Convenient approach to higher carbon sugars. First synthesis of the free C12-sugar: D-erythro-L-manno-D-manno-dodecose

Article abstract of DOI:10.1016/S0008-6215(02)00484-6

The model synthesis of a C12-aldose was initiated from the easily available dimethyl(benzyl 2,3,4-tri-O-benzyl-α-D-manno-heptopyranos-6-ulos-7-yl)phosphonate and 2,3:4,5-di-O-isopropylidene-D-arabinose.

Full text of DOI:10.1016/S0008-6215(02)00484-6

Carbohydrate Research 338 (2003) 407–413
www.elsevier.com/locate/carres
Convenient approach to higher carbon sugars. First synthesis of
the free C12-sugar: -erythro- -manno- -manno-dodecose
D
L
D
Sławomir Jarosz,* Stanisław Sko´ra, Izabela Kos´ciołowska
Institute of Organic Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland
Received 8 August 2002; accepted 28 October 2002
Abstract
The model synthesis of a C12-aldose was initiated from the easily available dimethyl(benzyl 2,3,4-tri-O-benzyl-a-
D-manno-
heptopyranos-6-ulos-7-yl)phosphonate and 2,3:4,5-di-O-isopropylidene- -arabinose. © 2003 Published by Elsevier Science Ltd.
D
way, however, consists of coupling of two suitable
activated monosaccharide subunits.9
Monosaccharides, containing more than 10 carbon
atoms in the chain can be divided into three main
classes: C-disaccharides (e.g., 11) higher aldoses (e.g.,
22) and higher dialdoses (e.g., 33). Examples of these
three classes are shown in Fig. 1.
Very little is known about higher aldoses. Only lim-
ited examples of such derivatives are reported in the
literature10–14 (very few in a free form), despite the fact
that such complex molecules might be interesting
targets for studying the conformational mobility of
polyhydroxylated compounds. In this paper the synthe-
Higher carbon sugars are interesting molecules, al-
though very few of them can be found in nature. They
can be used as non-metabolized analogues of di- and
oligosaccharides, are interesting targets for developing
new synthetic methodologies and studying the confor-
mational features. The synthesis of compounds of type
1 and 3 is now well explored (especially well docu-
mented are the syntheses of C-glycosides4) and such
derivatives may be prepared without special problems
using different synthetic methods.5 In principle, they
can be prepared by total synthesis,6 by iterative elonga-
tion of simple monosaccharides (pentoses, or hexoses)
with a C1-,7 or C2-units.8 The best and most economic
sis of the free C12-sugar:
D-erythro-L-manno-D-manno-
dodecose will be presented.
In the past several years we elaborated a convenient
methodology for the preparation of higher dialdoses by
coupling of two suitably activated simple sugar sub-
units.15 Especially useful was the reaction of sugar
phosphoranes 416 or better phosphonates 514,17 with
sugar aldehydes providing a higher enone 6, finally
converted into the desired dialdose (Fig. 2).
The key-step in the functionalization of a three-car-
bon atom bridge (connecting the sugar portions of 6) is
Fig. 1. The examples of different types of higher carbon sugars.
* Corresponding author. Tel.: +4822-632-32-21; fax: +4822-632-66-81
E-mail address: sljar@icho.edu.pl (S. Jarosz).
0008-6215/03/$ - see front matter © 2003 Published by Elsevier Science Ltd.
PII: S0008-6215(02)00484-6

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S. Jarosz et al. / Carbohydrate Research 338 (2003) 407–413
Slight modifications of the starting sugar sub-units
should allow preparing a higher sugar aldose, which
might be converted into a free saccharide by removal of
suitable blocking groups. Therefore, one sub-unit
should have the anomeric position blocked with the
group easily removable under neutral conditions and
the other one could be the simple aldose preferable in
an open-chain form.
