巻号一覧
48 巻, 5 号
選択された号の論文の7件中1～7を表示しています
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津田 鉄雄, 清位 孝夫, 長谷川 直樹, 三枝 武夫1990 年 48 巻 5 号 p. 362-369
発行日: 1990/05/01
公開日: 2009/11/13
ジャーナル フリーTransition metal-catalyzed carbon dioxide fixation into unsaturated hydrocarbons is an important problem. On the basis of two new approaches, i.e., use of reactive substrates of diynes and alkoxyacetylenes and synthesis of a trialkylphosphine ligand containing a pyridyl functional group, we have developed an efficient and selective nickel (0) -catalyzed cycloaddition reaction of acetylenes with carbon dioxide to various 2-pyrones. By the use of aldehydes instead of carbon dioxide, we have also developed a nickel (0) tertiary phosphine complex-catalyzed reaction of diynes and monoynes with aldehydes, which provides synthetic methods of bicyclic 2H-pyrans, functionalized carbo and heterocycles and α, β-enones.抄録全体を表示PDF形式でダウンロード (971K) -
伊与田 正彦1990 年 48 巻 5 号 p. 370-380
発行日: 1990/05/01
公開日: 2009/11/13
ジャーナル フリーNew Synthetic methods for preparing highly unsaturated compounds are developed by using the nickel-catalyzed cyclooligomerization of cumulenes, carbenoids, and benzocyclobutadiene, and the nickel-catalyzed Ullmann coupling of organic halides. [3] Cumulenes (butatrienes), which are generated in situ from various precursors, react with nickel (0) complexes to produce [4] radialenes in benzene and THF or [6] radialenes in DMF. The formation of dimers and trimers depends on the solvent used. Reaction of [5] cumulenes (hexapentaenes) with Ni (CO)2 (PPh3)2 yields very unique compounds containing radialene frameworks. Furthermore, reaction of nickel carbenoids proceeds formally as a cyclooligomerization of the carbene center to give [3] -, [4] -, and [5] radialenes. This one-step method has been applied to the synthesis of radialenes containing functional groups. The nickel-catalyzed Ullmann coupling of vinyl halides can be also achieved to give novel π-electron systems. Nickel-mediated synthesis of trimers of benzocyclobutadiene is demonstrated with mechanistic explanation.抄録全体を表示PDF形式でダウンロード (1236K) -
玉尾 皓平, 小林 健二, 伊藤 嘉彦1990 年 48 巻 5 号 p. 381-388
発行日: 1990/05/01
公開日: 2009/11/13
ジャーナル フリーNickel (0) -mediated intramolecular cyclizations of enynes and diynes have mainly been described. The article includes the following topics. (1) Cyclization of 1, n-enynes and dienynes with isocyanides to produce polycyclic iminocyclopentenes. (2) Cyclization of 1, n-diynes with isocyanides to form polycyclic iminocyclopentadienes. (3) Cyclization of 1, 6-diynes with “silylenes” to produce bicyclic silacyclopentadienes. (4) Cyclization of 1, 7-diynes with hydrosilanes to form 1, 2-dialkylidenecyclohexanes bearing a (Z) -vinylsilane moiety. (5) Cyclization of bis-dienes with hydrosilanes to give 1, 2-divinylcyclopentanes having an allylsilane moiety. Properties, reactivities and synthetic utilities of new ring systems thus obtained are also described.抄録全体を表示PDF形式でダウンロード (878K) -
野出 学, 冨士 薫1990 年 48 巻 5 号 p. 389-402
発行日: 1990/05/01
公開日: 2009/11/13
ジャーナル フリーNitroolefins are versatile synthetic intermediates in organic synthesis because of excellent ability for carbon-carbon bond formation and easy transformation to a variety of functional groups. In the reaction of enolates with chiral nitroolefins, a chiral hetero substituent is replaced by the carbon substituents via addition-elimination process. The scope, limitations, and the mechanism for this type of asymmetric induction will be discussed. The resulting chiral nitroolefins have a wide utility as chiral building blocks for the chiral syntheses of the natural products, such as Aspidosperma, Hunteria, and Physostigma alkaloids, tricyclic diterpenoids and sesquiterpenoids.抄録全体を表示PDF形式でダウンロード (1520K) -
岩月 章治1990 年 48 巻 5 号 p. 403-415
発行日: 1990/05/01
公開日: 2009/11/13
ジャーナル フリーPolymerizations of unsubstituted quinodimethane which is too reactive to be obtainable as condense state, were described in the flash pyrolysis and vapor-coating methods. Chlorine-substituted quinodimethanes were compared with the number of chlorine-substituents. Electron-accepting, substituted quinodimethanes like TCNQ, obtainable as stable crystalline compounds, are not homopolymerizable but copolymerizable with donor monomers like styrene in an alternating fashion. Tetrakis (methoxycabonyl) - and tetrakis (ethoxycarbonyl) -quinodimethane exhibit amphoteric behavior in their alternating copolymerizations. Some quinodimethanes with different two substituents at 7 and 8 positions are homopolymerizable, for instance, anionic polymerization of BCQ occured in living type and gave the polymer with molecular weight above million. Their homopolymerizations also showed an equilibrium behavior which allowed us to determine thermodynamic data for polymerization of those monomers. Their copolymerizations with styrene occurs in random fashion The cross propagation step was studied in detail by means of linear free energy relationship.抄録全体を表示PDF形式でダウンロード (1542K) -
森田 泰彦1990 年 48 巻 5 号 p. 416-417
発行日: 1990/05/01
公開日: 2009/11/13
ジャーナル フリーL-アスコルビン酸 (以下L-AsAと略す) は抗壊血病活性をもつ水溶性ビタミンで一般にはビタミンCとして知られている。AsAにはL-体とD-体とが存在するが, 抗壊血病作用をもつのはL-体でD-体はほとんど作用がない。1920年に抗壊血病作用を示す成分がビタミンCと
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命名された (Drummondにより) が, その後Szent-Gyorgyiらがウシの副じん (腎), オレンジ, キャベッ等から結晶として単離してヘキスロン酸と命名した物質がビタミンCと同一物質であることが確認され, 抗壊血病の意味からアスコルビン酸と命名された。天然にはかんきつ (柑橘) 類, そ (蔬) 菜類, 緑茶等に多く含まれているが, 純度の高い結晶が容易に大量生産されるので天然物から抽出, 単離することは行われていない。抄録全体を表示PDF形式でダウンロード (235K) -
津田 鉄雄, 伊与田 正彦, 玉尾 皓平, 野出 学1990 年 48 巻 5 号 p. 418
発行日: 1990/05/01
公開日: 2009/11/13
ジャーナル フリーPDF形式でダウンロード (139K)
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