Selective Syntheses of Planar-Chiral Ferrocenes

Planar-chiral ferrocenes are widely applied in catalytic asymmetric transformations in scientific research as well as in industry. A plethora of different methodologies have been developed to access these molecules with a high degree of regio- and stereoselectivity. The aim of this contribution is to give a comprehensive overview of this topic. The synthesis of 1,2- and 1,3-substituted ferrocenes by electrophilic aromatic substitution, ortho-directed metalation, kinetic resolution, and desymmetrization is discussed. Advantages and disadvantages are highlighted.