Scope and Limitations of Pd2(dba)3/P (i-BuNCH2CH2)3N-Catalyzed Buchwald?Hartwig Amination Reactions of Aryl Chlorides.

Proazaphosphatrane ligands in combination with Pd2(dba)3 generate highly active catalysts for Buchwald−Hartwig amination of aryl chlorides. In particular, commercially available P(i-BuNCH2CH2)3N is a highly general and efficient ligand, allowing the coupling of an electronically diverse set of aryl chlorides, including chloropyridines, with a wide variety of amines using 1 mol % of Pd at 100 °C. Either a 1:1 or 2:1 ratio of ligand to Pd was found to be effective. This catalyst system performs exceptionally well for sterically hindered substrates, even with only 0.25 mol % of Pd. It is shown that NaOH can also be used as the base (instead of NaO-t-Bu) allowing functionalized substrates to participate in these reactions.