Sonogashira-Type Alkynylation of Aryl Iodides and Bromides by Pd EnCat

Significance

The copper-free Sonogashira-type reaction of aryl halides 1 and alkynes 2 took place in the presence of Pd EnCat^TM (encapsulated palladium catalyst) and pyrrolidine under solvent-free conditions to give the corresponding coupling products in up to 99% yield (16 examples). After the reaction, the catalyst was readily removed from the reaction mixture by simple filtration and reused up to three times without significant loss of its catalytic activity.