The model synthesis of a C12-aldose was initiated
from the easily available dimethyl(benzyl 2,3,4-tri-O-
benzyl-a-D-manno-heptopyranos-6-ulos-7-yl)phospho-
nate17 (7) and 2,3:4,5-di-O-isopropylidene-
(8) and is presented in Scheme 1.
D-arabinose
Reaction of both partners 7 and 8 under mild phase
transfer conditions K2CO3, 18-crown-6, toluene, room
temperature)13 afforded the trans-higher sugar enone 9
in 74% yield. Reduction of the carbonyl group with
zinc borohydride gave, as expected18, the R-alcohol 11;
its configuration was verified by chemical degradation
Fig. 2. The synthesis of higher dialdoses from simple sugar
sub-units: phosphoranes (4) or phosphonates (5) and alde-
hydes.
to known19 benzyl 2,3,4-tri-O-benzyl-
D-glycero-a-D-
a stereoselective reduction of the carbonyl group with
manno-heptoside (10; Scheme 1 and Section 2). The
next step required osmylation of the double bond what
would provide the triol with the (7R,8S) configuration
at the newly created chiral centers as predicted by the
zinc borohydride. This reaction performed for the
D-
sugars affords exclusively the allylic alcohols with the
R-configuration at the newly created stereogenic center
(see model in Fig. 2).18
Scheme 1. (i) K2CO3, 18-crown-6, toluene, rt, 74%; (ii) Zn(BH4)2, ether, 0 °C, 94%; (iii) from 11, O3, then NaBH4; (iv) 85%; BnBr,
NaH, DMF, rt; (v) OsO4, NMO, THF, water.

S. Jarosz et al. / Carbohydrate Research 338 (2003) 407–413
409
formation of up to 30% of the b-pyranose during
acetylation of mannose24 and manno-heptoses.25 The
a-configuration at the C-1 was proved by the JC-1–H-1
coupling constant26 which was found to be 178 Hz.
The mixture of two fully acetylated dodecoses was
separated by the HPLC chromatography and the indi-
viduals were identified as the a and b pyranoses 16a
1
and 16b on the basis of their NMR data. The H and
13C NMR spectra of the main isomer were identical
with the corresponding data of 16a obtained from 15.
In the 1H NMR spectrum of the minor isomer the
highest up-field signal at l was assigned to the H-5
proton (COSY), thus proving the pyranose structure of
the product. Further proof of the b-pyranose structure
came from the undecoupled 13C NMR spectrum in
which the coupling constant JC-1–H-1 162 Hz was ob-
served. This compound was also identical with the
minor isomer present as contamination of 16a obtained
from the benzyl glycoside 15. No formation of fura-
noses was detected what is consistent with the literature
data; such peracetylated manno-furanoses are obtained
using special condition.27
Scheme 2. (i) THF, H2O, 10% H2SO4, reflux, 20 h H2/Pd then
Ac2O/Py.
1. Conclusion
Kishi’s rule.20 Confirmation of the configuration at
these two centers in the triol would be rather difficult
(unless the X-ray assignment is possible). However,
since the absolute configuration of the sugar threo-diols
can be easily assigned by the CD spectroscopy,17,21,22
we decided to protect the free hydroxy group in 11 as
benzyl ether prior to oxidation. Osmylation23 of such
protected olefin 12 afforded the diol 13; the positive
Cotton effect in the CD spectrum of the complex of 13
with dimolybdenum tetraacetate [u: 362 (Dm% −0.35),
306.5 (Dm% +0.76) nm] pointed unequivocally at the
(7R,8S) configuration of the newly created stereogenic
centers.
The synthesis of unprotected dodecose was accom-
plished in a few steps from simple monosaccharide
sub-units. The structure of the free sugar as well as its
peracetate is similar to the structure of the parent
hexoses (or heptoses). The statement of Angyal: ‘‘Ex-
tension of the side-chain, on going from hexoses to
heptoses, does not introduce any new steric interaction
into the pyranose or the furanose ring’’28 is also found
for compounds extended by six carbon atoms.
