B(
<scp>
C
<sub>6</sub>
F
<sub>5</sub>
</scp>
)
<scp>
<sub>3</sub>
‐Catalyzed
</scp>
Hydroboration of Alkenes with
<scp>
<i>N</i>
‐Heterocyclic
</scp>
Carbene Boranes
<i>via</i>
B—H Bond Activation
作者:Qiaotian Wang、Wei Meng、Xiangqing Feng、Haifeng Du
DOI:10.1002/cjoc.202000489
日期:2021.4
Significantly, excellent regioselectivities were obtained in some cases. Mechanisticstudies indicate that the B—H bond cleavage is likely involved in the rate‐determining step. In addition, an electrophilic addition of NHC‐borenium cation to alkenes and the subsequent formation of carbocation are also postulated. The current work provides a promising method for the activation of stable borane adducts
在这项工作中,开发了一种新的活化N-杂环卡宾硼烷(NHC-硼烷)的方式,该方式是通过以沮丧的Lewis对方式通过路易斯酸B(C 6 F 5)3氢化物提取生成高反应性的两性离子物质。B(C 6 F 5)3的合适底物包括苯乙烯,β-甲基苯乙烯,苯乙烯和烷基烯烃等多种烯烃。催化硼氢化以高至高收率提供所需的产品。显着地,在某些情况下获得了优异的区域选择性。机理研究表明,在确定速率的步骤中可能涉及到B键的断裂。此外,还假定将NHC-硼阳离子亲电加成到烯烃中,并随后形成碳正离子。目前的工作为稳定硼烷加合物的活化提供了一种有前途的方法,这可能在将来引起一些有趣的转变。
Iron‐Catalyzed Radical Asymmetric Aminoazidation and Diazidation of Styrenes
作者:Daqi Lv、Qiao Sun、Huan Zhou、Liang Ge、Yanjie Qu、Taian Li、Xiaoxu Ma、Yajun Li、Hongli Bao
DOI:10.1002/anie.202017175
日期:2021.5.25
Asymmetric aminoazidation and diazidation of alkenes are straightforward strategies to build value‐added chiral nitrogen‐containing compounds from feedstock chemicals. They provide direct access to chiral organoazides and complement enantioselective diamination. Despite the advances in non‐asymmetric reactions, asymmetric aminoazidation or diazidation based on acyclic systems has not been previously
Ruthenium/dendrimer complex immobilized on silica‐functionalized magnetite nanoparticles catalyzed oxidation of stilbenes to benzil derivatives at room temperature
A new ruthenium/dendrimer complex stabilized on the surface of silica‐functionalized nano‐magnetite was fabricated and well characterized. The nano‐catalyst showed good activity in the synthesis of benzil derivatives via the oxidation of stilbenes with high turnover frequency (TOF) at roomtemperature. Moreover, the catalyst could also be reused up to fifteen times without any loss of its activity
The substituent effect on the acetolysis of 2,2-bis(substituted phenyl)ethyl p-toluenesulfonates at 90.10 °C can be described accurately in terms of the Yukawa–Tsuno (LArSR) relationship, giving a ρ value of −4.44 and an r value of 0.53. The substituent effect correlation of this system carrying two aryls is quite comparable to that of the 2-methyl-2-phenylpropyl system carrying a single aryl group, suggesting the close similarity in the structure of the transition states between the systems. The results can be reasonably accounted for on the basis of the accepted mechanism of this reaction, involving a rate-determining aryl-assisted transition state where only one aryl group of the two β-aryl groups participates.