New polymer-supported organosilicon reagents

Article abstract of DOI:10.1002/ejoc.200500252

New polymer-supported organosilanes have been prepared using two different strategies. These involved the synthesis of soluble and insoluble supports through the copolymerization of styrene and monomers containing a thiophene ring. Selective metallation o

Full text of DOI:10.1002/ejoc.200500252

FULL PAPER
New Polymer-Supported Organosilicon Reagents
Anne Fauvel,[a] Hervé Deleuze,*[a] and Yannick Landais*[a]
Keywords: Polymerization / Solid-phase synthesis / Metallation / Silicon / Tamao–Fleming oxidation
New polymer-supported organosilanes have been prepared
using two different strategies. These involved the synthesis
tion. These supports can be used for solid-phase organic syn-
thesis, the product being released through a Tamao–Fleming
of soluble and insoluble supports through the copolymeriza- oxidation, which generates an additional hydroxy group dur-
tion of styrene and monomers containing a thiophene ring.
Selective metallation of the thiophene ring followed by si-
lylation allowed the introduction of various functionalized or-
ganosilanes onto the polymer with a high degree of substitu-
ing the cleavage along with the recycled support.
(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim,
Germany, 2005)
port, named “rasta silanes”, was recently developed by
Hodges et al.[6] The principal method used to introduce a
silyl group onto a preformed support involves the metalla-
tion of an aromatic nucleus. Generally, a polymer contain-
ing a styrene moiety is deprotonated using strong bases
(nBuLi/TMEDA) before the addition of the desired electro-
philic silyl reagent.[7] Various polymer-supported organosil-
icon compounds have thus been prepared by using this ap-
proach, although metallation is sometimes tedious and only
partial.
In the course of our research into the use of organosil-
icon intermediates in organic synthesis, we have developed
new organosilicon-based building blocks and studied vari-
ous functionalizations of chiral organosilanes by using the
silicon group both to control the stereochemistry of new
stereogenic centres[8] and as a masked hydroxy group.[9] We
thus planned to extend part of this chemistry to organosil-
anes (vinyl- and allylsilanes) grafted onto a polymer sup-
port, taking advantage of the polymer to access a larger
range of target molecules.
Our strategy is based on the utilization of a home-made
polystyrene-based polymer having an arylsilyl linker. The
choice of such a linker was dictated by pioneering studies
by Fleming and co-workers who showed that an arylsilyl
group can be converted into an OH group under mild oxi-
dative conditions.[10] Consequently, the arylsilyl group can
be considered a masked hydroxy group. Such a transforma-
tion is now extensively used in organic synthesis and has
found many applications in the total synthesis of natural
products.[9] We envisioned extending such an approach to
solid-phase synthesis. It was anticipated that an arylsilyl
linker would be particularly well adapted for solid-phase
synthesis, being stable to a variety of conditions but easily
removable through a mild oxidative treatment. Function-
alization of the aryl moiety should be carried out through
Introduction
Solid-phase synthesis, which now encompasses not only
peptide chemistry but also the combinatorial synthesis of a
large range of small organic molecules, has recently enjoyed
considerable interest.[1] The effect of the nature of the linker
used to graft the functionable moiety to the polymer frag-
ment has been studied in depth. The linker is particularly
important in that it must be stable to the conditions used
throughout the synthesis but has to be cleaved or removed
without the undesired transformation of the final product.
In this context, the use of silicon linkers is widespread as
they can be removed under numerous orthogonal condi-
tions.[2] Many silicon linkers are very often traceless, leaving
in the medium only silicates that are easily removed by sim-
ple aqueous treatment. Two main strategies have been de-
veloped to incorporate a silylated moiety onto a support:
either a silylated monomer is synthesized and copolymer-
ized to give the support or a polymeric support is chemi-
cally modified in order to introduce the silyl group. In the
literature, examples illustrating the direct method of intro-
duction of silicon by copolymerization are rather scarce.
Among them, one can mention the work of Nakahama and
co-workers on the synthesis of vinyl monomers bearing hy-
drosilane functions.[3] Fréchet and co-workers have also
synthesized a vinyl monomer containing a silylated group
that was then copolymerized with styrene and divinylben-
zene to give an insoluble support.[4] Polymerization by
hydrosilylation was developed by Itsuno et al. to introduce
silyl functions onto a support.[5] Lastly, a new kind of sup-
[a] University Bordeaux-I, Laboratoire de Chimie Organique et
Organométallique,
351, Cours de la Libération, 33405 Talence Cedex, France
Fax: +33-540006286
E-mail: h.deleuze@lcoo.u-bordeaux1.fr
y.landais@lcoo.u-bordeaux1.fr
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© 2005 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
DOI: 10.1002/ejoc.200500252
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New Polymer-Supported Organosilicon Reagents
FULL PAPER
metallation then silylation (i.e. I Ǟ II, Scheme 1). As men- quent elaboration of the carbon framework in II (RЈ) would
tioned above, many aryl groups can be metallated by using provide III (RЈЈ) which would then be submitted to Tamao–
strong bases but precedent in the literature has shown that Fleming oxidation,[9] releasing alcohol IV as well as the re-
such functionalizations are often tedious allowing only low covered polymer I which should thus be reusable. The re-
polymer loading.[11] We thus turned our attention to thio- lease of the organic compound from the polymer would
phene-based polymers which should be easier to function- thus be accompanied by the introduction of an additional
alize. The acidity of the thiophene C-2 proton is relatively OH group (i.e. IV). Note that oxidation of a C–Si bond to
high compared with the acidity of other aromatic protons, the corresponding C–OH bond has never been used to the
thus allowing easier metallation of thiophenes than of best of our knowledge in solid-phase synthesis as silicon
phenyl analogues.[12] Moreover, we have previously shown linkers are usually simply replaced by a proton through pro-
that a thienyldimethylsilyl group could be used as a latent todesilylation.[2] We report herein our preliminary studies
hydroxy group.[13] Note that, with this silyl group, the re- on the preparation of polymer-supported organosilane rea-
moval of the aromatic group of the arylsilyl moiety, which gents of type I and evaluate their use in the multi-step syn-
precedes the oxidation step, can be carried out under either thesis of a model alcohol.
electrophilic (protodesilylation) or nucleophilic conditions.
This point is crucial if one considers that the silicon group
Results and Discussion
will be unmasked on substrates possessing functionalities
that may be sensitive to electrophiles or nucleophiles. Two
different routes can be envisioned depending on the nature
of the target silane. A few functionalized chlorosilanes
(RЈR2SiCl) are commercially available. These can be easily
introduced after metallation of the thiophene ring, follow-
ing route A.[14] However, although this approach is straight-
forward, it is limited by the number of chlorosilanes avail-
able. Therefore, a second approach (route B) was envisaged
which should offer access to a broader range of organosil-
anes. This strategy involves the reaction of the metallated
thiophene moiety with a dichlorosilane to produce “in situ”
the corresponding chlorosilane which can then react with a
second organometallic species RЈM to produce II. Subse-
Our first polymer was prepared from the copolymeriza-
tion of styrene with vinylthiophene 3. The latter was pre-
pared in two steps following a method recently reported by
O’Doherty and co-workers[15] for the preparation of vi-
nylfuran. Addition of the Grignard derivative of (chlo-
romethyl)trimethylsilane to thiophene-2-carboxaldehyde led
to β-hydroxysilane 2 in a good and reproducible yield
(Scheme 2). β-Hydroxysilane 2 was then treated, without
further purification, with acid to provide, after Peterson eli-
mination, the desired 2-vinylthiophene[16] in a 71% purified
yield.
Scheme 2.
The soluble support based on styrene (x = 0.9) and 2-
vinylthiophene 3 (y = 0.1) was synthesized in toluene at
80 °C by radical copolymerization using AIBN as the initia-
tor. The copolymerization reactivity ratio of styrene and 2-
vinylthiophene reported in the literature is 0.35 and 3.10,
respectively, showing that 2-vinylthiophene reacts more
rapidly than styrene.[17] Therefore, the copolymers obtained
are probably not strictly statistical. However, the degree of
sulfur incorporation (mmolg–1) obtained is close to that ex-
pected, based on monomer feed composition. A reasonable
yield of the soluble thiophene-based polymer 4 was thus
obtained (Scheme 3). We also prepared an insoluble version
of the above polymer through the copolymerization of sty-
rene, divinylbenzene (DVB) and 3. Such polymers are com-
monly used as they facilitate handling and recovery of the
support. We chose to prepare gel-type beads through sus-
pension polymerization using DVB as a crosslinking agent
Scheme 1.
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A. Fauvel, H. Deleuze, Y. Landais
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(2%) and styrene as the chain dilutant (Scheme 3). In our
first attempt, an aqueous phase was used as the suspending
medium. However, whatever the stabiliser used [acacia gum
or poly(vinyl alcohol) (PVA)], we were unable to obtain be-
ads in a satisfactory yield. The high solubility of 2-vinyl-
thiophene in water was identified as a possible drawback
and, therefore, water was replaced by a perfluorous medium
such as perfluorooctane.[18] Under these conditions, beads
of 5 of a satisfactory size and shape were obtained in a
good yield.
Scheme 4.
As mentioned above, the high solubility of vinylthio-
phene 3 made the preparation of the insoluble support 5
rather troublesome. Therefore, it was envisioned that a more
lipophilic monomer such as 8,[21] possessing both a styrene-
based structure and a thiophene moiety, would facilitate the
preparation of an insoluble support with a reactivity close
to that of styrene. Monomer 8 was prepared in good yield
through the palladium-mediated Negishi coupling of thio-
phene and p-bromostyrene (Scheme 5).[22]
Scheme 3.
