38015-82-6Relevant academic research and scientific papers
Sterically Encumbered Tetraarylimidazolium Carbene Pd-PEPPSI Complexes: Highly Efficient Direct Arylation of Imidazoles with Aryl Bromides under Aerobic Conditions
He, Xu-Xian,Li, Yinwu,Ma, Bei-Bei,Ke, Zhuofeng,Liu, Feng-Shou
, p. 2655 - 2663 (2016/09/04)
A series of sterically encumbered tetraarylimidazolium carbene Pd-PEPPSI complexes were conveniently prepared and fully characterized. These sterically encumbered Pd-PEPPSI complexes act as active precatalysts for the direct arylation of imidazoles with aryl bromides under aerobic conditions. The catalytic performance of Pd-PEPPSI complexes in cross-coupling processes is investigated. Under the optimal protocols, the cross-coupling reactions regioselectively produced C5-arylation products in moderate to excellent yields, which could tolerate a wide range of functional aryl bromides.
Palladium-Catalyzed Synthesis of α-Diimines from Triarylbismuthines and Isocyanides
Kobiki, Yohsuke,Kawaguchi, Shin-Ichi,Ogawa, Akiya
supporting information, p. 3490 - 3493 (2015/07/28)
In this study, we report a highly selective coupling reaction between triarylbismuthines and isocyanides using palladium diacetate as the catalyst, affording α-diimines, with the formation of three C-C bonds. Among several aryl sources (Ar-YLn: Y = B, Sn, Pb, Sb, Bi, I), only triarylbismuthines successfully undergo coupling with isocyanides to selectively afford α-diimines. The coupling reaction exhibits the advantages of high atom economy and convenient operation, with no need for any additive.
Substituent effects of the backbone in α-diimine palladium catalysts on homo- and copolymerization of ethylene with methyl acrylate
Guo, Lihua,Gao, Haiyang,Guan, Qirui,Hu, Haibin,Deng, Juean,Liu, Jun,Liu, Fengshou,Wu, Qing
, p. 6054 - 6062 (2012/10/30)
On the basis of different approaches for modifying α-diimine palladium catalysts, a series of methyl chloride palladium complexes with various α-diimine ligand backbones were synthesized and characterized. The corresponding cationic palladium complex chelating esters were further obtained by treatment of methyl chloride palladium complexes with methyl acrylate (MA). It was observed that decomposition of a cationic palladium complex chelating ester can occur to produce a new cationic palladium complex chelating two ligands and two counteranions, which provides a new pathway for deactivation of palladium catalysts and formation of palladium black by a fragmentation pattern with ester loss. These α-diimine palladium catalysts were employed in the homopolymerization of ethylene and copolymerization of ethylene and MA to evaluate substituent effects of the ligand backbone. A bulky camphyl α-diimine palladium catalyst was found to show better thermal stability and afford high-molecular-weight copolymer with higher incorporation of polar monomer. Longstanding living polymerization of ethylene was also achieved within 12 h using a bulky camphyl α-diimine palladium catalyst.
