Take-aki Mitsudo
Kyoto University
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Featured researches published by Take-aki Mitsudo.
Tetrahedron Letters | 1987
Take-aki Mitsudo; Yoji Hori; Yasushi Yamakawa; Yoshihisa Watanabe
Abstract Secondary amines react with carbon dioxide and terminal alkynes in the presence of a catalytic amount of 4-1,5-cyclooctadiene) (6-1,3,5-cyclooctatriene)ruthenium [Ru(COD)(COT)] and tertiary phosphine in toluene to give enol carbamates in good yields with high regio- and stereoselectivity. Cyclic enol carbamates, 5-methylene-2-oxazolidinones are obtained from N-substituted propargylamines and carbon dioxide in high yields.
Journal of Organometallic Chemistry | 1993
Shi-Wei Zhang; Take-aki Mitsudo; Teruyuki Kondo; Yoshihisa Watanabe
Abstract Allylic carbonates except for allyl methyl carbonate reacted with carbonucleophiles such as ethyl acetoacetate in the presence of a catalytic amount of Ru(cod)(cot) [cod = cycloocta-1,5-diene, cot = cycloocta-1,3,5-triene] in N -methylpiperidine at 80°C to give the corresponding monoallylated carbonucleophiles in high yields with high regioselectivity. The regioselectivity was quite different from that in the palladium-catalyzed reactions. The allylation of carbonucleophiles using allyl methyl carbonate selectively gave the diallylated carbonucleophiles in high yields.
Journal of Organometallic Chemistry | 2001
Teruyuki Kondo; Takumi Okada; Toshiaki Suzuki; Take-aki Mitsudo
Low-valent ruthenium complexes with a p-acidic ligand, such as Ru(h 6 -cot)(dmfm)2 [cot 1,3,5-cyclooctatriene, dmfm dimethyl fumarate] and Ru3(CO)12, showed high catalytic activity for the intramolecular hydroamination of aminoalkynes. The reaction is highly regioselective, in which a nitrogen atom is selectively attached to an internal carbon of alkynes to give five-, six-, and seven-membered nitrogen heterocycles as well as indoles in good to high yields.
Fuel | 1980
Yoshinobu Takegami; Yoshihisa Watanabe; Toshimitsu Suzuki; Take-aki Mitsudo; Maki Itoh
Proton and carbon-13 nuclear magnetic resonance spectroscopy of various vacuum residues and their fractionated samples were carried out to investigate average molecular structures. The structural parameters derived from carbon distribution agreed with those derived from p.m.r. within experimental error. In the aliphatic region of the c.m.r. spectra, characteristic peaks assignable to (CH2)n − n ≧ 6 (29.7 ppm) and CH3CH2CH2CH2 (14.1 ppm) etc. can be observed. The relative intensities of these peaks suggest that the methylene chain contained in vacuum residues is much longer ((CH2)n − n ≧ 12) than has been considered previously. Using the information about the aliphatic region of the c.m.r. spectrum and the structural parameters, an average structural model was deduced.
Journal of Organometallic Chemistry | 1987
Take-aki Mitsudo; Yoji Hori; Yoshihisa Watanabe
Abstract The characteristic catalytic activities of low valence ruthenium complexes, (cyclooctadiene)(cyclooctatriene)ruthenium and its derivatives, in organic syntheses have been exhibited by reviewing the recently developed novel reactions; (1) the first linear co-dimerization of acetylenes with 1,3-dienes (2) the [2 + 2] cross cycloaddition of norbornenes with dimethyl acetylenedicarboxylate (3) the addition of carboxylic acid to acetylenes giving enol esters.
Tetrahedron Letters | 1986
Take-aki Mitsudo; Yoji Hori; Yasushi Yamakawa; Yoshihisa Watanabe
Carboxylic acids react with acetylenes in the presence of a catalytic amount of bis(η5-cyclooctadienyl)ruthenium-PR3-maleic anhydride in toluene to give enol esters in good to excellent yields with high regioselectivity.
