Formyl Substituent at C-4 of Pyrazoles: A Temporary Protecting Group for Regioselective Palladium-Catalyzed Direct Arylation at C-5
作者:Imen Smari、Chiraz Youssef、Kedong Yuan、Anissa Beladhria、Hamed Ben Ammar、Bechir Ben Hassine、Henri Doucet
DOI:10.1002/ejoc.201301593
日期:2014.3
Pyrazoles with an aldehyde function at C-4 underwent a palladium-catalyzeddirectarylation reaction to provide a regioselective approach to 5-aryl-substituted pyrazoles. The reaction proceeds in moderate to high yields with a variety of aryl bromides in the presence of 2 mol-% of Pd(OAc)2 as the catalyst. The use of an aldehyde function at C-4 of the pyrazoles presents several advantages: (1) 4-formylpyrazoles