Polymer-micelle incarcerated ruthenium catalysts for oxidation of alcohols and sulfides

Article abstract of DOI:10.1016/j.tet.2005.08.123

Highly active immobilized ruthenium catalysts, which can be used for oxidation of alcohols and sulfides, were developed on the basis of the polymer-micelle incarcerated (PMI) method. The catalysts could be recovered and reused several times without loss of activity and no metal leaching was observed. Selection of micelle-forming conditions and polymer structures were key in achieving high activities. TEM and SEM analyses were conducted to observe the structures of PMI-Ru.

Full text of DOI:10.1016/j.tet.2005.08.123

Tetrahedron 61 (2005) 12177–12185
Polymer-micelle incarcerated ruthenium catalysts for oxidation
of alcohols and sulfides
Hiroyuki Miyamura, Ryo Akiyama, Tasuku Ishida, Ryosuke Matsubara, Masahiro Takeuchi
*
and Shu Kobayashi
¯
Graduate School of Pharmaceutical Sciences, The University of Tokyo, the HFRE Division, ERATO,
Japan Science and Technology Agency (JST), Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
Received 6 August 2005; revised 26 August 2005; accepted 26 August 2005
Available online 4 November 2005
Abstract—Highly active immobilized ruthenium catalysts, which can be used for oxidation of alcohols and sulfides, were developed on the
basis of the polymer-micelle incarcerated (PMI) method. The catalysts could be recovered and reused several times without loss of activity
and no metal leaching was observed. Selection of micelle-forming conditions and polymer structures were key in achieving high activities.
TEM and SEM analyses were conducted to observe the structures of PMI-Ru.
q 2005 Elsevier Ltd. All rights reserved.
1. Introduction
structures plays a key role in obtaining higher catalytic
activities in the polymer-micelle incarcerated (PMI)
method. In this article, we describe efficient immobilized
ruthenium catalysts, which have high activity for oxidation
reactions (Figs. 1 and 2).
Immobilized catalysts are now of great interest for two
principle reasons. First, they are crucial for achieving
environmentally benign chemical synthesis,1 the catalysts
are readily recovered and reused, and total waste is
decreased. Secondly, immobilized catalysts play a key
role for combinatorial library synthesis.1d,2 Synthetic
procedures are simplified using immobilized catalysts, and
their application to automation is facile. However, whereas
various immobilized catalysts have been developed, many
are less active than the original non-immobilized catalysts.
Oxidation reactions are very important transformations in
organic synthesis,3 and whilst several metal-based oxidizing
reagents have been developed, in many cases stoichiometric
amounts of metal oxidants are needed, and thus large
amounts of metal-containing waste is formed. In this aspect,
oxidation reactions using a catalytic amount of a metal
reagent are very attractive4 and several successful examples
of catalytic oxidation of alcohols have been reported.5
Among these catalysts, some ruthenium species have been
widely developed and used as efficient catalysts for
oxidation reactions.6 Quite recently we have reported a
novel immobilized ruthenium catalyst for the oxidation of
alcohols and sulfides.7 In the course of our investigation to
develop efficient immobilized catalysts, we have found that
choice of micelle-forming conditions and polymer
Figure 1.
Figure 2.
2. Results and discussion
Keywords: Ruthenium catalysts; Oxidation of alcohols and sulfides;
Polymer-micelle incarcerated (PMI) method.
Recently we have developed a novel polymer incar-
ceration immobilization method for metal catalysts using
*
Corresponding author. Tel.: C81 3 5841 4790; fax: C81 3 5684 0634.;
e-mail: skobayas@mol.f.u-tokyo.ac.jp
0040–4020/$ - see front matter q 2005 Elsevier Ltd. All rights reserved.
doi:10.1016/j.tet.2005.08.123

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H. Miyamura et al. / Tetrahedron 61 (2005) 12177–12185
Scheme 1.
Scheme 2.
Scheme 3.
epoxide-containing copolymer (P1), which is based on
microencapsulation and cross-linking, and is successful in
immobilizing highly active, metal-based catalysts such as
palladium, platinum and scandium species.8 We applied
these methods to immobilization of dichlorotris(triphenyl-
phosphine)ruthenium (RuCl2(PPh3)3)9 and successfully
obtained an active ruthenium catalyst, so-called polymer
incarcerated ruthenium (PI-Ru) (Schemes 1–3).7
structure with many submicrometer holes was observed
(Fig. 5).
In heterogeneous catalysts, the interfacial surface area of the
catalysts is a key to obtain high activity. Recently, we have
developed a highly active Pd(0) catalyst10 having sub-
nanometer clusters and a Sc catalyst11 containing well-
regulated polymer micelles. In both cases a solvent system
While PI-Ru was found to be effective for catalytic
oxidation of alcohols and sulfides, we then decided to
investigate the structure of PI-Ru, mainly by electron
microscopy.
PI-Ru was prepared from copolymer (P1) and RuCl2(PPh3)3
in a THF-hexane system. Epoxide-containing copolymer
(P1) was dissolved in tetrahydrofuran (THF) at room
temperature, and RuCl2(PPh3)3 was added to this solution.
