Cooperative Catalyst Effects in Palladium-Mediated Cyanation Reactions of Aryl Halides and Triflates
摘要:
Substoichiometric quantities of copper or zinc species dramatically improve both conversion rate and efficiency of Pd(0)-catalyzed cyanation reactions. The optimum reaction conditions involve the use of a nitrile solvent, NaCN, and a catalyst system employing the combination of cuprous iodide with tetrakis(triphenylphosphine)palladium(0) [Pd(PPh3)(4)]. Beneficial effects were observed for the conversion of aryl halides, aryl triflates, and a vinyl bromide to the corresponding nitriles. The process was demonstrated on preparative scale with a broad range of aromatic and heteroaromatic substrates containing diverse functionality. A dual catalytic cycle is proposed to explain the profound influences of the cocatalyst system.