The decisive role of ligand metathesis in Au/Pd bimetallic catalysis.

AuClL(1)/PdCl2L(2)2 cocatalyzed coupling of Ar(1)X and Ar(2)SnBu3 is feasible for bulky Ar(1), provided that at least one ligand on Pd is not strongly coordinating. This can be achieved in situ by Au/Pd ligand exchange if L(1) is weakly coordinating. When the exchange is slow, independent preparation of appropriate catalysts is recommended.