Transmission electron microscopic (TEM) analysis was
conducted to observe this solution, and a membrane-like
morphology without distinguishable clusters was confirmed
(Fig. 3). Hexane was then added to form microencapsulated
ruthenium (MC-Ru), which was filtered, washed and dried.
MC-Ru was next heated at 120 8C for 3.5 h to afford PI-Ru
(2). MC-Ru was observed by TEM analysis, and a spherical
structure containing some craters was observed (Fig. 4). In
addition, PI-Ru supported on a glass was observed by
scanning electron microscopy (SEM), and a membrane-like
Figure 4. TEM image of MC-Ru.
Figure 3. TEM image of a P1-RuCl2(PPh3)3 solution in THF.
Figure 5. SEM image of PI-Ru on glass.

H. Miyamura et al. / Tetrahedron 61 (2005) 12177–12185
Table 1. Solvent systems for the preparation of MC-Ru
12179
Conditions of microencapsulation
(solvent/poor solvent)
Loaded ruthenium (%)
THF/hexane
CH2Cl2/MeOH
THF–cyclohexane/hexane
90
69
89
in which the catalysts were prepared played an important
role to regulate the catalyst structure. We then examined
several solvent systems for the preparation of MC-Ru
(Table 1). In the case of a THF–hexane system, in which the
hydrophobic domains of the polymer chains should be
orientated towards the exterior, 90% of ruthenium was
loaded on the polymer support. On the other hand, in the
case of a CH2Cl2–MeOH system, in which hydrophilic
zones of the polymer chains should be orientated towards
the exterior,12 only 69% of ruthenium was loaded. These
results suggest that the ruthenium may be located in both the
hydrophilic and hydrophobic area of the polymer, but on-
balance prefer hydrophilic interactions. Therefore, we chose
the former conditions for microencapsulation, and modified
Figure 8. TEM image of MC-Ru using P1 under micelle-forming
conditions.
Figure 9. TEM image of MC-Ru using P2 under micelle-forming
conditions.
Figure 6. TEM image of a P1-RuCl2(PPh3)3 solution in THF–cyclohexane.
Figure 7. TEM image of a P2-RuCl2(PPh3)3 solution in THF–cyclohexane.
Figure 10. SEM image of P2MI-Ru on glass.

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H. Miyamura et al. / Tetrahedron 61 (2005) 12177–12185
by SEM analysis. In the case of P2, micelles were fixed
by the cross-linking and the original size of micelles
(300–2000 nm) was maintained to afford highly dispersed
3D networked morphologies (Fig. 10). On the other hand, in
the case of P1, a series of larger spherical micelles (2–4 mm)
were observed (Fig. 11). In either case, the structure is very
different from the membrane-like morphologies of PI-Ru,
which is prepared in a THF–hexane solvent system. To
distinguish these two catalysts from the original PI-Ru, they
were named polymer 1-micelle incarcerated ruthenium
(P1MI-Ru) and polymer 2-micelle incarcerated ruthenium
(P2MI-Ru). When hexane was added to the micelle
solutions, precipitates were formed and after heating at
120 8C for 3.5 h PMI-Ru was generated. In the case of
P1MI-Ru, 89% of ruthenium was loaded, same level as that
of PI-Ru prepared in THF–hexane.
We thought that the difference of the morphologies between
PI-Ru and PMI-Ru could be ascribed to the solvent systems
used in the microencapsulation. In the cases of PMI-Ru,
stable micelles were formed in THF–cyclohexane before
precipitation and the micelle morphologies were approxi-
mately maintained after cross-linking. The difference
between P1 and P2 could be ascribed to facility of phase
separation. In the case of P2, more well defined and more
stable micelles might be formed by phase separation between
the hydrophobic benzene rings and the hydrophilic epoxy or
tetraethyleneglycol moieties along the polymer backbone.10
Figure 11. SEM image of P1MI-Ru on glass.
the conditions to form micelles. Copolymer P1 or P2 (1 g),
which were effective for micelle formation in the cases of
Pd and Sc catalysts, was dissolved in THF (20 mL), and
RuCl2(PPh3)3 (400 mg) was added. Cyclohexane (60 mL)
was slowly added to this solution, and after the mixture was
stirred for 12 h at room temperature, the solution was
observed by TEM analysis. In the case of P1, spherical
capsules were not observed (Fig. 6), whilst spherical
capsules were formed in the case of P2 (Fig. 7). Next, the
solution was added to hexane and observed by TEM
analysis. In both cases, chains consisting of a series of clear
spherical micelles (100–500 nm) were formed (Figs. 8
and 9). To the mixture, glass as a support was added and the
whole mixture was allowed to stand overnight to form
precipitations of micelles on the glass. The glass support
was washed with hexane and heated at 150 8C for 5 h. After
subsequent washing with THF, the support was observed
P1MI-Ru and P2MI-Ru were first used in the oxidation of a
sulfide to compare their catalytic activities. When PI-Ru,
P1MI-Ru and P2MI-Ru were used as the catalysts, reactions
proceeded smoothly in an acetone–water co-solvent system
in the presence of 2.2 equiv of iodobenzene diacetate
(PhI(OAc)2) to afford the desired sulfone in high yields.
