Organotransition metal modified sugars: Part 22. Direct metalation of glycals: Short and efficient routes to diversely protected stannylated glycals

Article abstract of DOI:10.1016/S0022-328X(00)00920-7

A complete set of D-hexose-derived silyl and isopropylidene/silyl-protected glycals bearing complementary configurations at C-3 and C-4 has been synthesized in short and efficient 1-3 step sequences from standard precursors. The glycals have been applied to metalation reactions to give storable vinyl lithium equivalents by subsequent transmetalation to vinyl stannanes which represent valuable intermediates for transition metal-catalyzed cross-coupling reactions. A ¹H-NMR-assisted conformational analysis has been carried out with the protected glycals and the stannylated congeners. The isopropylidene/silyl-protected glycals adopt the ₄H₅-conformation caused by the bicyclic system, whereas the conformations of the fully silyl-protected monocyclic glycals are mainly controlled by the vinylogous anomeric effect. The discussed galactal- and allal-derivatives show dynamic behaviour on the NMR-time-scale. At low temperatures the two possible conformers (⁴H₅ and ⁵H₄) have been observed demonstrating competition of steric congestion and stereoelectronic interaction via the vinylogous anomeric effect (VAE).

Full text of DOI:10.1016/S0022-328X(00)00920-7

Journal of Organometallic Chemistry 624 (2001) 172–185
www.elsevier.nl/locate/jorganchem
Organotransition metal modified sugarsꢀ
Part 22. Direct metalation of glycals: short and efficient routes to
diversely protected stannylated glycals
Christoph Ja¨kel, Karl Heinz Do¨tz *
Kekule´-Institut fu¨r Organische Chemie und Biochemie, Rheinische Friedrich-Wilhelms-Uni6ersita¨t, Gerhard-Domagk-Strasse 1,
D-53121 Bonn, Germany
Received 6 October 2000; accepted 27 November 2000
Dedicated to Professor Jean Normant on the occasion of his 65th birthday
Abstract
A complete set of D-hexose-derived silyl and isopropylidene/silyl-protected glycals bearing complementary configurations at C-3
and C-4 has been synthesized in short and efficient 1–3 step sequences from standard precursors. The glycals have been applied
to metalation reactions to give storable vinyl lithium equivalents by subsequent transmetalation to vinyl stannanes which represent
1
valuable intermediates for transition metal-catalyzed cross-coupling reactions. A H-NMR-assisted conformational analysis has
been carried out with the protected glycals and the stannylated congeners. The isopropylidene/silyl-protected glycals adopt the
4H5-conformation caused by the bicyclic system, whereas the conformations of the fully silyl-protected monocyclic glycals are
mainly controlled by the vinylogous anomeric effect. The discussed galactal- and allal-derivatives show dynamic behaviour on the
5
NMR-time-scale. At low temperatures the two possible conformers (4H5 and H4) have been observed demonstrating competition
of steric congestion and stereoelectronic interaction via the vinylogous anomeric effect (VAE). © 2001 Elsevier Science B.V. All
rights reserved.
Keywords: Carbohydrates; C-glycosidation; Glycals; Organostannanes
blocks [8]. However, the direct metalation at C-1 is
hampered and impedes broader applications in this
context. The limitations in the choice of different func-
tional and even protective groups and the harsh depro-
1. Introduction
Metalated glycals have been developed to versatile
synthons in the synthesis of C-glycosides [1]. The struc-
tural diversity of target molecules synthesized or elabo-
rated via metalated glycals covers C-aryl glycosidic
structures [2] such as vineomycins [3], aquayamycin [4]
or papulacandins [5] as well as fused pyran structures
represented by herbicidins [6] or — more complex —
by marine polyether antibiotics such as brevetoxins [7]
(Scheme 1). Due to the easy access of a broad variety of
glycals from naturally abundant carbohydrates they
represent important enantiomerically pure building
tonation
conditions
required
encouraged
the
development of alternative approaches to this type of
compounds. A three-step procedure introduced by Ley
[9] involves the activation of the anomeric position by
addition of phenylsulfinic acid, subsequent deprotona-
tion/stannylation followed by elimination of phenyl-
sulfinic acid. The resulting stannane derivatives have
been transmetalated to the lithio compounds and em-
ployed in Pd-catalyzed homocoupling reactions. The
activated sulfone has been also obtained from lactones
in a two-step procedure involving reduction to the
lactol and substitution with phenylsulfinic acid. Lac-
tones are the starting point of a second versatile
method introduced by Kocienski [10] to avoid a direct
metalation. Preparation of the enol triflate [11] and
ꢀ For part 21 see: E. Jones, K.H. Do¨tz, J. Organomet. Chem.,
accepted for publication.
* Corresponding author. Tel.: +49-228-735609; fax: +49-228-
735813.
E-mail address: doetz@uni-bonn.de (K.H. Do¨tz).
0022-328X/01/$ - see front matter © 2001 Elsevier Science B.V. All rights reserved.
PII: S0022-328X(00)00920-7

C. Ja¨kel, K.H. Do¨tz / Journal of Organometallic Chemistry 624 (2001) 172–185
173
subsequent Stille-coupling with hexamethyldistannane
[12] provides a two-step access to stannylated glycals.
However, the 2-deoxy lactones required for their syn-
thesis have to be prepared from the corresponding
glycals in a two-step sequence [13], extending this ap-
proach to a very mild but rather lengthy four-step
procedure. Recently, Nicolaou [14] introduced enol
phosphonates for compounds with ring sizes larger
than six which are usually difficult to obtain via the
triflate route [15].
sary in the presence of a primary hydroxy functionality.
Friesen has shown for two glucal derivatives that high
conversions to the lithioglucals require up to four
equivalents of tert-butyllithium [16a]. This becomes an
obvious problem when more complex and/or expensive
electrophiles have to be used [2e,18c]. For this reason, it
is advantageous to purify the resulting lithioglycal by
transmetalation to the tri-n-butyl tin derivative, and,
finally, to regenerate the lithioglycal by an additional
transmetalation using n-butyllithium [6,19].
While the direct metalation of glucals and 6-deoxy
glycals is well-known, the appropriate protection of
galactal turns out to be problematic [18c], and to our
knowledge there is no report of a direct metalation of
an allal- or gulal-derivative at C-1. In this work we
focus on the synthesis of fully silyl-protected and 4,6-
isopropylidene-3-silylated glycals, their behaviour under
the stannylation conditions and their conformation as a
result of the protective group periphery.
Thus, while efficient though lengthy and often low-
yield alternative methods have been developed, we still
considered the direct metalation approach to be benefi-
cial if some major disadvantages could be overcome.
2. Preparation of fully protected glycals
The multiple oxygen substitution pattern in glycals
requires efficient protective groups. Only a few of them
[16] are compatible with the metalation protocol
[16a,17]. Thus, a tailored protection of the various
hydroxy functionalities may be a challenge. Moreover,
the metalation protocol demands a large excess of the
metalating agent. Already Boeckmann noticed in an
early work [17a] that two equivalents of tert-butyl-
lithium are required for the effective metalation of
cyclic enol ethers bearing an additional protected hy-
droxy group. A variety of 6-deoxy glycals have been
metalated under identical conditions [2a,18]; however,
an additional equivalent of tert-butyllithium is neces-
While the preparation of the tris-triisopropylsilyl
(TIPS)-protected glucal is known [16a], the per-TIPS
protection of
D-galactal has not been reported so far
and is suggested to be highly unfavourable. Since the
per-tert-butyldimethylsilyl (TBS)-protected galactal
tends to competing a-silyl deprotonation at the 6-posi-
tion [16b] the primary hydroxyl functionality has to be
protected with a more bulky silyl protective group.
Thus, we started from the known 6-TIPS derivative 3
[20] and installed the less bulky TBS groups at the 3-
and 4-position under forcing conditions, providing the
fully protected galactal derivative 4 in good yield
(Scheme 2).
Scheme 1. Prominent natural products with C-glycosidic linkages.

