Catalytic Electrophilic C−H Borylation Using NHC⋅Boranes and Iodine Forms C2-, not C3-, Borylated Indoles
作者:John S. McGough、Jessica Cid、Michael J. Ingleson
DOI:10.1002/chem.201702060
日期:2017.6.16
that this is due to C3 to C2 boron migration facilitated by the absence of exogenous Brønsted bases. Thus this C−H borylation methodology proceeds under sufficiently Brønsted acidic conditions to enable the thermodynamic C2‐borylated indole isomer to be formed instead of the C3 borylated‐isomer. This demonstrates that electrophilic C−H borylation can be used to access a wider range of borylated regioisomers
N-杂环卡宾硼烷活化(NHC⋅BH 3)由I 2使杂芳烃的形成与H的无金属催化C-H硼化2作为副产物的方法,它使用仅长凳稳定前体。使用NHC⋅BH吲哚的硼化3 / I 2与其他催化亲电CH硼化方法相比,仅能生产C2硼化的吲哚。机理研究表明,这是由于缺乏外源布朗斯台德碱促进了C3向C2硼的迁移。因此,这种CH硼化方法在足够的布朗斯台德酸性条件下进行,以形成热力学C2硼化的吲哚异构体,而不是C3硼化的异构体。这表明亲电CH硼化可以用于比迄今为止报道的更广泛的硼化区域异构体。
Base-Stabilized Boryl and Cationic Haloborylene Complexes of Iron
作者:Philipp Bissinger、Holger Braunschweig、Alexander Damme、Rian D. Dewhurst、Katharina Kraft、Thomas Kramer、Krzysztof Radacki
DOI:10.1002/chem.201302263
日期:2013.9.27
base‐stabilized boryl and borylene complexes is reported. An N‐heterocyclic carbene (NHC)‐stabilized iron–dihydroboryl complex was prepared by two different routes including methane liberation and salt elimination. A range of base‐stabilized iron–dichloroboryl complexes was prepared by addition of Lewis bases to borylcomplexes. Base‐stabilized, cationic monochloroborylene complexes were synthesized
N-Heterocyclic Carbene Boranes as Reactive Oxygen Species-Responsive Materials: Application to the Two-Photon Imaging of Hypochlorous Acid in Living Cells and Tissues
N‐Heterocyclic carbene (NHC) boranes undergo oxidative hydrolysis to give imidazolium salts with excellent kinetic selectivity for HOCl over other reactive oxygen species (ROS), including peroxides and peroxynitrite. Selectivity for HOCl results from the electrophilic oxidation mechanism of NHC boranes, which stands in contrast to the nucleophilic oxidation mechanism of arylboronic acids with ROS.