Cascade spiro-heterocyclization of pyrrolo[1,2-a][4,1]-benzoxazepinetriones under the action of carbocyclic enaminoketones

Spiro-heterocyclization of pyrrolo-[1,2-а][1,4]benzoxazine-1,2,4-triones was formerly described as occurring under the action of carbocyclic [1, 2], heterocyclic [3–5], and acyclic enamines [6, 7] and proceeding through successive attack of β-CH and NH groups of enamino fragment of enamines on the carbon atoms in the positions 3а and 4 of pyrrolobenzoxazinetriones with the cleavage of the oxazinone ring at the С–О bond. The reactions of pyrrolo[1,2-а][4,1]benzoxazepine-1,2,4-triones with enamines has not been investigated before.