Abstract
N-Arylation of imidazoles with arylboronic acids was efficiently carried out in the presence of a catalytic amount of SiO2-NHC-CuI in methanol at room temperature under base-free reaction conditions. The reactions of a variety of arylboronic acids with imidazoles generated the corresponding products N-arylimidazoles in good to excellent yields. In addition, SiO2-NHC-CuI could be recovered and recycled for six consecutive trials without significant loss of its reactivity.
GRAPHICAL ABSTRACT
ACKNOWLEDGMENTS
We gratefully acknowledge financial support by the National Natural Science Foundation of China (20972057) and the Natural Science Foundation of Anhui (No. 090416223).
Notes
a SiO2-NHC-CuI(containing Cu 0.05 mmol, 5 mol%), imidazole (1.1 mmol), and phenylboronic acid (1.0 mmol) was carried out in solvent (3.0 mL) at 50 °C for 3 h under air.
b Isolated yields.
a SiO2-NHC-CuI(containing Cu 0.05 mmol, 5 mol%), azole (1.1 mmol), and arylboronic acid (1.0 mmol) was carried out in CH3OH (3.0 mL) at 50 °C for 3 h under air.
b Isolated yields.
a Reused SiO2-NHC-CuI (containing Cu 0.05 mmol, 5 mol%), imidazole (1.1 mmol), and phenylboronic acid (1.0 mmol) was carried out in CH3OH (3.0 mL) at 50 °C for 3 h under air.
b Isolated yields.