Synthesis of higher carbon sugars. Unexpected rearrangement of higher sugar allylic alcohols

Article abstract of DOI:10.1016/j.tetasy.2008.05.010

Coupling of a sugar phosphonate with a sugar aldehyde afforded a C₁₃-higher sugar enone. Reduction of the carbonyl function provided both stereoisomeric allylic alcohols. Inversion of the configuration at the carbinol centre in these derivatives did not yield the expected S_N2 product, but proceeded with rearrangement to the tetrahydrofuran derivative.

Full text of DOI:10.1016/j.tetasy.2008.05.010

Tetrahedron: Asymmetry 19 (2008) 1385–1391
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Tetrahedron: Asymmetry
journal homepage: www.elsevier.com/locate/tetasy
Synthesis of higher carbon sugars. Unexpected rearrangement of higher
sugar allylic alcohols
*
Slawomir Jarosz , Agnieszka Gajewska, Roman Luboradzki
Institute of Organic Chemistry, Polish Academy of Sciences, Kasprzaka, 44, 01-224 Warszawa, Warsaw, Poland
Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka, 44, 01-224 Warszawa, Warsaw, Poland
a r t i c l e i n f o
a b s t r a c t
Article history:
Coupling of a sugar phosphonate with a sugar aldehyde afforded a C13-higher sugar enone. Reduction of
the carbonyl function provided both stereoisomeric allylic alcohols. Inversion of the configuration at the
carbinol centre in these derivatives did not yield the expected SN2 product, but proceeded with rear-
rangement to the tetrahydrofuran derivative.
Received 29 April 2008
Accepted 14 May 2008
Available online 9 June 2008
Ó 2008 Published by Elsevier Ltd.
1. Introduction
activation
(C)n
Higher carbon sugars containing more than 10 carbon atoms in
the chain are interesting synthetic targets. While the role of hep-
toses, octoses and nonoses in the biology of living cells is well doc-
umented and many synthetic methods have been developed to
prepare these important compounds,1 the longer analogues such
as tunicamine2 or hikozamine3 (being components of antibiotics)
are scarce in Nature. The synthesis of such demanding targets
can be realized either by iterative C1 or C2 elongation4 (which is
a tedious and lengthy procedure) or by coupling of a sugar with
a Cn unit. This fragment may be represented by an achiral unit
(such as highly activated dienes, which upon reaction with
sugar-derived aldehydes affords precursors of these targets5) or
more conveniently by an already functionalized unit.
Two different classes of higher carbon sugars may be regarded.
The first represents so-called C-glycosides, which possess a car-
bon–carbon bond at the anomeric position. Such derivatives are
well known and many methods have been developed for their
preparation.6
We are interested in another class of higher carbon sugars in
which the C–C bond is created between the non-anomeric carbon
atoms; especially those which are connected via terminal carbon
atoms. The strategy involves reaction of properly activated sugar
sub-units, which are coupled either directly or via additional C-
atom(s) (Fig. 1).
OH
O
OH
O
n = 0,1,2
Sug1
Sug2
R
R
O
O
Sug1
Sug2
Figure 1. Synthesis of higher sugars by coupling of two properly activated sub-
units.
could either react with a sugar aldehyde (R0-CHO) affording a de-
sired higher sugar precursor 3, or decompose via a b-elimination
process (Fig. 2).
To overcome the problem of decomposition of the phosphorane,
we have introduced the stabilized Wittig reagents such as 4 and
more conveniently the phosphonates 5 (Fig. 3).8
Both reactive intermediates were applied in the preparation of a
skeleton of higher carbon sugar 6, in which the allylic bridge
flanked by two sugar sub-units is suitable for further functionaliza-
tion (by stereoselective reduction of the carbonyl group and sub-
sequent oxidation of the double bond).
In this communication, the application of our methodology for
the preparation of long-chain monosaccharides, convenient pre-
cursors of complex polyhydroxylated compounds will be
presented.
One of the first examples of such methodology provided by Sec-
rist7 in the end of 1970s, applied the Wittig reaction for the prep-
aration a higher sugar 3—key-compound in the synthesis of the
antibiotic sugar hikozamine. The phosphonium salt 1 derived from
a properly blocked hexose was converted into an ylid 2, which
* Corresponding author. Tel.: +48 22 343 23 22; fax: +48 22 632 66 81.
E-mail address: sljar@icho.edu.pl (S. Jarosz).
0957-4166/$ - see front matter Ó 2008 Published by Elsevier Ltd.
doi:10.1016/j.tetasy.2008.05.010

1386
S. Jarosz et al. / Tetrahedron: Asymmetry 19 (2008) 1385–1391
O
P
OBn
O
O
I
OMe
OMe
PPh3
O
BnO
BnO
O
6
O
SugCH=CH-R'
+
7
O
O
O
decomposition
3
8
OR
OMe
OR
1
R'-CHO
OBn
O
O
(sugar aldehyde
base
derived from pentose)
BnO
12 O
6
8
O
O
O
BnO
+
PPh3
O
problems with selective
hydrolysis of the terminal
isopropylidene functionality
PPh3
-
OMe
9
O
Figure 4. Synthesis of a precursor of the C12-monosaccharide by phosphonate
methodology.
OR
OR
OR
2a
phase transfer conditions afforded the higher sugar enone 11 in
84% yield (Scheme 1).
OR
2b
Figure 2. Synthesis of hikozamine precursor by Secrist.
O
BnO BnO
OBn
O
7
O
OH
Sug
O
BnO
BnO
BnO
OH
O
BnO
O
i.
CMe2
OBn
O
O
BnO
MeO
11
O
10
1. MeOH / H (+)
2. MeP(O)(OMe)2/BuLi
1. im2CO
2. 2 equiv. Ph3P=CH2
Scheme 1. Reagents and conditions: (i) K2CO3, toluene, 18-crown-6, rt, 84%.
O
Reduction of such enones with zinc borohydride usually pro-
vides the higher sugar allylic alcohols with an (R)-configuration
at the newly created stereogenic centre in high yield and very high
stereoselectivity.11 However, this case was an exception; treat-
ment of the enone 11 with Zn(BH4)2 provided both alcohols (R)-
12 and (S)-12 in almost equal amounts (Table 1). The best selectiv-
ity was observed in the reaction of the enone 11 with K-Selectride.
O
OMe
O
PPh3
P
OMe
Sug
Sug
5
4
Sug
1-CHO
Sug1-CHO
heat
K2CO3 /
18-crown-6
toluene, rt
Table 1
Sug1
Reduction of enone 12 with various agents
O
Reducing agent
Products 12 (R):(S)
Overall yield (%)
6
Sug
Zn(BH4)2
DIBAL-H
NaBH4
K-Selectride
L-Selectride
56:44
71:29
52:48
78:22
76:24
85
91
82
89
80
Figure 3. Synthesis of higher carbon sugars via phosphorane and phosphonate
methodology.
