A catalytic-enantioselective entry to planar chiral pi-complexes: enantioselective methoxycarbonylation of 1,2-dichlorobenzene-Cr(CO)(3)

The palladium-catalyzed mono-methoxycarbonylation of 1,2-dichlorobenzene tricarbonylchromium(0) has been achieved with up to 95% ee in the presence of the chiral ferrocene ligand (R,S)-PPF-pyrrolidine. It was found that the enantioselectivity strongly depends on the reaction time (conversion). Obviously, the initial enantioselectivity is enhanced by a subsequent kinetic resolution connected to the formation of the bis-methoxycarbonylated byproduct.