Highly efficient, recyclable palladium catalyst immobilized on organic-inorganic hybrid material: Application in the Heck reaction

摘要

Palladium immobilized on organic-inorganic (silica gel) hybrid materials behaves as a very efficient heterogeneous catalyst in Heck reactions. lodoarenes, 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.