A New Biarylphosphine Ligand for the Pd-Catalyzed Synthesis of Diaryl Ethers Under Mild Conditions

摘要

A new bulky biarylphosphine ligand (>L8) has been developed that allows the Pd-catalyzed C–O cross-coupling of a wide range of aryl halides and phenols under milder conditions than previously possible. A direct correlation between the size of the ligand substituents in the 2′, 4′ and 6′ positions of the non-phosphine containing ring and the reactivity of the derived catalyst system was observed. Specifically, the rate of coupling increased with the size of these substituents.