Journal of Synthetic Organic Chemistry, Japan
Online ISSN : 1883-6526
Print ISSN : 0037-9980
ISSN-L : 0037-9980
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Volume 68, Issue 1
Displaying 1-10 of 10 articles from this issue
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Preface
Reviews and Accounts
  • Generation of Novel Nucleophilic Organometallic Species and Their Applications to Organic Synthesis
    Kazuhiko Takai
    2010 Volume 68 Issue 1 Pages 3-18
    Published: 2010
    Released on J-STAGE: March 02, 2010
    DOIhttps://doi.org/10.5059/yukigoseikyokaishi.68.3
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    Development of nucleophilic organometallic species plays an important role in organic synthesis, especially for construction of carbon skeletons. This account describes the following synthetic reactions with novel organometallic species: (1) Preparation of alkenylchromium reagents for chemoselective addition to aldehydes, (2) Generation of geminal dimetallic species of zinc and chromium for the Wittig-type olefination, (3) Preparation of tantalum-alkyne complexes and their synthetic use, (4) Activation and deactivation of zinc with a catalytic amount of lead, (5) Control of one-electron transfer and its application to sequential radical and anionic reactions, (6) Rhenium and manganese catalyzed-Barbier-type addition of aromatic compounds to aldehydes based on C-H bond activation. The account focuses on the background to the research and how the reactions were discovered.
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  • Solid-phase Catalysis/CD-HTS: A Powerful Technology Platform for Exploring Novel Asymmetric Catalysts
    Takayoshi Arai
    2010 Volume 68 Issue 1 Pages 19-32
    Published: 2010
    Released on J-STAGE: March 02, 2010
    DOIhttps://doi.org/10.5059/yukigoseikyokaishi.68.19
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    The catalytic synthesis of chiral molecules is of crucial importance in fine chemistry in order to ensure the supply of useful and valuable organic compounds. The importance of this research topic has stimulated chemists worldwide to develop numerous methods of asymmetric catalysis, although the process of developing new catalysts involves tedious effort even when modern methods are used. One way to overcome the time-consuming aspect of the process would be to use the technology of combinatorial chemistry for the discovery and optimization of catalysts. For efficient exploration of novel asymmetric catalysts using the combinatorial approach, a convenient technology of high-throughput screening (HTS) is required for analyzing both catalytic activity (chemical yield) and enantiomeric excess.
       With the aim of investigating novel asymmetric catalysts using a library of chiral ligands, we have developed a new high-throughput screening (HTS) by coupling a circular dichroism (CD) detection with a reaction on solid-phase catalysts. Using the “solid-phase catalysis/CD-HTS”, several kinds of new asymmetric catalysts were discovered including an imidazoline-aminophenol-Cu catalyst. A novel catalytic asymmetric Friedel-Crafts/Henry reaction was successfully developed by the imidazoline-aminophenol-Cu catalyst to construct three contiguous acyclic stereocenters.
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  • Syntheses of Heterocycles by Nickel-catalyzed Substitution Reaction
    -Development of [6-2+2] Reaction-
    Takuya Kurahashi, Seijiro Matsubara
    2010 Volume 68 Issue 1 Pages 33-40
    Published: 2010
    Released on J-STAGE: March 02, 2010
    DOIhttps://doi.org/10.5059/yukigoseikyokaishi.68.33
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    A new synthetic strategy for heterocyclic compounds with transition metal-catalyzed reaction was developed. It was demonstrated that carbonyl moiety in a cyclic compound is susceptible to nucleophilic attack of nickel(0) complex, which allows an intermolecular formal [4+2] cycloaddition to alkynes via decarbonylation, decaroxylation or elimination of ketone. A nickel-catalyzed decarbonylative cycloadditon of N-arylphthalimides with alkynes affords substituted isoquinolones. A decarbonylative cycloaddition of phthalic anhydrides to alkynes is also successfully demonstrated using a nickel catalyst in association with a Lewis acid as a co-catalyst. A carboamination of alkynes with isatoic anhydrides to form quinolones is also achieved by a nickel-catalyzed decarboxylative cycloaddition. It is also demonstrated that a cycloaddition of salicylic acid ketal to alkyne using a nickel catalyst forms chromones through an elimination of a ketone.
