Facile conversion of O-silyl protected sugars into their corresponding formates using POCl3·DMF complex

Article abstract of DOI:10.1016/j.tet.2004.07.056

The direct O-formylation of two selectively protected sugar derivatives using the Vilsmeier-Haack (V-H) complex POCl₃·DMF was studied. Primary O-TBDMS and O-TBDPS ethers of sucrose, the most common disaccharide, underwent regio and chemoselecti

Full text of DOI:10.1016/j.tet.2004.07.056

Tetrahedron 60 (2004) 9235–9243
Facile conversion of O-silyl protected sugars into their
corresponding formates using POCl3$DMF complex
*
Marta M. Andrade and M. Teresa Barros
´ ˆ
REQUIMTE/CQFB, Departamento de Quımica, Faculdade de Ciencias e Tecnologia, Universidade Nova de Lisboa,
2829-516 Caparica, Portugal
Received 10 June 2004; revised 8 July 2004; accepted 22 July 2004
Available online 28 August 2004
Abstract—The direct O-formylation of two selectively protected sugar derivatives using the Vilsmeier–Haack (V–H) complex POCl3$DMF
was studied. Primary O-TBDMS and O-TBDPS ethers of sucrose, the most common disaccharide, underwent regio and chemoselective
O-formylation with this formylating agent. This conversion was also studied with a monosaccharide analogue.
q 2004 Elsevier Ltd. All rights reserved.
1. Introduction
extension reactions particularly through Wittig type
olefinations.
Carbohydrates are fundamental to life. They are involved in
many essential biological processes: they act as an energy
source, in biological signalling and recognition mechanisms
and as basic building blocks, for example, they are part of
DNA, RNA, starch, cellulose, chitin and cotton.1 The great
advantage in the use of carbohydrates is that they are natural
products produced in large quantities; glucose is the most
abundant organic molecule on the planet (mostly in the form
of its polymer cellulose); sucrose is the most common sugar
and its annual production exceeds 120 million tons.
Several one-step formylation methods have been reported
over the years, using formylation agents such as formyl
fluoride, formic anhydride, acetic-formic anhydride,13
2-(N-methyl-N-formylamino)pyridine, dimethylchloro-
methyl-ammonium chloride, N-formylbenzotriazole14 and
N,N-dimethylformamide,15 among many others.16 In par-
ticular, the one step conversion of silyl ethers into their
corresponding formates was described using PPh3/CBr4 in
HCOOEt/H2O17 and more recently by the use of the
Vilsmeier–Haack (V–H) complex POCl3/DMF.18–20
Sugars contain numerous functional groups and chiral
centres, so the problem of protecting groups is one of the
fundamental tasks in carbohydrate chemistry. A specific
differentiation of the hydroxyl groups can be achieved by
etherification procedures, such as tritylation or silylation,
which are now widely used and well described.2,3
In this work, we extend the above cited formylation method
with the Vilsmeier–Haack complex to the conversion of
O-TBDPS and O-TBDMS ethers of mono and disaccharides
into the corresponding formates. We have proven its
usefulness in the fast, easy and selective preparation
of 6-O-formates of glucose and we have also explored the
chemo and regioselectivity, as well as the applicability to
acid sensitive and more complex substrates, such as sucrose,
without the need for addition of a base, which retards the
reaction.18–20
The selective derivatisation of sugars with unsaturated
moieties is one of the easiest routes to the preparation of
polymers4–8 and for the construction of asymmetric
molecules using sugars as chiral auxiliaries.9–12 One of
the potentially most useful and versatile functional groups to
be introduced is the formyl group. It is useful as a protecting
group which can be removed easily and selectively. Formate
esters can also serve as intermediates for C–C chain
2. Results and discussion
Compounds 1–9 (Scheme 1), having variable silyl protec-
tions at the primary positions, were studied for their direct
conversion into formates with the view to determining the
efficiency and the selectivity of the reaction (Scheme 2). We
opted only to study the reaction at the primary positions,
which are more reactive than the secondary ones. It had
Keywords: Carbohydrates; Vilsmeier–Haack (V–H) complex; Regio and
chemoselective O-formylation.
* Corresponding author. Tel.: C351-212948361; fax: C351-212948550;
e-mail: mtbarros@dq.fct.unl.pt
0040–4020/$ - see front matter q 2004 Elsevier Ltd. All rights reserved.
doi:10.1016/j.tet.2004.07.056

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M. M. Andrade, M. T. Barros / Tetrahedron 60 (2004) 9235–9243
Scheme 1. Preparation of silyl precursors of the sugars.
already been shown by Lellouche during studies with D-glucal
that the primary positions are preferred to the secondary ones,
even using large excess of the silylating agent,19 but the
regioselective conversion in a molecule with more that 1
primary position was not explored. The chemoselectivity
between TBDMS and TBDPS was also forgotten by the
authors, and the two were only compared in terms of speed of
reaction, and never used together in the same molecule.
substituted compound 3 was prepared by dropwise addition
of 1 equiv. of TBDPSCl to the sugar dissolved in dry
pyridine, using catalytical amount of DMAP, at room
temperature. The yield for this step was increased to 85%,
though the product did not need to be isolated and could be
immediately acetylated to afford 3 with an overall yield of
80%.
For the di-O-TBDPS protection, following the procedure
described by Khan,21 and contrary to his observations, we
obtained mainly the tri-protected derivative and only small
amounts of the desired di-protected compound. For this
reason, we modified the described method, heating sucrose
in pyridine (and catalytic DMAP) with 1.1 equiv. of
TBDPSCl at 70 8C for 4 h, followed by addition of another
1.1 equiv. of silylating agent at room temperature and 24h
stirring at room temperature. 6,60-Di-O-TBDPS-sucrose
was obtained with 84% yield. The product was sufficiently
pure to proceed without isolation, thus addition of acetic
anhydride to the reaction mixture, followed by column
purification afforded compound 4 in 78% overall yield.
2.1. Selective protection at the primary positions with
silyl ethers
Sugar derivatives 1 and 2 were prepared in one step from
methyl a-D-glucopyranoside with yields above 90%. Silyl
protection at the primary (6) position was achieved
according to described procedures,3 followed by acetylation
of the secondary hydroxyls with acetic anhydride.
Selective O-TBDPS protection for sucrose substrates 3–5
was carried out based upon Khan’s protocol,21 with slight
changes that permitted an increasing in the yields. Mono

M. M. Andrade, M. T. Barros / Tetrahedron 60 (2004) 9235–9243
9237
Scheme 2. Reaction of the sugar O-silylated precursors with 1.1 equiv. of POCl3$DMF.
Compound 5 was obtained in 75% yield from unprotected
sucrose in two steps by first adding 4.6 equiv. of TBDPSCl
to the solution containing sucrose and DMAP in anhydrous
pyridine and heating at 70 8C during 24 h, followed by
acetylation of the secondary positions and isolation by
column chromatography.
6), O-formylation was achieved with yields and times
comparable with those for the monosaccharide precursors.
When protected with TBDMS the precursors were converted
faster than in the case of the TBDPS ether (30 min vs. 24 h)
and with similar yield range (82 and 88% respectively). These
results were confirmed by 1H NMR spectroscopy, which gave
The TBDMS group is smaller and consequently less
hindered than the TBDPS, and so selective protection is
not so easy to achieve. Following the procedure of Franke,3
the O-TBDMS protected sucrose was obtained with
different degrees of protection and with variable yields.
The addition of 0.65 equiv. of TBDMSCl to a solution of
sucrose in pyridine and stirring overnight at room
temperature followed by acetylation with acetic anhydride
afforded a mixture of products, which includes the mono-,
di- and tri-protected products needed for our further
reactions. Column chromatography allowed the isolation
of compounds 6–8.
Table 1. Results obtained by O-formylation of the sugar substrates
Entry
Precursor
Time
24 h
5 min
24 h
24 h
Products obtained (yield)
10 (85%)
10 (84%)
11 R4ZCHO, R5ZR6ZAc (88%)
12 R4ZCHO, R5ZTBDPS, R6ZAc
(45%)
1
2
3
4
1
2
3
4
13 R4ZTBDPS, R5ZCHO, R6ZAc
(13%)
14 R4ZR5ZCHO, R6ZAc (5%)
4 recovered (22%)
5
5
24 h
15 R4ZCHO, R5ZR6ZTBDPS (59%)
16 R4ZR5ZCHO, R6ZTBDPS (16%)
5 recovered (21%)
Sucrose derivative 9 was obtained from 6,60-di-O-TBDPS-
sucrose by reaction in pyridine with 2 equiv. of TBDMSCl
in the presence of catalytical amount of DMAP, at room
temperature.22 This afforded 75% of 10-O-TBDMS-6,60-di-
O-TBDPS-sucrose, after column purification using ethyl
acetate/hexane 1:4. Acetylation with acetic anhydride in
pyridine gave 92% of 9.
6
7
8
6
7
7
30 min
30 min
5 min
11 R4ZCHO, R5ZR6ZAc (82%)
14 R4ZR5ZCHO, R6ZAc (77%)
17 R4ZCHO, R5ZTBDMS, R6ZAc
(15%)
18 R4ZTBDMS, R5ZCHO, R6ZAc
(18%)
14 R4ZR5ZCHO, R6ZAc (37%)
7 recovered (17%)
9
8
9
30 min
21 h
19 R4ZCHO, R5ZR6ZTBDMS (10%)
20 R4ZR6ZTBDMS, R5ZCHO (13%)
21 R4ZR5ZCHO, R6ZTBDMS (31%)
22 R4ZR5ZR6ZCHO (5%)
8 recovered (32%)
23 R4ZR5ZTBDPS, R6ZCHO (69%)
24 R4ZR6ZCHO, R5ZTBDPS (21%)
2.2. Vilsmeier–Haack (V–H) O-formylation
The monosaccharides 1 and 2 underwent formylation with
1.1 equiv. of the V–H reagent to afford the 6-formate ester
10 with good yields. As expected, the reaction was much
faster for the TBDMS protected compound (see Table 1,
entries 1 and 2).
