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Article: Stoichiometric enantioselective alkene epoxidation with a chiral dioxoruthenium(VI) D4-porphyrinato complex

TitleStoichiometric enantioselective alkene epoxidation with a chiral dioxoruthenium(VI) D4-porphyrinato complex
Authors
Issue Date1998
PublisherRoyal Society of Chemistry. The Journal's web site is located at http://www.rsc.org/dalton
Citation
Journal Of The Chemical Society - Dalton Transactions, 1998 n. 21, p. 3559-3564 How to Cite?
AbstractA dioxoruthenium(VI) complex containing a D4-porphyrinato ligand por* {H2por* = 5,10,15,20-tetrakis-[(1S,4R,5R,8S)-1,2,3,4,5,6,7,8-octahydro-1,4:5,8- dimethanoanthracen-9-yl]porphyrin} has been prepared by oxidation of its ruthenium(II) carbonyl precursor with m-chloroperoxybenzoic acid and characterised by spectroscopic methods. The [RuVI(por*)O2] complex undergoes enantioselective epoxidation of alkenes and the highest enantiomeric excess (ee) attainable is 77%. In the presence of pyrazole the complex transforms to [RuIV(por*)(pz)2] when reacting with alkenes. The kinetics of the epoxidation of para-substituted styrenes has been studied. The experimental rate law is - d[RuVI]/dt = k2[RuVI][alkene]. The second order rate constants k2 at 25°C fall in a narrow range, 2.1 × 10-3-9.7 × 10-3 dm3 mol-1 s-1. Comparison of the Hammett plot (log krel vs. σ*) with those for achiral analogues [RuVI(tpp)O2] (H2tpp = 5,10,15,20-tetraphenylporphyrin) and [RuVI(oep)O2] (H2oep = 2,3,7,8,12,13,17,18-octaethylporphyrin) suggests the formation of a radical intermediate for the alkene epoxidations. Both [RuII(por*)(CO)(EtOH)] and [RuVI(por*)O2] were examined for enantioselective catalysis. Enantioselectivities of the stoichiometric and catalytic reactions showed good correlation. There is no solvent dependence on enantioselectivity when changing the solvent from dichloromethane to benzene.
Persistent Identifierhttp://hdl.handle.net/10722/69817
ISSN
1999 Impact Factor: 2.31
ISI Accession Number ID
References

 

DC FieldValueLanguage
dc.contributor.authorLai, TSen_HK
dc.contributor.authorKwong, HLen_HK
dc.contributor.authorZhang, Ren_HK
dc.contributor.authorChe, CMen_HK
dc.date.accessioned2010-09-06T06:17:06Z-
dc.date.available2010-09-06T06:17:06Z-
dc.date.issued1998en_HK
dc.identifier.citationJournal Of The Chemical Society - Dalton Transactions, 1998 n. 21, p. 3559-3564en_HK
dc.identifier.issn0300-9246en_HK
dc.identifier.urihttp://hdl.handle.net/10722/69817-
dc.description.abstractA dioxoruthenium(VI) complex containing a D4-porphyrinato ligand por* {H2por* = 5,10,15,20-tetrakis-[(1S,4R,5R,8S)-1,2,3,4,5,6,7,8-octahydro-1,4:5,8- dimethanoanthracen-9-yl]porphyrin} has been prepared by oxidation of its ruthenium(II) carbonyl precursor with m-chloroperoxybenzoic acid and characterised by spectroscopic methods. The [RuVI(por*)O2] complex undergoes enantioselective epoxidation of alkenes and the highest enantiomeric excess (ee) attainable is 77%. In the presence of pyrazole the complex transforms to [RuIV(por*)(pz)2] when reacting with alkenes. The kinetics of the epoxidation of para-substituted styrenes has been studied. The experimental rate law is - d[RuVI]/dt = k2[RuVI][alkene]. The second order rate constants k2 at 25°C fall in a narrow range, 2.1 × 10-3-9.7 × 10-3 dm3 mol-1 s-1. Comparison of the Hammett plot (log krel vs. σ*) with those for achiral analogues [RuVI(tpp)O2] (H2tpp = 5,10,15,20-tetraphenylporphyrin) and [RuVI(oep)O2] (H2oep = 2,3,7,8,12,13,17,18-octaethylporphyrin) suggests the formation of a radical intermediate for the alkene epoxidations. Both [RuII(por*)(CO)(EtOH)] and [RuVI(por*)O2] were examined for enantioselective catalysis. Enantioselectivities of the stoichiometric and catalytic reactions showed good correlation. There is no solvent dependence on enantioselectivity when changing the solvent from dichloromethane to benzene.en_HK
dc.languageengen_HK
dc.publisherRoyal Society of Chemistry. The Journal's web site is located at http://www.rsc.org/daltonen_HK
dc.relation.ispartofJournal of the Chemical Society - Dalton Transactionsen_HK
dc.titleStoichiometric enantioselective alkene epoxidation with a chiral dioxoruthenium(VI) D4-porphyrinato complexen_HK
dc.typeArticleen_HK
dc.identifier.openurlhttp://library.hku.hk:4550/resserv?sid=HKU:IR&issn=1472-7773&volume=&spage=3559&epage=3564&date=1998&atitle=Stoichiometric+enantioselective+alkene+epoxidation+with+a+chiral+dioxoruthenium+(VI)+D4-porphyrinato+complexen_HK
dc.identifier.emailChe, CM:cmche@hku.hken_HK
dc.identifier.authorityChe, CM=rp00670en_HK
dc.description.naturelink_to_subscribed_fulltext-
dc.identifier.doi10.1039/A802587H-
dc.identifier.scopuseid_2-s2.0-33748463018en_HK
dc.identifier.hkuros40283en_HK
dc.relation.referenceshttp://www.scopus.com/mlt/select.url?eid=2-s2.0-33748463018&selection=ref&src=s&origin=recordpageen_HK
dc.identifier.issue21en_HK
dc.identifier.spage3559en_HK
dc.identifier.epage3564en_HK
dc.identifier.isiWOS:000077185600005-
dc.identifier.scopusauthoridLai, TS=7202203490en_HK
dc.identifier.scopusauthoridKwong, HL=35569416300en_HK
dc.identifier.scopusauthoridZhang, R=7404865969en_HK
dc.identifier.scopusauthoridChe, CM=7102442791en_HK

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