研究者詳細 - 西原　康師

論文 - 西原　康師

分割表示 197 件中 181 - 197 件目／全件表示 >>

Novel cage polycarbosilanes. Preparation and characterization of dodecamethyl-2,3,5,6,7,8-hexasilabicyclo[2.2.2]octane and its derivatives

Masaki Shimizu, Naoko Inamasu, Yasushi Nishihara, Tamejiro Hiyama

Chemistry Letters ( 11 ) 1145 - 1146 1998年

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Chemical Society of Japan

2,2,3,3,5,5,6,6,7,7,8,8-Dodecamethyl-2,3,5,6,7,8-hexasilabicyclo[2.2.2] octane (1) was synthesized for the first time via three steps in 56% overall yield through triple silylation with three dichlorodimethyldisilane molecules of two trianionic molecules derived from bis(phenylthio)methane. The molecular structure of 1 was shown to be slightly distorted from an ideal bicyclo-[2.2.2]octane skeleton by X-ray analysis. The derivatization of 1 and UV spectra of those compounds are described.

DOI： 10.1246/cl.1998.1145

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Preparation and reactions of Cp2HfRCl, Cp2HfRR′ and hafnacyclopent-2-enes 査読

Yasushi Nishihara, Toyohisa Ishida, Shouquan Huo, Tamotsu Takahashi

Journal of Organometallic Chemistry 547 ( 2 ) 209 - 216 1997年12月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Elsevier

Reaction of Cp2HfCl2 with R3Al (R = Et, n-Pr, or n-Bu) in hexane selectively produced monoalkylhafnocene complexes, Cp2HfRCl (1), in high yields. Cp2HfMeCl (1a) was prepared by the reaction of oxo-bridged hafnocene complex (Cp2HfCl)2(μ-O) with Me3Al. The treatment of 1 with alkylating reagents such as R′Li or EtMgBr afforded unsymmetrical dialkylhafnocene complexes Cp2HfRR′ (3) in good to excellent yields. The kinetic study of thermolysis of Cp2HfEtR (R = Me, Et, n-Bu, sec-Bu, t-Bu or Ph) suggested that decomposition of Cp2HfEt(sec-Bu) was much faster than the others. Cp2Hf(sec-Bu)2 (2e) can be used as a good precursor of Cp2Hf(II) species. Hafnacyclopent-2-enes (4) were prepared in good yields by the reaction of Cp2HfEt2 (2b) with alkynes. © 1997 Elsevier Science S.A.

DOI： 10.1016/S0022-328X(97)00375-6

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Highly regio- and diastereo-selective carbon-carbon bond formation reaction of unsymmetrical zirconacyclopentanes using copper salt 査読

T Takahashi, Y Nishihara, R Hara, SQ Huo, M Kotora

CHEMICAL COMMUNICATIONS ( 17 ) 1599 - 1600 1997年9月

Convenient preparative method of alpha,beta-disubstituted cyclopentenone by zirconium promoted intermolecular coupling of an alkyne, EtMgBr (or ethylene) and CO 査読

T Takahashi, ZF Xi, Y Nishihara, SQ Huo, K Kasai, K Aoyagi, Denisov, V, E Negishi

TETRAHEDRON 53 ( 27 ) 9123 - 9134 1997年7月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：PERGAMON-ELSEVIER SCIENCE LTD

Treatment of Cp2ZrCl2 with 2 equiv of EtMgBr in THF, followed by addition of an internal alkyne and subsequent treatment with CO/I-2 gave alpha,beta-disubstituted cyclopentenone in good to high yields. When a conjugated enyne was used as an alkyne component, alpha-alkenyl cyclopentenone was selectively formed in 80-89% yields. In the case of 4,6-decadiyne, alpha-alkynylcyclopentenone was formed in 88% yield. Bridged alkynes such as 1,4-dihexynytbenzene afforded alpha alpha'-bridged cyclopentenone compounds in good yields. (C) 1997 Elsevier Science Ltd.

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Coupling reaction of alkenylzirconocenes with aryl or alkenyl iodides in the presence of CuCl/Pd(PPh(3))(4) 査読

R Hara, Y Nishihara, PD Landre, T Takahashi

TETRAHEDRON LETTERS 38 ( 3 ) 447 - 450 1997年1月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：PERGAMON-ELSEVIER SCIENCE LTD

Trisubstituted alkenylalkoxyzirconocenes which have been prepared from carbozirconation reactions of internal alkynes via zirconacyclopentenes reacted with aryl or alkenyl iodides in the presence of CuCl and a catalytic amount of Pd(PPh(3))(4) to give coupling products. Copyright (C) 1996 Elsevier Science Ltd

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Zirconocene catalyzed dehalogenation of aromatic halides by alkylmagnesium reagents 査読

R Hara, WH Sun, Y Nishihara, T Takahashi

CHEMISTRY LETTERS ( 12 ) 1251 - 1252 1997年

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：CHEMICAL SOC JAPAN

When aromatic halides were treated with alkylmagnesium reagents (which have beta-hydrogens) and a catalytic amount of zirconocene dichloride, dehalogenation proceeded smoothly in high yields. The stoichiometric dehalogenation using dialkylzirconocenes also proceeded with high selectivities.

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Cu(I)/Pd(0)-catalyzed cross-coupling reaction of alkynylsilanes with aryl or alkenyl triflates: "Sila"-Sonogashira-Hagihara coupling 査読

Nishihara Y, Ikegashira K, Mori A, Hiyama T

Chemistry Letters 1997 ( 12 ) 1233 - 1234 1997年

記述言語：英語出版者・発行元：The Chemical Society of Japan

Alkynylsilanes reacted with aryl or alkenyl triflates in the presence of 5 mol% of Pd(PPh₃)₄ and 10 mol% of CuCl in DMF to give the corresponding cross-coupling, namely "sila"-Sonogashira-Hagihara coupling, products in good to excellent yields. The present reaction is highly effective for one-pot synthesis of unsymmetrical diarylacetylenes.

