Journal of Synthetic Organic Chemistry, Japan
Online ISSN : 1883-6526
Print ISSN : 0037-9980
ISSN-L : 0037-9980
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Volume 67, Issue 6
Displaying 1-10 of 10 articles from this issue
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Preface
Reviews and Accounts
  • Recent Progress in Asymmetric Allylic Substitutions Catalyzed by Transition Metal Complexes
    Kiyotaka Onitsuka
    2009 Volume 67 Issue 6 Pages 584-594
    Published: June 01, 2009
    Released on J-STAGE: April 07, 2011
    DOIhttps://doi.org/10.5059/yukigoseikyokaishi.67.584
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    Asymmetric allylic substitution catalyzed by an organometallic complex is a powerful method to create carbon-carbon and carbon-heteroatom bonds with high enantioselectivity, and is often applied to total syntheses of biologically active organic molecules. The reaction via a symmetrically substituted π-allylpalladium intermediate has been widely studied using a variety of chiral ligands. However, the reaction of unsymmetrically substituted allylic compounds is still a challenging research subject, because nucleophilic attack generally takes place at the less hindered allylic carbon giving a liner product in the reaction of monosubstituted allylic substrate with palladium catalysts. Recently, other transition metal complexes have shown high potential in this type of reactions, in which a branched isomer is obtained as a main product by the substitution at the hindered allylic carbon. This review focuses on the recent progress in the asymmetric allylic substitutions of unsymmetrically substituted allylic compounds producing branched products with high regio- and enantioselectivities.
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  • Metalloporphyrins and Phthalocyanines as Efficient Lewis Acid Catalysts with a Unique Reaction-Field
    Toshikatsu Takanami, Kohji Suda
    2009 Volume 67 Issue 6 Pages 595-605
    Published: June 01, 2009
    Released on J-STAGE: April 07, 2011
    DOIhttps://doi.org/10.5059/yukigoseikyokaishi.67.595
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    Metalloporphyrin complexes, such as Cr(TPP)X, Fe(TPP)X, and Yb(TPP)X, work as an efficient Lewis acid catalyst with a unique reaction-field that can promote the regio- and stereoselective rearrangement of epoxides to carbonyl compounds. Compared to other Lewis acid reagents and catalysts reported so far, these porphyrin-based catalysts have several advantages as follows: (1) These catalysts are stable crystalline solids more convenient to handle; (2) effective loading of the catalyst is generally less than 2% for the rearrangement; and (3) high yields and almost complete regio- and stereoselectivity can easily be achieved by these porphyrin-based catalysts.α,β-Epoxyketones are selectively transformed into the corresponding 1,2-diketones with a metalloporphyrin complex Fe(TPP)OTf. Ketones and aldehydes can selectively be prepared from the same di- and trisubstituted epoxide by the choice of Fe(III) and Cr(III) ions, respectively, as the central metal ion of the porphyrin catalysts. A metallophthalocyanine complex, Cr(TBPC)OTf is further efficient Lewis acid catalyst with an excellent reusability for the rearrangement of epoxides to aldehydes, thus the phthalocyanine-based catalyst enables the practical synthesis of enantioenriched aldehydes bearing a stereogenic quaternary carbon centre from optically active trisubstituted epoxides.
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  • Stereocontrol between Remote Atom Centers Using Chiral Acetals and its Application to Asymmetric Syntheses of Natural Products
    Hiromichi Fujioka, Yasuyuki Kita
    2009 Volume 67 Issue 6 Pages 606-617
    Published: June 01, 2009
    Released on J-STAGE: April 07, 2011
    DOIhttps://doi.org/10.5059/yukigoseikyokaishi.67.606
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    Intramolecular haloetherification of the ene acetals prepared from chiral non-racemic C2-symmetric diols and achiral 4-pentenal or 5-heptenal proceeded in diastereoselective manners to form two asymmetric centers. The reaction was applied to synthesize optically active 1,4- and 1,5-diols. On the other hand, intramolecular haloetherification of diene acetals proceeded in two different manners. The intramolecular haloetherification of the diene acetals, prepared from chiral hydrobenzoin and σ-symmetric cyclohexa-1,4-dienes, proceeded with one olefin in a diastereoselective manners and gave the compounds having one remained olefin. However, the reaction of the acyclic diene acetals, prepared from hydrobenzoin and σ-symmetric 1,7-dienes, occurred novel double haloetherification giving four newly formed chiral stereocenters. The developed reactions were applied to synthesize optically active natural products, a civet constituent, scyphostatin, (+)-Sch 642305, rublenolide and rubrynolide.
