52007-95-1Relevant academic research and scientific papers
Two flavors of PEPPSI-IPr: Activation and diffusion control in a single NHC-ligated Pd catalyst?
Larrosa, Igor,Somoza, Clara,Banquy, Alexandre,Goldup, Stephen M.
, p. 146 - 149 (2011)
Abnormal reactivity has been observed in Negishi, Suzuki-Miyaura, and Kumada-Tamao-Corriu cross-couplings in which PEPPSI-IPr (where PEPPSI stands for pyridine enhanced precatalyst preparation, stabilization, and initiation and IPr refers to the NHC ligand) is employed, implicating the presence of two distinct Pd0 species in the catalytic cycle. Polybrominated arenes and organometallic reagents react selectively to give the product of exhaustive polysubstitution regardless of the initial reaction stoichiometry. Competition experiments suggest that, after an initial activation controlled oxidative addition, reductive elimination produces an ultrareactive Pd0 species which consumes all remaining C-Br bonds in the molecule under diffusion control.
