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.
A convenient phosphine-free palladium-catalyzed direct arylation of thiazole under mild aerobic conditions
作者:Xiao-Xi He、Yan-Fang Li、Ju Huang、Dong-Sheng Shen、Feng-Shou Liu
DOI:10.1016/j.jorganchem.2015.12.009
日期:2016.2
A series of bulky amine palladium complexes [(Ar-NH2)2PdCl2]} were synthesized and characterized. The catalytic activity of the palladium complexes was evaluated via the direct C–H arylation of thiazoles with aryl bromides in aerobic conditions at 80–100 °C. Under the optimal conditions, 0.5–0.05 mol% of the bulky palladium complexes were found to be very efficient and produced the desired cross-coupling
Metal-complexes bearing C1- and C2-symmetric N- Heterocyclic Carbene (NHC) ligands were prepared from prochiral NHC precursors. As predicted by DFT calculations, our strategy capitalizes on the formation of a metal-carbene bond which induces an axis of chirality. Configurationally stable atropisomers of various NHC containing TM-complexes were isolated by preparative HPLC on a chiral stationary phase in good
imidazolinium salts, chiral transitionmetalcomplexes containing an N-heterocyclic carbene (NHC) ligand were prepared (metal = palladium, copper, silver, gold, rhodium). Axial chirality in these complexes results from the formation of the metal-carbene bond leading to the restriction of rotation of dissymmetric N-aryl substituents about the C–N bond. When these complexes exhibited a sufficient configurational
resolution of racemic complexes and provided a straightforward access to complexes with excellent enantiopurities (>99.5% ee). Enantiopure complexes were studied by crystal X-ray diffraction and electronic circular dichroism (ECD). Their configuration stabilities were investigated both experimentally and theoretically through the determination of the rotational barrier values. These complexes were tested for