Tsuneo HAGIWARA | Yokohama National University (original) (raw)
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Papers by Tsuneo HAGIWARA
Chemischer Informationsdienst, Sep 2, 1975
Journal of Organic Chemistry, 2000
Reactions of R-sulfinyl carbanions, derived from p-tolyl sulfoxides bearing various alkyl groups,... more Reactions of R-sulfinyl carbanions, derived from p-tolyl sulfoxides bearing various alkyl groups, with various electrophiles were examined. The reaction of R-sulfinyl carbanions, derived from the-silylethyl sulfoxides, with ketones or trimethyl phosphate, gave the syn products with high stereoselectivity. Interaction between the silicon in the trialkylsilyl group and the carbonyl oxygen in nucleophiles was postulated to stabilize the transition state, leading preferably to the syn diastereisomers. This novel silicon-oxygen interaction was supported by an MO calculation study using the MOPAC 93/PM3 and the Gaussian 94 Beche3LYP/3-21+G* methods.
Chemischer Informationsdienst, Jul 23, 1974
Tetrahedron, 1992
Abstract The dilithiated compound 3 reacted with 1,3-dichlorotrisilane to give [3.1.1]trisilaprop... more Abstract The dilithiated compound 3 reacted with 1,3-dichlorotrisilane to give [3.1.1]trisilapropellane 1 as a stable form. The reaction of 3 with 1,2-dichlorodisilane gave the ether-incorporated product 9 through [2.1.1]dislapropellane 13. Reductive coupling of the bissilylated tricyclo[4.1.0.02,7]heptane 23a also provided [3.1.1]disiloxapropellane 25 via the intermediate of [2.1.1]disilapropellane 24a. The compounds 1 and 25 show an unique reactivity in the presence of acid to give 7 and 27. The structures of 7 and 27 sharing common ring system have been determined by 2D-NMR and X-ray crystal analysis, respectively. Theoretical studies are also carried out by MNDO method.
ChemInform, Jun 8, 2010
2001 diastereoselective syntheses, enantioselective syntheses diastereoselective syntheses, enant... more 2001 diastereoselective syntheses, enantioselective syntheses diastereoselective syntheses, enantioselective syntheses (incl. cis/trans-isomerism) O 0031 48-041 Stereoselective Reactions of Acylic Allylic Phosphates with Organocopper Reagents.-Optically active phosphates (III) derived from acyclic allylic alcohols give with organocopper compounds (IV), (VI), and (VII) S N 2' reaction products in general with high regio-and stereoselectivities. The dependence of the regio-and stereoselectivities on the size of the substituents R 2 and at the copper compounds is discussed.-(BELELIE,
NIHON GAZO GAKKAISHI (Journal of the Imaging Society of Japan), 2015
Synthetic Metals, 1989
Poly(3,4-dimethoxythiophene) was newly synthesized, and its structure and properties were investi... more Poly(3,4-dimethoxythiophene) was newly synthesized, and its structure and properties were investigated. The polymerization was carried out by anodic oxidation of 3,4-dimethoxythiophene. Typically, the polymer with perchlorate as a counter ion was obtained as a dark-brown amorphous film and gave a conductivity of 64 S/cm. This film was able to be stretched up to 1.2 times its original length, giving a conductivity of 120 S/cm in the stretched direction. Elemental analysis gave a composition of C6.00H6.40S1.00(C104}0.31. The as-grown film showed an absorption spectrum with a broad band around 1700 nm, while the undoped film showed a spectrum with peaks at 510(sh), 551 and 598 nm. The DSC curve showed an exothermic peak at 175 °C, probably due to the dissociation of the counter ion.