2. Experimental
To finish the synthesis of the free C12-aldose, the
hydroxy groups in 13 were protected as benzyl ethers
(“13a), the isopropylidene groups were removed by
hydrolysis, and the resulting tetraol 14 was subjected to
hydrogenolysis.
Optical rotations were measured with a JASCO DIP
360 automatic polarimeter at 2092 °C. NMR spectra
were recorded with Varian Gemini AC-200 (200 MHz)
or Bruker AM-500 (500 MHz) specrometers in CDCl3
solns with Me4Si as an internal standard unless other-
wise stated. 1H and 13C signal of aromatic groups
occurred at the expected chemical shifts were omitted in
the description of spectra. 13C NMR spectra were
recorded in the DEPT 135 mode. The proton and
carbon resonances in 17 and 18 were assigned by the
COSY and HETCOR correlations. Mass spectra
(LSIMS, positive mode) were recorded on an AMD-
604 mass spectrometer. HPLC was carried out on a
Shimadzu instrument: central unit C-R4A, pump unit
LC-8A, RI detector Shimadzu RiD-6a on a column
Macherey-Nagel AG, Nucleosil 100, 7 m. CD spectrum
of 13 was measured with JASCO 715 CD spectrometer
The product was acetylated and further isolated as
diastereoisomeric mixture of acetates by column chro-
matography. The first product was identified as the
benzyl glycoside of the deca-acetate 15, the second—as
a 3:2 mixture of two undeca-acetates (Scheme 2). For-
tunately, isolation of the benzyl glycoside 15 provided a
unique possibility of obtaining fully acetylated sugar
with the known size of the ring, the pyranose 16. Thus,
removal of the benzyl protecting group with H2/Pd
followed by acetylation afforded the pyranose 16a con-
taminated with the small amounts of other isomer
(assigned as the b-anomer, 16b; see below). This is
consistent with the literature data, which report on

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S. Jarosz et al. / Carbohydrate Research 338 (2003) 407–413
for soln in Me2SO to which the complex Mo2(OAc)4
was added (molar ratio 1.25:1). TLC was performed on
Silica Gel HF-254 ready plates and column chromatog-
raphy on Silica Gel 230–400 or 70–230 mesh (E.
Merck).
(CH2Ph), 71.9 (CH2Ph), 69.1 (CH2Ph), 66.8 (C 12),
27.0, 26.9, 26.6, 25.2 (2×CMe2). Anal. Calcd for
C46H54O10·0.5H2O: C, 71.20; H, 7.15. Found: C, 71.20;
H, 7.04.
2.3. Determination of the configuration at the C-6 cen-
ter in 11
2.1. Benzyl 2,3,4-tri-O-benzyl-7(E)-dideoxy 7(E)-eno-
9,10:11,12-di-O-isopropylidene-6-oxo-
manno-dodeca-1,5 pyranoside (9)
D
-arabino-a-D-
Through a cooled to −78 °C soln of the alcohol 11
(100 mg, 0.13 mmol) in CH2Cl2 (10 mL) and MeOH (5
mL) ozone was bubbled until the blue color persisted
(approx 15 min). Excess of ozone was removed by
bubbling of a stream of oxygen through the solution for
5 min. Sodium borohydride (20 mg) was added, the
mixture was stirred 1 h at rt and the desired heptoside
10 (50 mg) was isolated by column chromatography
(C6H14–EtOAc 3:1“2:1). It was identical in all respect
with the synthetic material prepared independently.19
To a soln of dimethyl(benzyl 2,3,4-tri-O-benzyl-a-
manno-heptopyranos-6-ulos-7-yl)phosphonate17 (7; 4.5
g, 6.7 mmol) and 2,3:4,5-di-O-isopropylidene- -ara-
D-
D
binose (8; 1.8 g, 7.8 mmol) in dry C6H5CH3 (100 mL),
