Synthesis and Characterization of Planar-Chiral Cyclopentadienyliron Complexes (<i>S</i>)- and (<i>R</i>)-{η⁵-[1-Ph₂(OH)C-2-Me-4-PhC₅H₂]}Fe(CO)₂R (R = C⋮CPh, Me, SO₂Me)

Abstract

The first enantiomerically pure planar-chiral cyclopentadienyliron complexes, ( S )- and ( R )-η 5 -Cp c Fe(CO) 2 R [Cp c = 1-hydroxydiphenylmethyl-2-methyl-4-phenylcyclopentadienyl; R = C⋮CPh ( 6 ), Me ( 8 )], in which the locus of chirality is in the cyclopentadienyl center, were synthesized from Cp a Fe(CO) 2 I ( 4a: Cp a = 1-(−)-menthoxycarbonyl-2-methyl-4-phenylcyclopentadienyl) and Cp b Fe(CO) 2 I ( 4b: Cp b = 1-(+)-menthoxycarbonyl-2-methyl-4-phenylcyclopentadienyl) and were isolated as a diastereomerically pure form by fractional recrystallization. The molecular structures of 4a and 4b, including the absolute configuration, have been established by an X-ray crystallographic analysis based on the configuration of the (−)- and (+)-menthyl groups.