Amidophosphine-stabilized palladium complexes catalyse Suzuki-Miyaura cross-couplings in aqueous media

We report a simple and efficient procedure for Suzuki-Miyaura reactions in aqueous media catalysed by amidophosphine-stabilized palladium complexes trans-{(LPPh2)-P-3}(2)PdCl2 (3), trans-{L(3)PPhtBu}(2)PdCl2 (4), [Pd(eta(3)-C3H5)((LPPh2)-P-3)Cl] (5) and {Pd[2-(Me2NCH2)C6H4]((LPPh2)-P-3)Cl} (6). The acidity of the NH proton in complexes 3-6 plays an important role in their catalytic activity. In addition, the palladium complexes cis-{(LPPh2)-P-1}PdCl2 (1) and trans-{(LPPh2)-P-2}(2)PdCl2 (2) stabilized by phosphines containing Y, C, Y-chelating ligands L-1,L-2 have also been found to be useful catalysts for Suzuki-Miyaura reactions in aqueous media. The method can be effectively applied to both activated and deactivated aryl bromides yielding high or moderate conversions. The catalytic activity of couplings performed in pure water increases when utilizing a Pd complex with more acidic NH protons. A decrease of palladium concentration from 1.0 to 0.5 mol% does not lead to a substantial loss of conversion. In addition, Pd complex 1 can be efficiently recovered using two-phase system extraction. Copyright (C) 2016 John Wiley & Sons, Ltd.