Synthesis of 1,2-Bis(2-aryl-1H-indol-3-yl)ethynes via 5-exo-Digonal Double Cyclization Reactions of 1,4-Bis(2-isocyanophenyl)buta-1,3-diyne with Aryl Grignard Reagents

Rino Ishikawa, Ryosuke Iwasawa, Yuichiro Takiyama, Tomokazu Yamauchi, Tetsuo Iwanaga, Makoto Takezaki, Motonori Watanabe, Naozumi Teramoto, Toshiaki Shimasaki, Mitsuhiro Shibata

    研究成果: Contribution to journalArticle査読

    10 被引用数 (Scopus)

    抄録

    New π-conjugated 1,2-bis(2-aryl-1H-indol-3-yl)ethynes 1a-j having various substituents on the two aryl groups were efficiently synthesized via unusual 5-exo-digonal double isocyanide-acetylene cyclization reactions of 1,4-bis(2-isocyanophenyl)buta-1,3-diyne 3 and aryl Grignard reagents (R-MgBr, R = C6H5 (1a), 4-H3CC6H4 (1b), 2-H3CC6H4 (1c), 3-MeOC6H4 (1d), 3-(CH3)2NC6H4 (1e), 4-F3CC6H4 (1f), 4-FC6H4 (1g), 3-FC6H4 (1h), 4-PhOC6H4 (1i), and 2-Naph (1j)) in 19-85% yields. The UV-vis spectra were rationalized in detail using time-dependent DFT and single point calculations. The fluorescence emission peaks for 1a-j were observed at around 450 nm. Especially for 1f and 1j, those spectra displayed broad emission bands and relatively large Stokes shifts (3977-4503 cm-1), indicating the contribution of an intramolecular charge transfer. The absolute quantum yields (0.50-0.62) of 1a-j were higher than those of parent 8 (0.19) and 2-phenyl-1H-indole (0.11). The electrochemical features for 1a-j were investigated by cyclic voltammetry. The frontier molecular orbital levels for 1a-j were estimated based on the combination of oxidation potentials, UV-vis, and DFT calculated data. The structural property of 1,2-bis(2-phenyl-1H-indol-3-yl)ethyne 1a was characterized by several spectroscopic methods and finally determined by X-ray analysis of a single crystal of 1a recrystallized from ethyl acetate. The structural features of 1a-j were also supported by DFT calculations.

    本文言語英語
    ページ(範囲)652-663
    ページ数12
    ジャーナルJournal of Organic Chemistry
    82
    1
    DOI
    出版ステータス出版済み - 1 6 2017

    All Science Journal Classification (ASJC) codes

    • Organic Chemistry

    フィンガープリント 「Synthesis of 1,2-Bis(2-aryl-1H-indol-3-yl)ethynes via 5-exo-Digonal Double Cyclization Reactions of 1,4-Bis(2-isocyanophenyl)buta-1,3-diyne with Aryl Grignard Reagents」の研究トピックを掘り下げます。これらがまとまってユニークなフィンガープリントを構成します。

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