Abstract: The [2+2] cycloaddition of chlorosulfonyl isocyanate (CSI) with an alkene is a very effective method for the synthesis of β-lactams. The new type bicyclic β-lactam compound was synthesized by five steps starting from 2-adamantanone employing the [2+2] cycloaddition strategy. Their structures were characterized by 1H NMR、IR spectra and MS techniques, and the structure of 5 was further determined by X-ray single crystal diffraction analyses method. The results indicate that the [2+2] cycloaddition of cyclic alkene 3 with chlorosulfonyl isocyanate proceeded with excellent regio- and stereo-selectivity.

Key words: β-lactam, antibiotic；chlorosulfonyl isocyanate；[2+2]cycloaddition