Having prepared the polymers, we then investigated the
functionalization step (I Ǟ II, Route A, Scheme 1). Lithi-
ation of the soluble polymer 4 was easily carried out with
nBuLi at –50 °C, followed by the addition of the desired
chlorosilanes (Scheme 4). Polymer-supported silanes 6a–c
were thus obtained in good yields after precipitation from
MeOH and showed excellent levels of substitution (50–
70%).[19] 1H NMR and elemental analyses unambiguously
indicated the incorporation of the silane moiety onto the
polymer. Note that much lower degrees of substitution
(DS),[19] ranging between 6 and 10%, were observed with
the analogous soluble polystyrene under drastic conditions
(nBuLi/TMEDA at 65 °C in cyclohexane for 4 hours). The
insoluble support was also metallated under similar condi-
tions, then silylated with tetramethyldisiloxane to give 7
with a good degree of substitution. IR experiments and ele-
mental analysis were used to prove the presence of the Si–
H bond and thus the grafting of the silane moiety onto the
polymer. As a comparison, metallation then silylation of
commercially available Amberlite XE 305 resin (styrene and
divinylbenzene resin, 2% crosslinking) using chlorodime-
thylsilane and allylchlorodimethylsilane led to degrees of
substitution of 19 and 26%, respectively.[20] This is in good
agreement with previous reports by Farrall and Fréchet[11]
who claimed a maximum degree of substitution of 23% un-
der conditions similar to those described above and using
carbon dioxide as an electrophile. To summarize, metalla-
tion of our thiophene-based polymers is, as expected, much
easier and allows a high degree of substitution under condi-
tions compatible with the resin structure.
Scheme 5.
The soluble support 9 was prepared through the copoly-
merization of styrene (x = 0.85) and 8 (y = 0.15) in toluene
at 80 °C under radical conditions using AIBN as the initia-
tor (Scheme 6). Polymer 9 was thus obtained after 3 days
in a satisfying 64% yield. The insoluble analogue 10 was
prepared, as above, through the suspension copolymeriza-
tion of styrene (x = 0.87), 8 (y = 0.11) and divinylbenzene
(z = 0.02) in an aqueous medium. This led to gel-type beads
of 10 in good yields of 45–69%.
Scheme 6.
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New Polymer-Supported Organosilicon Reagents
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Several typical features of 10 were determined such as
bead size and swelling (Tables 1 and 2).[1a] Swelling has
been measured in beads that have a diameter of 0.8–1 mm
in various solvents. The resin absorbs solvents to a certain
extent which provides information on site accessibility and
consequently on the functionalization of the resin.[23] As
shown in Table 2, swelling of 10 is reasonable in THF, ben-
zene, toluene and chlorinated solvents, but is usually lower
than that exhibited by 1% crosslinked styrene/divinylben-
zene copolymer (PS/DVB-1). However, this indicates that
our polymer should be useful with most organic solvents
and particularly in THF, in which lithiation reactions are
usually carried out, thus mimicking to a certain extent solu-
tion-phase conditions.
Table 1. Distribution of bead size of polymer 10 (see Scheme 6).
Scheme 7.
Diameter [mm]
Distribution [%]
Ͼ1
35
49
12
4
0.8–1
0.5–0.8
Ͻ0.5
sensitivity to moisture, we considered the alternative ap-
proach B (Scheme 1) which should allow a larger range of
silicon substituents. In this strategy, the sensitive chlorosi-
lane intermediate is generated in situ and is simply washed
before the addition of the second functionalized organome-
tallic reagent RЈM.[24] The chlorosilane is prepared through
the reaction of the supported lithiated thiophene with a
suitable dichlorosilane.[25] Variability is thus afforded both
by the choice of dichlorosilane R2SiCl2 and by the organo-
metallic reagents RЈM. It is important to note that this
strategy cannot be applied to soluble supports as crosslink-
ing between the macromolecular chains generally occurs
leading to gelatinous and unusable supports. Therefore, we
limited our study to insoluble support 10 in which
crosslinking should be more limited. This was first tested
by synthesizing the supported organosilane reagents 12a
and 12b (Scheme 8).
Table 2. Swelling of 10 and PS/DVB-1 in different solvents (see
Scheme 6).
Solvent
Volume of swollen resin
Volume of swollen resin,
PS/DVB-1 [mLg1]
10 [mLg1]
THF
4.8
4.8
4.6
4.2
4.2
2.8
Ͻ0.3
8.8
–
8.5
8.3
–
5.6
1.6
Benzene
Toluene
CH2Cl2
CCl4
DMF
MeOH
Support 9 was functionalized under the same conditions
as described above for the functionalization of support 4.
A slight excess of nBuLi was used and then tetramethyldis-
iloxane or allylchlorodimethylsilane were added to provide
resin-bound organosilanes 11a or 11b with a degree of sub-
stitution of 56% and 93%, respectively (Scheme 7). Metal-
lation of support 10 was carried out under the following
optimized conditions: nBuLi (4 equiv.) in THF with a
0.04  concentration at –50 °C over 2 hours. Addition of
TMEDA (4 equiv.) generally improves the degree of substi-
tution. Higher or lower temperatures led to a decrease in
DS. Similarly, lithiation over a shorter period of time led to
incomplete metallation while a longer period led to low DS.
Lithiation of insoluble resin 10 then silylation under these
optimized conditions led to 12a,b with degrees of substitu-
tion of 85 and 82%, respectively.
While these results (Schemes 4 and 7) were satisfying in
terms of the degree of substitution, it was still necessary to
extend the method to a broader class of polymer-bound
organosilanes. One limitation of approach A is the poor
availability of functionalized chlorosilanes. To increase the
diversity of supported organosilane reagents, it was thus
necessary to have in hand differently substituted chlorosi-
lanes. As these are often difficult to prepare owing to their Scheme 8.
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A. Fauvel, H. Deleuze, Y. Landais
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To estimate the degree of substitution of the support, supports, with the overall yield varying with the nature of
we made the assumption that the chlorosilane intermediate the support. The best results were obtained with the insolu-
formed does not undergo any partial in situ hydrolysis and ble support 10, with both a high degree of substitution
reacts completely with the organometallic species RMgBr achieved during the silylation process and an overall yield
or RLi. We could then observe a significant decrease in the of 39% in alcohol 17[30] (entry 4, Table 3).
degree of substitution in compounds 12a,b obtained
Table 3. Solid-support synthesis of alcohol 17 (see Scheme 9).
through route B compared with those obtained through
Entry
Support
DS of supported silane
[%][a]
Yield [%][b]
route A (Scheme 7). However, this strategy allows such a
variation of the substituents at silicon that we chose to con-
tinue our study by introducing new silylated functions onto
the insoluble support 10. Ph2SiCl2 was added after lithi-
ation of 10 with an excess of nBuLi (4 equiv.) to generate
the chlorosilane intermediate which was finally quenched
with phenylbutadienyllithium (13)[26] (2.5 equiv.) or cyclo-
pentadienyllithium (14)[27] (4 equiv.) to give, respectively,
supported dienylsilanes 12d and 12e with good degrees of
substitution. These last two examples illustrate the flexibil-
ity of route B, which allows functionalized organosilanes to
be grafted in a single pot. Washing is generally required
in order to discard excess reagents. Commercially available
Ph2SiCl2 was selected as a dichlorosilane as it often pro-
vides better yields than Me2SiCl2.
With our supported organosilanes in hand, we then
tested the validity of the approach summarized in
Scheme 1. A simple four-step sequence was studied as a test
case. This involved the introduction of a SiMe2H group
onto the support through silylation (generating silanes 6a,
7, 11a and 12a), followed by platinum-mediated hydro-
silylation[28] of safrole to give 15a–d, cleavage from the resin
to release silanol 16 and Tamao–Fleming oxidation[9,29] of
the latter to release the desired alcohol 17 (Scheme 9). The
sequence was carried out with soluble supports 4 and 9 and
insoluble supports 5 and 10. The results are summarized in
Table 3. The complete sequence was successful with the four
1
2
3
4
4
5
55
47
56
81
20
16
26
39
9
10
[a] DS calculated following ref.[19]. [b] Isolated yield.
In each case the support was recovered after desilylation
under nucleophilic conditions (TBAF, DMF). These pre-
liminary results confirm that our home-made polymer can
be used for solid-phase synthesis.
As cleavage from the resin and oxidation of the silicon
group are the key steps of the sequence, the use of sources
of fluoride other than TBAF were evaluated using com-
pound 20 as a model by estimating the yield of the arylthi-
ophene 18 recovered after desilylation (Scheme 10). Most
of the fluoride sources tested led to high yields of 18. Note
that TBAF gave similar results in THF and DMF (1.45 h
and 1.5 h at 20 °C and 83 and 91% yields, respectively) and
led to a faster reaction than CsF in DMF (20 °C).
nBu4N(SnPh3F2)[31] in THF and (Me2N)3S(Me3SiF2)
(TAS-F)[32] in DMF reacted more slowly (22 h under reflux
and 4.5 h at 20 °C, respectively) to provide 18 in 88 and
90% yields, respectively. HF/pyridine in THF led essentially
to degradation. Therefore, TBAF in DMF at 20 °C appear
to be the best conditions for the desilylation process in so-
lid-support synthesis.
Scheme 10.
As mentioned above, oxidation of the C–Si bond occurs
Scheme 9.
in two distinct steps: first, nucleophilic cleavage of the target
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New Polymer-Supported Organosilicon Reagents
Table 4. Recycling of solid supports.
