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Article: Highly efficient asymmetric epoxidation of alkenes with a D4-symmetric chiral dichlororuthenium(IV) porphyrin catalyst
Title | Highly efficient asymmetric epoxidation of alkenes with a D4-symmetric chiral dichlororuthenium(IV) porphyrin catalyst |
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Authors | |
Issue Date | 2001 |
Publisher | American Chemical Society. The Journal's web site is located at http://pubs.acs.org/joc |
Citation | Journal Of Organic Chemistry, 2001, v. 66 n. 24, p. 8145-8153 How to Cite? |
Abstract | A dichlororuthenium(IV) complex of 5,10,15,20-tetrakis[(1S,4R,5R,8S)-1,2,3,4,5,6,7,8-octahydro-1,2: 5,8-dimethanoanthrance-9-yl] porphyrin, [Ru IV(D4-Por*)Cl 2] (1), was prepared by heating [Ru II-(D4-Por*)(CO)(MeOH)] (2) in refluxing CCl 4. Complex 1 is characterized by 1H NMR (paramagnetically shifted pyrrolic protons at δ H = -52.3 ppm), FAB-mass spectroscopies, and magnetic susceptibility measurement (μ eff = 3.1 μ B). The ruthenium complex exhibits remarkable catalytic activity toward enantioselective alkene epoxidation using 2,6-dichloropyridine N-oxide (Cl 2pyNO) as terminal oxidant. The Ru(IV)-catalyzed styrene epoxidation is achieved within 2 h (versus 48 h for the 2-catalyzed reaction), and optically active styrene oxide was obtained in 69% ee and 84% yield (875 turnovers). Likewise, substituted styrenes and some conjugated cis-disubstituted alkenes (e.g., cis-β-methylstyrene, cis-1-phenyl-3-penten-1-yne, 1,2-dihydronaphthalene, and 2,2-dimethylchromenes) are converted effectively to their organic epoxides in 50-80% ee under the Ru(IV)-catalyzed conditions, and more than 850 turnovers of epoxides have been attained. When subjecting 1 to four repetitive uses by recharging the reaction mixture with Cl 2pyNO and styrene, styrene oxide was obtained in a total of 2190 turnovers and 69% ee. UV - vis and ESI-mass spectral analysis of the final reaction mixture revealed that a ruthenium - carbonyl species could have been formed during the catalytic reaction, leading to the apparent catalyst deactivation. We prepared a heterogeneous chiral ruthenium porphyrin catalyst by immobilizing 1 into sol - gel matrix. The heterogeneous catalystis highly active toward asymmetric styrene epoxidation producing styrene oxide in 69% ee with up to 10 800 turnovers being achieved. The loss of activity of the Ru/sol - gel catalyst is ascribed to catalyst leaching and/or deactivation. On the basis of Hammett correlation (ρ + = -1.62, R = 0.99) and product analysis, a dioxoruthenium(VI) porphyrin intermediate is not favored. |
Persistent Identifier | http://hdl.handle.net/10722/167722 |
ISSN | 2023 Impact Factor: 3.3 2023 SCImago Journal Rankings: 0.724 |
ISI Accession Number ID | |
References |
DC Field | Value | Language |
---|---|---|
dc.contributor.author | Zhang, R | en_US |
dc.contributor.author | Yu, WY | en_US |
dc.contributor.author | Wong, KY | en_US |
dc.contributor.author | Che, CM | en_US |
dc.date.accessioned | 2012-10-08T03:10:27Z | - |
dc.date.available | 2012-10-08T03:10:27Z | - |
dc.date.issued | 2001 | en_US |
dc.identifier.citation | Journal Of Organic Chemistry, 2001, v. 66 n. 24, p. 8145-8153 | en_US |
dc.identifier.issn | 0022-3263 | en_US |
dc.identifier.uri | http://hdl.handle.net/10722/167722 | - |
