A New Mode of Operation of Pd-NHC Systems Studied in a Catalytic Mizoroki–Heck Reaction
摘要:
Metal complexes bearing N-heterocyclic carbene (NHC) ligands are typically considered the system of choice for homogeneous catalysis with well-defined molecular active species due to their stable metal ligand framework. A detailed study involving 19 different Pd-NHC complexes with imidazolium, benzimidazolium, and triazolium ligands has been carried out in the present work and revealed a new mode of operation of metal-NHC systems. The catalytic activity of the studied Pd-NHC systems is predominantly determined by the cleavage of the metal NHC bond, while the catalyst performance is strongly affected by the stabilization of in situ formed metal clusters. In the present study, the formation of Pd nanopartides was observed from a broad range of metal complexes with NHC ligands under standard Mizoroki-Heck reaction conditions. A mechanistic analysis revealed two different pathways to connect Pd-NHC complexes to "cocktail"-type catalysis: (i) reductive elimination from a Pd(II) intermediate and the release of NHC-containing byproducts and (ii) dissociation of NHC ligands from Pd intermediates. Metal-NHC systems are ubiquitously applied in modern organic synthesis and catalysis, while the new mode of operation revealed in the present study guides catalyst design and opens a variety of novel opportunities. As shown by experimental studies and theoretical calculations, metal dusters and nanopartides can be readily formed from M-NHC complexes after formation of new M-C or M-H bonds followed by C-NHC or H-NHC coupling. Thus, a combination of a classical molecular mode of operation and a novel cocktail-type mode of operation, described in the present study, may be anticipated as an intrinsic feature of M-NHC catalytic systems.
[EN] STAT DEGRADERS AND USES THEREOF<br/>[FR] AGENTS DE DÉGRADATION DE STAT ET LEURS UTILISATIONS
申请人:KYMERA THERAPEUTICS INC
公开号:WO2021188696A1
公开(公告)日:2021-09-23
The present invention provides compounds, compositions thereof, and methods of using the same.
本发明提供了化合物、其组合物以及使用相同的方法。
Synthesis and characterization of N-heterocyclic carbene-palladium(<scp>ii</scp>) chlorides-1-methylindazole and -1-methylpyrazole complexes and their catalytic activity toward C–N coupling of aryl chlorides
作者:Xiao-Yun Zhao、Quan Zhou、Jian-Mei Lu
DOI:10.1039/c6ra02556k
日期:——
series of N-heterocycliccarbene-palladium(II) chlorides-1-methylindazole and -1-methylpyrazole complexes was successfully synthesized and fully characterized by X-ray single crystal diffraction. In addition, initial investigations of their catalytic activity showed that they were efficientcatalysts in the C–N coupling of primary and secondary amines with aryl chlorides at low catalyst loadings.
COMPOUNDS HAVING MUSCARINIC RECEPTOR ANTAGONIST AND BETA2 ADRENERGIC RECEPTOR AGONIST ACTIVITY
申请人:CHIESI FARMACEUTICI S.p.A
公开号:US20140161736A1
公开(公告)日:2014-06-12
Compounds of formula (I) described herein act both as muscarinic receptor antagonists and beta2 adrenergic receptor agonists and are useful for the prevention and/or treatment of broncho-obstructive or inflammatory diseases.
Synthesis of N-heterocyclic carbene-Pd(II)-5-phenyloxazole complexes and initial studies of their catalytic activity toward the Buchwald-Hartwig amination of aryl chlorides
作者:Zhi-Mao Zhang、Yu-Ting Xu、Li-Xiong Shao
DOI:10.1016/j.jorganchem.2021.121683
日期:2021.5
N-heterocyclic carbene (NHC)-Pd(II) complexes using 5-phenyloxazole as the ancillary ligand have been obtained in moderate to good yields by a one-pot reaction of the corresponding imidazolium salts, palladium chloride and 5-phenyloxazole under mild conditions. Initial studies showed that one of the complexes is an efficient catalyst for the Buchwald-Hartwig amination of arylchlorides with various secondary
Synthesis of N-heterocyclic carbene–PdCl<sub>2</sub>–(iso)quinoline complexes and their application in arylamination at low catalyst loadings
作者:Feng Liu、Yi-Ran Zhu、Lu-Gan Song、Jian-Mei Lu
DOI:10.1039/c6ob00013d
日期:——
N-Heterocyclic carbene–PdCl2–(iso)quinoline complexes were synthesized and they showed efficient catalytic activity in the C–N coupling of aryl chlorides.