FULL PAPER
Entry
Support
Supported silane (1st cycle)
Supported silane (2nd cycle)
DS [%][a]
S [mmolg–1][b]
DS [%][a]
S [mmolg–1][b]
1
2
3
4
4
5
55
47
56
81
0.9
1.1
1.4
1.2
79
22
95
67
0.6
0.9
1.4
1
9
10
[a] DS calculated following ref.[19]. [b] Sulfur content estimated through elemental analysis.
molecule from the support, then oxidation of the organosil- synthesis (SPOS). The high acidity of the thiophene ring
ane in solution. Precedent in the laboratory has shown that allows easy metallation which leads to high levels of organ-
these two steps may be carried out in a single pot under osilane-functionalized intermediates, in contrast to the low
solution-phase conditions. Unfortunately, we have been un- degree of substitution found in polystyrene-based polymers.
able to extend these conditions to the solid-phase synthesis The thiophene ring also allows cleavage of the product from
of 17. It is also important to mention that our efforts to the resin under mild nucleophilic conditions (TBAF). We
oxidize the C–Si bond under electrophilic “one-pot” condi- also report here the first application of the Tamao–Fleming
tions[10] have also failed under solid-phase conditions, while oxidation reaction to selectively cleave and subsequently ox-
they provided excellent yields of alcohol 17 and bromide 22 idize an organosilane supported on a polymeric matrix. Re-
when applied to model compound 20 (Scheme 11). This lease of the product under oxidative conditions not only
may be indicative of the difficulty of sterically hindered rea- leads to an additional hydroxy group, but also allows the
gents such as bromine to access the reactive function (here support to be recycled. Finally, we have been able to incor-
the thiophene ring for an ipso substitution).
porate functionalized organosilanes onto the polymer sup-
port using a short one-pot sequence (route B).[33] This con-
siderably extends the number of supported organosilanes
that are available, the variability of the substituents on the
silicon centre leading to further applications of this strategy
in polymer-supported organic synthesis. Functionalization
of these supports is currently underway and will be reported
in due course.
Experimental Section
Scheme 11.
General Remarks: NMR analyses were carried out with Bruker AC-
200 FT (200 MHz for proton, 50.4 MHz for carbon), Bruker AC-
Recycling of the support was also studied by submitting
the recovered polymers 4, 5, 9 and 10 to a second lithiation/ 250 FT (250 MHz for proton, 63 MHz for carbon) and Bruker
DPX-300 (300 MHz for proton, 75.5 MHz for carbon) spectrome-
silylation sequence. The results summarized in Table 4 indi-
cate that a second lithiation did occur, demonstrating that
our supports may be recycled. However, the level of incor-
poration of the silane (DS) varies from one support to an-
other. For instance, in entries 2 and 4, the degree of substi-
tution is lower on the second run. Elemental analysis of the
support after the synthesis of alcohol 17 indicates that sili-
con content in the support is very low (0.07 mmol Si per g
support), thus eliminating the hypothesis of an incomplete
1
ters using deuteriated chloroform as the solvent. The H and 13C
chemical shifts (δ) are given relative to the internal reference (TMS)
and are expressed in ppm. The coupling constants (J) are expressed
in Hertz. The following abbreviations were used: s (singlet), d
(doublet), t (triplet), q (quadruplet), dd (doublet of doublets), m
(multiplet) and br. (“broad peak”). Gas chromatography was car-
ried out with a Hewlett Packard HP 4890A instrument. Some mass
spectra (low resolution) were obtained using a Thermo Quest Fin-
nigan Trace GC-MS apparatus with electronic impact ionization
desilylation upon TBAF treatment. In contrast, partial de- (ionization potential: 70 eV). Other mass spectra (low and high res-
olution) were obtained with a Micromass autospec-Q spectrometer.
The electronic impact (ionization potential: 70 eV) and LSIMS
modes [potential of ionization: 35 keV, matrix: (3-nitrophenyl)
methanol] were used to achieve ionization. IR spectra were ob-
tained with a Perkin–Elmer Paragon 1000 FT-IR spectrometer as
a liquid film on NaCl crystal or as a powder with KBr. The wave-
lengths (ν) are expressed in cm–1. Elemental analyses were per-
formed by the Service Central d’Analyses, Vernaison, France; re-
sults are expressed in weight percent (wt.-%). The sulfur content in
the polymer is denoted as Scont and given in mmol S per g. The
silicon content in the polymer is denoted as Sicont and given in
mmol Si per g.
gradation of the insoluble supports (entries 2 and 4) is likely
as shown by the slightly lower sulfur content in the support
after the second silylation. Finally, soluble supports 4 and
9 (entries 1 and 3) exhibit a higher incorporation of silicon
after the second silylation with a slightly lower sulfur con-
tent. This surprising result is probably due to the sensitivity
of the lithiation/silylation sequence toward moisture, lead-
ing to reproducibility problems.
Conclusions
In conclusion, we have prepared a series of soluble and
1-(2-Thienyl)-2-(trimethylsilyl)ethanol (2): Magnesium turnings
insoluble supported organosilanes for solid-phase organic (2.85 g, 117.3 mmol) were placed in a dry three-necked flask
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A. Fauvel, H. Deleuze, Y. Landais
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equipped with a reflux condenser, a thermometer, an inlet for nitro-
gen and a septum. A few drops of a solution of (chloromethyl)
dimethylsilane (13.62 mL, 97.6 mmol) in diethyl ether (57 mL) were
added. The reaction was initiated by adding few drops of 1,2-dibro-
moethane and gentle heating. After (chloromethyl)dimethylsilane
in diethyl ether had been added, the mixture was refluxed for 1 h
and then cooled to 0 °C. Thiophene-2-carbaldehyde (1) (8 mL,
85.6 mmol) in diethyl ether (86 mL) was slowly added. The mixture
was stirred at 0 °C for 3 hours, then at room temperature for
18 hours. After quenching with a saturated solution of NH4Cl, the
aqueous layer was extracted with diethyl ether. The combined ex-
tracts were washed with saturated solutions of NaHCO3 and NaCl,
dried with MgSO4 and the solvents evaporated under vacuum to
in THF (23 mL) was placed in a dry three-necked flask equipped
with a magnetic stirrer, a thermometer, an inlet for nitrogen and a
septum. This solution was cooled to –50 °C. A 2.5  solution of
nBuLi in hexanes (1.03 mL, 2.6 mmol) was slowly added. The re-
sulting red-brown solution was stirred at –50 °C for 2 h. 1,1,3,3-
Tetramethyldisiloxane (0.46 mL, 2.6 mmol) was then added. The
resulting mixture was allowed to warm slowly. After evaporation
of the solvent, the residue was dissolved in THF, precipitated in
cold methanol (–30 °C) and filtered to afford the copolymer 6a as
a pale yellow solid (789 mg, DS = 55%). IR (solution, CH Cl ): ν
˜
2
2
= 3082, 3060, 3026, 2925, 2851, 2123 (SiH), 1601, 1493, 1452, 1265,
875, 759, 739, 699, 539 cm–1. 1H NMR (CDCl3): δ = 7.50–5.80 (br.,
Harom), 4.51 (br., SiH), 2.70–0.50 (br., CH and CH2), 0.35 (br.,
CH3) ppm. Sicont = 1.30 (0.5 mmol Si per g).
afford 2 as a yellow oil (16.1 g, 94%). IR (film, NaCl): ν = 3362,
˜
2952, 2895, 1439, 1416, 1314, 1248, 1202, 1175, 1038, 1014, 976,
947, 846, 697 cm–1. 1H NMR (CDCl3): δ = 7.23 (dd, J = 1.2,
4.9 Hz, 1 H, Harom), 6.97–6.92 (m, 2 H, Harom), 5.11 (m, 1 H, CH),
1.88 (d, J = 4.3 Hz, 1 H, OH), 1.32 (dd, J = 4.3, 7.3 Hz, 2 H,
CH2), –0.03 (s, 9 H, CH3) ppm. 13C NMR (CDCl3): δ = 151.0
(CHarom), 126.4 (CHarom), 124.5 (CHarom), 123.3 (CHarom), 68.3
(CH), 28.9 (CH2), –1.24 (CH3) ppm.
Styrene/Allyldimethyl(5-vinyl-2-thienyl)silane (6b): Following the
general procedure described above for the preparation of 6a, copol-
ymer 6b was obtained from 4 (1.104 g, 0.95 mmol functions of S)
as a pale yellow solid (953 mg, DS = 64%). IR (solution, CH2Cl2):
ν = 3082, 3060, 3026, 2930, 2851, 1629 (C=C allylsilane), 1601,
˜
1493, 1453, 1266, 1029, 739, 698, 539 cm–1. 1H NMR (CDCl3): δ
= 7.70–5.80 (br., Harom), 5.77 (br., =CH), 4.88 (br., =CH2), 2.80–
0.60 (br., CH and CH2), 0.26 (br., CH3) ppm. Sicont = 1.45
(0.5 mmol Si per g).
2-Vinylthiophene (3):[16] A 1  aqueous solution of HCl (62 mL,
62 mmol) was added to a solution of 2 (6.23 g, 31.2 mmol) in di-
ethyl ether (15.5 mL). The biphasic solution was vigorously stirred
at room temperature for 1.5 h. The layers were separated and the
aqueous layer was extracted with diethyl ether. The combined ex-
tracts were washed with a saturated solution of NaHCO3, dried
with MgSO4 and the solvent evaporated. The yellow crude product
was distilled under reduced pressure to afford 3 as a colorless oil
Styrene/Dimethyl(vinyl)(5-vinyl-2-thienyl)silane (6c): Following the
general procedure described above for the preparation of 6a, copol-
ymer 6c was obtained from 4 (6.09 g, 10.3 mmol functions of S) as
a pale yellow solid (6.86 g, DS = 71%). IR (solution, CH Cl ): ν
˜
2
2
= 3417, 3082, 3060, 3026, 2926, 2851, 1601, 1493, 1453, 1265, 1249,
837, 813, 776, 761, 739, 699 cm–1. 1H NMR (CDCl3): δ = 7.60–
5.50 (br., Harom, =CH and =CH2), 3.10–0.60 (br., CH and CH2),
0.34 (br., CH3) ppm. Sicont = 3.09 (1.1 mmol Si per g).
