Oxidation of a cyclometalated Pd(II) dimer with "CF3+": formation and reactivity of a catalytically competent monomeric Pd(IV) aquo complex.
Oxidation of a cyclometalated Pd(II) dimer with "CF3+": formation and reactivity of a catalytically competent monomeric Pd(IV) aquo complex.
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DOI：
10.1021/ja107780w
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发表时间：
2010-10-20
影响因子：
15
通讯作者：
Sanford MS
中科院分区：
文献类型：
--
作者：
Ye Y;Ball ND;Kampf JW;Sanford MS
研究了[(bzq)Pd(OAc)]2 （bzq =苯并[h]喹啉）与“CF3+”试剂反应生成单体PdIV水合物（bzq）Pd(CF3)(OAc)2（OH2）。在60℃下加热该PdIV加合物12小时，导致高度化学选择性的芳基- cf3成键还原消除。Brønsted和Lewis酸性添加剂的加入均显著提高了这一转变的速率和产率。对（bzq）Pd(CF3)(OAc)2（OH2）形成C-CF3键的机理进行了研究，提出了预平衡乙酸解离后C-CF3偶联的主要途径。最后，该单体PdIV配合物被证明是与“CF3+”试剂进行C-H三氟甲基化的动力学胜任中间体。总的来说，这些研究为催化C-H三氟甲基化反应中Pd中间体的形态、核性和反应性提供了有价值的见解。
The reaction of [(bzq)Pd(OAc)]2 (bzq = benzo[h]quinoline) with “CF3+” reagents to afford the monomeric PdIV aquo complex (bzq)Pd(CF3)(OAc)2(OH2) is demonstrated. Heating this PdIV adduct at 60 °C for 12 h leads to highly chemoselective Aryl–CF3 bond-forming reductive elimination. The rate and yield of this transformation are both significantly enhanced by the addition of Brønsted and Lewis acidic additives. The mechanism of C–CF3 bond-formation from (bzq)Pd(CF3)(OAc)2(OH2) has been studied, and the major pathway is proposed to involve pre-equilibrium acetate dissociation followed by C–CF3 coupling. Finally, this monomeric PdIV complex is shown to be a kinetically competent intermediate for C–H trifluoromethylation with “CF3+” reagents. Collectively, these studies provide valuable insights about the speciation, nuclearity, and reactivity of Pd intermediates in catalytic C–H trifluoromethylation reactions.
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影响因子：
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