Peracetylated β-allyl C-glycosides of D-ribofuranose and 2-deoxy-D-ribofuranose in the chemical literature: Until now, mirages in the literature

Article abstract of DOI:10.1055/s-0029-1216794

The peracetylated β-allyl C-glycosides of D-ribofuranose (8) and 2-deoxy-D-ribofuranose (13) were stereoselectively prepared via the isopropylidene derivatives 3 and 4. These reactions represent what are, to the best of our knowledge, the first preparation of these apparently simple derivatives whose structures were carefully proved by NMR and X-ray investigations. Publications which allegedly described the synthesis of 8 and 13 were critically examined. Georg Thieme Verlag Stuttgart.

Full text of DOI:10.1055/s-0029-1216794

1834
PAPER
Peracetylated b-Allyl C-Glycosides of D-Ribofuranose and 2-Deoxy-D-ribo-
furanose in the Chemical Literature: Until Now, Mirages in the Literature
P
eracetylate
d
b
-Al
e
lyl C-Glyco
i
sides ke Otero Martinez,a,1 Helmut Reinke,a Dirk Michalik,b Christian Vogel*a
a
Institute of Chemistry, University of Rostock, Albert-Einstein-Str. 3a, 18059 Rostock, Germany
Fax +49(381)4986412; E-mail: christian.vogel@uni-rostock.de
b
Leibniz Institute for Catalysis, University of Rostock, Albert-Einstein-Str. 29a, 18059 Rostock, Germany
Received 27 January 2009; revised 25 March 2009
Dedicated to Professor Dr. Klaus Peseke on the occasion of his 70th birthday
AcO
OAc
AcO
Abstract: The peracetylated b-allyl C-glycosides of D-ribofuranose
O
O
i
(8) and 2-deoxy-D-ribofuranose (13) were stereoselectively pre-
pared via the isopropylidene derivatives 3 and 4. These reactions
represent what are, to the best of our knowledge, the first prepara-
tion of these apparently simple derivatives whose structures were
carefully proved by NMR and X-ray investigations. Publications
which allegedly described the synthesis of 8 and 13 were critically
AcO
OAc
AcO
OAc
I
II
ii
examined.
N3
HO
O
O
Key words: allylation, glycosylation, C-glycosides, nucleosides,
iii
stereoselectivity
AcO
OAc
HO
OH
VI
III
The preparation of novel nucleoside analogues as antiviral
and antitumor agents is critical for drug development. In
addition to the modification of the sugar residue of nucle-
osides, there is an increasing interest in compounds with a
tetrahydrofuran ring and C-linked substituents at the ano-
meric center, the C-nucleosides. Due to the replacement
of the N-glycosidic bond, these compounds possess great-
er stability towards enzyme catalyzed metabolism. Homo-
nucleosides are a variation of C-nucleosides in which a
methylene or alkylidene group is inserted between C-1 of
the tetrahydrofuran ring and the heterocycle.2,3 b-C-Allyl
glycosides of D-ribofuranose and 2-deoxy-D-ribofuranose
are convenient precursors for the synthesis of homonucle-
osides, and so there is interest to prepare these compounds
stereoselectively and on gram-scale.
Scheme 1 Alleged synthesis of compound II and consecutive reac-
tions. Reagents and conditions: (i) AllTMS, TMSOTf, MeCN;
(ii) LiOMe, MeOH; (iii) TsCl, py, then NaN3, DMF, finally Ac2O,
Et3N, DMAP, CH2Cl2.
ment with allyltrimethylsilane (AllTMS) and zinc bro-
mide in MeNO2 as solvent.9 While Fürstner et al. who
used instead trimethylsilyl triflate ((TMSOTf) as promot-
er and MeCN as solvent obtained the a/b-epimers in 63%
overall yield (a/b ratio of 1:10)10 we were able to isolate
the pure b-C-allyl glycoside 5 in 78% yield from the reac-
tion mixture (a/b ratio 1:7).
The employment of a bulkier protecting group at the O-5
position, in our example a TBDPS group, resulted in a de-
crease in both in yield and stereoselectivity. Although
Wilcox and Otoski obtained the corresponding C-allyl
A supposedly simple procedure for synthesis of the per-
acetylated b-C-allyl glycosides of D-ribofuranose has
been described by McDevitt and Lansbury, Jr. as shown in
Scheme 1.4 To confirm the structures I and II we carried
out the complementary experiments as shown in
Scheme 2.
glycosides bearing
a tert-butyldimethylsilyl group
(TBDMS) in 84% overall yield and in an a/b ratio of
1:16,9 we obtained a reaction mixture with an a/b ratio of
1:3 from which nearly pure b-C-allyl glycoside 6 was iso-
lated in 55% yield. X-ray diffraction studies of compound
6 (Figure 1) established its structure and confirmed the
tetrahydrofuran ring as well as the b-linkage to the allyl
residue with C-1¢ possessing S-configuration.
In order to fix the furanose form, D-ribose was condensed
with acetone to provide 2,3-O-isopropylidene-D-ribose
(2),5–7 which was transformed into the diacetyl derivative
36 in 94% yield. Selective protection of the primary hy-
droxyl group of 2 with a tert-butyldiphenylsilyl group
(TBDPS) followed by acetylation provided compound 48
in 75% overall yield from 2. 1-O-Acetates 3 and 4 were
both converted into the C-allyl glycosides 5 and 6 by treat-
At present, the best pathway to synthesize a b-allyl C-gly-
coside of D-ribofuranose proceeds via the 2,3-O-isopropy-
lidene diacetate 3.
Next, complete deprotection of C-glycoside 5 was
achieved by treatment with hydrogen chloride in ethanol–
water for 2 days at room temperature in 80% yield
(Scheme 3). In a similar fashion, compound 6 was depro-
tected using a two-step procedure in which the TBDPS
group was cleaved off by tetrabutylammonium fluoride
(TBAF) followed by removal of the isopropylidene group
SYNTHESIS 2009, No. 11, pp 1834–1840
x
x.
x
x
.
2
0
0
9
Advanced online publication: 12.05.2009
DOI: 10.1055/s-0029-1216794; Art ID: T01909SS
© Georg Thieme Verlag Stuttgart · New York

PAPER
Peracetylated b-Allyl C-Glycosides
1835
HO
HO
O
O
i
O
OH
OH
HO
Si
O
O
O
iii
95%
i
OH OH
5,6
O
O
~78%
68%
Si
1f
O
OH
OH OH
2
9
7
ii
iv
ii 79%
O
HO
O
R
RO
OAc
Si
O
OH
OH
O
OH
O
AcO
O
1p
Si
O
O
O
10: R = I (95%)
11: R = H (70%)
iii
AcO
OAc
8
3: R = Ac (94%)
RO
4: R = TBDPS (75%)
O
v
98%
O
O
HO
AcO
O
O
ii
83%
OH
AcO
5: R = Ac (78%)
13
12
6: R = TBDPS (55%)
Scheme 2 Efficient synthesis of a b-allyl C-glycoside of D-ribofura-
nose 5. Reagents and conditions: (i) H2SO4 (cat.), acetone; (ii) Ac2O,
py (3) or TBDPSCl, DMF, imidazole, followed by Ac2O, py (4);
(iii) AllTMS, ZnBr2, MeNO2.