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C. Ja¨kel, K.H. Do¨tz / Journal of Organometallic Chemistry 624 (2001) 172–185
Scheme 2. Synthesis of protected glucals and galactals 2, 4, 9 and 10. Reaction conditions: (a) TBSCl, imidazole, DMF, 60–80°C, 24 h. (b) 1)
MeOH, LiOH, room temperature, 2 h, then NH4Cl; 2) 2-methoxypropene, CSA, DMF, room temperature, 1 h. (c) 1) 3.2 eq. C8K, THF, −40
to −20°C, 1.5 h; 2) 2.2 eq. TIPSCl, −20°C to room temperature, 1 h.
Recently, we introduced [16d] the isopropylidene
group as a new cyclic protective group for the 4,6-posi-
tion as an alternative to the expensive bis(tert-bu-
tyl)silylene group [16c]. Acid catalyzed introduction of
an isopropylidene protective group is well-documented
[21], but less suitable for acid-labile substrates. Further-
more, the kinetic protection of galactal results in in-
complete regiochemistry [22]. Hoping to avoid the
tedious purification problems and variable yields ac-
companied with the acid-catalyzed protection at the
glycal stage [23], we decided to introduce the protective
groups prior the formation of the glycal. Starting from
the known phenylthio glycosides 5 and 6 [24], deacety-
lation and isopropylidenation proceeded in a ‘one-pot’
procedure in excellent yields. Unveiling the hidden
carbanion present in the thioglycoside by reductive
lithiation [25] should result in the formation of a metal
alkoxide by a fragmentation of the labile anomeric
carbanion. Intercepting of the alkoxide by a silylating
agent offers the opportunity to protect the free hydrox-
ide in the same step. Both, lithium–naphthalenide and
graphite–potassium laminate have been reported to
initiate this kind of transformation [26]. For our pur-
poses, we found Fu¨rstner’s C8K procedure superior
because of reproducible yields and the enhanced reac-
tivity of the potassium alkoxide in the silylation reac-
tion. In the event, glucal 9 and galactal 10 have been
obtained in satisfying yields (Scheme 2). This easy
two-step sequence may be a valuable alternative for the
facile access to differently protected glycals.
of galactal, a straightforward strategy would employ an
epimerization procedure at this stereocenter. Due to the
allylic position to an enol ether double bond, an SN2
process would be highly unfavourable, and substitution
would preferentially occur at C-1 [28]. As a conse-
quence, an allylic substitution occurs which is known in
carbohydrate chemistry as the Ferrier-rearrangement
[29]. To our knowledge, the most effective epimeriza-
tion protocol [27e,30] makes use of the thio-Ferrier-re-
action [31] obtaining the allylic a-sulfides as major
products. Subsequent oxidation to the sulfoxides and
shifting the sulfoxide–sulfenate equilibrium [32] by in-
tercepting the sulfenates with diethylamine results in the
isolation of the rearranged allylic alcohols [33].
Starting from the known pseudo-glycals [28,30a] 11
and 12 oxidation with dimethyl dioxirane (DMDO) [34]
at low temperatures and subsequent [2,3]-sigmatropic
rearrangement proceeded very cleanly in excellent yield.
Oxidation may be even performed with MCPBA at low
temperatures [35], however, the yields are lower and
m-chloro-benzoate glycosides were identified as side
products indicating the high reactivity of the anomeric
sulfoxides as glycosyl donors. The allo-derivative was
obtained as a 1:0.15:0.1 mixture of regioisomeric diac-
etates with the 3,6-diacetate as the major product. This
result is in agreement with Danishefsky’s observation
[27e], under the slightly basic rearrangement conditions
a transacetalization between cis-diols is favourable.
Deacetylation and per-TIPS protection were performed
as
a
‘one-pot’ process; triisopropylsilyl triflate
Allals and gulals are not readily available because of
the relative rareness of allose and gulose [27]. Since allal
is the C-3 epimer of glucal and gulal is the C-3 epimer
(TIPSOTf) was required to secure complete silylation.
Due to the low solubility of the unprotected glycals in
CH2Cl2, a small amount of DMF was added as solubi-

C. Ja¨kel, K.H. Do¨tz / Journal of Organometallic Chemistry 624 (2001) 172–185
175
Scheme 3. Synthesis of protected allals and gulals 19–22. Reaction conditions: (a) 1) MeOH, LiOH, room temperature, 1 h, then NH4Cl; 2)
2-methoxypropene, CSA, DMF, room temperature, 2 h. (b) 1) DMDO, CH2Cl2, −78°C, 1 h; 2) Et2NH, THF, room temperature, overnight. (c)
1) MeOH, LiOH, room temperature, 2 h, then NH4Cl; 2) TIPSOTf, 2,6-lutidine, CH2Cl2, room temperature (to 40°C for the allo-isomer), 60 h.
(d) TIPSOTf, 2,6-lutidine, CH2Cl2, 0°C to room temperature, 3 h.
lizer. While the gulal reacted quite well, the final silyla-
tion of the allal derivative required more forcing condi-
tions reflecting the relative steric bulk resulting from the
cis-relationship of the 3- and 4-hydroxyl groups. Never-
theless, both gulal 19 and allal 20 were obtained in
good yields according to this procedure (Scheme 3).
Similarly, the isopropylidene protected allal and gulal
derivatives 21 and 22 are accessible in excellent yields
from the pseudoglycals 11 and 12. Deacetylation and
isopropylidenation were performed as described for 5
and 6 to yield 13 and 14 [36]. DMDO-oxidation and
subsequent rearrangement proceeded under the condi-
tions described above in excellent yields. Noteworthy in
this context is the relative stability of the sulfoxide
derived from 14, offering the opportunity to use this
system directly for titration of the DMDO-solution; no
DMDO is wasted by titration with triphenylphosphine
[34]. The allylic alcohols 17 and 18 were silylated in
CH2Cl2-solution with triisopropylsilyl triflate (TIP-
SOTf) in the presence of 2,6-lutidine under standard
conditions [37] (Scheme 3).
dence the per-silyl protected glycals were expected to
give clean lithiation under the standard conditions
[16a]. From earlier work in our laboratory [16d], we
knew that side reactions in the isopropylidene series
became serious when prolonged metalation times were
applied. Restricting the reaction time to below 30 min,
the glucal derivative 27 was obtained in good yield
(vide infra). We now studied whether configurational
changes affect the stability of the glycals under the
metalation conditions (Scheme 4).
The per-silylated stannanes were obtained in good
yields; varying amounts of starting material, however,
indicated incomplete deprotonation. This may be due
to the fact that these substances are viscous, glassy oils
which resist sufficient drying even at 60–80°C in high
vacuum for 30 min prior to use. The yields did not
improve significantly upon prolonged deprotonation
which supports the idea that deprotonation is fast at
0°C [17]. The isopropylidene-protected glycals may be
divided in two classes: The derivatives with gluco- and
allo-configuration represent a trans-decaline system
while the galacto- and gulo- compounds contain a more
strained cis-decaline system. The galacto-glycal 10 with
the neighbouring siloxy group cis to the dioxane ring
represents the most strained compound in this series
which clearly affects the metalation as demonstrated by
the contrasting low yield for the stannyl galactal 28.
Even under carefully adjusted conditions ring-opening
3. Metalation
The appropriate protection of the glycals was ex-
ploited in their metalation. Considering literature prece-

176
C. Ja¨kel, K.H. Do¨tz / Journal of Organometallic Chemistry 624 (2001) 172–185
Scheme 4. Lithiation/stannylation sequence to glycals 23–30. Reaction conditions: (a) 1) 3.5 eq. tert.-BuLi, THF, −78°C, then 0°C, 20 min; 2)
3.5 eq. Bu3SnCl, THF, −78°C, 20 min; 3) H2O (excess), −78°C.
Scheme 5. Competing H-6 abstraction from the bicyclic galactal derivative 10.
occurred resulting from a fragmentation initiated by
deprotonation from C-6 to give the acyclic aldehyde 32
as the major product (Scheme 5). The stannyl glucal 27
and the stannyl allal 29 are obtained in good yields
whereas strictly controlled conditions were required for
gulal 30 to provide good yields.
or even protecting the methylene hydrogen atoms by an
increase of the steric bulk of the protective group. The
stannylated glycals described above are fairly stable
compounds which can be stored in the refrigerator for
months without decomposition which underlines their
advantage as storable anion equivalents.
Thus, the use of the isopropylidene protective group
is an excellent alternative to the bulky silyl substituents
when a 4,5-trans-relationship of the glycal results in the
formation of a trans-decaline system. The efficiency of
the protective group in the cis-decaline system is less
straightforward. Especially the galacto-configuration
results in considerable steric strain of the protected
compound causing a facile fragmentation of the bicyclic
system under the reaction conditions. Further progress
in the use of ketals as base-stable protective groups may
overcome these problems by either decreasing the strain
4. Conformational analysis
Stannyl glycals have been applied to the synthesis of
C-2 functionalized carbene complexes [38,39]. This
strategy relied on the intermediacy of carbene complex
anions [40] which allowed a stereoselective addition of
electrophiles at C-2 [16d,41]. In order to elucidate and
predict the stereochemical outcome of these reactions
we focused on a conformational study of the glycal
precursors.

C. Ja¨kel, K.H. Do¨tz / Journal of Organometallic Chemistry 624 (2001) 172–185
177
Scheme 6. 4H5- and 5H4-conformations of glycals.
In general two half-chair conformations, 4H5 and
stronger than for tri-O-acetyl-
D
-glucal [42b,43a]. For
5H4, are favoured for glycals [42]. The conformation
with an axial substituent at C-3 may be unfavourable
for steric reasons, but is strongly preferred due to the
vinylogous anomeric effect (VAE) [43]. For this reason
allals and gulals are expected to adopt predominantly a
the gulal derivatives 19 and 26 the NMR data establish
4
the H5 conformation as the only detectable conformer
at temperatures down to 223 K allowing the axial
oxygen substituent at C-3 to interact with the enol ether
p-bond (VAE). The galactals and allals show a dynamic
behaviour at room temperature suggesting an equi-
librium of the competing conformations. At low tem-
peratures pairs of two conformers could be detected as
separate compounds by NMR spectroscopy. In com-
parison, at 223 K both galactal 4 and the stannylated
galactal 24 appear as a ꢀ1:1 mixture of conformers
displaying the competing effects of the VAE and the
1,3-diaxial-like interactions to a comparable extent. A
similar situation was found for allal 20 and its stanny-
lated congener 25. As estimated from the analysis of the
J2,3-coupling constants the two conformers appear at
203 K as a ca. 10:1 (20) and ca. 5:1 (25) mixture in
favour of the 4H5-conformers. This small effect of
substitution at C-1 may be correlated with a minor
steric interaction of the bulky stannyl group with the
5
4H5-conformation. For galactals and glucals the H4-
conformer should be preferred if this stereoelectronic
effect overrides the 1,3-diaxial-like interactions [42b]. If
the glycal is fixed in a bicyclic system, the conformation
is locked and should be mainly determined by the
bicyclic system itself (Scheme 6).
NMR-spectroscopy is the method of choice to ad-
dress the conformational aspects of glycals in solution,
and it has been widely applied in analogous studies [44].
Two coupling constants, J2,3 and J2,4, are most diagnos-
tic. The vinyl–allyl coupling J2,3 depends on the torsion
angle between the olefinic plane and the allylic hydro-
gen and is smallest when the angle is 90°. For this
reason small J2,3 coupling constants are indicative for a
4H5-conformation in the glucal and galactal series as
4
5
axial-like TIPS-group at C-3. The preference of the H5
well as for a H4-conformation in the allal and gulal
conformation in the allal series in comparison with the
galactal derivatives may be attributed to the inversion
of stereochemistry at C-3 (Table 2).
In summary, the VAE seems to be the major dictat-
ing principle in the series of the monocyclic per-sily-
series. A long range coupling constant J2,4 is detectable
when H-4 is equatorial. This is true for gluco- and
allo-derivatives in the 5H4-conformation whereas the
galacto- and gulo-analogues require a 4H5-conforma-
5
tion. In addition, glucals and galactals in a H4-confor-
mation should reveil small J3,5 couplings due to the
H-3, H-5 equatorial-equatorial relationship; glucals and
allals in the 4H5-conformation are expected to give large
J4,5 coupling constants resulting from the axial–axial
setting of these hydrogen atoms [43a]. The important
coupling constants for the bicyclic glycals 9, 10, 21, 22
and 27–30 are summarized in Table 1. All isoprop-
ylidene protected glycals exhibit a 4H5-conformation
demonstrating the dominant influence of the cyclic
protective group on the conformation.
Table 1
Diagnostic coupling constants of bicylic glycals 9, 10, 21, 22 and
27–30
Compound
J2,3
J2,4
J4,5
Conformation
a
a
9
22
21
10
27
29
30
28
1.9
5.8
5.1
1.8
2.0
5.5
5.1
1.5
10.4
10.4
1.6
4H5
4H5
4H5
4H5
4H5
4H5
4H5
4H5
1.6
1.5
1.2
a
10.4
10.5
1.5
a
A different situation was found for the monocyclic
per-silylated glycals. The spectroscopic data of the tris-
1.6
1.5
1.5
5
TIPS-protected glucals 2 and 23 clearly indicate a H4-
conformation preferring the ‘all-axial’-orientation even
a Not observed.

