Development of efficient and reusable diarylphosphinopolystyrene-supported palladium catalysts for C-C bond forming cross-coupling reactions

Short and versatile syntheses of reusable diarylphosphinopolystyrene-supported palladium catalysts 3a-j are described. The bis(o-tolyl)phosphino catalyst 3b is particularly efficient for the Suzuki and Sonogashira cross-couplings, whereas the bis(m-tolyl)phosphino catalyst 3c is the most active catalyst for Heck reactions. The couplings are performed under non-anhydrous reaction condition.,; and require only low amounts of supported palladium (0.5 mequivs. for Suzuki-Miyaura, 1.0 mequiv. for Sonogashira and 0.5 mequivs. for Heck reactions could be sufficient). Catalysts 3a-j are recovered by filtration and can be reused more than four times with no loss of efficiency.