Synthesis, characterization and the crystal structures of novel achiral and chiral α-ferrocenyl α-aminophosphine oxides

Abstract

Novel achiral α-ferrocenyl α-aminophosphine oxides ( 2a– 2e) have been prepared by the reaction of ferrocenylaldimines ( 1a– 1e) with Ph 2PLi at room temperature in 63–92% yield. Similarly, starting from l-phenylalaninol derived ferrocenylaldimine ( 3), the corresponding ( S, S)-phosphine oxide ( 4) and its ( R, S)-diastereomer ( 5) were isolated by fractional crystallization in 41% and 16% yield, respectively. All the achiral and chiral α-aminophosphine oxides were air-stable and easily accessible. They were fully characterized by elemental analysis, 1H NMR, 31P NMR and IR spectra. In addition, structures of 2e and 4 have been determined by X-ray single-crystal analysis.