10
All reactions were performed using 1.1 equiv. of POCl3; addition of V–H
complex was made dropwise to the sugar solution cooled with an ice bath;
the ice bath was then removed and the mixture maintained at RT for the
indicated time, except entries 8 and 9, where the reactions were carried out
at 0–5 8C.
The results obtained with sucrose require a closer examin-
ation. For the mono silylated substrates 3 and 6 (entries 3 and

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M. M. Andrade, M. T. Barros / Tetrahedron 60 (2004) 9235–9243
– The conversion of primary TBDMS ethers of sugars into
formates is much faster than for the TBDPS ethers (the
same trend is observed with glucose and sucrose).
– The O-formylation of TBDPS ethers of sucrose with
equimolar amount of POCl3$DMF is regioselective, and
the order of reactivity is 60O6[10. In fact, reaction at
position 10 was never observed.
– Very poor selectivity was found for the conversion of
primary TBDMS ethers of sucrose, and the0 reaction
occured at all three primary positions, that is, 6 Z6Z10.
a singlet at 8.15 ppm corresponding to the formate proton and
a deshielding of the protons at position 60 from 3.38 and 3.82
for 3 and 6, respectively to 4.43 ppm.
From these results we can conclude that the O-formylation
of TBDMS ethers with equimolar amount of POCl3 is much
faster than with TBDPS ethers (some minutes versus one
day).
The challenge now was to convert one silyl ether group
selectively in the presence of others. For the di- and tri-O-
TBDMS protected sucrose compounds 7 and 8 respectively,
this objective failed. Reaction of 7 with 1.1 equiv. of POCl3
at room temperature afforded uniquely the diformylated
compound 14 (entry 7) after 30 min reaction at room
temperature in 77% yield. By lowering the temperature to
0 8C (entry 8), we obtained after 5 min, a mixture which
contained the mono formylated compounds 17 and 18 in
low yields, 37% of diformate 14 and 17% of the starting
sugar recovered. Increasing the time of reaction led to the
formation of more diformylated derivative. In an attempt
to improve the results, the reaction was also carried out at
K50 8C, but all the starting material was recovered after
2 h.
Bearing in mind these results, we expected that it would be
possible to convert selectively TBDMS ethers to formates in
the presence of TBDPS ethers. In order to verify this, we
prepared compound 9, with two TBDPS groups in the
positions 6 and 60, and TBDMS group in the most hindered
position 10. Using 1.1 equiv. of POCl3 to generate the V–H
reagent (entry 10) we obtained 69% of formate 23,
corresponding to the conversion at the hindered position
10. 1H NMR of this compound showed a singlet at 8.05 ppm
which was assigned to the formate proton; the signals
corresponding to the methyl group of TBDMS had
disappeared and the aromatic protons from TBDPS were
still present, together with a singlet at 1.02 ppm correspond-
ing to 18 protons of the tert-butyl groups. The 10 protons,
which appeared at 3.84 and 3.55 ppm in 10, were deshielded
to 4.30 ppm in the product 23. As a secondary product, we
The assignment of the structures was made by 2 dimen-
sional NMR studies (HMQC and COSY). For compound 7
the chemical shift in the 01H NMR for the C(6) protons was
3.81 ppm and for the C(6 ), 3.70 ppm. For compound 17, the
formyl proton appeared at 8.14 ppm and the 60 protons were
shifted to 4.40 ppm; for compound 18, the singlet
corresponding to the formyl appeared at 8.06 and C(6)
protons were deshielded to 4.26 ppm. Slight shifts for 5 and
50 protons were also be observed and supported these
results. For compound 14, the two formyl singlets appeared
at 8.09 and 8.12 ppm.
obtained 22% of 24, resulting from reaction at positions 10
0
0
0
and 6 (10: d6 Z3.78 ppm; 24: d6 Z4.34 ppm, dCHOZ8.06
and 8.05 ppm). We were never able to eliminate this
unwanted transformation, even making the formylation at
lower temperatures.
From these results we can finally conclude that the
O-formylation of the silyl ethers in primary positions of
sucrose with equimolar amount of POCl3$DMF is chemo-
selective, and TBDMS ethers are more reactive than
TBDPS ethers.
Attempts to selectively formylate the trisilylated precursor 8
were also unsuccessful (entry 9). A complex mixture of
products was obtained after 30 min of reaction, from
which were isolated and characterized the mono-, di- and
triformylated compounds 19–22, with very poor yields.
Lowering the temperature did not change the results. When
the reaction was left for a longer time (21 h), the formation
of more diformylated compound and disappearance of the
mono derivatives was observed.
3. Experimental
3.1. General
All solvents were purified before use.23 POCl3 was distilled
immediately before use. All reactions were run under dry
argon atmosphere. All reactions were monitored by thin
layer chromatography, which was performed on aluminium-
backed silica gel Merck 60 F254 plates, and compounds were
detected by ultraviolet light or by staining with 10%
solution of H2SO4 in ethanol followed by heating. Flash
chromatography was carried out using silica gel from
Macherey–Nagel (Kieselgel 60 M). Preparative layer chro-
matography was performed on glass plates coated with
1 mm of silica gel (Mackerey–Nagel, Kieselgel DGF254).
Melting points were determined with a capillary apparatus
and are uncorrected. Elemental analyses were performed on
Thermo Finnigan-CE Flash EA 1112 CHNS series analyser.
Mass spectra were determined on a GCT Micromass
spectrometer. NMR spectra were recorded on a Bruker
AMX-400 MHz apparatus in CDCl3, using TMS as internal
standard, with chemical shift values (d) in ppm and coupling
Fortunately, better results were obtained when sucrose was
protected with TBDPS. Adding 1.1 equiv. of Vilsmeier–
Haack reagent to disilylated compound 4 (entry 4), formate
12 (45%) was formed as major product, with the formate
0
0
0
ester group at position 6 (4: d6 Z3.80 ppm; 12: d6 Z
4.33 ppm, dCHOZ8.03 ppm). Formylation at position 6 also
occured but at lesser extent (13%) to give 13 (4: d6Z
3.56 ppm; 13: d6Z4.41 ppm, dCHOZ8.15 ppm).
The same trend was observed with the tri-O-TBDPS ether 5
(entry 5). By addition of 1.1 equiv. of the formylating agent
0
0
was obtained 59% of 15, formylated at position 6 (5: d6 Z
0
3.79 ppm; 15: d6 Z4.30 ppm, dCHOZ8.03 ppm), as well as
16% of compound 16 and 21% of starting sugar 4 recovered.
From these results we can conclude:

M. M. Andrade, M. T. Barros / Tetrahedron 60 (2004) 9235–9243
9239
constants in Hertz (Hz). Optical rotations were measured at
20 8C onan Optical Activity AA-1000polarimeterat 589 nm.
(C-10), 61.57 (C-6), 26.71 (CH3 (tBu)), 20.56 (CH3 (Ac)),
19.10 (C (tBu)) ppm.
3.2. General method for preparation of the silyl
compounds
3.2.4. 10,2,3,30,4,40-Hexa-O-acetyl-6,60-di-O-TBDPS-
sucrose (4). To a solution of sucrose (5 g, 0.015 mol) in
pyridine (90 mL), was added tert-butyldiphenyl-chloro-
silane (4.2 mL, 1.1 equiv.) in the presence of catalytical
amount of DMAP, followed by 4 h heating at 70 8C. After
cooling, the same amount of TBDPSCl was added, and the
reaction was kept at room temperature for 24 h. Evaporation
of the solvent and flash chromatography with ethyl acetate
gave 6,60-di-O-TBDPS sucrose (10.05 g) with 84% yield.
Acetylation with acetic anhydride followed by column
purification with hexane/ethyl acetate 1:1 afforded 4 with
Compounds 1–9 were prepared based on the literature
procedures, with some changes when mentioned (1, 2, 6–8;3
3–5,21 922).
3.2.1. Methyl 2,3,4-tri-O-acetyl-6-O-TBDPS-a-D-gluco-
pyranose (1). Compound 1 (2.62 g) was prepared from
methyl a-D-glucopyranose (1 g, 5.15 mmol) in 91% yield,
and purified by flash chromatography with hexane/ether 1:4.
1H NMR (CDCl3) d 7.68 (m, 4H, Ph–Hortho), 7.41 (m, 6H,
Ph–Hmeta,para), 5.47 (t, 1H, JZ9.8 Hz, H-3), 5.08 (t, 1H, JZ
9.8 Hz, H-4), 4.97 (d, 1H, JZ3.6 Hz, H-1), 4.89 (dd, 1H,
1
78% of overall yield (12.2 g) H NMR (CDCl3) d 7.63 (m,
8H, Ph–Hortho), 7.35 (m, 12H, Ph–Hmeta,para), 5.65 (d, 1H,
JZ3.5 Hz, H-1), 5.42 (t, 1H, JZ4.6 Hz, H-40), 5.41 (t, 1H,
JZ9.6 Hz, H-3), 5.35 (t, 1H, JZ9.7 Hz, H-4), 5.31 (d, 1H,
JZ4.2 Hz, H-30), 4.82 (dd, 1H, J1,2Z3.5 Hz, J2,3Z10 Hz,
H-2), 4.30 (d, 1H, JZ12.4 Hz, H-10a), 4.23 (d, 1H, JZ
12.4 Hz, H-10b), 4.06 (q, 1H, JZ5.6 Hz, H-50), 4.00 (bd,
J1,2Z3.6 Hz, J2,3Z10.2 Hz, H-2), 3.87 (ddd, 1H, J4,5
Z
10.1 Hz, J5,6bZ4.8 Hz, J5,6aZ2.5 Hz, H-5), 3.70 (m, 2H,
H-6), 3.41 (s, 1H, OCH3), 2.084, 2.001, 1.884 (3s, 9H,
t
3O]C–OCH3), 1.053 (s, 9H, Bu–H) ppm. 13C NMR
0
0
1H, JZ9.9 Hz, H-5), 3.83 (dd, 1H, J5 ,6 aZ5.2 Hz,
(CDCl3) d 170.16 (C]O), 135.62, 135.58 (C–Hortho (Ph)),
133.08 (C (Ph)), 129.68, 129.64 (C–Hpara (Ph)), 127.64
(C–Hmeta (Ph)), 96.45 (C-1), 71.00 (C-2), 70.51 (C-3), 69.87
(C-5), 68.89 (C-4), 62.61 (C-6), 55.06 (OCH3), 26.65 (CH3
(tBu)), 20.72, 20.67, 20.51 (CH3 (Ac)), 19.13 (C (tBu)) ppm.
