Preparation and chemistry of the active copper species derived from CuI.PBu3, CuI.PPh3, and CuCN.nLiX complexes

Highly reactive copper reagents were prepared by reduction of CuI.PBu3, CuI.PPh3, and CuCN.nLiX copper (I) complexes in a 3-step process. This involved reduction of the complex using lithium naphthalenide; oxidation at -78 to -35 degrees Celsius for alkyl bromides and -35 to 0 degrees Celsius for aryl bromides; and finally, reaction with an electrophile to form the product. Control of reduction temperature was an important factor in the process. The advantages and disadvantages of each copper complex are discussed.