PREPARATION OF COBALT(II) COMPLEXES OF BETA-KETO-ESTERS

Using the ethyl. (-)-menthyl and (1-methyl-2-methoxy)ethyl esters of 3-keto-butanoic acid as model compounds, three procedures have been developed for preparing cobalt(II) complexes of beta-keto esters in non-aqueous media. These procedures involve the reaction between the lithium enolate, the caesium enolate and the trimethylsilyl enolate of the beta-keto ester with an appropriate cobalt(II) compound. All three procedures appear applicable to the preparation of other metal(II) complexes and to beta-diketones.