Dihydroxylation of Olefins
Catalyzed by Polystyrene-sg-imidazolium
Resin-Supported Osmium Complex
Bong-Hyun Juna, Jong-Ho Kima,1, Juyoung Parka, Homan Kangb, Sang-Hyeup Lee*c, Yoon-Sik Lee*a,b a School of Chemical and Biological Engineering, Seoul National University, Seoul 151-744,
Korea Fax: +82(2)8769625; e-Mail: yslee@snu.ac.kr; b Interdisciplinary Program in Nano-Science and
Technology, Seoul National University, Seoul 151-747, Korea c Department of Life Chemistry, Catholic University of Daegu, Gyeongsan
712-702, Korea
Further Information
Publication History
Received
24 April 2008 Publication Date: 21 August 2008 (online)
Osmium tetroxide was immobilized onto an imidazolium-based polymer,
poly(1-methylimidazoliummethyl styrene)-surface grafted-PS (PS-sg-IM) resin. In order to characterize
the polymer-imidazolium-supported osmium-complex catalysts,
Fourier transform infrared (FT-IR) spectroscopy, field emission
scanning electron microscopy (FE-SEM), energy dispersive X-ray microanalysis
(EDX), and inductively coupled plasma-atomic emission spectroscopy
(ICP-AES) experiments were carried out, and we verified that the
formation of the osmium complex occurred only on the surface of
the polymer support. This polymer catalysts was used in the dihydroxylation
of various olefins, revealed excellent catalytic activity, and could
be reused up to three times
Key words
osmium - imidazolium - heterogeneous catalysis
References and Notes
2aJohnson RA.
Sharpless KB. In
Catalytic Asymmetric Synthesis
2nd
ed.:
Ojima I.
VCH;
Weinheim:
2000.
p.357
Preparation of
Polystyrene-Surface-Grafted Imidazolium Resin-Supported Osmium (PS-sg-IM Os) Complex
Poly(1-methylimidazolium-methyl
styrene)-g-PS Resin (PS-sg-IM) was prepared
following our published protocol.
[¹³]
The
PS-sg-IM (100 mg, 0.37 mmol/g,
0.031 mmol) and K2OsO4˙2H2O
(8.6 mg, 0.023 mmol, 0.6 equiv) were mixed and stirred in a mixture
of H2O (1.2 mL) at 25 ˚C for 2 d. The
resulting resin was filtered and washed vigorously with distilled
H2O (5 × 10 mL), acetone (5 × 10 mL),
and MeOH (5 × 10 mL). The resin was then dried in vacuo
overnight to generate the polystyrene-sg-imidazolium resin-supported
osmium (PS-sg-IM Os) complex (PS-sg-IM Os). The loading level of osmium
on the polystyrene-imidazolium-based polymer was 0.178
mmol/g, which was analyzed by ICP-AES.
Typical Experimental
Procedure for Dihydroxylation of Olefins Using PS-sg-IM Os PS-sg-IM Os (56 mg, 1 mol% Os,
0.18 mmol-Os/g) was suspended in H2O-acetone
(v/v, 1:3, 3 mL). To this suspension was added the olefin
(1 mmol) and NMO (152 mg, 1.3 mmol), and the reaction mixture was
agitated in a shaking incubator at 25 ˚C in an
air atmosphere. The progress of the reaction was monitored by TLC.
After consumption of the starting olefin, the resulting reaction mixture
was filtered through polyethylene frit and washed with MeOH (5 × 10
mL). The combined filtrate was evaporated, and the resulting residue
was purified by flash chromatography on SiO2 to afford
the desired dihydroxylated product. All the products were characterized by ¹H
NMR spectroscopy andGC-MS. All the dihydroxylated products are known,
and their spectral data were in accordance with those reported in
the literature.
[9]
Reusability Test
of PS-sg-IM
Os The DH reaction was performed at exactly the same
scale using α-methylstyrene as a model substrate following
the typical experimental procedure described above. After the consumption
of α-methylstyrene (TLC), the mixture was filtered through
polyethylene frit and washed with MeOH (5 × 10 mL). The
dihydroxyated product was isolated from the combined filtrate by
the method described in the previous section. The recovered catalyst
was collected on the polyethylene frit, dried under a nitrogen stream,
transferred back to the reaction flask, and was then reused two
more times for the same reaction.