(2.41 g, 71%, two steps). IR (film, NaCl): ν = 3088, 2954, 1795,
˜
1621, 1519, 1440, 1406, 1240, 1201, 1046, 977, 897, 851, 828,
1
699 cm–1. H NMR (CDCl3): δ = 7.17 (m, 1 H, Harom), 6.97 (m, 2
Supported Reagent Styrene/Dimethyl(5-vinyl-2-thienyl)silane (7):
Some beads of resin 5 (2.05 g, 2.2 mmol functions of S) were sus-
pended in THF (56 mL) in a dry three-necked flask equipped with
a magnetic stirrer, a thermometer, an inlet for nitrogen and a sep-
tum. The suspension was cooled to –50 °C. A 1.97  solution of
nBuLi in hexanes (1.62 mL, 3.2 mmol) was slowly added. The mix-
ture was stirred at –50 °C for 2 h and then 1,1,3,3-tetramethyldis-
iloxane (0.56 mL, 3.2 mmol) was added. The suspension was al-
lowed to warm slowly to room temperature over 15 h. After fil-
tration, the beads were washed with THF and then dried under
vacuum to afford resin 7 as orange beads (2.075 g, DS = 47%). IR
H, Harom), 6.82 (dd, J = 11.0, 17.4 Hz, 1 H, CH=CH2), 5.57 (d, J
= 17.4 Hz, 1 H, =CH2), 5.15 (d, J = 11 Hz, 1 H, =CH2) ppm.
13C NMR (CDCl3): δ = 143.0 (Cq,arom), 129.8 (CH=CH2), 127.3
(CHarom), 125.7 (CHarom), 124.3 (CHarom), 113.2 (=CH2) ppm.
Soluble Support Styrene/2-Vinylthiophene (4): 2-Vinylthiophene
(4 g, 36.4 mmol) and AIBN (1.8 g, 11 mmol) were added to a solu-
tion of styrene (32 g, 307.7 mmol) in toluene (216 mL). The solu-
tion was degassed and stirred for 3 days at 80 °C. The solvent was
then evaporated. The residue was dissolved in THF, precipitated in
cold methanol (–30 °C) and the filtered to afford the copolymer
styrene/2-vinyl-thiophene 4 as a pale yellow solid (15.71 g, 44%).
(KBr): ν = 3026, 2924, 2851, 2122 (SiH), 1601, 1493, 1452, 1068,
˜
IR (solution, CH Cl ): ν = 3082, 3060, 3026, 2925, 2850, 1601,
˜
2
2
1029, 759, 698, 539 cm–1. Sicont = 1.40 (0.5 mmol Si per g).
1493, 1453, 1266, 1029, 909, 737, 699, 539 cm–1. 1H NMR (CDCl3):
δ = 7.50–6.10 (br., Harom), 2.80–0.70 (br., CH and CH2) ppm. Scont
= 3.61 (1.1 mmol S per g).
2-(4-Vinylphenyl)thiophene (8):[21] THF (114 mL), thiophene
(3.67 mL, 45.9 mmol) and TMEDA (6.92 mL, 45.9 mmol) were
placed in a dry three-necked flask equipped with a magnetic stirrer,
a thermometer, an inlet for nitrogen and a septum. The solution
was cooled to 0 °C. A 2.5  solution of nBuLi in hexanes
(18.36 mL, 45.9 mmol) was added dropwise. The resulting yellow
mixture was stirred at room temperature for 2 h. Zinc chloride
(7.81 g, 57.4 mmol) and THF (114 mL) were placed in another
three-necked flask equipped with a magnetic stirrer, a refluxing
condenser, an inlet for nitrogen and a septum. The 2-thienyllithium
solution was slowly added to this mixture. The solution was re-
fluxed for 1 h and then cooled to room temperature. Tetrakis(tri-
phenylphosphane)palladium (265 mg, 0.23 mmol), p-bromostyrene
(3 mL, 22.9 mmol) and THF (57 mL) were placed in another three-
necked flask equipped with a magnetic stirrer, a refluxing con-
denser, an inlet for nitrogen and a septum. The 2-thienylzinc chlo-
ride solution was slowly added to this mixture and the solution was
refluxed for 15 h. After cooling, the solution was poured into a
Insoluble Support Styrene/2-Vinylthiophene/Divinylbenzene (5): Per-
fluorooctane (PFO, 160 mL) was placed in a double-coated reactor
equipped with a mechanical stirrer. An organic phase consisting of
styrene (13.68 g, 131.6 mmol), 2-vinylthiophene
3
(1.83 g,
16.6 mmol), divinylbenzene (491 mg, 3 mmol), AIBN (800 mg,
4.9 mmol) and dodecylbenzenesulfonic acid, sodium salt [DBSA,
320 mg (200 mg DBSA per 100 mL PFO)] was added to PFO. The
mixture was polymerized at 80 °C for 24 h whilst stirring at a speed
of 700 rounds per minute. The resulting beads were placed in a
Soxhlet apparatus and washed with THF for 24 h. They were then
dried under vacuum to afford resin 5 as yellow beads (9.71 g, 61%).
IR (KBr): ν = 3025, 2923, 2850, 1601, 1493, 1452, 1068, 1028, 758,
˜
698, 538 cm–1. Scont = 3.52 (1.1 mmol S per g).
Styrene/Dimethyl(5-vinyl-2-thienyl)silane (6a): A solution of copoly-
mer styrene/2-vinylthiophene 4 (1.01 g, 0.87 mmol functions of S)
3906
© 2005 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
Eur. J. Org. Chem. 2005, 3900–3910

New Polymer-Supported Organosilicon Reagents
FULL PAPER
saturated solution of NH4Cl (150 mL). The phases were separated
and the aqueous phase was extracted with CH2Cl2 (3×50 mL). The
combined organic phases were washed with water (2×60 mL), 10%
HCl (3×60 mL) and a saturated solution of NaCl (2×60 mL). The
organic layer was dried with MgSO4 and concentrated under vac-
uum. The residue was purified by chromatography through silica
gel (petroleum ether) to afford 8 as a white solid (3.11 g, 73%). Rf
Styrene/Allyldimethyl[5-(4-vinylphenyl)-2-thienyl]silane (11b): Fol-
lowing the general procedure described above for the preparation
of 11a, copolymer 11b was obtained from 9 (1.408 g, 1.8 mmol
functions S, 1 equiv.) as a brown solid (1.45 g, DS = 93%). IR
(solution, CH Cl ): ν = 3419, 3026, 2924, 1629 (C=C allylsilane),
˜
2
2
1601, 1493, 1452, 1265, 1250, 996, 835, 803, 758, 739, 699 cm–1. 1H
NMR (CDCl3): δ = 7.80–6.05 (br., Harom), 5.83 (br., =CH), 4.90
(petroleum ether) = 0.43. M.p. 107–108 °C. IR (KBr): ν = 3442, (br., =CH2), 2.90–0.60 (br., CH and CH2), 0.37 (br., CH3) ppm.
˜
3070, 3000, 1626, 1499, 1428, 1406, 1122, 991, 905, 852, 843, 822,
694 cm–1. 1H NMR (CDCl3): δ = 7.62 (d, J = 8.2 Hz, 2 H, Harom),
7.46 (d, J = 8.2 Hz, 2 H, Harom), 7.36 (d, J = 3.0 Hz, 1 H, Harom),
7.31 (d, J = 4.9 Hz, 1 H, Harom), 7.13 (d, J = 3.6 Hz, 1 H, Harom),
6.77 (dd, J = 11.0, 17.7 Hz, 1 H, =CH), 5.82 (d, J = 17.4 Hz, 1 H,
=CHHЈ), 5.31 (d, J = 11 Hz, 1 H, =CHHЈ) ppm. 13C NMR
(CDCl3): δ = 144.0 (thiophene Cq), 136.6 (phenyl Cq), 136.2 (vinylic
CH), 133.7 (phenyl Cq), 128.0 (thiophene CH), 126.6 (phenyl CH),
125.9 (phenyl CH), 124.8 (thiophene CH), 123.0 (thiophene CH),
113.8 (vinylic CH2) ppm. MS (EI): m/z (%) = 188 (5), 187 (13), 186
(100), 184 (14), 171 (6), 152 (11), 115 (10), 93 (6), 63 (3). C12H10S
(186.28): calcd. C 77.38, H 5.41, S 17.21; found C 77.33, H 5.24, S
17.60.
Sicont = 3.10 (1.1 mmol Si per g).
Styrene/Dimethyl[5-(4-vinylphenyl)-2-thienyl]silane (12a) Following
Route A: Beads of resin 10 (624 mg, 0.66 mmol functions S) were
suspended in THF (17 mL) in a dry three-necked flask equipped
with a magnetic stirrer, a thermometer, an inlet for nitrogen and a
septum. TMEDA (0.4 mL, 2.6 mmol) was then added to the sus-
pension. The mixture was then cooled to –50 °C. A 1.9  solution
of nBuLi in hexanes (1.39 mL, 2.6 mmol) was slowly added. The
resulting mixture was stirred at –50 °C for 2 h and then 1,1,3,3-
tetramethyldisiloxane (0.47 mL, 2.7 mmol) was added. The suspen-
sion was allowed to warm slowly to room temperature over 15 h.
