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.