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postgraduate thesis: Ruthenium porphyrin catalyzed nitrene insertion into C-H bonds of aromatic heterocycles, aldehydes and alkanes

TitleRuthenium porphyrin catalyzed nitrene insertion into C-H bonds of aromatic heterocycles, aldehydes and alkanes
Authors
Advisors
Advisor(s):Che, CM
Issue Date2012
PublisherThe University of Hong Kong (Pokfulam, Hong Kong)
Citation
Xiao, W. [萧文博]. (2012). Ruthenium porphyrin catalyzed nitrene insertion into C-H bonds of aromatic heterocycles, aldehydes and alkanes. (Thesis). University of Hong Kong, Pokfulam, Hong Kong SAR. Retrieved from http://dx.doi.org/10.5353/th_b5043431
AbstractTransition metal catalyzed selective nitrene insertion into C-H bonds, which allows direct incorporation of nitrogen functionality into hydrocarbons, represents an appealing methodology for C-N bond formation, a type of bond formation of great importance in organic synthesis due to the prevalence of amino groups in biologically active natural products and pharmaceuticals. Organic azides are atom-economic and an environment-benign nitrene source. This dissertation reports the use of organic azides as a nitrene source to develop a series of protocols for C-H bond functionalization by metal-catalyzed nitrene insertion, including the diimination of indoles, the phosphoramidation of aldehydes and the amination of hydrocarbons catalyzed by ruthenium porphyrins. Carbonylruthenium(II) porphyrin complex Ru(TTP)(CO) (TTP = meso-tetrakis(p-tolyl)porphyrinato dianion) is an effective catalyst for nitrene transfer to sp2 C-H bonds of indoles using aryl azides (ArN3) as a nitrene source. This “Ru(TTP)(CO) + ArN3” protocol selectively results in the diimination of indoles without the corresponding monoimination products being detected. In the presence of a catalyst Ru(TTP)(CO), the reactions of N-methylindole with ArN3 (Ar = 4-nitrophenyl; 3,5-bis(trifluoromethyl)phenyl), and reactions of a variety of N-substituted indoles with 4-nitrophenylazide, afford 2,3-diiminoindoles in good to excellent yields (up to 90%). This unique type of 2,3-diimination products was characterized by NMR spectroscopy, mass spectrometry and single crystal X-ray crystallography. The catalytic diimination product from N-methylindole and ArN3 (Ar = 3,5-bis(trifluoromethyl)phenyl) can also be obtained through stoichiometric reaction of N-methylindole with the corresponding bis(arylimido)ruthenium(VI) porphyrin, suggesting the possible involvement of RuVI(TTP)(NAr)2 intermediates in the Ru(TTP)(CO)-catalyzed diimination reactions. Dichlororuthenium(IV) porphyrin complex Ru(TTP)Cl2 efficiently catalyzes the phosphoramidation of aldehydes with phosphoryl azides (RO)2P(O)N3 via a nitrene insertion into sp2 C-H bonds of aldehydes. This represents the first study on the catalytic activity of a ruthenium(IV) porphyrin towards nitrene insertion into C-H bonds. The “Ru(TTP)Cl2 + (RO)2P(O)N3” protocol exhibits high chemoselectivity and functional group tolerability. Good to excellent product yields (up to 99%) have been obtained for the Ru(TTP)Cl2-catalyzed phosphoramidation of a wide variety of aldehydes with commercially available (PhO)2P(O)N3 (DPPA) and phosphoramidation of p-tolualdehyde with various (RO)2P(O)N3 (R = Me, Et, CCl3CH2, 4-nitrophenyl). The reaction can be scaled up by adding phosphoryl azide dropwise. The use of commercially available DPPA in this protocol offers a convenient and practical method for the synthesis of N-acylphosphoramidates. “Ru(TDCPP)Cl2 + (CCl3CH2O)2P(O)N3” (TDCPP = meso-tetrakis(2,6-dichlorophenyl)porphyrinato dianion) serves as an effective protocol for intermolecular nitrene insertion into sp3 C-H bonds of hydrocarbons. Using this protocol, a variety of hydrocarbons including cycloalkanes (such as cyclohexane) and ethylbenzenes undergo sp3 C-H amination in moderate to high yields (up to 86%). Compared with ruthenium(II) porphyrins such as Ru(TDCPP)(CO) and dirhodium carboxylates such as Rh2(OAc)4, Ru(TDCPP)Cl2 displays a markedly higher catalytic activity towards the nitrene sp3 C-H insertion with (CCl3CH2O)2P(O)N3. In addition, intramolecular nitrene insertion into sp3 C-H bond can also take place in good yields with Ru(TDCPP)Cl2 as the catalyst.
DegreeDoctor of Philosophy
SubjectHydrocarbons.
Azides.
Ruthenium compounds.
Porphyrins.
Catalysts.
Nitrenes.
Dept/ProgramChemistry
Persistent Identifierhttp://hdl.handle.net/10722/184244

 

