lead to de-
ath. More than 200 serogroups of V. cholerae have been
identified[1] differing in the structure of their O-specific
polysaccharide (O-PS). Until 1992, when a new serogroup
O:139 caused a cholera epidemic in the Indian subconti-
nent, the O:1 strain was thought to be the only Vibrio cho-
lerae bacterium pathogenic in humans.[2] Vibrio cholerae
O:1 occurs as two serotypes, Ogawa and Inaba, whose O-
PS are linear homopolymers of α-(1Ǟ2)-linked 3-deoxy--
glycero-tetronamido--perosamine.[3] The upstream perosa-
mine unit is 2-O-methylated only in the Ogawa serotype.[4–6]
Oligosaccharides composed of N-acylated amino sugars
can be built up by two strategies. The most common one[7–9]
consists in constructing the oligosaccharide from azido
sugars, which are eventually transformed into their N-acyl-
amido counterparts. In the alternative approach,[10,11] the
oligosaccharide is constructed from intermediates having
the acylamido side chain already in place, thus minimizing
the number of chemical manipulations with the higher oli-
[a] NIDDK, LBC, Section on Carbohydrates, National Institutes
of Health,
Bethesda, MD 20892-0815, USA
988
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Glycosylation under Thermodynamic Control
FULL PAPER
group, with the crystalline chloride 7, given rise to readily
by treatment[23] of 5 with Cl2 in CCl4 (Scheme 1). The reac-
tion mixture contained mainly 8 but a number of by-prod-
ucts were also formed. The yield of 8 was much lower
(58%) than what would be expected from the outcome of a
similar conversions leading to the 2-O-acetyl derivative of
the diazido disaccharide 13 lacking the amido group.[19,24]
The thioglycoside 5 was one of the by-products (isolated in
10% yield), showing that the low yield of 8 was, at least
partially, due to the transfer of the strongly nucleophilic
ethanethio group from the thioglycoside acceptor 6 to the
chloride donor 7. Similar transformations have been ob-
served.[25–27]
Results and Discussion
Our previous syntheses[11,18–22] of higher oligosaccha-
rides in the Vibrio cholerae O:1 series had their shortcom-
ings due to either instability of protecting groups, lack of
stereoselectivity of glycosylation reactions, or separation
problems involved. Also, losses resulting from multiple
chemical manipulations with high oligosaccharides we ex-
perienced during some previous approaches suggested that,
rather than a stepwise approach, a suitable block wise strat-
egy using fully functionalized intermediates as building
blocks should be pursued. Therefore, in the present synthe-
sis of the Ogawa hexasaccharide 31 from side-chain-
equipped building blocks, we first prepared the disaccharide
Having alcohol 11 at hand, it appeared that methylation
glycosyl acceptor 11 by NIS/AgOTf-promoted glycosyla- at O-2 followed by deprotection would readily give one of
tion of 4 with the known[12] thioglycoside 5 to give 10, the target products, the disaccharide 22. However, all
followed by selective removal of the Lev ester group attempts to methylate the disaccharide 11 failed due to ace-
(Scheme 1).
tyl protecting groups which were labile in both basic or
The linker-equipped α-glycoside 3 was prepared in 88% acidic conditions. Unsuccessful conversions 11Ǟ19 (MeI/
yield from the known acetate 1[12] and methyl 6-hydroxy- AgO, MeOTf/Et3SiOTf, or CH2N2/BF3·Et2O; these reac-
hexanoate by BF3·Et2O-promoted glycosylation. Alterna- tions are not described in the Exp. Sect.) and low yield of
tively, glycosylation of methyl 6-hydroxyhexanoate with 5 the conversion 6 + 7Ǟ8 prompted us to prepare the disac-
was mediated with NIS/AgOTf. The latter reaction was less charide donors 8 and 18 from the known diazido disaccha-
stereoselective giving 3 in 70% yield, together with the β ride 13[19,24] (Scheme 2). Accordingly, after selective re-
anomer 2 (20%). After cleavage of the Lev group, the ob- duction[28] of 13 (Ǟ14), followed by amidation with 2,4-di-
tained 2-hydroxy sugar 4 was coupled with 5, to form the O-acetyl-3-deoxy--glycero-tetronic acid[13] (14Ǟ15), ester-
desired 1,2-trans-linked disaccharide with high stereoselecti- ification of 15 with levulinic acid in the presence of EDAC/
vity: the α (10) and β product (12) were obtained in 80 and 4-Dimethylaminopyridine provided the disaccharide thio-
6% yield, respectively.
glycoside 8 (82%) in three steps. A similar synthetic scheme
The disaccharide donor 8 was obtained by coupling of was applied to prepare the 2-O-methylated disaccharide 18.
the thioglycoside 6, prepared from 5 by cleavage of the Lev Methylation[29,30] of 13 (Ǟ16), followed by reduction[28] of
Scheme 1. a: HO(CH2)5COOMe, BF3·Et2O, CH2Cl2; b: HO(CH2)5COOMe, NIS, AgOTf, CH2Cl2; c: H2NNH2·AcOH/CH2Cl2, MeOH;
d: NIS, AgOTf, CH2Cl2; e: Cl2, CCl4; f: AgOTf, TMU, CH2Cl2.
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Scheme 2. a: H2S, Py/H2O, 40 °C; b: 2,4-di-O-acetyl-3-deoxy--glycero-tetronic acid, EDAC, CH2Cl2; c: LevOH, EDAC, 4-(dimeth-
ylamino)pyridine, CH2Cl2; d: MeI, KOH, Me2SO; e: HO(CH2)5COOMe, NIS, AgOTf, CH2Cl2; f: NaOMe, MeOH; g: H2, Pd/C, MeOH.
the azido groups with H2S afforded the diamino disaccha- ride 22, which was identical with the independently synthe-
ride 17, which was readily converted into the desired, crys- sized substance.[32] Using a higher-field instrument than
talline disaccharide donor 18.
Glycosidation of 18 with 5-(methoxycarbonyl)pentanol tra of the substance could now be fully assigned.
was carried out at various conditions to optimize the yield To evaluate efficiency of construction of oligosaccharides
during the original work,[32] resonances in the NMR spec-
of the linker-equipped disaccharide 19. Effect of various re- in this series by various approaches we have compared re-
action conditions are shown in Table 1. While the reaction sults of the stepwise and blockwise synthetic strategy
at room temperature and CH2Cl2 as solvent produced a towards tetrasaccharide 25. In the stepwise approach, the
mixture of anomers (α:β = 1:1, Entry 1), the amount of synthesis involved (Scheme 3) NIS/AgOTf-mediated coup-
the β anomer 20 slightly increased using CH3CN as solvent ling of the disaccharide acceptor 11 with donor with 5
(Entry 3) or when the reaction was conducted at –20 °C (Ǟ23, 76%), followed by delevulinoylation (Ǟ24, ca.
using CH2Cl2 as solvent (Entry 5). Addition of ether type 100%). Subsequent glycosylation of 24 with 5 gave 25
solvents to the reaction mixture, e.g. toluene/dioxane (1:4), (81%).
has been reported to have α-directional effect on glycosyl-
In the blockwise, NIS/AgOTf-mediated construction of
ation[31] but applying those conditions (Table, Entry 2) did the tetrasaccharide 25 from the disaccharide donor 8 and
not change the situation. Better α selectivity in the synthesis the acceptor 11, the reaction conducted at room tempera-
of 19 was achieved by thermodynamic control of the reac- ture gave a mixture of α- and β-linked tetrasaccharides 25
tion, namely by conducting the reaction at higher tempera- and 27, respectively, in a ratio of 2:1 (Table 1, Entry 8; com-
ture (see Exp. Sect. and Table 1, Entry 6 and 7). The bined yield 80%). Very similar, closely related 4-azido-oli-
amount of the thermodynamically more stable α anomer gosaccharides made by blockwise assembly from intermedi-
almost doubled when the reaction was performed at reflux ates lacking the acylamido group, were obtained with much
temperature (see Exp. Sect. and Table 1) and the com- better α stereoselectivity.[22,24,33] Attempts to improve the
pounds 19 and 20 were formed in a ratio of 1.8:1. Two-step yield of 25 by changing the glycosyl donor and promoter
deprotection of the α-glycoside 19 gave the target disaccha- were unsuccessful (Table 1, Entry 9). The latter two obser-
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Glycosylation under Thermodynamic Control
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Table 1. Effect of solvent and temperature on stereoselectivity of glycosylation.[a]
Entry Acceptor
Donor
Solvent
Procedure
Temperature[b] [°C]
Products
α:β
1
2
3
4
5
6
7
8
MeOCO(CH2)5OH
MeOCO(CH2)5OH
MeOCO(CH2)5OH
MeOCO(CH2)5OH
MeOCO(CH2)5OH
MeOCO(CH2)5OH
MeOCO(CH2)5OH
11
11
11
26
26
18
18
18
18
18
18
18
8
DCM
1:4 toluene/1,4-dioxane
MeCN
A
A
A
A
A
B
B
A
room temp.
room temp.
room temp.
room temp.
–20
60
(reflux)
room temp.
room temp.
(reflux)
room temp.
(reflux)
19, 20
19, 20
19, 20
19, 20
19, 20
19, 20
19, 20
25, 27
25, 27
25, 27
28, 29
28, 29
1:1
1:1
1:1.1
1:1
1:1.5
1.2:1
1.8:1
2:1
2:1
5:1
3:1
5:1
4:1 toluene/DCM
DCM
ca. 7:1 toluene/DCM[c]
ca. 7:1 toluene/DCM[c]
DCM
9
9
DCM
see Exp. Sect.
10
11
12
8
18
18
ca. 7:1 toluene/DCM[c]
DCM
B
A
B
ca. 7:1 toluene/DCM[c]
[a] Determined by 1H NMR spectroscopy. [b] Reaction time, 15–30 min. [c] The reaction was performed in a well-ventilated hood.
Carbohydrate synthons were dissolved in a little DCM to aid solubilization, and toluene was added followed by molecular sieves. The
mixture, kept in a septum-closed flask under inert gas, was then brought to reflux while DCM was allowed to escape through a needle.
The rest of reagents was added when DCM largely escaped, the reagent flask was equipped with a reflux condenser, and the mixture was
kept under reflux until TLC showed that the reaction was complete.
Scheme 3. a: NIS, AgOTf, CH2Cl2; b: H2NNH2·AcOH, CH2Cl2/MeOH; c: 5, NIS, AgOTf, CH2Cl2; d: AgOTf, 2,6-di-tert-butyl-4-methyl-
pyridine, CH2Cl2.
vations strongly suggest that the lower α stereoselectivity in get compound are comparable, the blockwise approach re-
our situation was due to the presence of the N-side chain quires fewer difficult purifications by chromatography (see
in the building blocks involved. Nevertheless, the yield of Exp. Sect.).
25 could be improved, as was the case of making the glyco-
To prepare the hexasaccharide 28, the tetrasaccharide 25
side 19, by performing the glycosylation reaction at reflux was selectively deprotected at the 2IV and compound 26
temperature: compounds 25 and 27 were formed in a com- thus formed was used for glycosylation with the 2II-O-meth-
bined yield of 93% (α:β = 5:1, Table 1, Entry 10). Thermo- ylated disaccharide donor 18. When thermodynamic con-
dynamic control, even in absence of anchimeric assistance, trol of the reaction was applied, the ratio of products
and with a more hindered nucleophile than methyl 6-hy- formed (28 and 29) was increased from 3:1 (Table 1, Entry
droxyhexanoate, resulted in more favored formation of the 11) to 5:1 (Table 1, Entry 12). Sequential deprotection (de-
thermodynamically more stable α product. Overall, we con- acetylation, Ǟ30) followed by debenzylation gave the tar-
sider the blockwise approach to compound 25 superior to get, deprotected hexasaccharide 31, which was identical
the stepwise preparation. While the overall yields of the tar- with the previously synthesized substance.[18] More detailed
Eur. J. Org. Chem. 2007, 988–1000
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R. Adamo, P. Kovácˇ
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Scheme 4. a: 18, NIS, AgOTf, CH2Cl2; b: NaOMe, MeOH; c: H2, Pd/C, MeOH.
a prime and those with the spacer (linker) are denoted with a
double prime. When reporting assignments of NMR signals, sugar
residues in oligosaccharides are serially numbered, beginning with
the one bearing the aglycon, and are identified by a Roman nu-
meral superscript in listings of signal assignments. Liquid
Chromatography–Electron Spray-Ionization Mass Spectrometry
(ESI-MS) was performed with a Hewlett–Packard 1100 MSD spec-
trometer. Gas chromatography Electron Impact Mass Spectrome-
try (GC-EI-MS) was performed with a Hewlett–Packard 5898A
spectrometer. Attempts have been made to obtain correct combus-
assignment of NMR resonances in spectra of 31 could now
be made, using the 600 MHz spectrometer (Scheme 4).
In conclusion, the known compounds 31 and 22 were
newly synthesized from side-chain-equipped, fully function-
alized building blocks. The poor stereoselectivity of glyco-
sylations, compared with similar reactions involving 4-azido
intermediates which lack the acylamido group at the same
position,[18,22,24,33] could not be improved by the solvent ef-
fect or by changing nature of the glycosyl donor. However,
glycosylations with the same reactants could be made more tion analysis data for all new compounds. However, some com-
pounds tenaciously retained traces of solvents, despite exhaustive
drying, and analytical figures for carbon could not be obtained
within Ϯ0.4%. Structures of these compounds follow unequivo-
cally from the mode of synthesis, NMR spectroscopic data and m/z
values found in their mass spectra, and their purity was verified by
TLC and NMR spectroscopy. To obtain dry silica gel, the commer-
cial material was dried at 160 °C overnight. 5% Palladium-on-char-
coal catalyst (Escat 103) was purchased from Engelhard Industries.
1-(3-Dimethylaminopropyl)-3-ethyl-carbodiimide (EDAC) was
purchased from ACROS Organics. N-Iodosuccinimide (NIS) was
freshly crystallized from CCl4/dioxane. Silver trifluoromethanesul-
fonate (AgOTf) was purchased from Aldrich Chemical Co, and
dried at 100 °C for 2 h before use. Rubber septa used to close reac-
tion flasks containing organic solvents were protected with a thin
Teflon sheet, to avoid leaching. Solutions in organic solvents were
dried with anhydrous Na2SO4, and concentrated at 40 °C/2 kPa.
α-selective when they were conducted under thermo-
dynamic control, showing that with the complex synthons
involved, temperature is the key parameter to control the
formation of the thermodynamically more stable α-product.
Experimental Section
General Methods: Unless stated otherwise, optical rotations were
measured at ambient temperature with a Perkin–Elmer automatic
polarimeter, Model 341. All reactions were monitored by thin-layer
chromatography (TLC) on silica gel 60 coated glass slides. Column
chromatography was performed by elution from columns of silica
gel with the CombiFlash Companion Chromatograph (Isco, Inc.).
Solvent mixtures less polar than those used for TLC were used at
the onset of separation. Nuclear Magnetic Resonance (NMR) spec-
tra were measured at 300 MHz (1H) and 75 MHz (13C) with a Var-
ian Gemini or Varian Mercury spectrometer, or at 600 MHz (1H)
and 150 MHz (13C) with a Bruker Avance 600 spectrometer. As-
signments of NMR signals were made by homonuclear and hetero-
nuclear 2-dimensional correlation spectroscopy, run with the soft-
ware supplied with the spectrometers. Assignment of 13C NMR
spectra of some higher oligosaccharides was aided by comparison
with spectra of related substances reported previously from this
laboratory or elsewhere.[33] When the latter approach was used, to
aid in the 13C NMR signal-nuclei assignments, advantage was
taken of variations of line intensity expected for oligosaccharides
belonging to the same homologous series.[34,35] Thus, spectra
showed close similarity of chemical shifts of equivalent carbon
atoms of the internal residues, and an increase in the relative inten-
sity of these signals with the increasing number of -perosamine
residues in the molecule. When reporting assignment of NMR sig-
nals, nuclei associated with the 4-amido side chain are denoted with
General Procedure for Removal of the 2-O-Levulinoyl Group: Hydra-
zine acetate (1.2 mmol) in MeOH (2 mL) was added to a mixture
of 2-O-levulinoyl sugar (1 mmol) in CH2Cl2 (20 mL), and the mix-
ture was stirred overnight at room temperature, when TLC showed
that the reaction was complete. The mixture was concentrated, and
the product was isolated by chromatography.