DOI： 10.1246/cl.1997.1233

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その他リンク： http://orcid.org/0000-0002-1163-264X

Copper(I) salt promoted homo-coupling reaction of organosilanes 査読

Ikegashira K, Nishihara Y, Hirabayashi K, Mori A, Hiyama T

Chemical Communications ( 11 ) 1039 - 1040 1997年

TBAHF(2) and TBAH(2)F(3) as activating agents of organosilanes 査読

Mori A, Fujita A, Ikegashira K, Nishihara Y, Hiyama T

Synlett ( 6 ) 693 - 694 1997年

Copper(I) salt mediated 1,4-reduction of alpha,beta-unsaturated ketones using hydrosilanes 査読

Mori A, Fujita A, Nishihara Y, Hiyama T

Chemical Communications 1997 ( 22 ) 2159 - 2160 1997年

Highly selective monofunctionalization of zirconacyclopentanes and dialkylzirconocene complexes 査読

Y Nishihara, K Aoyagi, R Hara, N Suzuki, T Takahashi

INORGANICA CHIMICA ACTA 252 ( 1-2 ) 91 - 99 1996年11月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：ELSEVIER SCIENCE SA LAUSANNE

Selective monofunctionalization was investigated for symmetrical zirconacyclopentanes or symmetrical dialkylzirconocenes. Reaction of zirconacyclopentanes, which were prepared by intermolecular coupling of two alkenes, or intramolecular cyclization of dienes, trienes or tetraenes on zirconium, with PPh(2)Cl or SnR(3)Cl (R = Me, Ph) gave monofunctionalized products in good to high yields with high selectivities. Even in the presence of 2 equiv, of PPh(2)Cl or SnR(3)Cl, only one Zr-carbon bond reacted. Treatment of zirconacycropentanes with methanol yielded monoprotonated complexes. Subsequent addition of halogen such as Br-2 and I-2 to these monoprotonated complexes gave highly selective monohalogenated products. Similar monoprotonation reactions proceeded for dialkylzirconocene or -hafnocene complexes. Reaction of Cp(2)MR(2) (M = Zr or Hf, R = alkyl or aryl) with alcohols afforded alkylalkoxyzirconocene or -hafnocene complexes, Cp(2)MR(OR') (M = Zr or Hf, R' = alkyl or aryl) in high yields with high selectivities. High selectivity of monofunctionalization using PPh(2)Cl, SnR(3)Cl or alcohols can be attributed to the different reactivities between monoalkylzirconocenes which are monofunctionalized products and zirconacyclopentanes or dialkylzirconocenes.

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Copper-mediated coupling of zirconacyclopentadienes with dihalo aromatic compounds. Formation of fused aromatic rings 査読

T Takahashi, R Hara, Y Nishihara, M Kotora

JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 118 ( 21 ) 5154 - 5155 1996年5月

High Yield Synthesis and Characterization of Chromaboranes. Comparison of the Geometric, Electronic, and Chemical Properties of an Electronically Unsaturated (.eta.5-C5Me5)2Cr2B4H8 Cluster with Its Saturated Derivative (.eta.5-C5Me5)2Cr2(CO)2B4H6 査読

Jianwei Ho, Kathryn J. Deck, Yasushi Nishihara, Maoyu Shang, Thomas P. Fehlner

Journal of the American Chemical Society 117 ( 41 ) 10292 - 10299 1995年10月

PRACTICAL AND SELECTIVE METHOD FOR PREPARATION OF CP(2)HFRCL AND CP(2)HFRR' 査読

T TAKAHASHI, Y NISHIHARA, T ISHIDA

CHEMISTRY LETTERS ( 2 ) 159 - 160 1995年2月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：CHEMICAL SOC JAPAN

Practical method for preparation of Cp(2)HfRCl and Cp(2)HfRR' has been investigated. Mono(alkyl)hafnocene chloride complexes were selectively prepared by the following methods; (i) a reaction of Cp(2)HfR(OMe) with MeCOCl and (ii) a reaction of Cp(2)HfCl(2) with an excess of R(3)Al. Treatment of Cp(2)HfRCl with R'Al-3 led to an alkyl exchange reaction to form Cp(2)HfR'Cl. Mono(alkyl)hafnocene complexes prepared by (ii) reacted with one equiv of R'Li to give Cp(2)HfRR' (R not equal R') with a high selectivity.

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Oxidative Addition of 2-Haloalkene to Zirconocene 査読

Tamotsu Takahashi, Martin Kotora, Reinald Fischer, Yasushi Nishihara, Kiyohiko Nakajima, Tamotsu Takahashi

Journal of the American Chemical Society 117 ( 44 ) 11039 - 11040 1995年

Preparation and Structure of (Cp*Cr)2B4H8. An Unsaturated Metallaborane Cluster with an Unexpected Structure 査読

Kathryn J. Deck, Yasushi Nishihara, Maoyu Shang, Thomas P. Fehlner

Journal of the American Chemical Society 116 ( 18 ) 8408 - 8409 1994年9月

Cluster chemistry driven by ligand bulk. Significance of the synthesis of nido-1-(.eta.5-C5Me5)Co-2-(.eta.4-C5Me5H)CoB3H8 and its dehydrogenation to nido-2,4-{(.eta.5-C5Me5)Co}2B3H7 査読

Yasushi Nishihara, Kathryn J. Deck, Maoyu Shang, Thomas P. Fehlner

Journal of the American Chemical Society 115 ( 25 ) 12224 - 12225 1993年12月

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