solid potassium carbonate (3 g) was added followed by
18-crown-6 (50 mg) and the mixture was stirred for 24
h at room temperature (rt). After this time TLC (1:1
C6H14–EtOAc) showed disappearance of both starting
materials and formation of a new, less polar product
that was visible in the UV light. Water (80 mL) and
ether (80 mL) were added, the organic phase was
separated, washed with water, dried and concentrated,
and the residue was chromatographed with C6H14–
EtOAc (3:1“2:1) to afford enone 9 (3.8 g, 4.97 mmol,
2.4. Benzyl 2,3,4,6-tetra-O-benzyl-7,8-dideoxy 7(E)-
eno-9,10:11,12-di-O-isopropylidene-
D
-gluco-a- -manno-
D
dodeca-1,5-pyranoside (12)
To a soln of alcohol 11 (3.25 g, 4.24 mmol) in DMF (20
mL), sodium hydride (50% dispersion in mineral oil;
300 mg) was added carefully and the mixture was
stirred for 15 min at rt. Benzyl bromide (0.6 mL, 5.0
mmol) was added dropwise during 5 min and the
mixture was stirred for another 30 min. Excess of
hydride was decomposed by careful addition of water,
the mixture was partitioned between ether (50 mL) and
brine (30 mL), the organic phase was separated, washed
with water (20 mL), dried, concentrated, and the
residue was chromatographed with C6H14–EtOAc
(3:1“2:1) to afford 12 (3.1 g, 3.62 mmol, 85%) as an
oil. This product was used directly for the next step.
1
74%) as an oil. [h]D +23.3° (c 1.0, CHCl3); H NMR
(200 MHz) inter alia l: 7.05 (dd, 1 H, J7,8 4.6, J8,9 15.7
Hz, H-8), 6.80 (dd, 1 H, J7,9 1.2 Hz, H-7), 5.00 (d, 1 H,
J1,2 2.2 Hz, H-1), 1.41, 1.36 (×2); 13C NMR l: 194.8
(CꢀO), 144.2 (C-8), 126.1 (C-7), 110.1, 109.7 (2×
CMe2), 97.6 (C-1), 81.1, 79.1 (×2), 76.8, 75.7, 75.5,
74.8 (CH2Ph), 74.5, 72.7 (CH2Ph), 72.3 (CH2Ph), 69.5
(CH2Ph), 67.3 (C-12), 26.9, 26.7 (×2), 25.2 (2×
CMe2). Anal. Calcd for C46H52O10·0.5H2O: C, 71.39; H,
6.90. Found: C, 71.74; H, 6.62.
2.2. Benzyl 2,3,4-tri-O-benzyl-7,8-dideoxy 7(E)-eno-
9,10:11,12-di-O-isopropylidene-
deca-1,5 pyranoside (11)
D
-gluco-a- -manno-do-
D
2.5. Benzyl 2,3,4,6-tetra-O-benzyl-9,10:11,12-di-O-iso-
propylidene-D-erythro-
L
-manno-a- -manno-dodeca-1,5-
D
Enone 9 (3.6 g, 4.69 mmol) was dissolved in dry ether
(50 mL) and cooled to 0 °C. Zinc borohydride (10 mL
of a approx 0.5 M soln in ether) was added and the
mixture was stirred for 30 min at 0 °C. The excess of
borohydride was decomposed by careful addition of
water (5 mL), the mixture was partitioned between
ether (50 mL) and brine (50 mL), the organic layer was
separated washed with diluted H2SO4, brine (to neutral-
ity) dried concentrated, and the residue was chro-
matographed with C6H14–EtOAc (2:1“1:1) to afford
alcohol 11 (3.4 g, 4.43 mmol, 94%) as an oil. [h]D
pyranoside (13)
To a soln of 12 (3.0 g, 3.5 mmol) in THF (20 mL),
tert-butyl alcohol (1.5 mL) and water (1.0 mL), N-
methylmorpholine N-oxide (580 mg, 4.3 mmol) was
added followed by osmium tetraoxide (0.8 mL of a
approx 2% soln in C6H5CH3). The mixture was stirred
for 24 h (TLC monitoring in C6H14–EtOAc 2:1), then
diluted with MeOH (30 mL), and aq 40% sodium
hydrogensulphite was added. The mixture was stirred
for 30 min, filtered through Celite, concentrated, and
partitioned between water (50 mL) and ether (50 mL).
