Cross-Coupling Catalysis by an Anionic Palladium Complex

Recent
studies have shown that anionic palladium complexes are
viable catalysts for a range of catalytic cross-coupling reactions.
We present a one-step synthesis of the anionic “ligandless”
palladium complex [NBu4]­[Pd­(DMSO)­Cl3] together
with its crystal structure. This compound has been shown to be an
active precatalyst in the Mizoroki–Heck reaction. Under Jeffery
conditions, activated aryl chlorides can be coupled in yields of up
to 94% without the need of an additional ligand. The presence of a
small amount of water was necessary for product formation. An Amatore–Jutand-type
catalytic cycle is consistent with the results presented herein. For
comparison with the known mixed complex [(pym-Im-Me)2PdCl]­[Pd­(DMSO)­Cl3], the cationic complex [(pym-Im-Me)2PdCl]­PF6 (pym = pyrimidyl, Im = imidazolin-2-ylidene) has been synthesized
and characterized using standard techniques.