J6 a,6 bZ10.5 Hz, H-60a), 3.77 (dd, 1H, J5 ,6 bZ7 Hz,
0
0
0
0
J6 a,6 bZ10.8 Hz, H-60b), 3.61 (d, 1H, J5,6aZ11.2 Hz,
H-6a), 3.51 (dd, 1H, J5,6bZ2.4 Hz, J6a,6bZ11.5 Hz, H-6b),
2.11, 2.09, 2.07, 2.04, 2.03, 1.84 (6s, 18H, 6OCH3), 1.01 (s,
18H, 2tBu–H) ppm. 13C NMR (CDCl3) d 170.26, 170.14,
169.63, 169.12 (C]O), 135.65, 135.47 (C–Hortho (Ph)),
133.15, 132.97 (C (Ph)), 129.74, 129.63 (C–Hpara (Ph)),
127.70, 127.63 (C–Hmeta (Ph)), 104.56 (C-20), 90.57 (C-1),
81.93 (C-50), 76.22 (C-30), 75.18 (C-40), 70.65 (C-5), 70.57
(C-3), 70.20 (C-2), 68.02 (C-4), 63.90 (C-60), 62.22 (C-10),
61.31 (C-6), 26.69 (CH3 (tBu)), 20.75, 20.59, 20.49 (CH3
(Ac)), 19.14 (C (tBu)) ppm.
0
0
3.2.2. Methyl 2,3,4-tri-O-acetyl-6-O-TBDMS-a-D-gluco-
pyranose (2). Compound 2 (2.20 g) was prepared from
methyl a-D-glucopyranose (1 g, 5.15 mmol) in 98% yield,
and purified by flash chromatography with hexane/ether 1:4.
1H NMR (CDCl3) d 5.45 (t, 1H, JZ9.8 Hz, H-3), 5.00 (t,
1H, JZ9.8 Hz, H-4), 4.92 (d, 1H, JZ3.6 Hz, H-1), 4.85 (dd,
1H, J1,2Z3.6 Hz, J2,3Z10.2 Hz, H-2), 3.80 (ddd, 1H, J4,5
Z
10.1 Hz, J5,6bZ4.8 Hz, J5,6aZ2.5 Hz, H-5), 3.74 (m, 2H,
H-6), 3.385 (s, 1H, OCH3), 2.06, 2.00, 1.99 (3s, 9H,
3.2.5. 10,6,60-Tri-O-TBDPS-2,3,30,4,40-penta-O-acetyl-
sucrose (5). Compound 5 (13.89 g) was prepared from
sucrose (5 g, 0.019 mol) in 75% yield, and purified by flash
t
3O]C–OCH3), 0.88 (s, 9H, Bu–H), 0.032, K0.017 (Si–
(CH3)2) ppm. 13C NMR (CDCl3) d 170.22 (C]O), 135.62,
96.48 (C-1), 71.01 (C-2), 70.53 (C-3), 69.88 (C-5), 69.08
(C-4), 62.21 (C-6), 55.11 (OCH3), 25.83 (CH3 (tBu)), 20.71
(CH3 (Ac)), 18.28 (C (tBu)), K5.76 (Si–CH3) ppm.
1
chromatography with hexane/ethyl acetate 2:1. H NMR
(CDCl3) d 7.63 (m, 12H, Ph–Hortho), 7.30 (m, 18H, Ph–
Hmeta,para), 5.84 (d, 1H, JZ6.2 Hz, H-30), 5.60 (d, 1H, JZ
3.6 Hz, H-1), 5.39 (t, 1H, JZ6.4 Hz, H-40), 5.37 (t, 1H, JZ
9.5 Hz, H-4), 5.32 (t, 1H, JZ9.6 Hz, H-3), 4.85 (dd, 1H,
J1,2Z3.7 Hz, J2,3Z9.7 Hz, H-2), 4.12 (q, 1H, JZ6.2 Hz,
3.2.3.
10,2,3,30,4,40,6-Hepta-O-acetyl-60-O-TBDPS-
sucrose (3). Compound 3 (9.36 g) was prepared from
sucrose (5 g, 0.015 mol) and 3.8 mL (1 equiv.) of
TBDPSCl, followed by conventional acetylation with acetic
anhydride, in 73% overall yield. It was purified by flash
H-50), 3.98 (bd, 1H, JZ9.4 Hz, H-5), 3.84 (dd, 1H, J5 ,6 b
Z
Z
0
0
5.8 Hz, J6 a,6 bZ11 Hz, H-60b), 3.75 (dd, 1H, J5 ,6 a
0
0
0
0
5.1 Hz, J6 a,6 bZ11.3 Hz, H-60a), 3.78 (d, 1H, JZ10.9 Hz,
H-10a), 3.58 (d, 1H, J5,6aZ11.4 Hz, H-6a), 3.50 (dd, 1H,
J5,6bZ2.2 Hz, J6a,6bZ11.6 Hz, H-6b), 3.51 (d, 1H, JZ
10.8 Hz, H-10b), 2.02, 1.98, 1.92, 1.85, 1.80 (5s, 15H,
5OCH3), 1.08, 1.02, 0.99 (3s, 27H, 3tBu–H) ppm. 13C NMR
(CDCl3) d 170.26, 170.14, 169.63, 169.12 (C]O), 135.65,
135.47 (C–Hortho (Ph)), 133.15, 132.97 (C (Ph)), 129.74,
129.63 (C–Hpara (Ph)), 127.70, 127.63 (C–Hmeta (Ph)),
104.56 (C-20), 90.57 (C-1), 81.93 (C-50), 76.22 (C-30),
75.18 (C-40), 70.65 (C-5), 70.57 (C-3), 70.20 (C-2), 68.02
(C-4), 63.90 (C-60), 62.22 (C-10), 61.31 (C-6), 26.69 (CH3
(tBu)), 20.75, 20.59, 20.49 (CH3 (Ac)), 19.14 (C (tBu)) ppm.
0
0
1
chromatography with hexane/ethyl acetate 1:1. H NMR
(CDCl3) d 7.64 (m, 4H, Ph–Hortho), 7.34 (m, 6H, Ph–
Hmeta,para), 5.63 (d, 1H, JZ3.6 Hz, H-1), 5.51 (t, 1H, JZ
5.8 Hz, H-40), 5.39 (d, 1H, JZ5.4 Hz, H-30), 5.38 (t, 1H, JZ
8.8 Hz, H-3), 5.01 (t, 1H, JZ9.8 Hz, H-4), 4.81 (dd, 1H,
J1,2Z3.7 Hz, J2,3Z10.3 Hz, H-2), 4.17 (d, 1H, JZ12.1 Hz,
H-10a0), 4.12 (d, 1H, JZ12.4 Hz, H-10b), 4.16 (m, 3H,
H-5,5 ,6b), 3.92 (dd, 1H, J5,6aZ1.4 Hz, J6a,6bZ7.8 Hz,
H-6a), 3.85 (dd, 1H, J5 ,6 aZ5.1 Hz, J6 a,6 bZ11 Hz, H-60a),
0
0
0
0
3.82 (dd, 1H, J5 ,6 bZ5.6 Hz, J6 a,6 bZ11 Hz, H-60b), 2.14,
2.10, 2.09, 2.05, 2.01, 1.98, 1.97 (7s, 21H, 7OCH3), 1.06 (s,
0
0
0
0
t
9H, Bu–H) ppm. 13C NMR (CDCl3) d 170.00, 169.76
(C]O), 135.57 (C–Hortho (Ph)), 132.9 (C (Ph)),0 129.85
(C–Hpara (Ph)), 127.78 (C–Hmeta (Ph)), 103.67 (C-2 ), 89.70
(C-1), 81.38 (C-50), 76.19 (C-30), 75.11 (C-40), 70.20 (C-2),
69.78 (C-3), 68.27 (C-5), 68.09 (C-4), 63.83 (C-60), 62.90
3.2.6.