Scheme 3 Synthesis of the title compounds 8 and 13. Reagents and
conditions: (i) aq HCl, EtOH (for 5); TBAF, 1,4-dioxane, then aq
HCl, EtOH (for 6); (ii) Ac2O, py; (iii) TIPDSCl, py; (iv) I2, Ph3P, imi-
dazole, toluene (10), then Bu3SnH, AIBN, toluene (11); (v) TBAF,
1,4-dioxane.
H
5'
H
1'
AcO
H
2
O
1'
H
OAc
4'
H
AcO
H
4'
O
1
3
H
H
3'
2'
OAc
AcO
OAc
16
8
H
H
H
4'
5'
O
1
3
2'
AcO
H
1'
3'
2
H
H
AcO
H
19
Figure 2 Relevant NOE correlations of compounds 8, 16, and 19
tons H-1¢ and H-4¢. On the other hand, no NOE was ob-
served between the protons H-1¢ and H-5¢ (Figure 2).
In order to synthesize the corresponding 2-deoxy deriva-
tive, the unprotected compound 7 was treated with 1,3-
dichloro-1,1,3,3-tetraisopropyldisiloxane (TIPDSCl) in
pyridine (Scheme 3). The TIPDS-protected derivative 9
was thus obtained in 68% yield. The first strategy em-
ployed for the free radical deoxygenation of compound 9
was based on a method originally developed by Barton
and McCombie.11 The coupling reaction between com-
pound 9 and phenyl chlorothionocarbonate12 or 1,1¢-
thiocarbonyldiimidazole13 yielded the corresponding
thiocarbonyl derivatives in 80% and 90%, respectively.
Figure 1 ORTEP plot of compound 6 with S-configured C1A;
puckering parameters are Q = 0.2993(10) Å, F = 56.39(19)°
with dilute acid. Simple acetylation of 7 with acetic anhy-
dride in pyridine furnished pure triacetate 8 in 80% yield.
The furanose structure of compound 8 was confirmed by
NMR measurements. Thus, in a two-dimensional NOESY
NMR spectrum a correlation was found between the pro-
Synthesis 2009, No. 11, 1834–1840 © Thieme Stuttgart · New York

1836
H. Otero Martinez et al.
PAPER
Unfortunately, the subsequent reduction with Bu3SnH or
hypophosphorous acid did not provide compound 11. On
the contrary, the starting material was quantitatively re-
covered. Alternatively, iodination procedure developed
by Garegg and Samuelsson14 gave the 2-iodo-2-deoxy-
arabino derivative 10 in 95% yield. Now, radical-based
reduction of 10 with Bu3SnH15 furnished the desired de-
rivative 11 in 70% yield. However, only a cautious re-
moval of Ph3P and its oxide led to the successful
formation of 11. Finally, treatment of 11 with TBAF fol-
lowed by classical acetylation of the unprotected deriva-
tive 12 led to the diacetate 13 in 83% overall yield.
AcO
O
O
AcO
OAc
+
R
OAc
AcO
R
AcO
14f: R = OAc
15f: R = H
14p: R = OAc
15p: R = H
i
iii
25%
O
O
AcO
OR
OR
AcO
19
RO
16: R = Ac (45%)
17: R = H (98%)
Both acetylated b-C-allyl D-ribofuranosyl derivatives 8
and 13 in hands, we compared our analytical data with
those of McDevitt and Lansbury, Jr.4 as well as Diederich-
sen and Biro.16 The first group described the reaction of
1,2,3,5-tetra-O-acetyl-b-D-ribofuranose (Scheme 1, com-
pound I) with AllTMS in the presence of TMSOTf as pro-
moter in MeCN as the solvent. Apparently, they obtained
an a/b mixture of the corresponding C-allyl ribofuranose
derivatives in a ratio of 1:3 in cumulative 87% yield. The
supposed b-derivative was purified and characterized by
1H NMR spectroscopy. Unfortunately, there is no refer-
ence to the origin of the peracetylated ribofuranose I not
even in the supplementary material. Obviously, the au-
thors ignored the fact that acetylation of free D-ribose to
get the peracetylated furanose derivatives I is not a simple
task. In 1953 two procedures have been published by
Zinner to synthesize either the pyranose or the furanose of
peracetylated ribose.17 The acetylation procedure at low
temperature (0 °C) provided compound 14p in 80% yield
predominantly as b-isomer, at higher temperature
(136 °C) the furanose derivative 14f was isolated in 43%
yield; both by crystallization (Scheme 4). Presumably,
McDevitt and Lansbury, Jr. used a furanose-pyranose
mixture of peracetylated D-ribose, which led to the ob-
served 1:3 mixture of products, that is, C-allyl ribofura-
nose and C-allyl ribopyranose. The real problem is that
the authors continued their work with the major product,
which was the ribopyranose. That explains why they got
only moderate or poor yields during the following steps
including tosylation and exchange of the tosyl group by
azide at a not existing primary hydroxyl group
(Scheme 1). Additionally, they did not obtain the b-iso-
mer, but they got the a-isomer 16 (Scheme 4). It is known
from the literature that steric hindrance of the isopropy-
lidene group favors the trans-1¢,2¢ isomer since peracety-
lated sugar derivatives show a general increase in the ratio
of cis-1¢,2¢ isomers.10,18
ii
O
77%
O
OH
18
O
Si
Si
O
Scheme 4 Synthesis of allyl C-glycosides of D-ribopyranose and
2-deoxy-D-ribopyranose with the object of comparison. Reagents and
conditions: (i) AllTMS, TMSOTf, MeCN (16), then NaOMe, MeOH
(17); (ii) TIPDSCl, py; (iii) AllTMS, TMSOTf, MeCN.
pound 8 and 16 with [a]D23 –0.7 and [a]D23 +18.6, respec-
tively. But, the determination of optical rotation in the
case of chiral compounds seems to become an old-fash-
ioned method since there are no data in the literature.4 Fur-
1
thermore, in the H NMR spectra of 8 the signal of H-1¢
appeared d = 4.01 while for 16 the signal of H-1¢ was
downfield shifted to d = 3.53. On the contrary, in 13C
NMR spectra of 8 the signals of C-2¢–C-4¢ (d = 71.5–
79.0) appeared at lower field than the same signals of
compound 16 (d = 66.7–68.3).
