Asymmetric synthesis of planar-chiral ferrocenes by Mo- or Ru-catalyzed enantioselective metathesis

Kinetic resolution of planar-chiral 1,1'-diallylferrocene derivatives was realized by Mo- or Ru-catalyzed asymmetric ring-closing metathesis (RCM). The Mo catalyst showed much better performance than the Ru catalyst in the present reactions, and nearly perfect resolution of the racemic ferrocenes was achieved. This is the first example of highly enantioselective metal-catalyzed methods of preparing optically active planar-chiral metallocenes.