Switchable C or C-N Insertion into N-Alkyl Enamines for Divergent Synthesis of 3-Aminopyrroles or...

A switchable, metal-free cascade that converts N-alkylenamines into either 3-aminopyrroles or CF₃/CN-functionalized 1,2-dihydropyrazines in a single operation is reported. Simply by alternating the electronic nature of the enamines, the reaction manifold is redirected from a formal [4 + 1] C-insertion to a [4 + 2] C-N-insertion pathway. Both cascades proceed under mild, open-flask conditions without external photocatalyst or Lewis acid, delivering medicinally relevant heterocycles in 52%-89% yield. The 3-aminopyrrole series tolerates aryl, heteroaryl, ester and free-NH substituents, whereas the 1,2-dihydropyrazine branch provides direct access to CF₃ or CN groups that are otherwise difficult to install. The protocol streamlines the construction of two distinct nitrogen heterocycles from a common enamine platform, offering a rare example of reactivity-controlled divergent synthesis in C-C and C-N bond formation.