By detailed NMR investigation, based on coupling con-
stants and NOE’s, the conformation of compound 16
could be established as an a-configured 1C4-tetrahydropy-
ran ring. Thus, in a NOESY spectrum of 16, NOE corre-
lations were observed for the proton H-1¢ with H-2¢, H-3¢
and H-5¢-axial as well as for H-5¢-axial with H-1¢, H-3¢,
and H-4¢ (Figure 2). Furthermore, due to the small cou-
pling constants found for the ring protons (3J < 3.8 Hz)
any other structure with bis-axial positions of the ring pro-
tons can be excluded.
Fortunately, deacetylation of 16 to compound 17 followed
by introduction of the TIPDS group at O-3 and O-4 posi-
tion gave the crystalline derivative 18. In the NOESY
spectra recorded for 18 the same correlations as for com-
pound 16 were found and the coupling constants of 18
correspond to those of 16 and 17 proving also the a-con-
figured 1C4-tetrahydropyran structure. Besides NMR
studies, the structure of the compound 18 could be addi-
tionally proven by X-ray structure analysis (Figure 3).
The solid crystallizes in the orthorhombic space group
P212121 with two conformers per asymmetric unit. The
main difference between both structures lies in the confor-
We repeated the C-allylation with a furanose/pyranose
mixture of peracetylated D-ribose obtained by acetylation
at room temperature and got exactly the same ratio of
compounds as described by McDevitt and Lansbury, Jr.4
Isolation of the major product gave the a-isomer 16 in
45% yield (Scheme 4). The 1H NMR data of 16 are in ex-
cellent accordance with data published for the supposed
b-C-allyl ribofuranose. Comparing the values of optical
rotation, there are significant differences between com-
Synthesis 2009, No. 11, 1834–1840 © Thieme Stuttgart · New York

PAPER
Peracetylated b-Allyl C-Glycosides
1837
4
mation of the C-allyl group (see also the puckering para- a b-configured C1-tetrahydropyran ring structure. The
3
meters below). But even for conformer 1 there are hints vicinal coupling constants J1¢,2¢ax = 11.4 Hz and
from the refinement calculations for a disorder in the allyl 3J4¢,5¢ax = 10.7 Hz prove a bis-axial arrangement of these
group. All the other analytical data were also in good protons. Further, a long-range coupling between the pro-
agreement with the proposed structure of 18.
tons H-3¢ and H-5¢eq (4J = 1.2 Hz) has been found indicat-
ing a bis-equatorial position of these protons (W-
coupling). Furthermore, a NOESY spectrum of 19
showed correlations between the protons H-1¢ and H-5¢-
axial, as well as H-2¢-axial and H-4¢, which prove the b-
4C1 conformation (Figure 2).
In summary, this paper describes the first safe route for
the synthesis of peracetylated b-allyl C-glycosides of D-ri-
bofuranose (8) and 2-deoxy-D-ribofuranose (13). In addi-
tion, our reinvestigation of the synthetic pathways for
compound 8 and 13 published by McDevitt and Lansbury,
Jr.4 and by Diederichsen and Biro,16 respectively, has
shown that both pathways given therein lead mainly to de-
rivatives with six-membered rings instead of five-mem-
bered rings (compounds 16, 17, and 19). Presumably, the
reason for this mistake was the use of a mixture of per-
acetylated ribo- and deoxy-ribofuranose and -pyranose,
respectively, as starting material and the selection of the
wrong compounds from the reaction mixture for further
investigation.
Figure 3 ORTEP plot of compound 18 (conformer 2: 30% probabi-
lity for the displacement ellipsoids, hydrogens of methyl groups omit-
ted for clarity); puckering parameters of conformer 1 are Q = 0.587(5)
Å, Q = 175.8(6)°, F = 268(6)°, and of conformer 2 are Q = 0.577(6)
Å, Q = 177.8(7)°, F = 246(12)°
Melting points were determined with a Boetius micro-heating plate
BHMK 05 (Rapido, Dresden) and are not corrected. Optical rota-
tions were measured for solutions in a 2-cm cell with an automatic
polarimeter GYROMAT (Dr. Kernchen Co.). 1H NMR spectra
(250.13 MHz, 300.13 MHz, and 500.13 MHz) and 13C NMR spec-
tra (62.9 MHz, 75.5 MHz and 125.8 MHz) were recorded on Bruker
instruments AV 250, AV 300, and AV 500, respectively, with
The work of McDevitt and Lansbury, Jr.4 has to be revised
because other research groups used their procedure. Thus,
Roy and co-workers investigated the stereoselective
isomerization of C-allyl glycosides into C-vinyl glyco-
sides or exo-glycals using, among other things, the alleged
b-C-allyl ribofuranose prepared according to the pub- CDCl3 or DMSO-d6 as solvents. The calibration of spectra was car-
lished procedure.19 Moreover, Diederichsen and Biro
ried out on solvent signals (CDCl3: dH = 7.25, dC = 77.0; DMSO-d6:
1
dH = 2.50, dC = 39.7). H and 13C NMR signals were assigned by
transferred the false synthetic course to peracetylated 2-
1
1
DEPT, two-dimensional H–1H COSY and NOESY and H–13C
correlation spectra (HMBC and HSQC). For NMR numbering of
atoms, see Figure 2. Mass spectra were recorded on an AMD 402/3
spectrometer (AMD Intectra GmbH). Elemental analysis was per-
formed on a CHNS-Flash-EA-1112 instrument (Thermoquest). For
the X-ray structure determination of compounds 6 and 18 an
X8Apex system with CCD area detector was used (l = 0.71073 Å,
graphite monochromator). The structures were solved by direct
methods (Bruker-SHELXTL). The refinement calculations were
done by the full-matrix least-squares method of Bruker SHELXTL,
deoxy-D-ribose.16 They ignored the fact that acetylation of
free 2-deoxy-D-ribose always led to a complex mixture
from which the isolation of the desired furanose derivative
is time-consuming and cumbersome.20
We repeated the C-allylation under the same conditions as
described by Diederichsen and Biro16 and isolated com-
pound 19 in 25% yield as the main product. As expected,
the 1H NMR data of 19 were in excellent accordance with
those of their supposed diacetate of b-C-allyl 2-deoxy-ri- Vers.5.10 (Copyright 1997, Bruker Analytical X-ray Systems). All
non-hydrogen atoms were refined anisotropically. The hydrogen at-
bofuranose. Again, the publication did not provide data
oms were put into theoretical positions and refined using the riding
for optical rotation or a further evidence for the ring size
and the stereochemistry at C-1¢. Indeed, the analytical
model.21
All solutions used for washings were cooled to ~5 °C; aq sat.
