Acetolysis of 6-deoxysugar disaccharide building blocks: Exo versus endo activation

Article abstract of DOI:10.1002/ejoc.200800696

Two different protocols for the mild and selective acetolysis of 6-deoxysugar methyl disaccharides under thermodynamic or kinetic control have been developed. The structures of the disaccharides obtained depend on the protocol used and, in the kinetically

Full text of DOI:10.1002/ejoc.200800696

FULL PAPER
DOI: 10.1002/ejoc.200800696
Acetolysis of 6-Deoxysugar Disaccharide Building Blocks: exo versus endo
Activation
Luigi Cirillo,[a] Emiliano Bedini,*[a] and Michelangelo Parrilli[a]
Keywords: Acetolysis / Deoxysugars / Oligosaccharides / Hexofuranoses / Zinc
Two different protocols for the mild and selective acetolysis
of 6-deoxysugar methyl disaccharides under thermodynamic
or kinetic control have been developed. The structures of the
disaccharides obtained depend on the protocol used and, in
the kinetically controlled cases, on the 6-deoxysugar config-
uration and protecting group pattern too. The behavior of 6-
deoxyhexose oligosaccharides of different series (rhamno,
quinovo, and fuco) under these two reaction conditions has
been studied and rationalized based on the competition be-
tween exo versus endo oxygen activation in the acetolysis
mechanism.
(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim,
Germany, 2008)
deed, the acetolysis of common hexose glycosides has been
reported to produce high yields of the latter products by
kinetic control in very few cases.[2d,2e,3,4] To the best of our
knowledge, only one example of prevalent endo activation
has been reported for the acetolysis of 6-deoxyhexose glycos-
ides: a 6-deoxy--Tal-(1Ǟ2)--Rha-OtBu building block
afforded mainly an E-like disaccharide.[5]
Introduction
Acetolysis of carbohydrates is a widely used reaction that
involves the cleavage of the glycosidic bond and the simulta-
neous acetylation of the hydroxy groups thus formed and/
or present before the solvolysis. Acetolysis finds extensive
application as a selective degradation method in the struc-
tural elucidation of polysaccharides.[1] Similarly, the conver-
sion of alkyl and aryl glycosides of mono- and oligosaccha-
rides into 1-O-acetylated species is a key reaction in oligo-
saccharide synthesis because the products can be easily con-
verted into both glycosyl donors and glycosyl acceptors.
Owing to the importance of such reactions, several stud-
ies of the mechanism of monosaccharide acetolysis have ap-
peared in literature.[2] The mechanism can be summarized
as shown in Scheme 1. Briefly, the acetylium ion, formed
from Ac2O under acid conditions, can activate the endo-
cyclic as well as the exocyclic oxygen towards glycoside
cleavage. Activation of the exo site provides 1-O-Ac-py-
ranoside products B after acetic acid attack on the oxocarb-
enium ion, whereas endo activation affords open-chain
products C, which can react further under acid conditions.
Indeed, they can be activated by a second acetylium ion to
afford 1,1-diacetate D and/or 1-O-Ac-furanoside derivatives
E. It has been shown that endo activation proceeds more
rapidly, even if the relative rates of the two activation
mechanisms are rather dependent on the sugar configura-
tion.[2h] Nevertheless, acetolysis is usually governed not by
kinetic, but by thermodynamic conditions, thus giving
products B in much higher yields than C, D, and/or E. In-
Deoxyhexoses, and above all 6-deoxyhexoses, are fre-
quently found in several natural sources: they have been
found as constituents of O-antigen lipopolysaccharides[6]
and also as components of glycoproteins, glycolipids, and
other glycoconjugates such as cardioglycosides, natural an-
tibiotics, and anticancer agents.[7] Because the biological
role of the deoxyhexose components is very often crucial
within these natural molecules, the synthesis of deoxy-
hexose-containing targets has been widely investigated. To
the best of our knowledge, no comprehensive studies on the
acetolysis of 6-deoxyhexose glycosides exist in the literature.
Very recently we reported a mild, selective acetolysis of 6-
deoxysugar oligosaccharide building blocks governed by
the armed–disarmed effect: by using suitable protecting
group patterns on the oligosaccharides we were able to con-
vert the methyl glycosides into 1-O-Ac-pyranoside deriva-
tives (B-like products) without cleaving the interglycosidic
bonds.[8] In this work we have investigated the possibility of
obtaining kinetically controlled C-, D-, and E-like disaccha-
ride products. In fact, acetolysis of 6-deoxyhexoses under
kinetic control should be more easily achieved with respect
to common non-deoxyhexoses because the lack of the elec-
tron-withdrawing oxygen atom at the 6-position enhances
the nucleophilicity of the endocyclic oxygen, thus favoring
further the kinetically controlled endo activation pathway.
A method in which one 6-deoxypyranose ring is selectively
converted into a furanose cycle (kinetically controlled prod-
uct E) at the disaccharide level could be very attractive for
[a] Dipartimento di Chimica Organica e Biochimica, Università di
Napoli “Federico II”, Complesso Universitario Monte Santan-
gelo,
Via Cintia 4, 80126 Napoli, Italy
Fax: +39-081-674393
E-mail: ebedini@unina.it
5704
© 2008 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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Acetolysis of 6-Deoxysugar Disaccharide Building Blocks
Scheme 1. endo versus exo activation mechanism for the acetolysis reaction.
the synthesis of glycofuranose-containing oligosaccharides.
The next step of the work was the screening of the ace-
These molecules have been the targets of much synthetic tolysis conditions that would allow a kinetically controlled
effort over the last 10 years[9] as they are present in some endo activation mechanism and at the same time be mild
pathogenic microorganisms, such as the Mycobacteria,[10] enough to allow the armed–disarmed effect in order to ob-
Trypanosoma, and Leishmania[11] species. Therefore, the tain selectively 1-O-Ac-furanoside disaccharide products.
synthesis of 6-deoxyglycofuranose-containing structures First, model compound 17 was treated with 10:10:1 (v/v/v)
could afford useful analogues and aid the understanding of Ac2O/AcOH/TFA.[19] By conducting the reaction at
the biosynthesis and the role of glycofuranose in microorga- 70 °C,[8] 1-O-Ac-pyranoside derivative 23 was obtained in
nisms as well as the design of novel drugs for the treatment 95% yield, as expected through a thermodynamically con-
of diseases caused by such pathogenic species.
trolled exo activation mechanism (Table 1, entry 1). By low-
ering the reaction temperature to 5 °C, no reaction was ob-
served and the starting compound was recovered quantita-
tively even after 8 d (entry 2). Replacement of TFA with a
stronger acid such as H2SO4 (100:1 Ac2O/H2SO4 at 0 °C)
led very rapidly, even at low temperatures, to an uncontrol-
lable reaction, which produced a very complex mixture with
derivative 24 as the main product (25% yield; entry 3). Fi-
nally, a slight modification[20] of the known procedure using
freshly fused ZnCl2 in 2:1 (v/v) Ac2O/AcOH[21] (10 instead
of 20 equiv. of ZnCl2, 5 °C instead of room temp.; entry 4)
afforded the desired 1-O-Ac-furanoside derivative 25 in
good yield (76%) together with a small quantity of 1-O-Ac-
pyranoside 23 (16%). The identity of 25 was confirmed by
Results and Discussion
The first step of the work was the synthesis of a set of 6-
deoxysugar disaccharide methyl glycosides. This was ac-
complished by the standard glycosylation reaction of -
rhamnose thioglycoside 1[12] with the known glycosyl ac-
ceptors 2,[13] 3,[14] 4,[14] 5,[15] 6,[15] and the novel acceptor 8
(obtained by phase-transfer benzylation of diol 7)[16] as well
as the reaction of -fucose thioglycoside 9[12] with glycosyl
acceptor 10[17] (Scheme 2). Glycosylations under the NIS/
TfOH protocol proceeded in moderate to excellent yields to
give the disaccharide methyl glycosides 11–17. De-O-al-
lylation of 16 with PdCl2 and subsequent acetylation of the
resulting alcohol afforded disaccharide 18. Disaccharides 21
and 22 were obtained by de-O-benzenesulfonylation of
19[18] with sodium amide and subsequent acetylation or
benzoylation of the resulting alcohol 20. Note that all the
disaccharides were synthesized with a disarming ester pro-
tecting group at the 2-position of the non-pseudo-reducing
unit in order to avoid the acetolytic cleavage of the glyco-
sidic linkage.[8]
1
MALDI-TOF MS and NMR spectroscopy. The JH,H val-
ues (J1,2 = 0.8 Hz, J2,3 = 5.4 Hz, J3,4 = 3.2 Hz, J4,5
=
9.8 Hz) of the 1-O-acetylated residue were typical of a
manno-configured furanose cycle[22] and the resonance at δ
= 5.01 ppm for 5A-H confirmed the acetylation of its gemi-
nal hydroxy group.
The synthesized disaccharides 11–16, 18, 21, and 22 were
subjected to acetolysis by the ZnCl2 protocol described
above as well as with the 10:10:1 (v/v/v) Ac2O/AcOH/TFA
procedure at 70 °C. The results are summarized in Table 2.
As expected,[8] the latter protocol allowed in all cases the
Eur. J. Org. Chem. 2008, 5704–5714
© 2008 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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L. Cirillo, E. Bedini, M. Parrilli
FULL PAPER
Table 1. Screening of acetolysis conditions on model compound 17.
[a] Reaction conditions: A: 10:10:1 (v/v/v) Ac2O/AcOH/TFA,
70 °C; B: 10:10:1 (v/v/v) Ac2O/AcOH/TFA, 5 °C; C: 100:1 (v/v)
Ac2O/H2SO4, 0 °C; D: ZnCl2 (10 equiv.), 2:1 (v/v) Ac2O/AcOH,
5 °C. [b] Isolated yield.
afforded 1-O-Ac-pyranoside disaccharide derivatives in
good to excellent yields regardless of the 6-deoxyhexose
configuration (entries 1B–9B). In the same manner, acetoly-
sis conducted by the ZnCl2 protocol selectively involved the
armed monose unit, but the products obtained depended
strictly on the configuration of the 6-deoxyhexose sugar. In
fact, with rhamno-configured units, acetolysis with ZnCl2
always afforded the products under kinetic control: com-
pounds 11, 21, and 22 were transformed into 1-O-Ac-fu-
ranoside disaccharide derivatives (E-like products) in good
yields (entries 1A–3A), whereas compounds 16 and 18 gave
predominantly the open-chain 1-O-acetyl-1-O-methyl ace-
tals (C-like products) 32 and 34, respectively (entries 4A
and 5A). 1-O-Ac-pyranoside derivatives were isolated in re-
actions 1A–5A as minor products (15–25% yields). In the
case of substrate 18, the formation of the C-like derivative
34 could be supposedly due to the lower electron-donating
effect of the acetyl-protecting group at the 4A-O position of
16 as compared with the benzyl group at the same position
in compounds 11, 21, and 22. This avoids the conversion of
C- into E-like products, whereas this transformation is
rather easier in the presence of a benzyl group at the 4A-O
position. The preference for compound 16 to afford the C-
like derivative 32 cannot be easily rationalized and therefore
will be the object of future more detailed investigations.
In contrast to the rhamnose-rhamnose species, the ace-
tolysis by ZnCl2 of rhamnose-fucose methyl disaccharides
14 and 15 seems to proceed through an exo activation
Scheme 2. Synthesis of a set of 6-deoxysugar disaccharide methyl
glycosides. Reagents and conditions: (a) NIS, TfOH, AW-300 MS
(4 Å), CH2Cl2, –20 °C, 11: 49%; 12: 83%; 13: 82%; 14: 87%; 15:
88%; 16: 40%; 17: 94%; (b) BnBr, KOH, TBAI, toluene, room
temp., 72%; (c) i. PdCl2, 1:1 (v/v) CH2Cl2/MeOH, room temp.; ii.
Ac2O, py, room temp., 75% (after two steps); (d) NaNH2, DMF,
70 °C, 64%; (e) Ac2O, py, room temp., 99%; (f) BzCl, py, room
temp., 83%.
selective acetolysis of the glycosidic bond involving the mechanism giving the thermodynamically controlled 1-O-
monose unit protected with an arming benzyl group at the Ac-pyranoside derivative 35 (entries 6A and 7A). The for-
2-O position through an exo activation mechanism: This mation of traces of 1-O-Ac-furanosides could be detected
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Eur. J. Org. Chem. 2008, 5704–5714

Acetolysis of 6-Deoxysugar Disaccharide Building Blocks
Table 2. Acetolysis of 6-deoxysugar disaccharide methyl glycosides.
1
[a] Isolated yield. [b] Anomeric ratio measured by H NMR spectroscopy. [c] Anomeric ratio measured by isolation of the two anomers.
