Heterogeneous catalysts for hydroamination reactions: structure–activity relationship

The catalytic activity of ion-exchanged zeolite BEA for hydroamination reactions, such as the cyclization of 6-aminohex-1-yne and 3-aminopropylvinyl ether and the intermolecular addition of aniline to phenylacetylene, was studied. The most active catalysts were Cu(I)/H-BEA, Rh(I)/H-BEA, and Zn/H-BEA. These catalysts were fully characterized and the oxidation state and the local environment of copper, in particular, were explored with XANES and EPR spectroscopy. For Zn/H-BEA zeolites the catalytic activity of the material was related to the local structure around the zinc cations.