After filtration, the beads were washed with THF and then dried
under vacuum to afford resin 12a as yellow beads (683 mg, DS =
Synthesis of Soluble Support Styrene/2-(4-Vinylphenyl)thiophene (9):
Compound 8 (514 mg, 2.8 mmol) and AIBN (104 mg, 0.63 mmol)
were added to a solution of styrene (1.56 g, 15 mmol, 1 equiv.) in
toluene (11 mL). The solution was degassed and stirred for 3 days
at 80 °C. The solvent was then evaporated. The residue was dis-
solved in THF, precipitated in cold methanol (–30 °C) and filtered
to afford the copolymer 9 as a pale yellow solid (1.32 g, 64%). IR
85%). IR (KBr): ν = 3025, 2922, 2855, 2123 (SiH), 1601, 1493,
˜
1452, 1251, 1069, 1028, 999, 873, 757, 697, 538 cm–1. Sicont = 2.41
(0.9 mmol Si per g).
Styrene/Allyldimethyl[5-(4-vinylphenyl)-2-thienyl]silane (12b). Route
A: Following the general procedure described above for the prepa-
ration of 12a, polymer 12b was obtained from resin 10 (1.092 g,
1.5 mmol functions of S) and allylchlorodimethylsilane (0.33 mL,
2.3 mmol) as yellow beads (1.19 g, DS = 82%). IR (KBr): ν˜ = 3025,
2923, 2852, 1629 (C=C allylsilane), 1601, 1493, 1452, 1069, 1028,
996, 820, 800, 757, 698, 542 cm–1. Sicont = 2.88 (1 mmol Si per g).
(solution, CH Cl ): ν = 3083, 3060, 3026, 2925, 2851, 1601, 1493,
˜
2
2
1452, 1028, 820, 758, 699 cm–1. H NMR (CDCl3): δ = 7.80–5.90
(br., Harom), 2.80–0.50 (br., CH and CH2) ppm. Scont = 4.30
(1.3 mmol S per g).
1
Insoluble Support Styrene/2-(4-Vinylphenyl)thiophene/Divinylben-
zene (10): An aqueous solution of water (350 mL), acacia powder
(14 g) and sodium chloride (8.8 g) was placed in a double-coated
reactor equipped with a mechanical stirrer. An organic phase con-
sisting of styrene (7.96 g, 76.5 mmol), 2-(4-vinylphenyl)thiophene
(1.8 g, 9.7 mmol), divinylbenzene (286 mg, 1.8 mmol) and AIBN
(502 mg, 3.1 mmol) was suspended in the aqueous solution. The
mixture was polymerized at 80 °C for 24 h whilst stirring at a speed
of 600 rounds per minute with a magnetic stirrer. The resulting
beads were placed in a Soxhlet apparatus and were washed with
THF for 24 h. They were then dried under vacuum to afford resin
Styrene/Allyldiphenyl[5-(4-vinylphenyl)-2-thienyl]silane (12c). Route
B: Beads of resin 10 (1.115 g, 1.4 mmol functions of S) were sus-
pended in THF (37 mL) in a dry three-necked flask equipped with
a magnetic stirrer, a thermometer, an inlet for nitrogen and a sep-
tum. The suspension was then cooled to –50 °C and a 1.9  solu-
tion of nBuLi in hexanes (2.98 mL, 5.7 mmol) was slowly added.
The resulting mixture was stirred at –50 °C for 2 h and then al-
lowed to warm rapidly to 10 °C. The beads turned dark green.
These were washed with THF (3×10 mL) under an inert atmo-
sphere. The beads were then suspended in THF (37 mL) and cooled
to –50 °C and dichlorodiphenylsilane (1.19 mL, 5.7 mmol) was
added. This mixture was stirred at –50 °C for 1 h and then allowed
to warm rapidly to 10 °C. The beads turned orange and were
washed with THF (3×10 mL) under an inert atmosphere. The be-
ads were then suspended in THF (37 mL) and cooled to –50 °C.
Then a 1  solution of allylmagnesium bromide in diethyl ether
(5.7 mL, 5.7 mmol) was added. The resulting mixture was stirred
at –50 °C for 0.5 h and then allowed to warm slowly to room tem-
perature over 15 h. The formation of salts was observed and the
beads turned brown. After filtration, the beads were washed with
THF and then dried under vacuum to afford resin 12c as dark
10 as yellow beads (6.36 g, 63%). IR (KBr): ν = 3025, 2922, 2850,
˜
1601, 1493, 1452, 1067, 1028, 819, 757, 698, 541 cm–1. Scont = 4.47
(1.4 mmol S per g).
Styrene/Dimethyl[5-(4-vinylphenyl)-2-thienyl]silane (11a): A solu-
tion of copolymer 9 (1.051 g, 1.4 mmol functions of S, 1 equiv.) in
THF (37 mL) was placed in a dry three-necked flask equipped with
a magnetic stirrer, a thermometer, an inlet for nitrogen and a sep-
tum. This solution was then cooled to –50 °C. A 2.5  solution of
nBuLi in hexanes (0.84 mL, 2.1 mmol, 1.5 equiv.) was slowly
added. The resulting red-brown solution was stirred at –50 °C for
2 h and then 1,1,3,3-tetramethyldisiloxane (0.37 mL, 2.1 mmol,
1.5 equiv.) was added. The resulting mixture was allowed to warm
slowly to room temperature. After evaporation of the solvent, the
residue was dissolved in THF, precipitated in cold methanol (–
30 °C) and filtered to afford the copolymer 11a as a brown solid
brown beads (1.403 g, DS = 60%). IR (KBr): ν = 3023, 2921, 1628
˜
(C=C allylsilane), 1600, 1492, 1452, 1428, 1111, 1067, 1028, 997,
759, 698, 534 cm–1. Sicont = 1.83 (0.7 mmol Si per g).
Styrene/Diphenyl(4-phenylbuta-1,3-dienyl)[5-(4-vinylphenyl)-2-thien-
yl]silane (12d): Following the general procedure described above for
the preparation of 12c, polymer 12d was obtained from resin 10
(1.104 g, 1.4 mmol functions of S), dichlorodiphenylsilane
(1.18 mL, 5.6 mmol) and 4-phenylbuta-1,3-dienyllithium as green
(975 mg, DS = 56%). IR (solution, CH Cl ): ν = 3419, 3025, 2925,
˜
2
2
2125 (SiH), 1601, 1493, 1452, 1253, 1074, 1000, 874, 760, 699 cm–1.
1H NMR (CDCl3): δ = 7.80–5.90 (br., Harom), 4.61 (br., SiH), 2.80–
0.60 (br., CH and CH2), 0.44 (br., CH3) ppm. Sicont = 2.02
(0.7 mmol Si per g).
beads (1.325 g, DS = 55%). IR (KBr): ν = 3023, 2920, 1653, 1635,
˜
Eur. J. Org. Chem. 2005, 3900–3910
www.eurjoc.org
© 2005 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
3907

A. Fauvel, H. Deleuze, Y. Landais
1600, 1492, 1452, 1429, 1112, 1067, 1028, 757, 698, 536, 517 cm–1. ica gel (petroleum ether) to afford (4-bromobuta-1,3-dienyl)ben-
FULL PAPER
Sicont = 1.60 (0.6 mmol Si per g).
zene as a yellow solid (984 mg, 37%). Rf (petroleum ether) = 0.41.
1H NMR (CDCl3): δ = 7.60–6.10 (m, 9 H). 13C NMR (CDCl3): δ
= 137.6, 136.6 (Cq,arom–E), 136.5 (Cq,arom–Z), 136.0 (s), 133.3 (s),
132.7 (s), 128.7 (s), 128.3 (s), 128.0 (s), 126.8 (s), 126.5 (s), 126.0
(s), 124.3 (s), 108.9 (s, =CHBr-E), 108.5 (s, =CHBr-Z) ppm. This
dienyl bromide (0.73 g, 3.5 mmol) and diethyl ether (24 mL) were
placed in a dry three-necked flask equipped with a thermometer,
an inlet for nitrogen and a septum. The yellow solution was cooled
to –90 °C and a 1.38  solution of tBuLi in pentane (5.07 mL,
7 mmol) was slowly added. The mixture turned dark brown and
was stirred at –90 °C for 1.5 h to afford crude 4-phenylbuta-1,3-
dienyllithium, which was used directly in the preparation of 12d.
Styrene/Cyclopenta-2,4-dienyldiphenyl[5-(4-vinylphenyl)-2-thienyl]si-
lane (12e): Beads of resin 10 (1.113 g, 1.4 mmol functions S) were
suspended in THF (37 mL) in a dry three-necked flask equipped
with a magnetic stirrer, a thermometer, an inlet for nitrogen and a
septum. The suspension was cooled to –50 °C and then a 2.22 
solution of nBuLi in hexanes (2.55 mL, 5.6 mmol) was slowly
added. The mixture was stirred at –50 °C for 2 h and then allowed
to warm rapidly to 10 °C. The beads turned dark green. They were
washed with THF (3×10 mL) under an inert atmosphere, then sus-
pended in THF (37 mL) and cooled to –50 °C. Then dichlorodi-
phenylsilane (1.19 mL, 5.6 mmol) was added. The resulting mixture
was stirred at –50 °C for 1 h and then allowed to warm rapidly
to 10 °C. The beads turned orange. They were washed with THF
(3×10 mL) under an inert atmosphere. The beads were then sus-
pended in THF (20 mL) and cooled to –78 °C and a solution of
cyclopentadienyllithium in THF was added [5.6 mmol; prepared
from freshly distilled cyclopentadiene (0.46 mL, 5.6 mmol) and a
2.22  solution of nBuLi in hexanes (2.82 mL, 6.3 mmol) in THF
(16.9 mL) at –78 °C for 1 h]. The resulting mixture was stirred at –
78 °C for 1 h and then allowed to warm slowly to room tempera-
ture over 15 h. After filtration, the beads were washed with THF
and dried under vacuum to afford resin 12e as brown beads
Styrene/(3-Benzo[1,3]dioxol-5-ylpropyl)dimethyl(5-vinyl-2-thienyl)si-
lane (15a): Safrole (0.44 mL, 3 mmol) and a 10% solution of
hexachloroplatinic acid (75 µL) were added to a solution of copoly-
mer 6a (677 mg, 0.3 mmol functions of Si) in toluene (35 mL). The
resulting mixture was heated at 80 °C until completion of the reac-
tion. The reaction was monitored by IR spectroscopy (disappear-
ance of the Si–H band at 2114 cm–1). After evaporation of the sol-
vent, the residue was dissolved in THF, precipitated in cold meth-
anol (–30 °C) and filtered to afford copolymer 15a as a grey solid
(633 mg). IR (solution, CH Cl ): ν = 3027, 2921, 1698, 1602, 1494,
˜
2
2
1454, 1368, 1265, 1069, 1029, 909, 746, 697 cm–1. 1H NMR
(CDCl3): δ = 7.80–5.90 (br., Harom), 5.87 (br., OCH2O), 2.70–0.20
(br., CH, CH2, CH3) ppm.