Eur. J. Org. Chem. 2008, 5704–5714
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L. Cirillo, E. Bedini, M. Parrilli
FULL PAPER
by MALDI-TOF MS analysis of the crude reaction mix- pseudo-reducing unit in the furanose form and/or open-
tures, but such compounds were not isolable by chromatog- chain acyl acetals) with suitably protected rhamno and β-
raphy due to their very low yield. The behavior of rham- quinovo species. Further studies on the competition between
nose-quinovose species 12 and 13 was strictly dependent on the exo and endo activation mechanisms in the acetolysis of
the configuration of the methyl aglycon: α-configured disac- oligosaccharides as well as the application of these findings
charide 12 was acetolyzed by an exo activation mechanism, to the synthesis of biologically relevant oligosaccharides
which furnished 1-O-Ac-pyranoside derivative 36 in almost containing 6-deoxyhexose moieties are currently underway.
quantitative yield (entry 8A), whereas β-derivative 13 gave
open-chain derivative 37 and E-like derivative 38 in a 1:1
molar ratio (entry 9A). Interestingly, the low tendency of
the fuco-configured moiety to undergo endo activation by
the ZnCl2 protocol fits well with the kinetic data reported
for the acetolysis of sugars in the galacto, gluco, and manno
series. First-order rate constants for exo activation of
galacto-configured sugars are higher than for gluco-config-
Experimental Section
General Methods: 1H and 13C NMR spectra were recorded with
Varian XL-200 (1H: 200 MHz; 13C: 50 MHz), Varian Gemini-300
(1H: 300 MHz; 13C: 75 MHz), Bruker DRX-400 (1H: 400 MHz;
13C: 100 MHz), or Varian INOVA 500 (1H: 500 MHz; 13C:
1
125 MHz) instruments in CDCl3 (CHCl3 as internal standard: H:
ured substrates.[2g] In addition, the first-order rate constant
measured for endo activation of a manno-configured sub-
strate is higher than for the gluco series.[2h] This can be sum-
marized with a relative order for the tendency to give an
acetolysis reaction through an endo anomeric kinetically
controlled mechanism, that is: manno Ͼ gluco Ͼ galacto,
whereas the exo anomeric activation follows a different or-
der (galacto Ͼ manno Ͼ gluco), which has recently been
demonstrated to be mainly dictated by the less electron-
withdrawing power of axial over equatorial oxygens.[23]
Therefore, when subjected to the ZnCl2 protocol, rhamno-
configured substrates 11, 16–18, 21, and 22 gave predomi-
nantly kinetically controlled products, fuco-configured de-
rivatives 14 and 15 preferred an exo activation mechanism
even under ZnCl2 conditions, whereas the results of the re-
actions of the two substrates of the quinovo series, 12 and
13, were highly dependent on the anomeric configuration.
The major tendency for the β-quinovose to give kinetically
controlled products with respect to the α moiety can be as-
cribed, in general, to the greater nucleophilicity of the endo-
cyclic oxygen in the β anomer. In fact, in contrast with the
α anomer, the endocyclic oxygen is not involved in nσ* do-
nation to the C1–O bond in the β anomer, whereas the exo-
cyclic oxygen is involved in the exo anomeric effect in both
anomers.[2e] Anyway, a precise and detailed understanding
of the effect of the 6-deoxysugar configuration on the ace-
tolysis reaction with ZnCl2 will surely also require a future
analysis of how ZnII–sugar coordination influences the nu-
cleophilicity of the exo and endo anomeric oxygen atoms.
CHCl3 at δ = 7.26 ppm; 13C: CDCl3 at δ = 77.0 ppm). Assignment
of the proton chemical shifts was based on 1D HOHAHA experi-
ments. Positive MALDI-TOF MS spectra were recorded with an
Applied Biosystem Voyager DE-PRO MALDI-TOF mass spec-
trometer in the positive mode: compounds were dissolved in
CH3CN at a concentration of 1 mg/mL and one microliter of these
solutions was mixed with one microliter of a 20 mg/mL solution of
2,5-dihydroxybenzoic acid in 7:3 CH3CN/water. Optical rotations
were measured with a JASCO P-1010 polarimeter. Analytical thin-
layer chromatography (TLC) was performed on aluminium plates
precoated with Merck Silica Gel 60 F254 as the adsorbent. The
plates were developed with a 10% H2SO4 ethanolic solution and
by heating to 130 °C. Column chromatography was performed on
Merck Kieselgel 60 (63–200 mesh).
Methyl 4-O-Allyl-2-O-benzyl-α-L-rhamnopyranoside (8): Diol 7
(301 mg, 1.38 mmol) was dissolved in toluene (15 mL) and treated
with TBAI (476 mg, 1.28 mmol), BnBr (328 µL, 2.75 mmol), and
then KOH (690 mg, 10.8 mmol). The mixture was stirred at room
temp. for 30 min and then treated with 1:1 AcOEt/water (25 mL)
and stirred overnight. After that the organic layer was collected,
dried with anhydrous Na2SO4, filtered, and concentrated. The resi-
due was subjected to column chromatography (7 to 10% ethyl ace-
tate in petroleum ether) to afford 8 (310 mg, 72%) as a yellowish
1
oil. [α]D = –9 (c = 0.8, CH2Cl2). H NMR (200 MHz, CDCl3): δ =
7.34 (m, 5 H, Ar-H), 5.93 (m, 1 H, OCH2CH=CH2), 5.26 (dq, Jvic
= 17.4, Jgem = Jlong-range = 1.4 Hz, 1 H, trans OCH2CH=CHH),
5.13 (d, Jvic = 10.2, Jgem = Jlong-range = 1.4 Hz, 1 H, cis
OCH2CH=CHH), 4.73 (dt, Jgem = 11.6 Hz, 1 H, OCHHPh), 4.68
(d, J1,2 = 1.4 Hz, 1 H, 1-H), 4.58 (d, Jgem = 11.6 Hz, 1 H,
OCHHPh), 4.33 (ddt, Jgem = 12.4, Jvic = 5.6, Jlong-range = 1.4 Hz, 1
H, OCHHCH=CH2), 4.13 (ddt, Jgem = 12.4, Jvic = 5.6, Jlong-range
1.4 Hz, 1 H, OCHHCH=CH2), 3.83 (br. m, 1 H, 3-H), 3.69 (dd,
J2,3 = 3.6, J2,1 = 1.6 Hz, 1 H, 2-H), 3.59 (dq, J5,4 = 9.2, J5,6
=
=
6.2 Hz, 1 H, 5-H), 3.31 (s, 3 H, OCH3), 3.18 (t, J4,3 = J4,5 = 9.2 Hz,
1 H, 4-H), 1.31 (d, J6,5 = 6.2 Hz, 3 H, 6-H) ppm. 13C NMR
(CDCl3, 50 MHz): δ = 137.7 (Cipso-Bn), 135.0 (OCH2CH=CH2),
128.5–127.8 (C-Ar), 116.8 (OCH2CH=CH2), 98.0 (C-1) 81.9, 78.5,
73.8, 73.0, 71.4, 67.0 (C-2, C-3, C-4, C-5, OCH2Ph,
OCH2CH=CH2), 54.6 (OCH3), 18.0 (C-6) ppm. MS (MALDI-
TOF): calcd. for C17H24O5 [M]+ 308.16; found 330.99 [M + Na]+.
C17H24O5 (308.37): calcd. C 66.21, H 7.84; found C 66.00, H 7.70.
Conclusions
A mild and selective acetolysis of 6-deoxysugar methyl
disaccharides based on the armed–disarmed concept can be
accomplished by two different protocols. The first one
[10:10:1 (v/v/v) Ac2O/AcOH/TFA at 70 °C] affords 1-O-
acetylated disaccharides in the pyranose form as the prod-
ucts of a thermodynamically controlled mechanism with ac-
tivation at the exo anomeric oxygen, whatever the configu-
ration of the sugar,[8] whereas the second one [10 equiv. of
ZnCl2 in 2:1 (v/v) AcO/AcOH at 5 °C] affords kinetically
Typical Glycosylation Procedure:
A mixture of the acceptor
(173 µmol) and thioglycoside donor (222 µmol) was co-evaporated
three times with toluene (2 mL). The residue was dried, mixed with
NIS (282 µmol), and freshly activated with AW-300 molecular si-
controlled products (1-O-acetyl disaccharides with the eves (4 Å) under Ar, cooled to –20 °C, and suspended in CH2Cl2
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Acetolysis of 6-Deoxysugar Disaccharide Building Blocks
(3.0 mL). A 0.57  solution of TfOH in CH2Cl2 (100 µL, 57 µmol)
was added. After 1 h stirring at –20 °C, the mixture was diluted
with CH2Cl2 and washed with 1:1 (v/v) 1  NaHCO3/10%
Na2S2O3. The organic layer was collected, dried with anhydrous
Na2SO4, filtered, concentrated, and purified by chromatography
(ethyl acetate in toluene).
(3 CH3CO), 17.8, 16.9 (C-6A, C-6B) ppm. MS (MALDI-TOF):
calcd. for C33H42O12 [M]+ 630.27; found 652.89 [M + Na]+.
C33H42O12 (630.68): calcd. C 62.85, H 6.71; found C 62.70, H 6.67.
Methyl
benzyl-α-
2,3,4-Tri-O-acetyl-α-
D-fucopyranoside (14): [α]D = –71.0 (c = 2.1, CH2Cl2). H
L-rhamnopyranosyl-(1Ǟ3)-2,4-di-O-
1
NMR (300 MHz, CDCl3): δ = 7.43–7.28 (m, 10 H, Ar-H), 5.46
(dd, J3,4 = 9.9, J3,4 = 3.3 Hz, 1 H, 3B-H), 5.18 (dd, J2,3 = 3.3, J2,1
= 1.8 Hz, 1 H, 2B-H), 5.08 (t, J4,3 = J4,5 = 9.9 Hz, 1 H, 4B-H), 5.01
Methyl 2,3,4-Tri-O-acetyl-α-
L-rhamnopyranosyl-(1Ǟ3)-2-O-allyl-4-
O-benzyl-α- -rhamnopyranoside (11): [α]D
L
=
–50.6 (c 1.8,
=
1
CH2Cl2). H NMR (200 MHz, CDCl3): δ = 7.30 (m, 5 H, Ar-H), (s, 1 H, 1B-H), 4.90 (d, Jgem = 11.7 Hz, 1 H, OCHHPh), 4.79 (d,
5.96 (m, 1 H, OCH2CH=CH2), 5.39–5.26 (m, 3 H, 2B-H, 3B-H, Jgem = 12.0 Hz, 1 H, OCHHPh), 4.67 (m, 2 H, 1A-H, OCHHPh),
trans OCH2CH=CHH), 5.23 (d, Jvic 10.4 Hz, H, cis 4.59 (d, Jgem = 12.0 Hz, 1 H, OCHHPh), 4.20 (dq, J5,4 = 9.9, J5,6
=
1
OCH2CH=CHH), 5.04 (t, J4,3 = J4,5 = 9.5 Hz, 1 H, 4B-H), 5.03 (s,
1 H, 1B-H), 4.80 (d, Jgem = 11.0 Hz, 1 H, OCHHPh), 4.65 (s, 1 H,
= 6.0 Hz, 1 H, 5B-H), 4.15 (dd, J3,2 = 10.2, J3,4 = 2.7 Hz, 1 H, 3A-
H), 3.98 (dd, J2,3 = 10.2, J2,1 = 3.6 Hz, 1 H, 2A-H), 3.84 (q, J5,6
6.0 Hz, 1 H, 5A-H), 3.68 (d, J3,4 = 2.7 Hz, 1 H, 4A-H), 3.35 (s, 3
=
1A-H), 4.62 (d, Jgem = 11.0 Hz, 1 H, OCHHPh), 4.22 (dd, Jgem
=
13.0, Jvic = 5.6 Hz, 1 H, OCHHCH=CH2), 4.07 (dd, Jgem = 13.0,
Jvic = 5.6 Hz, OCHHCH=CH2), 4.04–3.97 (m, 2 H, 3A-H, 5B-H),
3.65–3.56 (m, 3 H, 2A-H, 4A-H, 5A-H), 3.32 (s, 3 H, OCH3), 2.06,
2.05, 1.97 (3 s, 9 H, 3 COCH3), 1.30 (d, J6,5 = 5.7 Hz, 3 H, 6A-H),
H, OCH3), 2.16, 2.02, 2.00 (3 s, 9 H, 3 CH3CO), 1.16 (d, J6,5 =
6.0 Hz, 3 H, 6A-H), 1.12 (d, J6,5 = 6.0 Hz, 3 H, 6B-H) ppm. 13C
NMR (CDCl3, 50 MHz): δ = 170.4, 170.0, 169.9 (3 CO), 138.3,
138.2 (2 Cipso-Bn), 129.0–127.7 (C-Ar), 98.4, 93.9 (C-1A, C-1B),
1.21 (d, J6,5 = 6.3 Hz, 3 H, 6B-H) ppm. 13C NMR (CDCl3, 75.5, 74.6, 74.5, 74.4, 73.3, 71.1, 70.3, 68.9, 66.6, 65.8 (C-2A, C-2B,
50 MHz):
δ
=
169.9–169.8 (3 CO), 138.1 (Cipso-Bn), 134.9
C-3A, C-3B, C-4A, C-4B, C-5A, C-5B, 2 OCH2Ph), 55.3 (OCH3),
(OCH2CH=CH2), 128.3–127.5 (C-Ar), 117.4 (OCH2CH=CH2), 20.9, 20.7, 20.6 (3 CH3CO), 17.5, 16.7 (C-6A, C-6B) ppm. MS
99.1, 98.4 (C-1A, C-1B), 80.6, 78.3, 77.7, 75.3, 72.0, 71.1, 69.8, 69.1,
67.9, 66.8 (C-2A, C-2B, C-3A, C-3B, C-4A, C-4B, C-5A, C-5B,
(MALDI-TOF): calcd. for C33H42O12 [M]+ 630.27; found 653.01
[M + Na]+. C33H42O12 (630.68): calcd. C 62.85, H 6.71; found C
OCH2Ph, OCH2CH=CH2), 54.6 (OCH3), 20.8–20.7 (3 CH3CO), 62.82, H 6.72.