178
C. Ja¨kel, K.H. Do¨tz / Journal of Organometallic Chemistry 624 (2001) 172–185
Table 2
matography was carried out on silica gel (Merck 60
(0.063–0.200)). All 1H- and 13C-NMR-spectra were
recorded on a Bruker DRX-500 or AM-400 spectrome-
ter. Spectra were recorded at 298 K unless otherwise
stated. Chemical shifts refer to those of residual solvent
Diagnostic coupling constants and estimated conformations of the
per-silylated glycals 2, 4, 19, 20 and 23–26
Compound J2,3
J2,4 J3,5 J4,5 Conformation
Ratio
2
4
5.2
4.2
1.8 2.0 1.8
5H4
signals based on lMe Si=0.00 ppm. Coupling constants
4
b
a
a
a
a
1.3 b 4H5/5H4
8.2 d 4H5/5H4
ꢀ1:1 e
are indicated in Hertz. Electron impact mass spectra
were recorded on a Kratos MS 50 spectrometer; FAB
mass spectra were recorded on a Kratos Concept 1H
spectrometer. Elemental analyses were obtained from a
Heraeus CHN–O-Rapid.
a
20
19
23
24
25
26
4.9 d
5.3
ꢀ10:1 f
a
2.0
4H5
5.1
1.6 2.0 2.0
5H4
a
a
a
a
3.4 c
4.2 b
5.1
3.4 c 4H5/5H4
7.3 b 4H5/5H4
ꢀ1:1 e
ꢀ5:1 f
a
a
2.0
4H5
6.2. 1,5-Anhydro-3,4-di-O-(tert-butyl-dimethylsilyl)-
a Not observed.
b Recorded at 363 K in toluene-d8.
c Recorded at 343 K in toluene-d8.
d Recorded at 333 K in toluene-d8.
e Recorded at 223 K in toluene-d8.
f Recorded at 203 K in CD2Cl2.
6-O-triisopropylsilyl-2-deoxy- -lyxo-hex-1-enitol (4)
D
Imidazol (2.45 g, 36 mmol) and TBSCl (3.62 g, 24
mmol) were added sequentially to a solution of 2.42 g
(8.0 mmol) 1,5-anhydro-6-O-triisopropylsilyl-2-deoxy-
D
-lyxo-hex-1-enitol (3) in 25 ml DMF. The reaction
lated glycals irrespective of the steric bulk. C-1 substitu-
tion of glycals by the bulky tri(n-butyl)stannyl group
has no significant influence [45] on the conformation of
the glycals, in all cases they exhibit conformational
properties comparable to their ‘H-counterparts’.
mixture was stirred at 60°C for 24 h. After recooling to
room temperature (r.t.) the solution was diluted with
100 ml water and 100 ml of Et2O. The organic layer
was separated, the aqueous phase was extracted three
times with 30 ml portions of Et2O. The combined
organic fractions were washed five times with 20 ml
portions of water, dried over MgSO4 and evaporated to
dryness. Column chromatography of the residue (SiO2,
CH2Cl2/petroleum ether: 1:4) afforded 2.63 g (4.95
mmol, 62%) of a colourless oil. Rf=0.52 (CH2Cl2/
petroleum ether: 1:4). 1H-NMR (500 MHz, 363 K,
toluene-d8): l=6.31 (H-1, dd, J=6.2, 1.0, 1H), 4.75
(H-2, dd, J=6.2, 4.2, 1H), 4.39 (H-6, dd, J=10.5, 7.1,
1H), 4.34 (H-4, dd, J=3.7, 1.3, 1H), 4.32 (H-5, ddd,
J=7.1, 3.5, 1.3, 1H), 4.28 (H-6%, dd, J=10.5, 3.5, 1H),
5. Conclusion
In conclusion, we demonstrated that the direct meta-
lation approach might be an effective transformation
even in the case of highly functionalized enol ethers (i.e.
glycals). The choice of the protective groups is crucial
and for the protection of the sensitive primary alcohol
functionality, we have introduced the isopropylidene
functionality as a new inexpensive protective group,
orthogonal to silyl ethers. Its ‘stability’ depends on the
configuration of the glycal; while the allo- and gluco-
configuration gives excellent results, the more strained
bicyclic system resulting from the galacto- or gulo-
configuration deserves further improvements. Protocols
for the per-silylation of each configuration have been
worked out which allow an efficient subsequent metala-
tion as well. The monocyclic allals and galactals reveil
an equilibrium consisting of two conformers. No sig-
nificant influence of the stannyl substituent at C-1 on
the distribution of the conformers was observed at low
temperatures.
1
4.24 (H-3, dd, J=4.2, 3.7, 1H); H-NMR (500 MHz,
223 K, toluene-d8): l=6.38 (H-1, d, J=5.9, 1H), 4.75
(H-2(1), dd, J=5.9, 5.9, 0.6H), 4.69 (H-6(1), dd, J=
11.5, 9.1, 0.7H), 4.64 (H-2(2), d, J=6.1, ꢀ0.6H), 4.59
(H-5(1), dd, J= ꢀ9.0, ꢀ5.4, ꢀ0.6H), 4.39 (H-6%(1),
d, J=11.5, ꢀ0.7H), 4.19 (H-3(2), br, 0.7H), 4.13–4.09
(H-4(1), H-4(2), m, 1.4H), 3.83 (H-3(1), dd, J= ꢀ5,
ꢀ5, ꢀ0.7H). 13C-NMR (125 MHz, 343 K, C6D6):
l=143.5 (C-1), 102.8 (C-2), 80.4, 69.5, 66.2, 62.1 (C-3,
C-4, C-5, C-6), 26.2 (-TBS), 18.3, 12.7 (–TIPS), −3.9,
−4.3, −4.5, −4.7 (–TBS). MS (EI): m/z=515.2
[M+−CH3], 487.3 [M+−C3H7], 473.3 [M+−CH3−
C3H7]. HR-MS Calc. for C24H51O4Si3 [M+−C3H7]
487.3095. Found 487.3085. Anal. Calc. for C27H58O4Si3:
C, 61.07; H, 11.01. Found C, 60.64; H, 11.00%.
6. Experimental
6.3. Phenyl 1-thio-2,3:4,6-di-O-isopropylidene-i-
6.1. General
D
-glucopyranoside (7)
All transformations were performed under argon us-
ing degassed solvents dried by standard procedures. All
reagents were used as supplied commercially; chro-
LiOH (12.7 mg, 0.53 mmol) was added to a solution
of 4.47 g (10.15 mmol) phenyl 1-thio-2,3,4,6-tetra-O-
acetyl-b- -glucopyranoside in 100 ml MeOH. After 1 h
D

