Synthesis of some new polycyclic aromatic monocyclic B-lactams

In this paper the synthesis of some new polyaromatic monocyclic B-lactams has been reported. These cycloadducts have been synthesized by the [2+2] ketene-imine cycloaddition reaction known as the Staudinger reaction. All of the products have been fully characterized by IR, 1H-NMR, 13C-NMR, mass spectroscopy and elemental analyses. The X-ray crystal structure of a cis B-lactam has been also presented. The cycloaddition reaction was found to be totally diastereoselective leading exclusively to the formation of the cis-B-lactams for 3c-e, 3g, 3i-k, 3p and the rest were found to be totally trans.