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  • Intramolecular Cycloaddition Between Allenyl π-Bond and Multiple Bond
    Shinji Kitagaki, Fuyuhiko Inagaki, Chisato Mukai
    2009 Volume 67 Issue 6 Pages 618-627
    Published: June 01, 2009
    Released on J-STAGE: April 07, 2011
    DOIhttps://doi.org/10.5059/yukigoseikyokaishi.67.618
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    Allene functionality has the potential to create interesting and useful reactions in organic synthesis. We have developed the following several novel cycloaddition reactions between allenyl π-bond and carbon-carbon multiple bond: (i) Intramolecular Pauson-Khand-type reaction of allene-alkyne substrates (allenynes) leading to construction of bicyclo[5.3.0]decadienone framework has been realized with the aid of Rh(I) catalyst under CO atmosphere. (ii) The allenynes were found to produce cycloheptene derivatives and/or bicyclo[5.2.0]nonadiene compounds depending on the substitution pattern at the allenic terminus under N2. (iii) Thermal[2+2]cycloaddition of allenynes was shown to be applicable to the construction of bicyclo[6.2.0]skeleton. (iv) We also found that the Pauson-Khand-type reaction of allene-alkenes (allenenes) and bisallenes resulted in the easy preparation of bicyclo[4.3.0]nonenone skeleton having an alkyl appendage at the ring juncture and bicyclo[6.3.0]undecadienone derivatives, respectively.
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  • Total Synthesis of Botcinolides and Botcinins; Determination of the Structure of Natural Products Isolated from Botrytis cinerea
    Hiroki Fukui, Isamu Shiina
    2009 Volume 67 Issue 6 Pages 628-642
    Published: June 01, 2009
    Released on J-STAGE: April 07, 2011
    DOIhttps://doi.org/10.5059/yukigoseikyokaishi.67.628
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    The first asymmetric total syntheses of botcinins A-F, homobotcinin E, botcinic acid, botcinic acid methyl ester, botcineric acid, and 3-O-acetylbotcinic acid methyl ester were achieved. The structures of these compounds have been unequivocally determined through their total syntheses and those of botcinin A, botcinin B, botcinin E, homobotcinin E, botcinic acid, botcinic acid methyl ester, botcineric acid, and 3-O-acetylbotcinic acid methyl ester are identified with the revised forms of the natural products formerly assumed to be 3-O-acetyl-2-epibotcinolide, 3-O-acetyl-2-epihomobotcinolide, 2-epibotcinolide, 2-epihomobotcinolide, botcinolide, 4-O-methylbotcinolide, homobotcinolide, and 3-O-acetyl-5-O-methylbotcinolide, respectively. It was further proved that the proposed nine-membered ring structure of 2-epibotcinolide is very unstable and the ineluctable translactonization easily occurred to form the corresponding γ-lactone.
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  • Direct Phenol Synthesis from Benzene and Oxygen on Supported Rhenium Catalysts
    Mizuki Tada, Yasuhiro Iwasawa
    2009 Volume 67 Issue 6 Pages 643-650
    Published: June 01, 2009
    Released on J-STAGE: April 07, 2011
    DOIhttps://doi.org/10.5059/yukigoseikyokaishi.67.643
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    Phenol is one of the most important chemicals in industry and it is produced from cumene process from benzene. Direct phenol synthesis from benzene and O2 is an alternative way to produce phenol efficiently. We have succeeded in preparing a HZSM-5-zeolite-supported Re catalyst, which was highly active and selective for direct phenol synthesis from benzene and O2 (steady-state reaction: 5.8% benzene conversion and 88% phenol selectivity, pulse reaction: 9.9% benzene conversion and 94% phenol selectivity) in the presence of NH3. The formation of active Re clusters, their structural change, and the role of NH3 which are relevant to the selective benzene oxidation were investigated.
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Review de Debut
Chemicals
Crossroad
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