Elite cliques: Palladiumclusters with three and four atoms were found to be the catalyticallyactivespecies for ligand‐free palladium‐catalyzed CC bond‐forming reactions (see picture). These palladiumclusterspecies could be stabilized in water and stored for long periods of time for use on demand with no loss of activity. High yields of products and turnover frequencies (TOFs) of up to 105 h−1
精英集团:发现具有三个和四个原子的钯簇是无配体钯催化的CC键形成反应的催化活性物种(见图)。这些钯簇物种可以在水中稳定下来,并可以长期保存,以供按需使用,而不会损失活性。观察到高产量的产品和高达10 5 h -1的周转频率(TOF)。
Ligand Exchange as the First Irreversible Step in the Nickel-Catalyzed Cross-Coupling Reaction of Grignard Reagents
Mechanistic studies of the Ni-catalyzed cross-coupling reaction of Grignardreagents through analysis of kinetic isotope effects and theoretical calculations indicated that the product-to-substrate ligand exchange process is the first irreversible step and affects the turnover efficiency and selectivity of the reaction. On the other hand, the oxidative addition step is the first irreversible step in
通过动力学同位素效应分析和理论计算对镍催化格氏试剂交叉偶联反应的机理研究表明,产物到底物配体交换过程是第一个不可逆步骤,影响反应的周转效率和选择性。另一方面,氧化加成步骤是 Pd 催化中的第一个不可逆步骤。这一发现对开发高效的 Ni 催化具有有用的意义,并且还说明了催化剂周转步骤的重要性,迄今为止,该步骤比后续的催化步骤受到的关注较少。
Cyclomagnesation of cycloalkynes with the use of RMgR’ catalyzed by zirconium complexes
作者:V. A. D’yakonov、A. A. Makarov、U. M. Dzhemilev
DOI:10.1134/s1070428009110037
日期:2009.11
The intermolecular cyclomagnesation of cycloalkynes and joint cyclomagnesation of cycloalkynes and disubstituted acetylenes was carried out by treating with RMgR' (R, R' = Et, Bu, H1g) in the presence of Cp2ZrCl2 as a catalyst. As a result new unsaturated bi-and tricyclic organomagnesium compounds were obtained in high yields.