C4-Alkylamination of C4-Halo-1H-1-tritylpyrazoles Using Pd(dba)2 or CuI.
Alkylamino coupling reactions at the C4 positions of 4-halo-1H-1-tritylpyrazoles were investigated using palladium or copper catalysts. The Pd(dba)2 catalyzed C-N coupling reaction of aryl- or alkylamines, lacking a β-hydrogen atom, proceeded smoothly using BuDavePhos as a ligand. As a substrate, 4-Bromo-1-tritylpyrazole was more effective than 4-iodo or chloro-1-tritylpyrazoles. Meanwhile, the CuI mediated C-N coupling reactions of 4-iodo-1H-1-tritylpyrazole were effective for alkylamines possessing a β-hydrogen atom.
['Usami|Yoshihide|Y|0000-0002-6475-048X', 'Tatsui|Yuya|Y|', 'Yoneyama|Hiroki|H|', 'Harusawa|Shinya|S|']
D002384:Catalysis D003300:Copper D010165:Palladium D011720:Pyrazoles
Pd(dba)2 4-halopyrazole Buchwald-Hartwig coupling CuI mediated coupling aliphatic amine amination