Phosphine-Scavenging Cationic Gold(I) Complexes: Alternative Applications of Gold Cocatalysis in Fundamental Palladium-Catalyzed Cross-Couplings

We have demonstrated that air-stable cationic gold(I) cocatalysts have the capacity to enhance the efficiency of palladium-catalyzed cross-couplings. Specifically, we determined that a 1:1 [Pd{P(t-Bu)3}2]/[Au{P(t-Bu)3}(NTf2)] system provides superior reactivity relative to [Pd{P(t-Bu)3}2], across Suzuki-Miyaura, Stille, and Mizoroki-Heck reactions performed under mild conditions. Our results are consistent with cationic gold(I) species serving primarily as phosphine scavengers in this chemistry, as recently predicted by density functional theory (DFT).