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
[η<sup>5</sup>-Cp*B-Mes]<sup>+</sup>: A Masked Potent Boron Lewis Acid
The chemistry of the boron cation has been revitalized in the past decade due to its newfound application in stoichiometric and catalytic organic reactions. To extend the frontier of boron cation catalysis, we came to discover that a mesityl-substituted η5-Cp*-coordinated boron cation could serve as a powerful Lewisacid for organic catalytic transformations. The boron cation [Cp*B-Mes][B(C6F5)4] ([1][B(C6F5)4])
由于硼阳离子在化学计量和催化有机反应中的新发现,在过去的十年中,硼阳离子的化学得到了振兴。为了延长硼阳离子催化的前沿,我们来到发现一个均三甲苯基取代的η 5 -Cp *配位的硼阳离子可以作为一种强大的路易斯酸为有机催化转化。稳定在硼状电子结构中的硼阳离子[Cp * B-Mes] [B(C 6 F 5)4 ]([ 1 ] [B(C 6 F 5)4 ])易于与Et 3 PO结合,显示的受主编号超过B(C 6 F 5)3在Gutmann-Beckett酸度等级上。给电子Cp *产生的空间和电子稳定性使高路易斯酸性硼阳离子成为在环境温度下易于进行芳基酮加氢脱氧的催化剂。[ 1 ] +的出色的催化性能表明,在硼中引入配位柔性取代基对于为硼阳离子催化剂带来催化活性和稳定性至关重要。
Carbonyl and olefin hydrosilylation mediated by an air-stable phosphorus(<scp>iii</scp>) dication under mild conditions
作者:Ryan J. Andrews、Saurabh S. Chitnis、Douglas W. Stephan
DOI:10.1039/c9cc02460c
日期:——
The readily-accessible, air-stable Lewis acid [(terpy)PPh][B(C6F5)4]21 is shown to mediate the hydrosilylation of aldehydes, ketones, and olefins. The utility and mechanism of these hydrosilylations are considered.
已显示出易于获得的,空气稳定的路易斯酸[(terpy)PPh] [B(C 6 F 5)4 ] 2 1可介导醛,酮和烯烃的氢化硅烷化。考虑了这些氢甲硅烷基化的效用和机理。
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.
α-Substitution effect of fluorine atoms in the cobalt-catalyzed hydrosilylation of fluorine-containing aromatic ketones
作者:Tatsuya Kumon、Siti Asiah Binti Mohd Sari、Shigeyuki Yamada、Tsutomu Konno
DOI:10.1016/j.jfluchem.2017.12.003
日期:2018.2
Hydrosilylation of fluorine-containing aromaticketones with triethylsilane in the presence of a catalytic amount of a low-cost and an environmentally benign cobalt catalyst proceeded very smoothly to give the corresponding adducts. Interestingly, this hydrosilylation reaction was not applicable to non-fluorinated ketones. As revealed by density functional theory analysis, a fluorine substituent at