合成了含有(五甲基环戊二烯基)铱(III)单元的一组iridacycles [{C,N} Cp * Ir III -Cl]({C,N} =苯并[ h ]喹啉,二苯并[ f,h ]喹啉)并衍生为与BArF型阴离子缔合的阳离子[{C,N} Cp * Ir-NCMe] +。后者的盐因其在H 2中对HSiEt 3的潜在催化性能而进行了基准测试-释放测试反应。表现最佳的BArF型盐显示出能够以低的催化负载量(大约)促进反应的能力。乙腈,丙腈和一系列芳腈底物的自动串联氢化硅烷化为0.5–1 mol%。机理研究证实,Si-H键的亲电和杂合活化可初步形成硅烷-铱环加合物。通过X射线衍射分析解析了这种加合物的新实例的分子结构。理论上的考虑支持了施主-受主[{C,N} Cp * Ir III -H]→[SiEt 3 ] +({C,N} =苯并[ h ]喹啉基)的配方,其中阳离子甲硅烷基部分充当Z配体结合Ir和
heterolytic activation of the Si–H bond. The molecular structure of a new example of such an adduct was resolved by X-ray diffraction analysis. Theoretical considerations support a donor–acceptor [C,N}Cp*IrIII-H]→[SiEt3]+ (C,N} = benzo[h]quinolinyl) formulation where the cationic silyl moiety acting as a Z ligand binds both Ir and H centers. Under the conditions of the catalysis, the latter adduct is assumed
合成了含有(五甲基环戊二烯基)铱(III)单元的一组iridacycles [C,N} Cp * Ir III -Cl](C,N} =苯并[ h ]喹啉,二苯并[ f,h ]喹啉)并衍生为与BArF型阴离子缔合的阳离子[C,N} Cp * Ir-NCMe] +。后者的盐因其在H 2中对HSiEt 3的潜在催化性能而进行了基准测试-释放测试反应。表现最佳的BArF型盐显示出能够以低的催化负载量(大约)促进反应的能力。乙腈,丙腈和一系列芳腈底物的自动串联氢化硅烷化为0.5–1 mol%。机理研究证实,Si-H键的亲电和杂合活化可初步形成硅烷-铱环加合物。通过X射线衍射分析解析了这种加合物的新实例的分子结构。理论上的考虑支持了施主-受主[C,N} Cp * Ir III -H]→[SiEt 3 ] +(C,N} =苯并[ h ]喹啉基)的配方,其中阳离子甲硅烷基部分充当Z配体结合Ir和
Catalytic Ketone Hydrodeoxygenation Mediated by Highly Electrophilic Phosphonium Cations
作者:Meera Mehta、Michael H. Holthausen、Ian Mallov、Manuel Pérez、Zheng-Wang Qu、Stefan Grimme、Douglas W. Stephan
DOI:10.1002/anie.201502579
日期:2015.7.6
Ketones are efficiently deoxygenated in the presence of silane using highly electrophilic phosphonium cation (EPC) salts as catalysts, thus affording the corresponding alkane and siloxane. The influence of distinct substitution patterns on the catalytic effectiveness of several EPCs was evaluated. The deoxygenation mechanism was probed by DFT methods.
Hydrosilylation of Ketones, Imines and Nitriles Catalysed by Electrophilic Phosphonium Cations: Functional Group Selectivity and Mechanistic Considerations
作者:Manuel Pérez、Zheng-Wang Qu、Christopher B. Caputo、Vitali Podgorny、Lindsay J. Hounjet、Andreas Hansen、Roman Dobrovetsky、Stefan Grimme、Douglas W. Stephan
DOI:10.1002/chem.201406356
日期:2015.4.20
efficient hydrosilylation of ketones, imines and nitriles at room temperature. In the presence of this catalyst, adding one equivalent of hydrosilane to a nitrile yields a silylimine product, whereas adding a second equivalent produces the corresponding disilylamine. [(C6F5)3PCl][B(C6F5)4] and [(C6F5)3PBr][B(C6F5)4] are also synthesised and tested as catalysts. Competition experiments demonstrate that the
亲电子phospho盐,[(C 6 F 5)3 PF] [B(C 6 F 5)4 ],在室温下催化酮,亚胺和腈的有效氢化硅烷化。在这种催化剂的存在下,向腈中加入一当量的氢硅烷会产生甲硅烷基苯丙胺产物,而添加第二当量的甲硅烷会产生相应的二甲硅烷基胺。[(C 6 F 5)3 PCl] [B(C 6 F 5)4 ]和[(C 6 F 5)3 PBr] [B(C 6 F 5)4也被合成并作为催化剂测试。竞争实验表明,该反应对以下官能团表现出选择性,其优先顺序为:酮>腈>亚胺>烯烃。计算研究表明,该反应机理涉及通过与with中心的相互作用而使SiH键初始活化。然后,活化的络合物协同作用于不饱和底物上。
Axially Chiral, Electrophilic Fluorophosphonium Cations: Synthesis, Lewis Acidity, and Reactivity in the Hydrosilylation of Ketones
作者:Lars Süsse、James H. W. LaFortune、Douglas W. Stephan、Martin Oestreich
DOI:10.1021/acs.organomet.8b00912
日期:2019.2.11
FIA and GEI values attest that these new fluorophosphonium cations have a higher Lewis acidity compared to the ubiquitous B(C6F5)3. Furthermore, application of these highly electrophilic compounds in the catalytic hydrosilylation of ketones and an investigation of the mechanism lead to a refined picture of the role of highly electrophilic fluorophosphonium cations.
制备了基于具有双萘基骨架的二氢膦类的轴向手性[(C 6 F 5)3 PF] [B(C 6 F 5)4 ]类似物,并通过X射线衍射分析对其结构进行了表征。FIA和GEI值的计算计算证明,与普遍存在的B(C 6 F 5)3相比,这些新的氟phosph阳离子具有更高的路易斯酸度。此外,将这些高度亲电的化合物应用于酮的催化硅氢加成反应以及对其机理的研究,可以使人们进一步了解高度亲电的氟phosph阳离子的作用。