General Procedure for Glycosylation with NIS/AgOTf
Procedure A: Molecular sieves (4 Å, 0.5 g) were added to a stirred
solution of the glycosyl acceptor (1 mmol) and thioglycoside glyco-
syl donor (1.2–1.3 mmol) in CH2Cl2 (10–15 mL). After 15–30 min,
NIS (1.5 mmol) followed by solid AgOTf (0.5 mmol) was added.
The mixture, which became red almost instantaneously, was stirred
at room temperature (unless specified otherwise in Table 1) for 15–
30 min, when TLC showed that the reaction was complete. After
filtration through a celite pad into a separating funnel and par-
titioning of the filtrate between CH2Cl2 and aq Na2S2O3/aq
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Glycosylation under Thermodynamic Control
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NaHCO3, the combined organic layers were dried, concentrated,
and the residue was chromatographed.
54.38 (C-4), 51.25 (OCH3), 37.99 (CH2CO), 33.79 (C-5ЈЈ), 30.84 (C-
3Ј), 29.70 (CH3), 28.93 (CH2COO), 28.05 (C-2ЈЈ), 25.33 (C-3ЈЈ),
24.50 (C-4ЈЈ), 20.63, 20.59 (2CH3CO), 17.87 (C-6) ppm. ESI-MS:
m/z: 688.2947 ([M + Na]+; calcd. 688.2922).
Procedure B: Molecular sieves (4 Å, 0.5 g) were added to a stirred
solution of the glycosyl acceptor (1 mmol) and the thioglycoside
glycosyl donor (1.2–1.3 mmol) in ca. 7:1 toluene/CH2Cl2 (ca.
15 mL) under nitrogen (Table 1, footnote [c]). The mixture was
brought to reflux, unless specified otherwise in Table 1, and a solid
mixture of NIS (1.5 mmol) and AgOTf (0.5 mmol) was quickly
added. The stirring was continued at the same temperature until
TLC showed that the reaction was complete (~15–30 min). After
cooling to room temperature, the product was isolated as described
above.
5-(Methoxycarbonyl)pentyl 3-O-Benzyl-4-(2,4-di-O-acetyl-3-deoxy-
L
-glycero-tetronamido)-4,6-dideoxy-α-D-mannopyranoside (4): Fol-
lowing the general procedure for cleavage of Lev group and
chromatography (4:1Ǟ3:2 hexane/acetone) afforded the amorph-
1
ous compound 4 (555 mg, 98%). [α]D = +7 (c = 0.4; CHCl3). H
NMR (600 MHz, CDCl3): δ = 6.24 (d, JNH,4 = 9.2 Hz, 1 H, NH),
5.16 (dd, J2Ј,3Јa = 8.3, J2Ј,3Јb = 4.6 Hz, 1 H, 2Ј-H), 4.83 (d, J1,2
=
1.7 Hz, 1 H, 1-H), 4.67, 4.51 (2d, 2J = 11.8 Hz, 2 H, CH2Ph), 4.18–
4.14 (m, 1 H, 4Јa-H), 4.10–4.06 (m, 1 H, 4Јb-H), 4.03–3.98 (m, 4-
5-(Methoxycarbonyl)pentyl 3-O-Benzyl-4-(2,4-di-O-acetyl-3-deoxy-
H, J = 10.1 Hz, 2 H, 2-H, incl. 4.01, q), 3.82–3.76 (m, 3-H, J2,3
=
L
-glycero-tetronamido)-4,6-dideoxy-2-O-levulinoyl-α-D-manno-
3.2, J3,4 = 10.3 Hz, 2 H, 5-H, incl. dd, 3.78), 3.70–3.65 (m, 4 H,
1aЈЈ-H, incl. 3.67, s, OCH3), 3.41, 3.39 (2t, J = 6.0 Hz, 1 H, 1bЈЈ-
H), 2.72 (br. s, 1 H, 2-OH), 2.33 (t, J = 7.3 Hz, 5ЈЈ-H), 2.22–2.17
(m, 1 H, 3Јa-H), 2.09–2.03 (m, 7 H, 3Јb-H, incl. 2s, 2.06, 2.03,
2CH3CO), 1.68–1.57 (m, 4 H, 2ЈЈ-H, 4ЈЈ-H), 1.43–1.35 (m, 2 H, H-
3ЈЈ), 1.20 (d, J5,6 = 6.3 Hz, 3 H, 6-H) ppm. 13C NMR (150 MHz,
CDCl3): δ = 174.31 (COOCH3), 170.82 (NHCO), 169.73, 169.38
(2CH3CO), 98.96 (C-1), 76.08 (C-3), 71.09 (C-2Ј), 71.00 (CH2Ph),
67.09 (C-1ЈЈ), 66.95 (C-2), 66.86 (C-5), 59.99 (C-4Ј), 52.00 (C-4),
51.48 (OCH3), 33.87 (C-5ЈЈ), 30.84 (C-3Ј), 28.72 (C-2ЈЈ), 25.62 (C-
3ЈЈ), 24.43 (C-4ЈЈ), 20.77, 20.67 (2CH3CO), 17.80 (C-6) ppm. ESI-
MS: m/z: 590.2577 ([M + Na]+; calcd. 590.2601). C28H41NO11
(567.6): calcd. C 59.25, H 7.28, N 2.47; found C 59.09, H 7.44, N
2.74.
pyranoside (3). From Acetate 1: Activated molecular sieves (1.25 g)
were added to a stirred solution of 1-O-acetyl derivative 1[12]
(2.18 g, 3.76 mmol) and methyl 6-hydroxyhexanoate[36] (2.75 g,
18.80 mmol). After 30 min, BF3·Et2O (2.38 mL, 18.8 mmol) was
added and the stirring was continued overnight, when TLC (2:1
hexane/acetone) showed that the reaction was complete and that
one product was formed. The mixture was filtered, the filtrate was
washed with iced aq. NaHCO3, and the combined organic layers
were concentrated. Chromatography of the residue (9:1Ǟ2:1 hex-
ane/acetone) gave the linker-equipped mannoside 3 (2.20 g, 88%).
From Thioglycoside 5: Following procedure A for glycosylation,
methyl 6-hydroxyhexanoate (TLC 2:1 hexane/acetone), afforded af-
ter chromatography products 3 and 2.
Compound 3: (466 mg, 70 %). [α]D = +29 (c = 0.8; CHCl3). 1H
NMR (600 MHz, CDCl3): δ = 6.09 (d, JNH,4 = 9.1 Hz, 1 H, NH),
5.34 (dd, J1,2 = 1.9, J2,3 = 3.2 Hz, 1 H, 2-H), 5.17 (dd, J2Ј,3Јa = 8.3,
Ethyl 3-O-Benzyl-4-(2,4-di-O-acetyl-3-deoxy-
L
-glycero-tetron-
amido)-4,6-dideoxy-1-thio-α-
D
-mannopyranoside (6): Compound
5[12] was treated as described in the general procedure for removal
of Lev group. Chromatography of the crude product with 2:1 hex-
ane/acetone afforded pure 6 (445 mg, 92%); m.p. 88–89 °C (from
EtOAc/iPr2O). [α]20 = +85.3 (c = 0.5; CHCl3). 1H NMR (600 MHz,
2
J2Ј,3Јb = 4.6 Hz, 1 H, 2Ј-H), 4.75 (d, 1 H, 1-H), 4.64, 4.35 (2d, J
= 11.7 Hz, 2 H, CH2Ph), 4.17–4.13 (m, 1 H, 4Јa-H), 4.08–4.04 (m,
1 H, 4Јb-H), 3.97 (q, J = 10.4 Hz, 1 H, 4-H), 3.83 (dd, J3,4
=
10.6 Hz, 1 H, 3-H), 3.81–3.76 (m, 1 H, 5-H), 3.67–3.63 (m, 4 H,
1a"-H, incl. s, 3.66, OCH3), 3.40, 3.39 (2t, J = 6.0 Hz, 1 H, 1b"-
H), 2.74–2.62 (m, 4 H, CH2CH2), 2.33 (t, J = 7.5 Hz, 2 H, 5ЈЈ-H),
2.21–2.03 (m, 11 H, 3Јa,b-H, incl. 3s, 2.17, 2.04, 2.03, 2CH3CO,
CH3), 1.69–1.56 (m, 4 H, 2ЈЈ-H, 4ЈЈ-H), 1.44–1.35 (m, 2 H, 3ЈЈ-H),
1.21 (d, J5,6 = 6.3 Hz, 3 H, 6-H) ppm. 13C NMR (150 MHz,
CDCl3): δ = 206.29 (CH2CO), 174.29 (COOCH3), 171.94
(CH2COO), 170.77 (NHCO), 169.60, 169.34 (2CH3CO), 97.46
(JC,H = 169.5 Hz, C-1), 73.65 (C-3), 71.05 (C-2Ј), 70.57 (CH2Ph),
67.42 (C-2), 67.38 (C-5), 67.26 (C-1ЈЈ), 59.91 (C-4Ј), 52.47 (C-4),
51.47 (OCH3), 37.91 (CH2CO), 33.83 (C-5ЈЈ), 30.86 (C-3Ј), 29.69
(CH3), 28.66 (CH2COO), 28.10 (C-2ЈЈ), 25.59 (C-3ЈЈ), 24.39 (C-4ЈЈ),
20.76, 20.68 (2CH3CO), 17.90 (C-6) ppm. ESI-MS: m/z: 688.2945
([M + Na]+; calcd. 688.2922). C28H39NO10S (665.3): calcd. C 59.54,
H 7.12, N 2.10; found C 59.43, H 7.28, N 2.07.
CDCl3): δ = 5.89 (d, JNH,4 = 9.1 Hz, 1 H, NH), 5.34 (d, J1,2
=
1.4 Hz, 1 H, 1-H), 5.17 (dd, J2Ј,3Јa = 8.1, J2Ј,3Јb = 4.7 Hz, 1 H, 2Ј-
H), 4.65, 4.49 (2 d, 2J = 11.8 Hz, 2 H, CH2Ph), 4.19–4.15 (m, 1 H,
4Јa-H), 4.13–4.06 (m, 3 H, H-5, H-2, 4Јb-H), 4.01 (q, J = 9.7 Hz,
1 H, H-4), 3.73 (dd, J2,3 = 3.2, J3,4 = 10.3 Hz, 1 H, 3-H), 2.75 (br.
s, 1 H, 2-OH), 2.69–2.55 (m, 2 H, SCH2CH3), 2.24–2.17 (m, 1 H,
3Јa-H), 2.09–2.04 (m, 7 H, 3Јb-H, incl. 2s, 2.07, 2.05, 2CH3CO),
1.29 (t, J = 7.4 Hz, 3 H, SCH2CH3), 1.21 (d, J5,6 = 6.2 Hz, 3 H, 6-
H) ppm. 13C NMR (150 MHz, CDCl3): δ = 170.94 (NHCO),
169.73, 169.41 (2 CH3CO), 83.08 (C-1), 76.10 (C-3), 71.13 (C-2Ј),
71.05 (CH2Ph), 68.31 (C-2), 67.58 (C-5), 59.97 (C-4Ј), 52.37 (C-4),
30.89 (C-3Ј), 25.04 (SCH2CH3), 20.86, 20.81 (2 CH3CO), 17.76 (C-
6), 14.83 (SCH2CH3) ppm. ESI MS: m/z: 506.1825 ([M + Na]+;
calcd. 506.1834). C23H33NO8S (483.2): calcd. C 57.13, H 6.88, N
2.90; found C 56.85, H 6.86, N 2.87.
Compound 2: (133 mg, 20%). 1H NMR (600 MHz, CDCl3): δ =
6.15 (d, JNH,4 = 7.5 Hz, 1 H, NH), 5.60 (d, J2,3 = 2.8 Hz, 1 H, 2-
3-O-Benzyl-4-(2,4-di-O-acetyl-3-deoxy-L-glycero-tetronamido)-4,6-
H), 5.13 (dd, J2Ј,3Јa = 7.7, J2Ј,3Јb = 4.6 Hz, 1 H, 2Ј-H), 4.66, 4.30 dideoxy-2-O-levulinoyl-α-
(2d, J = 11.3 Hz, 2 H, CH2Ph), 4.52 (s, 1 H, 1-H), 4.21–4.04 (m, CCl4 (20 mL, 2 mmol) was added to a solution of thioglycoside 5
1 H, 4Јa,b-H), 3.92–3.82 (m, 3-H, J3,4 = 10.7 Hz, 3 H, 5-H, 1a"-H, (730 mg, 1.25 mmol) in CH2Cl2 (1 mL). The solution turned yellow
D
-mannopyranosyl Chloride (7): 0.1  Cl2/
2
incl. dd, 3.90), 3.67 (s, 3 H, OCH3), 3.54–3.39 (m, 4-H, J = 10.4 Hz,
2 H, 1b"-H, incl. q, 3.51), 2.80–2.66 (m, 4 H, CH2CH2), 2.34 (t, J
= 7.5 Hz, 2 H, 5ЈЈ-H), 2.21–2.04 (m, 11 H, 3Јa,b-H, incl. 3s, 2.14,
2.06, 2.04, 2CH3CO, CH3), 1.70–1.56 (m, 4 H, 2ЈЈ-H, 4ЈЈ-H), 1.44–
and TLC (9:1 toluene/acetone) showed that the starting material
had been consumed. The mixture was concentrated with co-evapo-
ration of toluene, and the residue was chromatographed on dry
silica gel to give the chloride 6 (625 mg, 89%); m.p. 104–105 °C
1.33 (m, 2 H, 3ЈЈ-H), 1.28 (d, J5,6 = 6.1 Hz, 3 H, 6-H) ppm. 13C (from iPr2O containing a few drops of EtOAc). [α]D = +26 (c = 0.6;
NMR (150 MHz, CDCl3): δ = 206.16 (CH2CO), 174.39 (CO-
OCH3), 172.15 (CH2COO), 170.80 (NHCO), 169.57, 169.45 H, 1-H), 5.94 (d, JNH,4 = 8.3 Hz, 1 H, NH), 5.48 (d, J2,3 = 2.8 Hz,
CHCl3). 1H NMR (300 MHz, CDCl3): δ = 6.02 (d, J1,2 = 1.8 Hz, 1
(2CH3CO), 98.52 (JC,H = 155 Hz, C-1), 74.48 (C-3), 70.91 (C-2Ј),
70.70 (CH2Ph), 69.96 (C-5), 69.32 (C-1ЈЈ), 67.36 (C-2), 59.82 (C-4Ј),
1 H, H-2), 5.17 (dd, J2Ј,3Јa = 8.0, J2Ј,3Јb = 4.9 Hz, 1 H, 2Ј-H), 4.63,
4.37 (2d, 2J = 12.0 Hz, 2 H, CH2Ph), 4.21–3.94 (m, 4-H, J3,4
=
Eur. J. Org. Chem. 2007, 988–1000
© 2007 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
993

R. Adamo, P. Kovácˇ
FULL PAPER
10.1 Hz, 3-H; q, 3.99, J = 10.4 Hz, 5 H, 4Јa,b-H, H-5, incl. dd,
4.02), 2.84–2.56 (m, 4 H, CH2CH2), 2.23–2.00 (m, 11 H, 3Јa,b-H,
incl. 3s, 2.17, 2.08, 2.03, 2CH3CO, CH3), 1.25 (d, J5,6 = 5.8 Hz, 3
3-O-Benzyl-4-(2,4-di-O-acetyl-3-deoxy-
dideoxy-2-O-levulinoyl-α-
(2,4-di-O-acetyl-3-deoxy-
L
-glycero-tetronamido)-4,6-
D
-mannopyranosyl-(1Ǟ2)-3-O-benzyl-4-
L
-glycero-tetronamido)-4,6-dideoxy-α-
D-
H, 6-H) ppm. 13C NMR (75 MHz, CDCl3): δ = 206.24 (CH2CO), mannopyranosyl Chloride (9): A solution of the thioglycoside 8
171.62 (CH2COO), 170.86 (NHCO), 169.58, 169.52 (2CH3CO),
90.14 (JC,H = 183.8 Hz, C-1), 71.65 (C-3), 70.98 (C-2Ј), 70.80 (0.1  Cl2/CCl4, 12 mL), as described above for a similar conver-
(CH2Ph), 70.57 (C-5), 69.40 (C-2), 59.83 (C-4Ј), 52.17 (C-4), 37.80 sion (TLC 1:4 hexane/EtOAc). Chromatography on a column of
(CH2CO), 30.80 (C-3Ј), 29.68 (CH3), 27.90 (CH2COO), 20.80, dry silica gel afforded chloride 9 (800 mg, 91%); m.p. 156–157 °C
20.74 (2CH3CO), 17.54 (C-6) ppm. ESI-MS: m/z: 578.1752 ([M + (from iPrO2 containing a few drops of EtOAc). [α]20 = –1.5 (c =
Na]+; calcd. 578.1769). C26H34ClNO10 (555.2): calcd. C 56.16, H 0.3; CHCl3). 1H NMR (300 MHz, CDCl3): δ = 6.18 (d, JNH,4
(980 mg, 0.98 mmol) in CH2Cl2 (2 mL) was treated with chlorine
=
6.16, N 2.52; found C 56.33, H 6.16, N 2.50.