Organic phase was separated, dried, concentrated, and
the residue was chromatographed with C6H14–EtOAc
(2:1“1:1) to afford 13 (2.4 g, 2.69 mmol, 77%) as the
only product as an oil. 13C NMR l: 109.9, 109.4
(2×CMe2), 97.0 (C-1), 80.7, 80.6, 79.6, 78.2, 76.5, 75.4,
1
+38.1° (c 1.1, CHC13); H NMR (200 MHz) inter alia
l: 6.05 and 5.85 (dd, 1 H, J 6.2, J8,9 16.2 Hz, dd, 1 H,
J 5.9 Hz, H-7,8),4.92 (d, 1 H, J1,2 1.8 Hz, H-1), 1.37,
(×3), 1.28 (2×CMe2); 13C NMR l: 194.8 (CꢀO),
131.1, 130.0 (C-7,8), 109.5, 109.2 (2×CMe2), 97.1 (C-
1), 81.0, 80.2, 79.6, 76.6, 76.0, 74.6 (CH2Ph), 73.9, 72.1

S. Jarosz et al. / Carbohydrate Research 338 (2003) 407–413
411
75.0 (CH2Ph), 74.8, 73.0 (CH2Ph), 72.8 (CH2Ph), 72.6,
71.2, 70.0, 68.8 (CH2Ph), 67.4 (C-12), 27.1 (×2), 26.4,
25.2 (2×CMe2). CD [u (Do%)]: 362 (−0.35), 306.5
(+0.76) nm.
ford benzyl glycoside 15 (230 mg, 0.26 mmol, 26%) and
fully acetylated derivative 16 (450 mg, 0.55 mmol, 55%)
as a 3:2 mixture of a and b pyranoses as judged from
the integration of the 1H NMR resonances at l
(CHCl3): 6.05 (d, 1 H, J1,2 2.6 Hz, H-1a) and 5.95 (d, 1
H, J1,2 2.0 Hz, H-1a). The a or b configuration of these
derivatives was proved by the coupling constant JC-1–H-
1 which was assigned as 178 and 162 Hz, respectively.
The mixture of a and b pyranoses (16) was separated
by HPLC. The 2D spectra allow to assign precisely the
pyranose structure for both isomers (see below). Benzyl
glycoside 15 was hydrogenated over Pd/C and then
acetylated to give predominantly a pyranose 16a con-
taminated with small amounts of the b-pyranose (ratio
16a:16b=10:1).
2.6. Benzyl 2,3,4,6,7,8-hexa-O-benzyl-9,10:11,12-di-O-
isopropylidene-D-erythro-
L
-manno-a- -manno-dodeca-
D
1,5-pyranoside (13a)
This product was obtained (analogously to 12) from 13
in 75% yield [h]D +21.3° (c 1.3, CHCl3); 13C NMR l:
109.7, 109.4 (2×CMe2), 96.9 (C 1), 80.9, 80.3, 79.6,
78.9, 78.5, 76.7, 76.0, 75.3, 74.9, 74.5 (CH2Ph), 74.1
(CH2Ph), 74.0 (CH2Ph), 72.9 (CH2Ph), 72.4 (CH2Ph),
72.1 (CH2Ph), 71.4, 68.5 (CH2Ph), 65.1 (C-12), 27.5,
27.4, 26.3, 25.3 (2×CMe2). Anal. Calcd for C67H74O12:
C, 75.11; H, 6.96. Found: C, 75.06; H, 7.00.