data of compound 13 and 19 differ from each other signif-
22
NaHCO3 was used for washings. Reactions were monitored by TLC
(Silica Gel 60, F254, Merck KGaA). The following solvent systems
(v/v) were used: (A1) 2:1, (A2) 5:1, (A3) 6:1, (A4) 10:1, (A5) 30:1,
(A6) 50:1, (A7) 80:1, (A8) 100:1 n-hexane–EtOAc; (B) 10:1 EtOAc–
MeOH. The spots were made visible by dipping the TLC plates into
a methanolic 10% H2SO4 solution and charring with a heat gun for
3–5 min. Preparative flash chromatography was performed by elu-
tion from columns of slurry-packed Silica Gel 60 (Merck, 63–200
mm). All solvents and reagents were purified and dried according to
standard procedures.22 After classical workup of the reactions mix-
tures, the organic layers were dried over MgSO4, and then concen-
trated under reduced pressure (rotary evaporator).
icantly. For instance, the optical rotation of 13 was [a]D
+27.9, whereas 19 gave a value of [a]D22 +48.4. Further-
more, in the H NMR spectra the signal of H-1¢ of 13 at
1
d = 4.01–4.25 occurs at lower field compared to the signal
of H-1¢ at d = 3.67–3.74 of compound 19. Conspicuously,
in the 13C NMR spectra the signals of the carbon atoms C-
3¢ and C-4¢ of 13 appeared at d = 76.3 and 78.3, respec-
tively, while the signals of the same carbon atoms of 19
were assigned at d = 67.1 and 67.8, respectively. Addi-
tionally, coupling constants and results of NOESY mea-
surements led to the conclusion that compound 19 adopts
Synthesis 2009, No. 11, 1834–1840 © Thieme Stuttgart · New York

1838
H. Otero Martinez et al.
PAPER
C-Allyl Glycosides 5 and 6
3-(2,3,5-Tri-O-acetyl-b-D-ribofuranosyl)prop-1-ene (8)
Freshly distilled Ac2O (0.5 mL) was added to a stirred soln of com-
pound 7 (174 mg 1.0 mmol) in anhyd pyridine (1.0 mL) at 5 °C. The
mixture was allowed to attain r.t. and stirring was continued over-
night. For workup, the reaction mixture was poured into ice-water
(40 mL), the aqueous phase was extracted with CH2Cl2 (3 × 20 mL),
and the combined organic phases were washed successively with
cold aq NaHCO3 (2 × 20 mL), H2O (20 mL), aq 1 M HCl (2 × 20
mL), H2O (2 × 20 mL), dried, and concentrated. Purification by
flash chromatography (solvent A1) afforded compound 8 (237 mg,
Allyltrimethylsilane (10.28 g, 90.0 mmol) was added to a stirred so-
lution of 1,5-di-O-acetyl-2,3-O-isopropylidene-b-D-ribofuranose
(3; 5.49 g, 20.0 mmol) or of 1-O-acetyl-5-O-tert-butyldiphenylsi-
lyl-2,3-O-isopropylidene-b-D-ribofuranose (4; 9.41 g, 20.0 mmol)
and ZnBr2 (11.26 g, 50.0 mmol) in anhyd MeNO2 (100 mL). After
stirring for 1 h at r.t., aq sat. NaHCO3 (50 mL) was added, and the
mixture was extracted with CH2Cl2 (3 × 200 mL). The combined or-
ganic phases were dried and concentrated. The residue was then pu-
rified by flash chromatography (solvent A3 for 5 and solvent A5 for
6) to provide 5 as a colorless syrup (4.00 g, 78%) and 6 (4.98 g,
55%) as colorless crystals, respectively.
23
79%) as a colorless syrup; [a]D +18.6 (c 1.0, CH2Cl2); Rf = 0.33
(solvent A1).
1H NMR (500 MHz, CDCl3): d = 2.03 (s, 3 H), 2.03 (s, 3 H), 2.05
(s, 3 H, 3 × COCH3), 2.28–2.42 (m, 2 H, H-3), 4.01 (‘q’, 1 H,
3J1¢,2¢ = 3J1¢,3 = 5.9 Hz, H-1¢), 4.07 (dd, 3J4¢,5¢a = 4.7 Hz, 2J5¢a,5¢b = 11.4
Hz, 1 H, H-5¢a), 4.08–4.11 (m, 1 H, H-4¢), 4.28 (dd, 3J4¢,5¢b = 2.8 Hz,
2J5¢a,5¢b = 11.4 Hz, 1 H, H-5¢b), 4.95 (‘t’, 1 H, 3J2¢,3¢ = 5.9 Hz, H-2¢),
5.07–5.13 (m, 3 H, H-1, H-3¢), 5.77 (m, 1 H, H-2).
3-(5-O-Acetyl-2,3-O-isopropylidene-b-D-ribofuranosyl)prop-1-
ene (5)
The analytical data agree perfectly with those published by Fürstner
et al.10
3-(5-O-tert-Butyldiphenylsilyl-2,3-O-isopropylidene-b-D-ribo-
13C NMR (125.8 MHz, CDCl3): d = 20.5, 20.6, 20.8 (3 × COCH3),
37.1 (C-3), 63.5 (C-5¢), 71.5 (C-3¢), 73.4 (C-2¢), 79.0 (C-4¢), 80.4
(C-1¢), 118.3 (C-1), 132.7 (C-2), 169.7, 169.8, 170.6 (3 × C=O).
furanosyl)prop-1-ene (6)
Mp 73–75 °C (EtOH); [a]D21 +9.7 (c 1.0, CHCl3); Rf = 0.45 (solvent
A4).
CI-MS: m/z (%) = 301 (100, [M + H]+).
1H NMR (500 MHz, CDCl3): d = 1.08 [s, 9 H, C(CH3)3], 1.36, 1.55
[2 s, 6 H, C(CH3)2], 2.38–2.44 (m, 2 H, H-3), 3.80 (m, AB part of
ABX, 2J = 11.0 Hz, 2 H, H-5¢), 3.98 (dt, 3J1¢,2¢ = 5.0 Hz, 3J1¢,3 = 6.6
Hz, 1 H, H-1¢), 4.05 (‘q’, 3J3¢,4¢ ≈ 3J4¢,5¢a ≈ 3J4¢,5¢b ≈ 3.8 Hz, 1 H, H-4¢),
Anal. Calcd for C14H20O7 (300.30): C, 55.99; H, 6.71. Found: C,
55.91; H, 6.78.
3
3
3-[3,5-O-(Tetraisopropyldisiloxan-1,3-diyl)-b-D-ribofurano-
syl]prop-1-ene (9)
4.38 (dd, J2¢,3¢ = 6.7 Hz, 1 H, H-2¢), 4.74 (dd, J3¢,4¢ = 3.8 Hz,
3J2¢,3¢ = 6.7 Hz, 1 H, H-3¢), 5.10–5.17 (m, 2 H, H-1), 5.88 (m, 1 H,
H-2), 7.37–7.45 (m, 6 H, 2 × C6H5), 7.69–7.73 (m, 4 H, 2 × C6H5).