10,2,3,30,4,40,6-Hepta-O-acetyl-60-O-TBDMS-
sucrose (6), 10,2,3,30,4,40-hexa-O-acetyl-6,60-di-O-TBDMS-
sucrose (7) and 10,6,60-tri-O-TBDMS-2,3,30,4,40-penta-O-
acetyl-sucrose (8). Reaction of sucrose (5 g, 0,019 mol)

9240
M. M. Andrade, M. T. Barros / Tetrahedron 60 (2004) 9235–9243
with TBDMSCl (0.65 equiv.), followed by acetylation gave,
after column chromatography with hexane/ethyl acetate 2:1
and 1:1, compounds 6 (1.21 g, 11%), 7 (4.09 g, 34%) and 8
5.3 Hz, H-40), 4.88 (dd, 1H, J1,2Z3.6 Hz, J2,3Z9.8 Hz,
H-2), 4.10 (m, 1H, JZ7.1 Hz, H-5), 3.99 (q, 1H, JZ5.5 Hz,
H-50), 3.84 (d, 1H, JZ11 Hz, H-10a), 3.81 (dd, 1H, J5 ,6 b
Z
Z
Z
Z
0
0
1
5.6 Hz, J6 a,6 bZ10.9 Hz, H-60b), 3.76 (dd, 1H, J5 ,6 a
0
0
0
0
(4.58 g, 35%). 6: H NMR (CDCl3) d 5.73 (d, 1H, JZ
3.6 Hz, H-1), 5.45 (t, 1H, JZ5.3 Hz, H-400), 5.44 (t, 1H, JZ
9.9 Hz, H-3), 5.41 (d, 1H, JZ6.0 Hz, H-3 ), 5.07 (t, 1H, JZ
9.8 Hz, H-4), 4.85 (dd, 1H, J1,2Z3.6 Hz, J2,3Z10.4 Hz,
H-2), 4.28 (m, 1H, H-5), 4.26 (dd, 1H, J5,6aZ4.1 Hz,
J6a,6bZ11.6 Hz, H-6a), 4.20 (d, 1H, JZ12.4 Hz, H-10a),
5.4 Hz, J6 a,6 bZ10.9 Hz, H-60a), 3.69 (dd, 1H, J5,6a
1.2 Hz, J6a,6bZ11.7 Hz, H-6a), 3.58 (dd, 1H, J5,6b
0
0
2.4 Hz, J6a,6bZ9.9 Hz, H-6b), 3.55 (d, 1H, JZ10.9 Hz,
H-10b), 2.08, 2.02, 2.01, 1.98, 1.84 (5s, 15H, 5OCH3), 1.02
(s, 18H, 2tBu–H (TBDPS)), 0.91 (s, 9H, tBu–H (TBDMS)),
0.08, 0.07 (d, 6H, Si–(CH3)2) ppm. 13C NMR (CDCl3) d
170.09, 169.61 (C]O), 135.66, 135.53 (C–Hortho(Ph)),
133.09 (C (Ph)), 129.68 (C–Hpara(Ph)), 127.68 (C–Hmeta
(Ph)), 105.53 (C-20), 90.24 (C-1), 81.43 (C-50), 76.02, 76.01
(C-300,40), 70.57, 70.44, 70.32 (C-3,2,5), 68.18 (C-4), 64.13
(C-6 ), 63.36 (C-10), 61.45 (C-6), 26.70, 25.75 (CH3
(tBu)), 20.80, 20.66, 20.56 (CH3 (Ac)), 19.18 (C
(tBu)), K5.52, K5.63, K5.97 (Si–CH3) ppm. Anal.
Calcd for C60H82O16Si3: C, 63.02; H, 7.23. Found: C,
62.80; H, 7.28.
4.15 (d, 1H, JZ12.6 Hz, H-10b), 4.12 (dd, 1H, J5,6b
Z
4.8 Hz, J6a,6bZ12.6 Hz, H-6b), 4.05 (q, 1H, JZ5.5 Hz,
H-50), 3.84 (dd, 1H, J5 ,6 aZ1.6 Hz, J6 a,6 bZ11 Hz, H-60a),
0
0
0
0
3.80 (dd, 1H, J5 ,6 bZ2.3 Hz, J6 a,6 bZ11.1 Hz, H-60b),
2.13, 2.09, 2.07, 2.06, 2.02, 2.00 (6s, 21H, 7OCH3), 0.89 (s,
0
0
0
0
t
9H, Bu–H), 0.083, 0.077 (2s, 6H, 2Si–(CH3)2) ppm. 130C
NMR (CDCl3) d 170.68, 170.11 (C]O), 103.80 (C-2 ),
89.77 (C-1), 81.52 (C-50), 76.24 (C-30), 75.07 (C-40), 70.26
(C-2), 69.70 (C-3), 68.25 (C-4,5), 63.31 (C-60), 62.87 (C-
10), 61.68 (C-6), 25.80 (CH3 (tBu)), 20.75, 20.64 (CH3
1
(Ac)), 18.30 (C (tBu)), K5.53 (Si–CH3) ppm. 7: H NMR
(CDCl3) d 5.67 (d, 1H, JZ3.5 Hz, H-1), 5.43 (t, 1H, JZ
10.1 Hz, H-3), 5.40 (t, 1H, JZ5.5 Hz, H-40), 5.38 (d, 1H,
JZ5.6 Hz, H-30), 5.17 (t, 1H, JZ9.8 Hz, H-4), 4.82 (dd,
1H, J1,2Z3.6 Hz, J2,3Z10.4 Hz, H-2), 4.21 (d, 1H, JZ
12.5 Hz, H-10a), 4.18 (d, 1H, JZ12.5 Hz, H-10b), 4.11 (m,
1H, H-5), 4.06 (q, 1H, JZ5.9 Hz, H-50), 3.84 (dd, 1H,
3.3. General method for Vilsmeier–Haack (V–H)
formylation
Freshly distilled phosphorus oxychloride (1.1 equiv.) was
dissolved in cold DMF (1 mL) (cooled with an ice bath) and
stirred during 30 min at 0–5 8C. The sugar (1 mmol) was
dissolved in DMF (2 mL) and cooled in an ice bath. The
V–H complex was then added dropwise to the sugar solution
and the reaction was stirred at room temperature or at
0–5 8C for the indicated time (see Table 1). Hydrolysis was
achieved by adding 30 mL of saturated solution of NaHCO3
at 0–5 8C. The aqueous layer was extracted with ether and
washed with water. The combined organic layers were dried
over Na2SO4 and the solvent was distilled off. The crude
was purified by flash chromatography to afford the O-formyl
derivatives.
J5,6aZ5.6 Hz, J6a,6bZ10.6 Hz, H-6a), 3.78 (dd, 1H, J5,6b
6.3 Hz, J6a,6bZ10.5 Hz, H-6b), 3.73 (dd, 1H, J5 ,6 a
Z
Z
Z
0
0
1.7 Hz, J6 a,6 bZ11.5 Hz, H-60a), 3.68 (dd, 1H, J5 ,6 b
0
0
0
0
3.3 Hz, J6 a,6 bZ11.5 Hz, H-60b), 2.12, 2.09, 2.09, 2.03,
2.00 (5s, 18H, 6OCH3), 0.89, 0.87 (2s, 18H, 2tBu–H), 0.09,
0.08, 0.02, 0.02 (4s, 12H, 2Si–(CH3)2) ppm. 13C NMR
(CDCl3) d 170.20, 169.83, 169.21 (C]O), 103.94 (C-20),
90.17 (C-1), 81.53 (C-50), 76.41 (C-30), 75.61 (C-40), 70.54
(C-5), 70.43 (C-2), 70.20 (C-3), 68.46 (C-4), 63.69 (C-6),
62.85 (C-10), 61.44 (C-60), 25.84 (CH3 (tBu)), 20.64 (CH3
0
0
1
(Ac)), 18.32 (C (tBu)), K5.55 (Si–CH3) ppm. 8: H NMR
(CDCl3) d 5.68 (d, 1H, JZ3.5 Hz, H-1), 5.62 (d, 1H, JZ
6.6 Hz, H-300), 5.43 (t, 1H, JZ9.8 Hz, H-3), 5.42 (t, 1H, JZ
6.2 Hz, H-4 ), 5.19 (t, 1H, JZ9.8 Hz, H-4), 4.84 (dd, 1H,
J1,2Z3.6 Hz, J2,3Z10.3 Hz, H-2), 4.12 (bd, 1H, JZ9.4 Hz,
3.3.1. Methyl 2,3,4-tri-O-acetyl-6-O-formyl-a-D-gluco-
pyranose (10). Column chromatography with hexane/
ether 1:4 followed by crystallization from ether afforded
10 (296 mg, 85% starting from 1; 292.6 mg, 84% starting
from 2) as colourless needles; mp 89–90 8C. [a]2D0ZC136.4
(c 1.0, CHCl3). H NMR (CDCl3) d 8.09 (s, 1H, HC]O),
5.49 (t, 1H, JZ9.6 Hz, H-3), 5.06 (t, 1H, JZ10 Hz, H-4),
4.96 (d, 1H, JZ3.6 Hz, H-1), 4.89 (dd, 1H, J1,2Z3.6 Hz,
H-5), 3.99 (q, 1H, JZ5.4 Hz, H-50), 3.80 (m, 2H, J5 ,6 a
Z
0
0
1.6 Hz, J6 a,6 bZ12.4 Hz, H-60a,60b), 3.76 (d, 1H, JZ
1
0
0
11 Hz, H-10a), 3.74 (bs, 1H, H-6b), 3.70 (dd, 1H, J5,6a
Z
2.5 Hz, J6a,6bZ11.4 Hz, H-6a), 3.50 (d, 1H, JZ11 Hz, H-
10b), 2.09, 2.06, 2.03, 2.00 (4s, 15H, 5OCH3), 0.90, 0.89,
0.88 (3s, 27H, 3tBu–H), 0.08, 0.07, 0.06, 0.03, 0.02 (5s,
18H, 3Si–(CH3)2) ppm. 13C NMR (CDCl3) d 169.97, 169.26
(C]O), 104.98 (C-20), 89.65 (C-1), 81.02 (C-50), 75.68
(C-30), 75.40 (C-40), 700.57 (C-3), 70.33 (C-2), 70.22 (C-5),
68.62 (C-4), 63.73 (C-1 ,60), 61.52 (C-6), 25.88, 25.82 (CH3
(tBu)), 20.67 (CH3 (Ac)), 18.26 (C (tBu)), K5.492, K5.543,
K5.617 (Si–CH3) ppm.