(1.384 g, DS = 63%). IR (KBr): ν = 3024, 2922, 1630 (C=C allylsi-
˜
lane), 1601, 1493, 1452, 1429, 1112, 1067, 1028, 998, 757, 698,
537 cm–1. Sicont = 1.88 (0.7 mmol Si per g).
Styrene/(3-Benzo[1,3]dioxol-5-ylpropyl)dimethyl(5-vinyl-2-thienyl)si-
lane (15b): Safrole (1.2 mL, 8.1 mmol) and a 10% solution of
hexachloroplatinic acid (105 µL) were added to a suspension of be-
ads of resin 7 (1.556 g, 0.78 mmol functions of Si) in toluene
(43 mL). The mixture was stirred at 80 °C for 24 h. After filtration,
the beads were washed with THF and then dried under vacuum to
4-Phenylbuta-1,3-dienyllithium (13):[26b] THF (5.05 mL) and dicy-
clohexylamine (1.26 mL, 6.3 mmol) were placed in a dry three-
necked flask equipped with a thermometer, an inlet for nitrogen
and a septum. The solution was then cooled to –78 °C and a 1.85 
solution of nBuLi in hexanes (3.43 mL, 6.3 mmol) was slowly
added. The mixture turned yellow and was stirred at –78 °C for
15 min. THF (3.8 mL), dibromomethane (0.45 mL, 6.3 mmol) and
cinnamaldehyde (0.4 mL, 3.2 mmol) were placed in another dry
three-necked flask equipped with a thermometer, an inlet for nitro-
gen and a septum. The resulting solution was cooled to –78 °C and
the solution of lithium dicyclohexylamide was added slowly to the
second solution. The mixture turned yellow, then orange and was
stirred at –78 °C for 1.5 h. The reaction mixture was then quenched
with a 10% aqueous solution of HCl (5 mL) at –78 °C. After fil-
tration, the aqueous phase was extracted with diethyl ether
(3×5 mL) and the combined organic phases were washed with a
saturated solution of NaCl (3×15 mL), dried with MgSO4 and
concentrated under vacuum. The residue was purified by
chromatography through silica gel (petroleum ether/EtOAc, 92:8)
afford resin 15b as brown beads (1.596 g). IR (KBr): ν = 3026,
˜
2923, 2851, 1602, 1493, 1452, 1249, 1068, 1029, 907, 803, 758, 698,
539 cm–1.
Styrene/(3-Benzo[1,3]dioxol-5-ylpropyl)dimethyl[5-(4-vinylphenyl)-2-
thienyl]silane (15c): Safrole (0.93 mL, 6.3 mmol) and a 10% solu-
tion of hexachloroplatinic acid (127 µL) were added to a solution
of copolymer 11a (936 mg, 0.67 mmol functions of Si) in toluene
(33 mL). The resulting mixture was stirred at 80 °C until comple-
tion of the reaction. The reaction was monitored by IR spec-
troscopy (disappearance of the Si–H band at 2126 cm–1). After
evaporation of the solvent, the residue was dissolved in THF, pre-
cipitated in cold methanol (–30 °C) and filtered to afford the copol-
ymer 15c as a grey solid (954 mg). IR (solution, CH Cl ): ν = 3026,
˜
2
2
2925, 1601, 1492, 1452, 1264, 1250, 1073, 1040, 999, 804, 759, 737,
to afford 1,1-dibromo-4-phenylbut-3-en-2-ol as
(429 mg, 44%). Rf (petroleum ether/EtOAc, 9:1) = 0.21. IR (film,
a
yellow oil
1
700 cm–1. H NMR (CDCl3): δ = 7.75–6.05 (br., Harom), 5.88 (br.,
OCH2O), 2.90–0.10 (br., CH, CH2, CH3) ppm.
NaCl): ν = 3396 (OH), 3058, 3026, 1651, 1494, 1449, 1150, 1071,
˜
Styrene/(3-Benzo[1,3]dioxol-5-ylpropyl)dimethyl[5-(4-vinylphenyl)-2-
thienyl]silane (15d): Safrole (0.73 mL, 4.9 mmol) and a 10% solu-
tion of hexachloroplatinic acid (120 µL) were added to a suspen-
sion of beads of resin 12a (893 mg, 0.83 mmol functions of Si) in
toluene (26 mL). The mixture was stirred at 80 °C for 24 h. After
filtration, the beads were washed with THF and then dried under
1028, 966, 752, 718, 693 cm–1. 1H NMR (CDCl3): δ = 7.37–7.19
(m, 5 H, Harom), 6.73 (d, J = 15.8 Hz, 1 H, Ph-CH=), 6.23 (dd, J
= 6, 15.8 Hz, 1 H, =CH-CHOH), 5.66 (d, J = 3.7 Hz, 1 H, CHBr2),
4.52 (m, 1 H, CHOH) ppm. 13C NMR (CDCl3): δ = 135.8 (Cq,arom),
134.8 (Ph-CH=), 128.7 (CHarom), 128.4 (CHarom), 126.8 (CHarom),
125.4 (=CH-CHOH), 77.2 (CHOH), 51.4 (CHBr2) ppm. Activated
zinc (4.18 g, 63.9 mmol) was added to a solution of this alcohol
(3.9 g, 12.8 mmol) in dichloromethane (41 mL). The resulting mix-
ture was cooled to 0 °C and acetic acid (2.93 mL, 51.1 mmol) was
slowly added. The solution was stirred vigorously at room tempera-
ture for 21 h. Water (5 mL) and K2CO3 were added until the pH =
7. After filtration, the aqueous phase was extracted with CH2Cl2.
The organic layer was dried with MgSO4 and concentrated under
vacuum. The residue was purified by chromatography through sil-
vacuum to afford resin 15d as brown beads (954 mg). IR (KBr): ν
˜
= 3025, 2922, 2850, 1601, 1493, 1452, 1250, 1069, 1029, 999, 819,
803, 757, 698, 540 cm–1.
(3-Benzo[1,3]dioxol-5-ylpropyl)dimethylsilanol (16) from 15a: A 1 
solution of TBAF in THF (1.1 mL, 1.1 mmol) was added to a solu-
tion of copolymer 15a (617 mg) in DMF (3.9 mL). The mixture
was stirred at room temperature for 24 h. After evaporation of the
solvent, the residue was dissolved in THF, precipitated in cold
3908
© 2005 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
Eur. J. Org. Chem. 2005, 3900–3910

New Polymer-Supported Organosilicon Reagents
FULL PAPER
methanol (–30 °C) and filtered to afford the copolymer 4. The fil-
trate was evaporated, dissolved in EtOAc and then washed with
water. The organic layer was dried with MgSO4 and concentrated
under vacuum to afford silanol 16 as a brown oil (76 mg), which
used in the next step without further purification. Rf (petroleum
[5-(4-Ethylphenyl)-2-thienyl]dimethylsilane (19): A solution of 2-(4-
ethylphenyl)thiophene (18) (230 mg, 1.2 mmol) in THF (2.5 mL)
was placed in a dry three-necked flask equipped with a thermome-
ter, an inlet for nitrogen and a septum and cooled to –50 °C. A
1.89  solution of nBuLi in hexanes (0.72 mL, 1.4 mmol) was
slowly added. The resulting mixture turned dark green then pale
ether/EtOAc, 98:2) = 0.14. IR (film, NaCl): ν = 2953, 2925, 1503,
˜
1490, 1443, 1251, 1188, 1042, 938, 839, 801 cm–1. 1H NMR green. The solution was stirred at –50 °C for 2 h and then chlorodi-
(CDCl3): δ = 6.68 (m, 3 H, Harom), 5.92 (s, 2 H, OCH2O), 2.54 (t,
J = 7.6 Hz, 2 H, CH2Ar), 1.59 (m, 2 H, CH2-CH2-CH2), 0.54 (m,
methylsilane (0.2 mL, 1.8 mmol) was added. The solution was al-
lowed to warm rapidly to 0 °C and turned yellow. The reaction was
2 H, SiCH2), 0.04 (s, 6 H, CH3) ppm. 13C NMR (CDCl3): δ = 147.4 quenched with a saturated solution of NH4Cl (5 mL). The aqueous
(Cq,arom), 145.4 (Cq,arom), 136.6 (Cq,arom), 121.1 (CHarom), 108.9 layer was extracted with diethyl ether (3×5 mL) and the combined
(CHarom), 108.0 (CHarom), 100.6 (OCH2O), 39.3 (CH2Ar), 25.6 organic phases were washed with water (3×15 mL), dried with
(CH2-CH2-CH2), 18.0 (SiCH2), 0.3 (s, CH3) ppm.
