Nickel-Catalyzed C[BOND]H Arylation of Azoles with Haloarenes: Scope, Mechanism, and Applications to the Synthesis of Bioactive Molecules

Authors

  • Takuya Yamamoto,

    1. Department of Chemistry, Graduate School of Science, Nagoya University, Chikusa, Nagoya 464-8602 (Japan), Fax: (+81) 52-788-6098
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  • Kei Muto,

    1. Department of Chemistry, Graduate School of Science, Nagoya University, Chikusa, Nagoya 464-8602 (Japan), Fax: (+81) 52-788-6098
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  • Masato Komiyama,

    1. Pharmaceutical Development Research Laboratories, Teijin Pharma Limited, 3-2, Asahigaoka 4-chome, Hino, Tokyo 191-8512 (Japan)
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  • Dr. Jérôme Canivet,

    1. Department of Chemistry, Graduate School of Science, Nagoya University, Chikusa, Nagoya 464-8602 (Japan), Fax: (+81) 52-788-6098
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  • Dr. Junichiro Yamaguchi,

    1. Department of Chemistry, Graduate School of Science, Nagoya University, Chikusa, Nagoya 464-8602 (Japan), Fax: (+81) 52-788-6098
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  • Prof. Dr. Kenichiro Itami

    Corresponding author
    1. Department of Chemistry, Graduate School of Science, Nagoya University, Chikusa, Nagoya 464-8602 (Japan), Fax: (+81) 52-788-6098
    • Department of Chemistry, Graduate School of Science, Nagoya University, Chikusa, Nagoya 464-8602 (Japan), Fax: (+81) 52-788-6098
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Abstract

Novel nickel-based catalytic systems for the C[BOND]H arylation of azoles with haloarenes and aryl triflates have been developed. We have established that Ni(OAc)2/bipy/LiOtBu serves as a general catalytic system for the coupling with aryl bromides and iodides as aryl electrophiles. For couplings with more challenging electrophiles, such as aryl chlorides and triflates, the Ni(OAc)2/dppf (dppf=1,1′-bis(diphenylphosphino)ferrocene) system was found to be effective. Thiazoles, benzothiazoles, oxazoles, benzoxazoles, and benzimidazoles can be used as the heteroarene coupling partner. Upon further investigation, we discovered a new protocol for the present coupling using Mg(OtBu)2 as a milder and less expensive alternative to LiOtBu. Attempts to reveal the mechanism of this nickel-catalyzed heterobiaryl coupling are also described. This newly developed methodology has been successfully applied to the syntheses of febuxostat (a xanthine oxidase inhibitor that is effective for the treatment of gout and hyperuricemia), tafamidis (effective for the treatment of TTR amyloid polyneuropathy), and texaline (a natural product having antitubercular activity).

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