C. Ja¨kel, K.H. Do¨tz / Journal of Organometallic Chemistry 624 (2001) 172–185
179
stirring at r.t. the reaction mixture was neutralized by
adding 28.8 mg (0.53 mmol) solid NH4Cl, the solvent
was removed in vacuo and the residue was distilled
three times azeotropically with 20 ml portions of tolu-
ene under reduced pressure. DMF (40 ml) was added,
and the resulting solution was treated with 0.2 g (0.81
mmol) camphorsulfonic acid (CSA). 2-Methoxypropene
(4.5 ml, 45 mmol) was added at r.t. over a period of 30
min. After stirring for additional 30 min the mixture
was diluted with 50 ml saturated aqueous sodium bicar-
bonate and extracted four times with 50 ml portions of
Et2O. The combined organic fractions were washed five
times with 30 ml portions of water, dried over MgSO4
and evaporated to dryness. Column chromatography of
the residue (SiO2, ethyl acetate/cyclohexane: 3:7; 5‰
NEt3) afforded 3.33 g (9.45 mmol, 93%) of a white
solid. Rf=0.57 (ethyl acetate/cyclohexane: 3:7). 1H-
NMR (500 MHz, C6D6): l=7.69–7.65 (Ar-H, m, 2H),
7.08–6.98 (Ar-H, m, 3H), 4.64 (H-1, d, J=9.6, 1H),
3.87 (H-6e, dd, J=10.6, 5.1, 1H), 3.74 (H-4, dd, J=
9.3, 8.9, 1H), 3.68 (H-6a, dd, J=10.6, 10.4, 1H), 3.62
(H-3, dd, J=8.6, 9.3, 1H), 3.42 (H-2, dd, J=9.6, 8.6,
1H), 3.04 (H-5, ddd, J=10.4, 8.9, 5.1, 1H), 1.42 (–
CH3, s, 3H), 1.39 (–CH3, s, 3H), 1.36 (–CH3, s, 3H),
1.10 (–CH3, s, 3H). 13C-NMR (125 MHz, C6D6): l=
133.9, 132.3, 129.0, 128.3 (Ar-C’s), 111.0 (C(CH3)2-ox-
olane), 99.4 (C(CH3)2–dioxane), 85.5 (C-1), 79.8, 76.8,
73.3, 73.2, 62.3 (C-2, C-3, C-4, C-5, C-6), 29.2, 26.8,
26.6, 18.9 (C(CH3)2). MS (EI): m/z=352.2 [M+], 337.2
[M+−CH3]. HR-MS Calc. for C18H24O5S [M+]
352.1344. Found 352.1338. Anal. Calc. for C18H24O5S:
C, 61.34; H, 6.86; S, 9.10. Found C, 61.27; H, 7.02; S,
9.22%.
85.6 (C-1), 80.1, 71.1, 70.0, 66.7, 63.0 (C-2, C-3, C-4,
C-5, C-6), 29.3, 27.0, 26.6, 18.6 (C(CH3)2). MS (EI):
m/z=352.2 [M+], 337.2 [M+−CH3]. HR-MS Calc.
for C18H24O5S [M+] 352.1344. Found 352.1352. Anal.
Calc. for C18H24O5S: C, 61.34; H, 6.86; S, 9.10. Found
C, 60.93; H, 7.07; S, 9.13%.
6.5. 1,5-Anhydro-4,6-O-isopropylidene-3-O-
triisopropylsilyl-2-deoxy- -arabino-hex-1-enitol (9)
D
Graphite (2.71 g, 225 mmol) was placed on the
bottom of a long Schlenk-flask and was stirred in vacuo
at 150°C for 30 min. After setting a positive pressure of
argon on the flask 1.10 g (28.2 mmol) potassium was
added in one portion at 150°C and stirring was contin-
ued until the material became homogeneous and
bronze-coloured (ca. 45 min). The resulting C8K was
suspended in 60 ml THF at −40°C and 3.10 g (8.8
mmol) phenyl 1-thio-2,3:4,6-di-O-isopropylidene-b-D-
glucopyranoside in 90 ml THF were added at this
temperature over a period of 1 h. After additional 30
min the reaction mixture was warmed to −20°C and
4.2 ml (19.4 mmol) triisopropylsilyl chloride (TIPSCl)
were slowly added. The suspension was allowed to
reach r.t. within 1 h and filtered over a plug of silica
gel. The resulting solution was concentrated in vacuo
and the residue was purified by column chromatogra-
phy (SiO2, ethyl acetate/cyclohexane: 1:25; 1‰ NEt3) to
afford 1.64g (4.79 mmol, 54%) of a colourless oil.
Rf=0.36 (ethyl acetate/cyclohexane: 1:25). 1H-NMR
(400 MHz, CDCl3): l=6.21 (H-1, dd, J=6.2, 1.6, 1H),
4.63 (H-2, dd, J=6.2, 1.6, 1H), 4.38 (H-3, ddd, J=7.2,
1.9, 1.6, 1H), 3.88 (H-6e, dd, J=10.7, 5.6, 1H), 3.78
(H-4, dd, J=10.4, 7.2, 1H), 3.76 (H-6a, dd, J=10.7,
10.2, 1H), 3.66 (H-5, ddd, J=10.4, 10.2, 5.6, 1H), 1.46
(–CH3, s, 3H), 1.35 (–CH3, s, 3H), 1.07–0.99 (–TIPS,
m, 21H). 13C-NMR (125 MHz, CDCl3): l=143.1 (C-
1), 105.7 (C-2), 99.5 (C(CH3)2), 73.2, 69.7, 67.7, 61.8
(C-3, C-4, C-5, C-6), 28.9, 18.9 (C(CH3)2), 17.9, 12.2
(TIPS). MS (EI): m/z=327.2 [M+−CH3], 299.2 [M+
−C3H7], 241.1 [M+−C3H7−C3H6O]. HR-MS Calc.
for C17H31O4Si [M+−CH3] 327.1992. Found 327.1984.
6.4. Phenyl 1-thio-2,3:4,6-di-O-isopropylidene-i-
D-
galactopyranoside (8)
Starting from 16.4 g (37.2 mmol) phenyl 1-thio-
2,3,4,6-tetra-O-acetyl-i- -galactopyranoside, 50 mg
D
(2.1 mmol) LiOH, 200 ml MeOH, 112.3 mg (2.1 mmol)
NH4Cl, 0.72 g (3.0 mmol) CSA, 16.3 ml (167 mmol)
2-methoxypropene and 140 ml DMF a crude oil was
obtained following the procedure described above.
Chromatographic purification (SiO2, ethyl acetate/
petroleum ether: 1:1; 5‰ NEt3) afforded 12.24 g (34.7
mmol, 93%) of a white solid. Rf=0.66 (ethyl acetate/
6.6. 1,5-Anhydro-4,6-O-isopropylidene-3-O-
triisopropylsilyl-2-deoxy- -lyxo-hex-1-enitol (10)
D
1
petroleum ether: 1:1). H-NMR (500 MHz, C6D6): l=
Starting from 7.22 g (20.49 mmol) phenyl 1-thio-
2,3:4,6-di-O-isopropylidene-b- -galactopyranoside,
7.87–7.83 (Ar-H, m, 2H), 7.13–7.02 ( Ar-H, m, 3H),
4.68 (H–1, d, J=9.4, 1H), 4.19 (H-2, dd, J=9.4, 9.4,
1H), 3.91 (H-4, dd, J=2.7, 1.0, 1H), 3.86 (H-6, dd,
J=12.7, 1.6, 1H), 3.52 (H-6%, dd, J=12.7, 2.3, 1H),
3.27 (H-3, dd, J=9.4, 2.7, 1H), 2.54 (H-5, ddd, J=2.3,
1.6, 1.0, 1H), 1.45 (–CH3, s, 3H), 1.39 (–CH3, s, 3H),
1.33 (–CH3, s, 3H), 1.12 (–CH3, s, 3H). 13C-NMR (125
MHz, C6D6): l=134.3, 132.7, 128.8, 128.1 (Ar-C’s),
110.2 (C(CH3)2–oxolane), 98.2 (C(CH3)2–dioxane),
D
6.10 g (508.2 mmol) graphite, 2.51 g (63.5 mmol)
potassium and 9.3 ml (43.0 mmol) TIPSCl a crude oil
was obtained following the procedure described above.
Chromatographic purification (SiO2, ethyl acetate/
CH2Cl2: 1:40; 2‰ NEt3) afforded 5.43 g (15.85 mmol,
77%) of a colourless oil. Rf=0.42 (ethyl acetate/
1
CH2Cl2: 1:40). H-NMR (500 MHz, CDCl3): l=6.35
(H-1, dd, J=6.4, 2.1, 1H), 4.72 (H-2, ddd, J=6.4, 1.8,