2. Results and discussion
The configuration at the newly created stereogenic centre in
both alcohols was determined by CD spectroscopy, which is partic-
ularly useful for determination of the absolute configuration of the
threo-diols.12 Compounds (S)-12 and (R)-12 were converted into
Recently we have prepared the higher sugar precursor 9 by
reaction of the phosphonate 7 and readily available aldehyde 8
(Fig. 4).9 Although functionalization of the allylic C6–C8 bridge
could be performed highly stereoselectively and in high yield, we
faced a severe problem with selective deprotection of the terminal
position (C11–C12).
To overcome these difficulties in the model synthesis of long-
chain monosaccharides we have designed another precursor with
a readily accessible terminal position.
L-glycero-
D-gluco- and
D-glycero-D-gluco-heptoses, 13 and 14,
respectively (Scheme 2) by ozonolysis of the double bond, followed
by reduction of the crude ozonide. The positive Cotton effect
observed in the CD spectrum of the complex of diol 14 with
di-molybdenum tetraacetate indicated an (R)-configuration at the
C6-centre, while the negative value for the diastereoisomer 13
indicated a (6S)-configuration.
Further synthetic steps performed for both allylic alcohols pro-
vided the fully hydroxylated derivatives. First, the hydroxyl group
in either alcohol was protected as a benzyl ether (15 or 16) and fur-
ther cis-hydroxylated with osmium tetraoxide (catalytic version)13
which furnished the corresponding diols: 17/18 (from 15) and 19/
20 (from 16) (Scheme 3).
2.1. Synthesis of higher carbon sugars with thirteen carbon
atoms in the chain
The reaction of the phoshonate 7 with the readily available
2,3,4-tri-O-benzyl-5,6-O-isopropylidene-D
-glucose10 10 under mild

S. Jarosz et al. / Tetrahedron: Asymmetry 19 (2008) 1385–1391
1387
2.2. Attempts to invert the configuration in higher sugar allylic
alcohols
BnO BnO
S
BnO
HO
R
HO
O
BnO
BnO
9
6
9
BnO
BnO
6
Such diols are convenient precursors of higher analogues, which
can be prepared by, for example, hydrolysis of the isopropylidene
grouping and further elongation at the terminal position. Since diol
19 can be obtained with very high selectivity from the correspond-
ing allylic alcohol 16, it should be possible to increase the overall
yield of this compound by transformation of alcohol (R)-12 to
(S)-12. We decided, therefore, to perform a detailed study on the
interconversion between these two species. The most reasonable
choice for this purpose, the Mitsunobu inversion,15 did not afford
any product, and only the starting material was recovered after
this reaction. We turned our attention to the classical SN2 process,
that is, activation of the hydroxyl function as a triflate followed by
displacement of the leaving group with a carboxylate anion. This
reaction, however, proceeded via an unexpected route. The triflate
21 [prepared from the alcohol (S)-12] underwent in situ intra-
molecular substitution by an oxygen from the C11 centre with
simultaneous migration of the double bond towards the glucose
ring (Scheme 4).
BnO
(S)-12
O
O
O
BnO
MeO
BnO
MeO
i. ii.
i. ii.
12
(R)-
HO
HO
S
R
OH
BnO
OH
BnO
6
6
BnO
BnO
O
O
BnO
MeO
BnO
MeO
14
13
data for the complex with Mo2(OAc)4
λmax (Δe') 313.0 (-0.529)
λmax (Δe') 313.0 (+0.382)
275.5 (+0.356)
279.0 (-0.208)
Scheme 2. Reagents: (i) O3, CH2Cl2, MeOH, then Me2S; (ii) NaBH4.
The structure of this product was assigned on the basis of the
MS and NMR data. The signal in the ESI MS spectrum of the product
obtained after triflation of the alcohol (S)-12 observed at m/z: 865
[M+Na+] strongly suggested the elimination of benzyl alcohol from
the molecule. This was further supported by the 13C NMR data in
which only five signals of the quaternary carbon atoms from the
benzyl groups were seen (see Section 4). Moreover in the COSY
spectrum, the resonances of the double bond showed the cross
peaks to H-5 and H-8, which strongly suggested that the double
bond was shifted from the C7–C8 to the C6-C7 position, that is, to-
wards the glucose ring. The E-configuration across the double bond
was retained, as seen from the 1H NMR spectrum in which the
large coupling constant between the olefinic protons (J = 15.5 Hz)
was observed. On the basis of these data, we were able to propose
the cyclic structure represented by formula 22. The only point that
could not be solved by the spectroscopic data was the configura-
tion at the newly created stereogenic centre C8. This was, however,
established by X-ray crystallographic analysis; the structure of the
compound 22 is shown in Figure 5.
The absolute configurations of all diols with the relative threo
arrangement of both hydroxyl groups were determined by CD
spectroscopy of the complexes of the diols with di-molybdenum
tetraacetate. The negative Cotton effect observed for the complexes
of the diols 18 and 19 with dimolybdenum tetraacetate unambig-
uously indicated a (7S,8S)-configuration, while the positive effect
for such complexes of the diols 17 and 20 indicated a (7R,8R)-con-
figuration at the newly created stereogenic centres (Table 2).
Table 2
Assignment of the configuration at the C7,C8 centres in diols 17–20 by CD
Compound kmax
(
D
e0
)
kmax
(
D
e0
)
Cotton effect Configuration
17
18
19
20
280 (ꢀ0.0272)
271.5 (+0.3274)
275.4 (+0.1171)
266.8 (ꢀ0.5628) 335.2 (+0.1961)
315 (+1.9978)
+
ꢀ
ꢀ
+
(7R,8R)
(7S,8S)
(7S,8S)
(7R,8R)
317.5 (ꢀ0.9066)
336.4 (ꢀ0.3706)
As expected from the rules elaborated upon by Kishi for the
osmylation of allylic alcohols (or their derivatives),14 the dihydr-
oxylation of the (6S)-isomer 16 was highly selective and almost
exclusively afforded diol 19 with an anti-relationship of the newly
introduced hydroxyl groups to both oxygen functions flanking the
double bond (ratio 19:20 = 97:3). Selectivity in the osmylatation of
the (6R)-isomer 15 was low and both diols 17 and 18 were ob-
tained in comparable amounts (17:18 = 58:42).
The same process was observed when the isomeric alcohol (R)-
12 was triflated. The NMR spectra of this product were similar to
the spectra of 22 (although it differed quite significantly) which
pointed to the fact that the rearrangement of triflate 23 provided
stereoisomer 24 with a different configuration at the C8 centre.
