Vinylmagnesium Chloride-Copper(I) Chloride


[3536-96-7]  · C2H3ClMg  · Vinylmagnesium Chloride-Copper(I) Chloride  · (MW 86.81) (CuCl)

[7758-89-6]  · ClCu  · Vinylmagnesium Chloride-Copper(I) Chloride  · (MW 99.00)

(mediates conjugate addition in the synthesis of b-vinyl carbonyl compounds1-3 and 1,6-diketones4)

Solubility: sol ether, THF.

Preparative Method: generated2 in situ by stirring vinylmagnesium chloride5 in THF with varying amounts of anhydrous Copper(I) Chloride below 0 °C.

Handling, Storage, and Precautions: all reactions must be conducted in the absence of moisture and oxygen. Some reactions have been conducted satisfactorily in THF under reflux conditions.3 Use in a fume hood.

Conjugate Additions.

The reagent mediates a conjugate 1,4-addition of a vinyl group to a,b-unsaturated carbonyl compounds (eq 1) to give b-vinyl derivatives.1 With diethyl (E)-2-heptenedioates as the substrates, the initial conjugate addition is followed by Dieckmann condensation of the resultant ester enolate (eq 2).2 Ring opening of g-lactones by this reagent produces a transient vinyl ketone, which undergoes subsequent conjugate addition with the reagent to also give b-vinyl ketones (eq 3).3 A similar tandem reaction with esters produces the unsaturated ketones accompanied by 1,6-diketones (eq 4).4 In a few cases studied, substitution of a carboxylic acid for the ester in this reaction results in the exclusive formation of the diketone. This synthetic approach to 1,6-diketones appears to be limited to the use of fatty acids as the substrates.4

Related Reagents.

Methylmagnesium Iodide-Copper(I) Chloride; Vinylcopper; Vinylmagnesium Bromide-Copper(I) Iodide.

1. Von Fraunberg, K. Ger. Patent 2 432 232, 1976 (CA 1976, 84, 164 171s).
2. Bunce, R. A.; Harris, C. R. JOC 1992, 57, 6981.
3. Fujita, T.; Suga, K.; Watanabe, S.; Kawata, O.; Kurihara, H. Yuki Gosei Kagaku Kyokaishi 1977, 35, 916 (CA 1977, 88, 120 580c).
4. Watanabe, S.; Suga, K.; Fujita, T.; Takahashi, Y. CJC 1972, 50, 2786.
5. Watanabe, S.; Suga, K.; Suematsu, Y.; Suzuki, T. AJC 1968, 21, 531.

Lucjan Strekowski & Dong-Feng Hou

Georgia State University, Atlanta, GA, USA

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