180
C. Ja¨kel, K.H. Do¨tz / Journal of Organometallic Chemistry 624 (2001) 172–185
1.5, 1H), 4.68 (H-3, ddd, J=4.6, 2.1, 1.8, 1H), 4.17
(H-4, ddd, J=4.6, 1.5, 1.2, 1H), 4.07 (H-6, dd, J=
12.8, 1.6, 1H), 4.00 (H-6%, dd, J=12.8, 2.0, 1H), 3.73
(H-5, ddd, J=2.0, 1.6, 1.2, 1H), 1.48 (–CH3, s, 3H),
1.47 (–CH3, s, 3H), 1.09–1.01 (–TIPS, m, 21H). 13C-
NMR (125 MHz, CDCl3): l=143.4 (C-1), 102.1 (C-2),
99.0 (C(CH3)2), 68.1, 66.0, 64.2, 63.2 (C-3, C-4, C-5,
C-6), 29.5, 18.4 (C(CH3)2), 17.9, 12.3 (TIPS). MS (EI):
m/z=327.3 [M+−CH3], 299.3 [M+−C3H7], 241.2
[M+−C3H7−C3H6O]. HR-MS Calc. for C17H31O4Si
[M+−CH3] 327.1991. Found 327.1991.
NH4Cl, 0.16 g (0.7 mmol) CSA, 2.5 ml (25.8 mmol)
2-methoxypropene and 50 ml DMF a crude oil was
obtained following the procedure described above.
Chromatographic purification (SiO2, ethyl acetate/cy-
clohexane: 1:6; 1% NEt3) afforded 2.26 g (8.12 mmol,
94%) of a colourless oil. Rf=0.33 (ethyl acetate/cyclo-
1
hexane: 1:6). H-NMR (400 MHz, CDCl3): l=7.55–
7.45 (Ar-H, m, 2H), 7.35–7.10 (Ar-H, m, 3H), 6.21
(H-2, ddd, J=9.8, 3.6, 0.7, 1H), 5.99 (H-3, ddd, J=
9.8, 5.4, 1.7, 1H), 5.96 (H-1, dd, J=3.6, 1.7, 1H), 4.26
(H-6, dd, J=13.0, 3.4, 1H), 4.19 (H-4, dd, J=5.4, 2.3,
1H), 4.15 (H-5, ddd, J=3.5, 2.3, 2.1, 1H), 3.96 (H-6%,
dd, J=13.0, 2.1, 1H), 1.51 (–CH3, s, 3H), 1.45 (–CH3,
s, 3H). 13C-NMR (100 MHz, CDCl3): l=135.5, 130.8,
130.7, 128.9, 127.1, 125.7 (Ar-C, C-2, C-3), 98.9
(C(CH3)2), 83.7 (C-1), 62.7 (C-6), 62.7, 60.9 (C-4, C-5),
28.8 (–CH3), 19.2 (–CH3). MS (EI): m/z=278.1 [M+],
263.1 [M+−CH3]. HR-MS Calc. for C15H18O3S [M+]
278.0976. Found 278.0971. Anal. Calc. for C15H18O3S:
C, 64.72; H, 6.52; S, 11.52. Found C, 64.78; H, 6.42; S
11.86%.
6.7. Phenyl 1-thio-4,6-O-isopropylidene-h-
D-erythro-
hex-2-enopyranoside (13)
LiOH (35.9 mg, 1.50 mmol) was added to a solution
of 9.67 g (30.0 mmol) phenyl 1-thio-4,6-di-O-acetyl-a-
D
-erythro-hex-2-enopyranoside in 100 ml MeOH. After
1 h stirring at r.t. the reaction mixture was neutralized
by adding 80.3 mg (1.50 mmol) solid NH4Cl, the sol-
vent was removed in vacuo and the residue was distilled
three times azeotropically with 20 ml portions of tolu-
ene under reduced pressure. DMF (150 ml) was added
and the resulting solution was treated with 0.56 g (2.4
mmol) CSA. 2-Methoxypropene (8.6 ml, 90 mmol) was
added at r.t. over a period of 30 min. After stirring for
additional 30 min the mixture was diluted with 50 ml
saturated aqueous sodium bicarbonate and extracted
four times with 50 ml portions of CH2Cl2. The com-
bined organic fractions were washed five times with 30
ml portions of water, dried over MgSO4 and evapo-
rated to dryness. Column chromatography of the
residue (SiO2, ethyl acetate/cyclohexane: 1:5; 5‰ NEt3)
afforded 7.85 g (28.2 mmol, 94%) of a white solid.
Rf=0.56 (ethyl acetate/cyclohexane: 1:5). 1H-NMR
(500 MHz, CDCl3): l=7.55–7.50 (Ar-H, m, 2H),
7.36–7.25 (Ar-H, m, 3H), 5.99 (H-2, dd, J=10.1, 4.4,
1H), 5.92 (H-3, ddd, J=10.1, 2.4, 2.4, 1H), 5.78 (H-1,
dd, J=4.4, 2.4, 1H), 4.34 (H-4, dd, J=8.9, 2.4, 1H),
4.02 (H-5, ddd, J=10.5, 8.9, 4.9, 1H), 3.96 (H-6e, dd,
J=10.5, 4.9, 1H), 3.85 (H-6a, dd, J=10.5, 10.5, 1H),
1.56 (–CH3, s, 3H), 1.49 (–CH3, s, 3H). 13C-NMR (125
MHz, CDCl3): l=135.3, 131.4, 129.9, 128.9, 127.4,
126.9 (Ar-C’s, C-2, C-3), 99.9 (C(CH3)2), 84.5 (C-1),
67.4, 65.5 (C-4, C-5), 62.9 (C-6), 29.2 (–CH3), 19.0
(CH3). MS (EI): m/z=278.1 [M+], 263.1 [M+−CH3].
HR-MS Calc. for C15H18O3S [M+] 278.0976. Found
278.0969. Anal. Calc. for C15H18O3S: C, 64.72; H, 6.52;
S, 11.52. Found C, 64.69; H, 6.71; S, 11.13%.
6.9. 1,5-Anhydro-3,6-di-O-acetyl-2-deoxy-D-ribo-hex-
1-enitol (16)
To a solution of 0.32 g (1.00 mmol) phenyl 1-thio-
4,6-di-O-acetyl-a- -erythro-hex-2-enopyranoside in 10
D
ml CH2Cl2 at −78°C were added 10 ml of 0.1 M
solution of dimethyldioxirane (DMDO) in acetone [34].
After one hour the solvent was removed in vacuo at
0°C and the residue was distilled two times azeotropi-
cally with 10 ml portions of toluene under reduced
pressure. Et2O (40 ml) and 0.54 ml (5.0 mmol) Et2NH
were added. The reaction mixture was stirred at r.t.
overnight and was then concentrated under reduced
pressure. The residue was purified by column chro-
matography (SiO2, ethyl acetate/cyclohexane: 1:1, 1%
NEt3) to afford 0.22 g (0.95 mmol, 95%) of a colourless
oil as an inseparable 1:0.15:0.1 mixture of regioisomeric
1
diacetates (as judged by H-NMR analysis). Rf=0.29
(ethyl acetate/cyclohexane: 1:1). 1,5-Anhydro-3,6-di-O-
acetyl-2-deoxy-
D
-ribo-hex-1-enitol:
1H-NMR
(500
MHz, C6D6): d=6.19 (H-1, d, J=5.9, 1H), 5.25 (H-3,
dd, J=5.9, 4.1, 1H), 4.80 (H-2, dd, J=5.9, 5.9, 1H),
4.50 (H-6, dd, J=12.2, 2.2, 1H), 4.38 (H-6%, dd, J=
12.2, 4.9, 1H), 3.99 (H-5, ddd, J=10.7, 4.9, 2.2, 1H),
3.71 (H-4, ddd, J=10.7, 6.0, 4.1, 1H), 2.28 (–OH, d,
J=6.0, 1H), 1.70 (–CH3, s, 3H), 1.67 (–CH3, s, 3H).
1,5-Anhydro-4,6-di-O-acetyl-2-deoxy-D-ribo-hex-1-eni-
tol: l=6.16 (H-1, d, J=5.8, 0.14H), 4.68 (H-2, dd,
J=5.8, 5.8, 0.15H), 4.42 (H-6, dd, J=12.2, 4.27,
6.8. Phenyl 1-thio-4,6-O-isopropylidene-h-
D-threo-
hex-2-enopyranoside (14)
0.16H). 1,5-Anhydro-3,4-di-O-acetyl-2-deoxy-D-ribo-
hex-1-enitol: l=6.12 (H-1, dd, J=6.1, 1.3, 0.10H),
4.65 (H-2, dd, J=6.1, 3.0, 0.10H), 3.88 (H-4, ddd,
J=8.6, 5.8, 2.5, 0.11H), 2.28 (–OH, d, J=5.8, 0.08H).
13C-NMR (125 MHz, C6D6): l=170.7, 170.6 (acetyl-
Starting from 2.77 g (8.6 mmol) phenyl 1-thio-4,6-di-
O-acetyl-a- -threo-hex-2-enopyranoside, 10.9 mg (0.45
mmol) LiOH, 100 ml MeOH, 24.4 mg (0.45 mmol)
D

