Copper-Mediated CDC Systems

Palladium is used in the majority of biaryl CDC reactions however copper would be an ideal economical alternative since it is abundant and relatively inexpensive. It has seen historical use in oxidative naphthyl homocouplings to synthesize chiral ligands like BINOL (l,l -bi-2-naphthol). Although, due to the radical nature of the reaction, the heterocoupling of naphthyls has proved to be a difficult task since radical-radical recombination produces a 

The presence of the NHC ligands greatly effects the electronic properties of the Cu(ii) making it possible to cross-couple naphthyls. The CDC was believed to proceed via a radical-addition mechanism. 

Aryl-Aryl Coupling via Cross-Dehydrogenative-Coupling Reactions 

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