1,3-Dichloro-1,1,3,3-tetraisopropyldisiloxane (8.4 mL, 27.0 mmol)
was added to a soln of compound 7 (4.36 g, 25.0 mmol) in anhyd
pyridine (60 mL). After stirring at r.t. for 24 h, the reaction mixture
was diluted with EtOAc (200 mL), and the organic phase was
washed successively with ice-water (100 mL), aq 1 M HCl (2 × 100
mL), H2O (2 × 100 mL), dried, and concentrated. Purification by
flash chromatography (solvent A4) afforded compound 9 (7.08 g,
13C NMR (125.8 MHz, CDCl3): d = 19.2 [C(CH3)3], 25.6, 27.5
[2 × C(CH3)2], 26.8 [C(CH3)3], 38.1 (C-3), 64.1 (C-5¢), 81.8 (C-3¢),
83.7 (C-1¢), 84.2 (C-2¢), 84.2 (C-4¢), 114.0 [C(CH3)2], 117.4 (C-1),
127.6, 127.7 (2 × m-CH of Ph), 129.6, 129.7 (2 × p-CH of Ph),
133.2, 133.3 (2 × i-C of Ph), 134.0 (C-2), 135.6, 135.6 (2 × o-CH of
Ph).
24
68%) as a colorless syrup; [a]D –20.7 (c 1.0, CH2Cl2); Rf = 0.48
Anal. Calcd for C27H36O4Si (452.66): C, 71.64; H, 8.02. Found: C,
71.56; H, 8.31.
(solvent A2).
1H NMR (300 MHz, CDCl3): d = 0.90–1.11 [m, 28 H,
4 × CH(CH3)2], 2.25–2.44 (m, 2 H, H-3), 2.82 (d, 3J2¢,OH = 3.7 Hz, 1
H, OH-2¢), 3.75–3.90 (m, 3 H, H-1¢, H-2¢, H-4¢), 3.87 (dd,
3J4¢,5¢a = 6.0 Hz, 2J5¢a,5¢b = 11.9 Hz, 1 H, H-5¢a), 4.00 (dd, 3J4¢,5¢b = 3.2
Hz, 1 H, H-5¢b), 4.18 (‘t’, 3J2¢,3¢ = 3J3¢,4¢ = 6.4 Hz, 1 H, H-3¢), 5.05–
5.16 (m, 2 H, H-1), 5.86 (m, 1 H, H-2).
13C NMR (75.5 MHz, CDCl3): d = 12.6, 12.8, 13.2, 13.4
[4 × CH(CH3)2], 16.9, 17.0, 17.0, 17.1, 17.2, 17.3, 17.3, 17.4
[8 × CH(CH3)2], 37.7 (C-3), 62.7 (C-5¢), 72.2 (C-3¢), 73.8 (C-2¢),
82.2, 83.4 (C-1¢, C-4¢), 117.5 (C-1), 133.9 (C-2).
3-(b-D-Ribofuranosyl)prop-1-ene (7)
From 5: Aq HCl (0.1 M, 30 mL) was added to a soln of compound
5 (14.61 g, 57.0 mmol) in EtOH (25 mL), and the mixture was
stirred for 2 d at r.t. (monitored by TLC). The mixture was then neu-
tralized by the addition of solid NaHCO3, and concentrated after ad-
dition of a small amount of silica gel (suitable for flash
chromatography). The residue was purified by flash chromatogra-
phy (solvent A4) to afford compound 7 (7.94 g, 80%) as a colorless
syrup.
CI-MS: m/z (%) = 417 (100, [M + H]+).
From 6: A soln of TBAF in 1,4-dioxane (0.1 M, 7.3 mL) was added
dropwise to a soln of compound 6 (2.26 g, 5.0 mmol) in 1,4-dioxane
(73 mL) at r.t. The mixture was stirred at r.t. for 24 h, and concen-
trated. After dissolving the residue in EtOH (30 mL), aq 0.1 M HCl
(10 mL) was added and the mixture was stirred for 24 h at r.t. The
workup was done in the same way as described above to provide 7
(653 mg, 75%); [a]D23 –4.6 (c 1.0, MeOH); Rf = 0.35 (solvent B).
1H NMR (250 MHz, DMSO-d6): d = 2.09–2.34 (m, 2 H, H-3), 3.30–
3.45 (m, 2 H, H-5¢), 3.52 (m, 1 H, H-1¢), 3.64–3.48 (m, 2 H, H-2¢,
H-4¢), 3.72 (m, 1 H, H-3¢), 4.58 (t, 3J5¢,OH = 5.7 Hz, 1 H, OH-5¢), 4.67
(br, 1 H), 4.69 (br, 1 H, OH-2¢, OH-3¢), 4.97–5.11 (m, 2 H, H-1),
5.83 (m, 1 H, H-2).
Anal. Calcd for C20H40O5Si2 (416.70): C, 57.65; H, 9.68. Found: C,
57.41; H, 9.75.
3-[2-Deoxy-2-iodo-3,5-O-(tetraisopropyldisiloxane-1,3-diyl)-b-
D-arabinofuranosyl]prop-1-ene (10)
A mixture of compound 9 (1.04 g, 2.5 mmol), Ph3P (1.65 g, 6.3
mmol), imidazole (436 mg, 6.4 mmol), and I2 (947 mg, 7.5 mmol)
in toluene (30 mL) was heated under reflux for 5–6 h (monitored by
TLC). The reaction mixture was cooled to r.t., aq sat. NaHCO3 (50
mL) was added, and the mixture was stirred for 5 h. The toluene
phase was then separated and concentrated. Flash chromatography
(solvent A8) of the residue provided compound 10 (1.32 g, 95%) as
a colorless syrup; [a]D –72.3 (c 1.0, CH2Cl2); Rf = 0.32 (solvent
A6).
1H NMR (300 MHz, CDCl3): d = 1.00–1.10 [m, 28 H,
13C NMR (62.9 MHz, DMSO-d6): d = 37.7 (C-3), 62.2 (C-5¢), 71.2
(C-3¢), 74.0 (C-1¢), 81.6, 84.5 (C-2¢, C-4¢), 116.8 (C-1), 135.5 (C-2).
ESI-MS (+): m/z = 197 [M + Na]+.
24
3
Anal. Calcd for C8H14O4 (174.19): C, 55.16; H, 8.10. Found: C,
55.07; H, 7.84.
4 × CH(CH3)2], 2.40 (m, 2 H, H-3), 3.19 (dt, J1¢,2¢ = 3.8 Hz,
3J1¢,3 = 6.7 Hz, 1 H, H-1¢), 3.78 (d‘t’, 3J3¢,4¢ = 3.5 Hz, 3J4¢,5¢b = 4.0 Hz,
Synthesis 2009, No. 11, 1834–1840 © Thieme Stuttgart · New York

PAPER
Peracetylated b-Allyl C-Glycosides
EI-MS: m/z (%) = 242 (1, [M]+).
