Phosphane-Free Palladium-Catalyzed Coupling Reactions: The Decisive Role of Pd Nanoparticles.

Nanosized palladium colloids, generated in situ by reduction of Pd(II) to Pd(0) [Eq. (a)], are involved in the catalysis of phosphane-free Heck and Suzuki reactions with simple palladium salts such as PdCl(2) or Pd(OAc)(2), as demonstrated by transmission electron microscopic investigations.