Zirconium/Nickel-Mediated One-Pot Ketone Synthesis

A zirconium/nickel-mediated one-pot synthesis of ketones is reported. In the presence of Zn or Mn, Cp2ZrCl2 was found to dramatically accelerate the coupling and suppress side product formation via an I -> SPy displacement at the same time. Unlike Zn/Pd- and Fe/Cu-mediated one-pot ketone syntheses, the new method is effective for nucleophiles bearing OR or equivalent functional groups at the alpha-position. A mechanism comprising a nickel catalytic cycle, a zirconium catalytic cycle, and Zr -> Ni transmetalation is proposed, and Cp2ZrCl2 and/or low-valent Zr species are suggested to play crucial dual roles.