17.9, 17.4 (C-6A, C-6B) ppm. MS (MALDI-TOF): calcd. for
Methyl
benzyl-β-
2,3,4-Tri-O-acetyl-α-
D-fucopyranoside (15): [α]D = –61.0 (c = 2.0, CH2Cl2). H
L-rhamnopyranosyl-(1Ǟ3)-2,4-di-O-
C29H40O12 [M]+ 580.25; found 603.00 [M + Na]+. C29H40O12
(580.62): calcd. C 59.99, H 6.94; found C 60.09, H 6.99.
1
NMR (300 MHz, CDCl3): δ = 7.42–7.27 (m, 10 H, Ar-H), 5.40
(dd, J3,4 = 9.9, J3,4 = 3.3 Hz, 1 H, 3B-H), 5.18 (dd, J2,3 = 3.3, J2,1
= 1.8 Hz, 1 H, 2B-H), 5.03 (t, J4,3 = J4,5 = 9.9 Hz, 1 H, 4B-H), 4.96
Methyl
2,3,4-Tri-O-acetyl-α-
L-rhamnopyranosyl-(1Ǟ3)-2,4-di-O-
benzyl-α-
D-quinovopyranoside (12): [α]D = –17.3 (c = 1.8, CH2Cl2).
1H NMR (200 MHz, CDCl3): δ = 7.34–7.26 (m, 10 H, Ar-H), 5.38– (s, 1 H, 1B-H), 4.93 (d, Jgem = 10.5 Hz, 1 H, OCHHPh), 4.91 (d,
5.27 (m, 3 H, 1B-H, 2B-H, 3B-H), 4.97 (t, J4,3 = J4,5 = 10.0 Hz, 1
H, 4B-H), 4.84 (d, Jgem = 11.2 Hz, 1 H, OCHHPh), 4.68 (d, Jgem
Jgem = 11.4 Hz, 1 H, OCHHPh), 4.71 (d, Jgem = 10.5 Hz, 1 H,
OCHHPh), 4.60 (d, Jgem = 11.4 Hz, 1 H, OCHHPh), 4.26 (d, J1,2
=
12.0 Hz, 1 H, OCHHPh), 4.61 (d, Jgem = 11.2 Hz, 1 H, OCHHPh), = 7.2 Hz, 1 H, 1A-H), 4.16 (dq, J5,4 = 9.9, J5,6 = 6.0 Hz, 1 H, 5B-
4.55 (d, Jgem = 12.0 Hz, 1 H, OCHHPh), 4.45 (d, J1,2 = 3.4 Hz, 1
H, 1A-H), 4.11 (t, J3,4 = J3,2 = 9.4 Hz, 1 H, 3A-H), 4.02 (dq, J5,4
H), 3.74 (m, 2 H, 2A-H, 3A-H), 3.56 (s, 1 H, 4A-H), 3.55 (s, 3 H,
OCH3), 3.48 (q, J5,6 = 6.3 Hz, 1 H, 5A-H), 2.15, 2.01, 2.00 (3 s, 9
=
10.0, J5,6 = 6.2 Hz, 1 H, 5B-H), 3.76 (dq, J5,4 = 9.4, J5,6 = 6.4 Hz, H, 3 CH3CO), 1.23 (d, J6,5 = 6.3 Hz, 3 H, 6A-H), 0.96 (d, J6,5
1 H, 5A-H), 3.51 (dd, J2,3 = 9.4, J2,1 = 3.4 Hz, 1 H, 2A-H), 3.30 (s,
6.0 Hz, 3 H, 6B-H) ppm. 13C NMR (CDCl3, 50 MHz): δ = 170.2,
3 H, OCH3), 3.09 (t, J4,3 = J4,5 = 9.4 Hz, 1 H, 4A-H), 2.07, 1.99, 169.9, 169.7 (3 CO), 138.6, 138.2 (2 Cipso-Bn), 129.0–127.4 (C-Ar),
=
1.91 (3 s, 9 H, 3 CH3CO), 1.27 (d, J6,5 = 6.4 Hz, 3 H, 6A-H), 0.88
(d, J6,5 = 6.2 Hz, 3 H, 6B-H) ppm. 13C NMR (CDCl3, 50 MHz): δ
= 170.1, 169.9, 169.8 (3 CO), 137.9, 137.6 (2 Cipso-Bn), 128.4–127.2
(C-Ar), 97.6, 97.1 (C-1A, C-1B), 82.4, 81.0, 75.6, 74.9, 72.7, 70.9,
105.0, 94.0 (C-1A, C-1B), 77.7, 77.3, 75.3, 75.1, 75.0, 71.6, 70.4,
70.2, 69.0, 66.4 (C-2A, C-2B, C-3A, C-3B, C-4A, C-4B, C-5A, C-5B,
2 OCH2Ph), 56.9 (OCH3), 20.9–20.8 (3 CH3CO), 17.2, 17.0 (C-6A,
C-6B) ppm. MS (MALDI-TOF): calcd. for C33H42O12 [M]+ 630.27;
69.7, 69.2, 66.5, 66.1 (C-2A, C-2B, C-3A, C-3B, C-4A, C-4B, C-5A, found 653.15 [M + Na]+. C33H42O12 (630.68): calcd. C 62.85, H
C-5B, 2 OCH2Ph), 54.9 (OCH3), 20.7–20.6 (3 CH3CO), 17.8, 16.9
(C-6A, C-6B) ppm. MS (MALDI-TOF): calcd. for C33H42O12 [M]+
630.27; found 653.11 [M + Na]+. C33H42O12 (630.68): calcd. C
62.85, H 6.71; found C 62.59, H 6.59.
6.71; found C 62.75, H 6.62.
Methyl 2,3,4-Tri-O-acetyl-α-
L
-rhamnopyranosyl-(1Ǟ3)-4-O-allyl-2-
O-benzyl-α-L-rhamnopyranoside (16): [α]D = –40.1 (c = 2.0,
CH2Cl2). 1H NMR (300 MHz, CDCl3): δ = 7.41–7.28 (m, 5 H, Ar-
H), 5.87 (m, 1 H, OCH2CH=CH2), 5.34 (m, 2 H, 1B-H, 3B-H), 5.24
Methyl
2,3,4-Tri-O-acetyl-α-L-rhamnopyranosyl-(1Ǟ3)-2,4-di-O-
benzyl-β-D-quinovopyranoside (13): [α]D = –50.3 (c = 3.0, CH2Cl2). (d, Jvic = 16.8 Hz, 1 H, OCH2CH=CHH), 5.10 (d, Jvic = 9.9 Hz, 1
1H NMR (200 MHz, CDCl3): δ = 7.33–7.26 (m, 10 H, Ar-H), 5.38 H, OCH2CH=CHH), 5.01 (m, 2 H, 2B-H, 4B-H), 4.75 (d, Jgem
=
=
(d, J1,2 = 1.0 Hz, 1 H, 1B-H), 5.32–5.23 (m, 2 H, 2B-H, 3B-H), 4.98–
4.81 (m, 3 H, 4B-H, 2 OCHHPh), 4.70 (d, Jgem = 11.4 Hz, 1 H,
OCHHPh), 4.56 (d, Jgem = 11.8 Hz, 1 H, OCHHPh), 4.27 (d, J1,2
= 7.8 Hz, 1 H, 1A-H), 4.03 (dq, J5,4 = 10.0, J5,6 = 6.2 Hz, 1 H, 5B-
H), 3.83 (t, J3,4 = J3,2 = 9.2 Hz, 1 H, 4A-H), 3.54 (s, 3 H, OCH3),
3.48–3.38 (m, 2 H, 2A-H, 5A-H), 3.15 (t, J3,2 = J3,4 = 9.2 Hz, 1 H,
12.3 Hz, 1 H, OCHHPh), 4.66 (br. s, 1 H, 1A-H), 4.64 (d, Jgem
12.3 Hz, 1 H, OCHHPh), 4.25 (dd, Jgem = 12.2, Jvic = 5.7 Hz, 1
H, OCHHCH=CH2), 4.10 (dd, Jgem = 12.4, Jvic = 5.7 Hz, 1 H,
OCHHCH=CH2), 3.94 (dd, J3,4 = 9.3, J3,2 = 3.3 Hz, 1 H, 3A-H),
3.80 (dq, J5,4 = 9.6, J5,6 = 6.3 Hz, 1 H, 5B-H), 3.65 (dd, J2,3 = 3.0,
J2,1 = 1.8 Hz, 1 H, 2A-H), 3.58 (dq, J5,4 = 9.6, J5,6 = 6.3 Hz, 1 H,
3A-H), 2.03, 1.97, 1.90 (3 s, 9 H, 3 CH3CO), 1.37 (d, J6,5 = 6.0 Hz, 5A-H), 3.46 (t, J4,3 = J4,5 = 9.6 Hz, 1 H, 4A-H), 3.30 (s, 3 H, OCH3),
3 H, 6A-H), 0.87 (d, J6,5 = 6.2 Hz, 3 H, 6B-H) ppm. 13C NMR
2.10, 2.02, 1.97 (3 s, 9 H, 3 CH3CO), 1.29 (d, J6,5 = 6.3 Hz, 3 H,
(CDCl3, 50 MHz): δ = 170.1, 169.8, 169.7 (3 CO), 138.0, 137.7 (2 6A-H), 1.09 (d, J6,5 = 6.3 Hz, 3 H, 6B-H) ppm. 13C NMR (CDCl3,
Cipso-Bn), 128.2–127.3 (C-Ar), 104.2, 97.2 (C-1A, C-1B), 82.9, 82.0, 75 MHz): 169.7 (3 CO), 138.0 (Cipso-Bn), 134.6
δ
=
76.3, 75.2, 74.3, 71.1, 70.8, 69.4, 69.1, 66.1 (C-2A, C-2B, C-3A, C-
(OCH2CH=CH2), 128.3–127.5 (C-Ar), 116.7 (OCH2CH=CH2),
3B, C-4A, C-4B, C-5A, C-5B, 2 OCH2Ph), 56.9 (OCH3), 20.7–20.6
99.2, 98.3 (C-1A, C-1B), 80.4, 78.3, 77.7, 74.1, 72.4, 71.1, 69.8, 69.0,
Eur. J. Org. Chem. 2008, 5704–5714
© 2008 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
5709

L. Cirillo, E. Bedini, M. Parrilli
FULL PAPER
68.0, 66.8 (C-2A, C-2B, C-3A, C-3B, C-4A, C-4B, C-5A, C-5B,
purified by chromatography (8 to 16% ethyl acetate in toluene) to
OCH2Ph, OCH2CH=CH2), 54.6 (OCH3), 20.7–20.6 (3 CH3CO), afford 20 (129 mg, 64%) as a yellowish oil. [α]D = +26.5 (c = 2.0,
17.8, 17.4 (C-6A, C-6B) ppm. MS (MALDI-TOF): calcd. for
C29H40O12 [M]+ 580.25; found 603.18 [M + Na]+. C29H40O12
(580.62): calcd. C 59.99, H 6.94; found C 59.75, H 6.82.
CH2Cl2). 1H NMR (400 MHz, CDCl3): δ = 7.37–7.19 (m, 15 H,
Ar-H), 5.91 (m, 1 H, OCH2CH=CH2), 5.26 (dd, Jvic = 17.2, Jgem
= 1.6 Hz, 1 H, trans OCH2CH=CHH), 5.16–5.13 (m, 2 H, cis
OCH2CH=CHH, 1B-H), 4.87 (d, Jgem = 11.0 Hz, 1 H, OCHHPh),
4.78 (d, Jgem = 11.0 Hz, 1 H, OCHHPh), 4.70 (s, 2 H, OCH2Ph),
4.64 (s, 1 H, 1A-H), 4.63 (d, Jgem = 11.0 Hz, 1 H, OCHHPh), 4.62
Methyl 2,3,4-Tri-O-acetyl-β-
L-fucopyranosyl-(1Ǟ2)-3,4-di-O-ben-
1
zyl-α- -rhamnopyranoside (17): [α]D = +32.0 (c = 1.8, CH2Cl2). H
D
NMR (300 MHz, CDCl3): δ = 7.46–7.27 (m, 10 H, Ar-H), 5.33
(dd, J2,3 = 10.2, J2,1 = 8.4 Hz, 1 H, 2B-H), 5.23 (d, J4,3 = 3.3 Hz, 1
H, 4B-H), 5.01 (dd, J3,2 = 10.2, J3,4 = 3.3 Hz, 1 H, 3B-H), 4.90–
4.74 (m, 4 H, 1B-H, 3 OCHHPh), 4.54 (d, Jgem = 10.8 Hz, 1 H,
(d, Jgem = 11.6 Hz, 1 H, OCHHPh), 4.07 (dd, Jgem = 11.8, Jvic
=
6.6 Hz, 1 H, OCHHCH=CH2), 4.05 (dd, Jgem = 11.8, Jvic = 6.6 Hz,
1 H, OCHHCH=CH2), 4.00 (d, J2,1 = 1.3 Hz, 1 H, 2B-H), 3.80 (m,
1 H, 5B-H), 3.75–3.61 (m, 3 H, 3A-H, 3B-H, 2A-H), 3.66 (m, 1 H,
5A-H), 3.58 (t, J4,5 = J4,3 = 9.3 Hz, 1 H, 4B-H), 3.42 (t, J4,5 = J4,3
= 9.3 Hz, 1 H, 4A-H), 3.31 (s, 3 H, OCH3), 1.32 (d, J6,5 = 5.8 Hz,
3 H, 6A-H), 1.25 (d, J6,5 = 6.0 Hz, 3 H, 6B-H) ppm. 13C NMR
(CDCl3, 50 MHz): δ = 138.7, 138.2, 138.1 (3 Cipso-Bn), 134.6
(OCH2CH=CH2), 128.4–127.8 (C-Ar), 117.2 (OCH2CH=CH2),
100.8, 98.6 (C-1A, C-1B), 81.1, 79.9, 79.5, 77.3, 76.7, 75.3, 75.1,
72.7, 70.9, 69.0, 67.9, 67.8 (C-2A, C-2B, C-3A, C-3B, C-4A, C-4B, C-
5A, C-5B, 3 OCH2Ph, OCH2CH=CH2), 54.9 (OCH3), 18.2 (C-6A,
C-6B) ppm. MS (MALDI-TOF): calcd. for C37H46O9 [M]+ 634.31;
found 657.33 [M + Na]+. C37H46O9 (634.76): calcd. C 70.01, H
7.30; found C 70.18, H 7.45.
