Intramolecular hydroamination catalysed by Ag complexes stabilised in situ by bidentate ligands

A series of silver complexes generated in situ from AgOSO2CF3 (AgOTf) and a range of bidentate ligands were investigated as catalysts for the intramolecular hydroamination of 4-pentyn-1-amine. A variety of P- and N-donor ligands were tested including the novel pyrazole-phosphine ligand 1-(2-(diphenylphosphino) phenyl) pyrazole. The best catalyst was formed from equimolar amounts of the P, N-donor ligand 1-(2-(diphenylphosphino)ethyl)pyrazole and AgOTf, which achieved a turnover rate of 129 h (1) for the cyclisation of 4-pentyn-1-amine. (C) 2008 Elsevier B. V. All rights reserved.