Nickel(II/IV) Manifold Enables Room-Temperature C(sp 3 )–H Functionalization
Nickel(II/IV) Manifold Enables Room-Temperature C(sp 3 )–H Functionalization
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镍 (II/IV) 歧管可实现室温 C(sp 3 )–H 功能化
DOI：
10.1021/jacs.9b11999
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发表时间：
2019
影响因子：
15
通讯作者：
Sanford, Melanie S.
中科院分区：
文献类型：
--
作者：
Roberts, Courtney C.;Chong, Eugene;Kampf, Jeff W.;Canty, Allan J.;Ariafard, Alireza;Sanford, Melanie S.
这篇文章证明了在高价Ni中心处的温和氧化诱导的C（sp3）-H活化。与大多数C（sp3）-H在NiII的活化反应相反，该转化在室温下进行并产生可分离的NiIVσ-烷基络合物。密度泛函理论的研究表明，这种C-H活化过程涉及三氟甲磺酸酯辅助C-H裂解在NiIV或NiIII中间体的两个合理的机制。前一种途径比后一种途径稍受青睐（相差0.33千卡/摩尔）。C-H裂解的NiIVσ-烷基产物与各种亲核试剂反应形成C（sp3）-X键（X =卤素、氧、氮、硫或碳）。这些化学计量转化可以使用N-氟-2，4，6-三甲基吡啶鎓三氟甲磺酸盐作为末端氧化剂结合氯化物作为亲核试剂进行偶联，以实现原理证明NiII/IV催化的C（sp3）-H官能化反应。
This Article demonstrates a mild oxidatively induced C(sp3)–H activation at a high-valent Ni center. In contrast with most C(sp3)–H activation reactions at NiII, the transformation proceeds at room temperature and generates an isolable NiIVσ-alkyl complex. Density functional theory studies show two plausible mechanisms for this C–H activation process involving triflate-assisted C–H cleavage at either a NiIVor a NiIIIintermediate. The former pathway is modestly favored over the latter (by ∼3 kcal/mol). The NiIVσ-alkyl product of C–H cleavage reacts with a variety of nucleophiles to form C(sp3)–X bonds (X = halide, oxygen, nitrogen, sulfur, or carbon). These stoichiometric transformations can be coupled usingN-fluoro-2,4,6-trimethylpyridinium triflate as a terminal oxidant in conjunction with chloride as a nucleophile to achieve a proof-of-principle NiII/IV-catalyzed C(sp3)–H functionalization reaction.