New Ortho-Directing Group for Lithiation: Use of a Methoxy−Imino Auxiliary for the Synthesis of Chiral Ortho-Substituted Acetyl- and Propionylferrocenes

Ortho lithiation of acetylferrocene and propionylferrocene followed by addition of chlorosilane and diiodoethane was totally enantioselective when a chiral methoxy−imino auxiliary was used as an easily removable ortho-directing group. Enantiopure (R)-o-iodoacetylferrocene and (R)-o-iodopropionylferrocene were obtained. The structure of (R)-o-iodoacetylferrocene was confirmed by X-ray crystallography.