Catalytic Deuteration of C(sp 2 )–H Bonds of Substituted (Hetero)arenes in a Pt(II) CNN-Pincer Complex/2,2,2-Trifluoroethanol- d 1 System: Effect of Substituents on the Reaction Rate and Selectivity
Catalytic Deuteration of C(sp 2 )–H Bonds of Substituted (Hetero)arenes in a Pt(II) CNN-Pincer Complex/2,2,2-Trifluoroethanol- d 1 System: Effect of Substituents on the Reaction Rate and Selectivity
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Pt(II) CNN-Pincer 配合物/2,2,2-三氟乙醇- d 1 体系中取代（杂）芳烃 C(sp 2 )–H 键的催化氘化：取代基对反应速率和
DOI：
10.1021/acs.organomet.0c00652
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发表时间：
2020
期刊：
影响因子：
2.8
通讯作者：
Vedernikov, Andrei N.
中科院分区：
文献类型：
--
作者：
Kramer, Morgan;Watts, David;Vedernikov, Andrei N.
在80 °C下，在磺化CN-钳形配体负载的均相Pt（II）络合物1存在下，对34种（杂）芳烃衍生物进行了涉及其C（sp2）-H键和2，2，2-三氟乙醇-d1（TFE-d1）的催化H/D交换反应的测试。的18个基板，包括一个药物（napolecen），这是稳定的1的存在下，并在H/D交换反应中是活跃的，其特征在于它们的位置特定程度的氘化，并在一些情况下，反应动力学选择性。对于反应性最强的底物，氘化程度接近可交换的H和D原子的预期统计分布：例如，对苯酚，23 h后的H/D交换率为67-69%，45 min后的H/D交换率为88%。对一些底物（N，N-二甲基苯胺、吲哚、硝基苯），H/D交换具有高度位置选择性。X-单取代苯的位置特异性（Meta、帕拉）H/D交换速率常数与Hammett σ X常数之间没有令人满意的相关性。这一观察结果被认为与CH键活化的协同性质有关，CH键在Pt（II）中心氧化加成的速率决定。引入一种新的Hammett σ MX常数标度来表征C（sp2）-H键在过渡金属介导反应中的反应活性.实验测定的取代苯（间位和对位）以及噻吩（α和β位）的H/D交换活化的位置特异性Gibbs能用DFT计算令人满意地匹配。
Thirty four (hetero)arene derivatives have been tested in catalytic H/D exchange reactions involving their C(sp2)–H bonds and 2,2,2-trifluoroethanol-d1(TFE-d1) in the presence of the homogeneous Pt(II) complex1supported by a sulfonated CNN-pincer ligand at 80 °C. The 18 substrates, including one pharmaceutical (naproxen), that are stable in the presence of1and are active in the H/D exchange reaction have been characterized by their position-specific extent of deuteration and, in a number of cases, the reaction kinetic selectivity. For the most reactive substrates the extent of deuteration approaches the expected statistical distribution of the exchangeable H and D atoms: e.g., 67–69% for phenol after 23 h and 88% for indole β-CH bonds after 45 min. For a few substrates (N,N-dimethylaniline, indole, nitrobenzene) the H/D exchange is highly position selective. No satisfactory correlation was found between the position-specific (meta,para) H/D exchange rate constants for X-monosubstituted benzenes and Hammett σXconstants. This observation was proposed to be related to the concerted nature of the CH bond activation, the rate-determining CH bond oxidative addition at a Pt(II) center. A novel scale of Hammett σMXconstants was introduced to characterize the reactivity of C(sp2)–H bonds in transition-metal-mediated reactions. The experimentally determined position-specific Gibbs energies of activation of the H/D exchange in substituted benzenes (metaandparapositions) as well as in thiophene (α and β positions) were matched satisfactorily using DFT calculations.