1839
3J4¢,5¢a = 9.8 Hz, 1 H, H-4¢), 3.93 (dd, 2J5¢a,5¢b = 11.0 Hz, 1 H, H-5¢a),
4.17 (dd, 3J4¢,5¢b = 4.0 Hz, 1 H, H-5¢b), 4.24 (dd, 3J2¢,3¢ = 1.6 Hz, 1 H,
H-2¢), 4.92 (dd, 3J3¢,4¢ = 3.5 Hz, 1 H, H-3¢), 5.10–5.27 (m, 2 H, H-1),
5.80 (m, 1 H, H-2).
Anal. Calcd for C12H18O5 (242.27): C, 59.49; H, 7.49. Found: C,
59.44; H, 7.71.
13C NMR (75.5 MHz, CDCl3): d = 12.4, 13.1, 13.4, 13.6
[4 × CH(CH3)2], 16.9, 17.0, 17.0, 17.2, 17.4 (two signals are iso-
chronic), 17.5, 17.5 [8 × CH(CH3)2], 38.6 (C-2¢), 41.2 (C-3), 65.6
(C-5¢), 78.9 (C-1¢), 87.3 (C-4¢), 84.4 (C-3¢), 118.0 (C-1), 133.3 (C-2).
O-Acetates 14 and 15
Freshly distilled Ac2O (25 mL) was added at 0 °C to a stirred soln
of D-ribose (4.5 g, 30.0 mmol) or D-deoxyribose in anhyd pyridine
(50 mL). After stirring for 12 h at r.t., the reaction mixture was
poured into ice-water (100 mL). The aqueous layer was extracted
with CH2Cl2 (3 × 120 mL) and the combined organic layers were
washed successively with aq 3% HCl (100 mL), ice-water (100
mL), aq sat. NaHCO3 (100 mL) and ice-water (100 mL), dried, and
concentrated.
ESI-MS (+): m/z = 527 [M + H]+.
Anal. Calcd for C20H39IO4Si2 (526.60): C, 45.62; H, 7.46. Found: C,
45.53; H, 7.51.
3-[2-Deoxy-3,5-O-(tetraisopropyldisiloxane-1,3-diyl)-b-D-
erythro-pentofuranosyl]prop-1-ene (11)
3-(2,3,4-Tri-O-acetyl-a-D-ribopyranosyl)prop-1-ene (16)
A mixture of compound 10 (790 mg, 1.5 mmol), Bu3SnH (873 mg,
3,0 mmol), and azobisisobutyronitrile (AIBN, 49 mg, 0.3 mmol) in
toluene (20 mL) was stirred under reflux for 5 h, after which addi-
tional Bu3SnH (437 mg, 1,5 mmol) and AIBN (49 mg, 0.3 mmol)
were added. Stirring under reflux was continued for further 5 h, and
the reaction mixture was then concentrated. Purification by flash
chromatography (solvent A7) afforded compound 11 (421 mg, 70%)
as a colorless syrup; [a]D23 –13.2 (c 1.0, CH2Cl2); Rf = 0.27 (solvent
A6).
TMSOTf (1.89 g, 8.5 mmol) was added dropwise to a soln of
1,2,3,4-tetra-O-acetyl-D-ribose (mixture of 14f and 14p, 2.23 g, 7.0
mmol) and allyltrimethylsilane (3.2 mL, 20 mmol) in anhyd MeCN
(20 mL) at 0 °C. The ice bath was removed, and the mixture was
stirred for 6 h at r.t. Cold aq sat. NaHCO3 (50 ml) was then added
and the aqueous phase was extracted with CH2Cl2 (3 × 100 mL).
The combined organic phases were washed with brine (2 × 100
mL), dried, and concentrated. Purification by flash chromatography
(solvent A2) afforded compound 16 (946 mg, 45%) as colorless
crystals. The synthesis corresponds to the procedure described in
the literature4 for the alleged preparation of compound 8; mp 80 °C
(EtOAc); [a]D23 –0.7 (c 1.0, CH2Cl2); Rf = 0.21 (solvent A2).
1H NMR (300 MHz, CDCl3): d = 0.99–1.09 [m, 28 H,
3
2
4 × CH(CH3)2], 1.81 (d‘t’, J1¢,2¢a = 3J2¢a,3¢ = 7.8 Hz, J2¢a,2¢b = 12.5
Hz, 1 H, H-2¢a), 2.00 (ddd, 3J2¢b,3¢ = 4.5 Hz, 3J1¢,2¢b = 6.6 Hz, 1 H, H-
2¢b), 2.18–2.37 (m, 2 H, H-3), 3.68–3.77 (m, 2 H, H-4¢, H-5¢a),
3.98–4.06 (m, 1 H, H-5¢b), 4.12 (m, 1 H, H-1¢), 4.36 (d‘t’,
3J2¢b,3¢ = 4.5 Hz, 3J2¢a,3¢ = 3J3¢,4¢ = 7.8 Hz, 1 H, H-3¢), 5.02–5.12 (m, 2
H, H-1), 5.80 (m, 1 H, H-2).
1H NMR (300 MHz, CDCl3): d = 1.98, 2.13, 2.15 (3 s, 9 H,
2 × COCH3), 2.18–2.27, 2.40–2.46 (2 m, 2 H, H-3), 3.53 (ddd,
3J1¢,2¢ = 1.2 Hz, 3J1¢,3b = 6.0 Hz, 3J1¢,3a = 7.8 Hz, 1 H, H-1¢), 3.68 (dd,
3
2
1 H, J4¢,5¢ax = 1.5 Hz, J5¢ax,5¢eq = 13.7 Hz, H-5¢ax), 4.11 (dd,
3J4¢,5¢eq = 1.8 Hz, 1 H, H-5¢eq), 5.05 (‘t’, 3J2¢,3¢ = 3J3¢,4¢ = 3.8 Hz, 1 H,
H-3¢), 5.05–5.10 (m, 2 H, H-1), 5.15 (m, 1 H, H-4¢), 5.21 (m, 1 H,
H-2¢), 5.75 (m, 1 H, H-2).
13C NMR (75.5 MHz, CDCl3): d = 12.6, 12.9, 13.4, 13.5
[4 × CH(CH3)2], 17.0, 17.0, 17.1, 17.3, 17.4, 17.4 (two signals are
isochronic), 17.5 [8 × CH(CH3)2], 39.7 (C-2¢), 39.8 (C-3), 63.8 (C-
5¢), 73.5 (C-3¢), 76.9 (C-1¢), 85.9 (C-4¢), 117.2 (C-1), 134.3 (C-2).
