A general synthesis of a new type of heterodiene, the N-vinyl nitrone, is described. The synthetic sequence begins with the conjugate addition of benzeneselenol to nitroalkenes (in turn derived from Henry reaction of an aldehyde and a nitroalkane) to provide 2-selenenylnitroalkenes. These selenonitroalkanes are reduced to the corresponding hydroxylamines which are combined with aldehydes to form nitrones