Comparison of dppf‐Supported Nickel Precatalysts for the Suzuki–Miyaura Reaction: The Observation and Activity of Nickel(I) |
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Authors: | Dr. Louise M. Guard Megan Mohadjer Beromi Prof. Gary W. Brudvig Prof. Nilay Hazari Dr. David J. Vinyard |
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Affiliation: | The Department of Chemistry, Yale University, P.O. Box 208107, New Haven, CT 06520 (USA) |
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Abstract: | Ni‐based precatalysts for the Suzuki–Miyaura reaction have potential chemical and economic advantages compared to commonly used Pd systems. Here, we compare Ni precatalysts for the Suzuki–Miyaura reaction supported by the dppf ligand in 3 oxidation states, 0, I and II. Surprisingly, at 80 °C they give similar catalytic activity, with all systems generating significant amounts of NiI during the reaction. At room temperature a readily accessible bench‐stable NiII precatalyst is highly active and can couple synthetically important heterocyclic substrates. Our work conclusively establishes that NiI species are relevant in reactions typically proposed to involve exclusively Ni0 and NiII complexes. |
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Keywords: | cross‐coupling homogeneous catalysis nickel reaction mechanism Suzuki– Miyaura coupling |
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