Scope and limitations of Pd2(dba)3/P(i-BuNCH2CH2)3N-catalyzed Buchwald-Hartwig amination reactions of aryl chlorides.
Proazaphosphatrane ligands in combination with Pd(2)(dba)(3) generate highly active catalysts for Buchwald-Hartwig amination of aryl chlorides. In particular, commercially available P(i-BuNCH(2)CH(2))(3)N 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 degrees 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.
Urgaonkar
Sameer
S
Department of Chemistry, Gilman Hall, Iowa State University, Ames, Iowa 50011-3111, USA.
Verkade
John G
JG