Classical reagents: new surprises in palladium-catalyzed C--C coupling reactions.

From investigations on a relatively simple concept to identify conditions for promoting Mizoroki-Heck reactions with vinyl tosylates and phosphates, two serendipitous discoveries were made concerning new properties of palladium as a catalyst. In the first case, beta-hydride eliminations well known for alkyl metal complexes were found to be equally feasible with alkenyl metal compounds. And secondly, conditions were found for promoting intermolecular ene-yne couplings via a PdII-H intermediate. This coupling reactions represents an atom economical Mizoroki-Heck type reaction.