The most important resonances of both cyclic products 22 and
23 are shown in Table 3.
OBn OBn
OBn OBn
8
Gluc
Gluc
O
13
6
O
OBn
OBn O
OBn
OBn
O
i.
15
i.
16
ii.
(R)-12
ii.
12
(S)-
OH OBn
OH
OBn
OH OBn
OH OBn
Gluc
Gluc
Gluc
Gluc
OBn OH
OBn OH
20
OBn OH
17
OBn OH
18
19
19:20 = 97:3
17:18 = 58:42
t
Scheme 3. Reagents and conditions: (i) BnCl, 50% NaOH, Bu4NBr (cat.), benzene, rt; (ii) OsO4 (cat.), NMO, tBuOH, H2O, THF, rt, 48 h.

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S. Jarosz et al. / Tetrahedron: Asymmetry 19 (2008) 1385–1391
i.
(S)-12
m/z = 973 (950 + Na+)
O
O
BnO
BnO
BnO BnO
6
O
11
H
Gluc
6
O
11
8
OBn
5
8
TfO
BnO
O
O
BnO
MeO
BnO
22
21
1
i.
+
(R)-12
842
m/z = 865 (
+ Na )
O
O
BnO BnO
BnO
6
Gluc
BnO
O
H
O
11
8
OBn
TfO
BnO
O
O
BnO
MeO
BnO
23
24
Scheme 4. Reagents and conditions: (i) Tf2O, CH2Cl2, py, 0 °C, 30 min.
The fact that each stereoisomeric allylic alcohol was converted
into a single tetrahydrofuran derivative differing from each other
only by configuration at the newly created stereogenic centre at
the C8 position pointed to the concerted mechanism of the
rearrangement.
This process resembles similar reactions, in which the double
bond is activated by iodine and then attacked by an oxygen atom
bearing a benzyl group (Fig. 6).16
Bn
O
Bn
O
O
+
I
I
Figure 6. Cyclization of pentenyl alcohol derivatives.
Figure 5. The X-ray structure of compound 22.
However, this reaction is different; the double bond is activated
by the presence of a strong electron withdrawing group (triflate) at
the allylic position, so the attack of the oxygen functionality on the
electron poor olefinic bond results in cyclization with simultaneous
migration of the double bond.
Table 3
The NMR data for rearranged products 22 and 24
3. Conclusion
22
24
d (ppm), J (Hz)
d (ppm), J (Hz)
The model synthesis of higher carbon sugars—tridecoses has
been elaborated upon. The presence of the isopropylidene func-
tionality at the terminal (C12–C13) position makes this ‘end’ read-
ily accessible for further transformations (e.g., elongation by
another sugar sub-unit which may result in even higher ana-
logues). The unusual rearrangement of the higher sugar allylic
skeleton, proceeding with the cyclization and simultaneous migra-
tion of the double bond, was observed when the allylic hydroxyl
group was activated as a triflate.
H-7
H-6
5.96, dd
J6,7 = 15.5
J7,8 = 7.5
6.0, ddd
J7,5 = 1.2
J6,7 = 15.6
J7,8 = 7.3
5.85, ddd
J5,6 = 5.8
J6,7 = 15.6
J6,8 = 0.8
4.52, dd
J7,8 = 7.3
J8,9 = 3.6
3.81, dd
J8,9 = 3.6
J9,10 = 0.9
128.8
5.79, dd
J5,6 = 6.5
J6,7 = 15.5
H-8
H-9
4.32, dd
J7,8 = 7.5
J8,9 = 3.0
3.8, d
4. Experimental
J8,9 = 3.0
C-7
C-6
C-8
C-9
132.1
129.5
84.6
4.1. General
130.3
81.4
83.6
The NMR spectra were recorded in CDCl3 at 303 K with a Bruker
DRX Avance 500 spectrometer equipped with a TBI 50SB H-C/BB-D-
87.8

S. Jarosz et al. / Tetrahedron: Asymmetry 19 (2008) 1385–1391
1389
05 Z-G probehead, operating at 500.133 and 125.773 MHz for 1H
and 13C, respectively (internal Me4Si). The assignment of the 1H
and 13C NMR signals was made using results of 2D methods includ-
ing COSY, HSQC and DEPT correlations. The relative configurations
of the protons were determined based on NOESY. The 1H- and 13C-
aromatic resonances occurring at the typical d values were omitted
for simplicity. Mass spectra were recorded with an ESI/MS Mariner
(PerSeptive Biosystem) mass spectrometer. Optical rotations were
measured with a Digital Jasco polarimeter DIP-360 (k = 589 nm) for
solutions in CHCl3 (c 1) at rt. CD spectra were measured between
650 and 230 nm at room temperature with a Jasco J715 spectropo-
larimeter using DMSO solutions in cells of 0.2 path length (spectral
J2,3 = J3,4 = 9.2 Hz, H-3), 3.93–3.84 (m, 2H, H-130, H-13), 3.76 (dd,
J10,11 = J11,12 = 4.2 Hz, H-11), 3.70 (dd, H-4), 3.58 (dd, J9,10 = 6.3 Hz,
H-10), 3.42 (dd, H-2), 3.31 (s, OCH3), 1.35 and 1.26 (2s, CMe2);
13C NMR: d 194.6 (C-6), 144.7 (C-8), 128.2 (C-7), 138.6, 138.3,
138.1, 138.0, 137.96, 137.6 (6 ꢁ Cquat), 108.2 (CMe2), 98.8 (C-1),
81.7 (C-3), 81.65 (C-10), 79.5 (C-9), 79.47 (C-2), 79.1 (C-4), 78.8
(C-11), 76.7 (C-12), 75.8, 74.9, 74.89, 74.1, 73.5 (5 ꢁ CH2Ph), 72.9
(C-5), 72.1 (CH2Ph), 65.9 (C-13), 55.7 (OCH3), 26.4 and 24.9 (CMe2).
Anal. Calcd for C59H64O11ꢂ1.5H2O: C, 72.59; H, 6,76. Found: C,
72,41; H, 6.92.
4.4. Reduction of the enone 11
band width 1 nm, sensitivity 10 ꢁ 10ꢀ6 or 20 ꢁ 10ꢀ6
DA-unit/nm).
Depending on the S/N-ratio, the k-scan speed was 0.2 or 0.5 nm/s.