The reaction profile in the presence of P2MI-Ru is shown
in Figure 12. The reaction proceeded via two steps; the first
Figure 12. Reaction profile of oxidation of thioanisole in the presence of 0.5 mol% of P2MI-Ru. The yields were determined by GC analysis with reference to
an internal standard (ISZanisole). Reaction conditions: thioanisole (2 mmol), P2MI-Ru (0.5 mol%), PhI(OAc)2 (4.4 mmol), acetone (18 mL), water (2 mL)
and anisole (100 mg) at room temperature.

H. Miyamura et al. / Tetrahedron 61 (2005) 12177–12185
12181
Figure 13. Formation of phenyl–methyl sulfone in the presence of 0.5 mol% of P1MI-Ru, P2MI-Ru and PI-Ru. The yields were determined by GC analysis
with reference to an internal standard (ISZanisole). Reaction conditions: thioanisole (2 mmol), PI-Ru, P1MI-Ru or P2MI-Ru (0.5 mol%), PhI(OAc)2
(4.4 mmol), acetone (18 mL), water (2 mL) and anisole (100 mg) at room temperature.
step was oxidation of the sulfide to the sulfoxide, the
second step was oxidation of the sulfoxide to the sulfone.
Judging from the chart, it seems that the second step is
slower and that there is no induction period in the first step.
The reactions proceeded smoothly using all the three
catalysts tested as shown in Figure 13, but there are
differences in reaction rate. In the presence of 0.5 mol% of
each catalyst, the reaction was complete within 220 min in
the case of PI-Ru, 70 and 120 min in the case P1MI-Ru and
P2MI-Ru, respectively. All the catalysts could be recovered
and reused several times by simple filtration and washing
(Table 2). It is noted that no leaching of ruthenium was
observed by fluorescence X-ray (XRF) analysis. In the
cases of PI-Ru and P2MI-Ru, longer reaction times were
needed for reactions to get to complete in the 2nd use,
while in the case of P1MI-Ru the reactivity was completely
maintained for at least 4 uses. The higher activity
advantages of P1MI-Ru and P2MI-Ru compared with the
previously reported PI-Ru could be ascribed to the
formation of stable micelle morphologies with a large
surface area. Although P2MI-Ru has a larger surface area
than P1MI-Ru, P1MI-Ru has a higher catalytic activity in
the oxidation of sulfides. This could be explained by
quantity of hydrophilic parts in the polymers (21% of
hydrophilic parts in P1 vs 9% in P2). As described above,
ruthenium is mainly located in the hydrophilic parts of the
polymer, which are at the outer layer of micelles when a
THF(-cyclohexane)/hexane microencapsulation system
was employed. In the slower second step, oxidation of a
sulfoxide to a sulfone, the hydrophilic sulfoxide and
PhI(OAc)2 might be located at a hydrophilic catalytic site.
On the other hand, the generated sulfone and iodobenzene,
which are relatively hydrophobic, might be easily
eliminated from the catalytic site to the outer layer.
Therefore, in P1MI-Ru derived from P1 containing more
hydrophilic parts, there are more ruthenium metals located
in the hydrophilic parts than in P2MI-Ru, and the catalytic
turn-over frequency is also higher.
Under these conditions, aromatic (even with electron
withdrawing group), aliphatic and cyclic sulfides were
smoothly oxidized in the presence of either P1MI-Ru or
P2MI-Ru to afford the desired products in high yields
(Table 3).
Next, P1MI-Ru and P2MI-Ru were used in the oxidation of
alcohols in the presence of 2 equiv of N-methylmorpholine-
N-oxide (NMO). PI-Ru, P1MI-Ru and P2MI-Ru were
Table 2. Oxidation of a sulfide using PI-Ru and PMI-Ru
Entry
Catalyst
Yield (%)a [Time (h)b]
1st
2nd
3rd
4th
1
2
3
PI-Ru
P1MI-Ru
P2MI-Ru
quant. (2.0)
quant. (0.5)
96 (0.5)
95 (2.5)
87 (0.5)
96 (1.0)
80 (2.5)
97 (0.5)
89 (1.1)
94 (2.5)
99 (0.5)
quant. (1.3)
a Isolated yield. No peaks of ruthenium were observed by XRF analysis (!1.1%).
b Time until sulfoxide was completely consumed (confirmed by TLC).

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H. Miyamura et al. / Tetrahedron 61 (2005) 12177–12185
Table 3. Oxidation of sulfides
Table 5. Oxidation of alcohols
Entry Substrate
P1MI-Ru
P2MI-Ru
Entry
Substrate
P1MI Ru
P2MI Ru
x
Time Yield
x
Time Yield
Time
(h)
Yield
(%)a
Time
(h)
Yield
(%)a
(h)
2.5
12
(%)a
(h)
2.5
2.5
(%)a
1
2
1
1
75
1
1
93
1
2
0.5
2
quant.
