With use of Cu-based catalysts, 2- and 4-hydroxypyridines were N-arylated in modest to excellent yields. In the case of 2-hydroxypyridine, the use of 4,7-dimethoxy-1,10-phenanthroline, 3, expanded the scope of previous literature reports to include the use of N-containing heteroaryl halides, and 2-substituted aryl halides. In addition, by using a copper catalyst based on 2,2,6,6-tetramethylheptane-3,5-dione, 4, the first N-arylations of 4-hydroxypyridines and O-arylations of 3-hydroxypyridines with aryl bromides and iodides have been accomplished.
“Cu-Catalyzed N- and O-Arylation of 2-, 3-, and 4-Hydroxypyridines and Hydroxyquinolines”, Org. Lett., 2007, 9(4), 643-646.