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

Article abstract of DOI:10.1021/jo000433k

Phosphino carboxylic acid ester terminated G₀ compounds Si{(CH₂)₃SiMe₂(C₆H₄ CH₂OC(O)(CH₂)_nCH₂PPh₂} ₄ (9a and 9b; n = 1, 2) and the carbosilane dendrimers Si{(CH₂)₃ Si((CH₂)₃SiMe₂(C₆H₄ CH₂OC(O)(CH₂)_nCH₂PPh₂) ₃}₄ (10a and 19b; 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.