Palladium catalyzed Suzuki coupling reactions using cobalt-containing bulky phosphine ligands

Three bulky mono-dentate alkyne-bridged dicobalt-phosphine complexes (μ-PPh₂CH₂PPh₂)Co₂(CO)₄](μ,η-PhCCPPh₂) 4a, (μ-PPh₂CH₂PPh₂)Co₂(CO)₄](μ,η-Me₃CCCPPh₂) 5a and (μ-PPh₂CH₂PPh₂)Co₂(CO)₄](μ,η-Me₃SiCCPPh₂) 6a were prepared from the reactions of the bis(diphenylphosphino)methylene (dppm) bridged dicobalt complex Co₂(CO)₆(μ-Ph₂PCH₂PPh₂) with PhCCPPh₂1, Me₃CCCPPh₂2, and Me₃SiCCPPh₂3, respectively. These three metal-containing compounds 4a, 5a and 6a were employed as ligands, replacing conventional organic phosphines, in the Suzuki cross-coupling reactions and have been proved to be effective, authentic mono-dentate phosphine ligands.