CHEMISTRY OF I-MEMBERED CYCLIC NITRONES (2,3_DIHYDROAZETE l-OXIDES); A NOVEL ONE-STEP SYNTHESIS OF N-ACETOXY B-LACTAMS

Abstract: 2,3-Dihydroazete l-oxide 1. reacts at room temperature with base, acid and lead tetraacetate to give the 5-hydroxyisoxazolidines 4a and e, the 6H-1,2-oxazin-6-one 7 and the N-acetoxy $-lactam S, respectively:?he reaction with lead tetraacetate Represents a simple one-step conversion of a 4-membered cyclic ni-trone into a f3-lactam. Recently we reported the first synthesis of 'stable ' 4-membered cyclic nitro-nes (2,3-dihydroazete l-oxides) by the reaction of nitroalkenes with ynamines (l-1 aminoacetylenes). Since these 2,3-dihydroazete l-oxides are isomeric with B-lac-tams we are now investigating routes to effect this isomerization. Because of the current interest i