Solvent effect on palladium-catalyzed cross-coupling reactions and implications on the active catalytic species

Suzuki coupling of the bifunctional substrate 1 using Pd(2) (dba)(3) ]/PtBu(3) gives selectivity for C?Cl in nonpolar solvents but for C?OTf in polar solvents. The results of computational and experimental studies suggest that the catalytically active species in polar solvents under conditions employing coordinating additives is inconsistent with monoligated Pd(PtBu(3) )]. Instead, the data are consistent with an anionic palladium complex as the active species.