8.3 Hz, 1 H, NH), 6.09 (2d, overlapped, 2 H, J4,NH = 8.9 Hz, NH;
J1,2 = 1.8 Hz, 1I-H), 5.42 (dd, J2,3 = 2.5 Hz, 1 H, 2II-H), 5.22–5.16
(m, 2 H, 2ϫ2Ј-H), 4.83 (d, 1 H, J1,2 = 1.8 Hz, 1II-H), 4.63–4.37
Ethyl 3-O-Benzyl-4-(2,4-di-O-acetyl-3-deoxy-L-glycero-tetronami-
do)-4,6-dideoxy-2-O-levulinoyl-α-
zyl-4-(2,4-di-O-acetyl-3-deoxy- -glycero-tetronamido)-4,6-dideoxy-
1-thio-α- -mannopyranoside (8)
D-mannopyranosyl-(1Ǟ2)-3-O-ben-
2
(4d, J = 11.7 Hz, 4 H, 2CH2Ph), 4.25–3.96 (m, 9 H, 2I-H, 3I-H,
L
2ϫ4Јa,b-H, 4I,II-H, 5I-H), 3.87–3.76 (m, 2 H, 5II-H, incl. dd, 3.84,
J3,4 = 10.5 Hz, 3II-H), 2.77–2.61 (m, 4 H, CH2CH2), 2.26–1.97 (m,
19 H, 2ϫ3Јa,b-H, incl. 5s, 2.17, 2.11, 2.09, 2.07, 2.04, 4CH3CO,
CH3), 1.22, (d, J5,6 = 5.5 Hz, 3 H, 6I-H), 1.18 (d, J5,6 = 6.2 Hz, 3
H, 6II-H) ppm. 13C NMR (75 MHz, CDCl3): δ = 206.43 (CH2CO),
171.70 (CH2COO), 170.96, 170.90 (2NHCO), 169.76, 169.70,
169.57, 169.60 (4 C, 4CH3CO), 99.61 (JC,H = 170.4 Hz, C-1II),
91.63 (JC,H = 182.0 Hz, C-1I), 77.30 (C-2I), 73.16 (C-3I), 72.74 (C-
3II), 71.60 (CH2Ph), 71.08, 71.00 (2ϫC-2Ј), 70.73 (C-5I), 70.49
(CH2Ph), 68.76 (C-5II), 67.04 (C-2II), 59.93, 59.86 (2ϫC-4Ј), 52.10,
51.88 (C-4I,II), 37.89 (CH2CO), 30.88, 30.80 (2 ϫ C-3Ј), 29.73
(CH3), 28.04 (CH2COO), 20.84, 20.81 (4 C, 4CH3CO), 17.85 (C-
6II), 17.61 (C-6I) ppm. ESI-MS: m/z: 999.3475 ([M + Na]+; calcd.
999.3506). C47H61ClN2O18 (976.4): calcd. C 57.75, H 6.29, N 2.87;
found C 57.50, H 6.31, N 2.91.
D
From Glycosyl Chloride 6 and Alcohol 7: A solution of the chloride
6 (130 mg, 0.23 mmol) was added dropwise to a mixture of the
acceptor 7 (110 mg, 0.21 mmol), AgOTf (59 mg, 0.23 mmol), TMU
(30 µL, 0.23 mmol) and molecular sieves (150 mg) in CH2Cl2
(3 mL) at –40 °C. The cooling was removed, and the mixture was
stirred at room temperature. When TLC (2:1 hexane/acetone)
showed the reaction to be complete (~2 h), the mixture was washed
successively with 10% HCl and aq NaHCO3, the combined organic
layers were dried, concentrated, and the residue was chromato-
graphed (9:1 Ǟ 8.5:1.5 toluene/acetone). First eluted was a com-
pound which co-chromtographed with 5 (11 mg, 10 %) whose
NMR spectroscopic data showed it to be identical with 5.
Next eluted was compound 8 (120 mg, 58 %); m.p. 179–180 °C
(from iPr2O containing a few drops of EtOAc). [α]20 = +2.5 (c =
5-(Methoxycarbonyl)pentyl 3-O-Benzyl-4-(2,4-di-O-acetyl-3-deoxy-
L
-glycero-tetronamido)-4,6-dideoxy-2-O-levulinoyl-α-
pyranosyl-(1Ǟ2)-3-O-benzyl-4-(2,4-di-O-acetyl-3-deoxy-
tetronamido)- 4,6-Dideoxy-α-
D
-manno-
-glycero-
0.6; CHCl3). 1H NMR (600 MHz, CDCl3): δ = 5.82 (d, JNH,4
=
L
8.8 Hz, 1 H, NHI), 5.80 (d, JNH,4 = 9.2 Hz, 1 H, NHII), 5.44 (dd,
J1,2 = 2.2, J2,3 = 3.1 Hz, 1 H, 2II-H), 5.26 (d, J1,2 = 1.6 Hz, 1 H,
1I-H), 5.19 (2dd, J2Ј,3Јa = 8.0, J2Ј,3Јb = 4.6 Hz, 2 H, 2ϫ2Ј-H), 4.83
(d, 1 H, 1II-H), 4.63, 4.39 (2d, 2J = 11.8 Hz, 2 H, CH2Ph), 4.59,
D
-mannopyranoside (10): Reaction of
4 (4.15 g, 7.31 mmol) and 5 (4.67 g, 8.04 mmol), according to pro-
cedure A for glycosylation (TLC 2:1 hexane/acetone) gave, after
chromatography (4:1 toluene/acetone) first syrupy disaccharide 10
2
4.47 (2d, J = 11.9 Hz, 2 H, CH2Ph), 4.21–4.13 (m, 2 H, 2ϫ4Јa-
1
(6.30 g, 80%). [α]20 = –23 (c = 0.8; CHCl3). H NMR (600 MHz,
H), 4.11–4.03 (m, 4 H, 2ϫ4Јb-H, 4II-H, 5I-H), 4.00 (m, partially
overlapped, 1 H, 2I-H), 3.98 (q, partially overlapped, J = 10.1 Hz,
4I-H), 3.84–3.79 (m, 3II-H, J3,4 = 10.6 Hz, 2 H, 5II-H, incl. dd,
3.81), 3.81 (dd, J2,3 = 2.9, J3,4 = 10.4 Hz, 1 H, 3I-H), 2.77–2.53 (m,
6 H, CH2CH2, SCH2CH3), 2.26–2.01 (m, 19 H, 2ϫ3Јa,b-H, incl.
5s, 2.16, 2.10, 2.09, 2.05, 2.03, 4CH3CO, CH3), 1.27 (t, J = 7.4 Hz,
CDCl3): δ = 6.16 (d, JNH,4 = 9.1 Hz, 1 H, NHI), 5.76 (d, JNH,4
=
9.2 Hz, 1 H, NHII), 5.49 (dd, J1,2 = 2.1, J2,3 = 2.9 Hz, 1 H, 2II-H),
5.21–5.18 (m, 2 H, 2ϫ2Ј-H), 4.84 (d, 1 H, 1II-H), 4.72 (d, J1,2
=
1.9 Hz, 1 H, 1I-H), 4.64, 4.39 (2d, 2J = 11.8 Hz, 2 H, CH2Ph), 4.62,
2
4.50 (2d, J = 11.8 Hz, 2 H, CH2Ph), 4.20–4.14 (m, 2 H, 2ϫ4Јa-
H), 4.11–4.07 (m, 4 H, 2ϫ4Јb-H, incl. q, 4.04, J = 10.4 Hz, 4II-H;
q, 4.00, J = 10.3 Hz, 4I-H), 3.88 (dd, J2,3 = 2.7 Hz, 1 H, 2I-H), 3.81
(dd, J3,4 = 10.6 Hz, 1 H, 3I-H), 3.77 (dd, J3,4 = 10.7 Hz, 1 H, 3II-
H), 3.75–3.71 (m, 2 H, 5I,II-H), 3.68 (s, 3 H, OCH3), 3.65–3.61 (m,
1 H, 1a"-H), 3.36, 3.34 (2t, J = 5.8 Hz, 1 H, 1b"-H), 2.78–2.60 (m,
4 H, CH2CH2), 2.34 (t, J = 7.2 Hz, 2 H, 5ЈЈ-H), 2.28–2.00 (m, 19
H, 2ϫ3Јa,b-H, incl. 5s, 2.16, 2.10, 2.06, 2.05, 2.04, 4CH3CO, CH3),
1.66–1.56 (m, 4 H, 2ЈЈ-H, 4ЈЈ-H), 1.44–1.34 (m, 2 H, 3ЈЈ-H), 1.19,
1.16 (2d, J5,6 = 6.3 Hz, 6 H, 6I,II-H) ppm. 13C NMR (150 MHz,
CDCl3): δ = 206.34 (CH2CO), 174.29 (COOCH3), 171.50
(CH2COO), 170.80, 170.77 (2NHCO), 169.68, 169.59, 169.46,
3 H, SCH2CH3), 1.18, (d, J5,6 = 6.1 Hz, 3 H, 6I-H), 1.17 (d, J5,6
=
6.2 Hz, 3 H, 6II-H) ppm. 13C NMR (150 MHz, CDCl3): δ = 206.34
(CH2CO), 171.68 (CH2COO), 170.86, 170.81 (2NHCO), 169.67,
169.64, 169.57, 169.44 (4CH3CO), 99.72 (JC,H = 166.7 Hz, C-1II),
83.56 (JC,H = 166.7 Hz, C-1I), 76.72 (C-2I), 75.40 (C-3I), 73.14 (C-
3II), 71.34 (CH2Ph), 71.25, 71.14 (2C-2Ј), 70.59 (CH2Ph), 68.82 (C-
5II), 68.38 (C-5I), 67.27 (C-2II), 60.00, 59.96 (2C-4Ј), 52.86 (C-4I),
51.95 (C-4II), 38.01 (CH2CO), 31.03, 30.92 (2C-3Ј), 29.73 (CH3),
28.18 (CH2COO), 25.73 (SCH2CH3), 20.85, 20.84, 20.82, 20.81
(4CH3CO), 17.97 (2 C, C-6I,II), 14.90 (SCH2CH3) ppm. ESI-MS:
m/z: 1025.3972 ([M + Na]+; calcd. 1025.3929). C49H66N2O18
S
169.38 (4CH3CO), 99.61 (JC,H = 160.4 Hz, C-1II), 98.64 (JC,H
=
(1003.5): calcd. C 58.67, H 6.63, N 2.79; found C 58.59, H 6.67, N
2.81.
160.4 Hz, C-1I), 75.09 (C-3I), 74.82 (C-2I), 72.86 (C-3II), 71.31
(CH2Ph), 71.16, 70.97 (2ϫC-2Ј), 70.29 (CH2Ph), 68.59, 67.63 (C-
5I,II), 67.15 (C-1ЈЈ), 67.00 (C-2II), 59.90 (2 C, 2ϫC-4Ј), 52.38 (C-
4I), 51.66 (C-4II), 51.49 (OCH3), 37.93 (CH2CO), 33.81 (C-5ЈЈ),
30.92, 30.76 (2ϫC-3Ј), 29.70 (CH3), 28.64 (CH2COO), 28.06 (C-
2ЈЈ), 25.57 (C-3ЈЈ), 24.35 (C-4ЈЈ), 20.84, 20.77, 20.76, 20.69
(4CH3CO), 17.97, 17.86 (C-6I,II) ppm. ESI-MS: m/z: 1109.4673 ([M
+ Na]+; calcd. 1109.4682). C54H74N2O21 (1086.5): calcd. C 59.66,
H 6.86, N 2.57; found C 59.40, H 6.92, N 2.57.
By Levulinoylation of 15: EDAC (1.23 g, 6.4 mmol) was added to a
solution of the disaccharide 15 (1.93 g, 2.1 mmol) and levulinic acid
(0.74 g, 6.4 mmol) in CH2Cl2 (10 mL), followed by 4-dimethylami-
nopyridine (0.78 g, 6.4 mmol). The mixture was stirred overnight,
when TLC (2:1 hexane/acetone) showed that the reaction was com-
plete. After concentration, the residue was chromatographed
(4:1Ǟ2:1 hexane/acetone) to give 8 (2.05 g, 97%).
994
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© 2007 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Org. Chem. 2007, 988–1000

Glycosylation under Thermodynamic Control
FULL PAPER
showed the reaction to be complete. The mixture was concentrated
and material in the residue was chromatographed (97:3Ǟ 95:5
CH2Cl2/MeOH), to afford ethyl 4-amino-3-O-benzyl-4,6-dideoxy-
α--mannopyranosyl-(1Ǟ2)-4-amino-3-O-benzyl-4,6-dideoxy-1-
1
Eluted next was compound 12 (440 mg, 6%): H NMR (600 MHz,
CDCl3): δ = 6.55 (d, JNH,4 = 8.5 Hz, 1 H, NHI), 6.13 (d, JNH,4
=
7.9 Hz, 1 H, NHII), 5.68 (br. d, J2,3 = 2.9 Hz, 1 H, 2II-H), 5.15–
5.12 (m, 2 H, 2ϫ2Ј-H), 4.79 (d, J1,2 = 1.6 Hz, 1 H, 1I-H), 4.74,
2
4.31 (2d, J = 10.7 Hz, 2 H, CH2Ph), 4.70 (br. s, 1 H, 1I-H), 4.66, thio-α--mannopyranoside (14) (1.37 g, 88 %). 1H NMR
2
4.30 (2d, J = 11.5 Hz, 2 H, CH2Ph), 4.26 (dd, J2,3 = 2.4 Hz, 1 H,
(300 MHz, CDCl3): δ = 5.29 (d, J1,2 = 1.5 Hz, 1 H, 1I-H), 5.00 (d,
J1,2 = 1.6 Hz, 1 H, 1II-H), 4.71–4.45 (m, 4 H, 2CH2Ph), 4.06 (br.
2I-H), 4.18–4.01 (m, 4 H, 2ϫ4Јa,b-H), 4.00–3.96 (m, H-3I, J3,4
=
10.6 Hz, 2 H, 5I-H, incl. dd, 3.99), 3.91 (dd, J3,4 = 10.6 Hz, 1 H, s, 2 H, 2I,II-H), 3.86–3.65 (m, 2 H, 5I,II-H), 3.55, 3.46 (2dd, J2,3
=
3II-H), 3.88–3.84 (m, 1 H, 5II-H), 3.73–3.64 (m, 5 H, 1a"-H, 4I-H 2.9, J3,4 = 9.9 Hz, 2 H, 3I,II-H), 2.89, 2.86 (2t, partially overlapped,
incl. s, 3.68, OCH3), 3.52 (q, J = 10.1 Hz, 4II-H), 3.39, 3.37 (2t, J
= 6.1 Hz, 1 H, 1b"-H), 2.82–2.54 (m, 4 H, CH2CH2), 2.34 (t, J =
J = 10.1 Hz, H-4I,II), 2.70–2.50 (m, 2 H, SCH2CH3), 1.28 (t, J =
7.1 Hz, 3 H, SCH2CH3), 1.26, (2d, J5,6 = 6.2 Hz, 6 H, 6I,II-H) ppm.
7.2 Hz, 2 H, 5ЈЈ-H), 2.20–2.00 (m, 19 H, 2ϫ3Јa,b-H, incl. 5s, 2.06, 13C NMR (75 MHz, CDCl3): δ = 101.29 (C-1II), 83.87 (C-1I),
2.04, 2.02, 2.01, 2.00, 4CH3CO, CH3), 1.70–1.57 (m, 4 H, 2ЈЈ-H,
80.03, 79.66 (C-3I,II), 74.77 (C-2I), 71.53, 71.24 (2CH2Ph), 70.16,
4ЈЈ-H), 1.45–1.35 (m, 2 H, 3ЈЈ-H), 1.22, 1.19 (2d, J5,6 = 6.2 Hz, 6 69.70 (C-5I,II), 66.45 (C-2II), 54.05, 53.26 (C-4I,II), 25.53
H, 6I,II-H) ppm. 13C NMR (150 MHz, CDCl3): δ = 207.78 (SCH2CH3), 18.14, 18.00 (2 C, C-6I,II), 15.01 (SCH2CH3) ppm.
(CH2CO), 174.22 (COOCH3), 172.38 (CH2COO), 170.83, 170.74
(2NHCO), 169.62, 169.51, 169.40, 169.11 (4CH3CO), 98.85 (JC,H
= 166.2 Hz, C-1I), 95.81 (JC,H = 152.1 Hz, C-1II), 73.89 (C-3II),
73.40 (C-3I), 70.99, 70.93 (2ϫC-2Ј), 70.37 (CH2Ph), 69.94 (C-2I),
69.89 (C-5II), 69.75 (CH2Ph), 67.06 (C-1ЈЈ), 67.00 (2 C, C-2II,5I),
59.96, 59.82 (2ϫC-4Ј), 54.43 (C-4II), 53.02 (C-4I), 51.46 (OCH3),
37.96 (CH2CO), 33.81 (C-5ЈЈ), 30.87, 30.77 (2ϫC-3Ј), 29.69 (CH3),
28.80 (CH2COO), 28.28 (C-2ЈЈ), 25.53 (C-3ЈЈ), 24.40 (C-4ЈЈ), 20.76,
20.75, 20.65, 20.58 (4CH3CO), 17.91, 17.87 (C-6I,II) ppm. ESI-MS:
m/z: 1109.4662 ([M + Na]+; calcd. 1109.4682).
ESI-MS: m/z: 533.2681 ([M + 1]+; calcd. 533.2685).
A solution of the foregoing diamino sugar 14 (1.33 g, 2.5 mmol)
and 2,4-di-O-acetyl-3-deoxy--glycero-tetronic acid[13] (1.2 g,
6.25 mmol) in CH2Cl2 (20 mL) was treated with a suspension of
EDAC (1.2 g, 6.25 mmol) in CH2Cl2 (10 mL). The mixture was
stirred for 2 h, when TLC (97:3 CH2Cl2/MeOH) showed that the
reaction was complete. Concentration and chromatography of the
crude product (98:2 CH2Cl2/MeOH) gave the title compound 15
(2.13 g, 96 %); m.p. 112–113 °C (from i-Pr2O containing a few
drops of EtOAc), [α]D = +32 (c = 0.2; CHCl3). 1H NMR
(600 MHz, CDCl3): δ = 5.85 (d, JNH,4 = 9.0 Hz, 1 H, NHII), 5.81
(d, JNH,4 = 9.1 Hz, 1 H, NHI), 5.28 (br. s, 1 H, 1I-H), 5.21–5.19
(m, 2 H, 2ϫ2Ј-H), 4.98 (br. s, 1 H, 1II-H), 4.69, 4.53 (2d, 2J =
5-(Methoxycarbonyl)pentyl 3-O-Benzyl-4-(2,4-di-O-acetyl-3-deoxy-
L
-glycero-tetronamido)-4,6-dideoxy-α-
O-benzyl-4-(2,4-di-O-acetyl-3-deoxy- -glycero-tetronamido)-4,6-di-
deoxy-α- -mannopyranoside (11): Applying the general procedure
D-mannopyranosyl-(1Ǟ2)-3-
L
2
D
11.8 Hz, 2 H, CH2Ph), 4.62, 4.45 (2d, J = 11.9 Hz, 2 H, CH2Ph),
for cleavage of Lev group to 10 gave, after chromatography (3:1
toluene/acetone), the deprotected, amorphous disaccharide 11
(970 mg, 98%). [α]20 = –7 (c = 6; CHCl3). 1H NMR (600 MHz,
4.20–4.16 (m, 3 H, 2ϫ4Јa-H, 2II), 4.12–4.07 (m, 5 H, 2ϫ4Јb-H,
4I,II-H, 2I-H), 4.00–3.98 (m, 1 H, 5I-H), 3.82–3.80 (m, 1 H, 5II-H),
3.75 (dd, J2,3 = 3.0, J3,4 = 10.5 Hz, 1 H, 3II-H), 3.68 (dd, J2,3 = 2.4,
J3,4 = 9.9 Hz, 1 H, 3I-H), 2.66–2.55 (m, 2 H, SCH2CH3), 2.23–2.01
(m, 16 H, 2ϫ3Јa,b-H, incl. 3s, 2.11, 2.09, 2.05, 4CH3CO), 1.28 (t,
J = 7.4 Hz, 3 H, SCH2CH3), 1.20 (d, J5,6 = 5.9 Hz, 3 H, 6I-H), 1.18
(d, J5,6 = 6.1 Hz, 3 H, 6II-H) ppm. 13C NMR (150 MHz, CDCl3): δ
= 170.87, 170.84 (2 ϫ NHCO), 169.68, 169.67, 169.52, 169.43
(4CH3CO), 101.13 (C-1II), 83.67 (C-1I), 75.70 (C-3I), 75.61 (C-2I),
CDCl3): δ = 6.17 (d, JNH,4 = 9.4 Hz, 1 H, NHI), 5.80 (d, JNH,4
9.4 Hz, 1 H, NHII), 5.21–5.17 (m, 2 H, 2ϫ2Ј-H), 5.00 (d, J1,2
=
=
1.7 Hz, 1 H, 1II-H), 4.74 (d, J1,2 = 1.9 Hz, 1 H, 1I-H), 4.70, 4.49
2
2
(2d, J = 11.9 Hz, 2 H, CH2Ph), 4.64, 4.52 (2d, J = 11.9 Hz, 2 H,
CH2Ph), 4.23–4.21 (m, 1 H, 2II-H), 4.19–4.15 (m, 2 H, 2ϫ4Јa-H),
4.13–4.07 (m, 4II,I-H, in that order, J = 10.4 Hz, 4 H, 2ϫ4Јb-H,
incl. 2q, 4.11), 3.98 (br. t, 1 H, 2I-H), 3.77–3.66 (m, 3II-H; s, 3.68, 75.30 (C-3II), 71.13, 71.05 (2ϫC-2Ј), 71.08, 70.71 (2CH2Ph), 68.46
OCH3, J2,3 = 2.8 Hz, J3,4 = 10.4 Hz, 3I-H; dd, 3.71, J2,3 = 3.2 Hz, (C-5I), 68.20 (C-5II), 66.43 (C-2II), 59.96, 59.91 (2ϫC-4Ј), 52.34 (C-
J3,4 = 10.4 Hz, 6 H, 5I,II-H, incl. dd, 3.76), 3.66–3.62 (m, 1 H, 1a"-
H), 3.38, 3.36 (2ϫt, J = 5.8 Hz, 1 H, 1b"-H), 2.54 (br. s, 1 H, 2II-
OH), 2.34 (t, J = 7.2 Hz, 2 H, 5ЈЈ-H), 2.25–2.04 (m, 16 H, 2ϫ3Јa,b-
H, incl. 4s, 2.12, 2.08, 2.06, 2.04, 4CH3CO), 1.70–1.55 (m, 4 H, 2ЈЈ-
H, 4ЈЈ-H), 1.46–1.31 (m, 2 H, 3ЈЈ-H), 1.21 (d, J5,6 = 6.3 Hz, 3 H,
6II-H), 1.16 (d, J5,6 = 6.3 Hz, 6 H, 6I-H) ppm. 13C NMR (150 MHz,
CDCl3): δ = 174.37 (COOCH3), 170.80 (2 C, 2NHCO), 169.72,
169.62, 169.46, 169.40 (4CH3CO), 101.00 (C-1II), 98.82 (C-1I),
75.59 (C-3I), 75.12 (C-3II), 73.83 (C-2I), 71.24 (CH2Ph), 71.13,
70.99 (2ϫC-2Ј), 70.49 (CH2Ph), 68.03, (C-5I), 67.85 (C-5II), 67.04
(C-1ЈЈ), 66.24 (C-2II), 59.94, 59.26 (2ϫC-4Ј), 52.00 (C-4I), 51.51
(OCH3), 51.14 (C-4II), 33.81 (C-5ЈЈ), 30.91, 30.81 (2ϫC-3Ј), 28.60
(C-2ЈЈ), 25.59 (C-3ЈЈ), 24.31 (C-4ЈЈ), 20.84, 20.78, 20.76, 20.67
(4CH3CO), 17.95, 17.75 (C-6I,II) ppm. ESI-MS: m/z: 1011.4345 ([M
+ Na]+; calcd. 1011.4314). C49H68N2O19 (988.5): calcd. C 59.50, H
6.93, N 2.92; found C 59.35, H 6.96, N 2.79.
4I), 51.30 (C-4II), 30.91, 30.83 (2ϫC-3Ј), 25.66 (SCH2CH3), 20.84,
20.81, 20.79 (4 C, 4CH3CO), 17.87, 17.79 (C-6I,II), 14.87
(SCH2CH3) ppm. ESI-MS: m/z: 927.3522 ([M + Na]+; calcd.
927.3561). C44H60N2O16S (904.5): calcd. C 58.39, H 6.68, N 3.10;
found C 58.97, H 6.71, N 3.03.
Ethyl 4-Azido-3-O-benzyl-4,6-dideoxy-2-O-methyl-α-
anosyl-(1Ǟ2)-4-azido-3-O-benzyl-4,6-dideoxy-1-thio-α-
D
-mannopyr-
-manno-
D
pyranoside (16): MeI (ca. 1 mL, 13.5 mmol) was added to a stirred
mixture of disaccharide 13[19] (5.9 g, 11.1 mmol) and powdered
KOH (1.87 g, 33.3 mmol) in Me2SO (15 mL). After 1 h, TLC (6:1
hexane/acetone) showed absence of the starting material and for-
mation of one product. CH2Cl2 (50 mL) was added, and the mix-
ture was filtered into a separating funnel containing aq. 10 %
AcOH. After partitioning, the combined organic layers were con-
centrated, and chromatography of the residue (95:5 hexane/ace-
tone) gave amorphous 16 (5.8 g, 97%), [α]D = +150 ( c = 0; CHCl3).
1H NMR (300 MHz, CDCl3): δ = 5.11 (d, J1,2 = 1.2 Hz, 2 H, 1I-
H), 4.85 (d, J1,2 = 1.6 Hz, 1 H, 1II-H), 4.72, 4.67 (2d, 2J = 11.7 Hz,
Ethyl 3-O-Benzyl-4-(2,4-di-O-acetyl-3-deoxy-
L
-glycero-tetronami-
-mannopyranosyl-(1Ǟ2)-3-O-benzyl-4-(2,4-di-
-glycero-tetronamido)-4,6-dideoxy-1-thio-α-
do)-4,6-dideoxy-α-
O-acetyl-3-deoxy-
D
2
L
D
-
2 H, CH2Ph), 4.69, 4.54 (2d, J = 11.4 Hz, 2 H, CH2Ph), 3.96 (dd,
mannopyranoside (15): Hydrogen sulfide was passed for 30 min at
room temperature through a solution of azido sugar 13[19] (1.74 g,
2.98 mmol) in 2:1 pyridine/H2O (100 mL) and kept overnight in a
J2,3 = 2.8 Hz, 1 H, 2I-H), 3.87–3.77 (m, 1 H, 5I-H), 3.70 (dd, J2,3
= 3.1, J3,4 = 9.6 Hz, 1 H, 3II-H), 3.65 (dd, J3,4 = 9.9 Hz, 1 H, 3I-
H), 3.58–3.43 (m, 4II-H, J = 10.2 Hz, 2 H, 5II-H, incl. t, 3.48), 3.37
loosely closed vessel at 40 °C, when TLC (95:5 DCM/MeOH) (dd, 1 H, 2II-H), 3.27 (t, J = 9.9 Hz, 4I-H), 3.21 (s, 3 H, OCH3),
Eur. J. Org. Chem. 2007, 988–1000
© 2007 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
995

R. Adamo, P. Kovácˇ
FULL PAPER
2.66–2.48 (m, 2 H, SCH2CH3), 1.30–1.23 (m, 6II-H, J5,6 = 6.1 Hz,
pyranosyl-(1Ǟ2)-3-O-benzyl-4-(2,4-di-O-acetyl-3-deoxy-
L-glycero-
6I-H; d, 1.27, J5,6 = 6.1 Hz, 9 H, SCH2CH3, incl. d, 1.29) ppm. 13
C
tetronamido)-4,6-dideoxy-α- (19) and β- -Mannopyranoside (20):
D
NMR (75 MHz, CDCl3): δ = 99.11 (C-1II), 83.41 (C-1I), 78.49 (C-
Thioglycoside 18 (1.2 g, 1.3 mmol) and 5-(methoxycarbonyl)penta-
3I), 77.40 (C-3II), 76.57 (C-2II), 75.54 (C-2I), 72.34, 72.02 nol[36] (0.25 g, 1.7 mmol) were treated according to Procedure B to
(2CH2Ph), 67.79 (C-5II), 67.42 (C-5I), 64.56 (C-4I), 64.02 (C-4II), give, after chromatography 4:1 (toluene/acetone), first the α-linked
58.86 (OCH3), 25.46 (SCH2CH3), 18.43 (C-6II), 18.39 (C-6I), 14.81
(SCH2CH3) ppm. ESI-MS: m/z: 621.2503 ([M + Na]+; calcd.
