Application of a ferrocene-based palladacycle precatalyst to enantioselective aryl-aryl Kumada coupling

The palladium catalysed reaction of 1-iodo-2-methylnaphthalene and 2-methyl-1-naphthylmagnesium bromide gave quantitatively an ( S a )-configured cross-coupled product in 80% e.e. using ( R , S p )-PPFA as a ligand. N , N -Dimethylaminomethylferrocene was cyclopalladated (Na 2 PdCl 4 , ( S )-Ac-Phe-OH, 93% e.e., as determined by 1 H NMR as a result of self-induced non-equivalence), and the resulting ( S p )-configured dimeric palladacycle was employed as a precatalyst for this cross-coupling reaction (5 mol%). Addition to the palladacycle of diphenylphosphine and subsequent base-promoted bidentate ligand synthesis and palladium capture gave an in situ generated catalyst resulting in an ( S p )-configured product in up to 71% e.e.