Reactions
The synthetic utility of organocadmiums is limited. The alkyl groups in them are less nucleophilic than the organozincs due to the general increase in electronegativity going down group 12. This reduced reactivity is demonstrated in the conversion of acid chlorides to ketones with these reagents. This reaction was discovered by Henry Gilman in 1936 and was used until less toxic cuprates were available. With other organometallic reagents such reaction would continue to the corresponding alcohol.
An example of the synthetic use of an organocadmium is the reaction of diisoamylcadmium with β-carbomethoxypropionyl chloride to methyl 4-keto-7-methyloctanoate without reacting further with the ketone group or the ester group.
Another example is the use of methyl cadmium in one of the steps leading to cholesterol total synthesis:
Dimethylcadmium is also used in the synthesis of colloidal nanocrystals although its toxic and volatile nature has led researchers to look elsewhere for cadmium precursors such as cadmium oxide.
This selectivity exists provided that the reaction is carried out salt free. When the cadmium reagent is generated in situ from a cadmium salt, the presence of a halide salt makes the reagent much more reactive, even to ketones. The same salt effect can be observed with organozinc compounds.
Read more about this topic: Organocadmium Compound
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