2.9. Benzyl 1,2,3,4,6,7,8,9,10,11,12-deca-O-acetyl-
D-
erythro- -manno-a- -manno-dodeca-1,5-pyranoside (15)
L
D
2.7. Benzyl-2,3,4,6,7,8-hexa-O-benzyl-
D-erythro-L-
manno-a- -manno-dodeca-1,5-pyranoside (14)
D
[h]D +35.6° (c 1.0, CHCl3); 1H NMR (500 MHz,
COSY, CDCl3) l: 7.30 (m, 5 H, CH2Ph), 5.50 (dd, 1 H,
J7,8 9.2, J8,9 2.1 Hz, H-8), 5.41 (dd, 1 H, J6,7 2.0 Hz,
H-7), 5.36 (dd, 1 H, J9,10 6.7 Hz, H-9), 5.31 (dd, 1 H,
J2,3 3.02, J3,4 9.4 Hz, H-3), 5.29–5.27 (m, 2 H, H-6,10),
5.21 (dd, 1 H, J1,2 2.0 Hz, H-2), 5.20 (dd, 1 H, J5,6 9.6
Hz, H-4), 5.01 (ddd, 1 H, J10,12 ꢀ6, J10,12% 3.0, J10,12¦ 5.4
Hz, H-11), 4.79 and 4.55 (AB of CH2Ph), 4.23 (dd, 1 H,
J12%,12¦ 12.4 Hz, H-12%), 4.15 (dd, 1 H, J5,6 4.2 Hz, H-5),
4.02 (dd, H-12¦), 2.12, 2.09, 2.07, 2.06, 2.05, 2.042,
2.038, 2.02, 2.00, 197 (30 H, 10×OAc); 13C NMR (125
MHz, CDCl3, HETCOR) l: 170.5, 169.91, 169.87,
169.79, 169.73, 169.6, 169.50, 169.48, 169.28, 169.24
(10×CH3CO), 136.2 (quat. CH2Ph), 128.6 (×2),
128.2, 127.7 (×2), 96.1 (C-1), 69.9 (C 10), 69.7 (C-5),
69.5 (C-2), 69.4 (C-3), 69.3 (CH2Ph), 68.5 (C-11), 67.7
(C-6), 67.6 (C-9), 67.5 (C-8), 67.3 (C-4), 67.2 (C-7), 61.9
(C-12), 20.9, 20.78 (×3), 20.75, 20.71, 20.68, 20.64
(×3). 13C NMR (125 MHz, CDCl3, undecoupled):
JC-1–H-1 174.3 Hz. HR MS (LSIMS) m/z Calcd for
C39H50O22Na: 893.2681. Found: 893.2660.
To a soln of 13a (2.0 g, 1.87 mmol) in THF (20 mL)
and water (3 mL) a 10% soln of H2SO4 (1 mL) was
added and the mixture was kept at rt overnight. Small
amount of the mixture was worked-up as usual (approx
1 mL) and the product was analyzed by 13C NMR
spectroscopy. Only one isopropylidene group was seen
what suggested partial hydrolysis of the C11–C12 iso-
propylidene grouping. 13C NMR l: 109.3 (CMe2), 96.9
(C-1), 80.9, 80.7, 80.0, 79.1, 78.2, 77.7, 75.2, 74.8, 74.5
(CH2Ph), 74.2 (CH2Ph), 72.9 (2×CH2Ph), 72.3
(CH2Ph), 72.0 (CH2Ph), 71.3, 68.6 (CH2Ph), 63.5 (C-
12), 26.9, 26.7 (CMe2). The rest of the mixture was
boiled under reflux for 20 h and after cooling to rt
partitioned between EtOAc (50 mL) and brine (20 mL).
The organic layer was separated washed with water to
neutrality, dried, concentrated and the residue was
chromatographed with C6H14–EtOAc (1:1“1:3) to af-
ford 15 (1.57 g, 1.59 mmol, 85%) as a foam. 13C NMR
l: 109.7, 109.4 (2×CMe2), 97.0 (C-1), 80.8, 79.0, 78.5,
77.5, 75.2, 75.1, 74.5 (CH2Ph), 74.0 (2×CH2Ph), 73.1,
72.9 (CH2Ph), 72.6 (CH2Ph), 72.1 (CH2Ph), 71.5, 70.1,
69.9, 68.5, (CH2Ph), 63.7 (C-12). Anal. Calcd for
C61H66O12·2.5H2O: C, 70.70; H, 6.91. Found: C, 70.76;
H, 7.20.
