Two new N-heterocyclic carbene palladacycle complexes [1,3-N,N'-bis(2,6-disubstituted phenyl)imidazolin-2-ylidene]chloro[2-dimethylaminomethylphenyl-C,N]palladium(II) [R＝i-Pr (3a), methyl (3b)] have been synthesized, and evaluated as catalyst precursors for aminations of aryl chlorides with various amine coupling partners. It was found that 3a with bulky substituents around Pd center is better than 3b for catalyzing the amination of 4-methylphenyl chloride with morpholine in the presence of sodium tert-butoxide.

Key words: N-heterocyclic carbene, Pd catalyst, C—N bond-forming reaction