Modern Ullmann-Type Couplings

Ligand-promoted, copper-catalyzed, Ullmann-type couplings of aryl halides (I, Br, Cl) with various nucleophiles, including amines, hetarenes, amides, hydrazines, alcohols, phenols, thiols, sulfinates, and active methylene compounds, are reviewed in this chapter.
Considerable attention has been paid to demonstrate the powerful acceleration effect of second-generation oxalic amides as ligands in modern Ullmann-type couplings. Under these catalyst systems, less-reactive but inexpensive (het)aryl chlorides can be employed as coupling partners. Moreover, the catalyst loading for coupling of aryl iodides and bromides can be reduced to <1 mol% in most cases.