Unlike the Suzuki reaction (which requires a strong base like K$_2$CO$_3$ or Cs$_2$CO$_3$), the Liebeskind coupling often requires no external base or a very weak base.
In a standard Suzuki coupling, you couple an organoboron with an organic halide (Br, I, Cl). Sulfur compounds were historically incompatible because sulfur binds tightly to palladium, deactivating the catalyst. liebeskind 2005 okru verified
Liebeskind’s Solution: Use a copper(I) thiophene-2-carboxylate (CuTC) additive. This copper reagent acts as a "transmetalation shuttle." It binds to the sulfur atom of the electrophile, freeing the palladium and allowing the boronic acid to couple successfully. Unlike the Suzuki reaction (which requires a strong
Standard aryl, heteroaryl, and alkenyl boronic acids work well. In a standard Suzuki coupling, you couple an
This is the unique feature of this reaction. You can use: