Alkyne‐Dependent Synthesis of Pyrrolines and Propargylamines through Metal‐Free Decarboxylation

Pyrrolines are crucial in the discovery and development of pharmaceuticals. Herein, a metal‐free multicomponent decarboxylative reaction has been developed that is extremely effective and brief. The reaction is performed to form iminium salt intermediates through decarboxylative condensation of N ‐benzylglycines and formaldehyde. Subsequent chemoselective [3 + 2] cyclization or nucleophilic addition of alkynes leads to the generation of various pyrrolines or propargylamines in moderate to good yields, respectively. The approach is environmentally benign, easily implemented, and tolerates a wide range of functional groups.