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Palladium(0)-Catalyzed Intramolecular [2+2+2] Alkyne Cyclotrimerizations with Electron-Deficient Diynes and Triynes

Authors

  • Yoshihiko Yamamoto Dr.,

    1. Department of Molecular Design and Engineering Graduate School of Engineering Nagoya University Chikusa, Nagoya 464-8603, Japan, Fax: (+81) 52-789-3205
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    • Current address: Department of Applied Chemistry Graduate School of Engineering, Nagoya University Chikusa, Nagoya 464-8603 (Japan)

  • Asako Nagata,

    1. Department of Molecular Design and Engineering Graduate School of Engineering Nagoya University Chikusa, Nagoya 464-8603, Japan, Fax: (+81) 52-789-3205
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  • Hitomi Nagata,

    1. Department of Molecular Design and Engineering Graduate School of Engineering Nagoya University Chikusa, Nagoya 464-8603, Japan, Fax: (+81) 52-789-3205
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  • Yoji Ando,

    1. Department of Molecular Design and Engineering Graduate School of Engineering Nagoya University Chikusa, Nagoya 464-8603, Japan, Fax: (+81) 52-789-3205
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  • Yasuhiro Arikawa Dr.,

    1. Research Center for Materials Science, and Department of Chemistry Graduate School of Science Nagoya University Chikusa, Nagoya 464-8602, Japan
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  • Kazuyuki Tatsumi Prof. Dr.,

    1. Research Center for Materials Science, and Department of Chemistry Graduate School of Science Nagoya University Chikusa, Nagoya 464-8602, Japan
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  • Kenji Itoh Prof. Dr

    1. Department of Molecular Design and Engineering Graduate School of Engineering Nagoya University Chikusa, Nagoya 464-8603, Japan, Fax: (+81) 52-789-3205
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Abstract

In the presence of 2.5 mol % of [Pd2(dba)3] (dba=dibenzylideneacetone) and 5 mol % of PPh3, nearly equimolar amounts of dimethyl nona-2,7-diyne-1,9-dioate derivatives (diyne diesters) and dialkyl acetylenedicarboxylates were allowed to react in toluene at 110 °C to afford [2+2+2] cycloadducts in moderate-to-good yields. Similarly, dimethyl trideca-2,7,12-triyne-1,13-dioate derivatives (triyne diesters) were catalytically transformed into phthalic acid ester analogues in excellent yields. To gain insight into the mechanism of these intramolecular alkyne cyclotrimerizations, stoichiometric reactions of [Pd2(dba)3] with a diyne diester and a triyne diester bearing ether tethers were conducted in acetone at room temperature to furnish an oligomeric bicyclopalladacyclopentadiene and a Pd0 triyne complex, respectively. The structures of these novel complexes were unequivocally determined by Xray structure analysis. The isolated triyne complex was heated at 50 °C or treated with PPh3 in acetone at room temperature to afford the arene product. Furthermore, the same complex catalyzed the triyne cyclization with or without PPh3.

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