Palladium immobilized on organic-inorganic (silica gel) hybrid materials behaves as a very efficient heterogeneous catalyst in Heck reactions. Iodoarenes, bromoarenes, as well as activated chloroarenes react smoothly with olefins to afford the corresponding cross-coupling products in good to excellent yields under phosphine- and amine-free reaction conditions in the presence of palladium immobilized on 3-[(2-aminoethyl)amino]propyl-functionalized silica gel (Silica-AAPTS-Pd) or palladium immobilized on 3-aminopropyl-functionalized silica gel (Silica-APTS-Pd) as catalyst. The silica-supported palladium catalyst could be recovered and recycled by simple filtration of the reaction solution, and used for more than ten consecutive trials without significant loss of catalytic activity.
Heck reaction - organic-inorganic hybrid material - palladium immobilization - heterogeneous catalysis