621.2471). C29H38N6O6S (598.3): calcd. C 58.18, H 6.40, N 14.04;
found C 58.27, H 6.56, N 14.03.
product 19 (900 mg, 63%): [α]D = –7 (c = 0.8; CHCl3). H NMR
(60 MHz, CDCl3): δ = 6.26 (d, JNH,4 = 9.5 Hz, 1 H, NHI), 5.73 (d,
JNH,4 = 9.1 Hz, 1 H, NHII), 5.22–5.10 (m, 2 H, 2ϫ2Ј-H), 4.97 (d,
J1,2 = 1.7 Hz, 1 H, 1II-H), 4.72–4.50 (m, 1 H, 1I-H, J1,2 = 2.0 Hz,
1
5 H, 2CH2Ph, incl. d, 4.71), 4.21–4.06 (m, 6 H, 2ϫ4Јa,b-H, 4I,II
-
Ethyl 3-O-Benzyl-4-(2,4-di-O-acetyl-3-deoxy-
amido)-4,6-dideoxy-2-O-methyl-α- -mannopyranosyl-(1Ǟ2)-3-O-
benzyl-4-(2,4-di-O-acetyl-3-deoxy- -glycero-tetronamido)-4,6-dide-
oxy-1-thio-α- -mannopyranoside (18): Azido sugar 16 (5.7 g,
L-glycero-tetron-
H), 4.00 (dd, J2,3 = 2.5 Hz, 1 H, 2I-H), 3.78 (dd, J3,4 = 10.6 Hz, 3I-
H), 3.75–3.63 (m, 8 H, 2II-H, 3II-H, 5I,II-H, 1ЈЈa-H, incl. 3.67, s, 3
H, COOCH3), 3.39, 3.37 (2t, J = 5.7 Hz, 1 H, 1ЈЈb-H), 3.27 (s, 3
H, 2II-OCH3), 2.34 (t, J = 7.4 Hz, 2 H, 5ЈЈ-H), 2.27–2.02 (m, 16 H,
2ϫ3Јa,b-H, incl. 4s, 2.10, 2.05, 2.04, 2.02, 4CH3CO), 1.73–1.55 (m,
4 H, 4ЈЈ-H, 2ЈЈ-H), 1.48–1.33 (m, 2 H, 3ЈЈ-H), 1.22 (d, J5,6 = 6.2 Hz,
6I-H), 1.16 (d, J5,6 = 6.2 Hz, 6II-H) ppm. 13C NMR (150 MHz,
CDCl3): δ = 174.45 (COOCH3), 170.82, 170.78 (2NHCO), 169.82,
169.53, 169.35, 169.29 (4CH3CO), 99.59 (JC,H = 170.3 Hz, C-1II),
98.91 (JC,H = 169.8 Hz, C-1I), 76.20 (C-3I), 75.17 (C-2II), 74.67
(C-3II), 73.51 (C-2I), 71.64 (CH2Ph), 71.22, 70.01 (2ϫC-2Ј), 70.26
(CH2Ph), 68.70 (C-5II), 68.76 (C-5I), 66.96 (C-1ЈЈ), 59.97, 59.94
(2ϫC-4Ј), 58.85 (OCH3-2II), 52.17 (C-4II), 51.78 (C-4I), 51.54 (CO-
OCH3), 33.83 (C-5ЈЈ), 30.94, 30.81 (2ϫC-3Ј), 28.61 (C-2ЈЈ), 25.59
(C-3ЈЈ), 24.30 (C-4ЈЈ), 20.87, 20.78, 20.76, 20.65 (4CH3CO), 17.94
(2 C, C-6I,II) ppm. ESI-MS: m/z: 1025.4480 ([M + Na]+; calcd.
1025.4447). C50H70N2O19 (1002.5): calcd. C 59.87, H 7.03, N 2.79;
found C 59.70, H 7.21, N 2.86.
D
L
D
9.51 mmol) in 2:1 pyridine/H2O (300 mL) was treated with H2S as
described for the preparation of 14, and chromatography of the
crude product (97:3Ǟ95:5 DCM/MeOH) afforded ethyl 4-amino-
3-O-benzyl-4,6-dideoxy-2-O-methyl-α--mannopyranosyl-(1Ǟ2)-
4-amino-3-O-benzyl-4,6-dideoxy-1-thio-α--mannopyranoside (17,
5.01 g, 97%). 1H NMR (300 MHz, CDCl3): δ = 5.25 (d, J1,2
=
1.5 Hz, 1 H, 1I-H), 4.99 (d, J1,2 = 1.8 Hz, 1 H, 1II-H), 4.71–4.51
(m, 4 H, 2CH2Ph), 4.08 (dd, J2,3 = 2.5 Hz, 1 H, 2I-H), 3.88–3.78
(m, 1 H, 5I-H), 3.68–3.45 (m, 3I-H, J2,3 = 3.8, J3,4 = 9.5 Hz, 3II-H;
dd, 3.47, J3,4 = 9.9 Hz, 4 H, 5II-H, 2II-H, incl. dd, 3.55), 3.33 (s, 3
H, OCH3), 2.93 (t, partially overlapped, J = 9.5 Hz, 4II-H), 2.88 (t,
partially overlapped, J = 9.8 Hz, 4I-H), 2.70–2.50 (m, 2 H,
SCH2CH3), 1.31–1.25 (m, 6II-H, J5,6 = 6.5 Hz, 6I-H; d, 1.27, J5,6
=
6.1 Hz, 9 H, SCH2CH3, incl. d, 1.29) ppm. 13C NMR (75 MHz,
CDCl3): δ = 98.21 (C-1II), 83.79 (C-1I), 80.29 (C-3I), 78.97 (C-3II),
75.71 (C-2II), 74.22 (C-2I), 71.64, 71.25 (2CH2Ph), 70.31 (C-5II),
70.06 (C-5I), 58.85 (OCH3), 54.07 (C-4I), 53.47 (C-4II), 25.36
(SCH2CH3), 18.03, 17.99 (C-6I,II), 14.91 (SCH2CH3) ppm. ESI-
MS: m/z: 547.2822 ([M + 1]+; calcd. 527.2842).
Eluted next was β-glycoside 20 (500 mg, 35 %): 1H NMR
(600 MHz, CDCl3): δ = 6.14 (d, JNH,4 = 8.8 Hz, 1 H, NHI), 5.92
(d, JNH,4 = 9.5 Hz, 1 H, NHII), 5.24 (dd, J2Ј,3Јa = 8.0, J2Ј,3Јb
=
4.4 Hz, 1 H, 2Ј-H), 5.16 (dd, J2Ј,3Јa = 8.0, J2Ј,3Јb = 4.8 Hz, 1 H, 2Ј-
H), 5.03 (d, J1,2 = 1.7 Hz, 1 H, 1II-H), 4.69, 4.51 (2d, 2J = 12.0 Hz,
2
A solution of the foregoing diamino sugar 17 (4.8 g, 8.78 mmol)
and 2,4-di-O-acetyl-3-deoxy--glycero-tetronic acid[13] (4.5 g,
22 mmol) in CH2Cl2 (60 mL) was treated with EDAC (4.22 g,
22 mmol) as described for the preparation of 15. After 2 h, when
TLC (97:3 CH2Cl2/MeOH) showed that all starting material had
been consumed, the mixture was concentrated, and chromatog-
raphy (98:2 CH2Cl2/MeOH) gave the coupling product 18 (7.26 g,
90 %); m.p. 173–174 °C (from iPrO2 containing a few drops of
EtOAc). [α]D = –175 (c = 0.2; CHCl3). 1H NMR (600 MHz,
2 H, CH2Ph), 4.66, 4.50 (2d, J = 11.4 Hz, 2 H, CH2Ph), 4.40 (d,
J1,2 = 0.7 Hz, 1 H, 1I-H), 4.22 (dd, J2,3 = 2.5 Hz, 2I-H), 4.21–4.02
(m, 6 H, 2 ϫ 4Јa,b-H, 5II-H, 4II-H), 3.87–3.81 (m, 4I-H, J =
10.1 Hz, 2 H, 1ЈЈa-H, incl. q, 3.84), 3.76 (dd, J2,3 = 2.9, J3,4
=
10.6 Hz, 1 H, 3II-H), 3.74 (dd, 1 H, 2II-H), 3.69 (dd, J3,4 = 10.4 Hz,
1 H, 3I-H), 3.65 (s, 3 H, COOCH3), 3.46, 3.44 (2t, J = 6.9 Hz, 1
H, 1ЈЈb-H), 3.21 (s, 3 H, 2II-OCH3), 2.30 (t, J = 7.4 Hz, 2 H, 5ЈЈ-
H), 2.26–2.00 (m, 16 H, 2ϫ3Јa,b-H, incl. 4s, 2.10, 2.06, 2.04, 2.02,
4CH3CO), 1.67–1.56 (m, 4 H, 4ЈЈ-H, 2ЈЈ-H), 1.41–1.33 (m, 2 H,
3ЈЈ-H), 1.28 (d, J5,6 = 6.2 Hz, 6I-H), 1.13 (d, J5,6 = 6.2 Hz, 6II-H)
ppm. 13C NMR (150 MHz, CDCl3): δ = 173.92 (COOCH3),
169.73, 169.42, 169.39, 169.26 (6 C, 2NHCO, 4CH3CO), 100.05
(JC,H = 152.8 Hz, C-1I), 99.79 (JC,H = 169.9 Hz, C-1II), 78.20 (C-
3I), 75.47 (C-3II), 75.30 (C-2II), 72.41 (C-2I), 71.75 (CH2Ph), 71.10,
70.99 (2ϫC-2Ј), 70.94 (C-5I), 70.23 (CH2Ph), 69.82 (C-1ЈЈ), 68.01
(C-5II), 59.97, 59.83 (2 ϫ C-4Ј), 58.77 (OCH3-2II), 53.32 (C-4I),
51.57 (C-4II), 51.41 (COOCH3), 33.71 (C-5ЈЈ), 30.91, 30.74 (2ϫC-
3Ј), 29.06 (C-2ЈЈ), 25.27 (C-3ЈЈ), 24.38 (C-4ЈЈ), 20.84, 20.75, 20.72,
20.62 (4CH3CO), 17.92 (C-6I), 17.71 (C-6II) ppm. ESI-MS: m/z:
1025.4458 ([M + Na]+; calcd. 1025.4447).
CDCl3): δ = 5.86 (d, JNH,4 = 9.3 Hz, 1 H, NHII), 5.78 (d, JNH,4
=
8.9 Hz, 1 H, NHI), 5.24 (d, J1,2 = 1.0 Hz, 1 H, 1I-H), 5.22–5.20 (m,
2 H, 2ϫ2Ј-H), 4.94 (d, J1,2 = 1.5 Hz, 1 H, 1II-H), 4.71–4.50 (m, 4
H, 2CH2Ph), 4.22–4.06 (m, 7 H, 2ϫ4Јa,b-H, 4II-H, 2 I-H, 4I-H, in
that order), 4.04–3.99 (m, 1 H, 5I-H), 3.80–3.74 (m, 3II-H, J2,3
=
2.8, J3,4 = 10.9 Hz, 2 H, 5II-H, incl. dd, 3.79), 3.71–3.69 (m, 3I-H,
J2,3 = 2.5, J3,4 = 10.4 Hz, 2 H, 2II-H, incl. dd, 3.70), 3.32 (s, 3 H,
OCH3), 2.67–2.55 (m, 2 H, SCH2CH3), 2.28–2.02 (m, 16 H,
2ϫ3Јa,b-H, incl. 4s, 2.10, 2.09, 2.05, 2.04, 4CH3CO), 1.28 (t, J =
7.4 Hz, 3 H, SCH2CH3), 1.22 (d, J5,6 = 6.2 Hz, 6I-H), 1.18 (d, J5,6
= 6.2 Hz, 6II-H) ppm. 13C NMR (150 MHz, CDCl3): δ = 99.70 (C-
1II), 83.75 (C-1I), 76.26 (C-3I), 75.38 (C-2II), 75.17 (C-2I), 74.83 (C-
3II), 71.41 (CH2Ph), 71.20, 70.05 (2ϫC-2Ј), 70.49 (CH2Ph), 68.84
(C-5II), 68.37 (C-5I), 59.97, 59.90 (2ϫC-4Ј), 58.85 (OCH3), 52.85
(C-4II), 51.96 (C-4I), 30.93, 30.81 (2ϫC-3Ј), 25.62 (SCH2CH3),
20.87, 20.81, 20.78 (4 C, 4CH3CO), 17.99 (C-6II), 17.86 (C-6I),
14.88 (SCH2CH3) ppm. ESI-MS: m/z: 941.3650 ([M + Na]+; calcd.
941.3718). C45H62N2O16S (918.4): calcd. C 58.88, H 6.80, N 3.05;
found C 59.07, H 6.66, N 3.04.
