Calcium cuprates

Presumably, this new complex is a calcium cuprate. Reaction of the organocalcium reagent prepared from an organic halide and the highly reactive calcium, with benzoyl chloride in the absence of a Cu(I) salt, afforded a complex mixture of products. However, in the presence of a Cu(I) salt, high yields of ketone formation were observed. Table 9.2 presents some of the ketone formation reactions of the calcium cuprates with benzoyl chloride. 

This cuprate also underwent the conjugate addition with acyclic enones, for example, 2-hexene-4-one, to give 5-methyl-3-tridecanone in 47% yield. We have not attempted further optimization. Reaction of this calcium cuprate with a sterically hindered enone, for example, isophorone, produced <3% of the desired compound in 24h. The isolated yield, however, increased to 84% when the additives BF3 etherate and chlorotrimethylsilane [12] were used. In the aryl case, / -tolylcalcium cuprate also underwent this transformation with 2-cyclohexenone to give 3-(p-methylphenyl)cyclohexanone in reasonable yield (Table 9.3). 

Scheme 9.3 Reactions of organocalcium and calcium cuprate reagents prepared from chloromethylated polystyrene and Rieke calcium.

Table 9.6 Reactions of calcium cuprate reagents from chloromethylated polystyrene and Rieke calcium with various electrophiles.

Standard Gibbs-energy functions (A,tj° eq. 2) of formation of calcium cuprates from oxides according to Risold et al. (1995) units have been omitted... 

In line with Ca being the least electropositive of the A elements, calcium cuprate carbonates are the least stable in this array. 

Transmetalation of phenylcopper(I) with activated calcium leads to the formation of sparingly soluble [(thf)3Ca(p-Ph)3Ca(thf)3] [Ph-Cu-Ph] , according to Scheme 11 [108]. The solvent-separated calcium cuprate(I) compound consists of a phenyl-calcium cation and a [Ph2Cu] counter-anion. The calcium atoms in the... 

Krieck S, Gorls H, Westehausoi M (2010) Structinal diversity of calcium cuprates via additimi and transmetalation reactions of mesity copper(I). Chem Asian J 5 272-277... 

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