Convenient One-Pot Synthesis of L₂Pd(0) Complexes for Cross-Coupling Catalysis

Abstract

A convenient one-pot synthesis of (tBu3P)2Pd(0) was successfully carried out by using various air-stable Pd(II) salts, such as Pd(cod)Cl2, Pd(nbd)Cl2, Pd(CH3CN)2Cl2, or Pd(PhCN)2Cl2, without the use of an external reducing agent. Using Pd(cod)Cl2 as the precursor, large-scale synthesis of (tBu3P)2Pd(0) was accomplished in excellent yield and purity. Another protocol was also developed for L2Pd(0) complexes via an atom economical one-pot method by reacting in situ generated LPd(R-allyl)Cl complexes (L = tBu3P, Cy3P, (o-Tol)3P, CataXCium A, AmPhos, QPhos: R = H, Me, Ph) with 1 equivalent of L in the presence of a base with yields ranging from 74% to 92%, although the process can be further optimized. These methods are superior to those reported in the literature