Synthesis of a new iron Lewis acid catalyst possessing a chelating cyclopentadienyldiphenylphosphinite ligand, (η5:η1-C5H4CH(Ph)OPPh2)

A new iron Lewis acid catalyst, [(η5:η1-C5H4CH(Ph)OPPh2)Fe(CO)(THF)]+[BF4]− featuring a cyclopentadienyl ring that is tethered to a terminal diphenylphosphinite moiety was created. This is the first complex to contain a chelating η5:η1-cyclopentadienyl-phosphinite ligand. This new racemic iron Lewis acid was tested and found to be an effective catalyst in an aziridine-forming reaction. An asymmetric alcohol that is a precursor of the chiral catalyst was synthesized with greater than 95% ee. Upon ligation of the diphenylphosphinite to the iron center, a 3:2 mixture of diastereomers was formed. The diastereomeric mixture of the asymmetric catalysts was utilized in the aziridine-forming reaction and produced the cis-aziridine with low enantiomeric excess.