For CD measurements the chiral diol (1–3 mg) was dissolved in a
solution of the stock [Mo2(OAc)4] complex (6–7 mg) in DMSO
(10 mL) so that the molar ratio of the stock complex to diol was
about 1:0.3 to 1:0.7. As the true concentrations of the individual
To a cooled (0 °C) solution of enone 11 (9.7 g, 10.25 mmol) in
dry ether (80 mL), zinc borohydride (25 mL of a 0.5 M solution in
dry ether) was added and the mixture was stirred at 0 °C for
30 min. Excess of hydride was decomposed with water (25 mL),
the organic phase was separated, washed with diluted (5%) sulfuric
acid (50 mL), water (50 mL), dried and concentrated, and the prod-
ucts were isolated by column chromatography (hexane–ethyl ace-
tate, 7:1 to 1:1) as oils. Yield of (R)-12: 4.6 g (47.6%); yield of (S)-
12: 3.63 g (37.4%).
optically active complexes are unknown, apparent
D
e0 values are
given, calculated from the total ligand concentration and assuming
100% complexation. [Mo2(OAc)4] and DMSO (Uvasol) were com-
mercially available from Fluka AG and E. Merck, respectively, and
were used without further purification.
Column chromatography was performed on silica gel (Merck,
70–230 or 230–400 mesh). Methylene chloride was distilled from
CaH2 and THF from potassium prior to use. Organic solutions were
dried over anhydrous magnesium sulfate.
Reduction of the enone 11 with other reducing agents was per-
formed under standard conditions and the results are presented in
Table 1.
4.4.1. Alcohol (R)-12
[a]
D = +29.1; MS m/z: 973.4 [C59H66O11 (M+Na)+ = 973]; 1H
4.2. The X-ray crystallographic data of 12
NMR: d 5.70 (dd, J6,7 = 6.8, J7,8 = 15.7 Hz, H-7), 5.60 (dd,
J8,9 = 7.3 Hz, H-8), 4.55 (d, J1,2 = 3.5 Hz, H-1), 4.33 (dd, J5,6 = 3.7 Hz,
H-6), 4.17–4.14 (m, 1H, H-12), 4.1 (dd, J9,10 = 6.9 Hz, H-9), 4.01
Crystallographic data for the structure of 22 have been depos-
ited with the Cambridge crystallographic Data Centre as Supple-
mentary Publication No. CCDC 685220. Diffraction data were
collected at 100 K by using a Kappa CCD diffractometer with
0
0
(dd, J2,3 = 9.4, J3,4 = 9.1 Hz, H-3), 3.93 (dd, J12,13 = 7.2, J13,13
=
8.1 Hz, H-130), 3.85 (dd, J12,13 = 6.9 Hz, H-13), 3.83 (dd, J10,11 = 3.9,
J11,12 = 4.1 Hz, H-11), 3.75 (dd, J4,5 = 10.1 Hz, H-5), 3.52 (dd, H-10),
3.42 (dd, H-2), 3.39–3.35 (m, H-4), 3.33 (s, OCH3), 1.37 and 1.26
(2s, CMe2); 13C NMR: d 138.6, 138.59, 138.5, 138.2, 137.97,
137.92 (6 ꢁ Cquat), 132.6 (C-7), 130.2 (C-8), 108.0 (CMe2), 97.7 (C-
1), 82.1 (C-3), 82.1 (C-10), 80.8 (C-9), 80.1 (C-2), 79.0 (C-4), 78.9
(C-11), 76.9 (C-12), 75.5, 74.9, 74.5, 73.9, 73.2 (5 ꢁ CH2Ph), 72.3
(C-5), 71.9 (C-6), 70.8 (CH2Ph), 65.7 (C-13), 55.2 (OCH3), 26.5 and
24,8 (CMe2). Anal. Calcd for C59H66O11ꢂ0.5H2O: C, 73.80; H, 7.03.
Found: C, 77.88; H, 6.79.
graphite monochromated MoK
a radiation. The structure was
solved by direct methods (SHELXS-97) and refined on F2 by full-ma-
trix least-squares method (SHELXL-97). The structure contains three
symmetry independent molecules of 22 all having the same abso-
lute configuration but slightly different conformations. Formula:
3C52H58O10
8.5731(2), c = 34.031(1) Å, b = 98.56(1)°, V = 6896.9(4) Å3, Z = 2,
F(000) = 2700, (MoK R1 = 0.1005 [I > 2 (I)],
) = 0.08 mmꢀ1
wR2 = 0.2112 for all data.
, monoclinic, space group P21, a = 23.906(1), b =
l
a
,
r
4.4.2. Alcohol (S)-12
4.3. Methyl 2,3,4,9,10,11-hexa-O-benzyl-7,8-dideoxy-7,8-
[a]
D = +17.9; MS m/z: 973.4 [C59H66O11 (M+Na)+]; 1H NMR: d
didehydro-12,13-O-isopropylidene-
7(E)-eno-1,5-pyranosid-6-ulose 11
a-D
-gluco-
D-gluco-tridec-
5.68–5.65 (m, 2H, H-7, H-8), 4.50 (d, J1,2 = 3.5 Hz, H-1), 4.30–4.28
(m, 1H, H-6), 4.15–4.10 (m, 1H, H-12), 4.11 (dd, J8,9 = 6.3,
J9,10 = 6.4 Hz, H-9), 4.0 (dd, J2,3 = 9.4, J3,4 = 9.3 Hz, H-3), 3.96 (dd,
To a solution of aldehyde 10 (9.8 g, 20 mmol) and phosphonate
7 (14.6 g, 25 mmol) in dry toluene (500 mL) anhydrous potassium
carbonate (8.5 g) was added followed by 18-crown-6 (50 mg.;
Bu4NBr can also be used as catalyst without significant decrease
of the yield of the product). After stirring for 12 h at room temper-
ature, TLC (hexane–ethyl acetate, 3:1) indicated the disappearance
of the aldehyde and the formation of a new, less polar product,
which was visible under UV light. Water (500 mL) was added,
the organic phase was separated and the aqueous one extracted
with AcOEt (500 mL). The combined organic solutions were
washed with water (2 ꢁ 250 mL), brine (250 mL), dried and con-
centrated, and the product was isolated by column chromatogra-
phy (hexane–ethyl acetate, 6:1 to 4:1) as an oil (15.9 g,
16.8 mmol, 84%).
