[2.2.3]Cyclazines are obtained in moderate yields by reaction of 3H-pyrrolizines bearing conjugative substituents (Ph or CO2Me) with vinamidinium salts in the presence of strong bases. Syntheses of the previously unknown 2-phenyl-3H-pyrrolizine and 1-methoxycarbonylcyclopenta [h] [2.2.4] cyclazine are also described.