An efficient phosphine-free direct C–Harylation of thiophenes at the α-position has been developed at low catalyst loading of bis(alkoxo)palladium complex (Cat.I, 0.1–0.2 mol %). The developed synthetic method can be applied to the synthesis of α-aryl/heteroaryl thiophenes from aryl or heteroaryl bromides in good to excellent yields and is compatible with the substrates bearing electron-donating or
Palladium‐Catalysed Direct C‐H Activation/Arylation of Heteroaromatics: An Environmentally Attractive Access to Bi‐ or Polydentate Ligands
作者:Fazia Derridj、Aditya L. Gottumukkala、Safia Djebbar、Henri Doucet
DOI:10.1002/ejic.200800143
日期:2008.6
Bi- or polydentateligands based on heterocycles can be easily prepared by palladium-catalysed C–H bond activation of heteroaromatics followed by heteroarylation with heteroaryl bromides. A variety of heteroaromatics such as furans, thiophenes, pyridines, thiazoles or oxazole derivatives have been employed and moderate to good yields were generally obtained using the air-stable complex [PdCl(dppb)(C3H5)]
The direct C-H heteroarylation of thiophenes, promoted by rigid α-diimine palladium complexes is described. This approach exhibits broad substrate scopes with functional group tolerant, and proceeds with the formation of regioselective products.