A series of 1,3-dipolar cycloaddition reactions are carried out using cyclodimers
of simple nitrones and various dipolarophiles; substituted isoxazolidines are isolated
and identified. It is proved that such cyclodimers, in solution, are in equilibrium with
their corresponding nitrones and enamines. It is also concluded that aldocyclodimers
are more potent than keto-cyclodimers in establishing a similar equilibrium.