Journal of the Chemical Society, Faraday Transactions | 1998
Kenji Wada; Hiroshi Yamada; Yoshihisa Watanabe; Take-aki Mitsudo
Selective photooxidation of light alkanes, mainly methane and ethane, into the corresponding aldehydes was achieved using silica-supported vanadium oxide catalysts under UV irradiation at elevated temperature. Photooxidation of methane using the V2O5/SiO2-IW (incipient wetness) (0.6 mol% V) catalyst at 493 K for 2 h gave 68 µmol of methanal, which corresponds to 76 mol% selectivity and 0.48 mol% one-pass yield. Photooxidation of ethane using V2O5/SiO2 (calcined at 1023 K) -IW (0.6 mol% V) catalyst for 1 h gave 85 µmol of ethanal, which corresponds to 90% selectivity and 1.1% one-pass yield. The catalysts prepared by the sol–gel method also showed activity, especially for the reaction of ethane. Both UV irradiation and a reaction temperature as high as 500 K were essential. The photo-assisted catalytic reactions were very sensitive to the reaction temperature, method of preparation of the catalyst, and addition of water vapour. While the reaction of methane was inhibited by the addition of water vapour, the photooxidation of ethane and propane was promoted in the presence of a controlled amount of water vapour. In addition, the reaction with methane required UV irradiation at a wavelength <310 nm, whereas the reaction with ethane or propane proceeded by irradiation at longer wavelength. According to Raman and UV diffuse reflectance spectroscopic studies and XRD studies, only isolated four-coordinated vanadium oxide surface species were considered to show catalytic activity toward the photooxidation of methane, while accumulated vanadium surface species, not crystalline V2O5, were shown to be active for the photooxidation of ethane and propane.
Tetrahedron Letters | 1992
Take-aki Mitsudo; Shi-Wei Zhang; Teruyuki Kondo; Yoshihisa Watanabe
Abstract Ru(cod)(cot) catalyzes highly selective codimerization of 1,3-dienes with acrylic compounds and first linear coupling reaction of allylic carbonates with the acrylic amide to give 3,5-dienoic acid derivatives; cod = cycloocta-1,5-diene, cot = cycloocta-1,3,5-triene.
Journal of Molecular Catalysis A-chemical | 1999
Take-aki Mitsudo; Nobuyoshi Suzuki; Taka-aki Kobayashi; Teruyuki Kondo
Abstract The Ru 3 (CO) 12 /1,10-phenanthroline-catalyzed hydroformylation of styrene under 100 atm of syngas (CO:H 2 =1:1) at 120°C in DMF gives the corresponding branched and linear aldehydes in 58 and 22% yields, respectively. With the use of quinuclidine as a ligand in place of 1,10-phenanthroline in N , N -dimethylacetamide, the corresponding branched and linear oxo-alcohols were obtained in 53 and 28% yields, respectively. Hydroformylation of methyl acrylate by a catalyst system of Ru 3 (CO) 12 /1,10-phenanthroline to afford 4-methoxy-4-methyl- δ -valerolactone 1 in 31% yield, while the catalyst system of Ru 3 (CO) 12 /PPh 3 yields the open-chain aldehyde, dimethyl 2-formyl-2-methylglutarate ( 3 ), which is the precursor of lactone 1 in 18% yield.
Journal of Organometallic Chemistry | 1995
Shi-Wei Zhang; Take-aki Mitsudo; Teruyuki Kondo; Yoshihisa Watanabe
Abstract Allylic compounds such as allyl alcohols and allylamines react with two equivalent moles of acetoacetates in the presence of a catalytic amount of Ru(cod)(cot) (cod = cycloocta-1,5-diene; cot = cycloocta-1,3,5-triene) at 100°C for 5 h to give cyclohexenone derivatives in high yields.