OCHHPh), 4.50 (br. s, 1 H, 1A-H), 4.05 (dd, J3,4 = 8.4, J3,2
=
2.1 Hz, 1 H, 3A-H), 3.86 (br. s, 1 H, 2A-H), 3.79 (q, J5,6 = 6.3 Hz,
1 H, 5B-H), 3.60 (m, 2 H, 4A-H, 5A-H), 3.26 (s, 3 H, OCH3), 2.18,
1.97, 1.81 (3 s, 9 H, 3 CH3CO), 1.27 (d, J6,5 = 6.2 Hz, 3 H, 6A-H),
1.19 (d, J6,5 = 6.3 Hz, 3 H, 6B-H) ppm. 13C NMR (CDCl3,
75 MHz): δ = 170.4, 170.0, 169.3 (3 CO), 138.8, 138.2 (2 Cipso-Bn),
128.4–127.3 (C-Ar), 101.6, 99.7 (C-1A, C-1B), 80.2, 80.1, 77.5, 74.8,
73.4, 71.6, 70.4, 69.6, 69.0, 67.7 (C-2A, C-2B, C-3A, C-3B, C-4A, C-
4B, C-5A, C-5B, 2 OCH2Ph), 54.4 (OCH3), 20.6–20.5 (3 CH3CO),
17.9, 16.1 (C-6A, C-6B) ppm. MS (MALDI-TOF): calcd. for
C33H42O12 [M]+ 630.27; found 653.09 [M + Na]+. C33H42O12
(630.68): calcd. C 62.85, H 6.71; found C 62.77, H 6.65.
Methyl
2-O-Acetyl-3-O-allyl-4-O-benzyl-α-
D-rhamnopyranosyl-
Methyl 2,3,4-Tri-O-acetyl-α-
L-rhamnopyranosyl-(1Ǟ3)-4-O-acetyl-
(1Ǟ3)-2,4-di-O-benzyl-α-
D-rhamnopyranoside (21): Alcohol 20
2-O-benzyl-α- -rhamnopyranoside (18): Compound 16 (30.4 mg,
L
(67.0 mg, 106 µmol) was dissolved in 1:1 Ac2O/pyridine (1.5 mL).
The solution was stirred overnight at room temp. and then co-evap-
orated four times with toluene. The residue was dissolved in
CH2Cl2 and washed with water. The organic layer was collected,
dried with anhydrous Na2SO4, filtered, and concentrated. The resi-
due was purified by chromatography (6% ethyl acetate in toluene)
to give 21 (71.0 mg, 99%) as a colorless oil. [α]D = +28.2 (c = 0.9,
CH2Cl2). 1H NMR (300 MHz, CDCl3): δ = 7.41–7.26 (m, 15 H,
Ar-H), 5.87 (m, 1 H, OCH2CH=CH2), 5.44 (br. s, 1 H, 2B-H), 5.25
(d, Jvic = 17.4 Hz, 1 H, trans OCH2CH=CHH), 5.13–5.10 (m, 2 H,
cis OCH2CH=CHH, 1A-H), 4.94 (d, Jgem = 11.0 Hz, 1 H,
OCHHPh), 4.83 (d, Jgem = 11.0 Hz, 1 H, OCHHPh), 4.72 (s, 2 H,
OCH2Ph), 4.66–4.61 (m, 3 H, 2 OCHHPh, 1B-H), 4.16–4.06 (m, 2
H, OCHHCH=CH2, 3A-H), 3.98 (dd, Jgem = 12.0, Jvic = 5.4 Hz, 1
H, OCHHCH=CH2), 3.88 (dd, J3,2 = 3.3, J3,4 = 9.3 Hz, 1 H, 3B-
H), 3.85 (m, 1 H, 5B-H), 3.71 (br. s, 1 H, 2A-H), 3.65 (t, J4,5 = J4,3
52.2 µmol) was dissolved in 1:1 (v/v) CH2Cl2/MeOH (0.6 mL) and
then treated with PdCl2 (3.7 mg, 20.9 µmol). The mixture was vig-
orously stirred at room temp. for 2 h and then filtered through a
Celite pad, diluted with CH2Cl2, and washed with water. The or-
ganic phase was collected, dried with anhydrous Na2SO4, filtered,
and concentrated. The residue was dissolved in 1:1 (v/v) Ac2O/py
(1.0 mL) and stirred at room temp. overnight. The solution was
then concentrated. The residue was diluted with CH2Cl2 and the
resulting solution washed with 1  HCl. The organic phase was
collected, dried with anhydrous Na2SO4, filtered, and concentrated.
The residue was purified by chromatography (10 to 50% ethyl ace-
tate in petroleum ether) to give 18 (22.9 mg, 75%) as a yellowish
1
oil. [α]D = –34.7 (c = 1.1, CH2Cl2). H NMR (200 MHz, CDCl3):
δ = 7.37 (m, 5 H, Ar-H), 5.30 (dd, J3,4 = 10.0, J3,2 = 3.2 Hz, 1 H,
3B-H), 5.21 (t, J4,3 = J4,5 = 9.8 Hz, 1 H, 4A-H), 5.12 (dd, J2,3 = 3.2,
J2,1 = 2.0 Hz, 1 H, 2B-H), 5.02 (t, J4,3 = J4,5 = 10.0 Hz, 1 H, 4B-
H), 4.89 (d, J1,2 = 1.6 Hz, 1 H, 1B-H), 4.74–4.68 (m, 3 H, 1A-H,
OCH2Ph), 4.00 (dd, J3,4 = 9.8, J3,2 = 3.2 Hz, 1 H, 3A-H), 3.82 (dq,
J5,4 = 9.8, J5,6 = 6.2 Hz, 1 H, 5A-H), 3.70 (m, 2 H, 2A-H, 5B-H),
3.33 (s, 3 H, OCH3), 2.13, 2.12, 2.03, 1.99 (4 s, 12 H, 4 CH3CO),
1.20 (d, J6,5 = 6.2 Hz, 3 H, 6B-H), 1.07 (d, J6,5 = 6.2 Hz, 3 H, 6A-
H) ppm. 13C NMR (CDCl3, 50 MHz): δ = 170.2, 170.1, 170.0,
169.6 (4 CO), 138.0 (Cipso-Bn), 128.5–127.6 (C-Ar), 98.6, 98.5 (C-
1A, C-1B), 76.9, 72.7, 72.6, 71.2, 71.1, 70.2, 68.6, 66.9, 66.8 (C-2A,
C-2B, C-3A, C-3B, C-4A, C-4B, C-5A, OCH2Ph), 54.9 (OCH3), 20.9–
20.7 (4 CH3CO), 17.6, 17.4 (C-6A, C-6B) ppm. MS (MALDI-TOF):
calcd. for C28H38O13 [M]+ 582.23; found 605.09 [M + Na]+.
C28H38O13 (582.59): calcd. C 57.72, H 6.57; found C 57.57, H 6.62.
= 9.0 Hz, 1 H, 4B-H), 3.41 (m, 1 H, 5A-H), 3.36 (t, J4,5 = J4,3
=
9.6 Hz, 1 H, 4A-H), 3.31 (s, 3 H, OCH3), 2.09 (s, 3 H, COCH3),
1.32 (d, J6,5 = 5.4 Hz, 3 H, 6A-H), 1.29 (d, J6,5 = 5.7 Hz, 3 H, 6B-
H) ppm. 13C NMR (CDCl3, 75 MHz): δ = 169.9 (CO), 138.8,
138.1, 138.0 (3 Cipso-Bn), 134.6 (OCH2CH=CH2), 128.4–127.5 (C-
Ar), 117.1 (OCH2CH=CH2), 99.2, 98.5 (C-1A, C-1B), 81.0, 80.9,
79.9, 77.7, 77.4, 77.0, 75.2, 72.8, 70.6, 69.1, 68.2, 67.9 (C-2A, C-2B,
C-3A, C-3B, C-4A, C-4B, C-5A, C-5B, 3 OCH2Ph, OCH2CH=CH2),
54.6 (OCH3), 20.9 (CH3CO), 18.0, 17.9 (C-6A, C-6B) ppm. MS
(MALDI-TOF): calcd. for C39H48O10 [M]+ 676.32; found 699.29
[M + Na]+. C39H48O10 (676.79): calcd. C 69.21, H 7.15; found C
69.15, H 7.09.
Methyl
3-O-Allyl-2-O-benzoyl-4-O-benzyl-α-
D-rhamnopyranosyl-
Methyl 3-O-Allyl-4-O-benzyl-α-
D-rhamnopyranosyl-(1Ǟ3)-2,4-di-
(1Ǟ3)-2,4-di-O-benzyl-α-D-rhamnopyranoside (22): Alcohol 21
O-benzyl-α- -rhamnopyranoside (20): Compound 19 (250 mg,
D
(86.3 mg, 136 µmol) was dissolved in pyridine (1.0 mL), treated
with BzCl (40 µL, 345 µmol), and stirred overnight at room temp.
The mixture was diluted with CH2Cl2 and washed with 1  HCl
and water. The organic layer was collected, dried with anhydrous
Na2SO4, filtered, concentrated, and purified by chromatography (6
to 9% ethyl acetate in toluene) to give 22 (83.0 mg, 83%) as a
317 µmol) was dissolved in dry DMF (5.0 mL) under Ar and then
NaNH2 (542 mg, 13.9 mmol) was added. The mixture was stirred
at 70 °C for 48 h and then diluted with MeOH. AcOH was added
dropwise until the pH was neutral. The solution was concentrated
and the residue was dissolved in CH2Cl2 and washed with 1 
NaHCO3 and brine. The organic layer was collected, dried with
anhydrous Na2SO4, filtered, and concentrated. The residue was
1
colorless oil. [α]D = –0.8 (c = 0.9, CH2Cl2). H NMR (200 MHz,
CDCl3):
δ = 8.06–7.24 (m, 20 H, Ar-H), 5.88 (m, 1 H,
5710
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© 2008 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Org. Chem. 2008, 5704–5714

Acetolysis of 6-Deoxysugar Disaccharide Building Blocks
OCH2CH=CH2), 5.71 (dd, J2,1 = 1.6, J2,3 = 3.0 Hz, 1 H, 2B-H),
5.24 (dd, Jvic = 15.6, Jgem = 1.8 Hz, 1 H, trans OCH2CH=CHH),
5.26 (br. s, 1 H, 1B-H), 5.09 (dd, Jvic = 10.2, Jgem = 1.8 Hz, 1 H,
cis OCH2CH=CHH), 4.98 (d, Jgem = 11.0 Hz, 1 H, OCHHPh),
4.92 (d, Jgem = 11.0 Hz, 1 H, OCHHPh), 4.77 (s, 2 H, OCHHPh),
4.67–4.62 (m, 3 H, 2 OCHHPh, 1A-H), 4.22 (dd, Jgem = 11.5, Jvic
3.1 Hz, 1 H, 3A-H), 3.82–3.75 (m, 3 H, 2A-H, 5A-H, 5B-H), 2.19,
2.11, 2.08, 2.06, 1.99 (5 s, 15 H, 4 CH3CO), 1.18 (d, J6,5 = 6.0 Hz,
6 H, 6A-H, 6B-H) ppm. 13C NMR (CDCl3, 75 MHz): δ = 170.6,
170.3, 169.3, 169.2, 168.6 (5 CO), 138.1 (Cipso-Bn), 129.0–127.6 (C-
Ar), 101.6 (C-1B), 92.6 (C-1B), 76.2, 76.1, 73.6, 72.8, 71.2, 70.3,
69.3, 69.2, 68.9 (C-2A, C-2B, C-3A, C-3B, C-4A, C-4B, C-5A, C-5B,
OCH2Ph), 21.1, 21.0, 20.7, 20.6, 20.5 (5 CH3CO), 17.5, 16.1 (C-6A,
C-6B) ppm. MS (MALDI-TOF): calcd. for C29H38O14 [M]+ 610.23;
found 632.99 [M + Na]+. C29H38O14 (610.60): calcd. C 57.04, H
=
5.2 Hz,
1
H, OCHHCH=CH2), 4.16–3.88 (m,
4
H,
=
OCHHCH=CH2, 3A-H, 5A-H, 5B-H), 3.77 (dd, J2,1 = 2.0, J2,3
3.0 Hz, 1 H, 2A-H), 3.71–3.67 (m, 2 H, 3B-H, 4A-H), 3.54 (t, J4,5
=
J4,3 = 9.2 Hz, 1 H, 4B-H), 3.33 (s, 3 H, OCH3), 1.36–1.30 (m, 6 H, 6.27; found C 56.96, H 6.20.
