Aqueous cross-coupling: highly efficient Suzuki-Miyaura coupling of N-heteroaryl halides and N-heteroarylboronic acids

The palladium complex of the new disulfonated 9-(3-phenylpropyl)9'-PCy2-fluorene ligand is a highly active catalyst for aqueous Suzuki coupling reactions of N- heterocyclic chlorides and N-heterocyclic boronic acids; catalyst loadings of 0.02-0.1 mol% of Pd and two equiv. of phosphine result in the near quantitative formation of the respective coupling products at 100 degrees C.