Synthesis, Characterization of Spirocyclic λ 3 ‐Iodanes and Their Application to Prepare 4,1‐Benzoxazepine‐2,5‐diones and 1,3‐Diynes

Herein, a [3+2] cycloaddition of aza-oxyallylic cations with ethynylbenziodoxolones for synthesis of new λ3 -iodanes containing spirocyclic 4-oxazolidinone has been developed. This cyclic λ3 -iodanes display stability in air and excellent solubility in organic solvent. Using them as substrate, both the 4,1-benzoxazepine-2,5-diones and symmetrical 1,3-diynes derivatives were afforded in high yield under copper(I)-catalyzed conditions.