Copper-Catalyzed Intermolecular Cyclization between Oximes and Alkenes: A Facile Access to Spiropyrrolines

A Cu-catalyzed protocol has been developed for the rapid construction of a wide spectrum of structurally interesting spiropyrroline skeletons. This method utilizes readily accessible ketoximes and alkenes as the starting materials and exhibits broad substrate scope and good functional group compatibility. Furthermore, the reaction can be applied for the late-stage modification of bioactive pregnenolone derivatives. The mechanistic investigation suggests that the reactions proceed through a radical process.