The asymmetric synthesis of β-lactams. Stereocontrolled asymmetric tandem Michael additions and alkylations of α,β-unsaturated acyl ligands bound to the chiral auxiliary [(η5-C5H5)Fe(CO)(PPh3)]

✍ Scribed by Stephen G. Davies; Isabelle M. Dordor-Hedgecock; Kevin H. Sutton; Jonathan C. Walker

• Publisher: Elsevier Science
• Year: 1986
• Tongue: French
• Weight: 234 KB
• Volume: 27
• Category: Article
• ISSN: 0040-4039
• DOI: 10.1016/s0040-4039(00)83881-2

✦ Synopsis

Michael addition of lithium benzylamide to the enantiomerically pure (S)-E-crotonyl complex of C(~5-C,H,)Fe(CO)(PPh~)l 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 (OS)-(-)-4-methyl-N-benzyl-B-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-B-lactam.

We have recently reported that the chiral auxiliary [(n"-C,H,)Fe(CO)(PPh,)1 exerts