Recent progress in copper-catalyzed cross-coupling reactions

The cross-coupling reaction of unsaturated carbons is one of the most important methods in organic synthesis. It has been widely used in the manufactures of dyes, pharmaceuticals, polymers, and many other fine chemicals. Due to their low price and toxicity, Cu salts have recently emerged as novel catalysts in cross-coupling reactions of unsaturated carbons, whose replacement of toxic and expensive Pd or Ni catalysts will greatly improve the chemical industry in both the economic and environmental aspects. In this review the newest development of the Cu catalysts in cross-coupling reactions was summarized. C-C, C-N, C-O, C-S, as well as C-X coupling reactions were reviewed. The article also provided detail information about the effects of Cu salts, ligands and solvents on the efficiency of the cross-coupling reactions.