Phosphine-free palladium-catalysed direct 5-arylation of imidazole derivatives at low catalyst loading
作者:Julien Roger、Henri Doucet
DOI:10.1016/j.tet.2009.09.084
日期:2009.11
The regioselective 5-arylation of imidazole derivatives with aryl bromides using a low loading of a phosphine-free palladium catalyst gives a simple and economic access to the corresponding 5-arylimidazoles. The choice of the base and of the solvent was found to be crucial to form these products in high yields. Using KOAc as the base, DMAc as the solvent and only 0.5–0.01 mol % Pd(OAc)2 as the catalyst
Developing Bis(imino)acenaphthene-Supported <i>N</i>-Heterocyclic Carbene Palladium Precatalysts for Direct Arylation of Azoles
作者:Li-Qun Hu、Rong-Li Deng、Yan-Fen Li、Cui-Jin Zeng、Dong-Sheng Shen、Feng-Shou Liu
DOI:10.1021/acs.organomet.7b00784
日期:2018.1.22
On the basis of the strategy of developing highly efficient protocol for Pd-catalyzed cross-coupling reactions, a series of bulky bis(imino)acenaphthene (BIAN)-supported Pd-PEPPSI complexes were synthesized, characterized, and applied in direct arylation of azoles. The effect of backbone and N-moieties on NHCs was evaluated, and the reaction conditions were optimized. It was found that the bulky Pd-PEPPSI complexes could be successfully employed in cross-coupling of (hetero)aryl bromides with azoles at a low palladium loading of 0.5-0.05 mol % under aerobic conditions, demonstrating the ease of manipulation without glovebox and handling of solvents.
Bulky α-diimine palladium complexes: highly efficient for direct C–H bond arylation of heteroarenes under aerobic conditions
作者:Jia-Sheng Ouyang、Yan-Fang Li、Dong-Sheng Shen、Zhuofeng Ke、Feng-Shou Liu
DOI:10.1039/c6dt02544g
日期:——
bidentate N,N-palladium complex C3 with both a backbone and N-aryl bulkiness was found to be a highly efficient precatalyst underaerobicconditions. With a low palladium loading of 0.5–0.1 mol%, a variety of heteroarenes with challenging bulky steric aryl bromides as well as heteroaryl bromides are all applicable for this cross-coupling reaction.