J12,13 = 7.3, J13,13 = 8.1 Hz, H-130), 3.88 (dd, J12,13 = 6.8 Hz, H-13),
3.86 (dd, J10,11 = 3.9, J11,12 = 4.6 Hz, H-11), 3.66 (dd, J4,5 = 9.6 Hz,
H-4), 3.52–3.44 (m, 4H), 3.2 (s, OCH3), 1.38 and 1.26 (2 ꢁ s,
CMe2); 13C NMR: d 138.7, 138.6, 138.5, 138.4 (double intensity),
138.3, 138.1 (6 ꢁ Cquat), 134.6 (C-8), 128.1 (C-7), 108.1 (CMe2),
98.4 (C-1), 82.1 (C-3), 82.0 (C-10), 80.4 (C-9), 79.9 (C-2), 78.4 (C-
11), 77.6 (C-4), 77.2 (C-12), 75.7, 75.2, 74.9, 73.8, 73.5 (5 ꢁ CH2Ph),
72.2 (C-5), 70.8 (CH2Ph), 69.3 (C-6), 65.7 (C-13), 55.2 (OCH3), 26.5
and 24.9 (CMe2). Anal. Calcd for C59H66O11: C, 74.52; H, 6.95.
Found: C, 74.29; H, 7.08.
0
0
4.5. Determination of the configuration of the stereogenic
centres at C-6 in the allylic alcohols 12
[
a]
D = +6.9; HR-MS m/z: 971.4341 [C59H64O11 (M+Na)+ requires:
Allylic alcohol (S)-12 (123 mg, 0.129 mmol) was dissolved in
methylene chloride (20 mL) containing small amounts of methanol
(1 mL). The mixture was cooled to ꢀ78 °C and ozone (5% in oxygen)
was bubbled through the solution until a blue colour persisted
971.4370]; 1H NMR: d 7.0 (dd, J7,8 = 15.8 Hz, J8,9 = 5.6 Hz, H-8), 6.56
(dd, J7,9 = 1.2 Hz, H-7), 4.55 (d, J1,2 = 3.5 Hz, H-1), 4.30–4.26 (m, 1H,
H-9), 4.27 (d, J4,5 = 9.7 Hz, H-5), 4.15–4.10 (m, 1H, H-12), 4.0 (dd,

1390
S. Jarosz et al. / Tetrahedron: Asymmetry 19 (2008) 1385–1391
(15 min). Dimethyl sulfide (4 equiv) was added, the mixture stirred
at rt for 15 min and concentrated. The residue was dissolved in
methanol (20 mL), and sodium borohydride added after which
the mixture was stirred for 30 min at rt. The solution was parti-
tioned between water (10 mL) and ether (20 mL), and the organic
phase was separated, washed with water (2ꢁ10 mL), brine
(10 mL), dried and concentrated. Chromatographic purification
(hexane–ethyl acetate, 2:1 to 1:2) of the residue afforded the re-
duction product of aldehyde 10 and the heptose 13 (39 mg,
0.079 mmol, 61%). The NMR spectrum of the thus obtained com-
pound was identical with the known heptose 13;17 the CD spec-
trum of the complex of 13 with [Mo2(OAc)4] showed the
CMe2); 13C NMR: d 138.6, 138.57, 138.51, 138.12, 138.10, 137.95,
137.6 (7 ꢁ Cquat), 132.0 (C-8), 131.6 (C-7), 108.2 (CMe2), 98.2 (C-
1), 82.4 (C-3), 81.8 (C-10), 79.7 (C-2), 79.6 (C-9), 78.5 (C-11), 77.4
(C-4), 76.7 (C-12), 76.4 (C-6), 75.8, 74.74, 74.71, 74.0, 73.4
(5 ꢁ CH2Ph), 72.9 (C-5), 70.8, 70.7 (2 ꢁ CH2Ph), 65.7 (C-13), 55.0
(OCH3), 26.4 and 24.9 (CMe2). Anal. Calcd for C66H72O11 + 1/2
H2O: C, 75.50; H, 6.96. Found: C, 75.39; H, 7.07.
4.8. Osmylation of compound 15
To a solution of olefin 15 (0.1092 g, 0.105 mmol) in THF (8 mL)
containing tert-butyl alcohol (0.8 mL) and water (0.1 mL), N-meth-
ylmorpholine-N-oxide (160 mg, 1.2 mmol) and osmium tetraoxide
negative Cotton effect [kmax
(D
e0): 313.0 (ꢀ0.529) and 275.5
t
(+0.356)], which proved the 6(S) configuration of this molecule.
Analogously, alcohol (R)-12 was converted into heptose 14; the
CD spectrum of the complex of 14 with [Mo2(OAc)4] showed the
(0.5 mL of a ꢃ2% solution in BuOH) were added and the mixture
was stirred at room temperature (TLC monitoring in hexane–ethyl
acetate, 3:1) for 48 h. Methanol (20 mL) was added followed by
saturated aq NaHSO3, the mixture was stirred for 30 min, then fil-
tered through Celite and the solution was partitioned between
water (20 mL) and AcOEt (100 mL). The organic phase was sepa-
rated, washed with water (2 ꢁ 50 mL), brine (50 mL), dried, con-
centrated and the products were isolated by column chromato-
graphy (hexane–ethyl acetate, 3:1 to 2:1) as an inseparable
(58:42) mixture of methyl 2,3,4,6,9,10,11-hepta-O-benzyl-12,13-
positive Cotton effect [kmax
(D
e0): 313.0 (+0.382) and 279.0
(ꢀ0.208)], which proved the (6R)-configuration of this molecule.
4.6. Methyl 2,3,4,6,9,10,11-hepta-O-benzyl-7,8-dideoxy-7,8-
didehydro-12,13-O-isopropylidene-a-D-glycero-D-gulo-D-gluco-
tridec-7(E)-eno-1,5-pyranoside 15
To a cooled (5 °C) solution of the alcohol (R)-12 (159 mg;
0.167 mmol) in DMF (5 mL) containing catalytic amount (5 mg)
of imidazole, sodium hydride (50% suspension in mineral oil,
28.8 mg; 1.2 equiv) was added slowly. The cooling bath was re-
moved and the mixture was stirred for 30 min at rt. Benzyl bro-
mide (188 mg; 1.1 equiv) was added and the stirring was
continued for another 3 h at rt. The excess hydride was decom-
posed by the careful addition of water (1 mL), and the mixture
was partitioned between ether (5 mL) and water (3 mL). The or-
ganic phase was separated and the aqueous one extracted with
ether (3ꢁ5 mL). The combined organic solutions were washed with
water (5 mL), brine (5 mL), dried, concentrated and the product
was isolated by column chromatography (hexane–ethyl acetate,
9:1 to 4:1) to afford 15 (138.9 mg, 0.1336 mmol, 80%) as an oil.
O-isopropylidene-
a-D-arabino-D-gulo-D-gluco-17 and a-D-arabino-
D
-gluco- -gluco-trideca-1,5-pyranoside 18 (100 mg, 0.09 mmol,
D
86%). Separation of these diols was possible [after their conversion
into di-benzoates (with 2.2 equiv BzCl in pyridine containing
DMAP)] by preparative TLC (hexane–ethyl acetate, 6:1).
