C‐2 Arylation of Piperidines through Directed Transition‐Metal‐Catalyzed sp³ CH Activation

All you need is an open vial! The direct α arylation of cyclic alkylamines (see scheme) requires an open vial, as the hydrogen atom involved in the C(sp3)H-activation process is ultimately released as hydrogen gas. Reports on the formation of hydrogen gas in direct transition-metal-catalyzed functionalizations are still rare. Open-vial reactions proved crucial to this direct arylation procedure as, upon sealing, catalyst deactivation occurs.