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Kouki Matsubara - One of the best experts on this subject based on the ideXlab platform.
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highly efficient catalytic reactions via activation of a si h bond of organohydrosilanes by triruthenium carbonyl clusters bearing bridging an Acenaphthylene or azulene ligand
Journal of Synthetic Organic Chemistry Japan, 2005Co-Authors: Kouki Matsubara, Hideo NagashimaAbstract:Highly efficient catalytic reactions have been achieved via activation of Si-H bonds of organohydrosilanes by triruthenium carbonyl clusters bearing bridging Acenaphthylene or azulene ligands. A ruthenium complex, (μ2, η2:η3:η5-Acenaphthylene) Ru3 (CO)7 (1) catalyzes hydrosilylation of ketones and aldehydes in solution at room temperature to form the corresponding silyl ether in high yields. Prior activation of the catalyst by excess amounts of the hydrosilane results in dramatic increase of the catalytic activity. Application of the hydrosilylation catalyzed by preactivated 1 to the reduction of carboxylic acids and their derivatives has provided efficient preparative methods for silyl and alkyl ethers from esters, silyl ethers from carboxylic acids, and amines from amides, which are hardly achieved with other transition metal catalysts. The cluster 1 also behaves as an active catalyst for ring-opening polymerization of cyclic ethers and cyclic siloxanes and addition polymerization of vinyl ethers, which are induced by hydrosilanes. Spectroscopic analysis of the polymers obtained reveals existence of an organosilyl moiety at the end group, which is useful for further chemical transformation of the formed polymer. Isolation, characterization, and reactions of possible catalytically active species help discussion on the reaction mechanisms, in which a triruthenium hydridosilyl cluster is involved in the catalytic cycle.
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silane induced polymerization of vinyl ethers catalyzed by a triruthenium carbonyl cluster μ3 η2 η3 η5 Acenaphthylene ru3 co 7
Organometallics, 2004Co-Authors: Hideo Nagashima, Chikara Itonaga, Jushiro Yasuhara, Yukihiro Motoyama, Kouki MatsubaraAbstract:The polymerization of vinyl ethers (CH2CHOR, R = nBu, iBu, tBu, iPr) is catalyzed by a ruthenium cluster, (μ3,η2:η3:η5-Acenaphthylene)Ru3(CO)7 (1), using several hydrosilanes as the initiator to gi...
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a triruthenium carbonyl cluster bearing a bridging Acenaphthylene ligand an efficient catalyst for reduction of esters carboxylic acids and amides by trialkylsilanes
ChemInform, 2002Co-Authors: Kouki Matsubara, Takafumi Iura, Tomoyuki Maki, Hideo NagashimaAbstract:An efficient reduction of carboxylic acids, esters, and amides with trialkylsilanes is accomplished using a triruthenium carbonyl cluster bearing a bridging Acenaphthylene ligand, (μ3,η2:η3:η5-Acenaphthylene)Ru3(CO)7, as the catalyst. Preactivation of the catalyst by hydrosilanes accelerates the reactions. Sterically small trialkylsilanes are effective in these reactions. Reduction of carboxylic acids and amides efficiently produces the corresponding silyl ethers and amines, respectively. Reduction of esters gives a mixture of silyl and alkyl ethers, but can be controlled by changing the silanes and solvents.
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stoichiometric and catalytic activation of si h bonds by a triruthenium carbonyl cluster μ3 η2 η3 η 5 Acenaphthylene ru3 co 7 isolation of the oxidative adducts catalytic hydrosilylation of aldehydes ketones and acetals and catalytic polymerization of cyclic ethers
Organometallics, 2000Co-Authors: Hideo Nagashima, Takafumi Iura, Akihiro Suzuki, Kazuhiro Ryu, Kouki MatsubaraAbstract:Treatment of the ruthenium cluster (μ3,η2:η3:η5-Acenaphthylene)Ru3(CO)7 (1) with stoichiometric amounts of trialkylsilanes results in liberation of a CO ligand followed by oxidative addition of a Si−H bond. The trinuclear silyl complexes (μ3,η2:η3:η5-Acenaphthylene)Ru3(H)(SiR3)(CO)6 (2) were isolated in good yield. They were characterized by NMR spectroscopy and X-ray crystallography. Compound 1 catalyzes the hydrosilylation of olefins, acetylenes, ketones, and aldehydes. In particular, the reactions of aldehydes and ketones proceed at room temperature to form the corresponding silyl ethers in good yield; the catalytic activities are superior to those with RhCl(PPh3)3. The RhCl(PPh3)3-catalyzed hydrosilylation of ketones with Me2(H)SiCH2CH2Si(H)Me2 results in selective reaction of only one Si−H terminus, while similar reactions, when catalyzed by 1, allow utilization of both Si−H groups. Significantly different regio- and stereoselectivities, compared with those obtained in reactions catalyzed by RhCl(PPh...
