A water-soluble pyridyl-triazole ligand for aqueous phase palladium catalyzed Suzuki–Miyaura coupling†
An environmentally friendly water-soluble ligand has been prepared by “clicking” 2-(azidomethyl)pyridine with but-3-ynyl sodium sulphate. In situ combination of the new ligand with [Pd(η3-C3H5)Cl]2 (Pd : ligand = 1 : 1) provides a highly active catalytic system for the Suzuki–Miyaura reaction. Coupling of phenylboronic acid with a variety of aryl or heteroaryl bromides is carried out at catalyst loadings of 0.01% or lower under conventional heating. The aqueous catalytic phase may be used three times without loss of activity.