13C NMR (75.5 MHz, CDCl3): d = 20.6, 20.7, 21.0 (3 × COCH3),
35.4 (C-3), 66.7 (C-4¢), 67.8 (C-2¢), 68.3 (C-3¢), 69.0 (C-5¢), 77.5
(C-1¢), 118.3 (C-1), 132.9 (C-2), 169.8, 170.3, 170.4 (3 × C=O).
ESI-MS (+): m/z = 401 [M + H]+.
Anal. Calcd for C20H40O4Si2 (400.70): C, 59.95; H, 10.06. Found:
C, 60.03; H, 9.81.
CI-MS: m/z (%) = 301 (100, [M + H]+).
Anal. Calcd for C14H20O7 (300.30): C, 55.99; H, 6.71. Found: C,
56.26; H 6.78.
3-(2-Deoxy-3,5-di-O-acetyl-b-D-erythro-pentofuranosyl)prop-1-
ene (13)
A soln of TBAF in 1,4-dioxane (1.0 M, 0.4 mL) was added drop-
wise to a soln of compound 11 (100 mg, 0.25 mmol) in 1,4-dioxane
(3.0 mL) at r.t. The reaction mixture was stirred at r.t. for 5 h, and
then concentrated. The residue (compound 12) was dissolved in an-
hyd pyridine (0.5 mL) and freshly distilled Ac2O (0.25 mL) was
added, and the obtained soln was stirred overnight at r.t.. The mix-
ture was then poured into ice-water (20 mL), the aqueous phase was
extracted with CH2Cl2 (3 × 15 mL), and the combined organic phas-
es were washed successively with cold aq NaHCO3 (2 × 15 mL),
H2O (15 mL), aq 1 M HCl (2 × 15 mL), H2O (2 × 15 mL), dried, and
concentrated. Purification by flash chromatography (solvent A2) af-
3-(a-D-Ribopyranosyl)prop-1-ene (17)
Methanolic NaOMe (0.5 M, 0.15 mL) was added to a soln of com-
pound 16 (905 mg, 3.0 mmol) in anhyd MeOH (7 mL). After stir-
ring at r.t. for 2 h, the reaction mixture was neutralized with IR 120
(H+) Amberlite resign, filtered, dried, and concentrated. Flash chro-
matography (solvent B) of the residue provided compound 17 (525
24
mg, 98%) as colorless crystals; mp 155 °C; [a]D –11.8 (c 1.0,
CH3OH); Rf = 0.29 (solvent B).
1H NMR (300 MHz, DMSO-d6): d = 2.27 (m, 2 H, H-3), 3.22 (ddd,
3J1¢,2¢ = 1.1 Hz, 3J1¢,3b = 6.2 Hz, 3J1¢,3a = 7.5 Hz, 1 H, H-1¢), 3.37 (dd,
3J4¢,5¢ax = 1.0 Hz, 2J5¢ax,5¢eq = 12.0 Hz, 1 H, H-5¢ax), 3.41 (br, 1 H, H-
3¢), 3.47 (m, 1 H, H-2¢), 3.60 (br, 1 H, H-4¢), 3.75 (dd, 3J4¢,5¢eq = 2.2
Hz, 1 H, H-5¢eq), 4.59 (d, 3J2¢,OH = 7.5 Hz, 1 H, OH-2¢), 4.88 (br s,
1 H, OH-3¢), 4.97–5.09 (m, 2 H, H-1), 5.06 (br d, 3J4¢,OH = 6.2 Hz, 1
H, OH-4¢), 5.78 (m, 1 H, H-2).
13C NMR (62.9 MHz, DMSO-d6): d = 35.5 (C-3), 68.7 (C-3¢), 69.3
(C-4¢), 70.6 (C-5¢), 70.9 (C-2¢), 78.2 (C-1¢), 116.7 (C-1), 135.4 (C-
2).
22
forded compound 13 (50 mg, 83%) as a colorless syrup; [a]D
+27.9 (c 0.9, CH2Cl2); Rf = 0.22 (solvent A2).
3
1H NMR (250 MHz, CDCl3): d = 1.79 (ddd, J2¢a,3¢ = 6.4 Hz,
2
3J1¢,2¢a = 10.4 Hz, J2¢a,2¢b = 13.7 Hz, 1 H, H-2¢a), 1.99 (ddd,
3
3J2¢b,3¢ = 1.5 Hz, J1¢,2¢b = 5.2 Hz, 1 H, H-2¢b), 2.04, 2.06 (2 s, 6 H,
2 × COCH3), 2.22–2.47 (m, 2 H, H-3), 4.01–4.25 (m, 4 H, H-1¢, H-
4¢, H-5¢), 5.04–5.14 (m, 3 H, H-1, H-3¢), 5.78 (m, 1 H, H-2).
13C NMR (62.9 MHz, CDCl3): d = 20.8, 21.0 (2 × COCH3), 37.5,
39.1 (C-2¢, C-3), 64.4 (C-5¢), 76.3 (C-3¢), 78.3 (C-4¢), 82.1 (C-1¢),
117.5 (C-1), 133.8 (C-2), 170.5, 170.7 (2 × C=O).
CI-MS: m/z (%) = 197 (100, [M + Na]+).
Anal Calcd for C8H14O4 (174.19): C, 55.16; H, 8.10. Found: C,
55.39; H 8.37.
Synthesis 2009, No. 11, 1834–1840 © Thieme Stuttgart · New York

1840
H. Otero Martinez et al.
PAPER
3-[3,4-O-(Tetraisopropyldisiloxane-1,3-diyl)-a-D-ribopyrano-
syl]prop-1-ene (18)
Starting from compound 17 (525 mg, 3.0 mmol), compound 18 (963
mg, 77%) was obtained as colorless crystals according to the proce-
dure described for compound 9; mp 56–58 °C; [a]D23 –27.3 (c 1.0,
CH2Cl2); Rf = 0.41 (solvent A4).
1H NMR (300 MHz, CDCl3): d = 1.02–1.08 [m, 28 H,
4 × CH(CH3)2], 2.48 (m, 2 H, H-3), 3.20 (d, 3J2¢,OH = 10.5 Hz, 1 H,
OH-2¢), 3.26 (ddd, 3J1¢,2¢ = 1.1 Hz, 3J1¢,3b = 6.5 Hz, 3J1¢,3a = 7.5 Hz, 1
H, H-1¢), 3.55 (dd, 3J4¢,5¢ax = 1.3 Hz, 2J5¢ax,5¢eq = 12.4 Hz, 1 H,H-5¢ax),
3.67 (m, 1 H, H-2¢), 3.89 (‘t’, 3J2¢,3'¢ ≈ 3J3¢,4¢ = 3.2 Hz, 1 H, H-3¢), 4.04
(dd, 3J4¢,5¢eq = 2.2 Hz, 1 H, H-5¢eq), 4.18 (m, 1 H, H-4¢), 5.05–5.17
(m, 2 H, H-1), 5.83 (m, 1 H, H-2).