J2,3Z10 Hz, H-2), 4.28 (m, 2H, H-6), 4.03 (ddd, 1H, J4,5
Z
10.4 Hz, J5,6bZ4.8 Hz, J5,6aZ2.2 Hz, H-5), 3.43 (s, 1H,
OCH3), 2.08, 2.04, 2.01 (3s, 9H, 3O]C–OCH3) ppm. 13C
NMR (CDCl3) d 170.04, 169.58 (H3CC]O), 160.37
(HC]O), 96.74 (C-1), 70.72 (C-2), 69.97 (C-3), 68.67
(C-4), 66.94 (C-5), 61.48 (C-6), 55.52 (OCH3), 20.65 (CH3
(Ac)) ppm. Anal. Calcd for C14H20O10: C, 48.28; H, 5.79.
Found: C, 48.33; H, 5.81.
3.2.7. 10-O-TBDMS-6,60-di-O-TBDPS-2,3,30,4,40-penta-
O-acetyl-sucrose (9). Compound 9 (1.69 g) was prepared
from 6-60-di-O-TBDPS sucrose (1.78 g, 2.17 mmol), fol-
lowed by acetilation, in 68% yield and purified by flash
chromatography with hexane/ethyl acetate 2:1. [a]2D0Z
C58.0 (c 1.0, CHCl3). 1H NMR (CDCl3) d 7.63 (m, 8H, Ph–
Hortho), 7.34 (m, 12H, Ph–Hmeta,para), 5.64 (d, 1H, JZ
3.6 Hz, H-1), 5.57 (d, 1H, JZ5.1 Hz, H-30), 5.44 (t, 1H, JZ
9.7 Hz, H-3), 5.38 (t, 1H, JZ9.2 Hz, H-4), 5.37 (t, 1H, JZ
3.3.2. 10,2,3,30,4,40,6-Hepta-O-acetyl-60-O-formyl-sucrose
(11). Column chromatography with hexane/ethyl acetate 1:1
afforded 11 (584.8 mg, 88% starting from 3; 544.9 mg, 82%
starting from 6) as colourless oil. [a]2D0Z C62.8 (c 1.0,
CHCl3). 1H NMR (CDCl3) d 8.15 (s, 1H, HC]O), 5.65 (d,
1H, JZ3.5 Hz, H-1), 5.48 (d, 1H, JZ6.5 Hz, H-300), 5.47 (t,
1H, JZ9.6 Hz, H-3), 5.40 (t, 1H, JZ6.2 Hz, H-4 ), 5.06 (t,
1H, JZ9.8 Hz, H-4), 4.88 (dd, 1H, J1,2Z3.6 Hz, J2,3
Z
Z
0
0
0
0
10.4 Hz, H-2), 4.48 (dd, 1H, J5 ,6 aZ3.8 Hz, J6 a,6 b

M. M. Andrade, M. T. Barros / Tetrahedron 60 (2004) 9235–9243
9241
12 Hz, H-60a), 4.39 (dd, 1H, J5 ,6 bZ6.5 Hz, J6 a,6 b
Z
CHCl3). 1H NMR (CDCl3) d 8.13, 8.11 (2s, 2H,
2HC]O), 5.66 (d, 1H, JZ3.6 Hz, H-1), 5.49 (d, 1H, JZ
6.4 Hz, H-300), 5.47 (t, 1H, JZ10.7 Hz, H-3), 5.41 (t, 1H, JZ
6.4 Hz, H-4 ), 5.05 (t, 1H, JZ9.8 Hz, H-4), 4.88 (dd, 1H,
0
0
0
0
12 Hz, H-60b), 4.26 (m, 3H, H-5,50,6b), 4.22 (d, 1H, JZ
12.2 Hz, H-10a), 4.17 (d, 1H, JZ12 Hz, H-10b), 4.15 (dd,
1H, J5,6aZ1.4 Hz, J6a,6bZ12 Hz, H-6a), 2.17, 2.12, 2.11,
2.05, 2.02 (6s, 21H, 7OCH3) ppm. 13C NMR (CDCl3) d
170.66, 170.00, 169.65, 169.49 (H3CC]O), 160.45
(HC]O), 103.85 0(C-20), 90.21 (C-1), 78.69 (C-50), 75.62
(C-30), 74.68 (C-4 ), 70.022 (C-2), 69.46 (C-3), 68.46 (C-5),
68.22 (C-4), 62.89 (C-6 ), 62.70 (C-6), 61.82 (C-10), 20.59
(CH3 (Ac)) ppm. Anal. Calcd for C27H36O19: C 48.80, H
5.46. Found: C 48.78, H 5.41.
0
0
J1,2Z3.6 Hz, J2,3Z10.4 Hz, H-2), 4.47 (dd, 1H, J5 ,6 a
Z
Z
3.9 Hz, J6 a,6 bZ12.1 Hz, H-60a), 4.40 (dd, 1H, J5 ,6 b
0
0
0
0
6.5 Hz, J6 a,6 bZ12.1 Hz, H-60b), 4.28 (m, 4H, H-
5,6a,6b,50), 4.200 (d, 1H, JZ12.3 Hz, H-10a), 4.14 (d, 1H,
JZ12.2 Hz, H-1 b), 2.18, 2.12, 2.11, 2.06, 2.02 (5s, 18H,
6OCH3) ppm. 13C NMR (CDCl3) d 170.02, 169.71
(H3CC]O), 160.53, 160.44 (HC]O), 103.64 (C-20),
89.94 (C-1), 78.61 (C-50), 75.52 (C-30), 74.50 (C-40),
70.12 (C-2),0 69.40 (C-3), 68.40 (C-4), 68.30 (C-5),
62.92 (C-10,6 ), 61.30 (C-6), 20.60 (CH3 (Ac)) ppm. Anal.
Calcd for C26H34O19: C 48.00, H 5.27. Found: C 48.22, H
5.32.
0
0
3.3.3. 10,2,3,30,4,40-Hexa-O-acetyl-6-O-TBDPS-60-O-for-
myl-sucrose (12), 10,2,3,30,4,40-hexa-O-acetyl-6-O-
formyl-60-O-TBDPS-sucrose (13) and 10,2,3,30,4,40-
hexa-O-acetyl-6,60-di-O-formyl-sucrose (14). Prepared
from 4. Column chromatography with hexane/ethyl acetate
1:1 afforded 12 (387.4 mg, 45%, colourless oil), 13
(111.9 mg, 13%, colourless oil), 14 (32.5 mg, 5%, colour-
less needles) and 4 recovered (235.7 mg, 22%). 12:
[a]2D0ZC67.8 (c 1.0, CHCl3). 1H NMR (CDCl3) d 8.03 (s,
1H, HC]O), 7.65 (m, 4H, Ph–Hortho), 7.34 (m, 6H, Ph–
Hmeta,para), 5.67 (d, 1H, JZ3.5 Hz, H-1), 5.67 (t, 1H, JZ
9.9 Hz, H-3), 5.41 (d, 1H, JZ5.9 Hz, H-30), 5.34 (t, 1H, JZ
9.8 Hz, H-4), 5.32 (t, 1H, JZ6.8 Hz, H-40), 4.87 (dd, 1H,
3.3.4. 10,6-Di-O-TBDPS-2,3,30,4,40-penta-O-acetyl-60-O-
formyl-sucrose (15) and 10-O-TBDPS-2,3,30,4,40-penta-
O-acetyl-6,60-di-O-formyl-sucrose (16). Prepared from 5.
Column chromatography with hexane/ethyl acetate 2:1
afforded 15 (623.8 mg, 59%, colourless oil), 16 (135.5 mg,
16%, colourless oil) and 5 recovered (266.2 mg, 21%). 15:
[a]2D0ZC72.0 (c 1.0, CHCl3). 1H NMR (CDCl3) d 8.04 (s,
1H, HC]O), 7.64 (m, 8H, Ph–Hortho), 7.36 (m, 12H,
Ph–Hmeta,para), 5.90 (d, 1H, JZ7 Hz, H-30), 5.56 (d, 1H, JZ
0
0
J1,2Z3.5 Hz, J2,3Z10.3 Hz, H-2), 4.37 (dd, 1H, J5 ,6 a
Z
3.9 Hz, J6 a,6 bZ11.8 Hz, H-60a), 4.28 (d, 1H, JZ12.1 Hz,
3.6 Hz, H-1), 5.39 (m, 3H, H-4,3,40), 4.84 (dd, 1H, J1,2
Z
0
0
H-10a), 4.26 (dd, 1H, J5 ,6 bZ6.6 Hz, J6 a,6 bZ11.5 Hz,
H-60b), 4.20 0(m, 1H, JZ5.7 Hz, H-50), 4.16 (d, 1H, JZ
12.3 Hz, H-1 b), 4.09 (bd, 1H, J4,5Z9.8 Hz, H-5), 3.74 (d,
1H, J6a,6bZ11.8 Hz, H-6a), 3.68 (dd, 1H, J5,6bZ2.9 Hz,
J6a,6bZ11.7 Hz, H-6b), 2.12, 2.10, 2.09, 2.08, 2.03, 1.93
3.7 Hz, J2,3Z9.5 Hz, H-2), 4.38 (dd, 1H, J5 ,6 aZ1.9 Hz,
0
0
0
0
0
0
J6 a,6 bZ10.9 Hz, H-60a), 4.21 (m, 2H, H-50,60b), 4.03 (bd,
0
0
1H, J4,5Z8.7 Hz, H-5), 3.77 (d, 1H, JZ10.8 Hz, H-10a),
3.67 (d, 1H, J6a,6bZ11.4 Hz, H-6a), 3.63 (dd, 1H, J5,6b
Z
1.9 Hz, J6a,6bZ11.7 Hz, H-6b), 3.49 (d, 1H, JZ10.8 Hz,
H-10b), 2.06, 2.03, 1.99, 1.92, 1.76 (5s, 15H, 5OCH3), 1.06,
1.03 (2s, 18H, 2tBu–H) ppm. 13C NMR (CDCl3) d 170.42,
169.96, 169.75, 169.15 (H3CC]O), 160.47 (HC]O),
135.62 (C–Hortho (Ph)), 133.15, 132.97, 132.58 (C (Ph)),
129.92, 129.83, 129.67, 129.58 (C–Hpara (Ph)), 0 127.85,
127.74, 127.65, 127.60 (C–Hmeta (Ph)), 105.13 (C-2 ), 90.04
(C-1), 78.03 (C-50), 75.20 (C-30), 74.82 (C-40), 70.48 (C-3),
70.37 (C-5), 70.24 (C-2), 68.09 (C-4), 64.12 (C-10), 62.80
(C-60), 61.36 (C-6), 26.72 (CH3 (tBu)), 20.69, 20.58, 20.33
(CH3 (Ac)), 19.25 (C (tBu)) ppm. Anal. Calcd for
C55H68O17Si2: C 62.48, H 6.48. Found: C 62.27, H 6.56.