6A-H, 6B-H) ppm. 13C NMR (CDCl3, 50 MHz): δ = 165.4 (CO),
Acetyl 2,3,4-Tri-O-acetyl-β-
L-fucopyranosyl-(1Ǟ2)-5-O-acetyl-3-O-
138.7, 138.1, 138.0 (3 Cipso-Bn), 134.7 (OCH2CH=CH2), 133.0
(Cipso-Bz), 129.8–127.5 (C-Ar), 117.0 (OCH2CH=CH2), 99.2, 98.6
(C-1A, C-1B), 80.9, 80.0, 77.7, 77.5, 75.3, 75.1, 72.8, 70.5, 69.6, 69.5,
68.3, 67.9 (C-2A, C-2B, C-3A, C-3B, C-4A, C-4B, C-5A, C-5B, 3
OCH2Ph, OCH2CH=CH2), 54.6 (OCH3), 18.2, 17.9 (C-6A, C-
6B) ppm. MS (MALDI-TOF): calcd. for C44H50O10 [M]+ 738.34;
found 761.39 [M + Na]+. C44H50O10 (738.86): calcd. C 71.52, H
6.82; found C 71.45, H 6.77.
benzyl-α- -rhamnofuranoside (25): [α]D = +24.6 (c = 1.1, CH2Cl2).
D
1H NMR (200 MHz, CDCl3): δ = 7.36 (m, 5 H, Ar-H), 6.20 (d,
J1,2 = 0.8 Hz, 1 H, 1A-H), 5.31 (dd, J2,3 = 10.6, J2,1 = 7.8 Hz, 1 H,
2B-H), 5.25 (d, J4,3 = 3.4 Hz, 1 H, 4B-H), 5.04–4.97 (m, 2 H, 3B-H,
5A-H), 4.84 (d, Jgem = 11.8 Hz, 1 H, OCHHPh), 4.64–4.54 (m, 3
H, 1B-H, 3A-H, OCHHPh), 4.38 (dd, J4,5 = 9.8, J4,3 = 3.2 Hz, 1 H,
4A-H), 3.92 (dd, J2,3 = 5.4, J2,1 = 0.8 Hz, 1 H, 2A-H), 3.84 (q, J5,6
= 6.2 Hz, 1 H, 5B-H), 2.14, 2.10, 2.06, 2.04, 1.99 (5 s, 15 H, 5
CH3CO), 1.27 (d, J6,5 = 6.2 Hz, 3 H, 6A-H), 1.21 (d, J6,5 = 6.2 Hz,
3 H, 6B-H) ppm. 13C NMR (CDCl3, 75 MHz): δ = 170.4, 170.2,
170.1, 170.0, 169.3 (5 CO), 138.1 (Cipso-Bn), 129.0–125.2 (C-Ar),
101.3, 99.4 (C-1A, C-1B), 81.2, 81.0, 76.7, 73.0, 71.3, 70.1, 70.0,
69.5, 68.7 (C-2A, C-2B, C-3A, C-3B, C-4A, C-4B, C-5A, C-5B,
OCH2Ph), 21.4, 21.2, 20.6, 20.5, 20.4 (5 CH3CO), 16.1, 14.7 (C-6A,
C-6B) ppm. MS (MALDI-TOF): calcd. for C29H38O14 [M]+ 610.23;
found 632.90 [M + Na]+. C29H38O14 (610.60): calcd. C 57.04, H
6.27; found C 56.88, H 6.11.
Typical Acetolysis Procedure (ZnCl2 Protocol): Methyl glycoside
(66 µmol) was dissolved in a 2:1 (v/v) Ac2O/AcOH mixture
(1.0 mL), cooled to 5 °C, and then treated with freshly fused ZnCl2
(660 µmol). The solution was stirred at 5 °C until TLC (ethyl ace-
tate in toluene) showed the disappearance of the starting material.
The solution was then diluted with CH2Cl2 and washed with 1 
NaHCO3 and then collected, dried with anhydrous Na2SO4, fil-
tered, and concentrated. The residue was purified by chromatog-
raphy (ethyl acetate in toluene).
Typical Acetolysis Procedure (TFA Protocol): Methyl glycoside
(66 µmol) was dissolved in a 1:1:0.1 (v/v/v) Ac2O/AcOH/TFA mix-
ture (2.1 mL). The solution was stirred at 70 °C until TLC (ethyl
acetate in toluene) showed disappearance of the starting material.
The reaction was quenched by cooling to room temp. The mixture
was diluted with CH2Cl2 and washed with 1  NaHCO3. The or-
ganic layer was collected, dried with anhydrous Na2SO4, filtered,
and concentrated. The residue was purified by chromatography
(ethyl acetate in toluene).
Acetyl
3-O-Allyl-2-O-acetyl-4-O-benzyl-α-
D-rhamnopyranosyl-
(1Ǟ3)-5-O-acetyl-2-O-benzyl-
D
-rhamnofuranoside (26): 1H NMR
(400 MHz, CDCl3) (α anomer): δ = 7.34 (m, 10 H, Ar-H), 6.20 (d,
J1,2 = 2.7 Hz, 1 H, 1A-H), 5.92 (m, 1 H, OCH2CH=CH2), 5.30 (dd,
Jvic = 18.0, Jgem = 1.8 Hz, 1 H, trans OCH2CH=CHH), 5.19–5.05
(m, 3 H, 2B-H, 5A-H, cis OCH2CH=CHH), 4.90 (d, Jgem = 11.1 Hz,
1 H, OCHHPh), 4.78 (d, J1,2 = 1.5 Hz, 1 H, 1B-H), 4.66–4.56 (m,
3 H, 3 OCHHPh), 4.39 (t, J3,4 = J3,2 = 4.8 Hz, 1 H, 3A-H), 4.22–
4.01 (m, 4 H, 4A-H, 5B-H, OCH2CH=CH2), 3.94 (dd, J2,3 = 4.8,
J2,3 = 2.7 Hz, 1 H, 2A-H), 3.84 (dd, J3,4 = 9.2, J3,2 = 3.0 Hz, 1 H,
3B-H), 3.38 (t, J4,3 = J4,5 = 4.8 Hz, 1 H, 4B-H), 2.14, 2.06, 2.05 (3
s, 9 H, 3 CH3CO), 1.29 (d, J6,5 = 6.3 Hz, 3 H, 6A-H), 1.18 (d, J6,5
= 6.3 Hz, 3 H, 6B-H) ppm. 13C NMR (CDCl3, 75 MHz) (α an-
omer): δ = 170.0, 169.8, 169.6 (3 CO), 138.7, 137.1 (2 Cipso-Bn),
Acetyl 2,3,4-Tri-O-acetyl-β-
L-fucopyranosyl-(1Ǟ2)-3,4-di-O-benzyl-
α-
D
-rhamnopyranoside (23): [α]D = +27.5 (c = 1.9, CH2Cl2). 1H
NMR (200 MHz, CDCl3): δ = 7.44–7.16 (m, 10 H, Ar-H), 5.98 (d,
J1,2 = 2.0 Hz, 1 H, 1A-H), 5.35 (dd, J2,3 = 10.2, J2,1 = 8.0 Hz, 1 H,
2B-H), 5.25 (d, J4,3 = 3.4 Hz, 1 H, 4B-H), 5.03 (dd, J3,2 = 10.2, J3,4
= 3.4 Hz, 1 H, 3B-H), 4.92–4.74 (m, 4 H, 1B-H, 3 OCHHPh), 4.57
134.5
(OCH2CH=CH2),
128.5–127.4
(C-Ar),
117.3
(OCH2CH=CH2), 99.6, 98.4 (C-1A, C-1B), 81.4, 80.8, 79.8, 77.3,
76.7, 75.0, 72.6, 70.8, 69.4, 68.6, 68.5 (C-2A, C-2B, C-3A, C-3B, C-
4A, C-4B, C-5A, C-5B, 2 OCH2Ph, OCH2CH=CH2), 21.3, 21.1, 21.0
(3 CH3CO), 18.0, 16.4 (C-6A, C-6B) ppm. MS (MALDI-TOF):
calcd. for C35H44O12 [M]+ 656.28; found 679.21 [M + Na]+.
C35H44O12 (656.72): calcd. C 64.01, H 6.75; found C 64.23, H 6.66.
(d, Jgem = 10.6 Hz, 1 H, OCHHPh), 4.11 (dd, J3,4 = 9.0, J3,2
=
3.0 Hz, 1 H, 3A-H), 3.87–3.73 (m, 3 H, 2A-H, 5A-H, 5B-H), 3.65 (t,
J4,3 = J4,5 = 9.4 Hz, 1 H, 4A-H), 2.20, 2.05, 2.00, 1.89 (4 s, 12 H, 4
CH3CO), 1.30 (d, J6,5 = 5.7 Hz, 3 H, 6A-H), 1.18 (d, J6,5 = 6.6 Hz,
3 H, 6B-H) ppm. 13C NMR (CDCl3, 50 MHz): δ = 170.2, 170.1,
168.8, 168.7 (4 CO), 138.3, 138.1 (2 Cipso-Bn), 129.0–127.6 (C-Ar),
101.4 (C-1B), 92.4 (C-1A), 79.7, 78.8, 75.1, 73.5, 71.4, 70.4, 70.3,
69.5, 69.1 (C-2A, C-2B, C-3A, C-3B, C-4A, C-4B, C-5A, C-5B,
OCH2Ph), 21.1, 20.9, 20.6, 20.5 (4 CH3CO), 17.8, 16.0 (C-6A, C-
6B) ppm. MS (MALDI-TOF): calcd. for C34H42O13 [M]+ 658.26;
found 680.89 [M + Na]+. C34H42O13 (658.69): calcd. C 62.00, H
6.43; found C 61.86, H 6.32.
Acetyl
2-O-Acetyl-3-O-allyl-4-O-benzyl-α-
D-rhamnopyranosyl-
(1Ǟ3)-2,4-di-O-benzyl-α-
D-rhamnopyranoside (27): [α]D = +69.6 (c
= 1.0, CH2Cl2). 1H NMR (400 MHz, CDCl3): δ = 7.38–7.26 (m,
15 H, Ar-H), 6.13 (d, J1,2 = 2.0 Hz, 1 H, 1A-H), 5.86 (m, 1 H,
OCH2CH=CH2), 5.43 (dd, J2,1 = 1.8, J2,3 = 3.4 Hz, 1 H, 2B-H),
5.25 (dd, Jvic = 17.0, Jgem = 1.6 Hz, 1 H, trans OCH2CH=CHH),
5.12 (dd, Jvic = 10.0, Jgem = 1.6 Hz, 1 H, cis OCH2CH=CHH), 5.08
(d, J1,2 = 1.6 Hz, 1 H, 1B-H), 4.93 (d, Jgem = 11.0 Hz, 1 H,
Acetyl 2,3,4-Tri-O-acetyl-β-L-fucopyranosyl-(1Ǟ2)-4-O-acetyl-3-O-
benzyl-α- -rhamnopyranoside (24): [α]D = +30 (c = 0.5, CH2Cl2).
