University of Michigan, Department of Chemistry, 930 North University Avenue, Ann Arbor, Michigan 48109, United States.
J Am Chem Soc. 2015 Jul 1;137(25):8034-7. doi: 10.1021/jacs.5b04892. Epub 2015 Jun 16.
This communication describes the synthesis and reactivity of Ni(IV)(aryl)(CF3)2 complexes supported by trispyrazolylborate and 4,4'-di-tert-butylbipyridine ligands. We demonstrate that isolable Ni(IV) complexes can be accessed under mild conditions via the oxidation of Ni(II) precursors with S-(trifluoromethyl)dibenzothiophenium triflate as well as with diaryliodonium and aryl diazonium reagents. The Ni(IV) intermediates undergo high yielding aryl-CF3 bond-forming reductive elimination. These studies support the potential viability of Ni(IV) intermediates in nickel-catalyzed coupling reactions involving diaryliodonium and aryldiazonium electrophiles.
本通讯描述了由三吡唑基硼酸盐和 4,4'-二叔丁基联吡啶配体支持的 Ni(IV)(芳基)(CF3)2 配合物的合成和反应性。我们证明，在温和条件下，可以通过 S-(三氟甲基)二苯并噻吩翁三氟甲磺酸酯以及二芳基碘鎓和芳基重氮盐试剂氧化 Ni(II)前体来获得可分离的 Ni(IV)配合物。Ni(IV)中间体经历高产率的芳基-CF3 键形成还原消除。这些研究支持 Ni(IV)中间体在涉及二芳基碘鎓和芳基重氮盐亲电试剂的镍催化偶联反应中的潜在可行性。
