Gold carbonyl oxygen atom

Backvall has reported the gold(III)-catalyzed cycloisomerization of allene-substituted malonic esters to form p,Y-unsaturated 6-lactones [115]. For example, treatment of allenyl malonate derivative 76 with a catalytic 1 3 mixture of AUCI3 and AgSbF in acetic acid at 70 °C led to isolation of 8-lactone 77 in 99% yield (Eq. (12.41)). The transformation was restricted to substrates that contained a terminally disubstituted allenyl moiety and presumably occurs via nucleophilic attack of the carbonyl oxygen atom on a gold-complexed allene followed by acetate-mediated demethylation and protodeauration. 

Another possibility would be the use of allylic esters, which after a gold-catalyzed cycloisomerization with the carbonyl oxygen atom as the nucleophile deliver activated allylic intermediates which at the same time contain a vinylgold substructure. After transfer of an allyl cation to palladium(O), an oxidative addition to palladium, the vinylgold intermediate could transfer the organic moiety to palladium(II). A final reductive elimination would close the catalytic cycle. At the same time, no halide that potentially could deactivate the cationic gold(I) catalyst would be present. Indeed, Blum et al. [30] presented such systems. But... 

The IR spectrum of asparagine adsorbed on a gold electrode shows that it is coordinated via oxygen atoms of COO and through the amide carbonyl.527... 

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