Palladium nanoparticles supported on Smopex® metal scavengers as catalyst for carbonylative Sonogashira reactions: Synthesis of ?,?-alkynyl ketones

Palladium nanoparticles supported on two Smopex com. metal scavengers (1% wt./wt.) have been tested in the carbonylative Sonogashira reactions of aryl iodides with phenylacetylene. Their catalytic activity has been compared with those of more common catalysts (Pd/C, Pd/?-Al2O3). Pd/Smopex-234 resulted esp. effective in the synthesis of alkynyl ketones even working with a low amt. of palladium (0.2-0.5 mol%). Preliminary heterogeneity tests (i.e. hot filtration test, Pd leaching and recycle of the catalyst) have been performed in order to evaluate the catalytic behavior of this system. The obtained results seem to indicate that Pd/Smopex-234 could act as a truly heterogeneous catalyst.