5-(Methoxycarbonyl)pentyl 4-(3-Deoxy-
dideoxy-2-O-methyl-α- -mannopyranosyl-(1Ǟ2)-4-(3-deoxy-
glycero-tetronamido)-4,6-Dideoxy-α- -mannopyranoside (22): A
L-glycero-tetronamido)-4,6-
D
L-
D
solution of 19 (1.15 g, 1.15 mmol) in MeOH (50 mL) was made
strongly alkaline to litmus by addition of 0.1  methanolic NaOMe
and kept at room temperature overnight, when TLC (9:1 CH2Cl2/
MeOH) showed the reaction to be complete. The mixture was neu-
tralized with amberlite IR-120 (H+-form), filtered, the filtrate was
concentrated and chromatography of the residue (19:1 CH2Cl2/
MeOH) gave the intermediate product, 5-(methoxycarbonyl)pentyl
5-(Methoxycarbonyl)pentyl 3-O-Benzyl-4-(2,4-di-O-acetyl-3-deoxy-
L
-glycero-tetronamido)-4,6-dideoxy-2-O-methyl-α-
D-manno-
996
www.eurjoc.org
© 2007 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Org. Chem. 2007, 988–1000

Glycosylation under Thermodynamic Control
FULL PAPER
3-O-benzyl-4-(3-deoxy--glycero-tetronamido)-4,6-dideoxy-2-O-
methyl-α--mannopyranosyl-(1Ǟ2)-3-O-benzyl-4-(3-deoxy--
CHCl3). 1H NMR (600 MHz, CDCl3): δ = 6.16 (d, JNH,4 = 5.9 Hz,
1 H, NHIII), 5.93 (d, JNH,4 = 9.7 Hz, 1 H, NHI), NHII not ob-
served, 5.41 (dd, J1,2 = 1.9, J2,3 = 2.6 Hz, 1 H, 2III-H), 5.22–5.16
(m, 3 H, 3ϫ2Ј-H), 5.03 (br. s, 1 H, 1II-H), 4.72 (d, J1,2 = 1.4 Hz,
glycero-tetronamido)-4,6-dideoxy-α--mannopyranoside 21
1
(855 mg, 90%): H NMR (600 MHz, CDCl3): δ = 7.06 (d, JNH,4
=
9.6 Hz, 1 H, NHI), 6.92 (d, JNH,4 = 9.8 Hz, 1 H, NHII), 5.05 (m, 1 1 H, 1I-H), 4.68–4.29 (m, 6 H, 3CH2Ph), 4.22–3.98 (m, 10 H,
H, 2Ј-H), 4.95–4.94 (m, 2 H, 2Ј-H, incl. 4.95, s, 1II-H), 4.73 (s, 1 3ϫ4Јa,b-H, incl. 4II-H, 4I-H, 2II-H, 4III-H, in that order), 3.91 (m,
H, 1I-H), 4.64, 4.50 (2d, 2J = 11.8 Hz, 2 H, CH2Ph), 4.59, 4.55 (2d, 1 H, 2I-H), 3.78–3.62 (m, 3I-H; 3.67, s, OCH3, J2,3 = 3.1, J3,4
2J = 11.5 Hz, 2 H, CH2Ph), 4.31 (m, 1 H, 4Јa-H), 4.24 (m, 1 H, 10.4 Hz, 3III-H; dd, 3.77, J2,3 = 3.1, J3,4 = 10.4 Hz, 3II-H; dd, 3.73,
=
4Јa-H), 4.11–4.05 (m, 2 H, 4II-H, 4I-H, in that order), 3.95 (br. s,
1 H, 2I-H), 3.81–3.52 (m, 11 H, 2ϫ4Јb-H, 3I-H, 3II-H, 5II-H, 5I-
H, 2II-H, 1ЈЈa-H, in that order, incl. 3.65, s, COOCH3), 3.37–3.34
(m, 1 H, 1ЈЈb-H), 3.24 (s, 3 H, 2II-OCH3), 2.32 (t, J = 7.4 Hz, 2 H,
5ЈЈ-H), 2.07–1.99 (m, 2 H, 2ϫ3Јa-H), 1.81–1.79 (m 2 H, 2ϫ3Јb-
J2,3 = 2.6, J3,4 = 10.7 Hz, 10 H, 5III-H, 5II-H, 5I-H, 1a"-H, in that
order, incl. dd, 3.78), 3.37, 3.36 (2t, J = 5.7 Hz, 1 H, 1b"-H), 2.76–
2.61 (m, 4 H, CH2CH2), 2.33 (t, J = 7.1 Hz, 2 H, 5ЈЈ-H), 2.28–2.00
(m, 27 H, 3ϫ3Јa,b-H, incl. 7s, 2.15, 2.14, 2.06, 2.05, 2.04, 2.02,
2.01, 6CH3CO, CH3), 1.70–1.52 (m, 4 H, 2ЈЈ-H, 4ЈЈ-H), 1.45–1.31
H), 1.67–1.54 (m, 4 H, 4ЈЈ-H, 2ЈЈ-H), 1.43–1.30 (m, 2 H, 3ЈЈ-H), (m, 2 H, 3ЈЈ-H), 1.18 (d, J5,6 = 6.2 Hz, 3 H, 6III-H), 1.15 (d, J5,6
=
1.21 (d, J5,6 = 6.1 Hz, 6I-H), 1.16 (d, J5,6 = 6.1 Hz, 6II-H) ppm. 13 6.2 Hz, 3 H, 6I-H), 1.11 (d, J5,6 = 6.2 Hz, 6 H, 6II-H) ppm. 13C
C
NMR (150 MHz, CDCl3): δ = 174.45, 174.70, 174.25 (COOCH3, NMR (150 MHz, CDCl3): δ = 205.99 (CH2CO), 174.18 (CO-
2NHCO), 99.34 (C-1II), 98.71 (C-1I), 76.25 (C-3I), 75.52 (C-3II), OCH3), 171.28 (CH2COO), 170.57, 170.51, 170.46 (3NHCO),
75.48 (C-2II), 74.04 (C-2I), 71.89 (CH2Ph), 71.34, (2 C, 2ϫC-2Ј),
70.85 (CH2Ph), 68.56 (C-5II), 68.78 (C-5I), 67.17 (C-1ЈЈ), 60.16,
169.46, 169.42, 169.33, 169.25, 169.15 (6 C, 6CH3CO), 100.57 (JC,H
= 170.3 Hz, C-1II), 98.88 (JC,H = 170.4 Hz, C-1I), 98.15 (JC,H
=
60.02 (2ϫC-4Ј), 58.79 (OCH3-2II), 51.96 (C-4I), 51.49 (COOCH3), 169.5 Hz, C-1III), 75.31 (C-3III), 74.67 (C-2I), 73.99 (C-2II), 73.75
51.47 (C-4II), 35.79, 35.67 (2ϫC-3Ј), 33.74 (C-5ЈЈ), 28.76 (C-2ЈЈ),
(C-3II), 73.23 (C-3I), 71.25, (CH2Ph), 71.21, 70.08, 70.01 (3ϫC-2Ј),
25.55 (C-3ЈЈ), 24.38 (C-4ЈЈ), 17.91, 17.87 (C-6I,II) ppm. ESI-MS: 70.69, 70.47 (2 ϫ CH2Ph), 68.74, 68.71 (C-5II,III), 67.80 (C-5I),
m/z: 857.4017 ([M + Na]+; calcd. 857.4048).
67.23 (C-2III), 67.13 (C-1ЈЈ), 60.06, 59.94, 59.93 (3ϫC-4Ј), 52.12
(C-4I), 51.76 (C-4II), 51.65 (C-4III), 51.58 (OCH3), 38.00 (CH2CO),
33.86 (C-5ЈЈ), 30.96, 30.85 (3 C, 3 ϫ C-3Ј), 29.75 (CH3), 28.63
(CH2COO), 28.13 (C-2ЈЈ), 25.62 (C-3ЈЈ), 24.35 (C-4ЈЈ), 20.94, 20.85,
20.81, 20.79, 20.69 (6 C, 6CH3CO), 18.17 (C-6II), 18.00 (C-6I),
17.88 (C-6III) ppm. ESI-MS: m/z: 1530.6467 ([M + Na]+; calcd.
1530.6418). C75H101N3O29 (1506.7): calcd. C 59.87, H 6.94, N 2.76;
found C 59.59, H 6.83, N 2.99.
A mixture of the foregoing dibenzyl ether 21 (550 mg, 0.66 mmol)
and Escat 103 (500 mg) in MeOH (15 mL) was stirred overnight
under hydrogen, when TLC (85:15 CH2Cl2/MeOH) showed that
the reaction was complete. The mixture was filtered through a celite
pad, the filtrate was concentrated, and a solution of the residue
was eluted from a small silica gel column (85:15 CH2Cl2/MeOH).
Fractions containing the desired material were pooled and, after
concentration, a solution the residue in deionized water was filtered
through a syringe filter (0.45 µm porosity) and freeze-dried, to give
the disaccharide 22, which was obtained as a white amorphous
5-(Methoxycarbonyl)pentyl 3-O-Benzyl-4-(2,4-di-O-acetyl-3-deoxy-
L
-glycero-tetronamido)-4,6-dideoxy-2-O-levulinoyl-α-
pyranosyl-(1Ǟ2)-bis[3-O-benzyl-4-(2,4-di-O-acetyl-3-deoxy-
glycero-tetronamido)-4,6-dideoxy-α-
D-manno-
L
-
1
solid (380 mg, 90%): H NMR (600 MHz, D2O): δ = 5.17 (d, J1,2
D
-mannopyranosyl]-3-O-benzyl-
= 1.7 Hz, 1 H, 1II-H), 4.92 (d, J1,2 = 1.6 Hz, 1 H, 1I-H), 4.30, 4.28
4-(2,4-di-O-acetyl-3-deoxy-L-glycero-tetronamido)-4,6-dideoxy-α-D
-
(2dd, J2Ј,3Јa = 8.8, J2Ј,3Јb = 4.7 Hz, 2 H, 2ϫ2Ј-H), 4.09 (dd, J2,3
=
mannopyranoside (25)
3.4, J3,4 = 10.7 Hz, 1 H, 3II-H), 4.06 (dd, J2,3 = 3.2, J3,4 = 10.3 Hz,
1 H, 3I-H), 3.96 (dd, 1 H, 2I-H), 3.94–3.82 (m, 4II-H, J = 10.2 Hz,
4I-H; 3.84, t, J = 10.5 Hz, 4 H, 5I,II-H, incl. 3.91, t), 3.77 (dd, 1 H,
2II-H), 3.75–3.73 (m, 4 H, 2 ϫ 4Јa,b-H), 3.71, 3.70 (2 ϫ t, J =
6.2 Hz, 1ЈЈa-H), 3.68 (s, 1 H, COOCH3), 3.54, 3.53 (2t, J = 6.2 Hz,
1ЈЈb-H), 3.49 (s, 3 H, 2II-OCH3), 2.40 (t, J = 7.4 Hz, 2 H, 5ЈЈ-H),
2.06–2.00 (m, 2 H, 2ϫ3Јa-H), 1.88–1.83 (m, 2 H, 2ϫ3Јb-H), 1.65–
1.59 (m, 4 H, 4ЈЈ-H, 2ЈЈ-H), 1.41–1.36 (m, 2 H, 3ЈЈ-H), 1.19 (d,
J5,6 = 6.0 Hz, 6I-H), 1.17 (d, J5,6 = 6.2 Hz, 6II-H) ppm. 13C NMR
(150 MHz, D2O): δ = 180.32, 180.14, 180.02 (COOCH3, 2NHCO),
101.85 (C-1II), 101.10 (C-1I), 81.69 (C-2II), 81.00 (C-2I), 71.72,
71.70 (2ϫC-2Ј), 70.68 (C-1ЈЈ), 70.66 (C-5II), 70.35 (C-5I), 70.30 (C-
3I), 70.20 (C-3II), 61.49 (OCH3-2II), 60.58 (2 C, 2ϫC-4Ј), 55.92 (C-
4II), 55.81 (C-4I), 54.86 (COOCH3), 38.72, 38.68 (2ϫC-3Ј), 36.34
(C-5ЈЈ), 30.81 (C-2ЈЈ), 27.60 (C-3ЈЈ), 27.33 (C-4ЈЈ), 19.60 (C-6II),
19.54 (C-6I) ppm. ESI-MS: m/z: 677.3000 ([M + Na]+; calcd.
673.3109).
From Disaccharide 11 and Chloride 9: A mixture of acceptor 11
(160 mg, 0.16 mmol), donor 9 (203 mg, 0.21 mmol) and 4-Å MS
(150 mg) in CH2Cl2 (3 mL) was stirred under nitrogen for 30 min.
A solution of AgOTf (54 mg, 0.21 mmol) and 2,6-di-tert-butyl-4-
methylpyridine (34 mg, 0.17 mmol) was added dropwise and the
mixture was stirred for 2 h, when TLC (hexane/acetone, 1:1)
showed the reaction to be complete. The mixture was filtered
through a celite pad into a separating funnel and partitioned be-
tween CH2Cl2 and aq Na2S2O3/aq NaHCO3. The combined or-
ganic layers were dried, concentrated, and chromatography
(4:1Ǟ3:2 hexane/acetone) gave a, 2:1 mixture of products 25 and
27. Subsequent chromatography (98:2 toluene/MeOH) gave 25
(113 mg, 35%) and 27 (60 mg, 18%).
1
Compound 25: [α]D = –28 (c = 0.2; CHCl3). H NMR (600 MHz,
CDCl3): δ = 6.15 (d, JNH,4 = 9.4 Hz, 1 H, NHI), 5.90 (br. s, 2 H,
NHIII,IV), 5.72 (br. s, 1 H, NHII), 5.43 (dd, J1,2 = 2.3, J2,3 = 2.5 Hz,
1 H, 2IV-H), 5.21–5.15 (m, 4 H, 4ϫ2Ј-H), 5.03 (d, J1,2 = 2.4 Hz, 1
H, 1III-H), 4.98 (br. s, 1 H, 1II-H), 4.74 (br. s, 1 H, 1IV-H), 4.71 (d,
J1,2 = 1.6 Hz, 1 H, 1I-H), 4.66–4.29 (m, 8 H, 4CH2Ph), 4.20–4.00
(m, 4IV-H, J = 10.1 Hz, 12 H, 4ϫ4Јa,b-H, 4I-H, 2II,III-H, incl. q,
4.01), 3.90 (br. s, 1 H, 2I-H), 3.78–3.72 (m, 3I,II-H, J2,3 = 2.4, J3,4
= 10.3 Hz, 3III,IV-H; dd, 3.74, J2,3 = 2.4, J3,4 = 10.6 Hz, 5 H, 5IV-
5-(Methoxycarbonyl)pentyl 3-O-Benzyl-4-(2,4-di-O-acetyl-3-deoxy-
L
-glycero-tetronamido)-4,6-dideoxy-2-O-levulinoyl-α-
pyranosyl-(1Ǟ2)-3-O-benzyl-4-(2,4-di-O-acetyl-3-deoxy-
tetronamido)-4,6-dideoxy-α- -mannopyranosyl-(1Ǟ2)-3-O-benzyl-
4-(2,4-di-O-acetyl-3-deoxy- -glycero-tetronamido)-4,6-dideoxy-α-
mannopyranoside (23): This compound was prepared from glycosyl
D
-manno
L-glycero-
D
L
D-
donor 5 (153 mg, 0.26 mmol) and glycosyl acceptor 11 (220 mg, H, incl. dd, 3.77), 3.71–3.61 (m, 7 H, 5I–III-H, 1a"-H, incl. 3.68, s,
0.22 mmol) according to procedure A for glycosylation (TLC 1:1
hexane/acetone). Chromatography (8:1 toluene/acetone) afforded
the syrupy trisaccharide 23 (255 mg, 76%). [α]D = –5.5 (c = 0.4;
OCH3), 3.37, 3.35 (2t, J = 5.9 Hz, 1 H, 1b"-H), 2.71–2.60 (m, 4 H,
CH2CH2), 2.32 (t, J = 7.1 Hz, 2 H, 5ЈЈ-H), 2.25–2.00 (m, 35 H,
4ϫ3Јa,b-H, incl. 9s, 2.14, 2.10, 2.09, 2.06, 2.05, 2.04, 2.03, 2.02,
Eur. J. Org. Chem. 2007, 988–1000
© 2007 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
997

R. Adamo, P. Kovácˇ
2.01, 8CH3CO, CH3), 1.70–1.54 (m, 4 H, 2ЈЈ-H, 4ЈЈ-H), 1.45–1.30 (24) in virtually theoretical yield (ca. 180 mg): 1H NMR (600 MHz,
FULL PAPER
(m, 2 H, 3ЈЈ-H), 1.18 (d, J5,6 = 6.3 Hz, 3 H, 6I-H), 1.16 (d, J5,6
=
CDCl3): δ = 6.20 (d, JNH,4 = 8.5 Hz, 1 H, NHI), 5.81 (d, JNH,4
=
6.2 Hz, 3 H, 6II-H), 1.12 (d, J5,6 = 6.1 Hz, 3 H, 6IV-H), 1.11 (d, J5,6 8.0 Hz, 1 H, NHII), NHIII not observed, 5.22–5.16 (m, 3 H, 3ϫ2Ј-
= 6.1 Hz, 3 H, 6III-H) ppm. 13C NMR (150 MHz, CDCl3): δ = H), 5.06 (d, J1,2 = 2.4 Hz, 1 H, 1II-H), 4.87 (br. s, 1 H, 1III-H), 4.73
205.95 (CH2CO), 174.13 (COOCH3), 171.19 (CH2COO), 170.48,
(d, J1,2 = 1.9 Hz, 1 H, 1I-H), 4.66–4.43 (m, 6 H, 3CH2Ph), 4.20–
4.03 (m, 11 H, 3ϫ4Јa,b-H, 4II-H, 4I-H, 2II-H, 4III-H, 2III-H in that
order), 3.93 (m, 1 H, 2I-H), 3.80–3.62 (m, 3III-H; 3.67, s, OCH3,
J2,3 = 2.8, J3,4 = 8.5 Hz, 3II-H; dd, 3.74, J2,3 = 3.1, J3,4 = 8.5 Hz,
169.40, 169.34, 169.26 (12 C, 4NHCO, 8CH3CO), 100.96 (JC,H
=
176.5 Hz, C-1III), 99.90 (br. s, JC,H = 173.1 Hz, C-1II), 98.73 (JC,H
= 167.3 Hz, C-1I), 98.48 (JC,H = 173.7 Hz, C-1IV), 75.03, 74.33 (C-
3I,II), 74.52 (C-2I), 74.11, 73.52 (C-3III,IV), 73.67 (C-2III), 73.10 (C- 3I-H; dd, 3.72, J2,3 = 3.0, J3,4 = 9.1 Hz, 10 H, 5III-H, 5II-H, 5I-H,
2II), 71.11 (C-2Ј), 71.06 (CH2Ph), 71.04, 71.02, 70.91 (3ϫC-2Ј),
1a"-H, in that order, incl. 3.76), 3.38, 3.36 (2t, J = 5.7 Hz, 1 H,
70.86, 70.47 (3 C, 3CH2Ph), 68.87, 67.85 (C-5II,III), 67.82 (C-5IV), 1b"-H), 2.45 (br. s, 1 H, 2III-OH), 2.33 (t, J = 7.2 Hz, 2 H, 5ЈЈ-H),
67.22 (C-2IV), 67.07 (C-1ЈЈ), 59.96, 59.91, 59.87 (4 C, 4ϫC-4Ј),
51.97, 51.82, 51.71, 51.59 (C-4I–IV), 51.52 (OCH3), 37.97 (CH2CO),
2.27–2.00 (m, 24 H, 3ϫ3Јa,b-H, incl. 6s, 2.14, 2.07, 2.05, 2.04,
2.02, 2.01, 6CH3CO), 1.71–1.54 (m, 4 H, 2ЈЈ-H, 4ЈЈ-H), 1.46–1.31
33.79 (C-5ЈЈ), 30.93, 30.88, 30.83 (4 C, 4ϫC-3Ј), 29.69 (CH3), 28.57 (m, 2 H, 3ЈЈ-H), 1.19 (d, partially overlapped, J5,6 = 6.3 Hz, 3 H,
(C-2ЈЈ), 28.10 (CH2COO), 25.59 (C-3ЈЈ), 24.27 (C-4ЈЈ), 20.82, 20.80, 6I-H), 1.18 (d, partially overlapped, J5,6 = 6.6 Hz, 6 H, 6II-H), 1.12
20.77, 20.75, 20.74, 20.69, 20.65 (8 C, 8CH3CO), 18.11, 18.07,
17.98, 17.86 (C-6I–IV) ppm. ESI-MS: m/z: 1951.8168 ([M + Na]+;
calcd. 1951.8155). C96H128N4O37 (1928.8): calcd. C 59.74, H 6.68,
N 2.90; found C 59.94, H 6.87, N 2.94.
