Synthesis of planar chiral ferrocenyl 1,3-diamines and 1,3-amino ethers

Abstract

The efficient syntheses of novel planar chiral 1,3-diamines and 1,3-amino ethers with an oxy or amino function directly bound to the cyclopentadienyl ring of ferrocene has been developed. The key reaction is the Cu₂O promoted substitution of (pR)-N,N-diisopropyl-2-iodoferrocenecarboxamide with either phthalimide or AcOH to introduce nitrogen or oxygen functionality onto the cyclopentadienyl ring. The enantiomerically pure iodoferrocene derivative is available from the known enantioselective ortho-lithiation of N,N-diisopropylferrocenecarboxamide with n-BuLi–sparteine. In the course of these studies the synthesis of a novel C₂ symmetric C-2 dimer of N,N-dimethyl-1-ferrocenylethylamine was characterised by single crystal X-ray diffraction.