A codimerization of styrene and ethene can be carried out continuously in a nanofiltration membrane reactor with dendritic Pd complexes such as 1. The selectivity of the reaction is increased considerably under continuous conditions. The activity and selectivity of monomeric model complexes and the dendritic catalysts were compared in batch reactions.

Phosphino carboxylic acid ester terminated G 0 compounds Si{(CH 2 ) 3 SiMe 2 (C 6 H 4 CH 2 OC(O)(CH 2 ) n -CH 2 PPh 2 } 4 (9a and 9b; n ) 1, 2) and the carbosilane dendrimers Si{(CH 2 ) 3 Si((CH 2 ) 3 SiMe 2 (C 6 H 4 -CH 2 OC(O)(CH 2 ) n CH 2 PPh 2 ) 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.

Phosphine functionalised carbosilane dendrimers have been synthesised and their palladium complexes used as catalysts in the allylic alkylation reaction performed in a continuous flow membrane reactor.

Treatment of (R)-[{α-(dimethylamino)ethyl}-η6-benzene]Cr(CO)3 with esters of chloroformic acid leads to stereoselective substitution of the dimethylamino group for a chloro substituent. The reaction can be extended to systems in which the chromium arene complex, after metalation, is diastereoselectively substituted in the ortho position with carbon and silicon electrophiles to generate planar chirality. The chloro group in turn can be replaced stereoselectively for various phosphorus, nitrogen, and oxygen nucleophiles. Both substitution reactions in the benzylic position proceed via retention of configuration. The addition of cyanide is not stereospecific. The phosphine derivatives are efficient catalysts for the enantioselective hydrovinylation of styrene to 3-phenyl-1-butene. X-ray crystal structures establish the absolute configuration of (R)-[(α-chloroethyl)η6-benzene]Cr(CO)3, (R)-[{α-(diphenylphosphanyl)ethyl}-η6-benzene]Cr(CO)3, and (pS,S)-[1-(α-cyanoethyl)-2-methyl-η6-benzene]Cr(CO)3.