Diastereoselective conjugate additions to alkoxycarbene cations of the iron chiral auxiliary [(η5-C5H5)Fe(CO)(PPh3)C(OMe)CHCHR]+

Conjugate additions to alkoxycarbene cations of the iron chiral auxiliary [(η5-C5H5)Fe(CO)(PPh3)C(OMe)CHCHR]+ proceed with high diastereoselectivity. Subsequent protonation and demethylation gives iron acyl complexes of opposite relative configuration to those which result from conjugate addition of the same nucleophile to the corresponding α,β-unsaturated iron acyl complex.235