C. Ja¨kel, K.H. Do¨tz / Journal of Organometallic Chemistry 624 (2001) 172–185
181
CO), 147.8 (C-1), 98.0 (C-2), 73.4, 66.2, 65.7 (C-3, C-4,
C-5), 63.3 (C-6), 20.6, 20.2 (acetyl-CH3). MS (FAB,
mNBA+NaOAc): m/z=253.0 [M++Na], 171.0 [M+
−C2H3O2]. Anal. Calc. for C10H14O6: C, 52.17; H, 6.13.
Found C, 51.81; H, 6.13%.
isopropylidene-a-D-threo-hex-2-enopyranoside, 120 ml
CH2Cl2, 120 ml of a 0.1 M solution of DMDO in acetone,
250 ml Et2O and 6.6 ml (60.7 mmol) Et2NH a crude oil
was obtained following the procedure described above.
Chromatographic purification (SiO2, ethyl acetate/cyclo-
hexane: 3:1; 1% NEt3) afforded 2.00 g (10.74 mmol, 88%)
of a colourless oil. Rf=0.49 (ethyl acetate/cyclohexane:
3:1). 1H-NMR (500 MHz, C6D6): l=6.45 (H-1, dd,
J=6.3, 0.4, 1H), 4.72 (H-2, ddd, J=6.3, 4.5, 2.0, 1H),
3.91 (H-6, dd, J=12.8, 1.8, 1H), 3.86-3.82 (H-3, H-4, m,
2H), 3. (H-6%, dd, J=12.8, 1.8, 1H), 3.37 (H-5, ddd,
J=1.8, 1.8, 1.8, 1H), 1.47 (–CH3, s, 3H), 1.28 (–OH, d,
J=4.7, 1H), 1.20 (–CH3, s, 3H). 13C-NMR (125 MHz,
C6D6): l=146.5 (C-1), 99.9 (C-2), 98.4 (C(CH3)2), 68.5,
64.9, 62.5(C-3, C-4, C-5), 62.9(C-6), 29.6, 18.5(C(CH3)2).
MS (EI): m/z=186.1 [M+], 171.1 [M+−CH3]. HR-MS
Calc. for C9H14O4 [M+] 186.0892. Found 186.0893. Anal.
Calc. for C9H14O4: C, 58.05; H, 7.58. Found C, 57.96;
H, 7.54%.
6.10. 1,5-Anhydro-4,6-di-O-acetyl-2-deoxy-
D-xylo-
hex-1-enitol (15)
Starting from 0.32 g (1.00 mmol) phenyl 1-thio-4,6-di-
O-acetyl-a- -threo-hex-2-enopyranoside, 10 ml CH2Cl2,
D
10 ml of a 0.1 M solution of DMDO in acetone, 40 ml
Et2O and 0.54 ml (5.00 mmol) a crude oil was obtained
following the procedure described above. Chromato-
graphic purification (SiO2, ethyl acetate/cyclohexane: 1:1;
1% NEt3) afforded 0.21 g (0.92 mmol, 92%) of a colourless
1
oil. Rf=0.25 (ethyl acetate/cyclohexane: 1:1). H-NMR
(500 MHz, C6D6): l=6.35 (H-1, d, J=6.2, 1H), 5.07
(H-4, ddd, J=2.4, 1.6, 1.2, 1H), 4.72 (H-2, ddd, J=6.2,
5.2, 1.6, 1H), 4.38 (H-6, dd, J=12.9, 8.9, 1H), 4.32–4.27
(H-6%, H-5, m, 2H), 3.86 (H-3, ddd, J=5.0, 5.0, 2.4, 1H),
2.00 (–OH, d, J=5.0, 1H), 1.68 (–CH3, s, 3H), 1.59
(–CH3, s, 3H). 13C-NMR (125 MHz, C6D6): l=170.0,
169.9 (acetyl-CO), 146.2 (C-1), 100.9 (C-2), 70.2, 69.6,
61.4 (C-3, C-4, C-5), 62.7 (C-6), 20.2, 20.2 (acetyl-CH3).
Anal. Calc. for C10H14O6: C, 52.17; H, 6.13. Found C,
51.85; H, 6.14%.
6.13. 1,5-Anhydro-3,4,6-tri-O-triisopropylsilyl-2-
deoxy- -ribo-hex-1-enitol (20)
D
LiOH (11.3 mg, 0.47 mmol) was added to a solution
of 2.04 g (8.86 mmol) 1,5-anhydro-4,6-O-isopropylidene-
2-deoxy-D-ribo-hex-1-enitol in 50 ml MeOH. After 2 h
stirring at r.t. the reaction mixture was neutralized by
adding 25.2 mg (0.47 mmol) solid NH4Cl, the solvent was
removed in vacuo and the residue was distilled two times
azeotropically with 10 ml portions of toluene under
reduced pressure. DMF (5 ml) and 6.8 ml (58.5 mmol)
2,6-lutidine were added. To this mixture was added a
solution of 7.9 ml (29.2 mmol) TIPSOTf in 20 ml CH2Cl2
at 0°C over a period of 30 min. The reaction mixture was
allowed to reach r.t. and stirred for 60 h. Finally the
mixture was treated with additional 1.8 ml (6.7 mmol)
TIPSOTf and heated under reflux for 4.5 h. After
recooling to r.t. the mixture was diluted with 100 ml water,
the organic layer was separated and the aqueous layer was
extracted three times with 50 ml portions of CH2Cl2. The
combined organic fractions were washed with brine, dried
over MgSO4 and evaporated to dryness. Column chro-
matography of the residue (SiO2, CH2Cl2/petroleum
ether: 1:9; 5‰ NEt3) afforded 3.40 g (5.53 mmol, 62%)
of a colourless oil. Rf=0.46 (CH2Cl2/petroleum ether:
6.11. 1,5-Anhydro-4,6-O-isopropylidene-2-deoxy-
ribo-hex-1-enitol (18)
D-
Starting from 2.78 g (10.00 mmol) phenyl 1-thio-4,6-O-
isopropylidene-a- -erythro-hex-2-enopyranoside, 100 ml
D
CH2Cl2, 100 ml of a 0.1 M solution of DMDO in acetone,
200 ml Et2O and 5.4 ml (50.0 mmol) Et2NH a crude oil
was obtained following the procedure described above.
Chromatographic purification (SiO2, ethyl acetate/cyclo-
hexane: 1:1; 5‰ NEt3) afforded 1.81 g (9.72 mmol, 97%)
of a colourless oil. Rf=0.53 (ethyl acetate/cyclohexane:
1
1:1). H-NMR (500 MHz, CDCl3): l=6.22 (H-1, dd,
J=6.1, 0.6, 1H), 4.91 (H-2, dd, J=6.1, 5.8, 1H), 4.22
(H-5, ddd, J=10.7, 10.4, 5.5, 1H), 3.99 (H-3, dd, J=5.8,
3.9, 1H), 3.96 (H-6e, dd, J=10.7, 5.5, 1H), 3.71 (H-6a,
dd, J=10.7, 10.7, 1H), 3.65 (H-4, dd, J=10.4, 3.9, 1H),
2.56 (–OH, s, 1H), 1.42 (–CH3, s, 3H), 1.20 (–CH3, s,
3H). 13C-NMR (125 MHz, CDCl3): l=146.1 (C-1), 101.2
(C-2), 99.8 (C(CH3)2), 70.7, 64.7, 61.7, 60.3 (C-3, C-4, C-5,
C-6), 28.9, 19.3 (C(CH3)2). MS (EI): m/z=186.1 [M+],
171.1 [M+−CH3]. HR-MS Calc. for C9H14O4 [M+]
186.0892. Found 186.0884. Anal. Calc. for C9H14O4: C,
58.05; H, 7.58. Found C, 58.19; H, 7.52%.
1
1:9). H-NMR (500 MHz, 333K, toluene-d8): l=6.40
(H-1, d, J=6.0, 1H), 4.93 (H-2, dd, J=6.0, 4.9, 1H), 4.63
(H-3, dd, J=4.9, 3.1, 1H), 4.55 (H-5, ddd, J=8.2, 5.3,
4.2, 1H), 4.38 (H-4, dd, J=8.2, 3.1, 1H), 4.24 (H-6, dd,
J=11.0, 4.2, 1H), 4.20 (H-6%, dd, J=11.0, 5.3, 1H),
1.40–1.10 (–TIPS, m, 63H); 1H-NMR (500 MHz, 203 K,
CD2Cl2): l=6.35 (H-1(1), d, J=5.5, 1H), 6.13 (H-1(2),
d, J=6.1, 0.11H), 4.84 (H-2(1), dd, J=5.5, 5.5, 1H), 4.53
(H-2(2), d, J= ꢀ5.5, 0.09H). 13C-NMR (125 MHz, 333
K, toluene-d8): l=137.7 (C-1), 94.3 (C-2), 69.7, 62.4, 58.1
(C-3, C-4, C-5), 56.4 (C-6), 11.1–10.4, 6.5–5.2 (–TIPS).
6.12. 1,5-Anhydro-4,6-O-isopropylidene-2-deoxy-
xylo-hex-1-enitol (17)
D-
Starting from 3.38 g (12.14 mmol) phenyl 1-thio-4,6-O-

182
C. Ja¨kel, K.H. Do¨tz / Journal of Organometallic Chemistry 624 (2001) 172–185
MS (EI): m/z=571.5 [M+−C3H7]. HR-MS Calc. for
C30H63O4Si [M+−C3H7] 571.4034. Found 571.4039.
Anal. Calc. for C33H70O4Si3: C, 64.45; H, 11.48. Found
C, 64.47; H, 11.68%.
Column chromatography of the residue (SiO2, ethyl
acetate/cyclohexane: 1:15; 1% NEt3) afforded 3.43 g
(10.0 mmol, 87%) of a colourless oil. Rf=0.51 (ethyl
1
acetate/cyclohexane: 1:15). H-NMR (500 MHz, C6D6):
l=6.19 (H-1, d, J=6.1, 1H), 4.81 (H-2, dd, J=6.1,
5.8, 1H), 4.31 (H-5, dd, J=10.4, 10.4, 5.8, 1H), 4.12
(H-3, dd, J=5.8, 3.4, 1H), 3.98 (H-6e, dd, J=10.9, 5.8,
1H), 3.74 (H-6a, dd, J=10.9, 10.4, 1H), 3.72 (H-4, dd,
J=10.4, 3.4, 1H), 1.47 (–CH3, s, 3H), 1.24 (–CH3, s,
3H), 1.23–1.16 (–TIPS, m, 21H). 13C-NMR (125 MHz,
C6D6): l=144.7 (C-1), 103.3 (C-2), 99.4 (C(CH3)2),
71.6, 65.1, 62.0 (C-3, C-4, C-5,), 62.1 (C-6), 29.2, 19.1
(C(CH3)2), 18.3, 12.7 (–TIPS). MS (EI): m/z=327.2
[M+−CH3], 299.2 [M+−C3H7], 241.2 [M+−C3H7−
C3H6O]. HR-MS Calc. for C15H27O4Si [M+−C3H7]
299.1679. Found 299.1672. Anal. Calc. for C18H34O4Si:
C, 63.11; H, 10.00. Found C, 63.11; H, 10.22%.
6.14. 1,5-Anhydro-3,4,6-tri-O-triisopropylsilyl-2-
deoxy- -xylo-hex-1-enitol (19)
D
LiOH (8.4 mg, 0.35 mmol) was added to a solution
of 1.60 g (6.95 mmol) 1,5-anhydro-4,6-O-isopropyli-
dene-2-deoxy-D-xylo-hex-1-enitol in 50 ml MeOH. Af-
ter 2 h stirring at r.t. the reaction mixture was
neutralized by adding 18.8 mg (0.35 mmol) solid
NH4Cl, the solvent was removed in vacuo and the
residue was distilled two times azeotropically with 10
ml portions of toluene under reduced pressure. DMF (5
ml) and 5.3 ml (45.9 mmol) 2,6-lutidine were added. To
this mixture was added a solution of 6.2 ml (22.9 mmol)
TIPSOTf in 20 ml CH2Cl2 at 0°C over a period of 30
min. The reaction mixture was allowed to reach r.t. and
stirred for 60 h. Over that period additional 1.0 ml (14
mmol) TIPSOTf were added in two portions. The mix-
ture was diluted with 100 ml water, the organic layer
was separated and the aqueous layer was extracted
three times with 50 ml portions of CH2Cl2. The com-
bined organic fractions were washed with brine, dried
over MgSO4 and evaporated to dryness. Column chro-
matography of the residue (SiO2, CH2Cl2/petroleum
ether: 1:9; 5‰ NEt3) afforded 3.40 g (5.36 mmol, 77%)
of a colourless oil. Rf=0.55 (CH2Cl2/petroleum ether:
1:9). 1H-NMR (400 MHz, C6D6): l=6.50 (H-1, d,
J=6.2, 1H), 4.89 (H-2, ddd, J=6.2, 5.3, 2.0, 1H), 4.39
(H-4, dd, J=2.6, 2.0, 1H), 4.34 (H-6, dd, J=9.2, 3.5,
1H), 4.30 (H-6%, dd, J=9.2, 8.3, 1H), 4.26 (H-3, dd,
J=5.3, 2.6, 1H), 4.14 (H-5, dd, J=8.3, 3.5, 1H),
1.27–1.10 (–TIPS, m, 63H). 13C-NMR (100 MHz,
C6D6): l=146.2 (C-1), 100.8 (C-2), 74.2, 68.6, 65.0
(C-3, C-4, C-5), 61.7 (C-6), 18.2-17.9, 13.4–12.1 (–
TIPS). MS (EI): m/z=571.4 [M+−C3H7]. HR-MS
Calc. for C30H63O4Si [M+−C3H7] 571.4034. Found
571.4036. Anal. Calc. for C33H70O4Si3: C, 64.45; H,
11.48. Found C, 64.42; H, 11.67%.
6.16. 1,5-Anhydro-4,6-O-isopropylidene-3-O-
triisopropylsilyl-2-deoxy- -xylo-hex-1-enitol (21)
D
2,6-Lutidine (1.72 ml, 14.8 mmol) and 2.7 ml (10.1
mmol) TIPSOTf were added sequentially to a solution
of 1.25 g (6.7 mmol) 1,5-anhydro-4,6-O-isopropylidene-
2-deoxy-D-xylo-hex-1-enitol in 40 ml CH2Cl2 at 0°C.
The reaction mixture was allowed to reach r.t. and
stirred for 3 h. After dilution with 100 ml of water the
organic layer was separated and the aqueous layer was
extracted three times with 50 ml portions of CH2Cl2.
The combined organic fractions were washed with
brine, dried over MgSO4 and evaporated to dryness.
Column chromatography of the residue (SiO2, ethyl
acetate/cyclohexane: 1:15; 1% NEt3) afforded 1.52 g
(4.44 mmol, 66%) of a colourless oil. Rf=0.32 (ethyl
1
acetate/cyclohexane: 1:15). H-NMR (500 MHz, C6D6):
l=6.53 (H-1, d, J=6.3, 1H), 4.89 (H-2, ddd, J=6.3,
5.1, 1.7, 1H), 4.10 (H-3, dd, J=5.1, 2.0, 1H), 4.02 (H-4,
ddd, J=2.0, 1.6, 1.6, 1H), 3.95 (H-6, dd, J=12.7, 1.6,
1H), 3.64 (H-5, ddd, J=1.6, 1.6, 1.6, 1H), 3.60 (H-6%,
dd, J=12.7, 1.6, 1H), 1.50 (–CH3, s, 3H), 1.29 (–CH3,
s, 3H), 1.19–1.07 (–TIPS, m, 21H). 13C-NMR (125
MHz, C6D6): l=145.8 (C-1), 100.6 (C-2), 98.4
(C(CH3)2), 70.1, 65.1, 63.7 (C-3, C-4, C-5), 63.0 (C-6),
29.6, 18.5 (C(CH3)2), 18.2, 12.6 (–TIPS). MS (EI):
m/z=327.3 [M+−CH3], 299.3 [M+−C3H7], 241.2
[M+−C3H7−C3H6O]. HR-MS Calc. for C17H31O4Si
[M+−CH3] 327.1991. Found 327.1987. Anal. Calc. for
C18H34O4Si: C, 63.12; H, 10.01. Found C, 63.12; H,
10.11%.
6.15. 1,5-Anhydro-4,6-O-isopropylidene-3-O-
triisopropylsilyl-2-deoxy- -ribo-hex-1-enitol (22)
D
2,6-Lutidine (2.94 ml, 25.3 mmol) and 4.6 ml (17.2
mmol) TIPSOTf were added sequentially to a solution
of 2.14 g (11.5 mmol) 1,5-anhydro-4,6-O-isopropyli-
dene-2-deoxy-D-ribo-hex-1-enitol in 60 ml CH2Cl2 at
6.17. 1,5-Anhydro-3,4-di-O-(tert-butyl-dimethylsilyl)-
0°C. The reaction mixture was allowed to reach r.t. and
stirred for 3 h. After dilution with 100 ml water the
organic layer was separated and the aqueous layer was
extracted three times with 50 ml portions of CH2Cl2.
The combined organic fractions were washed with
brine, dried over MgSO4 and evaporated to dryness.
6-O-triisopropylsilyl-2-deoxy-1-(tri-n-butyl)stannyl-
lyxo-hex-1-enitol (24)
D-
tert-Butyllithium (10.9 ml, 17.5 mmol) (15% in hex-
anes) was added dropwise to a solution of 2.63 g (5.0
mmol) 1,5-anhydro-3,4-di-O-(tert-butyl-dimethylsilyl)-

