The Sonogashira coupling reaction is not catalyzed by AuI/dppe in the absence of Pd complexes. However, addition of 0.1 mol % of Pd(0) led to efficient cross-coupling reactions. The most plausible catalytic cycles for the Au-catalyzed cross-coupling reactions have been examined and are unlikely in the absence of Pd contamination.
![Unlikeliness of Pd-free gold(I)-catalyzed Sonogashira coupling reactions](https://www.iciq.org/wp-content/uploads/2014/03/Unlikeliness-of-Pd-free-goldI_3006.gif)