16: [a]2D0ZC60.2 (c 1.0, CHCl3). 1H NMR (CDCl3) d 8.14,
7.95 (2s, 2H, 2HC]O), 7.68 (m, 4H, Ph–Hortho), 7.40 (m,
6H, Ph–Hmeta,para), 5.95 (d, 1H, JZ7.5 Hz, H-30), 5.53 (d,
1H, JZ3.7 Hz, H-1), 5.47 (t, 1H, JZ7.6 Hz, H-40), 5.37 (t,
1H, JZ9.8 Hz, H-3), 4.97 (t, 1H, JZ9.8 Hz, H-4), 4.79 (dd,
t
(6s, 18H, 6OCH3), 1.04 (s, 9H, Bu–H) ppm. 13C NMR
(CDCl3) d 170.28, 170.03, 169.87, 169.70, 169.22
(H3CC]O), 160.44 (HC]O), 135.72, 135.66 (C–Hortho
(Ph)), 133.05, 132.93 (C (Ph)), 129.67 (C–Hpara (Ph)),
127.66 (C–Hmeta (Ph)), 104.080 (C-20), 90.64 (C-1), 78.70
(C-50), 75.82 (C-30), 74.92 (C-4 ), 70.78 (C-5), 70.55 (C-2),
70.08 (C-3), 68.11 (C-4), 62.76 (C-60), 62.25 (C-10), 61.60
(C-6), 26.72 (CH3 (tBu)), 20.64, 20.48 (CH3 (Ac)), 19.19 (C
(tBu)) ppm. Anal. Calcd for C41H52O18Si: C 57.20, H 6.09.
Found: C 57.44, H 6.26. 13: 1H NMR (CDCl3) d 8.15 (s, 1H,
HC]O), 7.69 (m, 4H, Ph–Hortho), 7.42 (m, 6H, Ph–
Hmeta,para), 5.95 (d, 1H, JZ7.3 Hz, H-30), 5.54 (d, 1H, JZ
3.6 Hz, H-1), 5.45 (t, 1H, JZ7.4 Hz, H-40), 5.37 (t, 1H, JZ
9.9 Hz, H-3), 5.02 (t, 1H, JZ9.7 Hz, H-4), 4.81 (dd, 1H,
J1,2Z3.7 Hz, J2,3Z10.3 Hz, H-2), 4.46 (dd, 1H, J5,6a
Z
3.2 Hz, J6a,6bZ12.1 Hz, H-6a), 4.35 (dd, 1H, J5,6bZ6 Hz,
J6a,6bZ12.1 Hz, H-6b), 4.23 (m, 2H, H-5,50), 4.12 (dd, 1H,
1H, J1,2Z3.7 Hz, J2,3Z10.3 Hz, H-2), 4.46 (dd, 1H, J5,6a
Z
J5 ,6 bZ4.1 Hz, J6 a,6 bZ14.4 Hz, H-60b), 4.05 (d, 1H,
3.3 Hz, J6a,6bZ12.1 Hz, H-6a), 4.36 (dd, 1H, J5,6bZ6 Hz,
0
0
0
0
J6 a,6 bZ11 Hz, H-60a), 3.76 (d, 1H, JZ10.8 Hz, H-10a),
3.50 (d, 1H, JZ10.8 Hz, H-10b), 2.16, 2.08, 2.05, 2.01, 1.97,
1.71 (6s, 18H, 6OCH3), 1.08 (s, 9H, tBu–H) ppm. 13C NMR
(CDCl3) d 170.08, 169.77, 169.94 (H3CC]O), 160.54
(HC]O), 135.57 (C–Hortho (Ph)), 132.58 (C (Ph)), 129.90
(C–Hpara (Ph)), 127.79 (C–Hmeta (Ph)), 104.93 (C-20), 89.62
(C-1), 77.98 (C-50), 74.99 (C-30), 74.50 (C-40), 69.93 (C-2),
69.81 (C-3), 68.20 (C-4,5), 64.14 (C-10), 62.86 (C-6), 61.74
(C-66), 26.65 (CH3 (tBu)), 20.73, 20.61, 20.21 (CH3 (Ac)),
19.20 (C (tBu)) ppm. m/z (CI) 318 (100%, C13H18O9).
Found: M, 318.0943 requires M, 318.0951. m/z (CI) 289
(23%, C28H36O8Si–C16H19Si). Found: 289.0972 requires
289.0923. 14: mp 117–118 8C. [a]2D0ZC71.6 (c 1.0,
J6a,6bZ12.1 Hz, H-6b), 4.26 (m, 3H, H-5,50,60a), 4.17 (dd,
0
0
1H, J5 ,6 bZ5.1 Hz, J6 a,6 bZ12.2 Hz, H-60b), 3.75 (d, 1H,
JZ10.9 Hz, H-10a), 3.49 (d, 1H, JZ10.8 Hz, H-10b), 2.15,
2.08, 2.02, 1.96, 1.69 (5s, 15H, 5OCH3), 1.07 (s, 19H,
tBu–H) ppm. 13C NMR (CDCl3) d 170.17, 170.04, 169.75,
169.53 (H3CC]O), 160.53 (HC]O), 135.60 (C–Hortho
(Ph)), 132.60 (C (Ph)), 129.96, 129.90 (C–Hpara (Ph)),
127.86, 127.79 (C–Hmeta (Ph)), 104.85 (C-20), 89.43 (C-1),
78.00 (C-50), 74.92 (C-30), 74.40 (C-40), 69.90 (C-2), 69.73
(C-3), 68.57 (C-4), 68.02 (C-5), 64.04 (C-10), 62.85 (C-6),
61.36 (C-60), 26.65 (CH3 (tBu)), 20.71, 20.59, 20.17 (CH3
(Ac)), 19.23 (C (tBu)) ppm. Anal. Calcd for C40H50O18Si: C
56.73, H 5.95. Found: C 56.49, H 5.95.
0
0
0
0

9242
M. M. Andrade, M. T. Barros / Tetrahedron 60 (2004) 9235–9243
3.3.5. 10,2,3,30,4,40-Hexa-O-acetyl-6-O-TBDMS-60-O-
formyl-sucrose (17), 10,2,3,30,4,40-hexa-O-acetyl-6-O-
formyl-60-O-TBDMS-sucrose (18). Prepared from 7.
Column chromatography with hexane/ethyl acetate 1:1
afforded 17 (110.5 mg, 15%, colourless oil), 18 (132.6 mg,
18%, colourless oil), 14 (240.7 mg, 37%, colourless
needles) and 7 recovered (139.9 mg, 17%). 17: [a]2D0Z
C77.6 (c 1, CHCl3). 1H NMR (CDCl3) d 8.14 (s, 1H,
HC]O), 5.63 (d, 1H, JZ3.4 Hz, H-1), 5.45 (d, 1H, JZ
5.6 Hz, H-300), 5.44 (t, 1H, JZ8.8 Hz, H-3), 5.39 (t, 1H, JZ
6.1 Hz, H-4 ), 5.15 (t, 1H, JZ9.8 Hz, H-4), 4.83 (dd, 1H,
2tBu–H), 0.07, 0.05, 0.02 (3s, 12H, 2Si–(CH3)2) ppm. 13C
NMR (CDCl3) d 170.43, 170.05, 169.67, 169.23
(H3CC]O), 160.60 (HC]O), 105.02 (C-20), 89.96 (C-1),
78.02 (C-50), 75.31 (C-30), 74.78 (C-40), 70.58 (C-5), 70.42
(C-2), 70.31 (C-3), 68.41 (C-4), 63.69 (C-10), 62.73 (C-60),
61.41 (C-6), 25.85, 25.73 (CH3 (tBu)), 20.70 (CH3 (Ac)),
18.19 (C (tBu)) ppm. Anal. Calcd for C35H60O17Si2: C
51.96, H 7.48. Found: C 52.23, H 7.42. 20: [a]2D0ZC75 (c
1.0, CHCl3). 1H NMR (CDCl3) d 8.08 (s, 1H, HC]O), 5.76
(d, 1H, JZ3.7 Hz, H-1), 5.65 (d, 1H, JZ6.7 Hz, H-30), 5.48
(t, 1H, JZ6.9 Hz, H-40), 5.45 (t, 1H, JZ10 Hz, H-3), 5.05
0
0
J1,2Z3.5 Hz, J2,3Z10.3 Hz, H-2), 4.45 (dd, 1H, J5 ,6 a
Z
Z
Z
(t, 1H, JZ9.8 Hz, H-4), 4.86 (dd, 1H, J1,2Z3.8 Hz, J2,3Z
4 Hz, J6 a,6 bZ11.9 Hz, H-60a), 4.35 (dd, 1H, J5 ,6 b
10.3 Hz, H-2), 4.38 (dt, 1H, J4,5Z10.3 Hz, J5,6Z3.3 Hz,
H-5), 4.30 (dd, 1H, J5,6bZ3.7 Hz, J6a,6bZ12.4 Hz, H-6b),
4.26 (dd, 1H, J5,6aZ2.8 Hz, J6a,6bZ11.7 Hz, H-6a), 4.15
0
0
0
0
6.3 Hz, J6 a,6 bZ11.9 Hz, H-60b), 4.24 (d,m, 2H, J1 a,1 b
0
0
0
0
11.9 Hz, H-10a,50), 4.14 (d, 1H, JZ12.2 Hz, H-10b), 4.07
(bd, 1H, J4,5Z9.9 Hz, H-5), 3.73 (d, 1H, J6a,6bZ10.5 Hz,
H-6a), 3.68 (dd, 1H, J5,6bZ3.5 Hz, J6a,6bZ11.5 Hz, H-6b),
2.14, 2.10, 2.01, 2.00 (4s, 18H, 6OCH3), 0.87 (s, 9H,
tBu–H), 0.02, 0.02 (2s, 6H, Si–(CH3)2) ppm. 13C NMR
(CDCl3) d 170.17 (H3CC]O), 160.46 (HC]O), 103.82
(C-20), 90.38 (C-1), 78.56 (C-50), 75.71 (C-30), 74.78 (C-40),
70.80 (C-5), 70.38 (C-2), 70.00 (C-3), 68.31 (C-4), 62.90
(C-60), 62.75 (C-10), 61.45 (C-6), 25.83 (CH3 (tBu)), 20.67,
20.59, 20.48 (CH3 (Ac)), 18.33 (C (tBu)) ppm. Anal. Calcd
for C31H48O18Si: C 50.53, H 6.57. Found: C 50.18, H 6.49.
