有機合成化学協会誌
Online ISSN : 1883-6526
Print ISSN : 0037-9980
ISSN-L : 0037-9980
73 巻 , 8 号
選択された号の論文の10件中1~10を表示しています
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総説および総合論文
  • 重久 浩樹, 廣谷 功
    2015 年 73 巻 8 号 p. 788-797
    発行日: 2015/08/01
    公開日: 2015/09/25
    ジャーナル 認証あり
    Recent developments of Markovnikov selective hydrofunctionalization of olefins are discussed. It is note that we realized hydrofunctionalization such as an intermolecular hydroalkoxylation, a hydrofluorination, and an intramolecular hydroamination with excellent functional group tolerance using cobalt complex, N-fluoropyridinium salt, and disiloxane. Mechanistically, this catalysis involves both carbon radical and carbocation intermediate.
  • 五月女 宜裕
    2015 年 73 巻 8 号 p. 798-809
    発行日: 2015/08/01
    公開日: 2015/09/25
    ジャーナル 認証あり
    In nature, enzymes can display diverse catalytic functions by exploiting structural changes in response to various external stimuli. Inspired by these flexible but well-controlled functions of enzymes, we have explored the conformationally flexible organocatalysts, which enable to construct enantiomerically distinct chiral environments with a single chiral source. Here we describe recent advances in the development of dynamic asymmetric organocatalysis, including retro-free, enantiodivergent, entropy-controlled organocatalysis, and programmed-organocascade, in which a single asymmetric organocatalyst can afford different functional outcomes by timely tuning the reaction conditions. Special emphasis is placed on key requirements to attain high selectivity and on functional switching by exploiting the structural flexibility of our organocatalysts.
  • 美多 剛
    2015 年 73 巻 8 号 p. 810-820
    発行日: 2015/08/01
    公開日: 2015/09/25
    ジャーナル 認証あり
    I herein describe iridium- and rhodium-catalyzed C(sp3)-H silylation at the benzylic position and the position adjacent to a nitrogen atom by the aid of a nitrogen directing group. The silylated products could be further carboxylated with carbon dioxide (1 atm of CO2) under fluoride-mediated conditions, giving carboxylic acid derivatives in high yields. It should be a formal carboxylation of C(sp3)-H bonds triggered by metal-catalyzed C-H silylation. We also developed a novel triborylation reaction of terminal C(sp3)-H bonds (2-ethylpyridine derivatives). The obtained triborylated compounds were successfully converted into carboxylic acids by using either CsF under a CO2 atmosphere or H2O2 in the presence of TsOH·H2O.
  • 樋口 和宏, 杉山 重夫, 川﨑 知己
    2015 年 73 巻 8 号 p. 821-832
    発行日: 2015/08/01
    公開日: 2015/09/25
    ジャーナル 認証あり
    2,2-Disubstituted 1,2-dihydro-3H-indol-3-ones are useful synthetic intermediates for natural products. Therefore, its preparation in a concise manner is highly desirable. Recently, we reported a methodology for the preparation of 2,2-disubstituted 1,2-dihydro-3H-indol-3-ones through the successive oxidation of indoles and Mannich-type reaction of 2-hydroxy-1,2-dihydro-3H-indol-3-ones with various carbon nucleophiles. Using this method, we accomplished the total synthesis of (±)-hinckdentine A. The synthesis featured seven-membered lactam formation by Murahashi’s Ru catalyst and the selective tri-bromination of aromatic ring. Also, we performed the synthesis of isatisine A framework. In this research, we found an intriguing reaction in which nucleophiles are introduced at the C-2 position of 3H-indol-3-one via activation with TFAA. Towards the total synthesis of leuconoxine, ring construction steps featuring the N-acyliminium mediated intramolecular piperidine cyclization and the one-step pyrrolidone formation using Bestmann’s ylide are achieved successfully. Utilization of a chiral phosphoric acid catalyst (VAPOL PA), the asymmetric desymmetrization of prochiral diester produced highly-enantioenriched lactam in excellent yield. Using this strategy, we accomplished the asymmetric total synthesis of (−)-leuconoxine.
  • 古山 渓行, 小林 長夫
    2015 年 73 巻 8 号 p. 833-843
    発行日: 2015/08/01
    公開日: 2015/09/25
    ジャーナル 認証あり
    Azaporphyrinoids, such as phthalocyanines (Pcs), tetraazaporphyrins (TAPs), and tetrabenzotriazacorroles (TBCs) are some of the most well-known and successful artificial dyes and pigments in modern material chemistry. In this article, on modifying optical properties of azaporphyrins, we have proposed a novel “π electron-unmodified” approach by utilizing the unique properties of the phosphorus(V) ion with simple macrocyclic ligands. Although the azaporphyrin phosphorus(V) complexes could be synthesized via simple synthetic procedures, they revealed unique optical properties not seen in other metalloazaporphyrinoids reported to date, such as intense absorption and fluorescence bands beyond 1,000 nm, broad absorption bands across the entire UV-vis region, and high singlet oxygen quantum yields. The combination of peripheral substituents and theoretical calculations was effective for the rational design of optical properties in the UV-vis-near-IR region, which is also demonstrated. The practical synthesis, purification, and characterization of azaporphyrins have also been described for general organic synthetic chemists.
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