13C NMR (75.5 MHz, CDCl3): d = 12.5, 12.6, 13.6, 14.2
[4 × CH(CH3)2], 17.0, 17.1, 17.2, 17.3, 17.3, 17.6, 17.6, 17.6
[8 × CH(CH3)2], 35.8 (C-3), 71.0 (C-5¢), 71.6, 71.7, 73.5 (C-2¢, C-
3¢, C-4¢), 80.0 (C-1¢), 117.4 (C-1), 134.5 (C-2).
References
(1) Present address: University Karlsruhe, Institute of Organic
Chemistry, Fritz-Haber-Weg 6, 76131, Karlsruhe, Germany.
(2) Boal, J. H.; Wilk, A.; Scremin, C. L.; Gray, G. N.; Philips,
L. R.; Beaucage, S. L. J. Org. Chem. 1996, 61, 1687.
(3) Hossain, N.; Blaton, N.; Peeters, O.; Rozenski, J.;
Herdewijn, P. A. Tetrahedron 1996, 52, 5563.
(4) McDevitt, J. P.; Lansbury, P. T. Jr. J. Am. Chem. Soc. 1996,
118, 3818.
(5) Levene, P. A.; Stiller, E. T. J. Biol. Chem. 1933, 102, 187.
(6) Kiso, M.; Hasegawa, A. Carbohydr. Res. 1976, 52, 95.
(7) Kaskar, B.; Heise, G. L.; Michalak, R. S.; Vishnuvajjala,
B. R. Synthesis 1990, 1031.
(8) Lloyd, A. E.; Coe, P. L.; Walker, R. T.; Howarth, O. W.
J. Fluorine Chem. 1993, 60, 239.
(9) Wilcox, C. S.; Otoski, R. M. Tetrahedron Lett. 1986, 27,
1011.
(10) Fürstner, A.; Radkowski, K.; Wirtz, C.; Goddard, R.;
Lehmann, C. W.; Mynott, R. J. Am. Chem. Soc. 2002, 124,
7061.
(11) Barton, D. H. R.; McCombie, S. W. J. Chem. Soc., Perkin
Trans. 1 1975, 1574.
CI-MS: m/z (%) = 417 (100, [M + H]+).
Anal. Calcd for C20H40O5Si2 (416.70): C, 57.65; H, 9.68. Found: C,
57.53; H, 9.95.
3-(2-Deoxy-3,4-di-O-acetyl-a-D-ribopyranosyl)prop-1-ene (19)
For transformation of 1,3,4-tri-O-acetyl-2-desoxy-D-ribose (mix-
ture of 15f and 15p, 520 mg, 2.0 mmol) into compound 18 condi-
tions of McDevitt and Lansbury, Jr.4 were used again (see
preparation of 16). Purification by flash chromatography (solvent
A2) afforded the main product 19 (121 mg, 25%) of the reaction as
(12) Genu-Dellac, C.; Gosselin, G.; Imbach, J.-L. Carbohydr.
Res. 1991, 216, 249.
(13) Jun, S. J.; Moon, M. S.; Lee, S. H.; Cheong, C. S.; Kim,
K. S. Tetrahedron Lett. 2005, 46, 5063.
(14) Garegg, P. J.; Samuelsson, B. J. Chem. Soc., Perkin Trans. 1
1980, 2866.
(15) Gimisis, T.; Ialongo, G.; Chatgilialoglu, C. Tetrahedron
1998, 54, 573.
(16) Diederichsen, U.; Biro, C. M. Biorg. Med. Chem. Lett. 2000,
10, 1417.
(17) Zinner, H. Chem. Ber. 1953, 86, 817.
(18) Kam, B. L.; Barascut, J.-L.; Imbach, J.-L. Carbohydr. Res.
1980, 78, 285.
22
a colorless syrup; [a]D +48.4 (c 0.5, CH2Cl2); Rf = 0.26 (solvent
A2).
3
1H NMR (500 MHz, CDCl3): d = 1.65 (ddd, J2¢ax,3¢ = 2.5 Hz,
2
3J1¢,2¢ax = 11.4 Hz, J2¢ax,2¢eq = 14.5 Hz, 1 H, H-2¢ax), 1.87 (ddd,
3J1¢,2¢eq = 2.0 Hz, 3J2¢eq,3¢ = 3.8 Hz, 1 H, H-2¢eq), 1.99, 2.10 (2 s, 6 H,
2 × COCH3), 2.16–2.30 (m,
2
H, H-3), 3.67 (‘t’,
3J4¢,5¢ax = 2J5¢ax,5¢eq = 10.7 Hz, 1 H, H-5¢ax), 3.67–3.74 (m, 1 H, H-1¢),
3.80 (ddd, 3J4¢,5¢eq = 5.4 Hz, 4J3¢,5¢eq = 1.2 Hz, 1 H, H-5¢eq), 4.88 (ddd,
3J3¢,4¢ = 3.0 Hz, 1 H, H-4¢), 5.05–5.10 (m, 2 H, H-1), 5.40 (m, 1 H,
H-3¢), 5.79 (m, 1 H, H-2).
(19) Patnam, R.; Juarez-Ruiz, J. M.; Roy, R. Org. Lett. 2006, 8,
2691.
(20) Venner, H.; Zinner, H. Chem. Ber. 1960, 93, 137.
(21) Crystallographic data for the structural analysis has been
deposited with the Cambridge Crystallographic Data Centre
under CCDC No. 717935 and 717936 for compounds 6 and
18, respectively. Copies of this information may be obtained
free of charge from: The Director, CCDC, 12 Union Road,
Cambridge, CB2 1EZ UK. Fax: +44(1223)336033 or via
e-mail: deposit@ccdc.cam.ac.uk or
13C NMR (125.8 MHz, CDCl3): d = 20.8, 21.0 (2 × COCH3), 34.9
(C-2¢), 39.5 (C-3), 63.9 (C-5¢), 67.1 (C-3¢), 67.8 (C-4¢), 71.5 (C-1¢),
117.4 (C-1), 134.1 (C-2), 169.9, 170.1 (2 × C=O).
EI-MS: m/z (%) = 242 (1, [M]+).
HRMS: m/z calcd for C12H18O5: 242.1142, found: 242.1149.
http://www.ccdc.cam.ac.uk.
(22) Perrin, D. D.; Armarego, W. L. F. Purification of Laboratory
Chemicals, 3rd ed.; Pergamon Press: Oxford, 1988.
Acknowledgment
This work has been supported by Research Training Group 1213
‘New Methods for Sustainability in Catalysis and Technique’
(DFG). Further we would like to thank Prof. Dr. Udo Kragl for sup-
port and fruitful discussions.
Synthesis 2009, No. 11, 1834–1840 © Thieme Stuttgart · New York