Ring-Expansion Reactions of Epoxy Amides and Enamides: Functionalized Azetidines, Dihydrofurans, Diazocanes, or Dioxa-3-azabicyclonon-4-enes?

Functionalized azetidines, 2,3-dihydrofurans, or the unorthodox dioxa-3-azabicyclonone-4-ene motifs are the products from transition metal-free reaction between N -oxiranylmethyl benzenesulfonamide and β-chloro-cinnamaldehyde, depending on whether one uses either NaI/K 2 CO 3 or LiBr/K 2 CO 3 . These ring expansion reactions involve enamide (X-ray evidence) derived from N -oxiranylmethyl benzenesulfonamide and β-chloro-cinnamaldehyde as an intermediate. The N -oxiranylmethyl benzenesulfonamide itself upon heating gives readily separable and crystalline isomeric diazocanes that can be characterized by X-ray crystallography.