Simple syntheses of Co < inf > 2 < /inf > (CO) < inf > 8 < /inf > and NaCo(CO) < inf > 4 < /inf > reagents by the reduction of CoCl < inf > 2 < /inf > (or CoBr < inf > 2 < /inf > ) under carbon monoxide at atmospheric pressure

Abstract

The reduction of CoCl2 by MgH2 in tetrahydrofuran in the presence of carbon monoxide gives Co2(CO)8, which on treatment with an alkyne and norbornene gives the Pauson-Khand reaction. The reduction of CoCl2 or CoBr2 by sodium naphthalenide in THF in the presence of carbon monoxide gives NaCo(CO)4, which has been used for cyclization of certain benzylic halides into the corresponding cyclic ketones. © 1991.