Direct Access to Isotopically Labeled Aliphatic Ketones Mediated by Nickel(I) Activation.

An extensive range of functionalized aliphatic ketones with good functional-group tolerance has been prepared by a NiI -promoted coupling of either primary or secondary alkyl iodides with NN2 pincer NiII -acyl complexes. The latter were easily accessed from the corresponding NiII -alkyl complexes with stoichiometric CO. This Ni-mediated carbonylative coupling is adaptable to late-stage carbon isotope labeling, as illustrated by the preparation of isotopically labelled pharmaceuticals. Preliminary investigations suggest the intermediacy of carbon-centered radicals.