(d, J5,6 = 6.2 Hz, 6 H, 6III-H) ppm. 13C NMR (150 MHz, CDCl3):
δ = 174.47 (COOCH3), 170.85, 170.83, 170.82 (3NHCO), 169.74,
169.72, 169.63, 169.62, 169.57 (6 C, 6CH3CO), 100.74 (C-1II), 99.80
(C-1III), 98.89 (C-1I), 75.57 (C-3III), 75.23 (C-3I), 74.23 (2 C, C-3II,
C-2I), 73.13 (C-2II), 71.16, (CH2Ph), 71.15, 70.02, 70.99 (3ϫC-2Ј),
70.84, 70.66 (2CH2Ph), 68.75 (C-5II), 68.14 (C-5III), 67.79 (C-5I),
67.06 (C-1ЈЈ), 66.64 (C-2III), 60.03, 59.89 (3 C, 3ϫC-4Ј), 52.05 (C-
4I), 51.71 (C-4II), 51.52 (OCH3), 51.22 (C-4III), 33.81 (C-5ЈЈ), 30.94,
30.92, 30.83 (3ϫC-3Ј), 28.57 (C-2ЈЈ), 25.57 (C-3ЈЈ), 24.27 (C-4ЈЈ),
20.86, 20.78, 20.76, 20.74, 20.64 (6 C, 6CH3CO), 18.19 (C-6II),
17.96 (C-6I), 17.74 (C-6III) ppm. ESI-MS: m/z: 1432.5818 ([M +
Na]+; calcd. 1432.6051).
1
Compound 27: H NMR (600 MHz, CDCl3): δ = 7.73 (br. s 1 H,
NHIV), 6.38 (d, JNH,4 = 9.4 Hz, 1 H, NHI), 6.30 (br. s 1 H, NHIII),
6.12 (d, JNH,4 = 9.7 Hz, 1 H, NHII), 5.49 (dd, J1,2 = 1.4, J2,3
=
3.0 Hz, 1 H, 2IV-H), 5.38 (br. s, 1 H, 1IV-H), 5.30–5.14 (m, 4 H,
4ϫ2Ј-H), 4.97 (d, J1,2 = 2.2 Hz, 1 H, 1II-H), 4.85–4.44 (m, 1I-H,
J1,2 = 1.7 Hz, 6 H, 5CHPh, incl. d, 4.76), 4.34–4.28 (m, 4 H,
2CHPh, incl. br. s, 4.34, 1III-H; br. s, 4.33, 2II-H), 4.24 (q, J =
10.1 Hz, 4IV-H), 4.20–3.97 (m, 4II-H, J = 9.9 Hz, 11 H, 5IV-H,
4ϫ4Јa-H, 3ϫ4Јb-H, 4I-H, 2III-H, 1a"-H, incl. br. s, 4.06, 2I-H; q,
3.99), 3.85 (dd, J2,3 = 3.2, J3,4 = 10.8 Hz, 1 H, 3IV-H), 3.82 (dd,
J2,3 = 2.7, J3,4 = 9.9 Hz, 1 H, 3I-H), 3.79–3.65 (m, 1 H, 3II-H; 3.69,
s, OCH3, J2,3 = 3.2, J3,4 = 10.8 Hz, 9 H, 4Јb-H, 3III-H, 5I–III-H,
incl. dd, 3.71), 3.59 (q, J = 9.7 Hz, 1 H, 4III-H), 3.41, 3.39 (2t, J =
5.6 Hz, 1 H, 1b"-H), 2.61–2.55 (m, 4 H, CH2CH2), 2.36 (t, J =
7.1 Hz, 2 H, 5ЈЈ-H), 2.35–1.82 (m, 35 H, 4ϫ3Јa,b-H, incl. 9s, 2.08,
2.07, 2.06, 2.04, 2.03, 2.01, 1.99, 1.96, 8CH3CO, CH3), 1.77–1.58
The foregoing trisaccharide 24 (110 mg, 0.08 mmol) was treated
with 5 following procedure A for glycosylation, and chromatog-
raphy (99:1Ǟ95:5 toluene/MeOH) gave compounds 25 (124 mg,
81%) and 27 (25 mg, 16%).
From Disaccharide 11 and Thioglycoside 8: The disaccharide ac-
ceptor 11 was treated with the donor 8 according to procedure B
(TLC 1:1 hexane/acetone). Chromatography with 4:1Ǟ3:2 hexane/
acetone gave a mixture 5:1 of compounds 25 and 27, which could
be resolved by chromatography with 98:2 toluene/MeOH, affording
amorphous 25 (1.49 g, 77%) and 27 (309 mg, 16%).
(m, 4 H, 2ЈЈ-H, 4ЈЈ-H), 1.55–1.36 (m, 2 H, 3ЈЈ-H), 1.26 (d, J5,6
=
6.2 Hz, 3 H, 6IV-H), 1.22 (d, J5,6 = 6.3 Hz, 3 H, 6I-H), 1.14 (d, J5,6
= 6.2 Hz, 3 H, 6II-H), 1.09 (d, J5,6 = 6.1 Hz, 3 H, 6I-H) ppm. 13C
NMR (150 MHz, CDCl3): δ = 206.36 (CH2CO), 174.35 (CO-
OCH3), 171.55 (CH2COO), 170.61, 170.51, 170.08, 170.00, 169.67,
169.54, 169.36, 169.31, 169.27 (12 C, 4NHCO, 8CH3CO), 99.80
(JC,H = 171.8 Hz, C-1II), 98.87 (JC,H = 169.6 Hz, C-1I), 97.51 (JC,H
5-(Methoxycarbonyl)pentyl 3-O-Benzyl-4-(2,4-di-O-acetyl-3-deoxy-
L
-glycero-tetronamido)-4,6-dideoxy-α-
bis[3-O-benzyl-4-(2,4-di-O-acetyl-3-deoxy-
4,6-dideoxy-α- -mannopyranosyl]-3-O-benzyl-4-(2,4-di-O-acetyl-3-
deoxy- -glycero-tetronamido)-4,6-dideoxy-α- -mannopyranoside
D
-mannopyranosyl-(1Ǟ2)-
L
-glycero-tetronamido)-
D
158.5 Hz, C-1III), 97.07 (JC,H = 174.9 Hz, C-1IV), 77.96 (C-3III),
=
L
D
76.26 (C-3I), 74.98 (C-3IV), 73.85 (br. s, C-3I), 73.30 (C-2I), 71.71
(CH2Ph), 71.24, 71.20 (2 ϫ C-2Ј), 71.06 (CH2Ph), 71.00, 70.57
(2ϫC-2Ј), 70.31 (C-2II), 69.96 (C-5III), 69.50 (CH2Ph), 69.10 (C-
5IV), 68.28 (C-2IV), 67.88 (C-5I), 67.71 (C-2III), 67.00 (C-1ЈЈ), 60.47,
59.93, 59.90, 59.68 (4ϫC-4Ј), 54.19 (C-4III), 52.32 (C-4II), 52.16
(C-4I), 51.61 (C-4IV), 51.55 (OCH3), 38.15 (CH2CO), 33.81 (C-5ЈЈ),
30.97, 30.79. 30.48 (4 C, 3ϫC-3Ј), 29.57 (CH3), 28.55 (C-2ЈЈ), 28.27
(CH2COO), 25.57 (C-3ЈЈ), 24.24 (C-4ЈЈ), 20.77, 20.73, 20.71, 20.66,
20.60 (8 C, 6CH3CO), 18.24 (C-6II), 18.00, 17.90 (C-6I,IV), 17.65
(C-6III) ppm. ESI-MS: m/z: 1967.7856 ([M + K]+; calcd.
1967.7895).
(26): When applied to compound 25 (1.49 g, 0.77 mmol), the gene-
ral procedure for cleavage of Lev group gave, after chromatography
(99.5:0.5 Ǟ 95:5 CH2Cl2/MeOH), product 26 in virtually theoreti-
cal yield as a foam (~1.40 g). [α]D = –27 (c = 0.2; CHCl3). 1H NMR
(600 MHz, CDCl3): δ = 6.20 (br. s, 1 H, NHI), 5.80 (br. s, 1 H,
NH), 5.21–5.15 (m, 4 H, 4ϫ2Ј-H), 5.05 (d, J1,2 = 2.5 Hz, 1 H, 1III
-
H), 4.99 (br. s, 1 H, 1II-H), 4.92 (br. s, 1 H, 1IV-H), 4.72 (d, J1,2
=
1.7 Hz, 1 H, 1I-H), 4.66–4.44 (m, 8 H, 4CH2Ph), 4.20–4.00 (m, 15
H, 4ϫ4Јa,b-H, 2II–IV-H, 4I–IV-H), 3.90 (br. s, 1 H, 2I-H), 3.80–3.72
(m, 3I,IV-H, J2,3 = 2.8, J3,4 = 9.4 Hz, 3II,III-H; dd, 3.74, J2,3 = 3.0,
J3,4 = 10.6 Hz, 5 H, 5I-H, incl. dd, 3.78), 3.71–3.61 (m, 7 H, 5II,IV
-
From Trisaccharide 23: Trisaccharide 23 (200 mg, 0.13 mmol) was
treated with NH2NH2·AcOH (14 mg, 0.16 mmol), as described in
the general procedure for removal of the Lev group. Chromatog-
raphy (99.5:0.5Ǟ97:3 CH2Cl2/MeOH), gave 5-(methoxycarbonyl)
pentyl 3-O-benzyl-4-(2,4-di-O-acetyl-3-deoxy--glycero-tetron-
amido)-4,6-dideoxy-2-O-levulinoyl-α--mannopyranosyl-(1Ǟ2)-3-
O-benzyl-4-(2,4-di-O-acetyl-3-deoxy--glycero-tetronamido)-4,6-di-
deoxy-α--mannopyranosyl-(1Ǟ2)-3-O-benzyl-4-(2,4-di-O-acetyl-
3-deoxy--glycero-tetronamido)-4,6-dideoxy-α--mannopyranoside
H, 1a"-H, incl. 3.67, s, OCH3), 3.37, 3.36 (2t, J = 5.8 Hz, 1 H, 1b"-
H), 2.45 (br. s, 1 H, 2IV-H), 2.34 (t, J = 7.1 Hz, 2 H, 5ЈЈ-H), 2.22–
2.00 (m, 35 H, 4ϫ3Јa,b-H, incl. 7s, 2.12, 2.09, 2.08, 2.05, 2.04,
2.03, 2.02, 2.01, 8CH3CO), 1.70–1.54 (m, 4 H, 2ЈЈ-H, 4ЈЈ-H), 1.46–
1.30 (m, 2 H, 3ЈЈ-H), 1.18 (d, J5,6 = 6.2 Hz, 3 H, 6I-H), 1.17 (d, J5,6
= 6.2 Hz, 3 H, 6II-H), 1.13 (d, partially overlapped, J5,6 = 6.2 Hz,
3 H, 6IV-H), 1.12 (d, partially overlapped, J5,6 = 6.2 Hz, 3 H, 6III
-
H) ppm. 13C NMR (150 MHz, CDCl3): δ = 174.43 (COOCH3),
170.75, 170.75 (4 C, 2NHCO), 169.71, 169.70, 169.59, 169.55 (8 C,
998
www.eurjoc.org
© 2007 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Org. Chem. 2007, 988–1000

Glycosylation under Thermodynamic Control
FULL PAPER
8CH3CO), 100.74 (C-1II), 99.95 (br. s, 2 C, C-1III,IV), 98.74 (C-1I), (150 MHz, CDCl3): δ = 174.50 (COOCH3), 170.80, 170.69, 170.68,
75.67, 75.11 (C-3I,IV), 75.59, 74.17 (br. s, 3 C, C-2I, C-3II,III), 73.06 170.67, 170.62, 170.59 (6NHCO), 169.93, 169.77, 169.69, 169.62,
(2 C, C-2II,III), 71.14, 71.10, 71.03, 71.00, 70.95, 70.83, 70.76 (8 C, 169.61, 169.51, 169.34, 169.18 (12 C, 12CH3CO), 100.54, 100.15,
4ϫC-2Ј, 4CH2Ph), 68.95, 68.87 (C-5II,III), 68.12 (C-5IV), 67.80 (C-
99.65 (3br. s, C-1II–IV), 98.88 (JC,H = 172.0 Hz, C-1I), 97.65 (JC,H
5I), 67.06 (C-1ЈЈ), 66.60 (C-2IV), 60.02, 59.96, 59.90, 59.89 (4 C, = 175.0 Hz, C-1VI), 97.53 (JC,H = 155.0 Hz, C-1V), 75.59, 76.79,
4ϫC-4Ј), 51.97 (C-4I), 51.66 (2 C, C-4II,IV), 51.52 (OCH3), 51.22 76.67, 76.33, 75.47, 74.25, 73.77, 73.10, 72.54 (12 C, C-2I–VI, C-
(C-4III), 37.97 (CH2CO), 33.79 (C-5ЈЈ), 30.93, 30.90. 30.81 (4 C, 3I–VI), 71.59, 71.33, 71.21, 71.11, 71.04, 70.95, 70.86, 70.65 (12 C,
4ϫC-3Ј), 28.55 (C-2ЈЈ), 25.57 (C-3ЈЈ), 24.25 (C-4ЈЈ), 20.82, 20.77, 6 ϫC-2Ј, 6CH2Ph), 69.58, 69.07, 68.93, 68.85, 67.99, 67.63 (C-
20.76, 20.75, 20.69, 20.63 (8 C, 8CH3CO), 18.09 (2 C, C-6II,III), 5I–VI), 66.89 (C-1ЈЈ), 60.48, 60.09, 59.89, 59.86, 59.77 (6 C, 6ϫC-
17.97 (C-6I), 17.76 (C-6IV) ppm. ESI-MS: m/z: 1853.7856 ([M +
Na]+; calcd. 1853.7787). C91H122N4O35 (1830.8): calcd. C 59.66, H
6.71, N 3.06; found C 59.45, H 6.87, N 3.07.
