Room temperature ring-opening cyclization reactions of 2-vinylaziridines with isocyanates, carbodiimides, and isothiocyanates catalyzed by

2-Vinylaziridines undergo cycloaddition reactions with various heterocumulenes, in the presence of [Pd(OAc)(2)] and PPh(3), at room temperature and 1 atm pressure, regioselectively affording five-membered ring products in moderate to high yields. The mixture of stereoisomers obtained by reactions employing cis-1-butyl-2-vinyl-3-methylaziridine as the reactant provides evidence for a mechanism involving a eta(3)-eta(1)-eta(3) interconversion of a (pi-allyl)palladium intermediate.