Mizoroki-Heck Cross-coupling Reactions Catalyzed by Dichloro{bis[1,1',1''-(phosphinetriyl)tripiperidine]}palladium Under Mild Reaction Conditions

Abstract

Dichloro-bis(aminophosphine) complexes of palladium with the general formula of [(P{(NC5H10)3-n(C6H11)n})2Pd(Cl)2] (where n = 0-2), belong to a new family of easy accessible, very cheap, and air stable, but highly active and universally applicable C-C cross-coupling catalysts with an excellent functional group tolerance. Dichloro{bis[1,1',1''-(phosphinetriyl)tripiperidine]}palladium [(P(NC5H10)3)2Pd(Cl)2] (1), the least stable complex within this series towards protons; e.g. in the form of water, allows an eased nanoparticle formation and hence, proved to be the most active Heck catalyst within this series at 100 °C and is a very rare example of an effective and versatile catalyst system that efficiently operates under mild reaction conditions. Rapid and complete catalyst degradation under work-up conditions into phosphonates, piperidinium salts and other, palladium-containing decomposition products assure an easy separation of the coupling products from catalyst and ligands. The facile, cheap, and rapid synthesis of 1,1',1"-(phosphinetriyl)tripiperidine and 1 respectively, the simple and convenient use as well as its excellent catalytic performance in the Heck reaction at 100 °C make 1 to one of the most attractive and greenest Heck catalysts available.We provide here the visualized protocols for the ligand and catalyst syntheses as well as the reaction protocol for Heck reactions performed at 10 mmol scale at 100 °C and show that this catalyst is suitable for its use in organic syntheses.