B. Gotov et Hg. Schmalz, A catalytic-enantioselective entry to planar chiral pi-complexes: Enantioselective methoxycarbonylation of 1,2-dichlorobenzene-Cr(CO)(3), ORG LETT, 3(11), 2001, pp. 1753-1756
The palladium-catalyzed mono-methoxycarbonylation of 1,2-dichlorobenzene tr
icarbonylchromium(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 e
nantioselectivity strongly depends on the reaction time (conversion), Obvio
usly, the initial enantioselectivity is enhanced by a subsequent kinetic re
solution connected to the formation of the bis-methoxycarbonylated byproduc
t.