Unprotected vinyl aziridines: facile synthesis and cascade transformations.

Functionalized vinylaziridines, readily available from water-stable aziridine aldehydes have led to the construction of a variety of stereochemically rich heterobicycles. A cascade ring-opening/ring-contraction mechanism operates in the course of the process. These results underscore the notion that interesting and useful nitrogen-mediated relay processes can arise when elements of strain are merged with the manifolds of enamine/iminium ion reactivity.