4.8.1. Dibenzoate 17-Bz
[a
]
D = ꢀ3.0; MS m/z: 1305.5 [C80H82O15 (M+Na)+]; 1H NMR d
(MeOD): 6.44 (dd, J7,8 = 1.7, J8,9 = 8.0 Hz, H-8), 5.95 (dd,
J6,7 = 7.7 Hz, H-7), 4.70 (d, J1,2 = 3.5 Hz, H-1), 4.15 (dd, J = 6.9,
J = 11.2 Hz, H-12), 4.08 (d, H-6), 4.02 (dd, J9,10 = 3.6 Hz, H-9),
3.94–3.90 (m, 2H, H-130, H-5), 3.81 (dd, J10,11 = 7.2 Hz, H-10),
3.80–3.75 (m, 3H, H-3, H-13, H-11), 3.64 (dd, J3,4 = 8.7,
J4,5 = 10.4 Hz, H-4), 3.14 (dd, J2,3 = 9.6 Hz, H-2), 3.24 (s, OCH3), 1.2
and 1.06 (2 ꢁ s, CMe2); 13C NMR: d 167.1 and 166.9 (2 ꢁ C@O),
140.0, 139.9, 139.6, 139.5, 139.4, 139.2, 138.7, 138.1, 137.4
(9 ꢁ Cquat), 134.9 and 134.5 (2 ꢁ C-orto), 109.1 (CMe2), 99.3 (C-1),
83.5 (C-3), 87.1 (C-2), 81.6 (C-9), 81.4 (C-10), 80.2, 80.15, 79.3 (C-
4), 78.6 (C-12), 76.3, 76.2 (double intensity), 75.9, 75.6, 75.0, 74.1
(7 ꢁ CH2Ph), 73.0 (C-8), 72.2 (C-7), 72.0 (C-5), 66.5 (C-13), 56.4
(OCH3), 26.8 and 25.0 (CMe2).
[a]
D = +9.3; MS m/z: 1063.5 [C66H72O11 (M+Na)+]. 1H NMR: d 5.78
(dd, J6,7 = 8.1, J7,8 = 15.8 Hz, H-7), 5.51 (dd, J8,9 = 7.7 Hz, H-8), 4.64
0
(d, J1,2 = 3.6 Hz, H-1), 4.17 (ddd, J11,12 = 4.3, J12,13 = 7.0, J12,13
=
6.7 Hz, H-12), 4.14–4.11 (m, 2H, H-6, H-9), 4.02 (dd, J2,3 = 9.1,
J3,4 = 9.0 Hz, H-3), 3.96 (dd, J4,5 = 10.3, J5,6 = 1.5 Hz, H-5), 3.90 (dd,
J13,13 = 8.1 Hz, H-130), 3.87 (dd, H-13), 3.83 (dd, J10,11 = 4.1 Hz, H-
0
11), 3.54 (dd, J9,10 = 6.7 Hz, H-10), 3.42 (s, OCH3), 3.45–3.41 (m,
H-2), 3.34 (dd, H-4), 1.35 and 1.26 (2 ꢁ s, CMe2); 13C NMR: d
138.8, 138.6, 138.5, 138.3, 138.13, 138.11, 138.06 (7 ꢁ Cquat),
132.4 (C-8), 131.1 (C-7), 108.2 (CMe2), 99.6 (C-1), 82.3 (C-3), 81.2
(C-10), 80.5 (C-9), 80.2 (C-2), 79.2 (C-11), 78.2 (C-6), 78.0 (C-4),
76.6 (C-12), 75.6, 74.9, 74.5, 74.1, 73.2 (5 ꢁ CH2Ph), 72.3 (C-5),
70.8, 70.4 (2 ꢁ CH2Ph), 65.8 (C-13), 55.0 (OCH3), 26.5 and 24,9
(CMe2). Anal. Calcd for C66H72O11: C, 76.15; H, 6.92. Found: C,
75.99; H, 6.91.
4.8.2. Dibenzoate 18-Bz
[a]
D = +37.4; MS m/z: 1305.5 [C80H82O15 (M+Na)+]; 1H NMR: d
6.27 (dd, J7,8 = 1.3, J6,7 = 8.8 Hz, H-7), 5.82 (dd, J8,9 = 4.1 Hz, H-8),
4.67 (d, J1,2 = 3.5 Hz, H-1), 4.21 (d, J4,5 = 9.99 Hz, H-5), 4.15 (dd,
J9,10 = 7.6 Hz, H-9), 4.03–3.97 (m, 4H, H-3, H-6, H-11, H-12), 3.83
(dd, J12,13 = 7.0, J13,13 = 8.2 Hz, H-130), 3.81 (dd, J3,4 = 9.2 Hz, H-4),
3.72 (dd, J10,11 = 3.5 Hz, H-10), 3.66 (dd, J12,13 = 6.9 Hz, H-13), 3.51
(dd, J2,3 = 9.7 Hz, H-2), 3.36 (s, OCH3), 1.31 and 1.19 (2 ꢁ s,
CMe2); 13C NMR: d 167.1 and 166.9 (2 ꢁ C@O), 140.1, 139.8,
139.76, 139.7, 139.5, 139.2, 139.1, 137.8, 134.8 (9 ꢁ Cquat), 134.1
and 132.0 (2 ꢁ C-ortho), 109.9 (CMe2), 98.6 (C-1), 83.3 (C-3),
81.43 (C-2), 81.41 (C-10), 81.0 (C-11), 79.7 (C-4), 79.0 (C-9), 78.5
(C-6), 77.7 (C-12), 76.2, 76.0. 75.97, 75.6, 75.4, 74.1, 73.9
(7 ꢁ CH2Ph), 73.3 (C-8), 72.6 (C-7), 71.7 (C-5), 67.2 (C-13), 55.5
(OCH3), 26.7 and 25.4 (CMe2).
