THE ASYMMETRIC SYNTHESIS OF β-LACTAMS. STEREOCONTROLLED ASYMMETRIC TANDEM MICHAEL ADDITIONS AND ALKYLATIONS OF α,β-UNSATURATED ACYL LIGANDS BOUND TO THE CHIRAL AUXILIARY 5-C5H5)Fe(CO)(PPh3)>

Article abstract of DOI:10.1016/S0040-4039(00)83881-2

Michael addition of lithium benzylamide to the enantiomerically pure (S)-E-crotonyl complex of <(η⁵-C5H5)Fe(CO)(PPh3)> followed by trapping of the resultant enolate with methyl iodide or methanol occurs with high diastereoselectivity and gives after decomplexation the essentially optically pure (3R),(4S)-(-)-3,4-dimethyl- and (4S)-(-)-4-methyl-N-benzyl-β-lactams respectively.Similarly, tandem addition of lithium benzylamide and methylation of the corresponding enantiomerically pure R-(-)-acryloyl complex gave after decomplexation the essentially optically pure (3S)-(-)-3-methyl-N-benzyl-β-lactam.