Journal of Synthetic Organic Chemistry, Japan
Online ISSN : 1883-6526
Print ISSN : 0037-9980
ISSN-L : 0037-9980
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Volume 74, Issue 7
Displaying 1-9 of 9 articles from this issue
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Preface
Reviews and Accounts
  • Design and Development of New Functional Units towards Single-Molecule Electronics
    Yutaka Ie, Yoshio Aso
    2016 Volume 74 Issue 7 Pages 676-688
    Published: July 01, 2016
    Released on J-STAGE: August 04, 2016
    DOIhttps://doi.org/10.5059/yukigoseikyokaishi.74.676
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    Single-molecule electronics have attracted a great deal of attention in terms of the bottom-up construction and ultimate miniaturization of electronics. Development of novel materials for this application has become an active area of research. We have designed and synthesized new π-conjugated systems for the use in “anchor” and “insulated molecular wire” units, which are essential components of single-molecule electronics. The tetraphenylmethane-based tripodal structures with anchoring functional groups were developed to function as anchor units, that is, these molecules fulfill not only the electronic communication between electrodes and molecules but also robust attachment to electrodes with controlling the molecular orientation. Structurally well-defined oligothiophenes were utilized as a key framework of molecular wires. The combination of cyclopenta [c] thiohene with orthogonally introduced bulky substituents accomplished the encapsulation of derived oligothiophene backbones without disturbing effective conjugation, leading to the construction of insulated molecular wires.
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  • Total Synthesis of Natural Antifouling Products
    Taiki Umezawa, Keisuke Nishikawa, Tatsufumi Okino, Fuyuhiko Matsuda
    2016 Volume 74 Issue 7 Pages 689-699
    Published: July 01, 2016
    Released on J-STAGE: August 04, 2016
    DOIhttps://doi.org/10.5059/yukigoseikyokaishi.74.689
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    Biofouling is adverse growth of marine organisms on manmade submersible structures such as ships’ hulls and cause significant economic and environmental problems. As a fouling inhibitor, tributyltin (TBT) has been widely used for controlling the sessile organisms since the early 1960s. Unfortunately, serious pollution of the marine environment due to the deleterious effect of TBT prompted the International Maritime Organization (IMO) to call in 2008 for a ban on the use of tributyltin (TBT) on ships. Since marine invertebrates prevent settlement of other benthic marine organisms through the use of natural substances with antifouling properties without causing serious environmental problems, natural antifouling products with good antifouling properties but without biocidal properties have attracted considerable attention. Among these, 10-isocyano-4-cadinene and omaezallene show promise as lead compounds for the development of new environmentally friendly antifouling agents due to its potent antifouling activity against the cypris larvae of the barnacle Amphibalanus amphitrite and low toxicity. 10-Isocyano-4-cadinene, an isocyanosesquiterpene, was isolated from nudibranchs of the family Phyllidiidae. On the other hand, omaezallene is a bromoallene-containing C15-acetogenin isolated from the red alga Laurencia sp. Herein, we wish to describe our research on the isolations, structure elucidations, total syntheses, and evaluation of the antifouling activities of the natural products and their derivatives. The absolute configurations of the natural products were unambiguously established through our asymmetric total syntheses.
