Reaction
- Cobalt(I)-catalyzed, steroselective olefination of alkylzinc reagents with aryl aldehydes.
- Reagent for the reductive radical dimerization of 3-haloindoline derivatives.
- Cobalt-catalyzed, asymmetric addition of silylacetylene to 1,1-disubstituted allenes.
Description
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.
Uses
A stoichiometric reducing agent that is used in the radical dimerization of halogenated organic molecules.
Uses
A stoichiometric reducing agent employed in the radical dimerization of halogenated organic molecules.
Preparation
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.
reaction suitability
core: cobalt
reagent type: catalyst
storage
Chlorotris(triphenylphosphine)cobalt is fairly stable in air; it has been stored under
N2 atmosphere over several months at rt.
References
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.
