[7681-65-4] · CuI · Copper(I) Iodide-Potassium Naphthalenide · (MW 190.45)
[4216-48-2] · C10H8K · Copper(I) Iodide-Potassium Naphthalenide · (MW 167.27)
(used to prepare a zerovalent copper species which is particularly effective in promoting the Ullmann condensation, in the production of organocopper compounds, and in cross-coupling of aryl and allylic halides)
Solubility: copper species generated in dimethoxyethane under Ar.
Preparative Methods: by the reduction of Copper(I) Iodide with a stoichiometric concentration of Potassium and ca. 10% naphthalene in DME under Ar, resulting in a gray-black granular solid.
Handling, Storage, and Precautions: the reagent is generated in situ in an inert atmosphere as needed; reactions are usually carried out under argon; use in a fume hood.
The reagent reacts with pentafluorophenyl iodide in DME to yield a solid, presumed to be pentafluorophenylcopper, which subsequently produces decafluorobiphenyl either thermally or by oxidation (eq 1).1 Alternatively, aryl-alkyl coupling (eq 2) can also be effected.1
Aside from this early report, the number of instances in which this method has been used successfully for the purposes intended is limited. Thus, while the substituted biaryl was formed in over 50% yield in the presence of CuI.K(C10H8) (eq 3),2 the corresponding reaction at nitrogen (eq 4) failed.3 Coupling at nitrogen has, however, been reported to be successful in a different system (eq 5).4
Finally, there are suggestions that the procedure described to produce active copper from CuI.K(C10H8) may prove useful in the preparation of cluster compounds5 and in coupling reactions in metallocenes.6
Serge Jasmin & David R. Dalton
Temple University, Philadelphia, PA, USA