DC FieldValueLanguage
dc.contributor.advisorChe, CM-
dc.contributor.authorXiao, Wenbo.-
dc.contributor.author萧文博.-
dc.date.accessioned2013-06-29T15:45:54Z-
dc.date.available2013-06-29T15:45:54Z-
dc.date.issued2012-
dc.identifier.citationXiao, W. [萧文博]. (2012). Ruthenium porphyrin catalyzed nitrene insertion into C-H bonds of aromatic heterocycles, aldehydes and alkanes. (Thesis). University of Hong Kong, Pokfulam, Hong Kong SAR. Retrieved from http://dx.doi.org/10.5353/th_b5043431-
dc.identifier.urihttp://hdl.handle.net/10722/184244-
dc.description.abstractTransition metal catalyzed selective nitrene insertion into C-H bonds, which allows direct incorporation of nitrogen functionality into hydrocarbons, represents an appealing methodology for C-N bond formation, a type of bond formation of great importance in organic synthesis due to the prevalence of amino groups in biologically active natural products and pharmaceuticals. Organic azides are atom-economic and an environment-benign nitrene source. This dissertation reports the use of organic azides as a nitrene source to develop a series of protocols for C-H bond functionalization by metal-catalyzed nitrene insertion, including the diimination of indoles, the phosphoramidation of aldehydes and the amination of hydrocarbons catalyzed by ruthenium porphyrins. Carbonylruthenium(II) porphyrin complex Ru(TTP)(CO) (TTP = meso-tetrakis(p-tolyl)porphyrinato dianion) is an effective catalyst for nitrene transfer to sp2 C-H bonds of indoles using aryl azides (ArN3) as a nitrene source. This “Ru(TTP)(CO) + ArN3” protocol selectively results in the diimination of indoles without the corresponding monoimination products being detected. In the presence of a catalyst Ru(TTP)(CO), the reactions of N-methylindole with ArN3 (Ar = 4-nitrophenyl; 3,5-bis(trifluoromethyl)phenyl), and reactions of a variety of N-substituted indoles with 4-nitrophenylazide, afford 2,3-diiminoindoles in good to excellent yields (up to 90%). This unique type of 2,3-diimination products was characterized by NMR spectroscopy, mass spectrometry and single crystal X-ray crystallography. The catalytic diimination product from N-methylindole and ArN3 (Ar = 3,5-bis(trifluoromethyl)phenyl) can also be obtained through stoichiometric reaction of N-methylindole with the corresponding bis(arylimido)ruthenium(VI) porphyrin, suggesting the possible involvement of RuVI(TTP)(NAr)2 intermediates in the Ru(TTP)(CO)-catalyzed diimination reactions. Dichlororuthenium(IV) porphyrin complex Ru(TTP)Cl2 efficiently catalyzes the phosphoramidation of aldehydes with phosphoryl azides (RO)2P(O)N3 via a nitrene insertion into sp2 C-H bonds of aldehydes. This represents the first study on the catalytic activity of a ruthenium(IV) porphyrin towards nitrene insertion into C-H bonds. The “Ru(TTP)Cl2 + (RO)2P(O)N3” protocol exhibits high chemoselectivity and functional group tolerability. Good to excellent product yields (up to 99%) have been obtained for the Ru(TTP)Cl2-catalyzed phosphoramidation of a wide variety of aldehydes with commercially available (PhO)2P(O)N3 (DPPA) and phosphoramidation of p-tolualdehyde with various (RO)2P(O)N3 (R = Me, Et, CCl3CH2, 4-nitrophenyl). The reaction can be scaled up by adding phosphoryl azide dropwise. The use of commercially available DPPA in this protocol offers a convenient and practical method for the synthesis of N-acylphosphoramidates. “Ru(TDCPP)Cl2 + (CCl3CH2O)2P(O)N3” (TDCPP = meso-tetrakis(2,6-dichlorophenyl)porphyrinato dianion) serves as an effective protocol for intermolecular nitrene insertion into sp3 C-H bonds of hydrocarbons. Using this protocol, a variety of hydrocarbons including cycloalkanes (such as cyclohexane) and ethylbenzenes undergo sp3 C-H amination in moderate to high yields (up to 86%). Compared with ruthenium(II) porphyrins such as Ru(TDCPP)(CO) and dirhodium carboxylates such as Rh2(OAc)4, Ru(TDCPP)Cl2 displays a markedly higher catalytic activity towards the nitrene sp3 C-H insertion with (CCl3CH2O)2P(O)N3. In addition, intramolecular nitrene insertion into sp3 C-H bond can also take place in good yields with Ru(TDCPP)Cl2 as the catalyst.-
dc.languageeng-
dc.publisherThe University of Hong Kong (Pokfulam, Hong Kong)-
dc.relation.ispartofHKU Theses Online (HKUTO)-
dc.rightsThe author retains all proprietary rights, (such as patent rights) and the right to use in future works.-
dc.rightsCreative Commons: Attribution 3.0 Hong Kong License-
dc.source.urihttp://hub.hku.hk/bib/B50434317-
dc.subject.lcshHydrocarbons.-
dc.subject.lcshAzides.-
dc.subject.lcshRuthenium compounds.-
dc.subject.lcshPorphyrins.-
dc.subject.lcshCatalysts.-
dc.subject.lcshNitrenes.-
dc.titleRuthenium porphyrin catalyzed nitrene insertion into C-H bonds of aromatic heterocycles, aldehydes and alkanes-
dc.typePG_Thesis-
dc.identifier.hkulb5043431-
dc.description.thesisnameDoctor of Philosophy-
dc.description.thesislevelDoctoral-
dc.description.thesisdisciplineChemistry-
dc.description.naturepublished_or_final_version-
dc.identifier.doi10.5353/th_b5043431-
dc.date.hkucongregation2013-

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