D
1H NMR (400 MHz, CDCl3): δ = 7.41–7.27 (m, 5 H, Ar-H), 6.01 OCHHPh), 4.84 (d, Jgem = 11.0 Hz, 1 H, OCHHPh), 4.76 (d, Jgem
(d, J1,2 = 1.8 Hz, 1 H, 1A-H), 5.27–5.21 (m, 3 H, 2B-H, 4A-H, 4B-
H), 4.99 (dd, J3,2 = 10.5, J3,4 = 3.5 Hz, 1 H, 3B-H), 4.87 (d, Jgem
= 11.8 Hz, 1 H, OCHHPh), 4.67 (d, Jgem = 11.8 Hz, 1 H,
OCHHPh), 4.63 (d, Jgem = 10.8 Hz, 1 H, OCHHPh), 4.61 (d, Jgem
=
12.1 Hz, 1 H, OCHHPh), 4.75 (d, Jgem = 12.1 Hz, 1 H, OCHHPh), = 11.0 Hz, 1 H, OCHHPh), 4.09 (dd, Jgem = 12.8, Jvic = 5.5 Hz, 1
4.63 (d, J1,2 = 8.0 Hz, 1 H, 1B-H), 4.04 (dd, J3,4 = 10.0, J3,2 H, OCHHCH=CH2), 4.07 (dd, J3,2 = 3.2, J3,4 = 9.4 Hz, 1 H, 3A-
=
Eur. J. Org. Chem. 2008, 5704–5714
© 2008 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
5711

L. Cirillo, E. Bedini, M. Parrilli
FULL PAPER
H), 4.03 (dd, Jgem = 12.8, Jvic = 5.5 Hz, 1 H, OCHHCH=CH2), Acetyl
3.85 (dd, J3,2 = 3.4, J3,4 = 9.3 Hz, 1 H, 3B-H), 3.78 (m, 2 H, 5A-H, (1Ǟ3)-2,4-di-O-benzyl-α-
3-O-Allyl-2-O-benzoyl-4-O-benzyl-α-
-rhamnopyranoside (29): [α]D = –2.5 (c =
5B-H), 3.72 (dd, J2,1 = 1.6, J2,3 = 2.2 Hz, 1 H, 2A-H), 3.70 (t, J4,5 1.2, CH2Cl2). H NMR (200 MHz, CDCl3): δ = 8.07–7.16 (m, 20
D-rhamnopyranosyl-
D
1
= J4,3 = 9.4 Hz, 1 H, 4B-H), 3.39 (t, J4,5 = J4,3 = 9.4 Hz, 1 H, 4A-
H), 2.11 (s, 3 H, CH3CO), 2.07 (s, 3 H, CH3CO), 1.32 (d, J6,5
H, Ar-H), 6.14 (d, J1,2 = 2.0 Hz, 1 H, 1A-H), 5.84 (m, 1 H,
OCH2CH=CH2), 5.68 (dd, J2,1 = 1.6, J2,3 = 3.4 Hz, 1 H, 2B-H),
=
6.1 Hz, 3 H, 6A-H), 1.24 (d, J6,5 = 6.2 Hz, 3 H, 6B-H) ppm. 13C 5.25–5.21 (m, 2 H, 1B-H, trans OCH2CH=CHH), 5.08 (dd, Jvic
=
=
NMR (CDCl3, 100 MHz): δ = 170.0, 169.1 (2 CO), 138.6, 137.8,
137.5 (3 Cipso-Bn), 134.6 (OCH2CH=CH2), 129.0–127.6 (C-Ar),
10.2, Jgem = 1.8 Hz, 1 H, cis OCH2CH=CHH), 4.95 (d, Jgem
11.0 Hz, 1 H, OCHHPh), 4.90 (d, Jgem = 11.0 Hz, 1 H, OCHHPh),
117.1 (OCH2CH=CH2), 99.4 (C-1B), 91.2 (C-1A), 80.1, 79.8, 77.4, 4.79 (d, Jgem = 12.0 Hz, 1 H, OCHHPh), 4.72–4.62 (m, 3 H, 3
77.3, 76.7, 75.4, 75.1, 72.6, 70.7, 70.6, 69.2, 69.1 (C-2A, C-2B, C- OCHHPh), 4.19 (dd, Jgem 12.0, Jvic 5.0 Hz, H,
=
=
1
3A, C-3B, C-4A, C-4B, C-5A, C-5B, 3 OCH2Ph, OCH2CH=CH2), OCHHCH=CH2), 4.12–4.05 (m, 2 H, 3A-H, OCHHCH=CH2),
21.0, 20.9 (2 CH3CO), 18.0, 17.9 (C-6A, C-6B) ppm. MS (MALDI- 3.98 (dd, J3,2 = 3.2, J3,4 = 9.2 Hz, 1 H, 3B-H), 3.91–3.65 (m, 4 H,
TOF): calcd. for C40H48O11 [M]+ 704.32; found 727.39 [M +
Na]+. C40H48O11 (704.80): calcd. C 68.16, H 6.86; found C 68.23,
H 6.97.
2A-H, 4A-H, 5A-H, 5B-H), 3.51 (t, J4,5 = J4,3 = 9.6 Hz, 1 H, 4B-H),
2.06 (s, 3 H, CH3CO), 1.32 (d, J6,5 = 6.2 Hz, 3 H, 6B-H), 1.29 (d,
J6,5 = 6.2 Hz, 3 H, 6A-H) ppm. 13C NMR (CDCl3, 50 MHz): δ =
169.2, 165.5 (2 CO), 138.6, 137.8, 137.5 (3 Cipso-Bn), 134.6
(OCH2CH=CH2), 133.1 (Cipso-Bz), 129.8–125.3 (C-Ar), 117.1
(OCH2CH=CH2), 99.5 (C-1B), 91.2 (C-1A), 80.1, 79.9, 77.6, 77.4,
76.7, 75.5, 75.2, 72.6, 72.5, 70.6, 69.6, 68.4 (C-2A, C-2B, C-3A, C-
3B, C-4A, C-4B, C-5A, C-5B, 3 OCH2Ph, OCH2CH=CH2), 21.0
(CH3CO), 18.2, 18.1 (C-6A, C-6B) ppm. MS (MALDI-TOF): calcd.
for C45H50O11 [M]+ 766.34; found 789.42 [M + Na]+. C45H50O11
(766.87): calcd. C 70.48, H 6.57; found C 70.28, H 6.34.
Acetyl
3-O-Allyl-2-O-benzoyl-4-O-benzyl-α-
D-rhamnopyranosyl-
(1Ǟ3)-5-O-acetyl-2-O-benzyl-α-
D
-rhamnofuranoside (28α): [α]D
=
+5.9 (c = 0.8, CH2Cl2). 1H NMR (500 MHz, CDCl3): δ = 8.07–
7.26 (m, 15 H, Ar-H), 6.22 (d, J1,2 = 3.0 Hz, 1 H, 1A-H), 5.87 (m,
1 H, OCH2CH=CH2), 5.38 (dd, J2,3 = 3.4, J2,1 = 2.0 Hz, 1 H, 2B-
H), 5.28 (dd, Jvic
= 18.0, Jgem = 1.5 Hz, 1 H, trans
OCH2CH=CHH), 5.18 (q, J5,6 = J5,4 = 6.0 Hz, 1 H, 5A-H), 5.12
(dd, Jvic = 10.0, Jgem = 1.5 Hz, 1 H, cis OCH2CH=CHH), 4.94 (d,
Jgem = 11.0 Hz, 1 H, OCHHPh), 4.91 (d, J1,2 = 2.0 Hz, 1 H, 1B-
H), 4.64 (m, 3 H, 3 OCHHPh), 4.43 (t, J3,4 = J3,2 = 5.4 Hz, 1 H,
3A-H), 4.20 (m, 2 H, 4A-H, OCHHCH=CH2), 4.09 (m, 2 H, 5B-H,
Acetyl 2,3,4-Tri-O-acetyl-α-
L-rhamnopyranosyl-(1Ǟ3)-5-O-acetyl-
2-O-allyl-α-
L
-rhamnofuranoside (30): 1H NMR (400 MHz, CDCl3):
δ = 6.27 (d, J1,2 = 4.5 Hz, 1 Hβ, 1A-β-H), 6.19 (d, J1,2 = 2.9 Hz, 1
Hα, 1A-α-H), 5.87 (m, 1 Hβ + 1 Hα, OCH2CH=CH2), 5.39 (dd, J3,4
OCHHCH=CH2), 3.96 (m, 2 H, 2A-H, 3B-H), 3.49 (t, J4,5 = J4,3
=
9.0 Hz, 1 H, 4B-H), 2.08 (s, 3 H, CH3CO), 2.06 (s, 3 H, CH3CO), = 9.9, J3,2 = 3.6 Hz, 1 Hα, 3B-β-H), 5.32 (dd, Jvic = 17.2, Jgem
=
1.31 (d, J6,5 = 6.0 Hz, 3 H, 6A-H), 1.21 (d, J6,5 = 6.0 Hz, 3 H, 6B-
1.5 Hz, 1 Hα + 1 Hβ, trans OCH2CH=CHH), 5.26–5.18 (m, 3Hα +
2Hβ, cis OCH2CH=CHH, 2B-α-H, 2B-β-H, 3B-α-H), 5.18–5.01 (m,
H) ppm. 13C NMR (CDCl3, 50 MHz): δ = 169.9, 169.8, 165.5 (3
CO), 138.6, 137.1 (2 Cipso-Bn), 134.6 (OCH2CH=CH2), 133.1 2Hα + 2Hβ, 4B-α-H, 4B-β-H, 5A-α-H, 5A-β-H), 4.78 (d, J1,2 = 1.5 Hz,
(Cipso-Bz), 129.9–127.6 (C-Ar), 117.3 (OCH2CH=CH2), 99.5, 98.3 1 Hα, 1B-α-H), 4.74 (d, J1,2 = 1.7 Hz, 1 Hβ, 1B-β-H), 4.46 (dq, J5,4
(C-1A, C-1B), 81.4, 80.8, 79.7, 77.4, 76.6, 75.0, 72.5, 70.6, 69.7, 68.6, = 9.9, J5,6 = 6.2 Hz, 1 Hβ, 5B-β-H), 4.35 (t, J3,2 = J3,4 = 4.9 Hz, 1
68.5 (C-2A, C-2B, C-3A, C-3B, C-4A, C-4B, C-5A, C-5B, 2 OCH2Ph, Hα, 3A-α-H), 4.26–4.19 (m, 2 Hα + 1 Hβ, 3A-β-H, 4A-α-H, 5B-α-H),
OCH2CH=CH2), 21.4, 21.2 (2 CH3CO), 18.2, 16.4 (C-6A, C- 4.13–4.03 (m, 2 Hα + 2 Hβ, OCH2CH=CH2), 3.99 (dd, J2,3 = 5.9,
6B) ppm. MS (MALDI-TOF): calcd. for C40H46O12 [M]+ 718.30;
found 741.03 [M + Na]+. C40H46O12 (718.79): calcd. C 66.84, H
6.45; found C 66.68, H 6.32.
J2,1 = 4.5 Hz, 1 Hβ, 2A-β-H), 3.94 (dd, J2,3 = 4.6, J2,1 = 2.9 Hz, 1
Hα, 2A-α-H), 3.91 (t, J4,3 = J4,5 = 5.9 Hz, 1 Hβ, 4A-β-H), 2.18 (s, 3
Hβ, CH3CO), 2.13 (2 s, 3 Hα + 3 Hβ, CH3CO), 2.08 (s, 3 Hα,
CH3CO), 2.04 (2 s, 6 Hα, CH3CO), 2.03 (s, 3 Hβ, CH3CO), 2.01 (s,
3 Hβ, CH3CO), 1.99 (s, 3 Hβ, CH3CO), 1.98 (s, 3 Hα, CH3CO),
1.35 (d, J6,5 = 6.2 Hz, 3 Hβ, 6A-β-H), 1.31 (d, J6,5 = 6.3 Hz, 3 Hα,
6A-α-H), 1.17 (d, J6,5 = 6.2 Hz, 3 Hα, 6B-α-H), 1.16 (d, J6,5 = 6.2 Hz,
3 Hβ, 6B-β-H) ppm. 13C NMR (CDCl3, 50 MHz): δ = 170.1–169.6
Acetyl
3-O-Allyl-2-O-benzoyl-4-O-benzyl-α-
D-rhamnopyranosyl-
(1Ǟ3)-5-O-acetyl-2-O-benzyl-α-
D
-rhamnofuranoside (28β): [α]D
=
1
–6 (c = 0.3, CH2Cl2). H NMR (500 MHz, CDCl3): δ = 8.07–7.28
(m, 15 H, Ar-H), 6.25 (d, J1,2 = 4.5 Hz, 1 H, 1A-H), 5.88 (m, 1 H,
OCH2CH=CH2), 5.36 (dd, Jvic = 18.0, Jgem = 1.6 Hz, 1 H, trans
OCH2CH=CHH), 5.30 (dd, J2,3 = 3.4, J2,1 = 2.0 Hz, 1 H, 2B-H),
5.13 (m, 2 H, 5A-H, cis OCH2CH=CHH), 4.95 (d, Jgem = 11.0 Hz,
(5 COα
+ 5 COβ), 133.8 (α OCH2CH=CH2), 133.6 (β
OCH2CH=CH2), 118.4 (α OCH2CH=CH2), 117.7 (β
OCH2CH=CH2), 99.5, 98.4 (C-1A-α, C-1B-α), 98.8, 93.0 (C-1A-β, C-
1B-β), 81.7, 81.0, 78.6, 71.7, 71.0, 69.9, 68.8, 68.7, 67.0 (α C-2A, C-
2B, C-3A, C-3B, C-4A, C-4B, C-5A, C-5B, OCH2CH=CH2), 82.8,
78.2, 72.4, 72.1, 71.5, 70.6, 68.8, 68.7, 66.7 (β C-2A, C-2B, C-3A, C-
3B, C-4A, C-4B, C-5A, C-5B, OCH2CH=CH2), 21.3–20.7 (5
CH3COα + 5 CH3COβ), 17.6, 16.3 (C-6A-α, C-6B-α), 17.5, 16.7 (C-
6A-β, C-6B-β) ppm. MS (MALDI-TOF): calcd. for C25H36O14 [M]+
560.21; found 582.90 [M + Na]+. C25H36O14 (560.55): calcd. C
53.57, H 6.47; found C 53.70, H 6.40.
