Abstract 1, 3-Dipolar cycloaddition of N-benzyl-C-(methoxycarbonyl) nitrone (3a), N-benzyl- C-phenylnitrone (3b), N-benzyl-C-cyanonitrone (3c), N-(p-methoxybenzyl)-C-cyanonitrone (3d), N-phenyl-(3e) and N-(2-pyridyl)-C-methylnitrones (3f) to bicyclopropylidene (2) gave the corresponding cycloadducts 5a− f in 100, 95, 94, 100, 93 and 71% yields, respectively. Treatment of these bisspirocyclopropanated isoxazolidines with trifluoroacetic acid in ...