Amino acid-promoted Ullmann-type coupling reactions and their applications in organic synthesis

Ullmann-type coupling reactions between aryl halides and N-containing reagents, phenols, and other related nucleophilic agents are very valuable transformations for organic synthesis. Their conventional reaction conditions require high reaction temperatures. We describe here that some amino acids, either as substrates or ligands, can lead Cu-catalyzed C-N, C-O, C-S, and C-C bond formations work at relatively low temperatures. An ortho-substitution effect caused by NHCOR groups is discussed. Applications of these newly developed reactions to heterocycle preparation and asymmetric synthesis are also presented.