MgSO4 and concentrated under vacuum. The residue was purified
by chromatography through silica gel (petroleum ether) to afford
19 as a white solid (235 mg, 78%). Rf (petroleum ether) = 0.51.
[3-(Benzo[1,3]dioxol-5-yl)propyl]dimethylsilanol (16) from 15b: Fol-
lowing the general procedure described above for the preparation
of 16 from 15a, treatment of resin 15b (1.563 g) with a 1  solution
of TBAF in THF (1.7 mL, 1.7 mmol) afforded silanol 16 as a
brown oil (204 mg).
M.p. 31 °C. IR (KBr): ν = 2963, 2125 (SiH), 1434, 1250, 1000, 951,
˜
873, 833, 802, 766 cm–1. 1H NMR (CDCl3): δ = 7.55 (d, J = 8.2 Hz,
2 H, Harom), 7.34 (d, J = 3.4 Hz, 1 H, Harom), 7.23 (m, 3 H, Harom),
4.59 (m, 1 H, SiH), 2.67 (q, J = 7.6 Hz, 2 H, CH2), 1.27 (t, J =
7.6 Hz, 3 H, CH3-CH2), 0.42 [d, J = 3.7 Hz, 6 H, Si(CH3)2] ppm.
13C NMR (CDCl3): δ = 150.5 (Cq,arom), 143.8 (Cq,arom), 136.1
(CHarom), 135.5 (Cq,arom), 128.3 (CHarom), 126.0 (CHarom), 124.0
(CHarom), 28.6 (CH2), 15.5 (CH3-CH2), –2.8 [Si(CH3)2] ppm. MS
(EI): m/z (%) = 247 (8), 246 (41), 231 (100), 205 (15), 188 (22), 173
(65), 171 (16), 128 (28), 115 (67), 89 (16), 77 (29), 58 (38), 43 (45),
40 (61). HRMS C14H18SSi: calcd. 246.0897; found 246.0898.
16 from 15c: Following the general procedure described above for
the preparation of 16 from 15a, treatment of copolymer 15c
(950 mg) with a 1  solution of TBAF in THF (1.3 mL, 1.3 mmol)
afforded silanol 16 as a brown oil (192 mg).
16 from 15d: Following the general procedure described above for
the preparation of 16 from 15a, treatment of resin 15d (940 mg)
with a 1  solution of TBAF in THF (1.2 mL, 1.2 mmol) afforded
silanol 16 as a brown oil (124 mg).
[3-(Benzo[1,3]dioxol-5-yl)propyl][5-(4-ethylphenyl)-2-thienyl]dimeth-
ylsilane (20): Safrole (0.75 mL, 5.1 mmol) and a 10% solution of
hexachloroplatinic acid (0.11 mL) were added to a solution of 19
(1.236 g, 5 mmol) in toluene (10 mL) under an inert atmosphere.
The solution was stirred at 80 °C for 3.5 h. After evaporation of
the solvent, the residue was dissolved in EtOAc (40 mL) and
washed with water (3×15 mL). The organic layer was dried with
MgSO4 and concentrated under vacuum. The residue was purified
by chromatography through silica gel (petroleum ether/EtOAc,
99:1) to afford 20 as a pale blue oil (325 mg, 16%). Rf (petroleum
(3-Benzo[1,3]dioxol-5-yl)propan-1-ol (17):[30] A mixture of silanol 16
(192 mg, 0.8 mmol), potassium fluoride (221 mg, 3.8 mmol) and
potassium hydrogencarbonate (381 mg, 3.8 mmol) was placed un-
der nitrogen in a round flask. DMF (9.3 mL) was added. This mix-
ture was cooled to 0 °C and a 35% aqueous solution of H2O2
(2.22 mL, 25.4 mmol) was slowly added and the resulting solution
stirred at 60 °C for 24 h. The reaction was quenched with solid
sodium thiosulfate. After evaporation of the solvent, the residue
was dissolved in EtOAc and washed with water. The organic phase
was dried with MgSO4 and concentrated under vacuum. The resi-
due was purified by chromatography through silica gel (petroleum
ether/EtOAc, 7:3) to afford alcohol 17 as a pale yellow oil (56 mg,
24%, four steps). Rf (petroleum ether/EtOAc, 7:3) = 0.34. 1H NMR
(CDCl3): δ = 6.69 (m, 3 H, Harom), 5.92 (s, 2 H, OCH2O), 3.66 (t,
J = 6.4 Hz, 2 H, CH2OH), 2.63 (t, J = 7.6 Hz, 2 H, CH2Ar), 1.85
(m, 2 H, CH2-CH2-CH2), 1.32 (s, 1 H, OH) ppm. 13C NMR
(CDCl3): δ = 147.5 (Cq,arom), 145.5 (Cq,arom), 135.6 (Cq,arom), 121.0
(CHarom), 108.8 (CHarom), 108.1 (CHarom), 100.7 (OCH2O), 61.9
(CH2OH), 34.3 (CH2-CH2-CH2), 31.7 (CH2Ar) ppm.
ether/EtOAc, 98:2) = 0.41. IR (film, NaCl): ν = 2962, 2927, 1502,
˜
1489, 1443, 1249, 1107, 1041, 997, 950, 834, 804, 778 cm–1. 1H
NMR (CDCl3): δ = 7.59 (d, J = 7.9 Hz, 2 H, Harom), 7.37 (d, J =
3.4 Hz, 1 H, Harom), 7.24 (m, 3 H, Harom), 6.70 (m, 3 H, Harom),
5.94 (s, 2 H, OCH2O), 2.70 (q, J = 7.5 Hz, 2 H, CH3-CH2), 2.60
(t, J = 7.5 Hz, 2 H, CH2-CH2Ar), 1.71 (m, 2 H, CH2-CH2-CH2),
1.30 (t, J = 7.5 Hz, 3 H, CH3-CH2), 0.86 (m, 2 H, SiCH2), 0.37 [s,
6 H, Si(CH3)2] ppm. 13C NMR (CDCl3): δ = 149.9 (Cq,arom), 147.4
(Cq,arom), 145.5 (Cq,arom), 143.6 (Cq,arom), 138.1 (Cq,arom), 136.3
(Cq,arom), 135.2 (s, CHarom), 131.9 (Cq,arom), 128.3 (CHarom), 126.0
(CHarom), 123.9 (CHarom), 121.2 (CHarom), 108.9 (CHarom), 108.0
(CHarom), 100.6 (OCH2O), 39.3 (CH2-CH2Ar), 28.5 (CH3-CH2),
26.1 (CH2-CH2-CH2), 16.2 (SiCH2), 15.4 (CH3-CH2), –1.9
[Si(CH3)2] ppm. MS (LSIMS): m/z (%) = 407 (26), 393 (6), 245
(42), 221 (100), 201 (30), 179 (8), 135 (10).
2-(4-Ethylphenyl)thiophene (18): A solution of 2-(4-vinylphenyl)
thiophene (8) (1.15 g, 6.18 mmol, 1 equiv.) and palladium [10 wt.-%
on activated carbon (1.15 g)] in methanol (12.5 mL) was vigorously
stirred under hydrogen at room temperature for 15 h. After fil-
tration through Celite, the residue was concentrated under vacuum.
The residue was purified by chromatography through silica gel (pe-
troleum ether) to afford 18 as a white solid (1.012 g, 87%). Rf (pe-
Desilylation of Silane 20 with TBAF: A 1  solution of TBAF in
THF (0.4 mL, 0.4 mmol) was added to a solution of silane 20
(161 mg, 0.39 mmol) in DMF (10 mL) and the solution was stirred
at room temperature for 1.5 h. After evaporation of the solvents,
the residue was dissolved in EtOAc and washed with water. The
organic layer was dried with MgSO4 and concentrated under vac-
uum. The residue was purified by chromatography through silica
gel (petroleum ether) to afford 18 as a white solid (67 mg, 91%),
spectroscopically identical to that prepared above.
troleum ether) = 0.44. M.p. 40–41 °C. IR (KBr): ν = 2960, 2926,
˜
1501, 1429, 1119, 1053, 851, 819, 704 cm–1. 1H NMR (CDCl3): δ
= 7.60 (d, J = 8.3 Hz, 2 H, Harom), 7.31 (m, 4 H, Harom), 7.13 (m,
1 H, Harom), 2.73 (q, J = 7.5 Hz, 2 H, CH2), 1.33 (t, J = 7.5 Hz, 3
H, CH3) ppm. 13C NMR (CDCl3): δ = 144.5 (Cq,arom), 143.6
(Cq,arom), 131.9 (Cq,arom), 128.3 (CHarom), 127.9 (CHarom), 125.9
(CHarom), 124.2 (CHarom), 122.6 (CHarom), 28.5 (CH2), 15.5
(CH3) ppm. MS (EI): m/z (%) = 189 (5), 188 (42), 173 (100), 171
(9), 128 (16), 115 (16), 102 (7), 58 (10), 45 (12). C12H12S (188.29):
calcd. C 76.55, H 6.42, S 17.03; found C 75.92, H 6.58, S 16.99.
2-Bromo-5-(4-ethylphenyl)thiophene (22): Peracetic acid (0.12 mL,
1.9 mmol) was slowly added to a cooled solution of silane 20
Eur. J. Org. Chem. 2005, 3900–3910
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© 2005 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
3909

A. Fauvel, H. Deleuze, Y. Landais
FULL PAPER
[10] I. Fleming, R. Henning, D. C. Parker, H. E. Plaut, P. E. J. San-
derson, J. Chem. Soc., Faraday Trans. 1 1995, 317–337.
