Synthesis of a-amino g-butyrolactone derivatives by aziridination of a-ylidene g-butyrolactones

The reactions of exocyclic a,b-unsatd. g-lactones with 4-O2NC6H4SO3NHCO2Et and CaO produce N-(ethoxycarbonyl) spiroaziridino g-lactones. The products are cleaved by acetic acid to afford acetylated N-protected a-amino g-butyrolactones. The ring opening reaction is quantitative and highly regioselective.