Hideo Nagashima - One of the best experts on this subject based on the ideXlab platform.
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highly efficient catalytic reactions via activation of a si h bond of organohydrosilanes by triruthenium carbonyl clusters bearing bridging an Acenaphthylene or azulene ligand
Journal of Synthetic Organic Chemistry Japan, 2005Co-Authors: Kouki Matsubara, Hideo NagashimaAbstract:Highly efficient catalytic reactions have been achieved via activation of Si-H bonds of organohydrosilanes by triruthenium carbonyl clusters bearing bridging Acenaphthylene or azulene ligands. A ruthenium complex, (μ2, η2:η3:η5-Acenaphthylene) Ru3 (CO)7 (1) catalyzes hydrosilylation of ketones and aldehydes in solution at room temperature to form the corresponding silyl ether in high yields. Prior activation of the catalyst by excess amounts of the hydrosilane results in dramatic increase of the catalytic activity. Application of the hydrosilylation catalyzed by preactivated 1 to the reduction of carboxylic acids and their derivatives has provided efficient preparative methods for silyl and alkyl ethers from esters, silyl ethers from carboxylic acids, and amines from amides, which are hardly achieved with other transition metal catalysts. The cluster 1 also behaves as an active catalyst for ring-opening polymerization of cyclic ethers and cyclic siloxanes and addition polymerization of vinyl ethers, which are induced by hydrosilanes. Spectroscopic analysis of the polymers obtained reveals existence of an organosilyl moiety at the end group, which is useful for further chemical transformation of the formed polymer. Isolation, characterization, and reactions of possible catalytically active species help discussion on the reaction mechanisms, in which a triruthenium hydridosilyl cluster is involved in the catalytic cycle.
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silane induced polymerization of vinyl ethers catalyzed by a triruthenium carbonyl cluster μ3 η2 η3 η5 Acenaphthylene ru3 co 7
Organometallics, 2004Co-Authors: Hideo Nagashima, Chikara Itonaga, Jushiro Yasuhara, Yukihiro Motoyama, Kouki MatsubaraAbstract:The polymerization of vinyl ethers (CH2CHOR, R = nBu, iBu, tBu, iPr) is catalyzed by a ruthenium cluster, (μ3,η2:η3:η5-Acenaphthylene)Ru3(CO)7 (1), using several hydrosilanes as the initiator to gi...
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a triruthenium carbonyl cluster bearing a bridging Acenaphthylene ligand an efficient catalyst for reduction of esters carboxylic acids and amides by trialkylsilanes
ChemInform, 2002Co-Authors: Kouki Matsubara, Takafumi Iura, Tomoyuki Maki, Hideo NagashimaAbstract:An efficient reduction of carboxylic acids, esters, and amides with trialkylsilanes is accomplished using a triruthenium carbonyl cluster bearing a bridging Acenaphthylene ligand, (μ3,η2:η3:η5-Acenaphthylene)Ru3(CO)7, as the catalyst. Preactivation of the catalyst by hydrosilanes accelerates the reactions. Sterically small trialkylsilanes are effective in these reactions. Reduction of carboxylic acids and amides efficiently produces the corresponding silyl ethers and amines, respectively. Reduction of esters gives a mixture of silyl and alkyl ethers, but can be controlled by changing the silanes and solvents.