dc.description.abstract | A dichlororuthenium(IV) complex of 5,10,15,20-tetrakis[(1S,4R,5R,8S)-1,2,3,4,5,6,7,8-octahydro-1,2: 5,8-dimethanoanthrance-9-yl] porphyrin, [Ru IV(D4-Por*)Cl 2] (1), was prepared by heating [Ru II-(D4-Por*)(CO)(MeOH)] (2) in refluxing CCl 4. Complex 1 is characterized by 1H NMR (paramagnetically shifted pyrrolic protons at δ H = -52.3 ppm), FAB-mass spectroscopies, and magnetic susceptibility measurement (μ eff = 3.1 μ B). The ruthenium complex exhibits remarkable catalytic activity toward enantioselective alkene epoxidation using 2,6-dichloropyridine N-oxide (Cl 2pyNO) as terminal oxidant. The Ru(IV)-catalyzed styrene epoxidation is achieved within 2 h (versus 48 h for the 2-catalyzed reaction), and optically active styrene oxide was obtained in 69% ee and 84% yield (875 turnovers). Likewise, substituted styrenes and some conjugated cis-disubstituted alkenes (e.g., cis-β-methylstyrene, cis-1-phenyl-3-penten-1-yne, 1,2-dihydronaphthalene, and 2,2-dimethylchromenes) are converted effectively to their organic epoxides in 50-80% ee under the Ru(IV)-catalyzed conditions, and more than 850 turnovers of epoxides have been attained. When subjecting 1 to four repetitive uses by recharging the reaction mixture with Cl 2pyNO and styrene, styrene oxide was obtained in a total of 2190 turnovers and 69% ee. UV - vis and ESI-mass spectral analysis of the final reaction mixture revealed that a ruthenium - carbonyl species could have been formed during the catalytic reaction, leading to the apparent catalyst deactivation. We prepared a heterogeneous chiral ruthenium porphyrin catalyst by immobilizing 1 into sol - gel matrix. The heterogeneous catalystis highly active toward asymmetric styrene epoxidation producing styrene oxide in 69% ee with up to 10 800 turnovers being achieved. The loss of activity of the Ru/sol - gel catalyst is ascribed to catalyst leaching and/or deactivation. On the basis of Hammett correlation (ρ + = -1.62, R = 0.99) and product analysis, a dioxoruthenium(VI) porphyrin intermediate is not favored. | en_US |
dc.language | eng | en_US |
dc.publisher | American Chemical Society. The Journal's web site is located at http://pubs.acs.org/joc | en_US |
dc.relation.ispartof | Journal of Organic Chemistry | en_US |
dc.subject.mesh | Alkenes - Chemistry | en_US |
dc.subject.mesh | Catalysis | en_US |
dc.subject.mesh | Chlorine | en_US |
dc.subject.mesh | Epoxy Compounds - Chemical Synthesis | en_US |
dc.subject.mesh | Metalloporphyrins - Chemistry | en_US |
dc.subject.mesh | Oxidation-Reduction | en_US |
dc.subject.mesh | Ruthenium Compounds - Chemistry | en_US |
dc.subject.mesh | Stereoisomerism | en_US |
dc.title | Highly efficient asymmetric epoxidation of alkenes with a D4-symmetric chiral dichlororuthenium(IV) porphyrin catalyst | en_US |
dc.type | Article | en_US |
dc.identifier.email | Che, CM:cmche@hku.hk | en_US |
dc.identifier.authority | Che, CM=rp00670 | en_US |
dc.description.nature | link_to_subscribed_fulltext | en_US |
dc.identifier.doi | 10.1021/jo010329i | en_US |
dc.identifier.pmid | 11722218 | - |
dc.identifier.scopus | eid_2-s2.0-0035977238 | en_US |
dc.identifier.hkuros | 72378 | - |
dc.relation.references | http://www.scopus.com/mlt/select.url?eid=2-s2.0-0035977238&selection=ref&src=s&origin=recordpage | en_US |
dc.identifier.volume | 66 | en_US |
dc.identifier.issue | 24 | en_US |
dc.identifier.spage | 8145 | en_US |
dc.identifier.epage | 8153 | en_US |
dc.identifier.isi | WOS:000172489500031 | - |
dc.publisher.place | United States | en_US |
dc.identifier.scopusauthorid | Zhang, R=7404865969 | en_US |
dc.identifier.scopusauthorid | Yu, WY=7403913673 | en_US |
dc.identifier.scopusauthorid | Wong, KY=7404760030 | en_US |
dc.identifier.scopusauthorid | Che, CM=7102442791 | en_US |
dc.identifier.issnl | 0022-3263 | - |