C. Ja¨kel, K.H. Do¨tz / Journal of Organometallic Chemistry 624 (2001) 172–185
183
6-O-triisopropylsilyl-2-deoxy-
D
-lyxo-hex-1-enitol in 20
The ring-opened aldehyde 2,5-dideoxy-4,6-O-iso-
propylidene-3-O-triisopropylsilyl- -threo-hex-5-enose
L
ml THF at –78°C. The dry ice bath was removed and
stirring was continued at 0°C for 20 min. After recooling
to −78°C, 4.7 ml (17.5 mmol) tri-n-butylstannyl chlo-
ride were added dropwise and stirring was continued at
this temperature for 20 minutes. The reaction mixture
was diluted with 50 ml water, the organic layer was
separated and the aqueous phase was extracted three
times with 60 ml portions of Et2O. The combined organic
fractions were washed two times with 20 ml water, then
with brine, dried over MgSO4 and evaporated to dryness.
Column chromatography of the residue (SiO2, CH2Cl2/
petroleum ether: 1:20; 5‰ NEt3) afforded 3.50 g (4.3
mmol, 85%) of a colourless oil. Rf=0.57 (CH2Cl2/
petroleum ether: 1:20). 1H-NMR (500 MHz, 343 K,
C6D6): l=4.95 (H-2, d, J=3.4, 1H), 4.36 (H-3, dd,
J=3.4, 3.4, 1H), 4.28 (H-6, dd, J=9.5, 6.4, 1H), 4.24
(H-4, dd, J=3.4, 3.4, 1H), 4.22–4.18 (H-5, H-6%, m, 2H),
1.70–0.90 (–SnBu3, –TIPS, –TBS, m, 66H), 0.25–0.15
(32) was isolated as main product after a second chro-
matography (SiO2, Et2O/petroleum ether: 1:4) to afford
0.47 g (1.38 mmol, 52%). Rf=0.52 (Et2O/petroleum
ether: 1:4). 1H-NMR (500 MHz, CDCl3): l=9.83 (H-1,
dd, J=2.6, 2.2, 1H), 6.38 (H-6, dd, J=6.5, 1.6, 1H), 4.76
(H-5, dd, J=6.5, 1.4, 1H), 4.29 (H-4, ddd, J=4.5, 1.6,
1.4, 1H), 4.23 (H-3, ddd, J=6.0, 4.5, 4.5, 1H), 2.66 (H-2,
ddd, 16.2, 4.5, 2.6, 1H), 2.57 (H-2%, J=16.2, 6.0, 2.2, 1H),
1.43 (–CH3, s, 3H), 1.39 (–CH3, s, 3H), 1.09–1.01
(–TIPS, m, 21H). 13C-NMR (125 MHz, CDCl3): l=
201.7 (C-1), 142.3 (C-6), 100.1 (C-5), 99.5 (C(CH3)2),
71.6, 71.2 (C-3, C-4), 47.4 (C-2), 28.2, 21.6 (C(CH3)2),
18.5, 12.9 (–TIPS). MS (EI): m/z=299.2 [M+−C3H7],
241.2 [M+−2C3H7−CH3]. HR-MS Calc. for
C15H27O4Si [M+−C3H7] 299.1679. Found 299.1670.
Anal. Calc. for C18H34O4Si: C, 63.11; H, 10.00. Found
C, 63.17; H, 9.91%.
1
(–TBS, m, 12H); H-NMR (500 MHz, 223 K, toluene-
6.19. 1,5-Anhydro-3,4,6-tri-O-triisopropylsilyl-1-
d8): l=5.21 (H-2(1), d, J=5.5, 1H), 4.99 (H-2(2), s,
1.2H). 13C-NMR (125 MHz, 343 K, C6D6): l=162.8
(C-1), 114.2 (C-2), 80.7, 69.3, 67.3 (C-3, C-4, C-5), 62.9
(H-6), 29.4, 27.6, 13.7, 10.3 (–SnBu3), 26.4, –3.7, −4.2,
−4.3, −4.5 (–TBS), 18.4, 12.7 (–TIPS). MS (FAB,
mNBA): m/z=817.5 [M+], 761.4 [M+−C4H9+H],
689.4 [M+−C9H21+H]. Anal. Calc. for C39H84O4Si3Sn:
C, 57.12; H, 10.32. Found C, 57.29; H, 10.47%.
(tri-n-butyl)stannyl-2-deoxy- -ribo-hex-1-enitol (25)
D
Starting from 10.07 g (16.37 mmol) 1,5-anhydro-3,4,6-
tri-O-triisopropylsilyl-2-deoxy- -ribo-hex-1-enitol, 35.8
D
ml (57.3 mmol) tert-butyllithium (15% in hexanes) and
15.4 ml (57.3 mmol) tri-n-butylstannyl chloride a crude
oil was obtained following the procedure described
above. Chromatographic purification (SiO2, petroleum
ether; 5‰ NEt3) afforded 10.05 g (11.12 mmol, 68%) of
6.18. 1,5-Anhydro-4,6-O-isopropylidene-3-O-
triisopropylsilyl-2-deoxy-1-(tri-n-butyl)stannyl-
lyxo-hex-1-enitol (28)
Starting from 0.91 g (2.66 mmol) 1,5-anhydro-4,6-O-
isopropylidene-3-O-triisopropylsilyl-2-deoxy- -lyxo-
1
a colourless oil. Rf=0.79 (petroleum ether). H-NMR
D-
(500 MHz, 363 K, toluene-d8): l=5.08 (H-2, d, J=4.2,
1H), 4.53 (H-3, dd, J=4.2, 3.3, 1H), 4.41 (H-5, ddd,
J=7.3, 6.9, 4.8, 1H), 4.26 (H-4, dd, J=7.3, 3.3, 1H),
4.18 (H-6, dd, J=10.3, 4.8, 1H), 4.05 (H-6%, dd, J=10.3,
6.9, 1H), 1.76–0.93 (–TIPS, –SnBu3, m, 90H); 1H-NMR
(500 MHz, 233K, toluene-d8): l=5.40 (H-2(1), d, J=
5.4, 1H), 5.18 (H-2(2), s, ꢀ0.1H). 1H-NMR (500 MHz,
203K, CD2Cl2): l=4.85 (H-2(1), d, J=6.0, 1H), 4.56
(H-2(2), s, 0.2H). 13C-NMR (125 Hz, 363 K, toluene-d8):
l=159.0 (C-1), 108.1 (C-2), 73.2, 65.3, 60.8 (C-3, C-4,
C-5), 59.4 (C-6), 23.9, 22.0, 7.2, 4.8 (–SnBu3), 15.1–12.4,
8.6–7.9 (–TIPS). MS (FAB, mNBA): m/z=903.5 [M+],
861.6 [M+−C3H7+H], 847.5 [M+−C4H9+H]. Anal.
Calc. for C45H96O4Si3Sn: C, 59.78; H, 10.70. Found C,
59.78; H, 10.73%.
D
hex-1-enitol, 6.6 ml (10.6 mmol) tert-butyllithium (15%
in hexanes) and 2.9 ml (10.6 mmol) tri-n-butylstannyl
chloride a crude oil was obtained following the procedure
described above, except for the deprotonation time (10
min) and the deprotonation temperature (−10°C).
Chromatographic purification (SiO2, CH2Cl2/petroleum
ether: 1:1; 1% NEt3) afforded 0.56 g (0.88 mmol, 33%)
of a colourless oil. Rf=0.71 (CH2Cl2/petroleum ether:
1
1:1). H-NMR (500 MHz, CDCl3): l=4.67 (H-2, dd,
J=1.5, 1.5, 1H), 4.59 (H-3, dd, J=3.5, 1.5, 1H), 4.08
(H-4, ddd, J=3.5, 1.5, 1.5, 1H), 3.95 (H-6, dd, J=12.5,
1.8, 1H), 3.87 (H-6%, dd, J=12.5, 1.8, 1H), 3.63 (H-5, br,
1H), 1.44 (–CH3, s, 3H), 1.41 (–CH3, s, 3H), 1.55–0.80
(–TIPS, –SnBu3, m, 48H). 13C-NMR (125 MHz,
CDCl3): l=162.7 (C-1), 112.4 (C-2), 98.6 (C(CH3)2),
68.3, 66.3, 64.8, 63.7 (C-3, C-4, C-5), 29.4, 18.8
(C(CH3)2), 28.9, 27.2, 13.6, 9.6 (–SnBu3), 18.0, 12.4
(–TIPS). MS (EI): m/z=589.3 [M+−C3H7], 575.3
[M+−C4H9]. HR-MS Calc. for C26H51O4Si116Sn [M+
−C4H9] 571.2574. Found 571.2554. Anal. Calc. for
C30H60O4SiSn: C, 56.93; H, 9.58. Found C, 57.12; H,
9.40%.
6.20. 1,5-Anhydro-4,6-O-isopropylidene-3-O-
triisopropylsilyl-2-deoxy-1-(tri-n-butyl)stannyl-
D-
ribo-hex-1-enitol (29)
Starting from 0.74 g (2.16 mmol) 1,5-anhydro-4,6-O-
isopropylidene-3-O-triisopropylsilyl-2-deoxy- -ribo-
D
hex-1-enitol, 4.7 ml (7.6 mmol) tert-butyllithium (15% in
hexanes) and 2.0 ml (7.6 mmol) tri-n-butylstannyl
chloride a crude oil was obtained following the pro-
cedure described above. Chromatographic purification

