Tandem allylic oxidation–condensation/esterification catalyzed by silica gel: an expeditious approach towards antimalarial diaryldienones and enones from natural methoxylated phenylpropenes
Ionic Pd/NHC Catalytic System Enables Recoverable Homogeneous Catalysis: Mechanistic Study and Application in the Mizoroki–Heck Reaction
作者:Dmitry B. Eremin、Ekaterina A. Denisova、Alexander Yu. Kostyukovich、Jonathan Martens、Giel Berden、Jos Oomens、Victor N. Khrustalev、Victor M. Chernyshev、Valentine P. Ananikov
DOI:10.1002/chem.201903221
日期:2019.12.20
concentrations. The present study reveals a dynamic stabilization mechanism with labile metal-NHC binding and [PdX3 ]- [NHC-R]+ ion pair formation. Access to reactive anionic palladium intermediates formed by dissociation of the NHC ligands and plausible stabilization of the molecular catalyst in solution by interaction with the [NHC-R]+ azolium ion is of particular importance for an efficient and recyclable catalyst
S,O-Functionalized Metal–Organic Frameworks as Heterogeneous Single-Site Catalysts for the Oxidative Alkenylation of Arenes via C–H activation
作者:Niels Van Velthoven、Mickaël Henrion、Jesse Dallenes、Andraž Krajnc、Aram L. Bugaev、Pei Liu、Sara Bals、Alexander V. Soldatov、Gregor Mali、Dirk E. De Vos
DOI:10.1021/acscatal.0c00801
日期:2020.5.1
organometallic complexes with the efficient recovery of solid catalysts. Based on recent progress on homogeneous thioether ligands for Pd-catalyzed C–H activation reactions, we here develop a scalable metal–organic framework-based heterogeneous single-site catalyst containing S,O-moieties that increase the catalyticactivity of Pd(II) for the oxidative alkenylation of arenes. The structure of the Pd@MOF-808-L1
异质单中心催化剂可以将有机金属配合物的精确活性中心设计与固体催化剂的有效回收结合起来。基于用于Pd催化的C–H活化反应的均相硫醚配体的最新进展,我们在此开发可扩展的基于金属-有机骨架的含S,O部分的异质单中心催化剂,可提高Pd(II)的催化活性。用于芳烃的氧化烯基化。所述的结构的Pd @ MOF-808-L1催化剂通过固态核磁共振谱法进行详细表征,N 2物理吸附和高角度环形暗场扫描透射电子显微镜,以及分离的钯活性位点的结构可以通过X射线吸收光谱法进行鉴定。反应时间1小时后,转换频率(TOF)为8.4 h –1,是标准Pd(OAc)2的TOF的3倍,在活性最高的非均相催化剂中排名Pd @ MOF-808-L1曾经报道过芳烃的非定向氧化烯基化。最后,我们证明了单中心催化剂可促进多种富电子芳烃的氧化烯基化,并且该无均相体系的适用性通过工业相关产品的克级合成得到证明。
Controlling reactivity in the Fujiwara–Moritani reaction: Examining solvent effects and the addition of 1,3-dicarbonyl ligands on the oxidative coupling of electron rich arenes and acrylates
作者:Roderick C. Jones
DOI:10.1016/j.tetlet.2019.151471
日期:2020.2
alkenation of electron rich arenes in the presence of K2S2O8 with an acetic acid/1,4-dioxane solvent combination has been developed. The 1,4-dioxane co-solvent dramatically influences the rate of reaction, giving selectively disubstituted alkenes, while the addition of acetylacetone ligands was shown to increase site selectivity for the alkenation of monofunctionalized arenes. The participation of these
已经开发了在K 2 S 2 O 8存在下,用乙酸/ 1,4-二恶烷溶剂组合的钯催化的富电子芳烃的直接烷化反应。1,4-二恶烷共溶剂显着影响反应速率,产生选择性二取代的烯烃,而乙酰丙酮配体的添加显示出增加了单官能化芳烃链烯化的位点选择性。这些羰基配体的参与已通过ESI-MS研究确认,并确定了催化循环中的一些关键原位中间体。可以在直接氧化偶合中使用多种富电子芳烃和烯烃底物,以中等至良好的产率得到二取代的烯烃。
Non-directed Pd-catalysed electrooxidative olefination of arenes
is a powerful tool for the olefination of arenes by Pd-catalysed C–H activation. However, the need for superstoichiometric amounts of toxic chemical oxidants makes the reaction unattractive from an environmental and atom-economical view. Herein, we report the first non-directed and regioselective olefination of simple arenes via an electrooxidative Fujiwara–Moritani reaction. The versatility of this
Fujiwara-Moritani 反应是通过 Pd 催化的 C-H 活化进行芳烃烯化的有力工具。然而,由于需要超化学计量的有毒化学氧化剂,因此从环境和原子经济角度来看,该反应没有吸引力。在此,我们报告了通过电氧化藤原-森谷反应实现简单芳烃的第一个非定向和区域选择性烯化。这种操作友好的方法的多功能性通过广泛的底物范围得到了证明,其中包括芳烃、杂芳烃和各种烯烃。电分析研究表明 Pd( II )/Pd( IV ) 催化循环通过Pd( III ) 中间体参与。
Palladium(O) and rhodium(I) catalysis of the carbonylation of unactivated bromides