0
0
4.7. Methyl 2,3,4,6,9,10,11-hepta-O-benzyl-7,8-dideoxy-7,8-
didehydro-12,13-O-isopropylidene-a-D-glycero-D-ido-D-gluco-
trideca-7(E)-eno-1,5-pyranoside 16
This compound was prepared from (S)-12 analogously as 15 in
75% yield. [a]
D = +44.7; MS (ESI) m/z: 1063.6 [C66H72O11 (M+Na)+];
1H NMR: d 5.92 (ddd, J6,7 = 8.3, J7,8 = 15.8, J7,9 = 0.7 Hz, H-7), 5.72
(dd, J8,9 = 7.3 Hz, H-8), 4.57 (d, J1,2 = 3.9 Hz, H-1), 4.23–4.19 (m,
1H, H-12), 4.14–4.12 (m, 1H, H-6), 4.09–4.05 (m, 1H, H-9), 3.96
0
0
4.9. Osmylation of the olefin 16
(dd, J2,3 = 9.5, J3,4 = 9.3 Hz, H-3), 3.93 (dd, J12,13 = 7.2, J13,13
=
8.0 Hz, H-130), 3.85 (dd, J12,13 = 6.8 Hz, H-13), 3.84 (dd, J10,11 = 3.7,
J11,12 = 4.7 Hz, H-11), 3.77 (dd, J4,5 = 9.1 Hz, H-4), 3.57 (dd, H-2),
3.48-3.44 (m, 2H, H-5, H-10), 3.09 (s, OCH3), 1.34 and 1.25 (2 ꢁ s,
Osmylation of olefin 16 (performed analogously as for 15) pro-
vided two products which were separated by column chromato-

S. Jarosz et al. / Tetrahedron: Asymmetry 19 (2008) 1385–1391
1391
graphy (hexane–ethyl acetate, 5:1 to 3:1); diol 19 (81%) and 20
(2.4%).
4.11. Methyl 8,11-anhydro-2,3,4,9,10-penta-O-benzyl-6,7-
dideoxy-6,7-didehydro-12,13-O-isopropylidene- -glycero-
ido- -gluco-tridec-6(E)-eno-1,5-pyranoside 24
a-
D
D-
D
4.9.1. Methyl 2,3,4,6,9,10,11-hepta-O-benzyl-12,13-O-
isopropylidene-
pyranoside 19
a
-
D
-arabino-
D
-ido-
D
-gluco-trideca-1,5-
This compound was prepared analogously as 22 from alcohol
(R)-12 in 75% yield. MS m/z: 865.4 [C59H66O11 (M+Na)+]; 1H
NMR: d 6.0 (ddd, J5,7 = 1.2, J6,7 = 15.6, J7,8 = 7.3 Hz, H-7), 5.85 (ddd,
J6,7 = 5.8, J6,8 = 0.8 Hz, H-6), 4.58 (d, J1,2 = 3.5 Hz, H-1), 4.52 (dd,
[a]
D = +11.1; MS m/z: 1097.5 [C66H74O13 (M+Na)+]; 1H NMR: d
4.64 (d, J1,2 = 3.6 Hz, H-1), 3.57 (dd, J2,3 = 9.7 Hz, H-2), 4.14–4.03
(m, 4H, H-3, H-5, H-8), 3.92–3.84 (m, 3H, H-130, H-13, H-9), 3.68
J8,9 = 3.6 Hz, H-8), 4.33 (ddd, J11,12 = 8.0, J12,13 = 6.2, J12,13 = 6.2 Hz,
0
(dd, J9,10 = 4.7, J10,11 = 8.8 Hz, H-10), 3.70 (dd, J3,4 = 9.7 J4,5
=
H-12), 4.14 (dd, J10,11 = 3.6 Hz, H-11), 4.11 (d, H-5), 4.10 (dd,
9.8 Hz, H-4), 4.25–4.20 (m, H-12), 4.0 (dd, J11,12 = J10,11 = 8.5 Hz,
H-11), 3.36 (s, OCH3), 1.36 and 1.25 (2 ꢁ s, CMe2); 13C NMR: d
138.7, 138.6, 138.2, 138.18, 138.1, 137.7, 137.5 (7 ꢁ Cquat), 108.3
(CMe2), 98.0 (C-1), 82.6, 80.1 (C-2), 80.07 (C-10), 78.2 (C-11),
77.2 (C-12), 76.9 (C-4), 76.7, 76.5 (C-9), 75.6, 74.4, 74.1, 74.0,
73.9, 73.7, 73.3 (7 ꢁ CH2Ph), 70.0, 69.4, 68.7, 65.7 (C-13), 55.3
(OCH3), 26.4 and 25.1 (CMe2). Anal. Calcd for C66H74O13: C, 73.74;
H, 6.89. Found: C, 73.76; H, 6.97.
J13,13 = 8.5 Hz, H-130), 4.04 (dd, J9,10 = 0.9 Hz, H-10), 3.97 (dd,
0
J2,3 = 9.5, J3,4 = 9.2 Hz, H-3), 3.95 (dd, H-13), 3.81 (dd, H-9), 3.51
(dd, H-2), 3.33 (s, OCH3), 3.25 (dd, J4,5 = 9.6 Hz, H-4),1.39 and
1.36 (2 ꢁ s, CMe2); 13C NMR: d 138.8, 138.3, 138.2, 138.0, 137.9
(5 ꢁ Cquat), 130.3 (C-6), 128.8 (C-7), 108.8 (CMe2), 98.1 (C-1), 83.6
(C-9), 82.4 (C-4), 81.8 (C-10), 81.76 (C-3), 81.4 (C-11), 81.37 (C-
8), 80.0 (C-2), 75.8, 75.0, 73.4 (3 ꢁ CH2Ph), 73.2 (C-12), 72.6, 72.1
(2 ꢁ CH2Ph), 70.1 (C-5), 69.3 (C-6), 67.6 (C-13), 55.1 (OCH3), 26.8
and 25.6 (CMe2).
4.9.2. Methyl 2,3,4,6,9,10,11-hepta-O-benzyl-12,13-O-
isopropylidene-
pyranoside 20
a-D-arabino-D-manno-D-gluco-trideca-1,5-
References
MS m/z: 1097.5 [C66H74O13 (M+Na)+]; 1H NMR: d 4.63 (d,
J1,2 = 3.3 Hz, H-1), 4.45 (dd, 1H, J = 8.8, J = 11.5 Hz), 4.22 (m, 1H),
4.13–4.03 (m, 4H), 3.97 (t, 1H, J = 4.3 Hz), 3.92–3.83 (m, 3H), 3.60
(m, 1H), 3.56 (dd, J2,3 = 9.7 Hz, H-2), 3.36 (s, OCH3), 1.35 and 1.25
(2 ꢁ s, CMe2); 13C NMR: d 138.7, 138.6, 138.2, 138.22, 138.1,
137.7, 137.5 (7 ꢁ Cquat), 108.3 (CMe2), 97.9 (C-1), 82.6, 80.2, 80.1,
78.3, 76.5, 75.6, 74.4, 74.1, 74.0, 73.99, 73.8, 73.3 (7 ꢁ CH2Ph),
70.0, 69.4, 68.8, 70.0, 69.4, 68.8, 65.7 (C-13), 55.3 (OCH3), 26.4
and 25.1 (CMe2).
