Platinum-catalyzed intermolecular hydroamination of terminal alkynes

The hydroamination of terminal alkyl- and arylacetylenes with aniline is catalyzed by platinum(II) bromide, yielding the corresponding imines. Contrary to what has been previously demonstrated for the platinum(II)-catalyzed hydroamination of α-olefins, the presence of n-Bu4PBr has a detrimental effect on the course of the reaction. The hydroamination of 1-hexyne is highly regioselective (Markovnikov) at 60 °C, but the regioselectivity decreases upon increasing the temperature. The hydroamination of phenylacetylene is fully regioselective (Markovnikov) at 100 °C. TON up to 146 were obtained in the presence of a catalytic source of protons.