Radical cyclisation of epoxynitrile-2-azetidinones mediated by Cp2TiCl

The reductive radical cyclisation of δ- and ɛ-epoxynitrile-2-azetidinones has been achieved using titanocene monochloride. The reaction was regioselective and afforded bicyclic β-lactams and tricyclic β-lactams containing an aryl group fused to a seven-membered ring.