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  • Highly Reactive Bifunctional Chemical Catalysts for the Hydration of Nitriles
    Toshiyuki Oshiki, Isao Hyodo, Akinori Ishizuka
    2010 Volume 68 Issue 1 Pages 41-51
    Published: 2010
    Released on J-STAGE: March 02, 2010
    DOIhttps://doi.org/10.5059/yukigoseikyokaishi.68.41
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    New bifunctional chemical catalysts for the hydration of nitriles are described. cis-Ru(acac)2(PPh2py)2 exhibited high activity, with a turnover frequency of up to 20,900 (mol of amide)/((mol of catalyst)h). Newly synthesized iridium complexes bearing a PPh2py ligand have a 16e- square planar structure. The catalytic hydration of nitriles proceeded at 80 °C within few hours to give corresponding amides in almost quantitative yield. Moreover, the iridium complexes acted as a catalyst for the hydration under solvent-free conditions. In addition, new catalysts based on palladium nanoparticles for the hydration are described. Copper compounds containing oxygen atom acted as effective co-catalysts in the catalytic system.
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  • How to Conduct Photochromic Electrocyclization Stereoselectively
    Yasushi Yokoyama
    2010 Volume 68 Issue 1 Pages 52-63
    Published: 2010
    Released on J-STAGE: March 02, 2010
    DOIhttps://doi.org/10.5059/yukigoseikyokaishi.68.52
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    The development of highly diastereoselective photochromic compounds that our group has carried out in the past 15 years is described here. Observations by 1H NMR of the enantiomeric isomerization of helically chiral hexatriene moiety of a fulgide which undergoes photochemical 6π-electrocyclization are first described, followed by discussions on the optical resolution of a fulgide and diastereoselective photochromism of an (R)-binaphthol-modified fulgide. A new concept of diastereoselective photochromism has also been realized by using diarylethenes as the template. The concept consists of: (i) Allylic 1,3-strain and (ii) electronic and steric repulsions between the oxygen atoms on a substituent on the stereogenic carbon atom attached to the ring-closing carbon atom located at one terminal of the hexatriene moiety and the heteroatom on the second heteroaromatic ring. Finally, a general strategy to achieve extraordinarily high diastereoselectivity of up to 100:0 has been demonstrated by the introduction of dual chiral stereocontrolling substituents to diarylethenes.
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  • Chemistry of Phenalenyl-based Delocalized Singlet Biradicals
    Takashi Kubo, Akihiro Shimizu, Masayoshi Nakano, Kazuhiro Nakasuji
    2010 Volume 68 Issue 1 Pages 64-74
    Published: 2010
    Released on J-STAGE: March 02, 2010
    DOIhttps://doi.org/10.5059/yukigoseikyokaishi.68.64
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    Main issue described in this article is clarification of spin-spin interactions in delocalized singlet biradical species, especially co-existence of intra- and inter-molecular interactions. For the end, we designed and prepared some singlet biradical molecules thermodynamically stabilized by utilizing spin-delocalizing character of phenalenyl radical. These species were found to be stable in air and could be isolated in a crystalline form. X-ray crystallographic analysis revealed the abnormally short π-π contact between molecules, suggesting a strong intermolecular spin-spin interaction, even though the species had a strong intramolecular spin-spin interaction. Co-existence of both the interactions led to lower energy shift of HOMO-LUMO absorption bands in a solid state with respect to solution bands. These findings indicate that covalent bonding character is operative within and between molecules in molecular aggregates of delocalized singlet biradicals. This new aspect was supported by variable-temperature X-ray crystallography and reflectivity measurement on single crystals which had one-dimensional π-π chains of the delocalized singlet biradicals, and we concluded that the electronic structure of the 1-D chain could be represented by the Resonating Valence Bond model proposed by Pauling.
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Review de Debut
  • Recent Advances in Cross-Coupling Reaction Catalyzed by Iron Salts
    Keiji Mori
    2010 Volume 68 Issue 1 Pages 75-76
    Published: 2010
    Released on J-STAGE: March 02, 2010
    DOIhttps://doi.org/10.5059/yukigoseikyokaishi.68.75
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    Palladium-and nickel-catalyzed cross-coupling reactions are indispensable tool for organic synthesis. Despite the wide application profile of this methodology, the search for feasible alternatives of these catalysts is highly demanded from the practical viewpoints. Recently, iron catalysts, which are environmentally friendly and economical, are found to be applicable to various cross-coupling reactions, including both C-C and C-X (X = hetero atom) bond forming reactions. These reactions can be conducted with simple procedure under mild conditions and are compatible with a variety of functional groups in both reaction partners.
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Crossroad
Practice of Reaction Mechanism
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