DENSHI SHASHIN GAKKAISHI, 2015
Bulletin of the Chemical Society of Japan, 1975
Journal of the Japan Society for Precision Engineering, 2004
Journal of the American Chemical Society, 1972
The photodecarbonylations,2 as well as the thermally induced decarbonylations, 3 of cyclic unsatu... more The photodecarbonylations,2 as well as the thermally induced decarbonylations, 3 of cyclic unsaturated ketones are intriguing problems from experimental and theoretical points of view.4 For instance, cyclohepta-3,5-dienone, upon irradiation, gives rise to a cheletropic
Journal of Polymer Science: Polymer Chemistry Edition, 1985
ABSTRACT
Chemischer Informationsdienst, Sep 2, 1975
Journal of Organic Chemistry, 2000
Reactions of R-sulfinyl carbanions, derived from p-tolyl sulfoxides bearing various alkyl groups,... more Reactions of R-sulfinyl carbanions, derived from p-tolyl sulfoxides bearing various alkyl groups, with various electrophiles were examined. The reaction of R-sulfinyl carbanions, derived from the-silylethyl sulfoxides, with ketones or trimethyl phosphate, gave the syn products with high stereoselectivity. Interaction between the silicon in the trialkylsilyl group and the carbonyl oxygen in nucleophiles was postulated to stabilize the transition state, leading preferably to the syn diastereisomers. This novel silicon-oxygen interaction was supported by an MO calculation study using the MOPAC 93/PM3 and the Gaussian 94 Beche3LYP/3-21+G* methods.
Chemischer Informationsdienst, Jul 23, 1974
Tetrahedron, 1992
Abstract The dilithiated compound 3 reacted with 1,3-dichlorotrisilane to give [3.1.1]trisilaprop... more Abstract The dilithiated compound 3 reacted with 1,3-dichlorotrisilane to give [3.1.1]trisilapropellane 1 as a stable form. The reaction of 3 with 1,2-dichlorodisilane gave the ether-incorporated product 9 through [2.1.1]dislapropellane 13. Reductive coupling of the bissilylated tricyclo[4.1.0.02,7]heptane 23a also provided [3.1.1]disiloxapropellane 25 via the intermediate of [2.1.1]disilapropellane 24a. The compounds 1 and 25 show an unique reactivity in the presence of acid to give 7 and 27. The structures of 7 and 27 sharing common ring system have been determined by 2D-NMR and X-ray crystal analysis, respectively. Theoretical studies are also carried out by MNDO method.
ChemInform, Jun 8, 2010
2001 diastereoselective syntheses, enantioselective syntheses diastereoselective syntheses, enant... more 2001 diastereoselective syntheses, enantioselective syntheses diastereoselective syntheses, enantioselective syntheses (incl. cis/trans-isomerism) O 0031 48-041 Stereoselective Reactions of Acylic Allylic Phosphates with Organocopper Reagents.-Optically active phosphates (III) derived from acyclic allylic alcohols give with organocopper compounds (IV), (VI), and (VII) S N 2' reaction products in general with high regio-and stereoselectivities. The dependence of the regio-and stereoselectivities on the size of the substituents R 2 and at the copper compounds is discussed.-(BELELIE,
NIHON GAZO GAKKAISHI (Journal of the Imaging Society of Japan), 2015
Synthetic Metals, 1989
Poly(3,4-dimethoxythiophene) was newly synthesized, and its structure and properties were investi... more Poly(3,4-dimethoxythiophene) was newly synthesized, and its structure and properties were investigated. The polymerization was carried out by anodic oxidation of 3,4-dimethoxythiophene. Typically, the polymer with perchlorate as a counter ion was obtained as a dark-brown amorphous film and gave a conductivity of 64 S/cm. This film was able to be stretched up to 1.2 times its original length, giving a conductivity of 120 S/cm in the stretched direction. Elemental analysis gave a composition of C6.00H6.40S1.00(C104}0.31. The as-grown film showed an absorption spectrum with a broad band around 1700 nm, while the undoped film showed a spectrum with peaks at 510(sh), 551 and 598 nm. The DSC curve showed an exothermic peak at 175 °C, probably due to the dissociation of the counter ion.
DENSHI SHASHIN GAKKAISHI, 2015
Bulletin of the Chemical Society of Japan, 1975
Journal of the Japan Society for Precision Engineering, 2004
Journal of the American Chemical Society, 1972
The photodecarbonylations,2 as well as the thermally induced decarbonylations, 3 of cyclic unsatu... more The photodecarbonylations,2 as well as the thermally induced decarbonylations, 3 of cyclic unsaturated ketones are intriguing problems from experimental and theoretical points of view.4 For instance, cyclohepta-3,5-dienone, upon irradiation, gives rise to a cheletropic
Journal of Polymer Science: Polymer Chemistry Edition, 1985
ABSTRACT