Photoinduced Copper(II) Catalyzed Decarboxylative Homocoupling of Arylpropiolic Acids: A Facile Access to the Symmetrical 1,3‐Diynes

We have developed an efficient visible light induced copper‐mediated protocol to synthesize conjugated 1,3‐diynes viadecarboxylative homocoupling of arylpropiolic acids. A variety of electron‐rich and electron‐deficient acids worked well in this methodology providing desired product upto 99% yield. Detailed mechanistic investigations including UV‐Vis spectroscopy and in‐situIR experiments have been carried out to elucidate the plausible reaction mechanism. Compared to previously reported thermal strategies, this new pathway occurs at room temperature, employs greener solvent and aerial oxygen as an oxidant. We have demonstrated a photoinduced copper mediated decarboxylative homocoupling of arylpropiolic acids to synthesize, 3‐diynes. A variety of arylpropiolic acids containing electron‐rich as well as electron‐deficient groups undergo conversion to afford the conjugated 1,3‐diynes. Detailed mechanistic studies were carried out to understand the mechanism. The synthesized molecule was successfully applied for post‐functionalization to afford compounds having utility in various fields.