Efficient One-Pot Synthesis of the Unsymmetrical Diarylalkynes from Two Different Aryl Bromides and Propiolic Acid by Using Pd(PPh3)4 Catalyst

Unsymmetrical diarylalkynes have attracted much atten-tion, as the molecule structure, having an internal alkyne of two different aromatics, is a core in materials encountered π-conjugated systems.1 Palladium catalyzed Sonogashira reaction is the most commonly used method for the arylation of terminal alkynes.2 Instead of the terminal alkynes, the decarboxylative Sonogashira reaction is used from the alkyne carboxylic acids has several advantages, including a depreci-able process for the treatment of the carbon dioxide as a reaction waste released after the complete conversion, and is stable for handling and storage.3 We reported a method for unsymmetrical coupling products from the site selective reaction of propiolic acid with aryl iodides and aryl bro-mides combinations.4 Unlike trimethylsilylacetylene and 2-methylbut-3-yn-ol, Propiolic acid as an alkyne source is ver