2.10. 1,2,3,4,6,7,8,9,10,11,12-Undeca-O-acetyl-
D
-ery-
thro- -manno-a-
L
D
-manno-dodeca-1,5-pyranose (16a)†
1H NMR (500 MHz, CDCl3, COSY) l: 6.03 (d, 1 H,
J1,2 2.7 Hz, H-1), 5.43 (dd, 1 H, J 1.9 and 9.5 Hz, H-9),
5.40 (dd, 1 H, J5,6 6.2, J6,7 5.8 Hz, H-6), 5.30 (2 H,
H-8,10), 5.29 (dd, 1 H, J2,3 3.4, J3,4 9.7 Hz, H-3), 5.19
(3 H, H-2,4,7), 4.99 (ddd, 1 H, J10,11 8.3, J11,12% 2.9,
J11,12¦ 5.3 Hz, H-11), 4.21 (dd, 1 H, J12%,12¦ 12.5 Hz,
H-12%), 4.19 (dd, 1 H, J4,5 9.2 Hz, H-5), 4.02 (dd, 1 H,
2.8. Hydrogenolysis of the protected pyranose 14
A soln of the tetraol 14 (990 mg, 1.0 mmol) in MeOH
(10 mL) and EtOAc (10 mL) was hydrogenated over
10% Pd/C (20 mg) for 24 h. The solution was filtered,
through Celite, concentrated and the residue dissolved
in Py (15 mL) to which Ac2O (10 mL) was added
followed by catalytic amount of DMAP (20 mg). The
mixture was kept at rt overnight, concd and the residue
was chromatographed with C6H14–EtOAc (2:1) to af-
1
H-12¦); H NMR (500 MHz, C6D6, COSY) l: 6.41(?)
(d, 1 H, J1,2 2.8 Hz, H-1), 6.01 (dd, 1 H, J5,6 6.0, J6,7 5.7
† Compound 16a was contaminated with ca. 5% of the
isomer 16b and vice versa.

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S. Jarosz et al. / Carbohydrate Research 338 (2003) 407–413
For more recent papers, see: (b) Marquis, Ch.; Picasso,
S.; Vogel, P. Synthesis 1999, 1441–1452;
(c) Blackwell, H. E.; O’Leary, D. J.; Chatterjee, A. K.;
Washenfelder, R. C.; Bussmann, D. A.; Grubbs, R. H. J.
Am. Chem. Soc. 2000, 122, 58–71;
Hz, H-6), 5.99 (dd, 1 H, J8,9 9.8, J9,10 1.9 Hz, H-9), 5.88
(dd, 1 H, J7,8 1.7 Hz, H-8), 5.82 (dd, 1 H, H-7), 5.79
(dd, 1 H, J2,3 2.9, J3,4 8.6 Hz, H-3), 5.78 (dd, 1 H, J10,11
8.4 Hz, H-10), 5.74 (dd, 1 H, J4,5 8.6 Hz, H-4), 5.57 (dd,
1 H, H-2), 5.40 (ddd, 1 H, J11,12% 2.9, J11,12¦ 5.2 Hz,
H-11), 4.66 (dd, 1 H, H-5), 4.55 (dd, 1 H, J12%,12¦ 12.5
Hz, H-12%), 4.26 (dd, 1 H, H-12¦); 13C NMR (125 MHz,
CDCl3, HETCOR) l: 170.5, 170.0, 169.9 (×2), 169.83,
169.81, 169.7, 169.5, 169.2, 169.0, 168.3 (11×CH3CO),
89.9 (C-1), 70.8 (C 5), 70.5 (C-6), 69.4, 68.4 (C-11), 68.5
(C-11), 68.0, 67.4, 67.1, 67.3, 66.9, 66.7 (C-9), 61.8 (C
12), 21.0, 20.9, 20.79, 20.78, 20.75 (×2), 20.7, 20.64
(×2), 20.58). 13C NMR (125 MHz, CDCl3, undecou-
pled): JC-1–H-1 178 Hz. HR MS (LSIMS) m/z Calcd for
C34H46O23Na: 845.2322. Found: 845.2354.
