An alkene moiety substituted with two different metals provides a unique opportunity for onward functionalization chemistry, as was explored with β-silyl vinylgold(I) systems. Al-C and Cu-C bonds are known to possess differing hard/soft character, and therefore species such as 2-Et/2-Pr,Ph could be viewed as potentially discriminating bifunctional nucleophiles. In initial studies carbon monoxide was chosen to explore onward functionalization, in part because such an insertion step might lead to the formation of a hitherto unprecedented copper acyl complex. Group 9 acyl compounds are well known, and critical in industrial hydroformylation. Likewise, Fe-bound acyl units can act as structural models of the Fe hydrogenase active site. For copper, however, these unstable species have been proposed as intermediates in Cu-catalysed reactions such as borocarbonylation and amidation, but have not been isolated, due to their propensity to undergo facile rearrangement.