1 H, OCHHPh), 4.85 (d, J1,2 = 1.8 Hz, 1 H, 1B-H), 4.69 (d, Jgem
=
13.0 Hz, 1 H, OCHHPh), 4.63 (d, Jgem = 11.0 Hz, 1 H, OCHHPh),
4.61 (d, Jgem = 13.0 Hz, 1 H, OCHHPh), 4.32 (dq, J5,4 = 10.0, J5,6
= 6.0 Hz, 1 H, 5B-H), 4.23 (m, 2 H, 3A-H, OCHHCH=CH2), 4.10
(dd, Jgem = 13.0, Jvic = 6.0 Hz, 1 H, OCHHCH=CH2), 4.00 (dd,
J3,4 = 10.0, J3,2 = 3.4 Hz, 1 H, 3B-H), 3.94 (dd, J4,5 = 8.5, J4,3
=
4.0 Hz, 1 H, 4A-H), 3.85 (t, J2,3 = J2,1 = 4.5 Hz, 1 H, 2A-H), 3.50
(t, J4,5 = J4,3 = 10.0 Hz, 1 H, 4B-H), 2.11 (s, 3 H, CH3CO), 2.09 (s,
3 H, CH3CO), 1.36 (d, J6,5 = 6.0 Hz, 3 H, 6A-H), 1.15 (d, J6,5
=
6.0 Hz, 3 H, 6B-H) ppm. 13C NMR (CDCl3, 125 MHz): δ = 170.5,
Acetyl 2,3,4-Tri-O-acetyl-α-
L-rhamnopyranosyl-(1Ǟ3)-2-O-allyl-4-
170.3, 165.6 (3 CO), 138.9, 137.1 (2 Cipso-Bn), 135.2, 134.8
O-benzyl-α- -rhamnopyranoside (31): [α]D
L
=
–39.2 (c 1.4,
=
1
(OCH2CH=CH2,
Cipso-Bz),
129.9–127.4
(C-Ar),
117.3 CH2Cl2). H NMR (300 MHz, CDCl3): δ = 7.32 (m, 5 H, Ar-H),
(OCH2CH=CH2), 99.8, 93.2 (C-1A, C-1B), 82.7, 80.1, 77.7, 77.2, 6.09 (d, J1,2 = 2.1 Hz, 1 H, 1A-H), 5.98 (m, 1 H, OCH2CH=CH2),
76.6, 75.0, 72.6, 70.1, 69.8, 68.6, 68.3 (C-2A, C-2B, C-3A, C-3B, C-
4A, C-4B, C-5A, C-5B, 2 OCH2Ph, OCH2CH=CH2), 21.4, 21.3 (2
CH3CO), 18.1, 16.9 (C-6A, C-6B) ppm. MS (MALDI-TOF): calcd.
for C40H46O12 [M]+ 718.30; found 740.56 [M + Na]+. C40H46O12
(718.79): calcd. C 66.84, H 6.45; found C 66.55, H 6.25.
5.40–5.34 (m, 3 H, 2B-H, 3B-H, trans OCH2CH=CHH), 5.26 (dd,
Jvic = 10.5, Jgem = 1.2 Hz, 1 H, cis OCH2CH=CHH), 5.08 (t, J4,3
= J4,5 = 9.9 Hz, 1 H, 4B-H), 5.05 (br. s, 1 H, 1B-H), 4.84 (d, Jgem
= 11.1 Hz, 1 H, OCHHPh), 4.64 (d, Jgem = 11.1 Hz, 1 H,
OCHHPh), 4.27 (dd, Jgem
= 12.9, Jvic = 5.4 Hz, 1 H,
5712
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© 2008 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Org. Chem. 2008, 5704–5714

Acetolysis of 6-Deoxysugar Disaccharide Building Blocks
OCHHCH=CH2), 4.12–3.98 (m,
OCHHCH=CH2), 3.77 (dq, J5,4 = 9.6, J5,6 = 6.3 Hz, 1 H, 5A-H), 10.0 Hz, 1 HЈ + 1 HЈЈ, 4BЈ-H, 4BЈЈ-H), 4.96 (m, 1 HЈ + 1 HЈЈ, 5AЈ
3.67 (dd, J2,3 = 3.0, J2,1 = 2.1 Hz, 1 H, 2A-H), 3.63 (t, J4,3 = J4,5 H, 5AЈЈ-H), 4.91 (d, J1,2 = 1.8 Hz, 1 HЈ, 1BЈ-H), 4.86 (d, J1,2
3
H, 3A-H, 5B-H,
(dd, J2,3 = 3.0, J2,1 = 1.8 Hz, 1 HЈ, 2BЈ-H), 5.06 (t, J4,3 = J4,5 =
-
=
=
9.6 Hz, 1 H, 4A-H), 2.09, 2.07, 2.06, 1.99 (4 s, 12 H, 4 CH3CO),
1.31 (d, J6,5 = 6.3 Hz, 3 H, 6A-H), 1.20 (d, J6,5 = 6.3 Hz, 3 H, 6B-
H) ppm. 13C NMR (CDCl3, 50 MHz): δ = 170.0, 169.9, 169.8,
1.8 Hz, 1 HЈЈ, 1BЈЈ-H), 4.78 (d, Jgem = 12.0 Hz, 1 HЈ, OCHHPhЈ),
4.69–4.61 (m, 2 HЈ + 1 HЈЈ, OCHHPhЈ, OCHHPhЈЈ), 4.08 (dq, J5,4
= 10.0, J5,6 = 6.2 Hz, 1 HЈ + 1 HЈЈ, 5BЈ-H, 5BЈЈ-H), 3.93 (dd, J3,4
=
169.1 (4 CO), 137.8 (Cipso-Bn), 134.3 (OCH2CH=CH2), 128.4– 8.0, J3,2 = 1.8 Hz, 1 HЈ, 3AЈ-H), 3.89 (dd, J3,4 = 8.0, J3,2 = 3.0 Hz,
127.8 (C-Ar), 117.9 (OCH2CH=CH2), 99.4 (C-1B), 91.2 (C-1A), 1 HЈЈ, 3AЈЈ-H), 3.66 (dd, J2,1 = 5.0, J2,3 = 3.0 Hz, 1 HЈЈ, 2AЈЈ-H),
79.7, 78.5, 76.7, 75.6, 71.8, 70.9, 70.6, 69.8, 69.0, 66.9 (C-2A, C-2B,
3.57 (dd, J2,1 = 6.0, J2,3 = 1.8 Hz, 1 HЈ, 2AЈ-H), 3.53 (s, 3 HЈ,
C-3A, C-3B, C-4A, C-4B, C-5A, C-5B, OCH2Ph, OCH2CH=CH2), OCH3Ј), 3.52 (s, 3 HЈЈ, OCH3ЈЈ), 2.17 (s, 3 HЈЈ, CH3COЈЈ), 2.14 (s,
21.0–20.8 (4 CH3CO), 18.0, 17.5 (C-6A, C-6B) ppm. MS (MALDI-
TOF): calcd. for C30H40O13 [M]+ 608.25; found 630.74 [M +
Na]+. C30H40O13 (608.63): calcd. C 59.20, H 6.62; found C 59.11,
H 6.70.
3 HЈ, CH3COЈ), 2.13 (s, 3 HЈЈ, CH3COЈЈ), 2.11 (s, 3 HЈ, CH3COЈ),
2.07 (s, 3 HЈ, CH3COЈ), 2.06 (s, 3 HЈ + 3 HЈЈ, CH3COЈ, CH3COЈЈ),
2.05 (s, 3 HЈЈ, 3 CH3COЈЈ), 1.97 (s, 6 HЈ + 6 HЈЈ, 2 CH3COЈ, 2
CH3COЈЈ), 1.11 (d, J6,5 = 6.2 Hz, 3 HЈЈ, 6BЈЈ-H), 1.05 (d, J6,5
=
6.2 Hz, 3 HЈ, 6BЈ-H), 1.03 (d, J6,5 = 6.6 Hz, 3 HЈЈ, 6AЈЈ-H), 1.00 (d,
J6,5 = 6.6 Hz, 3 HЈ, 6AЈ-H) ppm. 13C NMR (CDCl3, 75 MHz): δ =
170.4–169.7 (5 COЈ, 5 COЈЈ), 137.6 (Cipso-BnЈ, Cipso-BnЈЈ), 128.5–
127.8 (C-Ar), 98.8, 97.1 (C-1AЈЈ, C-1BЈЈ), 98.5, 97.7 (C-1AЈ, C-1BЈ),
79.1, 76.8, 73.6, 73.1, 71.0, 70.1, 68.9, 68.8, 67.2 (C-2AЈ, C-2BЈ, C-
3AЈ, C-3BЈ, C-4AЈ, C-4BЈ, C-5AЈ, C-5BЈ, OCH2PhЈ), 79.1, 77.2, 73.9,
72.9, 71.1, 70.0, 68.9, 68.8, 67.2 (C-2AЈЈ, C-2BЈЈ, C-3AЈЈ, C-3BЈЈ, C-
4AЈЈ, C-4BЈЈ, C-5AЈЈ, C-5BЈЈ, OCH2PhЈЈ), 57.9 (OCH3Ј), 53.4
2,3,4-Tri-O-acetyl-α-
O-allyl-2-O-benzyl-1-O-methyl-
(500 MHz, CDCl3) (major diastereoisomer): δ = 7.32 (m, 5 H, Ar-
H) , 5 . 99 (d , J1 , 2 = 7 . 0 H z , 1 H, 1A - H ) , 5 . 8 5 ( m , 1 H ,
OCH2CH=CH2), 5.35 (dd, J2,3 = 3.0, J2,1 = 1.5 Hz, 1 H, 2B-H),
L-rhamnopyranosyl-(1Ǟ3)-1,5-di-O-acetyl-4-
1
D
-rhamnose Acetal (32): H NMR
5.24 (dd, J3,4 = 10.2, J3,2 = 3.0 Hz, 1 H, 3B-H), 5.19 (d, Jvic
=
17.5 Hz, 1 H, trans OCH2CH=CHH), 5.08 (m, 2 H, 1B-H, 4B-H),
5.04 (d, Jvic = 10.5 Hz, 1 H, trans OCH2CH=CHH), 4.81 (dq, J5,6
= 6.6, J5,4 = 1.8 Hz, 1 H, 5A-H), 4.62 (s, 2 H, OCH2Ph), 4.15 (m,
3 H, OCH2CH=CH2, 5B-H), 3.80 (m, 2 H, 3A-H, 4A-H), 3.52 (m,
4 H, 2A-H, OCH3), 2.12 (s, 6 H, 2 CH3CO), 2.07 (s, 3 H, CH3CO),
2.02 (s, 3 H, CH3CO), 1.97 (s, 3 H, CH3CO), 1.04 (d, J6,5 = 6.2 Hz,
3 H, 6B-H), 1.02 (d, J6,5 = 6.6 Hz, 3 H, 5A-H) ppm. 13C NMR
(CDCl3, 75 MHz) (major diastereoisomer): δ = 170.5, 170.2, 169.9,
169.8, 169.7 (5 CO), 137.5 (Cipso-Bn), 134.8 (OCH2CH=CH2),
128.5–127.9 (C-Ar), 116.5 (OCH2CH=CH2), 98.7, 98.0 (C-1A, C-
1B), 80.6, 78.8, 77.7, 73.7, 73.5, 71.0, 70.8, 69.8, 69.6, 67.1 (C-2A,
C-2B , C-3A , C-3B , C-4A , C- 4B , C -5A , C- 5B , OCH2 Ph,
OCH2CH=CH2), 57.7 (OCH3), 21.3, 21.2, 20.9, 20.8, 20.7 (5
CH3CO), 17.4, 13.7 (C-6A, C-6B) ppm. MS (MALDI-TOF): calcd.
for C33H46O15 [M]+ 682.28; found 704.73 [M + Na]+. C33H46O15
(682.71): calcd. C 58.06, H 6.79; found C 57.88, H 6.65.
(OCH3ЈЈ), 21.2–20.7 (5 CH3COЈ, 5 CH3COЈЈ), 19.2, 14.5 (C-6AЈЈ
,
C-6BЈЈ), 17.3, 14.4 (C-6AЈ, C-6BЈ) ppm. MS (MALDI-TOF): calcd.
for C32H44O16 [M]+ 684.26; found 706.80 [M + Na]+. C32H44O16
(684.68): calcd. C 56.13, H 6.48; found C 56.00, H 6.32.
Acetyl 2,3,4-Tri-O-acetyl-α-
L-rhamnopyranosyl-(1Ǟ3)-2,4-di-O-
benzyl-
L
-fucopyranoside (35): 1H NMR (300 MHz, CDCl3) (α-an-
omer): δ = 7.42–7.32 (m, 10 H, Ar-H), 6.44 (d, J1,2 = 2.7 Hz, 1 H,
1A-H), 5.41 (dd, J5,4 = 9.9, J5,6 = 3.6 Hz, 1 H, 3B-H), 5.20 (dd, J2,3
= 3.6, J2,1 = 1.8 Hz, 1 H, 2B-H), 5.06 (t, J4,3 = J4,5 = 9.9 Hz, 1 H,
4B-H), 5.00 (s, 1 H, 1B-H), 4.93 (d, Jgem = 11.1 Hz, 1 H, OCHHPh),
4.71 (d, Jgem = 11.4 Hz, 1 H, OCHHPh), 4.62 (d, Jgem = 11.4 Hz,
1 H, OCHHPh), 4.60 (d, Jgem = 11.1 Hz, 1 H, OCHHPh), 4.18 (dq,
J5,4 = 9.9, J5,6 = 6.3 Hz, 1 H, 5B-H), 4.12 (d, J4,3 = 2.4 Hz, 1 H,
4A-H), 3.99 (q, J5,6 = 6.6 Hz, 1 H, 5A-H), 3.69–3.61 (m, 2 H, 2A-
H, 3A-H), 2.16, 2.11, 2.03, 2.00 (4 s, 12 H, 4 CH3CO), 1.18 (d, J6,5
= 6.6 Hz, 3 H, 6A-H), 0.98 (d, J6,5 = 6.3 Hz, 3 H, 6B-H) ppm. 13C
NMR (CDCl3, 75 MHz) (α anomer): δ = 170.3, 169.9, 169.7, 169.3
(4 CO), 137.9, 137.7 (2 Cipso-Bn), 128.9–127.7 (C-Ar), 94.1 (C-1B),
90.6 (C-1A), 76.1, 75.6, 74.3, 73.4, 73.0, 70.9, 70.3, 69.0, 68.9, 66.5
(C-2A, C-2B, C-3A, C-3B, C-4A, C-4B, C-5A, C-5B, 2 OCH2Ph),
21.0–20.7 (4 CH3CO), 17.0, 16.8 (C-6A, C-6B) ppm. MS (MALDI-
TOF): calcd. for C34H42O13 [M]+ 658.26; found 680.88 [M +
Na]+. C34H42O13 (658.69): calcd. C 62.00, H 6.43; found C 62.18,
H 6.61.
