Planar-Chiral P And N-Bridged Diferrocenes

We describe the synthesis of planar-chiral diferrocene compounds4,7and12,intended as key precursors for a new family of asymmetric catalyst ligands with less complex structures than their popular equivalents. In contrast to conventional 1,2-disubstituted ferrocenes containing center-chiral and planar-chiral elements, these compounds are purely planar-chiral due to the absence of alpha-substiuted ethyl groups. The title compounds4,7and12were obtained from known precursors in 87%, 59% and 60% yields, respectively.