Heck reactions between aryl halides and olefins catalysed by Pd-complexes entrapped into zeolites NaY

Palladium complexes entrapped into zeolite cages have been prepared and cha racterised by MAS-NMR. They exhibit a high activity towards the Heck reacti on of aryl bromides with olefins for small palladium concentrations (0.1 mo l%). The catalysts can be easily separated from the reaction mixture and re used after washing without loss in activity. Except for very large complexe s, no limitation to the diffusion of educts in the zeolite cages was observ ed. As for the homogeneous Heck reaction, the electronic nature of the aryl bromides and the olefins has a dominating effect on the reaction yield and selectivity. The heterogeneous catalysts activate even aryl chlorides unde r standard reaction conditions. (C) 1999 Elsevier Science S.A. All rights r eserved.