A polystyrene supported [PdCl-(SeCSe)] complex: a novel, reusable and robust heterogeneous catalyst for the Sonogashira synthesis of 1,2-disubstituted alkynes and 1,3-enynes

3,5-Bis((phenylselanyl)methyl)phenol has been synthesized as a novel SeCSe pincer type pre-ligand from commercially available 5-hydroxy isophthalic acid through a multistep synthesis. Then, a polystyrene-supported SeCSe pincer ligand and its corresponding palladium complex were prepared and characterized using different techniques including FT-IR, SEM/EDX, TG/DTG, and XPS. The amount of palladium incorporated into the polymer matrix as determined by ICP analysis was obtained to be 3.64 wt% (0.34 mmol g(-1)). The PS[PdCl-SeCSe] catalytic activity has been evaluated in the Sonogashira coupling of diverse aryl halides with aromatic and aliphatic terminal alkynes. It was also noted that less reactive and inexpensive aryl bromides and aryl chlorides have been successfully cross-coupled with terminal alkynes using low catalyst loading. Moreover, the developed methodology is effective for the stereoselective preparation of substituted 1,3-enynes.