substrates represents a major challenge of the present cross‐coupling methodology. The nickel‐catalyzed Kumada cross‐ coupling of tertiary alkyl Grignard reagents with arylbromides allows this difficult reaction with numerous different substrates. Optimal results were obtained using sterically demanding, bifunctional N‐heterocyclic carbene ligands.
In this study, nickel-catalyzedcoupling reactions between arylhalides and tert-alkyl Grignardreagents were developed. Our original bicyclic NHC ligands reduced the formation of isomerized products, and we found that NMP as a co-solvent suppressed the reduction process. Under the optimal conditions we developed, the catalyst loading was lowered to 0.5 mol %, and catalyst loading using ortho-substituted
Palladium-Catalyzed Hiyama Cross-Couplings of Aryl Arenesulfonates with Arylsilanes
作者:Liang Zhang、Jie Wu
DOI:10.1021/ja804672m
日期:2008.9.17
Palladium-catalyzed efficient Hiyama cross-coupling reaction of arylarenesulfonate with arylsilane is described. The desired carbon-carbon bond formation proceeds under mild conditions with good functional group tolerance.
Palladium-Catalyzed Suzuki−Miyaura Cross-Couplings of Aryl Tosylates with Potassium Aryltrifluoroborates
作者:Liang Zhang、Tianhao Meng、Jie Wu
DOI:10.1021/jo7019064
日期:2007.11.1
[Graphics]Pd-catalyzed Suzuki-Miyaura cross-coupling reaction of aryl tosylates with potassium aryl trifluoroborate in the presence of bulky and electron-rich phosphine ligand is described. In addition, a useful chemoselective coupling of an aryl chloride in the presence of a tosyloxy group was demonstrated.
Romadan; Berga, Zhurnal Obshchei Khimii, 1958, vol. 28, p. 413,416; engl. Ausg. S. 405, 407