18: [a]2D0ZC64 (c 1.0, CHCl3). 1H NMR (CDCl3) d 8.08 (s,
1H, HC]O), 5.74 (d, 1H, JZ3.7 Hz, H-1), 5.47 (t, 1H, JZ
6.1 Hz, H-400), 5.42 (t, 1H, JZ9.8 Hz, H-3), 5.42 (d, 1H, JZ
6.1 Hz, H-3 ), 5.06 (t, 1H, JZ9.8 Hz, H-4), 4.85 (dd, 1H,
(q, 1H, JZ4.9 Hz, H-50), 3.83 (dd, 1H, J5 ,6 aZ4.3 Hz,
0
0
J6 a,6 bZ10.8 Hz, H-60a), 3.78 (dd, 1H, J5 ,6 bZ4.9 Hz,
0
0
0
0
J6 a,6 bZ10.7 Hz, H-60b), 3.73 (d, 1H, JZ11 Hz, H-10a),
3.47 (d, 1H, JZ11 Hz, H-10b), 2.10, 2.05, 2.03, 2.01 (4s,
15H, 5OCH3), 0.90, 0.89 (2s, 18H, 2tBu–H), 0.07, 0.06, 0.03
(3s, 12H, 2Si–(CH3)2) ppm. 13C NMR (CDCl3) d 170.11,
169.99, 169.81, 169.62 (H3CC]O), 160.55 (HC]O),
104.73 (C-20), 89.07 (C-1), 80.99 (C-50), 75.35 (C-30),
74.70 (C-40), 70.08 (C-2), 69.93 (C-3), 68.58 (C-4), 67.78
(C-5), 63.66 (C-10), 63.19 (C-60), 61.32 (C-6), 25.74 (CH3
(tBu)), 20.65 (CH3 (Ac)), 18.21 (C (tBu)) ppm. Anal. Calcd
for C35H60O17Si2: C 51.96, H 7.48. Found: C 52.02, H 7.58.
21: [a]2D0ZC69.4 (c 1.0, CHCl3). 1H NMR (CDCl3) d 8.12,
8.07 (2s, 2H, 2HC]O), 5.66 (d, 1H, JZ6.8 Hz, H-30), 5.62
(d, 1H, JZ3.6 Hz, H-1), 5.44 (t, 1H, JZ9.8 Hz, H-3), 5.39
(t, 1H, JZ6.9 Hz, H-40), 5.02 (t, 1H, JZ9.8 Hz, H-4), 4.84
(dd, 1H, J1,2Z3.7 Hz, J2,3Z10.4 Hz, H-2), 4.43 (dd, 1H,
0
0
J1,2Z3.7 Hz, J2,3Z10.4 Hz, H-2), 4.33 (dt, 1H, J4,5
Z
10.2 Hz, J5,6Z3.5 Hz, H-5), 4.27 (ds, 2H, H-6), 4.18 (d, 1H,
JZ12.2 Hz, H-10a), 4.14 (d, 1H, JZ12.3 Hz, H-10b), 4.05
(q, 1H, JZ5.5 Hz, H-50), 3.86 (dd, 1H, J5 ,6 aZ1.8 Hz,
J5 ,6 aZ3.4 Hz, J6 a,6 bZ12.1 Hz, H-60a), 4.32 (dd, 1H,
0
0
0
0
0
0
J6 a,6 bZ10.9 Hz, H-60a), 3.80 (dd, 1H, J5 ,6 bZ2.1 Hz,
J5 ,6 bZ5.9 Hz, J6 a,6 bZ12 Hz, H-60b), 4.29 (m, 1H, H-5),
4.26 (m, 1H, H-6a), 4.22 (dd, 1H, J5,6bZ5 Hz, J6a,6b
0
0
0
0
0
0
0
0
J6 a,6 bZ11.1 Hz, H-60b), 2.14, 2.10, 2.09, 2.07, 2.04, 2.01
(6s, 18H, 6OCH3), 0.89 (s, 9H, tBu–H), 0.08, 0.07 (2s, 6H, Si–
(CH3)2) ppm. 13C NMR (CDCl3) d 170.03 (H3CC]O), 160.53
(HC]O), 103.58 0(C-20), 89.52 (C-1), 81.42 (C-50), 76.14
(C-30), 74.86 (C-4 ), 70.19 (C-2), 69.64 (C-3), 68.49 (C-4),
68.10 (C-5), 63.28 (C-60), 63.05 (C-10), 61.23 (C-6), 25.79 (CH3
(tBu)), 20.60 (CH3 (Ac)), 18.30 (C (tBu)) ppm. Anal. Calcd for
C31H48O18Si: C 50.53, H 6.57. Found: C 50.32, H 6.53.
Z
0
0
12.3 Hz, H-6b), 4.15 (dt, 1H, JZ6.4, 3.7 Hz, H-50), 3.760(d,
1H, JZ10.9 Hz, H-10a), 3.51 (d, 1H, JZ10.9 Hz, H-1 b),
2.12, 2.06, 2.04, 2.03, 2.00 (5s, 15H, 5OCH3), 0.89 (s, 9H,
tBu–H), 0.07, 0.05 (2s, 6H, Si–(CH3)2) ppm. 13C NMR
(CDCl3) d 170.09, 169.87, 169.56 (H3CC]O), 160.52
(HC]O), 104.99 0(C-20), 89.70 (C-1), 78.26 (C-50), 75.17
(C-30), 74.65 (C-4 ), 70.017 (C-2), 69.65 (C-3), 68.54 (C-4),
68.00 (C-5), 63.58 (C-1 ), 62.72 (C-60), 61.37 (C-6), 25.69
(CH3 (tBu)), 20.57 (CH3 (Ac)), 18.18 (C (tBu)) ppm. Anal.
Calcd for C30H46O18Si: C 49.85, H 6.42. Found: C 49.77, H
3.3.6. 10,6-Di-O-TBDMS-2,3,30,4,40-penta-O-acetyl-60-O-
formyl-sucrose (19), 10,60-di-O-TBDMS-2,3,30,4,40-
penta-O-acetyl-6-O-formyl-sucrose (20), 10-O-TBDMS-
2,3,30,4,40-penta-O-acetyl-6,60-di-O-formyl-sucrose (21)
and 10,6,60-tri-O-formyl-2,3,30,4,40-penta-O-acetyl-sucrose
(22). Prepared from 8. Column chromatography with hexane/
ethyl acetate 1:1 afforded 19 (80.9 mg, 10%, colourless oil),
20 (105.2 mg, 13%, colourless oil), 21 (224.1 mg, 31%), 22
(31.8 mg, 5%, colourless oil) and 8 recovered (286.5 mg,
32%). 19: [a]2D0ZC60.8 (c 1.0, CHCl3). 1H NMR (CDCl3)
d 8.13 (s, 1H, HC]O), 5.56 (d, 1H, JZ6.8 Hz, H-30), 5.61
(d, 1H, JZ3.6 Hz, H-1), 5.43 (t, 1H, JZ9.4 Hz, H-3), 5.39
(t, 1H, JZ6.8 Hz, H-40), 5.17 (t, 1H, JZ9.7 Hz, H-4), 4.81
(dd, 1H, J1,2Z3.6 Hz, J2,3Z10.4 Hz, H-2), 4.41 (d, 1H,
1
6.45. 22: [a]2D0ZC62 (c 1.0, CHCl3). H NMR (CDCl3) d
8.13, 8.12, 8.09 (3s, 3H, 2HC]O), 5.65 (d, 1H, JZ3.3 Hz,
H-1), 5.53 (d, 1H, JZ7.1 Hz, H-30), 5.46 (2t, 2H, J3Z
0
0
9.5 Hz, J4 Z7.4 Hz, H-3,4 ), 5.04 (t, 1H, JZ9.8 Hz, H-4),
4.91 (dd, 1H, J1,2Z3.5 Hz, J2,3Z10.4 Hz, H-2), 4.44 (dd,
1H, J5 ,6 aZ3.2 Hz, J6 a,6 bZ12 Hz, H-60a), 4.40 (dd, 1H,
0
0
0
0
J5 ,6 bZ6.4 Hz, J6 a,6 bZ12.1 Hz, H-60b), 4.29 (m, 1H, H-5),
4.30 (m, 5H, H-5,10a,6a,6b,50), 4.20 (d, 1H, JZ12.1 Hz,
H-10b), 2.18, 2.11, 2.06, 2.02 (4s, 15H, 5OCH3) ppm. 13C
NMR (CDCl3) d 169.98, 169.80, 169.49 (H3CC]O),
160.50, 160.40, 159.67 (HC]O), 103.030 (C-20), 89.82
(C-1), 78.40 (C-50), 75.49 (C-30), 74.006 (C-4 ), 69.98 (C-2),
69.44 (C-3), 68.43 (C-4,5), 62.81 (C-6 ), 62.54 (C-10), 61.36
(C-6), 20.53, 20.46 (CH3 (Ac)) ppm. Anal. Calcd for
C25H32O19: C 47.17, H 5.07. Found: C 46.99, H 5.07.
