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 4
Displaying 1-11 of 11 articles from this issue
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Preface
Reviews and Accounts
  • Novel Cyclizations of Enynes via Ruthenacyclopentene Intermediate
    Nozomi Saito, Miwako Mori, Yoshihiro Sato
    2010 Volume 68 Issue 4 Pages 348-358
    Published: 2010
    Released on J-STAGE: May 21, 2010
    DOIhttps://doi.org/10.5059/yukigoseikyokaishi.68.348
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    Three novel ruthenium–catalyzed cyclizations of enynes were developed. In each cyclization, a ruthenacyclopentene derived from enyne and Cp*RuCl(cod) is a common intermediate. When an enyne having an alkyl, an ester or a formyl group on an alkyne was reacted with Cp*RuCl(cod) under ethylene gas, ethylene was inserted into ruthenium–sp2 carbon bond of the ruthenacyclopentene to afford ruthenacycloheptene, and β–hydrogen elimination followed by reductive elimination occurred to give a cyclic compound having a diene moiety. When an acyl group was placed on the alkyne, the carbonyl oxygen would coordinate to the ruthenium metal of ruthenacyclopentene to produce ruthenium carbene, which would react with ethylene to give a cyclic compound having a cyclopropane ring on the substituent. On the other hand, when the substituent on the alkene was ω–pentene, insertion of an alkene part into ruthenacyclopentene followed by reductive elimination gave a tricyclic compound via a ruthenium–catalyzed [2+2+2]cocyclization of diene and an alkyne.
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  • Boryl Anion: Syntheses and Properties of Novel Borylmetals
    Makoto Yamashita, Kyoko Nozaki
    2010 Volume 68 Issue 4 Pages 359-369
    Published: 2010
    Released on J-STAGE: May 21, 2010
    DOIhttps://doi.org/10.5059/yukigoseikyokaishi.68.359
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    This account reviews our recent research on chemistry of “boryl anion”. Boryl anions can be classified with their metallic counterpart, such as Li, Mg, Cu, and Zn in a similar manner to the classification of carbanion. Syntheses and characterizations of boryllithium compounds have been achieved by using bulky substituents to prevent a dimerization of a boryl radical intermediate and nitrogen–containing heterocycle to gain an electronic stabilization. Transmetallation of boryllithium afforded a series of borylmetals having Mg, Zn, Cu, Ag, Au, Ti, or Hf. Some of these borylmetals can be regarded as a boryl anion species possessing a nucleophilic character towards organic electrophiles. Detailed analyses of group 11 borylmetal species showed a strong trans influence of boryl ligand. Borylhafnium complex could be utilized as a catalyst precursor for olefin polymerization.
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  • Chirality Organization of Peptide Conjugated Molecules in Bioorganometallic Chemistry
    Toshiyuki Moriuchi, Toshikazu Hirao
    2010 Volume 68 Issue 4 Pages 370-377
    Published: 2010
    Released on J-STAGE: May 21, 2010
    DOIhttps://doi.org/10.5059/yukigoseikyokaishi.68.370
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    Ferrocene–peptide bioconjugates and urea–peptide bioconjugates are designed to induce chirality–organized structures in both solid and solution states. The ferrocene organometallic scaffold is found to serve as a reliable central reverse–turn unit for the construction of protein secondary structures via intramolecular hydrogen bonding, wherein the attached dipeptide strands are regulated in the appropriate dimensions. The configuration and sequence of the amino acids play an important role in the construction of the chirality–organized bio–inspired systems under controlled hydrogen bonding. Another noteworthy feature of ferrocene–peptide bioconjugates is their strong tendency to self–assemble through contribution of available hydrogen bonding donors in a solid state. Also, the complexation of ferrocene–peptide bioconjugates with palladium (II) compounds is demonstrated not only to stabilize the chirality conformational regulation but also to induce conformational regulation of the dipeptide chain through complexation and chirality organization based on intramolecular hydrogen bonding. Introduction of two dipeptide chains bearing the C–terminal pyridyl moiety (–L–Ala–L–Pro–NH–2–Py) into the urea scaffold is performed to form a hydrogen–bonded duplex, wherein a shuttle–like molecular dynamics based on recombination of the hydrogen bonds is observed in a solution state.
