Chemistry of 4-membered cyclic nitrones (2, 3-dihydroazete 1-oxides); a novel one-step synthesis of N-acetoxy β-latams

2,3-dihydroazete 1-oxide 1 reacts at room temperature with base, acid and lead tetraacetate to give the 5-hydroxyisoxazolidines 4a and 4b , the 6H-1,2-oxazin-6-one 7 and the N-acetoxy β-lactam 8, respectively; the reaction with lead tetraacetate represents a simple one-step conversion of a 4-membered cyclic nitrone into a β-lactam.