有機合成化学協会誌
Online ISSN : 1883-6526
Print ISSN : 0037-9980
ISSN-L : 0037-9980
最新号
選択された号の論文の10件中1~10を表示しています
巻頭言
総説および総合論文
  • 猪熊 翼, 山田 健一
    2024 年 82 巻 3 号 p. 222-233
    発行日: 2024/03/01
    公開日: 2024/03/06
    ジャーナル 認証あり

    One of the privileged motifs of chiral N-heterocyclic carbene (NHC) catalyst is an aminoindanol-derived structure, and many researchers achieved an improvement of this type of catalyst by introducing various substitutions at the triazolium nitrogen, which is located at the proximal site of the reactive carbene. Recently, we found that the introduction of substituents at the benzene ring of the indane moiety, which is far from the carbene carbon, could efficiently tune the catalytic activity of NHC catalysts in the enantioselective acylation of racemic alcohols, asymmetric intramolecular Stetter reactions, and intermolecular benzoin condensation of benzaldehyde derivatives. Herein, we report the development of novel high-performance NHC catalysts by remote substituent effects.

  • 新井 則義
    2024 年 82 巻 3 号 p. 234-245
    発行日: 2024/03/01
    公開日: 2024/03/06
    ジャーナル 認証あり

    Indoline-fused cyclic compounds constitute an important class of bioactive natural products, and they are also typical structural motifs in useful organic compounds exemplified by pharmaceuticals. Novel fused cyclic indoline frameworks attract a great deal of interest in bioactive screening for new pharmaceutical candidates. In conjunction with a recent trend in drug discovery, i.e., “escape from flatland” concept, conformationally constrained small-ring-fused compounds, such as cyclobutanes, have interested researchers in drug discovery due to the growing demand for less lipophilic conformationally restricted analogues of known scaffolds rather than the rigid aromatic compounds. To date, a number of synthetic methods have been reported for indoline derivatives fused with 5- or 6-membered ring, whereas those that contain a cyclobutane ring are much less explored. The photochemical [2+2] cycloaddition reaction is one of the most popular and facile methods of constructing 4-membered cyclic compounds. Though the reaction between 1-acylindoles and substituted ethenes is known for decades, several issues remains to be improved, including regio- or stereoselectivity and functional group transformability. We have developed photochemical [2+2] cycloaddition reactions of 1- or 3-(ω-allenyl) indole derivatives that give a variety of methylenecyclobutane-fused indoline frameworks. We newly found that 3’,4’-dimethylacetophenone (diMeOAP) acts as a quite effective photosensitizer in this kind of reaction. The 3’,4’-diMeOAP-sensitized photoreaction was successfully extended to preparation of cycloheptane-fused indolines and [2+2] cycloaddition of 7-azaindoles. The methylenecycloprapane derivatives turned out to be useful precursors for various ring-fused N-heterocyclic compounds via an epoxidation/skeletal rearrangement sequence.

  • 岩澤 哲郎
    2024 年 82 巻 3 号 p. 246-256
    発行日: 2024/03/01
    公開日: 2024/03/06
    ジャーナル 認証あり

    Described herein is synthesis of octacyclic C60 fragments, wherein twofold pentagons were fused into six hexagons of dibenzo[g,p]chrysenes (DBCs). Two kinds of archetypal skeletons have been created depending on the location of pentagons: One is a rigid bowl-shaped structure, and the other is a flexible non-planar framework. The key to success in both types lies in solution-phase synthesis, which was ascribed to multi-substituted DBCs having alkyl groups as a solubilizing agent and functional moieties as a reactive site that could be further converted. The solution-processable DBCs undertook conventional cyclization protocols, and enabled forming assembly of pentagons right beside hexagons beyond steric barrier. This account will outline the solution-compatible schemes that provide DBC-based synthesis of a new C60 fragmentary octacycle which we named Metelykene.

  • 大石 雄基, 井上 将彦
    2024 年 82 巻 3 号 p. 257-268
    発行日: 2024/03/01
    公開日: 2024/03/06
    ジャーナル 認証あり

    Organic fluorescent dyes are widely used in fields ranging from materials science to bio-science. On the other hand, these dyes often exhibit low solubilities in water and photo-stabilities, which sometimes cause difficulties in their practical use. To solve these problems, we have developed rotaxane-type fluorescence dyes, in which polycyclic aromatic hydrocarbons are irreversibly encapsulated with cyclodextrins. For example, the [3]rotaxanes encapsulating only one pyrene core show not only enough water-solubility and photo-durability but also high emission efficiency in various solvents and even in solid state because the fluorescent core is shielded from the external environment. The [4]rotaxanes encapsulating two pyrene or perylene cores emitted excimer-emission-based circular polarized luminescence with large dissymmetry factors. Furthermore, we succeeded in synthesizing [5]rotaxanes with various emission colors ranging from blue to red by adopting a cooperative capture strategy using cucurbit[6]uril in high yields. The obtained [5]rotaxane-type fluorescent dyes show desirable photo-physical and chemical properties in a manner much like the above [3] and [4]rotaxane-type dyes.

  • 田中 一生, 権 正行, 伊藤 峻一郎
    2024 年 82 巻 3 号 p. 269-278
    発行日: 2024/03/01
    公開日: 2024/03/06
    ジャーナル 認証あり

    The new strategy for modulating the energy levels of conjugated molecules without extending the π-conjugated system is described. In the distribution of frontier molecular orbitals (FMOs) which can be depicted with quantum calculation, when one of FMOs is distributed on the skeletal carbon, each of them is defined as the isolated highest occupied molecular orbital (HOMO) or the lowest unoccupied molecular orbital (LUMO). By substituting skeletal carbon to nitrogen (aza-substitution) at the isolated FMO, we found that efficient and selective lowering of the energy level of one of FMOs is realized. In this review, we explain recent progresses on the developments of near-infrared (NIR) light-absorbing and/or emitting materials based on the selective lowering of LUMO energy levels through the aza-substitution at the isolated LUMO. Initially, the representative examples on the regulation of energy levels of FMOs are illustrated with azaphenalene derivatives. Next, aggregation-induced emission (AIE) and/or crystallization-induced emission (CIE)-active complexes with longer wavelength emission are explained. Furthermore, the series of conjugated polymers having NIR-luminescent properties were obtained. The mechanism and applications for advanced optical materials are described. We show here that aza-substitution at the isolated LUMO is a powerful strategy for controlling the energy level of conjugated systems and creating superior functional materials.

Review de Debut
ラウンジ
十字路
感動の瞬間
feedback
Top