Reaction of the β-lactam-based oxazolidinone 5 with N-sulfonylimines provides the exo and endo azapenams 8 in 22–54% yield. The reactivity of 2H-azirines as 1, 3-dipolarophiles towards β-lactam-based azomethine ylides derived from oxazolidinones 5 and 15 has also been evaluated. Azirines 11 and 12a provide cycloadducts 13a, b and 16 respectively, which incorporate the novel 2, 6-diazatricyclo [4.2. 0.02, 4] octan-7-one ring system. These ...
