Abstract
An efficient method has been developed for the Pd-catalyzed cross-coupling reactions of electron-deficient heteroaromatic amines with heteroaryl halides. The optimized reactions used Pd2(dba)3 as catalyst, 1,1′-bis(diphenylphosphino)ferrocene (DPPF) as ligand, and Cs2CO3 as base. The Pd-catalyzed cross-coupling reactions of several rarely reported electron-deficient heteroaromatic amines were successfully accomplished in good yields.
GRAPHICAL ABSTRACT
ACKNOWLEDGMENTS
The authors thank the Global Alliance for TB Drug Development and the National Science and Technology Project of China (No. 2009ZX09102-054) for financial support of this project.
Notes
a Reaction conditions: 1a (1.0 equiv, 2.0 mmol), 1b (1.5 equiv), catalyst (2 mol%), ligand (8 mol%), base (1.5 equiv).
b The products were purified by flash silica-gel chromatography.
c All yields are reported for isolated and purified products.
d IPr · HCl, 1,3-bis(2,6-diisopropylphenyl)imidazolium chloride.
a Reactions run with 2.0 mmol of heteroaromatic amine in 20 mL of toluene solvent at 110 °C. Pd2(dba)3 was used in combination with 4.0 equiv of ligand/Pd.
b The products were purified by flash silica-gel chromatography.
c Isolated yields are an average of at least two runs.
d The yield was reported in the literature under different reaction conditions from that of Ref.[ Citation 13 ]