N–H activation vs. C–H activation: ruthenium-catalysed regioselective hydroamination of alkynes and hydroarylation of an alkene with N-methylaniline

Phenylacetylene and its derivatives undergo regioselective insertion into the N–H bond of N-methylaniline in the presence of Ru3(CO)12 catalyst to afford N-methyl-N-(α-styryl)anilines in high yields, whereas styrene reacts with the ortho C–H bond of N-methylaniline giving 2-(1-phenylethyl)-N-methylaniline.