Rhodium- and Palladium-Catalyzed Hydroarylation of Propargylic Amines with Arylboronic Acids

The hydroarylation of 3-arylprop-2-yn-1- amine derivatives with arylboronic acids has been studied in the presence of rhodium or palladium catalysts. By using a rhodium-based catalytic system, b,g-diarylallylamines were isolated in good yields. By contrast, the formation of the regiosomeric g,g-diarylallylamines was achieved by means of a palladium catalyst in the presence of acetic acid. The complementary regioselectivity displayed by these two processes is a consequence of different catalytic cycles, involving respectively carborhodation or hydropalladation of the coordinated alkyne as key steps. Calculated charge distributions in the p-complexes are in accord with the results obtained