Pd-catalyzed decarboxylative coupling of propiolic acids: one-pot synthesis of 1,4-disubstituted 1,3-diynes via Sonogashira-homocoupling sequence.

One-pot synthesis of symmetric 1,4-disubstituted 1,3-diynes from iodoarenes and propiolic acid via Sonogashira reaction followed by Pd-catalyzed decarboxylative homocoupling is developed in high yields. Also, this system allows the one-pot synthesis of unsymmetric 1,4-disubstituted 1,3-diynes by cross-coupling of two different 3-substituted propiolic acids.