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stoichiometric and catalytic activation of si h bonds by a triruthenium carbonyl cluster μ3 η2 η3 η 5 Acenaphthylene ru3 co 7 isolation of the oxidative adducts catalytic hydrosilylation of aldehydes ketones and acetals and catalytic polymerization of cyclic ethers
Organometallics, 2000Co-Authors: Hideo Nagashima, Takafumi Iura, Akihiro Suzuki, Kazuhiro Ryu, Kouki MatsubaraAbstract:Treatment of the ruthenium cluster (μ3,η2:η3:η5-Acenaphthylene)Ru3(CO)7 (1) with stoichiometric amounts of trialkylsilanes results in liberation of a CO ligand followed by oxidative addition of a Si−H bond. The trinuclear silyl complexes (μ3,η2:η3:η5-Acenaphthylene)Ru3(H)(SiR3)(CO)6 (2) were isolated in good yield. They were characterized by NMR spectroscopy and X-ray crystallography. Compound 1 catalyzes the hydrosilylation of olefins, acetylenes, ketones, and aldehydes. In particular, the reactions of aldehydes and ketones proceed at room temperature to form the corresponding silyl ethers in good yield; the catalytic activities are superior to those with RhCl(PPh3)3. The RhCl(PPh3)3-catalyzed hydrosilylation of ketones with Me2(H)SiCH2CH2Si(H)Me2 results in selective reaction of only one Si−H terminus, while similar reactions, when catalyzed by 1, allow utilization of both Si−H groups. Significantly different regio- and stereoselectivities, compared with those obtained in reactions catalyzed by RhCl(PPh...
Raju Ranjith Kumar - One of the best experts on this subject based on the ideXlab platform.
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substitution induced switch between pictet spengler and eschweiler clarke reactions selective synthesis of spiro Acenaphthylene pyrrolo 1 2 b isoquinoline pyrrolidine hybrids
Tetrahedron Letters, 2020Co-Authors: Raju Suresh Kumar, Abdulrahman I Almansour, Natarajan Arumugam, Raju Ranjith KumarAbstract:Abstract The 1,3-dipolar cycloaddition of azomethine ylides generated in situ from the decarboxylative condensation of acenaphthenequinone and tyrosine or phenylalanine to β-nitrostyrenes afforded spiro Acenaphthylene-pyrrolidine hybrids. The subsequent reaction of these spiro heterocycles with formaldehyde and trifluoroacetic acid led to the formation of either Pictet-Spengler or Eschweiler-Clarke products depending on the substitution in the benzyl ring. The unsubstituted compounds occurred via Pictet-Spengler route to afford spiro Acenaphthylene pyrrolo[1,2-b]isoquinoline hybrids as expected, whereas the 4-OH substituted compounds proceeded via Eschweiler-Clarke route affording the unexpected N-methylated spiro Acenaphthylene-pyrrolidine hybrids.
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dipolar cycloaddition based multi component reaction synthesis of spiro tethered Acenaphthylene indolizine pyridinone hybrids
Tetrahedron Letters, 2018Co-Authors: Raju Suresh Kumar, Abdulrahman I Almansour, Natarajan Arumugam, Raju Ranjith Kumar, Govindasami Periyasami, S Athimoolam, Mohammad Asad, Abdullah M AsiriAbstract:Abstract The stereoselective syntheses of novel dispiro Acenaphthylene–indolizine–pyridinone hybrid heterocycles have been achieved through one-pot four-component domino 1,3-dipolar cycloaddition–Michael addition–air oxidation sequence of reactions.
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synthesis of novel dispiro 1 4 benzothiazine hybrid heterocycles through 1 3 dipolar cycloaddition
Synthetic Communications, 2015Co-Authors: Karuppiah Malathi, Veerappan Jeyachandran, Karumpan Kalaiselvan, Raju Ranjith KumarAbstract:AbstractThe 1,3-dipolar cycloaddition of azomethine ylides generated in situ from the reaction of Acenaphthylene-1,2-dione or isatins and α-amino acids to (E)-methyl/ethyl 2-(3-oxo-3,4-dihydro-2H-benzo[b][1,4]thiazin-2-ylidene)acetate led to the stereoselective formation of novel dispiro 1,4-benzothiazine hybrid heterocycles in good yields.
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synthesis of novel 16 spiro steroids spiro 7 aryl tetrahydro 1h pyrrolo 1 2 c 1 3 thiazolo trans androsterone hybrid heterocycles
Steroids, 2013Co-Authors: Selvaraj Kanchithalaivan, Raju Ranjith Kumar, Subbu PerumalAbstract:The 1,3-dipolar cycloaddition of azomethine ylide derived in situ from the reaction of Acenaphthylene-1,2-dione and 1,3-thiazolane-4-carboxylic acid to various exocyclic dipolarophiles synthesized from trans-androsterone and trans-dehydroandrosterone afforded a library of novel spiro[5'.2″]Acenaphthylene-1″-one-spiro[16.6']-(7'-aryl)-tetrahydro-1H-pyrrolo [1,2-c][1,3]thiazolo-trans-androsterone/dehydroandrosterone hybrid heterocycles respectively. These reactions proceeded stereo-specifically affording a single isomer of the 16-spiro steroids in excellent yields.
