Search results for "ligands effects"

Direct arylation of heterocycles: the performances of ferrocene-based polyphosphane ligands in palladium-catalyzed C-H bond activation

2010

International audience; The palladium-catalyzed direct arylation of alkylated- furan, thiophene, and thiazole and benzoxazole heterocycles with electronically and sterically deactivated bromoarenes was selectively and efficiently promoted by ferrocenyl polyphosphanes. In this C[BOND]H bond activation reaction of heteroaromatics, the performances of polydentate di-, tri-, and tetraphosphane ligands were compared, showing that the triphosphane 1,1′,2-tris(diphenylphosphino)-4-tert-butylferrocene 3 was the most effective for the coupling. The introduction of more electron-donating (iPr) or electron-withdrawing (furyl) groups on the phosphorus atoms did not improve the ligand performances. The …