98
0.5
96b
99
66
67
0.75
3
2
96
0.5
99
3
4
1
1
1
2.5
12
12
74
83
73
1
2.5
81
4
5
2
2
quant.c
quant.c
2
2
quant.c
quant.c
1
2
12
12
82
96
a Isolated yield. No peaks of ruthenium were observed by XRF analysis
(!1.1%).
5
6
1
1
12
12
50
65
1
2
1
2
12
12
12
12
45
83
60
85
b Quantitative yield, using 0.1 mol% of P2MI-Ru for 11 h.
c Determined by GC.
preliminarily treated with 20 equiv of NMO in an acetone-
isopropyl alcohol (iPrOH) (1/9) solvent at room temperature
for 12 h before application to the oxidation reactions. Both
PI-Ru and P2MI-Ru did not work well in the oxidation of
benzyl alcohol without molecular sieves 4A (MS 4A)
(Table 4, entries 1, 2). When 0.5 g/mmol of MS 4A were
added to the reaction mixture, P2MI-Ru worked well to
afford benzaldehyde in high yield (entry 5). In the cases of
PI-Ru and P1MI-Ru, the desired product was obtained in
moderate yields (entries 3, 4). P2MI-Ru could be reused
several times after recovery by simple filtration and
washing, although after 2nd use 7.5 h was needed to
complete the reaction. Lower catalyst loading of P2MI-Ru
also produced the product in high yield, albeit with
prolonged reaction time (entry 7). That P2MI-Ru was the
best catalyst for oxidation of alcohols was thought to be due
to the greater surface area as well as hydrophilicity of the
polymers that determined the reactivities in the case of
oxidation of sulfides.
a Determined by GC. No peaks of ruthenium were observed by XRF
analysis.
primary and secondary alcohols.13 Moreover, no ruthenium
leaching was observed in all cases.
3. Conclusion
In summary, we have developed a novel effective
immobilization method for ruthenium, the polymer-micelle
incarcerated (PMI) method. The solvent system for the
preparation of the catalysts was found to be very important
to the morphologies obtained. We gained an insight into the
structure of PMI-Ru by TEM and SEM analyses, the micelle
3D cross-linked networks were observed, whilst PI-Ru had
membrane-like morphologies. PMI-Ru was effective in
oxidation of sulfides and alcohols and had higher activity
than PI-Ru. Moreover, the catalyst could be recovered by
simple filtration and reused several times without loss of
catalytic activity, no Ru leaching was observed in both
systems. The higher catalytic activity of PMI-Ru was
ascribed to the greater surface area that was enabled by
well-regulated 3D network. Further investigations of other
reactions using PMI-Ru as a catalyst are now in progress.
Under these conditions, the substrate scope was surveyed
using P1MI-Ru and P2MI-Ru (Table 5). In most cases, high
to excellent yields were obtained in the oxidation of both
Table 4. Oxidation of an alcohol using PI-Ru and PMI-Ru
Entry
Catalyst
(mol%)
MS 4A
(0.5 g/mmol)
Time (h)
Yield (%)a
4. Experimental
4.1. General
1
2
3
4
5
6
7
PI-Ru (1.0)
P2MI-Ru (1.0)
PI-Ru (1.0)
P1MI-Ru (1.0)
P2MI-Ru (1.0)
P2MI-Ru (2.0)
P2MI-Ru (0.3)
K
K
C
C
C
C
C
2.5
2.5
2.5
2.5
2.5
2.5
24
47
51
59
75
93
93b
91
1H and 13C NMR spectra were recorded on a JEOL
JNM-LA300, JNM-LA400 spectrometer in CDCl3. Tetra-
methylsilane was used as an internal standard (dZ0) for 1H
NMR, and the CDCl3 solvent peak was used as the internal
standard (dZ77.0) for 13C NMR. 2-Phenylpropene,
N-bromosuccineimide (NBS), bromobenzene, glycidol,
styrene, iodobenzene diacetate and tetraethyleneglycol
a Determined by GC. No peaks of ruthenium were observed by XRF
analysis.
b 2nd; 85% for 7.5 h, 3rd; 85% for 7.5 h.

H. Miyamura et al. / Tetrahedron 61 (2005) 12177–12185
12183
were purchased from Tokyo Chemical Industry. 2-Thio-
phenemethanol, dodecanol, cyclohexanol, butyl sulfide,
tetrahydrothiophene, diphenyl sulfide, benzyl alcohol,
4-chlorophenyl methyl sulfide, thioanisole, anisole,
2-octanol and phenethyl alcohol were purchased from
Tokyo Chemical Industry and distilled before use. Di-n-bu-
tyl sulfone, dodecanal, cyclohexanone, 2-octanal, acetophe-
none and tetrahydrothiophene-1, 1-dioxide were purchased
from Tokyo Chemical Industry and distilled before use.
AIBN was purchased from Wako Pure Chemical Industry.
