Synthesis of bicyclic y-lactam derivatives by intramolecular carbene insertion and aza-Wittig reaction

Department of Chemistry, Indian Institute of Technology, Kharagpur-721 302, West Bengal, India E-mail : absk@chem.iitkgp.ernet.in Manuscript received 27 June 2013, accepted 28 June 2013 A comparative study of the various methodologies to construct bicyclic \(\gamma\)-lactams is reported. Thus RhII - catalyzed decomposition of 2-pyrrolidone and pyrrolidine derived diazomalonates were attempted to synthesize fused ylactams. Spectral evidences revealed the formation of diastereomeric alcohols instead of desired C-H or N-H insertion products, indicating significant conformational bias towards insertion process. On the other hand, the method involving the N-H insertion onto the lactam nitrogen of 2-pyrrolidone ring was successful. Intramolecular aza-Wittig reaction was also successfully explored to construct bicyclic \(\gamma\)-Iactam scaffolds. All the bicyclic analogues showed weak antibacterial activity against \(S\). \(aureus\) and \(E\). \(coli\)