1,3-Dipolar Cycloaddition of Isatin-Derived Azomethine Ylides with 2H‑Azirines: Stereoselective Synthesis of 1,3-Diazaspiro[bicyclo[3.1.0]hexane]oxindoles

A regio- and diastereoselective 1,3-dipolar cycloaddition of 2H-azirines with azomethine ylides generated in situ from isatins and α-amino acids has been elaborated, affording an unprecedented aziridine-fused spiro­[imidazolidine-4,3′-oxindole] framework. This one-pot three-component reaction tolerates a wide range of substrates and enables the construction of highly diverse 1,3-diazaspiro­[bicyclo[3.1.0]­hexane]­oxindoles in isolated yields up to 81% under mild conditions.