RuCl2(PPh3)3 was purchased from Strem Chemicals. MS
4A were purchased from Aldrich and dried in vacuo at
200 8C for 3 days. The glass used as a support was
purchased from MATSUNAMI Glass. Dry solvents (THF,
DCM, DMF) were purchased from Wako Pure Chemical
Industry. Tetraethyleneglycol mono-2-phenyl-2-propenyl
ether was prepared according to the literature.8a Dehydrated
acetone and cyclohexane were purchased from Kanto
Chemical. Hexane was purchased from Kanto Chemical
and dried over MS 3A that were purchased from Wako Pure
Chemical Industry. Water was treated by MILLIPORE
Elix-UV before use. Column chromatography was per-
formed on silica gel 60 (Merck), and preparative TLC was
carried out by using Wakogel B-5F (Wako Pure Chemical
Industry). XRF analysis was performed on Shimadzu
EDX-800 equipment. GC analysis was performed on
Shimadzu GC-17A apparatus (columnZJ & W SCIENTIFIC
DB-1). The structures of the known compounds were
confirmed by comparison with commercially available
compounds or literature data.
aqueous ammonium chloride was added to quench the
reaction, the aqueous layer was extracted with diethyl ether.
The combined organic layers were dried over sodium
sulfate, and the solvent was removed in vacuo. The residue
was purified by flash chromatography (silica, hexane/
EtOAc) to afford 2-[(2-phenylallyloxy)methyl]oxirane
1
(2.66 g, 70%). H NMR (CDCl3) dZ2.59 (dd, 1H, JZ2.7,
5.1 Hz), 2.78 (dd, 1H, JZ4.2, 5.1 Hz), 3.13–3.17 (m, 1H),
3.46 (dd, 1H, JZ5.8, 11.5 Hz), 3.77 (dd, 1H, JZ3.2,
11.5 Hz), 4.41 (ddd, 1H, JZ0.7, 1.2, 12.9 Hz), 4.48 (ddd,
1H, JZ0.5, 1.2, 12.9 Hz), 5.34–5.36 (m, 1H), 5.53–5.54 (m,
1H), 7.45–7.48 (m, 5H); 13C NMR (CDCl3) dZ44.3, 50.8,
70.5, 73.2, 114.6, 126.0, 127.8, 128.4, 138.6, 143.9; IR
(KBr) 3000, 2924, 2867, 1911, 1812, 1701, 1630, 1512,
1479, 1407, 1337, 1254, 1205, 1107, 991, 909, 839 cmK1
;
HRMS (EI): Calcd for C13H16O2 (MC), 190.0994; found,
190.0998.
4.3. Preparation of tetraethyleneglycol mono-2-phenyl-
2-propenyl ether
To sodium hydride (60% in mineral oil, 1.82 g, 45.4 mmol)
suspended in tetrahydrofuran (70 mL), tetraethyleneglycol
(8.81 mL, 45.4 mmol) was added at 0 8C. After the reaction
mixture was stirred for 1 h at room temperature, 3-chloro-
2-phenylpropene (3.46 g, 22.7 mmol) was added and the
mixture was further stirred for 12 h. The mixture was cooled
to 0 8C and diluted with diethyl ether, saturated aqueous
ammonium chloride was added to quench the reaction and
the aqueous layer was extracted with diethyl ether. The
combined organic layers were dried over sodium sulfate and
the solvent was removed in vacuo. The residue was purified
by flash chromatography to afford tetraethyleneglycol
mono-2-phenyl-2-propenyl ether (4.52 g, 64%) and tetra-
ethyleneglycol di-2-phenyl-2-propenyl ether (621 mg,
13%).
4.2. Microscopic analysis
TEM images were obtained using a JEOL JEM-1010
instrument operated at 80 kV. All TEM specimens were
prepared by placing a drop of the solution on carbon-coated
Cu grids and allowed to dry in air (without staining). SEM
images were obtained using a JEOL JSM-6700F instrument
operated at 5.0 kV. All SEM specimens were coated with
platinum for 60 s in a sputter coater (JFC-1600).
4.3.1. Tetraethyleneglycol mono-2-phenyl-2-propenyl
ether. 1H NMR (CDCl3) dZ2.72 (s, 1H), 3.58–3.74
(m, 16H), 4.42 (s, 2H), 5.34 (d, 1H, JZ1.2 Hz), 5.53
(d, 1H, JZ0.5 Hz), 7.25–7.36 (m, 3H), 7.44–7.52 (m, 2H);
13C NMR dZ61.7, 69.2, 70.3, 70.53, 70.58, 72.4, 73.1,
114.4, 126.1, 127.7, 128.3, 138.7, 144.0.
4.2.1. Preparation of vinyl monomer. 3-Bromo-
2-phenylpropene.14 A mixture of 2-phenylpropene
(22.4 g, 190 mmol), NBS (23.7 g, 133 mmol) and bromo-
benzene (76 mL) was rapidly heated in an oil bath at 160 8C
until NBS was dissolved. After cooling to room tempera-
ture, the precipitate was removed by filtration and washed
with chloroform. The filtrate was purified by distillation (bp
80–85 8C/3 mmHg) to afford 3-bromo-2-phenylpropene
containing 1-bromo-2-phenylpropene (15.5 g). The purity
was found to be 78.0% (determined by 1H NMR). 1H NMR
(CDCl3) dZ4.39 (s, 2H), 5.49 (s, 1H), 5.56(s, 1H),
7.33–7.51 (m, 5H); 13C NMR (CDCl3) dZ34.2, 117.2,
126.1, 128.3, 128.5, 137.6, 144.2.
