Catalytic System‐Controlled Divergent Reaction Strategies for the Construction of Diversified Spiropyrazolone Skeletons from Pyrazolidinones and Diazopyrazolones

Abstract A catalytic system‐controlled divergent reaction strategy was here reported to construct four types of intriguing spiroheterocyclic skeletons from simple and readily available starting materials via a precise chemical bond activation/[ n +1] annulation cascade. The tetraazaspiroheterocyclic and trizazspiroheterocyclic scaffolds could be independently constructed by a selective N−N bond activation/[ n +1] annulation cascade, a C(sp 2 )‐H activation/[4+1] annulation and a novel tandem C(sp 2 )‐H/C(sp 3 )−H bond activation/[4+1] annulation strategy, along with a broad scope of substrates, moderate to excellent yields and valuable transformations. More importantly, in these transformations, we are the first time to capture a N−N bond activation and a C(sp 3 )−H bond activation of pyrazolidinones under different catalytic system.