Reaction of cyclobutanone with methylhydroxylamine gives N-methylcyclo
butylideneamine N-oxide (2), which spontaneously dimerizes. Cycloaddit
ions of the in situ generated 4-membered exocyclic nitrone 2 with reac
tive dipolarophiles afford the corresponding cycloadducts. Copyright (
C) 1996 Elsevier Science Ltd