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  • Construction of Nano–biomolecular Systems by Self–assembly of DNAs and Peptides
    Kazunori Matsuura
    2010 Volume 68 Issue 4 Pages 378-386
    Published: 2010
    Released on J-STAGE: May 21, 2010
    DOIhttps://doi.org/10.5059/yukigoseikyokaishi.68.378
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    In biological system, various nano–assemblies are formed by self–assembly of proteins with high symmetric ternary structures. For example, dodecahedral internal skeleton of tomato bushy stunt virus is self–assembled from C3–symmetric β–sheet subunits. Inspired by such self–assembly process, we have developed a novel strategy for construction of spherical assemblies consisting of biomacromolecules such as DNA and peptides. DNA three–way junctions bearing self–complementary sticky–ends were self–assembled into nanometer to micrometer sized spherical structures depending on the concentration. The three–way component design was extended to the design of the artificial C3–symmetric conjugate which contains three β–sheet–forming peptides FKFEFKFE. Radial–type Trigonal–FKFE self–assembled into nanocapsules with the size of 20 nm. In contrast, wheel–type Trigonal–FKFE self–assembled into nanofibers with uniform width (3 nm). Recently, we designed T–shaped C3–symmetric peptide conjugate Trigonal–glutathiones (TG). TG self–assembled into soft nanospheres with the size of about 100—250 nm, whose size was little affected by the concentration.
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  • Synthetic Studies on Bacilosarcins A and B, and Related Natural Products
    Masaru Enomoto, Shigefumi Kuwahara
    2010 Volume 68 Issue 4 Pages 387-398
    Published: 2010
    Released on J-STAGE: May 21, 2010
    DOIhttps://doi.org/10.5059/yukigoseikyokaishi.68.387
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    The first total synthesis of two herbicidal natural products bacilosarcins A and B, the former of which incorporates a totally unprecedented heterobicyclic ring system and the latter contains a very rare heterecyclic structural motif, has been accomplished. The irregular ring systems in bacilosarcins A and B were constructed in very simple manners by means of an Amadori–type N–alkylation reaction as well as by taking advantage of the thermodynamic stability of the targeted rings. The total synthesis of PM–94128 and Y–05460M–A, cytotoxic natural products of microbial origin, has also been accomplished by a concise nine–step sequence from L–leucine and L–valine, respectively. The first synthesis of Y–05460M–A enabled its stereochemical determination.
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  • Development of Carbazole Dyes for Efficient Molecular Photovoltaics
    Nagatoshi Koumura, Kohjiro Hara
    2010 Volume 68 Issue 4 Pages 399-408
    Published: 2010
    Released on J-STAGE: May 21, 2010
    DOIhttps://doi.org/10.5059/yukigoseikyokaishi.68.399
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    Dye–Sensitized Solar Cells (DSSCs), which are one of the promising molecular photovoltaics, have been attracting considerable attention because the unconventional solar cells exhibit high performance and have the potential for low–cost production. The photosensitizer is one of the most important components influencing solar–cell performance, because the choice of sensitizer determines the photoresponse range of the DSSC and initiates the primary steps of photon absorption and the subsequent electron transfer process. Generally, Ru–polypyridyl–complex sensitizers, developed by Prof. Grätzel and co–workers, have been employed for efficient DSSCs. In addition to conventional Ru–complex sensitizers, metal–free organic dyes have also been utilized as sensitizers in DSSCs, and the photovoltaic performance of DSSCs based on organic–dye sensitizers has been improved relative to earlier studies of DSSCs with organic dyes. We have designed and synthesized alkyl–functionalized carbazole dyes to improve both solar–cell performance and long–term stability of the solar cells. Here, we report detailed synthesis of carbazole dyes, photovoltaic performance and long–term stability of DSSCs based on these carbazole dyes.
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