Sakae Sugiyama

Tokyo Institute of Technology, Edo, Tōkyō, Japan

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Publications (5)19.16 Total impact

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    ABSTRACT: We have developed a one-pot, four-component Suzuki–Miyaura coupling for the synthesis of thiophene-based donor–π-bridge–acceptor (D–π–A) dyes for dye-sensitized solar cells. Two D–π–A dyes, 19 and 20, retaining 3,4-ethylenedioxythiophene (EDOT) beside a cyanoacrylic acid moiety, and one D–π–A dye 21 without EDOT (reference compound) were rapidly synthesized in accordance with the developed procedure. The measurement of the absorption spectra and the electrochemical properties of synthesized dyes, and the photovoltaic properties of solar cells that were prepared using the synthesized dyes 19–21, revealed that the dyes retaining only one EDOT beside a cyanoacrylic acid moiety would exert a high Jsc.
    Tetrahedron 11/2014; 70(45):8690–8695. DOI:10.1016/j.tet.2014.09.039 · 2.64 Impact Factor
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    ABSTRACT: The creation of organic dyes with excellent high power conversion efficiency (PCE) is important for the further improvement of dye-sensitized solar cells. We wish to describe the rapid synthesis of a 112-membered donor-π-acceptor dye library by a one-pot procedure, evaluation of PCEs, and elucidation of structure-property relationships. No obvious correlations between ε, and the η were observed, whereas the HOMO and LUMO levels of the dyes were critical for η. The dyes with a more positive EHOMO , and with an ELUMO <-0.80 V, exerted higher PCEs. The proper driving forces were crucial for a high Jsc , and it was the most important parameter for a high η. The above criteria of EHOMO and ELUMO should be useful for creating high PCE dyes; nevertheless, that was not sufficient for identifying the best combination of donor, π, and acceptor blocks. Combinatorial synthesis and evaluation was important for identifying the best dye.
    Chemistry - A European Journal 08/2014; 20(34). DOI:10.1002/chem.201402093 · 5.73 Impact Factor
  • Sakae Sugiyama · Shinichiro Fuse · Takashi Takahashi
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    ABSTRACT: A resorcylic acid lactone (RAL) framework was constructed based on a three-component coupling approach. The key step was the intermolecular alkylation of a protected cyanohydrin with an aromatic scaffold, and the subsequent carbonylative esterification of the aryl iodide with an alcohol. This sequence allowed the rapid assembly of three components without extra protection/deprotection steps. This synthetic strategy enables the ketone at the 2′ position to be masked as a protected cyanohydrin during the ester formation, thus avoiding an undesired isocoumarin formation. This method should be widely applicable to the synthesis of various types of RAL frameworks.
    Tetrahedron 09/2011; 67(35):6654-6658. DOI:10.1016/j.tet.2011.05.023 · 2.64 Impact Factor
  • Shinichiro Fuse · Sakae Sugiyama · Takashi Takahashi
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    ABSTRACT: A combination of chemoselective Pd-catalyzed carbonylative esterification of o-iodobromobenzene derivative (I) with Pd-catalyzed functionalization (amination, cross coupling or carbonylative esterification) and ring closing metathesis reaction is successfully applied in the synthesis of resorcylic acid lactone frameworks.
    Chemistry - An Asian Journal 12/2010; 5(12):2459-62. DOI:10.1002/asia.201000534 · 4.59 Impact Factor
  • Seiji Kamioka · Sakae Sugiyama · Takashi Takahashi · Takayuki Doi
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    ABSTRACT: Synthesis and structure elucidation of optically active tri-, tetra-, and penta-azamacrocycles having 4-methoxyphenyl pendants are described. Regioselective ring opening of a nosylaziridine with secondary benzyl amines was repeatedly performed to afford the cyclization precursors. Intramolecular N-alkylation of N-(omega-haloalkyl) nosylamide provided tri-, tetra-, and penta-azamacrocycles. On the basis of our study of the tetra-azamacrocycle previously elucidated by X-ray single-crystal analysis and in solution by NMR analysis, we conclude that the tri-azamacrocycle does not mainly have a vase-type conformation because of the steric hindrance of the 4-methoxyphenyl groups but the penta-azamacrocycle has a vase-type conformation in CDCl(3) and in CD(2)Cl(2). The vase-type conformation of the penta-azamacrocycle is, however, not as much stable as that observed in the tetra-azamacrocycle because conformational flexibility of the penta-azamacrocycle was observed in deuterated benzene.
    Organic & Biomolecular Chemistry 04/2010; 8(11):2529-36. DOI:10.1039/c001228a · 3.56 Impact Factor