A general synthesis of a new type of heterodiene, the
N-vinyl nitrone, is described. The synthetic sequencebegins with the conjugate addition of benzeneselenol to nitroalkenes (in turn derived from Henry reactionof an aldehyde and a nitroalkane) to provide 2-selenenylnitroalkenes. These selenonitroalkanes are reducedto the corresponding hydroxylamines which are combined with aldehydes to form nitrones. Thephenylselenenyl-containing nitrones are then oxidized to selenoxides which undergo
syn-selenoxideelimination to provide
N-vinyl nitrones. Three X-ray crystal structures of substituted
N-vinyl nitroneswere obtained. In addition, the first [4+2] cycloaddition of an
N-vinyl nitrone is reported.