4.3.2. Tetraethyleneglycol di-2-phenyl-2-propenyl ether.
1H NMR (CDCl3) dZ3.55–3.75 (m, 16H), 4.41 (s, 4H), 5.33
(d, 2H, JZ1.0 Hz), 5.51 (s, 2H), 7.23–7.36 (m, 6H),
7.43–7.50 (m, 4H); 13C NMR dZ69.2, 70.47, 70.51, 73.0,
114.3, 126.0, 127.6, 128.2, 138.7, 144.0.
4.4. Preparation of copolymer P1
Styrene (40.2 mL, 351 mmol), 4-vinylbenzyl glycidyl ether
(8.42 g, 43.9 mmol), tetraethyleneglycol mono-2-phenyl-
2-propenyl ether (13.6 g, 43.9 mmol) and 2,20-azobis(isobu-
tyronitrile) (393 mg) were combined in chloroform
(50.0 mL). The mixture was stirred for 24 h under reflux,
then cooled to room temperature. The resulting polymer
solution was slowly pored into cold methanol (0 8C). The
precipitated polymer was filtered and washed with methanol
several times and dried for 24 h in vacuo to afford the desired
copolymer (P1, 37.0 g). The molar ratio of the monomers was
determined by 1H NMR analysis (styrene: 4-vinylbenzyl
4.2.2. 2-[(2-Phenylallyloxy)methyl]oxirane. To sodium
hydride (60% in mineral oil, 1.6 g, 40 mmol) suspended in
dry DMF (75 mL) was added glycidol (7.4 g, 100 mmol) in
DMF (5 mL) at 0 8C. Then a solution of 3-bromo-2-
phenylpropene (78% purity, 5.05 g, 20 mmol) in DMF
(10 mL) was added at the same temperature, and the mixture
was stirred for 24 h at room temperature. After the mixture
was cooled to 0 8C and diluted with diethyl ether, saturated

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H. Miyamura et al. / Tetrahedron 61 (2005) 12177–12185
glycidyl ether: tetraethyleneglycol mono-2-phenyl-
2-propenyl etherZ79: 15: 6). Mw: 42,798, Mn: 14,649,
Mw/MnZ2.922 (gel permeation chromatography).
added, and stirred for 24 h at this temperature. Hexane
(140 mL) was slowly added to the mixture at room
temperature, coaservates were found to envelop the metal
dispersed in the medium. The mixture was left to stand at
room temperature for 12 h, the capsules were then washed
with hexane several times and dried at room temperature for
12 h, then heated at 120 8C for 3.5 h to form polymer
incarcerated ruthenium (PI-Ru, 1.12 g, 0.275 mmol/g, 72%
of ruthenium metal was loaded). The washings were
concentrated to determine loading of ruthenium metal by
fluorescence X-ray analysis.
4.5. Preparation of copolymer P2
Styrene (7.53 g, 72.3 mmol), 2-[(2-phenylallyloxy)methyl]-
oxirane (1.72 g, 9.04 mmol), tetraethyleneglycol mono-
2-phenyl-2-propenyl ether (2.81 g, 9.04 mmol) and AIBN
(105.9 mg) were combined in chloroform (11.5 mL). The
mixture was stirred for 24 h at reflux and then cooled to
room temperature. The resulting polymer solution was
slowly poured into methanol. The precipitated polymer was
filtered and washed with methanol several times and dried
for 24 h in vacuo to afford the desired copolymer (P2,
7.35 g, 61% yield). The molar ratio of the components was
4.9. PMI-Ru on glass
Copolymer (P1 or P2, 54 mg) and RuCl2(PPh3)3 (10 mg)
were dissolved in THF (1 mL), cyclohexane (3 mL) was
slowly added to this mixture to form polymer micelles. To
this solution, glass (microscope cover glass, borosilicate
glass (SiO2 64.2%, B2O 8.9%, Na2O 7.2%, ZnO 7.1%, K2O
6.4%, washed with 1 N NaOH aq./EtOH (1/1), water and
EtOH, successively, before use) was added, and the mixture
was allowed to stand overnight to precipitate the micelles
onto the glass. The glass with micelles was washed with
hexane and dried and then heated for 5 h at 150 8C. The
resulting glass was washed with THF, PMI-Ru on glass was
obtained.
1
determined by H NMR analysis (x:y:zZ91:5:4). Mw: 31
912, Mn: 19 468, Mw/MnZ1.64 (gel permeation
chromatography).
4.6. Preparation of PI-Ru
Copolymer (P1, 6.29 g) was dissolved in tetrahydrofuran
(THF, 125 mL) at room temperature, to this solution
dichlorotris(triphenylphophine)ruthenium(II) (RuCl2(PPh3),
2.52 g) was added, the mixture was stirred for 24 h at that
temperature. Hexane (800 mL) was slowly added to the
mixture at room temperature. Coaservates were found to
envelop the metal dispersed in the medium. The mixture was
left to stand at room temperature for 12 h. The resultant
capsules were washed with hexane several times and dried at
room temperature for 12 h. The capsules were then heated at
120 8C for 3.5 h to prepare polymer incarcerated ruthenium
(PI-Ru, 7.74 g, 0.302 mmol/g, 90% of ruthenium metal was
loaded). The washings were concentrated to determine
loading of ruthenium metal by fluorescence X-ray analysis.