[11] M. J. Farrall, J. M. J. Fréchet, J. Org. Chem. 1976, 41, 3877–
3882.
(153 mg, 0.37 mmol), KBr (53 mg, 0.45 mmol) and sodium acetate
(88 mg, 1.1 mmol) in AcOH (1.9 mL). The mixture was allowed to
warm to room temperature and then cooled to 0 °C again. More
sodium acetate (264 mg, 3.2 mmol) and peracetic acid (0.37 mL,
5.6 mmol) were then slowly added and the solution was stirred at
room temperature for 24 h. The reaction was quenched with a 25%
aqueous solution of sodium thiosulfate (8 mL), EtOAc was added
and the layers were separated. The aqueous layer was extracted
with EtOAc. The organic layer was washed with saturated solutions
of NaHCO3 and NaCl, dried with MgSO4 and concentrated under
vacuum. The residue was purified by chromatography through sil-
ica gel (petroleum ether, then petroleum ether/EtOAc, 7:3) to afford
alcohol 17 as a pale yellow oil (52 mg, 78%) and 22 as a white
solid (93 mg, 94%). Compound 22: 1H NMR (CDCl3): δ = 7.45
(d, J = 8.2 Hz, 2 H, Harom), 7.22 (d, J = 8.2 Hz, 2 H, Harom), 7.02
(m, 2 H, Harom), 2.68 (q, J = 7.6 Hz, 2 H, CH2), 1.27 (t, J = 7.6 Hz,
3 H, CH3) ppm.
[12] H. Gilman, D. A. Shirley, J. Am. Chem. Soc. 1949, 71, 1870–
1871.
[13] O. Andrey, L. Ducry, Y. Landais, D. Planchenault, V. Weber,
Tetrahedron 1997, 53, 4339–4352.
[14] A. A. H. Al Kadhumi, P. Hodge, F. G. Thorpe, Polymer 1985,
26, 1695–1700.
[15] J. M. Harris, M. D. Keranen, H. Nguyen, V. G. Young, G. A.
O’Doherty, Carbohydr. Res. 2000, 328, 17–36.
[16] W. S. Emerson, T. M. Patrick, Jr., Org. Synth. 1958, 38, 980–
983.
[17] J. C. Bevington, T. N. Huckerby, M. G. Liu, F. G. Thorpe, Eur.
Polym. J. 1987, 23, 95–97.
[18] L. Porres, H. Deleuze, Y. Landais, J. Chem. Soc., Perkin Trans.
1 2002, 2198–2203.
[19] The yields and degrees of substitution were calculated by using
the following equations, as reported by Farrall and Frechet.[11]
(1) Yield = (M/Mi)×(Sicont/Scont)×100, where M is the weight
of the support, Mi is the weight of the initial support, Sicont is
the silicon content in mmolg–1 and Scont is the sulfur content
in mmolg–1 (obtained by elemental analysis). (2) Degree of
substitution, DS = Sicont/Scont/(1 – Sicont ×Msubstituent)]×100,
where Sicont is the silicon content in molg–1, Scont is the
sulfur content in molg–1 (obtained by elemental analysis), and
Msubstituent is the molecular weight of the substituent attached
to the polymeric support.
Acknowledgments
We thank the CNRS and the Institut Universitaire de France for
financial support and the MNERT for a grant to A. F.
[1] a) P. H. Toy, T. S. Reger, P. Garibay, J. C. Garno, J. A. Mali-
kayil, G.-Y. Liu, K. D. Janda, J. Comb. Chem. 2001, 3, 117–
124; b) R. E. Dolle, K. H. Nelson Jr., J. Comb. Chem. 1999, 1,
235–282; c) M. Lebl, J. Comb. Chem. 1999, 1, 3–24; d) S.
[20] A. Fauvel, Ph. D. Thesis, University of Bordeaux-1, 2004.
[21] A. Ishibashi, M. Sakai, M. Wakabayashi, Patent YKK CORP,
US 5789600, 1998.
Booth, P. H. H. Hermkens, H. C. J. Ottenheijm, D. C. Rees, [22] K. Uchida, Y. Kido, T. Yamaguchi, M. Irie, Bull. Chem. Soc.
Tetrahedron 1998, 54, 15385–15443; e) P. H. Toy, K. D. Janda, Jpn. 1998, 71, 1101–1108.
Acc. Chem. Res. 2000, 33, 546–554; f) C. M. Baldino, J. Comb. [23] A. R. Vairo, D. B. Gooding, K. D. Janda, J. Comb. Chem.
Chem. 2000, 2, 89–103; g) D. J. Gravert, K. D. Janda, Chem.
Rev. 1997, 97, 489–509; h) S. A. Kates, F. Albericio (Eds.), So-
lid-Phase Synthesis: A Practical Guide, Marcel Dekker, New
York, 2000; i) G. Jung (Ed.), Combinatorial Peptide and Non-
peptides Libraries, A Handbook, VCH, Weinheim, 1996.
[2] a) Y. Lee, R. B. Silverman, Tetrahedron 2001, 57, 5339–5352;
b) T. Doi, M. Sugiki, H. Yamada, T. Takahashi, J. A. Porco Jr.,
Tetrahedron Lett. 1999, 40, 2141–2144; c) Y. Hu, J. A.
Porco, Jr., Tetrahedron Lett. 1998, 39, 2711–2714; d) Y. Hu,
J. A. Porco Jr., Tetrahedron Lett. 1999, 40, 3289–3292; e) F. X.
Woolard, J. Paetsch, J. A. Ellman, J. Org. Chem. 1997, 62,
6102–6103; f) M. J. Plunkett, J. A. Ellman, J. Org. Chem. 1995,
60, 6006–6007.
[3] a) A. Hirao, T. Hatayama, S. Nakahama, Macromolecules
1987, 20, 1505–1509; b) T. Taki, A. Hirao, S. Nakahama, Mac-
romolecules 1991, 24, 1455–1458.
[4] H. D. H. Stover, P. Z. Lu, J. M. J. Fréchet, Polym. Bull. (Berlin)
1991, 25, 575–582.
[5] S. Itsuno, D. Chao, K. Ito, J. Polym. Sci.: Part A: Polym. Chem.
1993, 31, 287–291.
[6] C. W. Lindsley, J. C. Hodges, G. F. Filzen, B. M. Watson, A. G.
Geyer, J. Comb. Chem. 2000, 2, 550–559.
2000, 2, 330–333.
[24] B. Wang, L. Chen, K. Kim, Tetrahedron Lett. 2001, 42, 1463–
1466.
[25] T. H. Chan, W. Q. Huang, J. Chem. Soc., Chem. Commun.
1985, 909–911.
[26] a) R. Angelaud, Ph. D. Thesis, University of Lausanne, 1997;
b) D. R. Williams, K. Nishitani, W. Bennett, S. Y. Sit, Tetrahe-
dron Lett. 1981, 22, 3745–3748.
[27] Y. Landais, L. Parra-Rapado, Eur. J. Org. Chem. 2000, 401–
418.
[28] J. L. Speier, J. A. Webster, G. H. Barnes, J. Am. Chem. Soc.
1957, 79, 974–979.
[29] K. Tamao, T. Kakui, M. Kumada, J. Am. Chem. Soc. 1978,
100, 2268–2269.
[30] P. C. Lima, L. M. Lima, K. C. M. da Silva, P. H. O. Léda,
A. L. P. de Miranda, C. A. M. Fraga, E. J. Barreiro, Eur. J.
Med. Chem. 2000, 35, 187–203.
[31] M. Gingras, Tetrahedron Lett. 1991, 32, 7381–7384.
[32] K. A. Scheidt, H. Chen, B. C. Follows, S. R. Chemler, D. S.
Coffey, W. R. Roush, J. Org. Chem. 1998, 63, 6436–6437.
[33] The efficiency of the introduction of the allyl group using route
B has been demonstrated through the carboazidation of allylsi-
lane 12b. Carboazidation of 12b, prepared through route A
(Scheme 7) or route B (Scheme 8) gave similar results; a) C.
Ollivier, P. Renaud, J. Am. Chem. Soc. 2001, 123, 4717–4727;
b) L. Chabaud, Y. Landais, P. Renaud, Org. Lett. 2002, 4,
4257–4260; c) P. Panchaud, L. Chabaud, Y. Landais, C. Olliv-
ier, P. Renaud, S. Zigmantas, Chem. Eur. J. 2004, 10, 3606–
3614.
[7] a) K. W. Pepper, H. M. Paisley, M. A. Young, J. Chem. Soc.
1953, 4097–4105; b) R. Duboc, M. Savignac, J. P. Genet, J.
Organomet. Chem. 2002, 643, 512–515; c) M. Schuster, N.
Lucas, S. Blechert, Chem. Commun. 1997, 823–824; d) M.
Schuster, S. Blechert, Tetrahedron Lett. 1998, 39, 2295–2298.
[8] a) R. Angelaud, O. Babot, T. Charvat, Y. Landais, J. Org.
Chem. 1999, 64, 9613–9624; b) L. Chabaud, P. James, Y. Land-
ais, Eur. J. Org. Chem. 2004, 3173–3199.
Received: April 11, 2005
Published Online: July 12, 2005
[9] a) G. R. Jones, Y. Landais, Tetrahedron 1996, 52, 7599–7662;
b) I. Fleming, Chemtracts: Org. Chem. 1996, 9, 1–64; c) K.
Tamao, Adv. Silicon Chem. 1996, 3, 1–62.
Note: Minor changes have been made to this manuscript
since its publication in Eur. J. Org. Chem. Early View.
3910
© 2005 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
Eur. J. Org. Chem. 2005, 3900–3910