(d) Maria, E. J.; da Silva, A. D.; Fourrey, J.-L. Eur. J.
Org. Chem. 2000, 627–631 and references cited therein.
6. Danishefsky, S. J.; Mating, C. J.; DeNinno, M. P. Angew.
Chem., Int. Ed. Engl. 1987, 26, 15–23.
7. Dondoni, A. In Modern Synthetic Methods; Scheffold,
R., Ed.; Verlag Helvetica Chimica Acta: Basel, 1992; pp
377–438.
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Vol. 4C, pp 157–193.
9. (a) Horton, D.; Tsai, J.-H. Carbohydr. Res. 1979, 75,
151–174;
(b) Jarosz, S. J. Carbohydr. Chem. 1993, 12, 1149–1160.
10. (a) Paulsen, H.; Roden, K.; Sinvell, V.; Koebernick, W.
Angew. Chem. 1976, 88, 477;
(b) Paulsen, H.; Schu¨ller, M.; Heitmann, A.; Nashed, M.
A.; Redlich, H. Justus Liebigs Ann. Chem. 1986, 675–686.
11. For C-10 aldoses, see: (a) Brimacombe, J. S.; Hanna, R.;
Kabir, A. K. M. S. J Chem. Soc., Perkin Trans. 1 1986,
823–828;
2.11. 1,2,3,4,6,7,8,9,10,11,12-Undeca-O-acetyl-
D-ery-
thro- -manno-b- -manno-dodeca-1,5-pyranose (16b)
L
D
1H NMR (500 MHz, COSY, C6D6) l: 6.06 (dd, 1 H,
J5,6 7.0, J6,7 5.5 Hz, H 6), 5.98–5.93 (m, 3 H, J1,2 2.3
Hz, H 1, H 8,9), 5.77 (dd, 1 H, J9,10 1.7, J10,11 8.7 Hz,
H 10), 5.64–5.61 (m, 2 H, H 2.7), 5.58 (t, J3,4=J4,5 7.6
Hz, H 4), 5.43 (ddd, J11,12% 3.0, J11,12¦ 5.5 Hz, H 11),
5.33 (dd, 1 H, J2,3 3.2 Hz, H 3), 4.55 (dd, 1 H, J12%,12¦
12.5 Hz, H 12%), 4.38 (t, 1 H, H 6), 4.22 (dd, 1 H, H
12¦), 2.09, 2.06, 2.03, 1.98, 1.95, 1.93, 1.92, 1.91, 1.88,
1.83, 1.78 (30 H, 11×OAc). 13C NMR (125 MHz,
CDCl3, undecoupled): JC-1–H-1 162 Hz. HR MS
(LSIMS) m/z Calcd for C34H46O23Na: 845.2322.
Found: 845.2343.
(b) Brimacombe, J. S.; Kabir, A. K. M. S. Carbohydr.
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(c) Brimacombe, J. S.; Hanna, R.; Roderick, Kabir, A.
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Am. Chem. Soc. 1985, 107, 7762–7764;
(b) Danishefsky, S.; Maring, C. J. Am. Chem. Soc. 1989,
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(c) Ikemoto, N.; Schreiber, S. L. J. Am. Chem. Soc. 1990,
112, 9657–9659;
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114, 2524–2536;
(e) Marshall, J. A.; Beaudoin, S. J. Org. Chem. 1994, 59,
6614–6619.
13. For C-12 aldoses, see: (a) Jarosz, S. Tetrahedron Lett.
1994, 35, 7655–7658;
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