4.10. PI-Ru on glass
Copolymer (P1, 54 mg) and RuCl2(PPh3)3 (10 mg) were
dissolved in THF (1 mL). To this solution, glass (micro-
scope cover glass, borosilicate glass (SiO2 64.2%, B2O
8.9%, Na2O 7.2%, ZnO 7.1%, K2O 6.4%, washed with 1 N
NaOH aq./EtOH (1/1), water and EtOH, successively,
before use) was added, the mixture was allowed to stand
overnight to precipitate the micelles onto the glass. The
glass with micelles was washed with hexane and dried, then
heated for 5 h at 150 8C. The resulting glass was washed
with THF, PI-Ru on glass was obtained.
4.7. Preparation of P1MI-Ru
Copolymer (P1, 1.00 g) was dissolved in tetrahydrofuran
(THF, 20 mL) at room temperature, to this solution
dichlorotris(triphenylphophine)ruthenium(II) (RuCl2(PPh3),
0.41 g) was added, after the polymer and metal were
completely dissolved, cyclohexane (60 mL) was slowly
added, and stirred for 24 h at that temperature. Hexane
(140 mL) was slowly added to the mixture at room
temperature, coaservates were found to envelop the metal
dispersed in the medium. The mixture was left to stand at
room temperature for 12 h, the resultant capsules were then
washed with hexane several times and dried at room
temperature for 12 h. The capsules were heated at 120 8C
for 3.5 h to generate polymer incarcerated ruthenium (PI-Ru,
1.16 g, 0.329 mmol/g, 89% of ruthenium metal was loaded).
The washings were concentrated to determine loading of
ruthenium metal by fluorescence X-ray analysis.
4.11. Preliminary treatment before oxidation of alcohols
i
Acetone (5.4 mL) and PrOH (0.6 mL) were added to
P1MI-Ru (0.32 g) at room temperature, and to this mixture
4-methylmorpholine N-oxide (NMO, 0.26 g) was added.
The mixture was stirred for 24 h at this temperature. The
catalyst capsules were filtered and washed with acetone
several times and dried at room temperature for 12 h to
prepare treated polymer incarcerated ruthenium (0.30 g,
0.310 mmol/g). The washings were concentrated to
determine loading of ruthenium metal by fluorescence
X-ray analysis.
4.12. A typical procedure for oxidation of sulfides
Thioanisole (120.9 mg, 0.98 mmol), PhI(OAc)2 (708.2 mg,
2.10 mmol) and P1MI-Ru (0.329 mmol/g, 31.4 mg,
1 mol%) were combined in acetone (10 mL) and water
(1.0 mL). The mixture was stirred for 30 min at room
temperature. The catalyst was collected by filtration and
washed with acetone. The crude mixture was purified by
TLC to afford methyl phenyl sulfone15 (152.2 mg,
0.98 mmol, qunat.). 1H NMR (CDCl3) dZ3.05 (s, 3H),
4.8. Preparation of P2MI-Ru
Copolymer (P2, 1.02 g) was dissolved in tetrahydrofuran
(THF, 20 mL) at room temperature, to this solution
dichlorotris(triphenylphophine)ruthenium(II) (RuCl2(PPh3),
0.41 g) was added, after the polymer and metal were
completely dissolved, cyclohexane (60 mL) was slowly

H. Miyamura et al. / Tetrahedron 61 (2005) 12177–12185
12185
7.5–8.0 (m, 5H). 13C NMR (CDCl3) dZ44.6, 127.4, 129.5,
131.0, 140.6. No leaching of Ru in the reaction mixture was
confirmed by XRF analysis. The collected catalyst was
dried and reused (2nd; 87%, 3rd; 97%, 4th; 99%).
and Catalysis; Buchmeiser, M. R., ed. Wiley-VHC:
Weinheim, Germany, 2003. (d) Kobayashi, S.; Akiyama, R.
Chem. Commun. 2003, 449–460. (e) Anastas, P. T.; Warner,
J. C. Green Chemistry: Theory and Practice; Oxford
University Press: New York, 1998.
4.12.1. Diphenyl sulfone.15 1H NMR (CDCl3) dZ
7.48–7.60 (m, 6H), 7.93–7.97 (m, 3H). 13C NMR (CDCl3)
dZ127.6, 129.3, 133.2, 141.5.
2. (a) Lee, A.; Ley, S. V. Org. Biomol. Chem. 2003, 1, 3263. (b)
Dolle, R. E. J. Comb. Chem. 2004, 6, 623–679.
3. (a) Hill, C. L. In Advances in Oxygenated Processes, Vol. 1;
JAI Press: London, 1988. (b) Hundlucky, M. Oxidations in
Organic Chemistry; American Chemical Society: Washington,
DC, 1990.
