Synthesis of Novel Chiral Spiroisoxazolidine‐β‐Lactams from 6‐Alkylidenepenicillanates: A 1,3‐Dipolar Cycloaddition Approach

The synthesis of a library of 6‐alkylidene‐β‐lactams, derived from 6‐aminopenicillanic acid is reported. The 1,3‐dipolar cycloaddition of these 6‐alkylidenepenicillanates with nitrones was explored as an approach to synthesize novel chiral spiroisoxazolidine‐β‐lactams. Quantum chemical calculations, at the DFT level of theory, were carried out to elucidate the 3D structure of the synthesized compounds. The reported methodology, which involves the generation of three new consecutive stereogenic centers, proved to be regio‐ and stereoselective, leading to novel chiral spiroisoxazolidine‐penicillanates efficiently.