Use of Acylhydrazine- and Acylhydrazone-Type Ligands to Promote CuI-Catalyzed C-N Cross-Coupling Reactions of Aryl Bromides with N-Heterocycles
作者:Liuyi Li、Lei Zhu、Dagui Chen、Xuelei Hu、Ruihu Wang
DOI:10.1002/ejoc.201100112
日期:2011.5
A series of ten acylhydrazine- and acylhydrazone-typeligands were designed and synthesized. Their electronic and steric properties were easily modified and tuned by varying the substituents in the vicinity of the acylhydrazine and acylhydrazone units. The effect of ligands on the catalytic activity of Ullmann reactions was assessed by using a combination of these ligands with CuI. The catalytic system
设计并合成了一系列十个酰基肼和酰基腙型配体。通过改变酰基肼和酰基腙单元附近的取代基,它们的电子和空间性质很容易被修改和调整。通过使用这些配体与 CuI 的组合来评估配体对 Ullmann 反应催化活性的影响。该催化体系对于唑类与芳基和杂芳基溴化物的 C-N 偶联反应非常有效。
Magnetic nanoparticle-supported proline as a recyclable and recoverable ligand for the CuI catalyzed arylation of nitrogen nucleophiles
作者:Gagan Chouhan、Dashan Wang、Howard Alper
DOI:10.1039/b711298j
日期:——
Magnetic nanoparticle-supported proline ligand was prepared and used for the CuI catalyzed Ullmann-type coupling reactions of aryl/heteroaryl bromides with various nitrogen heterocycles to form the corresponding N-aryl products in good to excellent yields; furthermore, this magnetic nanoparticle-supported proline ligand could be readily separated using an external magnet and reused without significant loss of activity.
Domino <i>N</i>-/<i>C</i>- or <i>N</i>-/<i>N</i>-/<i>C</i>-arylation of imidazoles to yield polyaryl imidazolium salts <i>via</i> atom-economical use of diaryliodonium salts
作者:Shiqing Li、Hongxu Lv、Yu Yu、Xiuqing Ye、Baisong Li、Songming Yang、Yanru Mo、Xiangfei Kong
DOI:10.1039/c9cc05237b
日期:——
Herein, we disclose a Cu-mediated domino di-/triarylation reaction of imidazoles to efficiently access polyaryl imidazolium salts in a single step by using two aryls as well as an anion of a diaryliodonium salt. The diarylation shows high atom economy and excellent selectivity with unsymmetrical iodonium salts.
Rh(I)/(III)‐N‐Heterocyclic Carbene Complexes: Effect of Steric Confinement Upon Immobilization on Regio‐ and Stereoselectivity in the Hydrosilylation of Alkynes
作者:Pradeep K. R. Panyam、Boshra Atwi、Felix Ziegler、Wolfgang Frey、Michal Nowakowski、Matthias Bauer、Michael R. Buchmeiser
DOI:10.1002/chem.202103099
日期:2021.12.6
Novel Rh(III) pentamethylcyclopentadienyl and Rh(I) complexes containing chelating N-heterocycliccarbenes have been prepared and used in the hydrosilylation of 1-alkynes. Selected catalysts were immobilized within the mesopores of SBA-15. The confinement effects either provided by the ligands or the mesoporous support have been studied and allow for hydrosilylation with β(Z)-selectivity of up to 100 %
A magnetically recoverable catalyst consisting of coppernanoparticles (CuNPs) on nanosized silica-coated maghemite is presented. The catalyst has been prepared under mild conditions by mixing the magnetic support with a freshly prepared suspension of CuNPs obtained by fast reduction of anhydrous CuCl2 with lithium sand and a catalytic amount of DTBB (4,4′-di-tert-butylbiphenyl) as electron carrier