Allenyloxime—a new source of heterocyclizations to stable cyclic nitrones

A variety of conditions including reductive and/or basic reagents in aqueous or alcoholic solution was applied to 2,2-dimethylpenta-3,4-dienal oxime. Formation of various five-membered heterocycles with excellent chemical selectivity was observed. Most of the reactions yielded cyclic nitrones with stable dipolar structure and unique functionalities present. All products of cyclization were isolated and fully characterized.