Nucleophilic Aromatic Substitution in Hydrodefluorination Exemplified by Hydridoiridium(III) Complexes with Fluorinated Phenylsulfonyl-1,2-diphenylethylenediamine Ligands
Nucleophilic Aromatic Substitution in Hydrodefluorination Exemplified by Hydridoiridium(III) Complexes with Fluorinated Phenylsulfonyl-1,2-diphenylethylenediamine Ligands
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DOI：
10.1021/acs.organomet.8b00242
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发表时间：
2018-06
期刊：
影响因子：
2.8
通讯作者：
A. Matsunami;Y. Kayaki;S. Kuwata;T. Ikariya
中科院分区：
文献类型：
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作者：
A. Matsunami;Y. Kayaki;S. Kuwata;T. Ikariya
关于氟代芳烃催化还原的机理，研究了用作氢转移催化剂的一系列铱氢化物的分子内脱氟转化。带有氟化苯磺酰基 - 1,2 - 二苯乙二胺配体的氢化铱(III)配合物通过在邻位选择性地断裂C - F键自发地转化为铱环。核磁共振波谱研究以及中间模型化合物的合成验证了逐步的反应途径，包括氢化配体对邻位氟原子的分子内取代，即加氢脱氟（HDF），以及随后在瞬时形成的C - H键处氟化物辅助的环金属化。具有2,3,4,5,6 - 五氟苯磺酰基（Fs）取代基的氢化铱配合物比其具有2,3,4,5 - 四氟苯磺酰基（FsH）基团的类似物更容易发生HDF。FsH衍生物清楚地表明，C - F键断裂优先于C - H活化发生。这些实验结果……
In connection with the mechanism of the catalytic reduction of fluoroarenes, the intramolecular defluorinative transformation of a family of iridium hydrides utilized as a hydrogen transfer catalyst is studied. Hydridoiridium(III) complexes bearing fluorinated phenylsulfonyl-1,2-diphenylethylenediamine ligands are spontaneously converted into iridacycles via selective C–F bond cleavage at the ortho position. NMR spectroscopic studies and synthesis of intermediate model compounds verify the stepwise pathway involving intramolecular substitution of the ortho-fluorine atom by the hydrido ligand, i.e., hydrodefluorination (HDF), and the following fluoride-assisted cyclometalation at the transiently formed C–H bond. A hydridoiridium complex with a 2,3,4,5,6-pentafluorophenylsulfonyl (Fs) substituent is more susceptible to HDF than its analog with a 2,3,4,5-tetrafluorophenylsulfonyl (FsH) group. The FsH-derivative clearly shows that C–F bond cleavage occurs in preference to C–H activation. These experimental re...