Acetyl 2,3,4-Tri-O-acetyl-α-
L-rhamnopyranosyl-(1Ǟ3)-4-O-allyl-2-
O-benzyl-α- -rhamnopyranoside (33): [α]D = –32 (c = 0.9, CH2Cl2).
L
1H NMR (200 MHz, CDCl3): δ = 7.39 (m, 5 H, Ar-H), 6.15 (d,
J1,2 = 2.0 Hz, 1 H, 1A-H), 5.89 (m, 1 H, OCH2CH=CH2), 5.34–
5.03 (m, 6 H, 1B-H, 2B-H, 3B-H, 4B-H, OCH2CH=CH2), 4.82 (d,
Jgem = 12.0 Hz, 1 H, OCHHPh), 4.62 (d, Jgem = 12.0 Hz, 1 H,
OCHHP h ), 4 . 30 ( dd , J g e m = 1 2 . 8 , J v i c = 5.6 Hz, 1 H,
OCHHCH=CH2), 4.16 (dd, Jgem = 12.8, Jvic = 5.6 Hz, 1 H,
OCHHCH=CH2), 3.95 (dd, J3,4 = 9.4, J3,2 = 3.2 Hz, 1 H, 3A-H),
3.79–3.67 (m, 3 H, 2A-H, 5A-H, 5B-H), 3.54 (t, J4,3 = J4,5 = 9.4 Hz,
1 H, 4A-H), 2.13, 2.08, 2.04, 2.00 (4 s, 12 H, 4 CH3CO), 1.31 (d,
J6,5 = 6.2 Hz, 3 H, 6A-H), 1.07 (d, J6,5 = 6.2 Hz, 3 H, 6B-H) ppm.
Acetyl 2,3,4-Tri-O-acetyl-α-
L-rhamnopyranosyl-(1Ǟ3)-2,4-di-O-
1
benzyl- -quinovopyranoside (36): H NMR (400 MHz, CDCl3) (α-
D
anomer): δ = 7.34–7.24 (m, 10 H, Ar-H), 6.25 (d, J1,2 = 3.6 Hz, 1
H, 1A-H), 5.39–5.28 (m, 3 H, 1B-H, 2B-H, 3B-H), 4.99 (t, J4,3 = J4,5
= 9.9 Hz, 1 H, 4B-H), 4.86 (d, Jgem = 11.1 Hz, 1 H, OCHHPh),
4.72 (d, Jgem = 11.1 Hz, 1 H, OCHHPh), 4.63 (d, Jgem = 11.1 Hz,
1 H, OCHHPh), 4.50 (d, Jgem = 11.1 Hz, 1 H, OCHHPh), 4.10 (t,
J3,4 = J3,2 = 9.6 Hz, 1 H, 3A-H), 4.05 (dq, J5,4 = 9.9, J5,6 = 6.3 Hz,
1 H, 5B-H), 3.91 (dq, J5,4 = 9.6, J5,6 = 6.3 Hz, 1 H, 5A-H), 3.66
13C NMR (CDCl3, 75 MHz): δ = 169.8–169.7 (4 CO), 137.5 (Cipso
-
Bn), 134.4 (OCH2CH=CH2), 128.5–127.7 (C-Ar), 117.2
(OCH2CH=CH2), 99.5 (C-1B), 91.2 (C-1A), 79.7, 78.4, 77.2, 74.4,
72.3, 71.0, 70.9, 69.9, 69.0, 66.9 (C-2A, C-2B, C-3A, C-3B, C-4A, C-
4B, C-5A, C-5B, OCH2Ph, OCH2CH=CH2), 20.8–20.7 (4 CH3CO),
18.0, 17.5 (C-6A, C-6B) ppm. MS (MALDI-TOF): calcd. for
C30H40O13 [M]+ 608.25; found 631.11 [M + Na]+. C30H40O13
(608.63): calcd. C 59.20, H 6.62; found C 59.02, H 6.54.
(dd, J2,3 = 9.6, J2,1 = 3.3 Hz, 1 H, 2A-H), 3.17 (t, J4,3 = J4,5
=
9.6 Hz, 1 H, 4A-H), 2.13, 2.07, 2.01, 1.94 (4 s, 12 H, 4 CH3CO),
1.32 (d, J6,5 = 6.3 Hz, 3 H, 6A-H), 0.91 (d, J6,5 = 6.3 Hz, 3 H, 6B-
H) ppm. 13C NMR (CDCl3, 75 MHz) (α-anomer): δ = 170.0, 169.8,
169.7, 169.4 (4 CO), 137.6, 136.9 (2 Cipso-Bn), 128.9–127.3 (C-Ar),
97.6 (C-1B), 89.0 (C-1A), 81.9, 79.8, 75.4, 75.0, 72.8, 71.0, 69.6,
2,3,4-Tri-O-acetyl-α-
L-rhamnopyranosyl-(1Ǟ3)-1,4,5-tri-O-acetyl-
2-O-benzyl-1-O-methyl-
D
-rhamnose Acetal (34): 1H NMR
(500 MHz, CDCl3): δ = 7.41–7.33 (m, 5 HЈ + 5 HЈЈ, Ar-H), 6.00 (d,
J1,2 = 5.0 Hz, 1 HЈЈ, 1AЈЈ-H), 5.98 (d, J1,2 = 6.0 Hz, 1 HЈ, 1AЈ-H),
5.45 (m, 1 HЈ + 1 HЈЈ, 4AЈ-H, 4AЈЈ-H), 5.25 (m, 1 HЈ + 1 HЈ, 3BЈ- 69.5, 69.2, 66.4 (C-2A, C-2B, C-3A, C-3B, C-4A, C-4B, C-5A, C-5B,
H, 3BЈЈ-H), 5.15 (dd, J2,3 = 3.0, J2,1 = 1.8 Hz, 1 HЈЈ, 2BЈЈ-H), 5.13 2 OCH2Ph), 21.0–20.8 (4 CH3CO), 18.0, 17.1 (C-6A, C-6B) ppm.
Eur. J. Org. Chem. 2008, 5704–5714
© 2008 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
5713

L. Cirillo, E. Bedini, M. Parrilli
FULL PAPER
MS (MALDI-TOF): calcd. for C34H42O13 [M]+ 658.26; found
681.15 [M + Na]+. C34H42O13 (658.69): calcd. C 62.00, H 6.43;
found C 62.20, H 6.56.
H. Lönnberg, J. Szafranek, Carbohydr. Res. 1995, 279, 107–116;
g) M. Miljkovic´, D. Yeagley, P. Deslongchamps, Y. L. Dory, J.
Org. Chem. 1997, 62, 7597–7604; h) J. Kaczmarek, Z. Kaczyn´-
ski, Z. Trumpakaj, J. Szafranek, M. Bogalecka, H. Lönnberg,
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2,3,4-Tri-O-acetyl-α-
L-rhamnopyranosyl-(1Ǟ3)-1,1,4,5-tetra-O-ace-
[3] P. Angibeaud, C. Bosso, J.-P. Utille, Carbohydr. Res. 1990, 198,
403–407.
tyl-2-O-benzyl- -quinovose Acetal (37): [α]D = –15 (c = 0.1,
D
1
CH2Cl2). H NMR (400 MHz, CDCl3): δ = 7.36 (m, 5 H, Ar-H),
6.95 (d, J1,2 = 3.2 Hz, 1 H, 1A-H), 5.33 (s, J4,3 = 2.3 Hz, 1 H, 4A-
H), 5.28 (dd, J3,4 = 10.0, J3,2 = 4.8 Hz, 1 H, 3B-H), 5.19 (dd, J2,3
= 4.8, J2,1 = 3.2 Hz, 1 H, 2B-H), 5.11 (q, J5,6 = 6.3 Hz, 1 H, 5A-
H), 5.06 (t, J4,3 = J4,5 = 10.0 Hz, 1 H, 4B-H), 5.03 (br. s, 1 H, 1B-H),
4.75 (d, Jgem = 11.6 Hz, 1 H, OCHHPh), 4.70 (d, Jgem = 11.5 Hz, 1
H, OCHHPh), 4.06 (dd, J3,2 = 6.8, J3,4 = 2.3 Hz, 1 H, 3A-H), 4.00
(dq, J5,4 = 10.0, J5,6 = 6.4 Hz, 1 H, 5B-H), 3.80 (dd, J2,3 = 6.8, J2,1
= 3.2 Hz, 1 H, 2A-H), 2.10, 2.07, 2.06, 2.05, 2.04, 2.03, 1.97 (7 s,
21 H, 7 CH3CO), 1.24 (d, J6,5 = 6.3 Hz, 3 H, 6A-H), 1.21 (d, J6,5
= 6.4 Hz, 3 H, 6B-H) ppm. 13C NMR (CDCl3, 100 MHz): δ =
[4] L.-X. Wang, Y. C. Lee, J. Chem. Soc. Perkin Trans. 1 1996,
581–591.
[5] a) A. Banaszek, Z. Ciunik, Tetrahedron Lett. 1997, 38, 273–
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[6] P.-E. Jansson in Endotoxin in Health and Disease (Eds.: H.
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[9] For some recent examples, see: a) R. Velty, T. Benvegnu, M.
Gelin, E. Privat, D. Plusquellec, Carbohydr. Res. 1997, 299, 7–
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6252–6260; d) B. D. Johnston, B. M. Pinto, Carbohydr. Res.
1998, 305, 289–292; e) C. Marino, A. Chiocconi, O. Varela,
R. M. de Lederkremer, Carbohydr. Res. 1998, 311, 183–189; f)
A. Chiocconi, C. Marino, R. M. de Lederkremer, Carbohydr.
Res. 2000, 323, 7–13; g) H. Wang, G. Zhang, J. Ning, Car-
bohydr. Res. 2003, 338, 1033–1037; h) M. Gelin, V. Ferrières,
M. Lefeuvre, D. Plusquellec, Eur. J. Org. Chem. 2003, 1285–
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2006, 8, 3971–3974; j) Y. Bai, T. L. Lowary, J. Org. Chem. 2006,
71, 9658–9671; k) C. Mukherjee, A. Kumar Misra, Synthesis
2007, 683–692; l) M. Joe, Y. Bai, R. C. Nacario, T. L. Lowary,
J. Am. Chem. Soc. 2007, 129, 9885–9901; m) K. Naresh, B. K.
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170.1, 170.0, 169.9, 169.7, 168.6, 168.5, 168.4 (7 CO), 134.7 (Cipso
-
Bn), 128.4–127.9 (C-Ar), 100.8, 98.9 (C-1A, C-1B), 87.7, 74.5, 74.1,
72.9, 70.9, 69.6, 69.0, 68.8, 67.5 (C-2A, C-2B, C-3A, C-3B, C-4A, C-
4B, C-5A, C-5B, OCH2Ph), 21.1–20.7 (7 CH3CO), 17.3, 15.8 (C-6A,
C-6B) ppm. MS (MALDI-TOF): calcd. for C33H44O17 [M]+ 712.29;
found 734.61 [M + Na]+. C33H44O17 (712.69): calcd. C 55.61, H
6.22; found C 55.42, H 6.10.
Acetyl 2,3,4-Tri-O-acetyl-α-
L-rhamnopyranosyl-(1Ǟ3)-5-O-acetyl-
1
2-O-benzyl- -quinovofuranoside (38): H NMR (300 MHz, CDCl3)
D
(β-anomer): δ = 7.31 (m, 5 H, Ar-H), 6.21 (s, 1 H, 1A-H), 5.25–
5.00 (m, 4 H, 2B-H, 3B-H, 4B-H, 5A-H), 4.76 (s, 1 H, 1B-H), 4.69
(d, Jgem = 11.7 Hz, 1 H, OCHHPh), 4.60 (d, Jgem = 11.7 Hz, 1 H,
OCHHPh), 4.36 (dd, J4,5 = 7.2, J4,3 = 4.5 Hz, 1 H, 4A-H), 4.29 (d,
J3,4 = 4.5 Hz, 1 H, 3A-H), 4.08 (s, 1 H, 2A-H), 3.79 (dq, J5,4 = 9.3,
J5,6 = 6.3 Hz, 1 H, 5B-H), 2.15, 2.09, 2.06, 2.04, 1.98 (5 s, 15 H, 5
CH3CO), 1.38 (d, J6,5 = 6.3 Hz, 3 H, 6A-H), 1.24 (d, J6,5 = 6.3 Hz, 3
H, 6B-H) ppm. 13C NMR (CDCl3, 75 MHz) (β-anomer): δ = 170.1–
169.6 (5 CO), 136.8 (Cipso-Bn), 128.5–127.7 (C-Ar), 99.2 (C-1B),
95.8 (C-1A), 84.2, 83.6, 76.9, 72.4, 70.6, 69.8, 68.9, 68.5, 67.5 (C-
2A, C-2B, C-3A, C-3B, C-4A, C-4B, C-5A, C-5B, OCH2Ph), 21.3–
20.7 (5 CH3CO), 17.6, 17.2 (C-6A, C-6B) ppm. MS (MALDI-TOF):
calcd. for C29H38O14 [M]+ 610.23; found 632.97 [M + Na]+.
C29H38O14 (610.60): calcd. C 57.04, H 6.27; found C 57.00, H 6.24.
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Acknowledgments
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Received: July 14, 2008
Published Online: October 20, 2008
5714
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