phenyselenenyl bromide to afford ring closure reaction products deriving by the intramolecular capture of the seleniranium intermediates by the oxygen atom. Owing to the relative positions of the oxygen atom and of the carbon-carbon double bond in the nitrones employed, six-memberedcyclic iminium salts were thus formed. These have ben directly treated with nucleophilic reagents and afforded 1,2-oxazine derivatives