CHLOROTRIS(TRIPHENYLPHOSPHINE)COBALT(I)

1. Cobalt(I)-catalyzed, steroselective olefination of alkylzinc reagents with aryl aldehydes.
2. Reagent for the reductive radical dimerization of 3-haloindoline derivatives.
3. Cobalt-catalyzed, asymmetric addition of silylacetylene to 1,1-disubstituted allenes.

Chlorotris(triphenylphosphine)cobalt is a monovalent cobalt complex; homogeneous catalyst for hydrogenation and hydrodimerization of alkenes; strong nucleophile, reacting with alkyl acyl halides to afford coupling products; useful for the preparation of organocobalt complexes.

A stoichiometric reducing agent that is used in the radical dimerization of halogenated organic molecules.

A stoichiometric reducing agent employed in the radical dimerization of halogenated organic molecules.

Preparative Methods of Chlorotris(triphenylphosphine)cobalt: a solution of Cobalt(II) Chloride hexahydrate (0.6 g, 2.5 mmol) and Triphenylphosphine (2.0 g, 7.6 mmol) in EtOH (70 mL) was treated under N2 and stirring with a solution of Sodium Borohydride (0.08 g, 2.1 mmol) in EtOH at 30-40 °C; the resulting brown-green precipitate was washed several times with EtOH and water and dried (yield 92%);^[1] reductions with powdered Zn, and electrolysis, are equally effective methods; corresponding Br and I complexes are prepared similarly from CoBr2 and CoI2.

core: cobalt
reagent type: catalyst

Chlorotris(triphenylphosphine)cobalt is fairly stable in air; it has been stored under N2 atmosphere over several months at rt.

1. (a) Aresta, M.; Rossi, M.; Sacco, A. ICA 1969, 3, 227. (b) Holah, D. G.; Hughes, A. N.; Hui, B. C.; Kan, C. T. CJC 1978, 56, 814.