Bimetallic Cu/Pd Catalysts with Bridging Aminopyrimidinyl Phosphines for Decarboxylative Cross-Coupling Reactions at Moderate Temperature

A bimetallic catalyst system is presented that enables the decarboxylative cross-coupling of triflates with carboxylate salts at only 100 degrees C, which is 70 degrees C lower than with previous Cu/Pd-based systems. The new protocol allows the coupling of a broad range of aryl triflates with various substituted 2-nitrobenzoates in good to excellent yields. The key feature of the catalyst system is a bidentate P,N-ligand designed to bridge the Pd and Cu centres and thereby facilitating the rate-determining transmetalation step. Mass spectrometry (ESI-MS) studies support the ability of the aminopyrimidinyl phosphine to simultaneously coordinate copper and palladium.