Allylic substitution with dendritic palladium catalysts in a continuously operating membrane reactor

Dendrimers are a rather new class of macromolecules, which are by now at the edge of technical application. A number of dendritic catalysts have been described, but in most cases catalyst recyclization is an unsolved problem. The present article describes the retention of diaminopropyl-type dendrimers bearing palladium phosphine complexes by ultra- or nanofiltration membranes and their use as catalysts for the allylic substitution in a continuously operating chemical membrane reactor. Retention rates are higher than 99.9% resulting in a sixfold increase of the total turnover number for the Pd catalyst. (C) 1999 Academic Press.