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.