184
C. Ja¨kel, K.H. Do¨tz / Journal of Organometallic Chemistry 624 (2001) 172–185
(SiO2, CH2Cl2/petroleum ether: 1:1; 5‰ NEt3) afforded
1.17 g (1.85 mmol, 86%) of a colourless oil. Rf=0.67
(CH2Cl2/petroleum ether: 1:1). 1H-NMR (400 MHz,
C6D6): l=5.26 (H-2, d, J=5.5, 1H), 4.42 (H-5, ddd,
J=10.5, 10.5, 5.9, 1H), 4.21 (H-3, dd, J=5.5, 3.5, 1H),
4.09 (H-6e, dd, J=11.0, 5.9, 1H), 3.94 (H-4, dd, J=
10.5, 3.5, 1H), 3.87 (H-6a, dd, J=11.0, 10.5, 1H), 1.52
(–CH3, s, 3H), 1.28 (–CH3, s, 3H), 1.75–0.95 (–TIPS,
–SnBu3, m, 48H). 13C-NMR (100 MHz, C6D6): l=
164.5 (C-1), 114.9 (C-2), 99.4 (C(CH3)2), 72.0, 65.7,
62.5 (C-3, C-4, C-5), 62.5 (C-6), 29.1, 19.2 (C(CH3)2),
29.3, 27.5, 13.9, 10.2 (–SnBu3), 18.4, 12.8 (–TIPS). MS
(EI): m/z=631.4 [M+], 589.4 [M+−C3H7], 575.4 [M+
−C4H9]. HR-MS Calc. for C27H53O4Si116Sn [M+−
C3H7] 585.2726. Found 585.2728. Anal. Calc. for
C30H60O4SiSn: C, 56.93; H, 9.58. Found C, 57.00; H,
9.54%.
1H), 3.99 (H-6, dd, J=12.5, 1.2, 1H), 3.72 (H-5, ddd,
J=1.5, 1.5, 1.2, 1H), 3.65 (H-6%, dd, J=12.5, 1.5, 1H),
1.53 (–CH3, s, 3H), 1.31 (–CH3, s, 3H), 1.75–0.95
(–TIPS, –SnBu3, m, 48H). 13C-NMR (100 MHz,
C6D6): l=165.6 (C-1), 111.7 (C-2), 98.1 (C(CH3)2),
69.9, 65.3, 63.5 (C-3, C-4, C-5), 63.4 (C-6), 29.5, 18.4
(C(CH3)2), 29.2, 27.4, 13.7, 9.8 (–SnBu3), 18.1, 12.5
(–TIPS). MS (EI): m/z=631.2 [M+], 589.2 [M+−
C3H7], 575.3 [M+−C4H9]. HR-MS Calc. for
C26H51O4Si116Sn [M+−C4H9] 571.2574. Found
571.2568. Anal. Calc. for C30H60O4SiSn: C, 56.93; H,
9.58. Found C, 57.28; H, 10.01%.
Acknowledgements
Support of this work by the Deutsche Forschungsge-
meinschaft (Graduiertenkolleg ‘Spektroskopie isolierter
und kondensierter Moleku¨le’), the Fonds der Chemis-
chen Industrie and the Ministry of Science and Re-
search (NRW) is gratefully acknowledged.
6.21. 1,5-Anhydro-3,4,6-tri-O-triisopropylsilyl-1-
(tri-n-butyl)stannyl-2-deoxy- -xylo-hex-1-enitol (26)
D
Starting from 4.06 g (6.60 mmol) 1,5-anhydro-3,4,6-
tri-O-triisopropylsilyl-2-deoxy- -xylo-hex-1-enitol, 14.4
D
References
ml (23.1 mmol) tert-butyllithium (15% in hexanes) and
6.22 ml (23.1 mmol) tri-n-butylstannyl chloride a crude
oil was obtained following the procedure described
above. Chromatographic purification (SiO2, petroleum
ether; 5‰ NEt3) afforded 4.12 g (4.55 mmol, 69%) of a
colourless oil. Rf=0.81 (petroleum ether). 1H-NMR
(400 MHz, C6D6): l=5.29 (H-2, dd, J=5.1, 2.0, 1H),
4.41 (H-4, dd, J=2.5, 2.0, 1H), 4.33 (H-6, dd, J=8.6,
4.6, 1H), 4.30 (H-6%, dd, J=8.6, 8.6, 1H), 4.24 (H-3,
dd, J=5.1, 2.5, 1H), 4.18 (H-5, dd, J=8.6, 4.6, 1H),
1.85–0.91 (–TIPS, –SnBu3, m, 100H). 13C-NMR (90
MHz,C6D6): l=166.1 (C-1), 112.2 (C-2), 74.6, 68.8,
65.1 (C-3, C-4, C-5), 62.2 (C-6), 29.2, 27.4, 13.1, 9.7
(–SnBu3), 18.3–18.0, 13.1–12.1 (–TIPS). MS (FAB,
mNBA): m/z=903.5 [M+], 861.6 [M+−C3H7+H],
847.5 [M+−C4H9+H]. Anal. Calc. for C45H96O4Si3Sn:
C, 59.70; H, 10.70. Found C, 59.91; H, 10.77%.
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6.22. 1,5-Anhydro-4,6-O-isopropylidene-3-O-
triisopropylsilyl-2-deoxy-1-(tri-n-butyl)stannyl-
D-
xylo-hex-1-enitol (30)
Starting from 1.32 g (3.85 mmol) 1,5-anhydro-4,6-O-
isopropylidene-3-O-triisopropylsilyl-2-deoxy- -xylo-
D
hex-1-enitol, 7.9 ml (13.5 mmol) tert-butyllithium (15%
in hexanes) and 3,6 ml (13.5 mmol) tri-n-butylstannyl
chloride a crude oil was obtained following the proce-
dure described above. Chromatographic purification
(SiO2, CH2Cl2/petroleum ether: 2:3; 5‰ NEt3) afforded
1.56 g (2.47 mmol, 64%) of a colourless oil. Rf=0.55
(CH2Cl2/petroleum ether: 2:3). 1H-NMR (400 MHz,
C6D6): l=5.29 (H-2, dd, J=5.1, 1.6, 1H), 4.10 (H-3,
dd, J=5.1, 2.0, 1H), 4.07 (H-4, ddd, J=2.0, 1.6, 1.5,
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