C−S Bond Formation Reaction between a Phenolate and Disulfide-Bridged Dicopper(I) Complexes

A novel C−S bond formation reaction took place, when a lithium
phenolate derivative was treated with a disulfide-bridged dicopper(I) complex or a bis(μ-thiolato)dicopper(II) complex under very mild
conditions. The reaction has been suggested to proceed via a
disulfide-bridged (μ-phenoxo)dicopper(I) complex as the common
reaction intermediate. Copper(II) complexes of the modified ligands
containing a thioether group (products of the C−S bond formation
reaction) have been isolated and structurally characterized by X-ray
analysis as model compounds of the active site of galactose
oxidase. Mechanism of the C−S bond formation reaction is also
discussed in relation to the biosynthetic mechanism of the organic
cofactor Tyr-Cys of galactose oxidase.