1. Kiefel, M. J.; von Itzstein, M. Chem. Rev. 2002, 102, 471; Angata, T.; Varki, A.
Chem. Rev. 2002, 102, 439; Unger, F. M. Adv. Carbohydr. Chem. Biochem. 1981, 38,
324; Hansson, J.; Oscarson, S. Curr. Org. Chem. 2000, 4, 535; Li, L. S.; Wu, Y. L.
Curr. Org. Chem. 2003, 7, 447.
2. Takatsuki, A.; Arima, G.; Tamura, J. J. Antibiot. 1971, 24, 215.
3. Uchida, K.; Ichikawa, T.; Shimauchi, Y.; Ishikura, T.; Ozaki, A. J. Antibiot. 1971,
76, 254.
4. Brimacombe, J. S.. In Studies in Natural Products Chemistry; Atta-ur-Rahman, Ed.;
Elsevier: Amsterdam, 1989; Vol. 4, pp 157–158; Dondoni, A.; Fantin, G.;
Fogagnolo, M.; Medici, A.; Pedrini, P. J. Org. Chem. 1989, 54, 693.
5. For a review see: Danishefsky, S. J.; DeNinno, M. P. Angew. Chem., Int. Ed. Engl.
1987, 26, 15; Jurczak, J.; Bauer, T.; Jarosz, S. Tetrahedron Lett. 1984, 25, 4809;
Jurczak, J.; Bauer, T.; Jarosz, S. Tetrahedron 1986, 42, 6477.
6. Selected papers: Postema, M. H. D. Tetrahedron 1992, 48, 8545; Postema, M. H.
D.; Calimente, D. Glycochemistry: Principles, Synthesis & Applications. In C-
Glycoside Synthesis: Recent Developments and Current Trends; Wang, P. G.,
Bertozzi, C., Eds.; Marcel Dekker, 2000; p 77. Chapter 4; Bruns, R.; Kopf, J.; Köll,
P. Chem. Eur. J. 2000, 6, 1337; Liu, L.; McKee, M.; Postema, M. H. D. Curr. Org.
Chem. 2001, 5, 1133; Dondoni, A.; Giovanni, P. P.; Marra, A. J. Chem. Soc., Perkin
Trans. 1 2001, 2380; Jarosz, S.; Zamojski, A. Curr. Org. Chem. 2003, 7, 13. and
references cited therein; Taillefumier, C.; Chapleur, Y. Chem. Rev. 2004, 104,
263;; Chambers, D. J.; Evans, G. R.; Fairbanks, A. J. Tetrahedron: Asymmetry
2005, 16, 45; Juhasz, Z.; Micskei, K.; Gal, E.; Somsak, L. Tetrahedron Lett. 2007,
48, 7351; Graziani, A.; Amer, H.; Zamyatina, A.; Hofinger, A.; Kosma, P.
Tetrahedron: Asymmetry 2007, 18, 115; Denton, R. W.; Cheng, X.; Tony, K. A.;
Dilhas, A.; Hernández, J. J.; Canales, A.; Jiménez-Barbero, J.; Mootoo, D. R. Eur. J.
Org. Chem. 2007, 645. and references cited therein.
4.10. Methyl 8,11-anhydro-2,3,4,9,10-penta-O-benzyl-6,7-
dideoxy-6,7-didehydro-12,13-O-isopropylidene-a-D-glycero-D-
gulo- -gluco-tridec-6(E)-eno-1,5-pyranoside 22
D
This reaction was performed under an argon atmosphere. A
solution of allyl alcohol (S)-12 (119.7 mg, 0.126 mmol) in dry
CH2Cl2 (5 mL), containing dry pyridine (0.25 mL) was cooled to
0 °C, and triflic anhydride (53.2 g, 0.189 mmol, 1.5 equiv) was
added in one portion. After stirring for 30 min at 0 °C (TLC monitor-
ing in hexane–ethyl acetate, 2:1), the mixture was partitioned be-
tween CH2Cl2 (5 mL) and water (3 mL). The organic phase was
separated, washed with 10% CH3COONa (3 ꢁ 3 mL), dried, concen-
trated, and the product was isolated by column chromatography
(hexane–ethyl acetate, 2:1). It was further crystallized from meth-
anol to afford pure 22 (79.6 mg, 0.0945 mmol, 75%); mp: 100–
7. Secrist, J. A., Jr.; Wu, S. R. J. Org. Chem. 1979, 44, 1434; Secrist, J. A.; Barnes, K. D.;
Wu, S.-R. In Trends in Synthetic Carbohydrate Chemistry; Horton, E. D., Hawking,
D. L., McCorrey, G. J., Eds.; ACS Symposium Series; Oxford University Press,
1989; Vol. 386, p 93.
8. Jarosz, S.; Mach, M. J. Chem. Soc., Perkin Trans. 1 1998, 3943; for a review of our
methodology see: Jarosz, S. J. Carbohydr. Chem. 2001, 20, 93; Jarosz, S. Curr. Org.
Chem., in press.
101 °C;
[
a
]
D = ꢀ4.7; MS m/z: 865.4 [C59H66O11 (M+Na)+]; 1H
NMR: d 5.96 (dd, J6,7 = 15.5, J7,8 = 7.5 Hz, H-7), 5.79 (dd, J5,6
=
9. Jarosz, S.; Gajewska, A. Polish J. Chem. 2007, 81, 1949.
6.5 Hz, H-6), 4.57 (d, J1,2 = 3.3 Hz, H-1), 4.41–4.35 (m, 1H, H-12),
4.32 (dd, J8,9 = 3.0 Hz, H-8), 4.1 (dd, J4,5 = 9.4 Hz, H-5), 4.05–3.93
(m, 5H, H-3, H-130, H-13, H-10, H-11), 3.81 (d, H-9), 3.51 (dd,
J2,3 = 9.7 Hz, H-2), 3.35 (s, OCH3), 3.25 (dd, J3,4 = 9.5 Hz, H-4), 1.39
and 1.36 (2 ꢁ s, CMe2); 13C NMR: d 138.8, 138.2, 138.1, 138.0,
137.6 (5 ꢁ Cquat), 132.1 (C-7), 129.5 (C-6), 108.8 (CMe2), 98.1 (C-
1), 87.8 (C-9), 84.6 (C-8), 82.6 (C-10), 82.2 (C-4), 82.17 (C-11),
81.6 (C-3), 79.8 (C-2), 75.8, 75.0, 73.3 (3 ꢁ CH2Ph), 73.0 (C-12),
71.9, 71.7 (2 ꢁ CH2Ph), 70.5 (C-5), 67.4 (C-13), 55.2 (OCH3), 26.7
and 25.5 (CMe2). Anal. Calcd for C59H66O11 + H2O: C, 73.14; H,
7.02. Found: C, 73.21; H, 6.99. The X-ray structure is presented in
Figure 5.
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