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  • Unrecognized Reactivity of N-Alkyl Unsaturated Imines: Synthetic Application and Biological Functions
    Ambara R. Pradipta, Ayumi Tsutsui, Katsunori Tanaka
    2016 Volume 74 Issue 7 Pages 700-709
    Published: July 01, 2016
    Released on J-STAGE: August 04, 2016
    DOIhttps://doi.org/10.5059/yukigoseikyokaishi.74.700
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    Imines are among the most ubiquitous species in organic and bioorganic chemistry; however, the reactivities of N-alkyl unsaturated imines have not been thoroughly explored due to their instability profiles. We describe the novel reactivity of the N-alkyl-unsaturated imines derived from substituted aldehydes, aminoalcohol or diamine, and paraformaldehyde to produce 2,6,9-triazabicyclo [3.3.1] nonanes, 1,5-diazacyclooctanes, hexahydropyrimidines and 1,3,5-triazacyclooctanes through a formal [4+4], [4+2] and [4+2+2] cycloaddition reaction. When using the chiral aminoalcohol, the iminocycloaddition reaction proceeded in a stereocontrolled manner. The reaction products were successfully transformed via simple functional group manipulations to the variously substituted chiral 1,3-diamines, which could not be simply accessed by the other methods. Furthermore, we synthetically demonstrated that eight-membered heterocycles, namely, 2,6,9-triazabicyclo [3.3.1] nonanes and 1,5-diazacyclooctanes, are the exclusive products of the reaction of acrolein with biologically relevant amines, e.g., polyaimes. These compounds are produced in much higher amounts and efficiencies than the acrolein biomarker in current use. Our results not only indicate that eight-membered heterocycles may potentially be used as new biomarkers, but also strongly suggest the involvement of these heterocycles in various important biological phenomena, e.g., an acrolein-mediated mechanism underlying oxidative stress or inhibitory effects of amyloid peptide fibrillization.
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  • Synthesis of Chiral Polymer Catalysts and Their Application to Asymmetric Reactions
    Shinichi Itsuno
    2016 Volume 74 Issue 7 Pages 710-719
    Published: July 01, 2016
    Released on J-STAGE: August 04, 2016
    DOIhttps://doi.org/10.5059/yukigoseikyokaishi.74.710
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    Novel synthesis of chiral polymers containing catalytic active sites is described. Precise control of the chiral polymer structure gives specific chiral microenvironment suitable for an asymmetric catalysis. These polymeric chiral catalysts often show higher enantioselectivities in asymmetric reactions compared with the corresponding original low-molecular-weight catalysts. Many of chiral organocatalysts consist of ionic structure, which act as phase transfer catalysts. Ionic bond formation reaction such as quaternary ammonium sulfonate formation was used for the synthesis of chiral polymers. Typical reaction between chiral bis(quaternary ammonium halide) and disodium disulfonate gives chiral ionic polymers. This simple chiral polymer synthesis enable us to prepare various kinds of polymeric chiral phase transfer catalysts. Cinchona alkaloids and their derivatives have been vigorously developed as excellent chiral catalysts. Polymerization of cinchona derivatives have been described. Not only chiral ionic polymers, chiral polyethers and polythioethers have also been synthesized from cinchona alkaloid. Mizoroki-Heck polymerization of cinchona alkaloid was also established. These cinchona polymers exhibited powerful tool in asymmetric synthesis. Another important organocatalyst is chiral imidazolidinones developed by MacMillan. The polymerization of MacMillan catalysts was investigated. Highly enantioselective MacMillan polymers have been developed. Some chirally modified transition metal catalysts have been polymerized to give chiral polymer catalysts. Asymmetric transfer hydrogenation of imines was demonstrated.
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  • Development of Asymmetric Cycloaddition Reaction Using Amino Alcohol and its Derivative as an Organocatalyst
    Hiroto Nakano, Jun Kumagai, U. V. Subba Reddy, Chigusa Seki, Yuko Okuy ...
    2016 Volume 74 Issue 7 Pages 720-731
    Published: July 01, 2016
    Released on J-STAGE: August 04, 2016
    DOIhttps://doi.org/10.5059/yukigoseikyokaishi.74.720
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    The design of a chiral organocatalyst is very important for achievement of a high optical purity in a catalytic asymmetric reaction. Recently, we developed various chiral β-amino alcohol organocatalysts. These organocatalysts showed high levels of catalytic activity in the asymmetric Diels-Alder (DA) reactions of some dienes with dienophiles and 1,3-dipolar cycloaddition of some nitrones with α,β-unsaturated aldehydes, respectively. Especially, β-amino alcohols worked as organocatalyst in the DA reaction of 1,2-dihydropyridines with acroleins to afford the useful synthetic intermediate of Tamiflu. The review summarizes these our studies.
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Review de Debut
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