Synthetic Approaches to New Diastereomerically Pure Ferrocenyl Trisphosphines Combining Phosphorus, Planar, and Carbon Chirality

Abstract

Two new diastereomeric ferrocenyl triphosphine ligands P3Chir 1 and 2 have been conveniently synthesized through a multi-step reaction sequence starting from (R)-(S)-diphenylphosphinoferrocenylamine [(R)-(S)-PPFA]. Chromatographic resolution of the diborane protected-phosphine oxide derivatives, followed by a stereoconservative reduction/deboronation step, gave the pure triphosphines P3Chir in which the planar chirality of the ferrocenyl unit is combined with phosphorus and carbon stereocenters in an unprecedented molecular assembly.