Phosphino carboxylic acid ester functionalized carbosilane dendrimers: Nanoscale ligands for the Pd-catalyzed hydrovinylation reaction in a membrane reactor

Phosphino carboxylic acid ester terminated G(0) compounds Si{(CH2)(3)SiMe2(C6H4CH2OC(O)(CH2)(n)CH2PPh2}(4) (9a and 9b; n = 1, 2) and the carbosilane dendrimers Si{(CH2)(3)Si((CH2)(3)SiMe2(C6H4CH2OC(O)(CH2)(n)CH2PPh2)(3)}(4) (10a and 10b; n := 1, 2) have been prepared as hemilabile nanoscale ligands for the palladium-catalyzed codimerization of olefins. The hydrovinylation of styrene was carried out in a continuously operated nanofiltration; membrane reactor. Under continuous conditions, the selectivity of the reaction is increased considerably. Monomeric model complexes; and the dendritic catalysts were compared for their activity and selectivity in batch reactions. The Pd catalyst complexes were prepared in situ from the dendritic ligands and an (allyl)palladium(II) precursor.