4Ј), 59.34 (OCH3-2VI), 53.37, 52.42, 52.18, 51.94, 51.70, 51.54
(6ϫC-4I–VI), 51.49 (COOCH3), 33.73 (C-5ЈЈ), 30.94, 30.87, 30.83,
30.78, 30.69, 30.54 (6ϫC-3Ј), 28.41 (C-2ЈЈ), 25.48 (C-3ЈЈ), 24.11
(C-4ЈЈ), 20.77, 20.74, 20.67, 20.65, 20.63, 20.58, 20.54, 20.50 (12 C,
12CH3CO), 18.20, 18.05, 17.94, 17.87, 17.57 (6 C, C-6I–VI) ppm.
5-(Methoxycarbonyl)pentyl 3-O-Benzyl-4-(2,4-di-O-acetyl-3-deoxy-
L
-glycero-tetronamido)-4,6-dideoxy-2-O-methyl-α-
osyl-(1Ǟ2)-tetrakis[3-O-benzyl-4-(2,4-di-O-acetyl-3-deoxy-
glycero-tetronamido)-4,6-dideoxy-α-
4-(2,4-di-O-acetyl-3-deoxy- -glycero-tetronamido)-4,6-dideoxy-α-
D-mannopyran-
5-(Methoxycarbonyl)pentyl 3-O-Benzyl-4-(3-deoxy-
amido)-4,6-dideoxy-2-O-methyl-α- -mannopyranosyl-(1Ǟ2)-
tetrakis[3-O-benzyl-4-(3-deoxy- -glycero-tetronamido)-4,6-dideoxy-
α- -mannopyranosyl]-3-O-benzyl-4-(3-deoxy- -glycero-tetron-
amido)-4,6-dideoxy-α- -mannopyranoside (31): 0.1  NaOMe was
L-glycero-tetron-
L
-
D
D
-mannopyranosyl]-3-O-benzyl-
L
L
D-
D
L
mannopyranoside (28): Tetrasaccharide acceptor 26 (1.75 g,
0.96 mmol) was treated with donor 18 (1.15 g, 1.25 mmol) (Pro-
cedure B, Table 1) to give (1:1 hexane:acetone and 4:1Ǟ1:1 hex-
ane/acetone, for analytical and preparative chromatography, respec-
tively), a 5:1 mixture (NMR) of compounds 28 and 29, which could
be further resolved by chromatography (99:1 Ǟ 95:5 toluene/
MeOH).
D
added to a solution of the hexasaccharide 28 (1.1 g, 0.41 mmol) in
MeOH (200 mL) until the pH was strongly alkaline to litmus. The
mixture was kept overnight at room temperature, when TLC
(4:1:0.1 CH2Cl2/MeOH-AcOH) showed that the reaction was com-
plete. After neutralization (Amberlite IR-120, H+-resin),
chromatography (85:15 CH2Cl2/MeOH), gave the deacetylated
Compound 28: (1.60 mg, 62%), [α]D = –10 (c = 1.1; CHCl3). 1H
NMR (600 MHz, CDCl3): δ = 6.21–5.86 (m, 5 H, NH), 5.22–5.15
(m, 6 H, 6ϫ2Ј-H), 5.04–4.98 (m, 4 H, H-1II–V), 4.89 (br. s, 1 H,
1VI-H), 4.69 (br. s, 1 H, 1I-H), 4.66–4.43 (m, 12 H, 6CH2Ph), 4.21–
4.03 (m, 34 H, 6ϫ4Јa,b-H, 2II–V-H, 4I–VI-H), 3.87 (br. s, 1 H, 2I-
H), 3.81–3.61 (m, 17 H, 2VI-H, 3I–VI-H, 5I–VI-H, 1a"-H, incl. 3.67,
s, COOCH3), 3.36, 3.35 (2t, J = 5.5 Hz, 1 H, 1b"-H), 3.24 (br. s, 3
H, 2VI-OMe), 2.32 (t, J = 7.1 Hz, 2 H, 5ЈЈ-H), 2.24–1.99 (m, 42 H,
6ϫ3Јa,b-H, incl. 9s, 2.17, 2.11, 2.06, 2.05, 2.04, 2.03, 2.02, 2.01,
2.00, 12CH3CO), 1.69–1.53 (m, 4 H, 2ЈЈ-H, 4ЈЈ-H), 1.45–1.29 (m, 2
H, 3ЈЈ-H), 1.17–1.08 (m, 18 H, 6I–VI-H) ppm. 13C NMR (150 MHz,
CDCl3): δ = 174.53 (COOCH3), 170.90, 170.82, 170.80 (6 C,
6NHCO), 169.73, 169.72, 169.71, 169.66, 169.60, 169.51, 169.36
(12 C, 12CH3CO), 100.50 (2 C), 100.00, 99.79 (3 br. s, JC,H = 171.3,
169.0, 169.0 Hz, C-1II–V), 99.06 (br. s, JC,H = 172.1 Hz, C-1VI),
98.67 (JC,H = 170.4 Hz, C-1I), 75.43, 75.31, 75.15, 74.80, 74.44,
74.06, 73.83, 73.69 (C-2I,VI, C-3I–VI), 73.25 (br. s, 4 C, C-2II–V),
71.25, 71.20, 71.14, 71.12, 71.07, 71.05, 71.02, 71.00, 70.98, 70.68,
70.48, 70.44 (6ϫC-2Ј, 6CH2Ph), 69.18, 69.00, 68.93, 68.89, 68.76,
67.59 (C-5I–VI), 67.09 (C-1ЈЈ), 60.07, 59.99, 59.96, 59.93 (6 C, 6ϫC-
4Ј), 59.03 (OCH3-2VI), 51.86, 51.80, 51.75, 51.63 (6 C, 6ϫC-4I–VI),
51.58 (COOCH3), 33.82 (C-5ЈЈ), 30.95, 30.94, 30.87 (6 C, 6ϫC-3Ј),
28.56 (C-2ЈЈ), 25.62 (C-3ЈЈ), 24.26 (C-4ЈЈ), 20.84, 20.83, 20.75,
1
compound 30 (705 mg, 80%). H NMR (300 MHz, CD3OD): δ =
5.11–5.03 (4d, J1,2 = 1.5, 1.5, 1.5, 2.1 Hz, 4 H, H-1II–V), 4.87 (d,
J1,2 = 1.8 Hz, 1 H, 1VI-H), 4.77 (d, J1,2 = 1.4 Hz, 1 H, 1I-H), 4.54–
4.68 (m, 12 H, 6CH2Ph), 4.24–4.04 (m, 24 H, 6ϫ2Ј-H, 2II–V-H,
4I–VI-H), 4.02–3.64 (m, 30 H, 1a"-H, 2I,VI-H, 3I–VI-H, 6ϫ4Јa,b-H,
5I–VI-H, incl. 3.65, s, COOCH3), 3.40, 3.38 (2t, J = 5.5 Hz, 1 H,
1b"-H), 3.15 (br. s, 3 H, 2VI-OMe), 2.33 (t, J = 7.2 Hz, 2 H, 5ЈЈ-
H), 2.10–1.95 (m, 6 H, 6ϫ3Јa-H), 1.82–1.52 (m, 10 H, 6ϫ3Јb-H,
4ЈЈ-H, 2ЈЈ-H, in that order), 1.45–1.36 (m, 2 H, 3ЈЈ-H), 1.20–1.01
(m, 18 H, 6I–VI-H) ppm. 13C NMR (75 MHz, CD3OD): δ = 177.88,
177.83, 177.80, 177.63 (6 C, 6 ϫ NHCO), 176.05 (COOCH3),
102.42, 102.27, 102.19 (4 C, C-1II–V), 100.47 (C-1VI), 100.40 (C-1I),
77.51, 77.11, 76.88, 76.20, 76.06, 75.82, 75.80 (12 C, C-2I–VI, C-
3I–VI), 73.25, 72.98, 72.88, 72.81, 72.50 (6ϫCH2Ph), 70.88 (6 C,
6ϫC-2Ј), 70.05, 70.04, 70.03, 69.87, 69.31 (6 C, C-5I–VI), 68.60 (C-
1ЈЈ), 59.94 (6 C, 6ϫC-4Ј), 59.10 (OCH3-2VI), 53.49, 53.29, 53.01 (6
C, 6 ϫC-4I–VI), 52.26 (COOCH3), 33.60 (C-5ЈЈ), 34.78 (6 C, 6ϫC-
3Ј), 30.11 (C-2ЈЈ), 26.91 (C-3ЈЈ), 25.74 (C-4ЈЈ), 18.74, 18.63, 18.60,
18.50 (6 C, C-6I–VI) ppm. ESI-MS: m/z: 2230.0064 ([M + 1 +
2 Na]3+; calcd. 2230.0125); 2229.0034 ([M + 2 Na]2+; calcd.
2229.0047).
A mixture of the foregoing compound 30 (640 mg, 0.29 mmol) and
5% Pd-C (600 mg) in MeOH (50 mL) was stirred under hydrogen
pressure (100 psi) for 4 h, when TLC (1:1:0.1 CHCl3/MeOH-
AcOH) showed that the debenzylation was complete and that one
product was formed. After filtration through a celite pad, the fil-
trate was concentrated chromatographed (3:2:0.1 CHCl3/MeOH/
20.73, 20.67 (12 C, 12CH3CO), 18.80, 18.05, 18.03 (6 C, C-6I–VI
)
ppm. ESI-MS: m/z: 2732.5002 ([M –1 + 2 Na]+; calcd. 2732.1237).
C134H178N6O51 (2688.9): calcd. C 59.86, H 6.67, N 3.13; found C
59.73, H 6.76, N 3.13.
Compound 29: (350 mg, 13%). 1H NMR (600 MHz, CDCl3): δ = AcOH) and a solution of the product was freeze-dried to give pure
6.40–5.92 (m, 4 H, NH), 5.30–5.11 (m, 7 H, 6ϫ2Ј-H, incl. 5.27, 31 (430 mg, 90%) as a white amorphous solid, which was identical
br. s, 1VI-H), 5.11, 5.02, 5.00 (3s, 3 H, H-1II–IV), 4.82–4.38 (m, 1- with the previously, independently synthesized substance.[18] 1
H
HI, J1,2 = 1.4 Hz, 12 H, 11CHPh, incl. 4.75, d), 4.37–3.93 (m, 24 NMR (600 MHz, D2O): δ = 5.21 (d, J1,2 = 1.8 Hz, 1 H, 1VI-H),
H, CHPh, 6ϫ4Јa,b-H, 4I–VI-H, 2I–IV-H, 5V-H, incl. s, 4.29, 1V-H), 5.19, 5.17, 5.16, 5.15 (4d, J1,2 = 1.6, 1.5, 1.5, 1.3 Hz, 4 H, H-1II–V),
3.86–3.65 (m, 17 H, 2V,VI-H, 3I–VI-H, 5I–IV,VI-H, 1a"-H, incl. 3.67, 4.89 (d, J1,2 = 1.6 Hz, 1 H, 1I-H), 4.31–4.27 (m, 6 H, 6ϫ2Ј-H),
s, OCH3), 3.40, 3.38 (2t, J = 5.5 Hz, 1 H, 1b"-H), 3.26 (br. s, 3 H,
2VI-OMe), 2.34 (t, J = 7.1 Hz, 2 H, 5ЈЈ-H), 2.24–1.83 (m, 42 H,
6ϫ3Јa,b-H, incl. 11s, 2.15, 2.08, 2.05, 2.03, 2.01, 2.00, 1.99, 1.98,
4.19–3.86 (m, 4I-H, J2,3 = 3.3, J3,4 = 10.6 Hz, 3VI-H; dd, 4.05, J2,3
= 3.2, J3,4 = 10.3 Hz, 3I-H; t, 3.92, J = 10.3 Hz, 18 H, 2I–V-H, 3II–V
H, 5I–VI-H, incl. dd, 4.07), 3.83 (t, J = 10.4 Hz, 4VI-H), 3.77 (dd, 1
-
1.97, 1.96, 1.95, 12CH3CO), 1.66–1.53 (m, 4 H, 2ЈЈ-H, 4ЈЈ-H), 1.47– H, 2VI-H), 3.78–3.76 (m, 12 H, 6ϫ4Јa,b-H), 3.72, 3.70 (2t, J =
1.26 (m, 2 H, 3ЈЈ-H), 1.23–1.08 (m, 18 H, 6I–VI-H) ppm. 13C NMR
6.1 Hz, 1 H, 1a"-H), 3.68 (s, 3 H, COOCH3), 3.55, 3.53 (2t, J =
Eur. J. Org. Chem. 2007, 988–1000
© 2007 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
999

R. Adamo, P. Kovácˇ
FULL PAPER
6.1 Hz, 1 H, 1b"-H), 3.49 (s, 3 H, 2VI-OMe), 2.40 (t, J = 7.4 Hz, 2
H, 5ЈЈ-H), 2.07–2.00 (m, 6 H, 6 ϫ 3Јa-H), 1.88–1.81 (m, 6 H,
6ϫ3Јb-H), 1.65–1.59 (m, 4 H, 4ЈЈ-H, 2ЈЈ-H), 1.42–1.39 (m, 2 H,
3ЈЈ-H), 1.20–1.17 (m, 15 H, 6I–V-H), 1.14 (d, J5,6 = 6.2 Hz, 3 H,
6VI-H) ppm. 13C NMR (150 MHz, D2O): δ = 183.42 (COOCH3),
180.32, 180.18, 180.17, 180.16, 180.01 (6 C, 6NHCO), 103.57,
103.48, 103.46, 103.42 (C-1II–V), 100.67 (C-1VI), 100.14 (C-1I),
81.65 (C-2VI), 80.47 (C-2I), 80.27, 79.97, 79.94, 79.88 (C-2II–V),
71.70 (6 C, 6ϫC-2Ј), 71.01, 70.99, 70.73, 70.56, 70.41, 70.32, 70.21,
70.17, 70.13 (12 C, C-3I–VI, C-5I–VI), 70.64 (C-1ЈЈ), 61.48 (OCH3-
2VI), 60.57 (6 C, 6ϫC-4Ј), 55.87, 55.81, 55.69, 55.64 (6 C, 6ϫC-
4I–VI), 54.86 (COOCH3), 38.72, 38.70, 38.66 (6 C, 6ϫC-3Ј), 36.33
(C-5ЈЈ), 30.80 (C-2ЈЈ), 27.59 (C-3ЈЈ), 26.72 (C-4ЈЈ), 19.63, 19.59,
19.58, 19.53, 19.52 (6 C, C-6I–VI) ppm. ESI-MS: m/z: 1665.7369
([M + Na]+; calcd. 1665.7426).
[12] R. Adamo, P. Kovácˇ, Eur. J. Org. Chem. 2006, 2803–2809.
[13] A. Arencibia-Mohar, A. Ariosa-Alvarez, O. Madrazo-Alonso,
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[14] J. H. van Boom, P. M. J. Burgers, Tetrahedron Lett. 1976, 17,
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Acknowledgments
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Received: September 28, 2006
Published Online: December 21, 2006
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