0
0
0
0
J6 a,6 bZ11.8 Hz, H-60a), 4.30 (dd, 1H, J5 ,6 bZ5.2 Hz,
0
0
0
0
J6 a,6 bZ12 Hz, H-60b), 4.15 (bs, 1H, H-50), 4.08 (bd, 1H,
0
0
J4,5Z10.3 Hz, H-5), 3.77 (d, 1H, JZ11.2 Hz, H-10a), 3.74
(m, 1H, H-6a), 3.68 (dd, 1H, J5,6bZ1.1 Hz, J6a,6b
Z
11.6 Hz, H-6b), 3.53 (d, 1H, JZ10.8 Hz, H-10b), 2.10,
2.06, 2.04, 2.00 (4s, 15H, 5OCH3), 0.89, 0.87 (2s, 18H,
3.3.7. 10-O-Formyl-2,3,30,4,40-penta-O-acetyl-6,60-di-O-
TBDPS-sucrose (23) and 10,60-di-O-formyl-2,3,30,4,

M. M. Andrade, M. T. Barros / Tetrahedron 60 (2004) 9235–9243
9243
40-penta-O-acetyl-6-O-TBDPS-sucrose (24). Prepared
from 9. Column chromatography with hexane/ethyl acetate
2:1 afforded 23 (729.5 mg, 69%, colourless needles) and 24
(177.8 mg, 21%, colourless oil). 23: mp 105–106 8C.
Tecnologia for financial support (PRAXIS SFRH/BD/878/
2000 and POCTI/QUI/47973/2002).
[a]2D0ZC54 (c 1.0, CHCl3). H NMR (CDCl3) d 8.05 (s,
1
1H, HC]O), 7.62 (m, 8H, Ph–Hortho), 7.34 (m, 12H, Ph–
Hmeta,para), 5.61 (d, 1H, JZ3.6 Hz, H-1), 5.45 (t, 1H, JZ
5.3 Hz, H-400), 5.39 (t, 1H, JZ9.6 Hz, H-3), 5.36 (d, 1H, JZ
5.3 Hz, H-3 ), 5.34 (t, 1H, JZ9.5 Hz, H-4), 4.86 (dd, 1H,
J1,2Z3.6 Hz, J2,3Z9.8 Hz, H-2), 4.30 (s, 2H, H-1), 4.08 (q,
1H, JZ5.8 Hz, H-50), 3.99 (bd, 2H, JZ9.4 Hz, H-5), 3.83
References and notes
1. Davis, B. G.; Fairbanks, A. J.;. 1st ed. Carbohydrate
Chemistry, Vol. 99; Oxford University Press: New York, 2002.
2. Jarosz, S.; Mach, M.; Eur J. Org. Chem. 2002, 769–780.
3. Franke, F.; Guthrie, R. D. Aust. J. Chem. 1977, 30, 639–647.
4. Haworth, W. N.; Gregory, H.; Wiggins, L. F. J. Chem. Soc.
1946, 488.
(dd, 1H, J5,6 aZ5.7 Hz, J6 a,6 bZ10.8 Hz, H-60a), 3.77 (dd,
0
0
0
1H, J5,6 bZ6.5 Hz, J6 a,6 bZ10.8 Hz, H-60b), 3.62 (d, 1H,
J6a,6bZ10.5 Hz, H-6a), 3.53 (dd, 1H, J5,6bZ2.7 Hz,
J6a,6bZ11.7 Hz, H-6b), 2.11, 2.06, 2.03, 2.01, 1.87 (5s,
15H, 5OCH3), 1.02 (s, 18H, 2tBu–H) ppm. 13C NMR
(CDCl3) d 170.27, 169.82, 169.65, 169.21 (H3CC]O),
159.90 (HC]O), 135.69, 135.54 (C–Hortho (Ph)), 133.11,
132.92 (C (Ph)), 129.79 (C–Hpara (Ph)), 127.76 (C–Hmeta
(Ph)), 103.90 (C-20), 90.52 (C-1), 81.50 (C-50), 76.56 (C-30),
75.74 (C-40), 70.65 (C-5), 70.41 (C-2), 70.30 (C-3), 68.04
(C-4), 64.08 (C-60), 62.15 (C-10), 61.36 (C-6), 26.74 (CH3
(tBu)), 20.79, 20.69, 20.57 (CH3 (Ac)), 19.19 (C (tBu)) ppm.
Anal. Calcd for C55H68O17Si2: C 62.48, H 6.48. Found: C
0
0
0
5. Barros, M. T.; Sin˜eriz, F. Synthesis 2002, 10, 1407–1411.
6. Sachinvala, N. D.; Niemczura, W. P.; Litt, M. H. Carbohydr.
Res. 1991, 218, 237–245.
7. Carneiro, M. J.; Fernandes, A.; Figueiredo, C. M.; Fortes,
A. G.; Freitas, A. M. Carbohydr. Polym. 2001, 45, 135–138.
8. Narain, R.; Jhurry, D.; Wulff, G. Eur. Polym. J. 2002, 38,
273–280.
´
9. Jarosz, S.; Szewczyk, K.; Skora, S.; Ciunik, Z.; Pietrzak, A.
Tetrahedron: Asymmetry 2002, 13, 2223–2228.
10. Giuliano, R. M.; Alfonzo, D.; Jordan, J.; Gauthier, A. D.;
Hoogsteen, K. J. Org. Chem. 1993, 58, 4979–4988.
11. Ferreira, M. L. G.; Pinheiro, S.; Perrone, C. C.; Costa,
P. R. R.; Ferreira, V. F. Tetrahedron: Asymmetry 1998, 9,
2671–2680.
62.67, H 6.59. 24: [a]2D0ZC75.4 (c 1.0, CHCl3). H NMR
1
(CDCl3) d 8.06, 8.05 (2s, 2H, 2HC]O), 7.65 (m, 4H, Ph–
Hortho), 7.40 (m, 6H, Ph–Hmeta,para), 5.65 (d, 1H, JZ3.6 Hz,
H-1), 5.47 (t, 1H, JZ9.9 Hz, H-3), 5.46 (d, 1H, JZ6.5 Hz,
H-300), 5.37 (t, 1H, JZ9.6 Hz, H-4), 5.37 (t, 1H, JZ6.6 Hz,
H-4 ), 4.91 (dd, 1H, J1,2Z3.6 Hz, J2,3Z10.3 Hz, H-2), 4.39
12. Beagley, B.; Curtis, A. D. M.; Prithard, R. G.; Stoodley, R. J.
J. Chem. Soc., Perkin Trans. 1 1992, 1981–1991.
13. Strazzolini, P.; Giumanini, A. G.; Cauci, S. Tetrahedron 1990,
46, 1081–1118.
(dd, 1H, J5 ,6 aZ3.5 Hz, J6 a,6 bZ11.9 Hz, H-60a), 4.34 (d,
0
0
0
0
1H, JZ12.1 Hz, H-10a), 4.27 (dd, 1H, J5 ,6 bZ6.1 Hz,
0
0
J6 a,6 bZ11.9 Hz, H-60b), 4.22 (d, 1H, JZ11.5 Hz, H-10b),
4.22 (m, 1H, H-50), 4.10 (bd, 1H, JZ10 Hz, H-5), 3.76 (dd,
1H, J5,6aZ1.6 Hz, J6a,6bZ11.7 Hz, H-6a), 3.69 (dd, 1H,
J5,6bZ3.1 Hz, J6a,6bZ11.8 Hz, H-6b), 2.12, 2.10, 2.07,
0
0
14. Katritzky, A. R.; Chang, H.-X.; Yang, B. Synthesis 1995,
503–505.
15. Barluenga, J.; Campos, P. J.; Gonzales-Nun˜ez, E.; Asensio, G.
Synthesis 1985, 426–428.
t
2.03, 1.93 (5s, 15H, 5OCH3), 1.05 (s, 9H, Bu–H) ppm.
13C NMR (CDCl3) d 170.36, 170.24, 169.84, 169.21
(H3CC]O), 160.45, 159.72 (HC]O), 135.70 (C–Hortho
(Ph)), 132.99 (C (Ph)), 129.73 (C–Hpara (Ph)), 127.68
(C–Hmeta (Ph)), 103.45 (C-20), 90.57 (C-1), 78.45 (C-50),
75.74 (C-30), 74.40 (C-40), 70.84 (C-5), 70.37 (C-2), 70.07
(C-3), 68.06 (C-4), 62.64 (C-60), 62.25 (C-10), 61.59 (C-6),
26.73 (CH3 (tBu)), 20.66 (CH3 (Ac)), 19.18 (C (tBu)) ppm.
Anal. Calcd for C40H50O18Si: C 56.73, H 5.95. Found: C
56.35, H 5.94.
16. Olah, G. A.; Ohannesian, L.; Arvanaghi, M. Chem. Rev. 1987,
87, 671–686.
17. Hagiwara, H.; Morohashi, K.; Sakai, H.; Suzuki, T.; Ando, M.
Tetrahedron 1998, 54, 5845–5852.
18. Koeller, S.; Lellouche, J.-P. Tetrahedron Lett. 1999, 40,
7043–7046.
19. Lellouche, J.-P.; Koeller, S. J. Org. Chem. 2001, 66, 693–696.
20. Lellouche, J.-P.; Kotlyar, V. Synlett 2004, 3, 564–571.
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The authors are grateful to Fundac¸a˜o para a Ciencia e a