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Article: Highly efficient asymmetric epoxidation of alkenes with a D4-symmetric chiral dichlororuthenium(IV) porphyrin catalyst

TitleHighly efficient asymmetric epoxidation of alkenes with a D4-symmetric chiral dichlororuthenium(IV) porphyrin catalyst
Authors
Issue Date2001
PublisherAmerican 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?
AbstractA 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 Identifierhttp://hdl.handle.net/10722/167722
ISSN
2015 Impact Factor: 4.785
2015 SCImago Journal Rankings: 2.095
ISI Accession Number ID
References

 

DC FieldValueLanguage
dc.contributor.authorZhang, Ren_US
dc.contributor.authorYu, WYen_US
dc.contributor.authorWong, KYen_US
dc.contributor.authorChe, CMen_US
dc.date.accessioned2012-10-08T03:10:27Z-
dc.date.available2012-10-08T03:10:27Z-
dc.date.issued2001en_US
dc.identifier.citationJournal Of Organic Chemistry, 2001, v. 66 n. 24, p. 8145-8153en_US
dc.identifier.issn0022-3263en_US
dc.identifier.urihttp://hdl.handle.net/10722/167722-
dc.description.abstractA 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.languageengen_US
dc.publisherAmerican Chemical Society. The Journal's web site is located at http://pubs.acs.org/jocen_US
dc.relation.ispartofJournal of Organic Chemistryen_US
dc.subject.meshAlkenes - Chemistryen_US
dc.subject.meshCatalysisen_US
dc.subject.meshChlorineen_US
dc.subject.meshEpoxy Compounds - Chemical Synthesisen_US
dc.subject.meshMetalloporphyrins - Chemistryen_US
dc.subject.meshOxidation-Reductionen_US
dc.subject.meshRuthenium Compounds - Chemistryen_US
dc.subject.meshStereoisomerismen_US
dc.titleHighly efficient asymmetric epoxidation of alkenes with a D4-symmetric chiral dichlororuthenium(IV) porphyrin catalysten_US
dc.typeArticleen_US
dc.identifier.emailChe, CM:cmche@hku.hken_US
dc.identifier.authorityChe, CM=rp00670en_US
dc.description.naturelink_to_subscribed_fulltexten_US
dc.identifier.doi10.1021/jo010329ien_US
dc.identifier.pmid11722218-
dc.identifier.scopuseid_2-s2.0-0035977238en_US
dc.identifier.hkuros72378-
dc.relation.referenceshttp://www.scopus.com/mlt/select.url?eid=2-s2.0-0035977238&selection=ref&src=s&origin=recordpageen_US
dc.identifier.volume66en_US
dc.identifier.issue24en_US
dc.identifier.spage8145en_US
dc.identifier.epage8153en_US
dc.identifier.isiWOS:000172489500031-
dc.publisher.placeUnited Statesen_US
dc.identifier.scopusauthoridZhang, R=7404865969en_US
dc.identifier.scopusauthoridYu, WY=7403913673en_US
dc.identifier.scopusauthoridWong, KY=7404760030en_US
dc.identifier.scopusauthoridChe, CM=7102442791en_US

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