Stereoselective synthesis of planar chiral 2,2′-diarylsubstituted ferrocene derivatives as precursors for new 2-phospha[3]ferrocenophanes

Starting from a 1,1′-bis-(SC)-(methoxymethyl)pyrrolidine functionalized ferrocene, an ortholithiation/iodination/chiral auxiliary removal/Suzuki coupling sequence has been achieved. It affords a convenient, stereoselective access to chiral, C2-symmetric, tetrasubstituted ferrocene derivatives of (Spl,Spl)-configuration, bearing various aryl substituents and acetoxymethyl functions. These α-acetoxy-functionalized ferrocenes may be useful synthetic intermediates. In this work they were used as precursors for two new enantiomerically pure (Spl,Spl)-2-phospha[3]ferrocenophanes for organocatalytic purposes.