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sequential 1 3 dipolar cycloadditions in the synthesis of novel tri spiro cyclohexanones and piperidin 4 ones
Synthetic Communications, 2009Co-Authors: Raju Ranjith Kumar, Balaganesan Loganayaki, Subbu PerumalAbstract:Abstract The sequential 1,3-dipolar cycloadditions of azomethine ylide and nitrile oxide to a series of 2,6-bis[(E)-arylmethylidene]cyclohexanones and 1-methyl-3,5-bis[(E)-arylmethylidene]tetrahydro-4(1H)-pyridinones afforded novel tri-spiro heterocycles comprising isoxazoline, pyrrolidine and acenaphthylen-1(2H)-one rings in good yields and stereoselectivity.
Kenneth I. Hardcastle - One of the best experts on this subject based on the ideXlab platform.
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Unexpected σ bond rupture during the reaction of N-methyl-1,2,4-triazoline-3,5-dione with Acenaphthylene and indene.
The Journal of organic chemistry, 2014Co-Authors: Gary W. Breton, Joshua S. Hughes, Timothy J. Pitchko, Kenneth L. Martin, Kenneth I. HardcastleAbstract:The reaction of N-methyl-1,2,4-triazoline-3,5-dione (MeTAD) with Acenaphthylene and indene leads not only to the formation of the expected [2 + 2] diazetidine cycloadducts but also to unexpected 2:1 adducts of MeTAD with substrate. The structures of the products derived from Acenaphthylene were confirmed by X-ray crystallography. A similar distribution of products was afforded from indene. The 2:1 adducts appear to derive from a diradical intermediate, the radical centers of which are strongly stabilized by the bridging urazoyl ring and benzylic delocalization. The triplet states of these diradical intermediates may be trapped via exposure to molecular oxygen to afford oxygen-containing adducts. Computational studies at the (U)B3LYP/6-31G* level provide additional support for the conclusions of our experimental work.
Masaji Oda - One of the best experts on this subject based on the ideXlab platform.
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a simple and versatile synthesis of 1 2 diarylAcenaphthylenes via suzuki miyaura coupling and its application in the synthesis of a new Acenaphthylene 1 2 bis p quinone methide derivative
Synlett, 2007Co-Authors: Hiroyuki Kurata, Yuko Takehara, Kouzou Matsumoto, Takeshi Kawase, Sang Kim, Kanae Sakai, Masaji OdaAbstract:1,2-Diaryl-substituted Acenaphthylene derivatives were prepared simply via Suzuki-Miyaura coupling in good or excellent yields. By applying this method, Acenaphthylene-1,2-bis( P-quinone methide) with two 3,5-di- TERT-butyl-4-oxocyclohexadienylidene units, which is a stable deep purple crystalline substance with a very broad absorption in the whole visible region and relatively low -reduction potential, was prepared and characterized.
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synthesis structure and properties of a cyclopent fg Acenaphthylene 1 2 bis p quinone methide s derivative an extended pyracyloquinone
Chemistry Letters, 2005Co-Authors: Hiroyuki Kurata, Yuko Takehara, Kouzou Matsumoto, Takeshi Kawase, Masaji OdaAbstract:The extended-quinone derivative of cyclopent[fg]Acenaphthylene-1,2-dione (pyracyloquinone) is first synthesized and characterized. An X-ray analysis exhibits the non-planar structure involving bent of two 3,5-di-tert-butyl-4-oxo-cyclohexadienylidene units, and bond alternation along the molecular periphery. The facile formation of trianion radical on cyclic voltammetry reflects high-electron affinity enhanced by antiaromatic character of the formed pyracylene moiety on the dianion state.
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synthesis structure and properties of a cyclopent fg Acenaphthylene 1 2 bis p quinone methide s derivative an extended pyracyloquinone
Chemistry Letters, 2005Co-Authors: Hiroyuki Kurata, Yuko Takehara, Kouzou Matsumoto, Takeshi Kawase, Masaji OdaAbstract:The extended-quinone derivative of cyclopent[fg]Acenaphthylene-1,2-dione (pyracyloquinone) is first synthesized and characterized. An X-ray analysis exhibits the non-planar structure involving bent...