The Synthesis of a New Class of Chiral Pincer Ligands and Their Applications in Enantioselective Catalytic Fluorinations and the Nozaki–Hiyama–Kishi Reaction

Authors

  • Dr. Qing-Hai Deng,

    1. Anorganisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 270, 69120 Heidelberg (Germany), Fax: (+49) 6221-545-609
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  • Prof. Dr. Hubert Wadepohl,

    1. Anorganisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 270, 69120 Heidelberg (Germany), Fax: (+49) 6221-545-609
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  • Prof. Dr. Lutz H. Gade

    Corresponding author
    1. Anorganisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 270, 69120 Heidelberg (Germany), Fax: (+49) 6221-545-609
    • Anorganisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 270, 69120 Heidelberg (Germany), Fax: (+49) 6221-545-609
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Abstract

A new class of chiral tridentate N-donor pincer ligands, bis(oxazolinylmethylidene)isoindolines (boxmi), was synthesized in three steps starting from readily available phthalimides. Their reaction with ethyl (triphenylphosphoranylidene)acetate by means of a key-step Wittig reaction gave the ligand backbones, which were condensed with amino alcohols and then cyclized to obtain the corresponding ligands. These ligands were subsequently applied in the nickel(II)-catalyzed enantioselective fluorination of oxindoles and β-ketoesters to obtain the corresponding products with enantioselectivities of up to >99 % ee and high yields. Application of the chiral pincer ligands in the chromium-catalyzed enantioselective Nozaki–Hiyama–Kishi reaction of aldehydes gave the corresponding alcohols with an optimal enantioselectivity of 93 %.

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