Recent advances in the development of polycyclic skeletons via Ugi reaction cascades

Isocyanide-based multicomponent reactions are among the most powerful synthetic tools available. Particularly, the isocyanide-based Ugi reaction can allow rapid preparation of -aminoacyl amide derivatives and polyazaheterocycles with extensive pharmaceutical applications. Moreover, bridged polyazaheterocycles, including one or more quaternary carbon centers, can be constructed via the Ugi cascade reaction in a few steps. This review will emphasize synthesis and bioactivities of bridged compounds with quaternary centers constructed through Ugi cascade reactions.