A study of the intramolecular dipolar cycloaddition reactions of a series of allenyl and alkynyl nitrones has been carried out. Phenylhydroxylamine readily reacts with o-(1, 2- propadienyloxy) benzaldehyde to give a dioxaazabicyclo [3.2. 1] octene. The intramolecular 3+ 2-cycloaddition of 2-(1, 2-propynyloxy) benzaldehyde and N-methylhydroxylamine was also studied. In this case, the major cycloadduct formed was identified as 4-methyl-2, 5- ...