1
4.12.2. 4-Chloro methyl sulfone. H NMR (CDCl3) dZ
3.08 (s, 3H), 7.54–7.57 (m, 2H), 7.89–7.91 (m, 2H). 13C
NMR (CDCl3) dZ44.5, 129.0, 129.8, 139.1, 140.4.
4. (a) Sheldon, R.; Kochi, J. K. Metal-catalyzed Oxidations of
Organic Compounds; Academic Press: New York, 1981. (b)
Madin, A. In Comprehensive Organic Chemistry, Vol. 7;
Pergamon: Oxford, UK, 1991. (c) Parshall, G. W.; Ittel, S. D.
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5. Review: Ley, S. V.; Baxendale, I. R.; Bream, R. N.; Jackson,
P. S.; Leach, A. G.; Longbottom, D. A.; Nesi, M.; Scott, J. S.;
Storer, R. I.; Taylor, S. J. J. Chem. Soc., Perkin Trans. 1 2000,
3815–4195.
4.13. Typical procedure determining yield by GC
analysis
Di-n-butyl sulfide (142.7 mg, 0.98 mmol), PhI(OAc)2
(708.2 mg, 2.10 mmol) and P1MI-Ru (0.329 mmol/g,
31.4 mg, 1 mol%) were combined in acetone (10 mL) and
water (1.0 mL). The mixture was stirred for 2 h at room
temperature. The catalyst was collected by filtration and
washed with acetone. Yield was determined by GC analysis
with reference to an internal standard (ISZanisole). After
determining the yield, the solvents of the filtrate were
removed in vacuo, then the volume of the residue was
adjusted to 5mL using THF to give a sample for XRF
analyses for the measurement of the leaching of the
ruthenium.
6. Review: (a) Mallat, T.; Baiker, A. Chem. Rev. 2004, 104,
3037–3058. See also: (b) Yamaguchi, K.; Mori, K.; Mizugaki, T.;
Ebitani, K.; Kaneda, K. J. Am. Chem. Soc. 2000, 122,
7144–7145. (c) Yamaguchi, K.; Mizuno, N. Chem.-Eur. J.
2003, 9, 4353–4361. (d) Langer, P. J. Prakt. Chem. 2000, 342,
728–730. (e) Bleloch, A.; Johnson, B. F. G.; Ley, S. V.; Price,
A. J.; Shephard, D. S.; Thomas, A. W. Chem. Commun. 1999,
1907–1908. (f) Mori, K.; Hara, T.; Mizugaki, T.; Ebitani, K.;
Kaneda, K. J. Am. Chem. Soc. 2003, 125, 11460–11461. (g)
Motokura, K.; Nishimura, D.; Mori, K.; Mizugaki, T.; Ebitani, K.;
Kaneda, K. J. Am. Chem. Soc. 2004, 126, 5662. (h) Zhang,
Y. P.; Fei, J. H.; Yu, Y. M.; Zheng, X. M. Catal. Commun.
2004, 5, 643–646.
4.14. Typical procedure for oxidation of alcohols
Benzyl alcohol (54.0 mg, 0.5 mmol), MS 4A (250 mg),
NMO (117.0 mg, 1.0 mmol) and P2MI-Ru preliminarily
treated (0.270 mmol/g, 2 mol%) were combined in acetone/
hexaneZ1/1 (3.0 mL). After the mixture was stirred for
2.5 h under an Ar atmosphere at room temperature, the
catalyst was collected by filtration and washed with hexane
and acetone, then dried and reused. Yield was determined
by GC analysis with reference to an internal standard (ISZ
anisole). After determining the yield, the solvents of the
filtrate were removed in vacuo, then the volume of the
residue was adjusted to 5 mL using THF to give a sample for
XRF analyses for the measurement of the leaching of the
ruthenium.
7. Kobayashi, S.; Miyamura, H.; Akiyama, R.; Ishida, T. J. Am.
Chem. Soc. 2005, 127, 9251–9254.
8. (a) Akiyama, R.; Kobayashi, S. J. Am. Chem. Soc. 2003, 125,
3412–3413. (b) Okamoto, K.; Akiyama, R.; Kobayashi, S.
J. Org. Chem. 2004, 69, 2871–2873. (c) Okamoto, K.;
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(d) Akiyama, R.; Sagae, T.; Sugiura, M.; Kobayashi, S.
J. Organomet. Chem. 2004, 689, 3806–3809. (e) Hagio, H.;
Sugiura, M.; Kobayashi, S. Synlett 2005, 813–816.
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Acknowledgements
This work was partially supported by a Grant-in-Aid for
Scientific Research from Japan Society of the Promotion of
Science (JSPS).
12. The CH2Cl2–MeOH system was efficient to immobilize Pd but
inefficient to immobilize hydrophilic Sc(OTf)3.
13. We confirmed that the polymer incarcerated Ru catalyst had
higher activity than the starting RuCl2(PPh3)3. For an
application of the Ru catalyst to a flow system, see Ref. 7.
14. (a) Reed, S. F., Jr. J. Org. Chem. 1965, 30, 3258. (b) Vaccher,
C.; Berthelot, P.; Flouquet, N.; Vaccher, M.-P.; Debaert, M.
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